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| 3. |
- Bollella, Paolo, et al.
(författare)
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Highly sensitive, stable and selective hydrogen peroxide amperometric biosensors based on peroxidases from different sources wired by Os-polymer : A comparative study
- 2018
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Ingår i: Solid State Ionics. - : Elsevier BV. - 0167-2738. ; 314, s. 178-186
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Tidskriftsartikel (refereegranskat)abstract
- A comparison was made between two plant peroxidases, cationic horseradish peroxidase (HRP) and anionic tobacco peroxidase (TOP), combined with a highly cationic osmium polymer [Os(4,4'-dimethyl-2,2'-bipyridine)2poly(N-vinylimidazole)10Cl]+2/+ ([Os(dmp)PVI]+/2+) to develop highly sensitive, stable and selective hydrogen peroxide biosensors. The two different plant peroxidases were individually immobilized onto graphite rod (G) electrodes by a three steps drop-casting procedure consisting of the subsequent deposition of an aqueous solution of ([Os(dmp)PVI]+/2+), followed by a solution of poly(ethyleneglycol) diglycidyl ether (PEGDGE), used as a cross linking agent and finally an aliquot of a solution of cationic HRP or anionic TOP to make HRP/PEGDGE/[Os(dmp)PVI]+/2+/G and TOP/PEGDGE/[Os(dmp)PVI]+/2+/G based electrodes, respectively. Electrochemical experiments were carried out to investigate the influence of the surface charge of the enzyme and the charge of the polymer on the efficiency of the electron transfer (ET) between the enzyme and the wiring redox polymer and the efficiency for electrocatalytic reduction of H2O2. In the case of HRP a decrease in the ET rate was observed due to the repulsion between this enzyme and the polymer, both positively charged, whereas with TOP there was an enhanced ET rate due to the attraction between the anionic enzyme and the cationic polymer. The effects of enzyme loading and pH were investigated. Both peroxidase modified electrodes exhibited a wide dynamic response range (1-500μM H2O2) and a low detection limit (0.3μM H2O2). The TOP based electrode showed a higher sensitivity (470nAμM-1 cm-2) compared to that of the HRP based electrode (300nAμM-1 cm-2) and an improved long-term stability (decrease in 17.3% upon 30days compared with 50% for HRP). Both enzyme electrodes showed a response time of 3s. The HRP based sensor was more sensitive to the presence of phenolic compounds acting as alternative electron donors, whereas the TOP based sensor was virtually interference free. Both HRP and TOP based electrodes were successfully tested in contact lens cleaning samples and real "spiked" samples from different sources such as tap water, milk and dairy products.
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- Kebede, D, et al.
(författare)
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Onset and clinical course of schizophrenia in Butajira-Ethiopia--a community-based study.
- 2003
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Ingår i: Social Psychiatry and Psychiatric Epidemiology. - : Springer. - 0933-7954 .- 1433-9285. ; 38:11, s. 625-631
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Tidskriftsartikel (refereegranskat)abstract
- Background: There are reports on favourable course and outcome of schizophrenia in lowincome countries. The aim of the present study was to examine onset and clinical course of the illness in a community-based sample in rural Ethiopia based on crosssectional information. Method: A two-stage survey was carried out in Butajira-Ethiopia, a predominantly rural district. Altogether 68,378 individuals aged 15–49 years were CIDI-interviewed, of whom 2,159 were identified as cases according to the CIDI interview with regard to psychotic or affective disorders. Key informants identified another group of 719 individuals as being probable cases and a total of 2,285 individuals were SCAN-interviewed. The present paper reports on cases with schizophrenia. Results: There were 321 cases of schizophrenia giving an estimated lifetime prevalence of 4.7/1,000). Of the cases,83.2% (N = 267) were males. Mean age of first onset of psychotic symptoms for males was 23.8 (sd 8.6) compared to 21.0 (sd 7.8) for females (P = 0.037; 95 %CI 0.16–5.47). Over 80% had negative symptoms and over 67% reported continuous course of the illness. Less than 10% had a history of previous treatment with neuroleptic medication. About 7% were vagrants, 9 % had a history of assaultive behaviour,and 3.8% had attempted suicide. The male to female ratio was nearly 5:1. Conclusion: This large community-based study differs from most previous studies in terms of higher male to female ratio, earlier age of onset in females and the predominance of negative symptoms.
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- Lemma, Kelemu, et al.
(författare)
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Kinetics and mechanism for reduction of halo- and haloam(m)ine platinum(IV) complexes by L-ascorbate
- 2002
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Ingår i: Inorganica Chimica Acta. - 0020-1693. ; 331, s. 98-108
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Tidskriftsartikel (refereegranskat)abstract
- Reduction of the model platinum(IV) complexes cis-[PtCl4(NH3)(2)] (1), trans-[PtCl4(NH3)(2)] (2). trans-[PtCl2(en)(2)](2+) (3), trans-[PtBr2(NH3)(4)](2+) (4), [PtCl6](2-) (5), and [PtBr6](2-) (6) with L-ascorbic acid (H(2)Asc) in 1.0 M aqueous medium at 25 degreesC in the region 1.75 less than or equal to pH less than or equal to 7.20 has been investigated using stopped-flow spectrophotometry. The redox reactions follow the rate law: -d[Pt(IV]/dt = k[H(2)Asc](tot)[Pt(IV)] where k is a pH-dependent second-order rate constant and [H(2)Asc](tot), the total concentration of ascorbic acid. The pH-dependence of k is attributed to parallel reduction of Pt(IV) by the protolytic species HAsc(-) and Asc(2-). Analysis of the kinetics data reveals that the ascorbate anion Asc(2-) is up to seven orders of magnitude more reactive than HAsc(-) while H(2)Asc is unreactive. Electron transfer from HAsc(-)/Asc(2-) to the Pt(IV)) compounds is suggested to take place by a mechanism involving a reductive attack on any one of the mutually trans-halide ligands by Asc(2-) and/or HAsc(-) forming a halide-bridged activated complex, The rapid reduction of these complexes supports the assumption that ascorbate Asc(2-) might be an important reductant at physiological conditions for anticancer active Pt(IV) pro-drugs capable of undergoing reductive trans elimination. The parameters DeltaH(not equal) and DeltaS(not equal) for reduction of Pt(IV) with Asc(2) hake been determined from the study of the temperature dependence of k. (C) 2002 Elsevier Science B.V. All rights reserved.
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- Shibre, Teshome, et al.
(författare)
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Neurological soft signs (NSS) in 200 treatment-naïve cases with schizophrenia : a community-based study in a rural setting.
- 2002
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Ingår i: Nordic Journal of Psychiatry. - : Informa UK Limited. - 0803-9488 .- 1502-4725. ; 56:6, s. 425-31
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Tidskriftsartikel (refereegranskat)abstract
- Several studies have reported neurological soft signs (NSS) to be common in individuals with schizophrenia. The majority of these studies are based on clinical samples exposed to neuroleptic treatment. The present study reports on 200 treatment-naïve and community-identified cases of schizophrenia and 78 healthy individuals from the same area, evaluated using the Neurological Evaluation Scale (NES). The median NES score was 5.0 for cases of schizophrenia and 1.5 for healthy subjects. The impairment rate of NSS in cases with schizophrenia was 65.0% against 50.0% in healthy subjects, and the difference was statistically significant (chi2 = 5.30; df = 1; P < 0.021). NSS abnormality is as common in treatment-naïve cases as reported in many studies in those on neuroleptic medication. There was no significant relation between the NSS impairment and duration of illness, remission status, positive symptoms, negative symptoms and disorganized symptoms.
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| 8. |
- Shibre, Teshome, et al.
(författare)
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Schizophrenia : illness impact on family members in a traditional society--rural Ethiopia.
- 2003
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Ingår i: Social Psychiatry and Psychiatric Epidemiology. - : Springer. - 0933-7954 .- 1433-9285. ; 38:1, s. 27-34
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Tidskriftsartikel (refereegranskat)abstract
- Background: Studies have consistently shown that both the subjective and objective dimensions of burden among family members of schizophrenia patients and other psychiatric disorders are prevalent. However, as most of these reports were from western societies, we lack information on the subject in developing countries. Method: The study was conducted within the framework of the ongoing epidemiological study of course and outcome of schizophrenia and bipolar disorders in a rural population of 15–49 years of age. Three hundred and one cases of schizophrenia and their close relatives participated in the study. Results: Family burden is a common problem of relatives of cases with schizophrenia. Financial difficulty is the most frequently endorsed problem among the family burden domains (74.4 %). Relatives of female cases suffered significantly higher social burden (Z = 2.103; p = 0.036). Work (Z = 2.180; p = 0.029) and financial (Z = 2.088; p = 0.037) burdens affected female relatives more often than males. Disorganised symptoms were the most important factors affecting the family members in all family burden domains. Prayer was found to be the most frequently used coping strategy in work burden (adj. OR = 1.99; 95 % CI = 1.08–3.67; p = 0.026). Conclusion: Negative impact of schizophrenia on family members is substantial even in traditional societies such as those in Ethiopia where family network is strong and important. The scarce existing services in the developing countries should include family interventions and support at least in the form of educating the family members about the nature of schizophrenia illness and dealing with its stigma and family burden.
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