Comparaison de differentes methodes de dosage des nitrates dans les extraits de sols. Influence du milieu d'extraction

Une comparaison de quatre méthodes de dosage des nitrates a été faite dans des extraits de quarante sols : la détermination directe à l’aide d’une électrode sélective, la méthode DEVARDA et deux méthodes automatiques basées sur la réduction des nitrates en nitrites, l’une par un mélange sulfate de cuivre-sulfate d’hydrazine, l’autre par une colonne de cadmium cuivré, et la colorimétrie des nitrites obtenus. L’influence du milieu d’extraction (KCl 2 N, Ca2Cl2 0,01 N et CuSO4 0,002 N) sur les dosages de nitrates a été étudiée. Il a été vérifié qu’elle est nulle pour les dosages par la méthode DEVARDA et importante pour les autres méthodes. Les méthodes colorimétriques automatiques ont donné des résultats satisfaisants dans l’extrait KCl 2 N. Dans les extraits CaCl2 0,01 N et CuSO4 0,02 N, nous avons constaté des interférences liées à la présence des ions calciques et cuivriques. Cependant, à l’exception de la méthode à l’hydrazine dans l’extrait CuS04, les erreurs provoquées sont faibles pour les sols que nous avons étudiés et ces milieux semblent donc utilisables. Pour les dosages potentiométriques, nous avons constaté des interférences importantes qui peuvent être éliminées totalement dans l’extrait CaCl2 0,01 N par abaissement du pH à 4,5 par de l’acide sulfurique. Cette précaution n’est pas nécessaire pour tous les modèles d’électrode de mesure entre lesquels d’importantes différences de sélectivité sont mises en évidence. Dans les extraits CuSO4 0,02 N, après abaissement du pH à 4,5, il subsiste une erreur dont nous n’expliquons pas l’origine.Four nitrate determination methods were compared for 40 soil extracts : the DEVARDA method, potentiometry and two automatised colorimetric methods reducing nitrates to nitrites, either by a mixture of copper Cadmium, sulfate and hydrazine sulfate or by a copperized cadmium column. Interactions with the extraction medium (2 N KCI, 0.01 N CaCl2 and 0.02 N CuSO4) were studied. They did not influence results by the DEVARDA method but were of particular importance for potentiometry and automatic reduction to nitrites. With autoanalysers, the best results, apparently free from interference, were obtained in the KCl extracts. Significant interference due to calcium and copper ions was established for the other two extraction media. However, except for the hydrazine method applied to CuSO4 extracts, the differences from the DEVARDA values were small and these extracts appear to be suitable for nitrate determinations by automatic reduction to nitrite. Potentiometric determinations were subject to severe interference, but this could be eliminated in CaCl2 extracts by lowering the pH to 4.5 with sulfuric acid. However this is not necessary for all electrode models, since these differ greatly in specificity. Lowering the pH to 4.5 in the CuSO4 extracts did not eliminate interference completely and significant differences from the DEVARDA method remained

Utilisation agricole de quelques déchets de distilleries de vins rouges

International audienc

Comparaison de différentes méthodes de dosage des nitrates dans les extraits de sol. Influence du milieu d'extraction

Four nitrate determination methods were compared for 40 soil extracts: the DEVARDA method, potentiometry and two automized colorimetric methods reducing nitrate to nitrite, either by a mixture of copper sulfate and hydrazine sulfate or by a copperized cadmium column. Interactions with the extraction medium (2 N KCl, 0.01 N CaCl2 and 0.02 N CuSO4) were studied. They did not influence results by the DEVARDA method but were of particular importance for potentiometry and automatic reduction to nitrite. With autoanalysers, the best results, apparently free from interference, were obtained in the KCl extracts. Significant interference due to calcium and copper ions was established for the other two extraction media. However, except for the hydrazine method applied to CuSO4 extracts, the differences from the DEVARDA values were small and these extracts appear to be suitable for nitrate determinations by automatic reduction to nitrite. Potentiometric determinations were subject to severe interference, but this could be eliminated in CaCl2 extracts by lowering the pH to 4.5 with sulfuric acid. However this is not necessary for all electrode models, since these differ greatly in specificity. Lowering the pH to 4.5 in the CuSO4 extracts did not eliminate interference completely and significant differences from the DEVARDA method remained.Une comparaison de quatre méthodes de dosage des nitrates a été faite dans des extraits de quarante sols : la détermination directe à l’aide d’une électrode sélective, la méthode E DVARDA et deux méthodes automatiques basées sur la réduction des nitrates en nitrites, l’une par un mélange sulfate de cuivre-sulfate d’hydrazine,l’autre par une colonne de cadmium cuivré, et la colorimétrie des nitrites obtenus.L’influence du milieu d’extraction (KCI2 2 N, C 2aC’ 0,01 N et S 4CU00,02 N) sur les dosages de nitrates a été étudiée. Il a été vérifié qu’elle est nulle pour les dosages par la méthode E DVARDA et importante pour les autres méthodes. Les méthodes colorimétriques automatiques ont donné des résultats satisfaisants dans l’extrait KCl 2 N. Dans les extraits C 2aCI 0,01 N et S 4CU00,02 N, nous avons constaté des interférences liées à la présence des ions calciques et cuivriques. Cependant, à l’exception de la méthode à l’hydrazine dans l’extrait S,4CU0 les erreurs provoquées sont faibles pour les sols que nous avons étudiés et ces milieux semblent donc utilisables. Pour les dosages potentiométriques, nous avons constaté des interférences importantes qui peuvent être éliminées totalement dans l’extrait C 2aC’ 0,01 N par abaissement du pH à 4,5 par de l’acide sulfurique. Cette précaution n’est pas nécessaire pour tous les modèles d’électrode de mesure entre lesquels d’importantes différences de sélectivité sont mises en évidence. Dans les extraits S 4CU00,02 N, après abaissement du pH à 4,5, il subsiste une erreur dont nous n’expliquons pas l’origine

Etude de la correlation des teneurs en K, Ca ou Mg entre feuilles et epines de Citrus volkameriana Ten et Pasq

National audienceA search for samples other than leaves, so that the latter remained on young citrus trees under experiment, led to the study of possible link between cationic concentrations in associated leaf and thorn. Citrus volkameriana were grown in a glasshouse on a soilless system with 5 K levels (2, 4, 6, 8 or 10 mmol-(K).|-1). 3 sampling levels were chosen along the plant (fig 1); 6 replicates were available. Potassium concentrations were significantly correlated within each sampling level (fig 2a). Thus, 3 regressions had to be considered, which differed for each location. The effect of the differentiated K supply on leaf K content was measured by comparing K concentrations in thorns sampled within a given level. Calcium and magnesium concentrations were shown to be significantly correlated between associated leaves and thorns when the 3 sampling levels were considered as a whole. Variability was then mainly explained by the distribution gradient along the plant, either due to Ca immobilisation (fig 2b, higher contents in older organs) or Mg redistribution (fig 2c, lower contents in older organs). The Ca and Mg vertical distribution along the plant axis could therefore be characterised by comparing Ca and Mg concentrations of thorns sampled along this axis. The influence of sampling location and differentiated K supplies on observed foliage concentrations are discussed for the 3 cations.La recherche d’organes pouvant être prélevés sur des jeunes plants de Citrus en expérimentation, afin de préserver les feuilles, explique l’intérêt suscité par une éventuelle corrélation entre la composition minérale des feuilles et celle des épines associées. Sur une culture hors-sol de C volkameriana de 6 mois différenciée par la concentration en K de la fertirrigation (2, 4, 6, 8 ou 10 mmol-(K).|-1 on étudie la relation entre les teneurs en K, Ca ou Mg des feuilles et épines. Avec des règles de prélèvement précisées ici, les teneurs des épines sont significativement corrélées à celles des feuilles qu’elles axillent. La différenciation en K de l’appareil végétatif peut ainsi être caractérisée en prélevant des épines, donc en préservant le système foliaire. Par ailleurs, les épines permettent d’évaluer les profils de teneurs en Ca et Mg le long du plant, c’est-à-dire d’étudier leur gradient de répartition verticale

Etude de la correlation des teneurs en K, Ca ou Mg entre feuilles et epines de Citrus volkameriana Ten et Pasq

National audienceA search for samples other than leaves, so that the latter remained on young citrus trees under experiment, led to the study of possible link between cationic concentrations in associated leaf and thorn. Citrus volkameriana were grown in a glasshouse on a soilless system with 5 K levels (2, 4, 6, 8 or 10 mmol-(K).|-1). 3 sampling levels were chosen along the plant (fig 1); 6 replicates were available. Potassium concentrations were significantly correlated within each sampling level (fig 2a). Thus, 3 regressions had to be considered, which differed for each location. The effect of the differentiated K supply on leaf K content was measured by comparing K concentrations in thorns sampled within a given level. Calcium and magnesium concentrations were shown to be significantly correlated between associated leaves and thorns when the 3 sampling levels were considered as a whole. Variability was then mainly explained by the distribution gradient along the plant, either due to Ca immobilisation (fig 2b, higher contents in older organs) or Mg redistribution (fig 2c, lower contents in older organs). The Ca and Mg vertical distribution along the plant axis could therefore be characterised by comparing Ca and Mg concentrations of thorns sampled along this axis. The influence of sampling location and differentiated K supplies on observed foliage concentrations are discussed for the 3 cations.La recherche d’organes pouvant être prélevés sur des jeunes plants de Citrus en expérimentation, afin de préserver les feuilles, explique l’intérêt suscité par une éventuelle corrélation entre la composition minérale des feuilles et celle des épines associées. Sur une culture hors-sol de C volkameriana de 6 mois différenciée par la concentration en K de la fertirrigation (2, 4, 6, 8 ou 10 mmol-(K).|-1 on étudie la relation entre les teneurs en K, Ca ou Mg des feuilles et épines. Avec des règles de prélèvement précisées ici, les teneurs des épines sont significativement corrélées à celles des feuilles qu’elles axillent. La différenciation en K de l’appareil végétatif peut ainsi être caractérisée en prélevant des épines, donc en préservant le système foliaire. Par ailleurs, les épines permettent d’évaluer les profils de teneurs en Ca et Mg le long du plant, c’est-à-dire d’étudier leur gradient de répartition verticale

Etude de la correlation des teneurs en K, Ca ou Mg entre feuilles et epines de Citrus volkameriana Ten et Pasq

La recherche d’organes pouvant être prélevés sur des jeunes plants de Citrus en expérimentation, afin de préserver les feuilles, explique l’intérêt suscité par une éventuelle corrélation entre la composition minérale des feuilles et celle des épines associées. Sur une culture hors-sol de C volkameriana de 6 mois différenciée par la concentration en K de la fertirrigation (2, 4, 6, 8 ou 10 mmol-(K).|-1 on étudie la relation entre les teneurs en K, Ca ou Mg des feuilles et épines. Avec des règles de prélèvement précisées ici, les teneurs des épines sont significativement corrélées à celles des feuilles qu’elles axillent. La différenciation en K de l’appareil végétatif peut ainsi être caractérisée en prélevant des épines, donc en préservant le système foliaire. Par ailleurs, les épines permettent d’évaluer les profils de teneurs en Ca et Mg le long du plant, c’est-à-dire d’étudier leur gradient de répartition verticale.A search for samples other than leaves, so that the latter remained on young citrus trees under experiment, led to the study of possible link between cationic concentrations in associated leaf and thorn. Citrus volkameriana were grown in a glasshouse on a soilless system with 5 K levels (2, 4, 6, 8 or 10 mmol-(K).|-1). 3 sampling levels were chosen along the plant (fig 1); 6 replicates were available. Potassium concentrations were significantly correlated within each sampling level (fig 2a). Thus, 3 regressions had to be considered, which differed for each location. The effect of the differentiated K supply on leaf K content was measured by comparing K concentrations in thorns sampled within a given level. Calcium and magnesium concentrations were shown to be significantly correlated between associated leaves and thorns when the 3 sampling levels were considered as a whole. Variability was then mainly explained by the distribution gradient along the plant, either due to Ca immobilisation (fig 2b, higher contents in older organs) or Mg redistribution (fig 2c, lower contents in older organs). The Ca and Mg vertical distribution along the plant axis could therefore be characterised by comparing Ca and Mg concentrations of thorns sampled along this axis. The influence of sampling location and differentiated K supplies on observed foliage concentrations are discussed for the 3 cations

Understanding Factors Associated With Psychomotor Subtypes of Delirium in Older Inpatients With Dementia

Objectives: Few studies have analyzed factors associated with delirium subtypes. In this study, we investigate factors associated with subtypes of delirium only in patients with dementia to provide insights on the possible prevention and treatments. Design: This is a cross-sectional study nested in the \u201cDelirium Day\u201d study, a nationwide Italian point-prevalence study. Setting and Participants: Older patients admitted to 205 acute and 92 rehabilitation hospital wards. Measures: Delirium was evaluated with the 4-AT and the motor subtypes with the Delirium Motor Subtype Scale. Dementia was defined by the presence of a documented diagnosis in the medical records and/or prescription of acetylcholinesterase inhibitors or memantine prior to admission. Results: Of the 1057 patients with dementia, 35% had delirium, with 25.6% hyperactive, 33.1% hypoactive, 34.5% mixed, and 6.7% nonmotor subtype. There were higher odds of having venous catheters in the hypoactive (OR 1.82, 95% CI 1.18-2.81) and mixed type of delirium (OR 2.23, CI 1.43-3.46), whereas higher odds of urinary catheters in the hypoactive (OR 2.91, CI 1.92-4.39), hyperactive (OR 1.99, CI 1.23-3.21), and mixed types of delirium (OR 2.05, CI 1.36-3.07). We found higher odds of antipsychotics both in the hyperactive (OR 2.87, CI 1.81-4.54) and mixed subtype (OR 1.84, CI 1.24-2.75), whereas higher odds of antibiotics was present only in the mixed subtype (OR 1.91, CI 1.26-2.87). Conclusions and Implications: In patients with dementia, the mixed delirium subtype is the most prevalent followed by the hypoactive, hyperactive, and nonmotor subtype. Motor subtypes of delirium may be triggered by clinical factors, including the use of venous and urinary catheters, and the use of antipsychotics. Future studies are necessary to provide further insights on the possible pathophysiology of delirium in patients with dementia and to address the optimization of the management of potential risk factors

Drug Prescription and Delirium in Older Inpatients: Results From the Nationwide Multicenter Italian Delirium Day 2015-2016

Objective: This study aimed to evaluate the association between polypharmacy and delirium, the association of specific drug categories with delirium, and the differences in drug-delirium association between medical and surgical units and according to dementia diagnosis. Methods: Data were collected during 2 waves of Delirium Day, a multicenter delirium prevalence study including patients (aged 65 years or older) admitted to acute and long-term care wards in Italy (2015-2016); in this study, only patients enrolled in acute hospital wards were selected (n = 4,133). Delirium was assessed according to score on the 4 "A's" Test. Prescriptions were classified by main drug categories; polypharmacy was defined as a prescription of drugs from 5 or more classes. Results: Of 4,133 participants, 969 (23.4%) had delirium. The general prevalence of polypharmacy was higher in patients with delirium (67.6% vs 63.0%, P =.009) but varied according to clinical settings. After adjustment for confounders, polypharmacy was associated with delirium only in patients admitted to surgical units (OR = 2.9; 95% CI, 1.4-6.1). Insulin, antibiotics, antiepileptics, antipsychotics, and atypical antidepressants were associated with delirium, whereas statins and angiotensin receptor blockers exhibited an inverse association. A stronger association was seen between typical and atypical antipsychotics and delirium in subjects free from dementia compared to individuals with dementia (typical: OR = 4.31; 95% CI, 2.94-6.31 without dementia vs OR = 1.64; 95% CI, 1.19-2.26 with dementia; atypical: OR = 5.32; 95% CI, 3.44-8.22 without dementia vs OR = 1.74; 95% CI, 1.26-2.40 with dementia). The absence of antipsychotics among the prescribed drugs was inversely associated with delirium in the whole sample and in both of the hospital settings, but only in patients without dementia. Conclusions: Polypharmacy is significantly associated with delirium only in surgical units, raising the issue of the relevance of medication review in different clinical settings. Specific drug classes are associated with delirium depending on the clinical setting and dementia diagnosis, suggesting the need to further explore this relationship