562 research outputs found

    The preparation and properties of lanthanum-promoted nickel-alumina catalysts:Structure of the precipitates

    Get PDF
    Precursors of La-promoted Ni-alumina catalysts have been prepared by precipitation from their nitrate solutions at pH 7 using solutions of NH4HCO3, Na2CO3 or K2CO3. The preparation was carried out either by coprecipitation from a mixed salt solution or by sequential precipitation of Al3+, La3+ and Ni2+ in succession. In the absence of promoter, the precipitate with Ni/Al ratio of 2.5 is of the pyroaurite structure and has the composition Ni5Al2(OH)14CO3.4H2O. Two types of lanthanum-containing precipitate were made in which either extra La was added (Ni/Al kept constant at 2.5) or the proportion Ni/(Al+La) was kept constant at 2.5. The majority of these precipitates were single compounds which also had the pyroaurite structure. At high La contents, the series in which La is added gives separation of the compounds La2O(CO3)2 and LaONO3 in addition to the layer structure; with the series in which the La is substituted for Al, all the samples appeared to have the pyroaurite structure, even one in which no Al was present. The sequential precipitation route yields smaller crystallites than does coprecipitation. Materials precipitated with NH4HCO3 in all cases contained NH4NO3 while those precipitated with Na2CO3 gave inclusion of NaNO3. In both cases, the presence of the nitrates causes a decrease of crystallinity of the layer compound. Potassium is not included in the precipitate in any of the samples examined. A model is presented for the structure of the lanthanum-containing precipitates

    Cerebrospinal fluid and serum MHPG improve Alzheimer's disease versus dementia with Lewy bodies differential diagnosis

    Get PDF
    Introduction: Given the challenges concerning the differential diagnosis of dementia, we investigated the possible added value of monoaminergic compounds to the standard cerebrospinal fluid (CSF) Alzheimer's disease (AD) biomarkers. Particularly, regarding the AD versus dementia with Lewy bodies (DLB) comparison, monoamines or their metabolites might have added discriminative value as there is a more severe neuropathological burden in the locus coeruleus of DLB patients, the principal site of noradrenaline synthesis. Methods: We applied enzyme-linked immunosorbent assay (ELISA) to analyze CSF amyloid β peptide of 42 amino acids, total tau, and tau phosphorylated at threonine 181, in patients with AD, frontotemporal dementia, DLB/Parkinson's disease dementia, and controls. Reversed-phase high-performance liquid chromatography with electrochemical detection was implemented to study monoamine and metabolite levels in CSF and serum. Stepwise forward conditional logistic regression and receiver operating characteristic (ROC) curve analyses were performed to assess the diagnostic accuracy of these newly fitted models containing the most discriminative indicators of disease status. Results: Most significant differences in CSF and serum were confined to the noradrenergic system. More specifically, CSF 3-methoxy-4-hydroxyphenylglycol (MHPG) levels were higher, whereas serum MHPG levels were lower, in DLB patients compared with all other groups. Addition of CSF and serum MHPG levels to the CSF AD biomarker panel significantly increased diagnostic accuracy between DLB/Parkinson's disease dementia and AD. Interestingly, a model only including CSF and serum MHPG without the classic AD biomarker panel reached similar area under the curve values. Discussion: We hypothesize that varying degrees of neuronal loss in the locus coeruleus of DLB/Parkinson's disease dementia versus AD patients result in differentially altered MHPG levels, making this metabolite a valuable biomarker

    Cerebrospinal fluid P-tau(181P):biomarker for improved differential dementia diagnosis

    Get PDF
    The goal of this study is to investigate the value of tau phosphorylated at threonine 181 (P-tau(181p)) in the Alzheimer's disease (AD) cerebrospinal fluid (CSF) biomarker panel for differential dementia diagnosis in autopsy confirmed AD and non-AD patients. The study population consisted of 140 autopsy confirmed AD and 77 autopsy confirmed non-AD dementia patients. CSF concentrations of amyloid-beta peptide of 42 amino acids (A(beta 1-42)), total tau protein (T-tau), and P-tau(181p) were determined with single analyte ELISA-kits (INNOTEST, Fujirebio, Ghent, Belgium). Diagnostic accuracy was assessed through receiver operating characteristic (ROC) curve analyses to obtain area under the curve (AUG) values and to define optimal cutoff values to discriminate AD from pooled and individual non-AD groups. ROC curve analyses were only performed on biomarkers and ratios that differed significantly between the groups. Pairwise comparison of AUG values was performed by means of DeLong tests. The A(beta 1-42)/P-tau(181p) ratio (AUG = 0.770) performed significantly better than A(beta 1-42) (AUG = 0.677, P = 0.004), T-tau (AUG = 0.592, P <0.001), and A beta(1-42)/T-tau (AUG = 0.678, P = 0.001), while Ptau(181p) (AUG = 0.720) performed significantly better than T-tau (AUG = 0.592, P <0.001) to discriminate between AD and the pooled non-AD group. When comparing AD and the individual non-AD diagnoses, A beta(1-42)/P-tau(181P) (AUG =0.894) discriminated AD from frontotemporal dementia significantly better than A(beta 1-42) (AUG = 0.776, P = 0.020) and T-tau (AUG = 0.746, P = 0.004), while P-tauisip/T-tau (AUG = 0.958) significantly improved the differentiation between AD and Creutzfeldt-Jakob disease as compared to A beta(1-42) (AUG = 0.688, P = 0.004), T-tau (AUG = 0.874, P = 0.040), and A beta(1-42)/P-tau(181P) (AUG = 0.760, P = 0.003). In conclusion, this study demonstrates P-tau(181P) P is an essential component of the AD CSF biomarker panel, and combined assessment of A beta(1-42), Ttau, and P-tau(181p) renders, to present date, the highest diagnostic power to discriminate between AD and non-AD dementias

    Depression in Mild Cognitive Impairment is associated with Progression to Alzheimer's Disease:A Longitudinal Study

    Get PDF
    Background: Behavioral and psychological signs and symptoms of dementia (BPSD) belong to the core symptoms of dementia and are also common in mild cognitive impairment (MCI).Objective: This study would like to contribute to the understanding of the prognostic role of BPSD in MCI for the progression to dementia due to Alzheimer's disease (AD).Methods: Data were generated through an ongoing prospective longitudinal study on BPSD. Assessment was performed by means of the Middelheim Frontality Score, Behave-AD, Cohen-Mansfield Agitation Inventory, Cornell Scale for Depression in Dementia (CSDD), and Geriatric Depression Scale 30-questions (GDS-30). Cox proportional hazard models were used to test the hypothesis that certain BPSD in MCI are predictors of developing AD.Results: The study population consisted of 183 MCI patients at baseline. At follow-up, 74 patients were stable and 109 patients progressed to AD. The presence of significant depressive symptoms in MCI as measured by the CSDD (HR: 2.06; 95% CI: 1.23-3.44; p = 0.011) and the GDS-30 (HR: 1.77; 95% CI: 1.10-2.85; p = 0.025) were associated with progression to AD. The severity of depressive symptoms as measured by the GDS-30 was a predictor for progression too (HR: 1.06; 95% CI: 1.01-1.11; p = 0.020). Furthermore, the severity of agitated behavior, especially verbal agitation and the presence of purposeless activity, was also associated with progression, whereas diurnal rhythm disturbances were associated with no progression to AD.Conclusion: Depressive symptoms in MCI appear to be predictors for progression to AD.</p

    Effect of feed ingredients on nutrient digestibility, waste production and physical characteristics of rainbow trout (Oncorhynchus mykiss) faeces.

    Get PDF
    This study assessed the effect of different dietary ingredients on the quantity and characteristics of faecal waste produced by rainbow trout (Oncorhynchus mykiss). Seven ingredients were tested: fish meal (FM), mussel meal (MM), poultry meal wet rendered (PM-W) or dry rendered (PM-D), insect meal (IM), single cell protein (SCP) and brewers grain protein (BGP). Eight experimental diets were formulated: a control diet (CON) being predominantly plant-based and seven test diets, which contained 70% of the CON diet and 30% of one of the test ingredients. Rainbow trout juveniles (65 g, 30 fish/tank) were fed the experimental diets at satiation for six weeks in triplicate groups. Dry matter (DM) and nutrient digestibility of diets and the test ingredients were measured. To estimate the faecal characteristics, particle size distribution (PSD) and removal efficiency of the faecal waste was determined. Nutrient digestibility of diets and ingredients differed significantly. Growth did not differ between the experimental diets, but DM digestibility was affected by the diet. Diets affected the amount of faecal waste produced, its removal efficiency (%) and the amount of non-removed faeces (g DM/kg DM feed). The highest and lowest removal efficiency was observed at FM and BGP diets, respectively. Accordingly, FM diet resulted in the lowest (37 g DM/kg DM feed), while BGP diet resulted in the highest (125 g DM/kg DM feed) amount of non-removed faeces. Additionally, it was also observed that differences in faecal removal efficiency can compensate for the variation in the quantity of faecal waste produced. Consistent with the faecal removal efficiency data, faeces PSD was also influenced by diets. FM and MM diets resulted in faeces with the lowest proportion of particles of <40 ÎĽm size, while BGP diet had the largest proportion of faecal particles of this size range. Furthermore, the effect of dietary ingredient composition was evident in the stability of faeces, with FM producing the most stable, whereas CON, BGP and SCP diets resulting in relatively unstable faecal pellets. In addition, due to differences in inclusion level of nutrients and their corresponding digestibility, the chemical composition of faeces differed between the diets. Overall, the study showed that dietary ingredient composition influences nutrient digestibility and is an important factor determining the amount of faecal waste produced, its removal efficiency, PSD, stability and composition in rainbow trout.publishedVersio

    Predicting advertising effectiveness by facial expressions in response to amusing persuasive stimuli.

    Get PDF
    We present a psychophysiological study of facial expressions of happiness (FEH) produced by advertisements using the FaceReader system (Noldus, 2013) for automatic analysis of facial expressions of basic emotions (FEBE; Ekman, 1972). FaceReader scores were associated with self-reports of the advertisement’s effectiveness. Building on work describing the role of emotions in marketing research, we examined the relationship between the patterns of the FEBE and the perceived amusement of the advertisements, attitude toward the advertisement (AAD) and attitude toward the brand (AB). Differences were observed between FEH scores in response to high-, medium-, and low-amusing video advertisements (AVAs). Positive correlations were found between FEH and AAD and FEH and AB in high- and medium- but not in low-AVAs. As hypothesized, other basic emotions (sadness, anger, surprise, fear, and disgust) did not predict advertisement amusement or advertisements’ effectiveness. FaceReader enabled a detailed analysis of more than 120,000 frames of video-recordings contributing to an identification of global patterns of facial reactions to amusing persuasive stimuli. For amusing commercials, context-specific FEH features were found to be the major indicators of advertisement effectiveness. The study used video-recordings of participants in their natural environments obtained through a crowd-sourcing platform. The naturalistic design of the study strengthened its ecological validity and demonstrated the robustness of the software algorithms even under austere conditions. Our findings provide first evidence for the applicability of FaceReader methodology in the basic consumer science research
    • …
    corecore