Do maize crop models catch the impact of future [CO2] on maize yield and water use?. iCROPM2016 I... more Do maize crop models catch the impact of future [CO2] on maize yield and water use?. iCROPM2016 International Crop Modelling Symposium
ABSTRACT Soils with subsoil clay accumulation account for more than 20% of the global land surfac... more ABSTRACT Soils with subsoil clay accumulation account for more than 20% of the global land surface. These soils are characterized by vertical differences with respect to soil texture and increasing bulk density below the topsoil, which in turn affects root penetration into the subsoil. Biopores are preferential pathways for roots and assist in overcoming physical barriers like high density soil layers. An integration of these relationships into cropping systems models at the field scale is on-going. This paper presents a new approach to model the effect of biopores on root development in soils with clay accumulation at the plot scale. In this approach, the effect of biopores on root elongation rate depends on bulk density and on a biopore-root growth threshold (MPRT), which is the biopore volume at which the resistance of soil strength to root penetration is completely offset by the density of the biopores. The approach was integrated into a model solution of the model framework SIMPLACE (Scientific Impact assessment and Modeling PLatform for Advanced Crop and Ecosystem management). MPRT was parameterized for spring wheat using the inverse modeling approach based on root observations from a multi-factorial field experiment on a Haplic Luvisol. The observed biopore densities (>2 mm diameter) were between 300 and 660 pores m−2 (equivalent to a volumetric proportion of 0.38–0.83%) depending on the preceding crop. Observed soil bulk densities ranged between 1.31 and 1.62 g cm−3. For spring wheat, the best fit between simulated and observed root densities in different layers was obtained with a MPRT of 0.023 m3 m−3 (equivalent to 2.3% of soil volume). The mean simulated total above ground biomass was sensitive to MPRT and had the best agreement with observed values when a MPRT between 0.023 and 0.032 m3 m−3 was used in the simulations. Scenario simulations with the parameterized model at the same site demonstrate the importance of biopores for biomass production of short-cycle spring wheat when prolonged dry spells occur. The simulations allow a rough quantification of the biopore effects with respect to root elongation rate and biomass production at the plot scale with the potential to be extended to the field scale.
Adaptation of crops to climate change has to be addressed locally due to the variability of soil,... more Adaptation of crops to climate change has to be addressed locally due to the variability of soil, climate and the specific socio-economic settings influencing farm management decisions. Adaptation of rainfed cropping systems in the Mediterranean is especially challenging due to the projected decline in precipitation in the coming decades, which will increase the risk of droughts. Methods that can help explore uncertainties in climate projections and crop modelling, such as impact response surfaces (IRSs) and ensemble modelling, can then be valuable for identifying effective adaptations. Here, an ensemble of 17 crop models was used to simulate a total of 54 adaptation options for rainfed winter wheat (Triticum aestivum) at Lleida (NE Spain). To support the ensemble building, an ex post quality check of model simulations based on several criteria was performed. Those criteria were based on the “According to Our Current Knowledge” (AOCK) concept, which has been formalized here. Adaptat...
Page 1. Tropentag, October 7-9, 2008, Hohenheim Competition for Resources in a Changing World: N... more Page 1. Tropentag, October 7-9, 2008, Hohenheim Competition for Resources in a Changing World: New Drive for Rural Development Partitioning Pattern and Biomass Production of Yam (Dioscorea rotundata) Amit Kumar Srivastava, Thomas Gaiser ...
Purpose. The addition of cetuximab to radiochemotherapy (RCT) failed to improve complete response... more Purpose. The addition of cetuximab to radiochemotherapy (RCT) failed to improve complete response rates in locally advanced rectal cancer (LARC). We report the long-term results in patients treated within two sequential clinical trials. Methods. Patients receiving neoadjuvant RCT using capecitabine and irinotecan (CapIri) within a phase I/II trial or CapIri + cetuximab within a phase II trial were evaluated for analysis of disease-free survival (DFS) and overall survival (OS). KRAS exon 2 mutational status had been analyzed in patients receiving cetuximab. Results. 37 patients from the CapIri trial and 49 patients from the CapIricetuximab treatment group were evaluable. Median follow-up time was 75.2 months. The 5-year DFS rate was 82% (CapIri) and 79% (CapIri-cetuximab) ( = 0.62). The median OS was 127.4 months. 5-year OS was 73% for both groups (CapIri and CapIricetuximab) ( = 0.61). No significant difference in DFS ( = 0.86) or OS ( = 0.39) was noticed between patients receiving CapIri and those receiving CapIri-cetuximab with KRAS wild-type tumors. Conclusions. As the addition of cetuximab did not improve neither DFS nor OS it should not play a role in the perioperative treatment of patients with LARC, not even of patients with (K)RAS WT tumors.
Verhandlungen der Deutschen Gesellschaft für Pathologie, 2006
Cytotoxic luteinizing hormone releasing hormone (LHRH) analogues AN-152 and AN-207 consist of [D-... more Cytotoxic luteinizing hormone releasing hormone (LHRH) analogues AN-152 and AN-207 consist of [D-Lys6] LHRH linked to doxorubicin or its hyperactive derivate AN-201 and bind with high affinity to LHRH receptors. We evaluated the use of AN-207 and AN-201 in a nude mice model. In order to provide a rationale for the possible use of cytotoxic LHRH analogues in different malignancies we investigated the expression of LHRH-R in human renal cell carcinoma (RCC), melanoma and non Hodgkin's Lymphoma (NHL). The expression of LHRH-R was examined in surgically removed human specimens of primary tumours and metastases from 37 RCC, 19 melanomas and 17 NHLs. In addition, human tumour cell lines expressing LHRH receptors were transplanted into nude mice and anti-tumour efficacy and systemic toxicity of AN-207 and its cytotoxic radical AN-201 were compared in various experiments. Positive staining for LHRH receptors was found in all of the RCC (37/37) and the melanoma specimens (19/19) as well ...
Celecoxib is a cyclooxygenase 2-selective nonsteroidal anti-inflammatory drug (NSAID) that exhibi... more Celecoxib is a cyclooxygenase 2-selective nonsteroidal anti-inflammatory drug (NSAID) that exhibited therapeutic activity in cancer. In this study three malignant glioma, U87-MG, U251 and A172, were treated with celecoxib, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) or the combination of both. Single treatment with celecoxib (25-100muM) for 24h resulted in a concentration-dependant decrease of cellular viability in U87-MG, U251 and A172. Combining subtoxic concentrations of celecoxib with TRAIL strongly increased cell death in human malignant glioma cells. After 8h treatment with celecoxib we found down-regulation of the inhibitor of apoptosis protein survivin that was mediated by proteasomal degradation. In addition, over-expression of survivin not only attenuated celecoxib-induced cytotoxicity but also cytotoxicity induced by the combination of celecoxib and TRAIL. Taken together, in malignant glioma survivin is a key regulator in celecoxib- and TRAIL-celecoxib...
Der Hautarzt; Zeitschrift für Dermatologie, Venerologie, und verwandte Gebiete, 2008
Sinus histiocytosis with massive lymphadenopathy (SHML) is a rare, painless lymphoproliferative d... more Sinus histiocytosis with massive lymphadenopathy (SHML) is a rare, painless lymphoproliferative disorder of unknown origin with a usually benign course. About 40% of the patients show an extranodal involvement with skin being the most common site in 27% of these patients. We describe a patient with widespread disease involving the respiratory tract, kidneys and skin. Histopathology revealed the characteristic features of SHML with emperipolesis and immunohistochemical positivity of histiocytes for S100 and macrophage-associated antigens.
Two cases of symptomatic proctitis with rectal tumors suspicious for malignancy are presented. A ... more Two cases of symptomatic proctitis with rectal tumors suspicious for malignancy are presented. A florid regenerative proctitis was shown in the histological examination. In both cases a sexually transmitted infection (STI) was causing the symptoms. In rare cases STIs present as pseudo tumors mimicking malignancy in clinical examination and endoscopic/radiological analysis. A close collaboration between gastroenterologist and pathologist is necessary for a correct diagnosis and to prevent unnecessary surgical treatment.
Do maize crop models catch the impact of future [CO2] on maize yield and water use?. iCROPM2016 I... more Do maize crop models catch the impact of future [CO2] on maize yield and water use?. iCROPM2016 International Crop Modelling Symposium
ABSTRACT Soils with subsoil clay accumulation account for more than 20% of the global land surfac... more ABSTRACT Soils with subsoil clay accumulation account for more than 20% of the global land surface. These soils are characterized by vertical differences with respect to soil texture and increasing bulk density below the topsoil, which in turn affects root penetration into the subsoil. Biopores are preferential pathways for roots and assist in overcoming physical barriers like high density soil layers. An integration of these relationships into cropping systems models at the field scale is on-going. This paper presents a new approach to model the effect of biopores on root development in soils with clay accumulation at the plot scale. In this approach, the effect of biopores on root elongation rate depends on bulk density and on a biopore-root growth threshold (MPRT), which is the biopore volume at which the resistance of soil strength to root penetration is completely offset by the density of the biopores. The approach was integrated into a model solution of the model framework SIMPLACE (Scientific Impact assessment and Modeling PLatform for Advanced Crop and Ecosystem management). MPRT was parameterized for spring wheat using the inverse modeling approach based on root observations from a multi-factorial field experiment on a Haplic Luvisol. The observed biopore densities (>2 mm diameter) were between 300 and 660 pores m−2 (equivalent to a volumetric proportion of 0.38–0.83%) depending on the preceding crop. Observed soil bulk densities ranged between 1.31 and 1.62 g cm−3. For spring wheat, the best fit between simulated and observed root densities in different layers was obtained with a MPRT of 0.023 m3 m−3 (equivalent to 2.3% of soil volume). The mean simulated total above ground biomass was sensitive to MPRT and had the best agreement with observed values when a MPRT between 0.023 and 0.032 m3 m−3 was used in the simulations. Scenario simulations with the parameterized model at the same site demonstrate the importance of biopores for biomass production of short-cycle spring wheat when prolonged dry spells occur. The simulations allow a rough quantification of the biopore effects with respect to root elongation rate and biomass production at the plot scale with the potential to be extended to the field scale.
Adaptation of crops to climate change has to be addressed locally due to the variability of soil,... more Adaptation of crops to climate change has to be addressed locally due to the variability of soil, climate and the specific socio-economic settings influencing farm management decisions. Adaptation of rainfed cropping systems in the Mediterranean is especially challenging due to the projected decline in precipitation in the coming decades, which will increase the risk of droughts. Methods that can help explore uncertainties in climate projections and crop modelling, such as impact response surfaces (IRSs) and ensemble modelling, can then be valuable for identifying effective adaptations. Here, an ensemble of 17 crop models was used to simulate a total of 54 adaptation options for rainfed winter wheat (Triticum aestivum) at Lleida (NE Spain). To support the ensemble building, an ex post quality check of model simulations based on several criteria was performed. Those criteria were based on the “According to Our Current Knowledge” (AOCK) concept, which has been formalized here. Adaptat...
Page 1. Tropentag, October 7-9, 2008, Hohenheim Competition for Resources in a Changing World: N... more Page 1. Tropentag, October 7-9, 2008, Hohenheim Competition for Resources in a Changing World: New Drive for Rural Development Partitioning Pattern and Biomass Production of Yam (Dioscorea rotundata) Amit Kumar Srivastava, Thomas Gaiser ...
Purpose. The addition of cetuximab to radiochemotherapy (RCT) failed to improve complete response... more Purpose. The addition of cetuximab to radiochemotherapy (RCT) failed to improve complete response rates in locally advanced rectal cancer (LARC). We report the long-term results in patients treated within two sequential clinical trials. Methods. Patients receiving neoadjuvant RCT using capecitabine and irinotecan (CapIri) within a phase I/II trial or CapIri + cetuximab within a phase II trial were evaluated for analysis of disease-free survival (DFS) and overall survival (OS). KRAS exon 2 mutational status had been analyzed in patients receiving cetuximab. Results. 37 patients from the CapIri trial and 49 patients from the CapIricetuximab treatment group were evaluable. Median follow-up time was 75.2 months. The 5-year DFS rate was 82% (CapIri) and 79% (CapIri-cetuximab) ( = 0.62). The median OS was 127.4 months. 5-year OS was 73% for both groups (CapIri and CapIricetuximab) ( = 0.61). No significant difference in DFS ( = 0.86) or OS ( = 0.39) was noticed between patients receiving CapIri and those receiving CapIri-cetuximab with KRAS wild-type tumors. Conclusions. As the addition of cetuximab did not improve neither DFS nor OS it should not play a role in the perioperative treatment of patients with LARC, not even of patients with (K)RAS WT tumors.
Verhandlungen der Deutschen Gesellschaft für Pathologie, 2006
Cytotoxic luteinizing hormone releasing hormone (LHRH) analogues AN-152 and AN-207 consist of [D-... more Cytotoxic luteinizing hormone releasing hormone (LHRH) analogues AN-152 and AN-207 consist of [D-Lys6] LHRH linked to doxorubicin or its hyperactive derivate AN-201 and bind with high affinity to LHRH receptors. We evaluated the use of AN-207 and AN-201 in a nude mice model. In order to provide a rationale for the possible use of cytotoxic LHRH analogues in different malignancies we investigated the expression of LHRH-R in human renal cell carcinoma (RCC), melanoma and non Hodgkin's Lymphoma (NHL). The expression of LHRH-R was examined in surgically removed human specimens of primary tumours and metastases from 37 RCC, 19 melanomas and 17 NHLs. In addition, human tumour cell lines expressing LHRH receptors were transplanted into nude mice and anti-tumour efficacy and systemic toxicity of AN-207 and its cytotoxic radical AN-201 were compared in various experiments. Positive staining for LHRH receptors was found in all of the RCC (37/37) and the melanoma specimens (19/19) as well ...
Celecoxib is a cyclooxygenase 2-selective nonsteroidal anti-inflammatory drug (NSAID) that exhibi... more Celecoxib is a cyclooxygenase 2-selective nonsteroidal anti-inflammatory drug (NSAID) that exhibited therapeutic activity in cancer. In this study three malignant glioma, U87-MG, U251 and A172, were treated with celecoxib, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) or the combination of both. Single treatment with celecoxib (25-100muM) for 24h resulted in a concentration-dependant decrease of cellular viability in U87-MG, U251 and A172. Combining subtoxic concentrations of celecoxib with TRAIL strongly increased cell death in human malignant glioma cells. After 8h treatment with celecoxib we found down-regulation of the inhibitor of apoptosis protein survivin that was mediated by proteasomal degradation. In addition, over-expression of survivin not only attenuated celecoxib-induced cytotoxicity but also cytotoxicity induced by the combination of celecoxib and TRAIL. Taken together, in malignant glioma survivin is a key regulator in celecoxib- and TRAIL-celecoxib...
Der Hautarzt; Zeitschrift für Dermatologie, Venerologie, und verwandte Gebiete, 2008
Sinus histiocytosis with massive lymphadenopathy (SHML) is a rare, painless lymphoproliferative d... more Sinus histiocytosis with massive lymphadenopathy (SHML) is a rare, painless lymphoproliferative disorder of unknown origin with a usually benign course. About 40% of the patients show an extranodal involvement with skin being the most common site in 27% of these patients. We describe a patient with widespread disease involving the respiratory tract, kidneys and skin. Histopathology revealed the characteristic features of SHML with emperipolesis and immunohistochemical positivity of histiocytes for S100 and macrophage-associated antigens.
Two cases of symptomatic proctitis with rectal tumors suspicious for malignancy are presented. A ... more Two cases of symptomatic proctitis with rectal tumors suspicious for malignancy are presented. A florid regenerative proctitis was shown in the histological examination. In both cases a sexually transmitted infection (STI) was causing the symptoms. In rare cases STIs present as pseudo tumors mimicking malignancy in clinical examination and endoscopic/radiological analysis. A close collaboration between gastroenterologist and pathologist is necessary for a correct diagnosis and to prevent unnecessary surgical treatment.
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Papers by T. Gaiser