5 results
Spectroscopic studies of kaolin from different Brazilian regions
- R. B. Scorzelli, L. C. Bertolino, A. B. Luz, M. Duttine, F. A. N. G. Silva, P. Munayco
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- Journal:
- Clay Minerals / Volume 43 / Issue 1 / March 2008
- Published online by Cambridge University Press:
- 09 July 2018, pp. 129-135
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Over the past several decades, kaolin has been used intensively in the paper industry as a coating and filler material. These applications require kaolin of a high brightness grade, which depends heavily on the level of impurities (mainly Fe-bearing minerals such as Fe oxides and hydroxides) and may be improved by beneficiation processes involving grain-size classification, magnetic separation and chemical treatments. This investigation was carried out on five Brazilian kaolin samples of different geographical and geological origins. Granulometric, mineralogical, chemical and physical characterizations were performed on all samples before and after the beneficiation process.
Chemical compositions were determined by X-ray fluorescence and the most important crystalline phases were identified using X-ray diffraction. Kaolinite is the dominant mineralogical phase with minor amounts of muscovite and quartz. The nature of Fe impurities was investigated by electron spin resonance and 57Fe Mössbauer spectroscopy. For all studied kaolin samples, Fe ions (Fe3+ and Fe2+) are present in variable amounts, in the kaolinite structure and also in Fe oxides (magnetite, hematite and goethite). The beneficiation procedure aims to remove these Fe oxides and was found to be most efficient for the Mogi das Cruzes kaolin. The Seridó kaolin had the best whiteness index observed among the analysed samples.
Familial aggregation of MATRICS Consensus Cognitive Battery scores in a large sample of outpatients with schizophrenia and their unaffected relatives
- A. Mucci, S. Galderisi, M. F. Green, K. Nuechterlein, P. Rucci, D. Gibertoni, A. Rossi, P. Rocca, A. Bertolino, P. Bucci, G. Hellemann, M. Spisto, D. Palumbo, E. Aguglia, G. Amodeo, M. Amore, A. Bellomo, R. Brugnoli, B. Carpiniello, L. Dell'Osso, F. Di Fabio, M. di Giannantonio, G. Di Lorenzo, C. Marchesi, P. Monteleone, C. Montemagni, L. Oldani, R. Romano, R. Roncone, P. Stratta, E. Tenconi, A. Vita, P. Zeppegno, M. Maj, Italian Network for Research on Psychoses
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- Journal:
- Psychological Medicine / Volume 48 / Issue 8 / June 2018
- Published online by Cambridge University Press:
- 11 October 2017, pp. 1359-1366
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Background
The increased use of the MATRICS Consensus Cognitive Battery (MCCB) to investigate cognitive dysfunctions in schizophrenia fostered interest in its sensitivity in the context of family studies. As various measures of the same cognitive domains may have different power to distinguish between unaffected relatives of patients and controls, the relative sensitivity of MCCB tests for relative–control differences has to be established. We compared MCCB scores of 852 outpatients with schizophrenia (SCZ) with those of 342 unaffected relatives (REL) and a normative Italian sample of 774 healthy subjects (HCS). We examined familial aggregation of cognitive impairment by investigating within-family prediction of MCCB scores based on probands’ scores.
MethodsMultivariate analysis of variance was used to analyze group differences in adjusted MCCB scores. Weighted least-squares analysis was used to investigate whether probands’ MCCB scores predicted REL neurocognitive performance.
ResultsSCZ were significantly impaired on all MCCB domains. REL had intermediate scores between SCZ and HCS, showing a similar pattern of impairment, except for social cognition. Proband's scores significantly predicted REL MCCB scores on all domains except for visual learning.
ConclusionsIn a large sample of stable patients with schizophrenia, living in the community, and in their unaffected relatives, MCCB demonstrated sensitivity to cognitive deficits in both groups. Our findings of significant within-family prediction of MCCB scores might reflect disease-related genetic or environmental factors.
Prefrontal cortical thinning links to negative symptoms in schizophrenia via the ENIGMA consortium
- E. Walton, D. P. Hibar, T. G. M. van Erp, S. G. Potkin, R. Roiz-Santiañez, B. Crespo-Facorro, P. Suarez-Pinilla, N. E. M. van Haren, S. M. C. de Zwarte, R. S. Kahn, W. Cahn, N. T. Doan, K. N. Jørgensen, T. P. Gurholt, I. Agartz, O. A. Andreassen, L. T. Westlye, I. Melle, A. O. Berg, L. Morch-Johnsen, A. Færden, L. Flyckt, H. Fatouros-Bergman, Karolinska Schizophrenia Project Consortium (KaSP), E. G. Jönsson, R. Hashimoto, H. Yamamori, M. Fukunaga, N. Jahanshad, P. De Rossi, F. Piras, N. Banaj, G. Spalletta, R. E. Gur, R. C. Gur, D. H. Wolf, T. D. Satterthwaite, L. M. Beard, I. E. Sommer, S. Koops, O. Gruber, A. Richter, B. Krämer, S. Kelly, G. Donohoe, C. McDonald, D. M. Cannon, A. Corvin, M. Gill, A. Di Giorgio, A. Bertolino, S. Lawrie, T. Nickson, H. C. Whalley, E. Neilson, V. D. Calhoun, P. M. Thompson, J. A. Turner, S. Ehrlich
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- Journal:
- Psychological Medicine / Volume 48 / Issue 1 / January 2018
- Published online by Cambridge University Press:
- 26 May 2017, pp. 82-94
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Background
Our understanding of the complex relationship between schizophrenia symptomatology and etiological factors can be improved by studying brain-based correlates of schizophrenia. Research showed that impairments in value processing and executive functioning, which have been associated with prefrontal brain areas [particularly the medial orbitofrontal cortex (MOFC)], are linked to negative symptoms. Here we tested the hypothesis that MOFC thickness is associated with negative symptom severity.
MethodsThis study included 1985 individuals with schizophrenia from 17 research groups around the world contributing to the ENIGMA Schizophrenia Working Group. Cortical thickness values were obtained from T1-weighted structural brain scans using FreeSurfer. A meta-analysis across sites was conducted over effect sizes from a model predicting cortical thickness by negative symptom score (harmonized Scale for the Assessment of Negative Symptoms or Positive and Negative Syndrome Scale scores).
ResultsMeta-analytical results showed that left, but not right, MOFC thickness was significantly associated with negative symptom severity (βstd = −0.075; p = 0.019) after accounting for age, gender, and site. This effect remained significant (p = 0.036) in a model including overall illness severity. Covarying for duration of illness, age of onset, antipsychotic medication or handedness weakened the association of negative symptoms with left MOFC thickness. As part of a secondary analysis including 10 other prefrontal regions further associations in the left lateral orbitofrontal gyrus and pars opercularis emerged.
ConclusionsUsing an unusually large cohort and a meta-analytical approach, our findings point towards a link between prefrontal thinning and negative symptom severity in schizophrenia. This finding provides further insight into the relationship between structural brain abnormalities and negative symptoms in schizophrenia.
Social cognition in people with schizophrenia: a cluster-analytic approach
- P. Rocca, S. Galderisi, A. Rossi, A. Bertolino, P. Rucci, D. Gibertoni, C. Montemagni, M. Sigaudo, A. Mucci, P. Bucci, T. Acciavatti, E. Aguglia, M. Amore, A. Bellomo, D. De Ronchi, L. Dell'Osso, F. Di Fabio, P. Girardi, A. Goracci, C. Marchesi, P. Monteleone, C. Niolu, F. Pinna, R. Roncone, E. Sacchetti, P. Santonastaso, P. Zeppegno, M. Maj, the Italian Network for Research on Psychoses
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- Journal:
- Psychological Medicine / Volume 46 / Issue 13 / October 2016
- Published online by Cambridge University Press:
- 20 September 2016, pp. 2717-2729
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Background
The study aimed to subtype patients with schizophrenia on the basis of social cognition (SC), and to identify cut-offs that best discriminate among subtypes in 809 out-patients recruited in the context of the Italian Network for Research on Psychoses.
MethodA two-step cluster analysis of The Awareness of Social Inference Test (TASIT), the Facial Emotion Identification Test and Mayer–Salovey–Caruso Emotional Intelligence Test scores was performed. Classification and regression tree analysis was used to identify the cut-offs of variables that best discriminated among clusters.
ResultsWe identified three clusters, characterized by unimpaired (42%), impaired (50.4%) and very impaired (7.5%) SC. Three theory-of-mind domains were more important for the cluster definition as compared with emotion perception and emotional intelligence. Patients more able to understand simple sarcasm (⩾14 for TASIT-SS) were very likely to belong to the unimpaired SC cluster. Compared with patients in the impaired SC cluster, those in the very impaired SC cluster performed significantly worse in lie scenes (TASIT-LI <10), but not in simple sarcasm. Moreover, functioning, neurocognition, disorganization and SC had a linear relationship across the three clusters, while positive symptoms were significantly lower in patients with unimpaired SC as compared with patients with impaired and very impaired SC. On the other hand, negative symptoms were highest in patients with impaired levels of SC.
ConclusionsIf replicated, the identification of such subtypes in clinical practice may help in tailoring rehabilitation efforts to the person's strengths to gain more benefit to the person.
Interaction between catechol-O-methyltransferase (COMT) Val158Met genotype and genetic vulnerability to schizophrenia during explicit processing of aversive facial stimuli
- L. Lo Bianco, G. Blasi, P. Taurisano, A. Di Giorgio, F. Ferrante, G. Ursini, L. Fazio, B. Gelao, R. Romano, A. Papazacharias, G. Caforio, L. Sinibaldi, T. Popolizio, C. Bellantuono, A. Bertolino
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- Journal:
- Psychological Medicine / Volume 43 / Issue 2 / February 2013
- Published online by Cambridge University Press:
- 23 May 2012, pp. 279-292
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Background
Emotion dysregulation is a key feature of schizophrenia, a brain disorder strongly associated with genetic risk and aberrant dopamine signalling. Dopamine is inactivated by catechol-O-methyltransferase (COMT), whose gene contains a functional polymorphism (COMT Val158Met) associated with differential activity of the enzyme and with brain physiology of emotion processing. The aim of the present study was to investigate whether genetic risk for schizophrenia and COMT Val158Met genotype interact on brain activity during implicit and explicit emotion processing.
MethodA total of 25 patients with schizophrenia, 23 healthy siblings of patients and 24 comparison subjects genotyped for COMT Val158Met underwent functional magnetic resonance imaging during implicit and explicit processing of facial stimuli with negative emotional valence.
ResultsWe found a main effect of diagnosis in the right amygdala, with decreased activity in patients and siblings compared with control subjects. Furthermore, a genotype × diagnosis interaction was found in the left middle frontal gyrus, such that the effect of genetic risk for schizophrenia was evident in the context of the Val/Val genotype only, i.e. the phenotype of reduced activity was present especially in Val/Val patients and siblings. Finally, a complete inversion of the COMT effect between patients and healthy subjects was found in the left striatum during explicit processing.
ConclusionsOverall, these results suggest complex interactions between genetically determined dopamine signalling and risk for schizophrenia on brain activity in the prefrontal cortex during emotion processing. On the other hand, the effects in the striatum may represent state-related epiphenomena of the disorder itself.