| 26401. |
- Chorro, Matthieu, et al.
(författare)
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Discriminated structural behaviour of C60 and C70 peapods under extreme conditions
- 2007
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Ingår i: Europhysics letters. - : IOP Publishing. - 0295-5075 .- 1286-4854. ; 79:5, s. 56003-
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Tidskriftsartikel (refereegranskat)abstract
- We studied structural changes in C60 and C70 peapods—i.e. C60 and C70 chains inserted inside single-walled carbon nanotubes—when submitted to high pressure and temperature conditions. X-ray diffraction experiments showed that while C60 molecules polymerize inside nanotubes at pressures and temperatures consistent with polymerization in bulk C60 phases, no polymerization is observed in C70 peapods, even at pressures and temperatures above the threshold for polymerization in bulk C70. Tubular confinement in the nanotube container prevents the monomers to rearrange in the way needed for polymerization. This result testifies for the strong influence of confinement on the behaviour of C70.
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| 26402. |
- Chotai, Jayanti, et al.
(författare)
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A dual vulnerability hypothesis for seasonal depression is supported by the seasonal pattern assessment questionnaire in relation to the temperament and character inventory of personality in a general population.
- 2004
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Ingår i: Journal of Affective Disorders. - : Elsevier BV. - 0165-0327 .- 1573-2517. ; 82:1, s. 61-70
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Personality structure obtained from the psychobiological Temperament and Character Inventory (TCI) was studied in relation to self-reported seasonal variations in mood and behavior measured by the Seasonal Pattern Assessment Questionnaire (SPAQ). METHODS: The subjects comprised 1761 adults (57.6% women) in the age range 35-85 years, enrolled in the Betula prospective random cohort study of Umea, Sweden. RESULTS: Personality profiles of subjects who reported the occurrence of a high degree of seasonal variation as such were associated with a combination of high self-transcendence (ST) and high persistence (PS), irrespective of the level of harm avoidance (HA). Subjects who reported feeling worst in winter were associated with high HA, irrespective of the levels of ST and PS. Also, subjects feeling worst in summer or experiencing overall problems with seasonal variation were associated with high HA in their personality profiles. Using the SPAQ criteria to define seasonal affective disorder (SAD) or subsyndromal SAD (S-SAD), subjects with these disorders often had combinations of high self-transcendence (ST) and high persistence (PS), but with different associations with HA. LIMITATIONS: No evaluations were made for SAD or subsyndromal SAD according to the DSM-IV or ICD 10 criteria. CONCLUSIONS: Our results relating SPAQ with TCI give support for a dual vulnerability hypothesis for seasonal depression proposed in the literature, where it is attributed to a combination of a seasonal factor and a depression factor. Examining the literature regarding the relationships between the different TCI scales and monoamine neurotransmitter functions, those relationships suggest that these two vulnerability factors for seasonal depression may be modulated by different neurotransmitter systems.
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| 26403. |
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| 26404. |
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| 26405. |
- Chotai, Jayanti, et al.
(författare)
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Anticipation in Swedish families with schizophrenia.
- 1995
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Ingår i: Psychiatric Genetics. - 0955-8829 .- 1473-5873. ; 5:4, s. 181-6
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Tidskriftsartikel (refereegranskat)abstract
- Nineteen parent-offspring pairs obtained from 14 two-generation families with available medical records and diagnosis of schizophrenia were studied to compare the ages of onset of the parent generation with those of the offspring generation. The mean age of onset for the parent generation was 37.3 +/- 6.0 years and for the offspring generation was 20.8 +/- 4.4. The mean difference was thus 16.5 +/- 6.2, suggesting the occurrence of anticipation in schizophrenia (p < 0.001). Although some ascertainment biases (like reduced fertility in early-onset parents or early detection of symptoms in offsprings of affected parents) may partially contribute to the occurrence of anticipation, this study replicates recent reports of anticipation in several neuropsychiatric disorders, some of which have been shown to be associated with unstable expansions of trinucleotide repeats in the genomic DNA.
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| 26406. |
- Chotai, Jayanti, et al.
(författare)
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Cerebrospinal fluid monoamine metabolite levels in human newborn infants born in winter differ from those born in summer.
- 2006
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Ingår i: Psychiatry Research. - : Elsevier BV. - 0165-1781 .- 1872-7123. ; 145:2-3, s. 189-97
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Tidskriftsartikel (refereegranskat)abstract
- An earlier study has shown significant differences in the CSF monoamine metabolite levels in adults born during different seasons of the year. We study here the relationship between season of birth and CSF monoamine metabolite levels in 283 newborn febrile infants without neurological abnormalities, with an age distribution ranging from birth to about 3 months, adjusting for the confounding variables age and time at lumbar puncture, weight at birth, estimated gestational age at birth, gender, race, and medicaid status. Each of the three metabolite levels as well as their ratios HVA/5-HIAA and 5-HIAA/MHPG showed significant month-of-birth variations, but not the ratio HVA/MHPG. For HVA and MHPG levels, the maximum was obtained around the winter birth months November-December, whereas for 5-HIAA level, the maximum was obtained around the summer birth months June-July. The correlations between HVA and 5-HIAA were, in general, significantly positive within the different birth seasons and races. Among summer-born Caucasian infants, MHPG was significantly positively correlated with HVA and with 5-HIAA, whereas among winter-born Black infants, MHPG was significantly positively correlated with HVA. Season of birth is an unspecific environmental factor that may be proxy for several possible seasonally varying environmental circumstances such as the length of photoperiod, temperature, infections, nutrition, stress and lifestyle. Studies relating season of birth to monoaminergic turnover at different stages of life may yield important clues about the gestational and perinatal origins of neurodevelopment.
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| 26407. |
- Chotai, Jayanti, et al.
(författare)
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Converging evidence suggests that monoamine neurotransmitter turnover in human adults is associated with their season of birth.
- 2002
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Ingår i: European Archives of Psychiatry and Clinical Neuroscience. - : Springer Science and Business Media LLC. - 0940-1334 .- 1433-8491. ; 252:3, s. 130-4
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Tidskriftsartikel (refereegranskat)abstract
- Separate studies on adults, including those in suicidology and another regarding personality in the general population, have indicated associations with their season of birth. We analyse each of these studies by multiple nonlinear regression employing a cosine function for the month of birth, and compare these studies regarding the birth months giving the maxima and minima. The method of suicide in suicide studies shows a significant month-of-birth variation similar to that for the serotonin metabolite 5-HIAA in the separate study on cerebrospinal fluid, with a peak around the birth month September and a nadir around birth in March. When comparing the personality study with the study on cerebrospinal fluid, the trait novelty seeking varies similar to that for the dopamine metabolite HVA or the norepinephrine metabolite MHPG, and the trait reward dependence varies similar to that for HVA. The trait self-transcendence varies similar to the ratio of the dopamine and serotonin metabolites. Dopamine turnover in adults thus shows a peak around the birth months November-December, and a nadir around the birth months May-June, suggesting a possible involvement of the length of photoperiod during their perinatal period. These results provide strong evidence for the influence of season of birth on adult monoamine neurotransmitter turnover, and give further support for the monoaminergic modulation of the temperament and character traits.
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| 26408. |
- Chotai, Jayanti, et al.
(författare)
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Gene-environment interaction in psychiatric disorders as indicated by season of birth variations in tryptophan hydroxylase (TPH), serotonin transporter (5-HTTLPR) and dopamine receptor (DRD4) gene polymorphisms.
- 2003
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Ingår i: Psychiatry Research. - 0165-1781 .- 1872-7123. ; 119:1-2, s. 99-111
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Tidskriftsartikel (refereegranskat)abstract
- Genetic and environmental factors, as well as their interactions, are likely to be involved in psychiatric disorders. Considerable progress has been made in association and linkage studies with various candidate genes, at times with conflicting or ambiguous results. An environmental factor that has persistently shown associations with several psychiatric and neurological disorders is the season of birth. If it is the interaction of a specific gene allele with a specific season of birth that constitutes an increased (or decreased) risk for a disorder, then the individuals with this disorder are likely to have a season of birth variation in this gene allele. We investigated the variations in TPH, 5-HTTLPR and DRD4 gene polymorphisms according to seasonality of birth in 954 patients with unipolar affective disorder, bipolar affective disorder, and schizophrenia, respectively, and in 395 controls. We first analyzed season of birth variations in the gene alleles with one cycle or two cycles per year, and then compared specified birth seasons with each other. We found season of birth variations in these gene alleles that were different for different psychiatric disorders. Significant differences between cases and controls could be obtained when restricting the analysis within certain birth seasons but not within others. Our results thus suggest an interaction between the seasons of birth and the expression of the candidate genes, and that season of birth is a confounding variable when investigating the role of the candidate genes in susceptibility to psychiatric disorders.
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| 26409. |
- Chotai, Jayanti, et al.
(författare)
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Interaction between the tryptophan hydroxylase gene and the serotonin transporter gene in schizophrenia but not in bipolar or unipolar affective disorders.
- 2005
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Ingår i: Neuropsychobiology. - : S. Karger AG. - 0302-282X .- 1423-0224. ; 51:1, s. 3-9
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Tidskriftsartikel (refereegranskat)abstract
- Increasing focus is being given to identify possible combinations of genes related to specific clinical phenotypes. In our sample of 814 patients comprising 114 with schizophrenia, 416 with bipolar affective disorder and 284 with unipolar affective disorder, we studied interactions between the tryptophan hydroxylase (TPH), the serotonin transporter (5-HTTLPR), and the dopamine receptor (DRD4) genes in relation to five major psychiatric symptomatology scores. There was significant interaction between the TPH and the 5-HTTLPR genes. With an increasing number of short (s) alleles of 5-HTTLPR, the scores for delusions, disorganization and negative symptoms were significantly decreasing among subjects having the TPH genotype AA but increasing among subjects having the TPH genotype AC, yielding the highest scores for the combinations AA x ll and AC x ss. Since high scores on just delusions, disorganization and negative symptoms but low scores on excitement and depression were found among subjects with schizophrenia, we conducted comparisons among the three diagnostic categories and controls as regards the combined TPH x 5-HTTLPR genotype distribution. Schizophrenia subjects had a significantly different distribution of the genotype combination for TPH x 5-HTTLPR as compared to 241 controls or to unipolar or bipolar subjects, and had significantly higher frequencies of AA x ll and of AC x ss. Thus, an interaction between TPH and 5-HTTLPR genes constitutes susceptibility to schizophrenia, thereby yielding apparent relationships between the major psychiatric symptomatology scores and genotype combinations in samples that are obtained by pooling schizophrenia with other diagnostic categories.
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| 26410. |
- Chotai, Jayanti
(författare)
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Month of birth in relation to suicide.
- 2008
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Ingår i: British Journal of Psychiatry. - : Royal College of Psychiatrists. - 0007-1250 .- 1472-1465. ; 192:4, s. 313-
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Tidskriftsartikel (refereegranskat)
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