52 research outputs found

    Visual processing deficits in 22q11.2 Deletion Syndrome.

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    Carriers of the rare 22q11.2 microdeletion present with a high percentage of positive and negative symptoms and a high genetic risk for schizophrenia. Visual processing impairments have been characterized in schizophrenia, but less so in 22q11.2 Deletion Syndrome (DS). Here, we focus on visual processing using high-density EEG and source imaging in 22q11.2DS participants (N = 25) and healthy controls (N = 26) with an illusory contour discrimination task. Significant differences between groups emerged at early and late stages of visual processing. In 22q11.2DS, we first observed reduced amplitudes over occipital channels and reduced source activations within dorsal and ventral visual stream areas during the P1 (100-125 ms) and within ventral visual cortex during the N1 (150-170 ms) visual evoked components. During a later window implicated in visual completion (240-285 ms), we observed an increase in global amplitudes in 22q11.2DS. The increased surface amplitudes for illusory contours at this window were inversely correlated with positive subscales of prodromal symptoms in 22q11.2DS. The reduced activity of ventral and dorsal visual areas during early stages points to an impairment in visual processing seen both in schizophrenia and 22q11.2DS. During intervals related to perceptual closure, the inverse correlation of high amplitudes with positive symptoms suggests that participants with 22q11.2DS who show an increased brain response to illusory contours during the relevant window for contour processing have less psychotic symptoms and might thus be at a reduced prodromal risk for schizophrenia

    Dentinogenesis imperfecta in Osteogenesis imperfecta type XI in South Africa: a genotype–phenotype correlation

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    BACKGROUND: The maxillofacial and dental manifestations of Osteogenesis imperfecta (OI) have significant implications in terms of management. Although the occurrence of abnormal dentine in some forms of OI is well documented, there is scant information on the association of abnormal dentine in the Black African persons with phenotypic OI III and genotypic OI XI in South Africa. METHODS: This was a cross-sectional analytic study. A series of 64 Black South African individuals with a confirmed phenotypic diagnosis of OI III, ages ranging from 3 months to 29 years, were assessed clinically, radiographically, and at a molecular level. RESULTS: A total number of 64 saliva samples were analyzed and 3 DNA variations were identified in exon 5 of the FKBP10 gene. The homozygous mutation, c.[831dupC]; [831dupC], was identified in 23 affected persons who had no clinically obvious features of DI in their primary and secondary teeth. Radiologically, mild features of DI were evident in 10 persons in whom radiographic images were obtained and were given a Clinical–radiological score of 2. A compound heterozygous mutation, c. [831delC]; [831dupC], was identified in three siblings. An intraoral examination of these affected persons revealed no clinically apparent features of DI in their primary and secondary teeth. Due to the lack of radiological facilities, the presence or absence of DI could not be confirmed or negated. A second compound heterozygous mutation, c.[831dupC]; [1400-4C>G], was identified in a female of 29 years belonging to the Xhosa linguistic group. Her teeth appeared clinically normal but it was not possible to obtain radiographs. In 37 affected individuals, no disease-causing mutations were identified. CONCLUSION: Black African individuals in SA with the homozygous mutation in the FKBP10 gene have clinically unaffected teeth yet exhibited radiographic features of DI to varying degrees. This characterization is suggestive of a relationship between the genetic abnormality and the clinical manifestations of DI. The authors suggest that this diagnosis must include teeth that are clinically and/or radiologically aberrant, and should not exclude the presence of other, milder, dentinal aberrations associated with OI. There was no correlation between severity of OI and DI in this cohort of individuals

    Diagnostic Values of Laser Fluorescence Device with Other Techniques in Occlusal Caries Detection

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    Objective: The aim of the present study was to compare the performance of laser fluorescence (LF) method with other conventional diagnostic techniques in detection of smallocclusal caries in permanent teeth.Materials and Methods: Prior to this in vitro diagnostic study, a pilot study assessed intra-examiner reliability and reproducibility. The occlusal surfaces of 90 extracted human premolars were examined with four diagnostic methods: probing, visual inspection, bitewing(BW) radiographs, and LF. The teeth were then sectioned for the purpose of histological examination. The data were analyzed using SPSS 15 software, and sensitivity,specificity and other diagnostic criteria of the techniques were calculated.Results: The intra-examiner reproducibility for probing and also radiographic techniques was 100%. The corresponded figure for LF (88%) was more than visual inspection (82%).The highest level of validity of the examiner turned out to be in probing technique(76.9%). Sensitivity of visual inspection, probing, and LF methods was 54.5% and that of BW radiography was 27.5%. Specificity and efficiency of LF method were 84.8% and 81.1%, respectively. Probing and visual inspection showed the highest specificity (97.5% and 94.9, respectively) and efficiency (92.2% and 90%, respectively) among the methods.Conclusion: Specificity and efficiency of LF method were lower compared to those of other methods. Among all the investigated methods, the most efficient methods in the diagnosis of small occlusal caries in permanent teeth were probing and visual inspection,respectively

    Al-Fayḍ al-Kâshânî (1598-1680) on self-supervision and self-accounting

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    By examining first the life and works of Muhammad ibn Murtada al-Fayd al-Kashani (1007/1598-1091/1680), we hope this will serve as an introduction to some of his viewpoints. We will consider his theories of muraqabat al-nafs (self-supervision) and muhasabat al-nafs (self-accounting) as expounded in his book al-Mahajjah al-Bayda', which was written as a work to enhance Ihya' al-'Ulum by al-Ghazali, (450/1058-505/1111) from a Shi'ah perspective. We will also compare the views of al-Fayd and al-Ghazali as expressed in their respective books.Self-supervision and self-accounting are two main terms of ethical terminology that enjoy a rich history in Islamic philosophy. Al-Fayd's views on the subject, as a philosopher and an ethicist of the School of Isfahan are studied in this work. The sources of al-Ghazali and al-Fayd are discussed, and differences between the approaches of al-Fayd and al-Ghazali are also covered

    Laboratory Studies of MEOR in the Micromodel as a Fractured System

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    Abstract Microbial enhanced oil recovery (MEOR) is receiving renewed interest worldwide in recent years as a viable method while not damaging the reservoir is proven to be remarkably effective, however to some extent costly. This method is based on microorganisms' activities to reduce residual oil of reservoirs, which is dependent on behavior of inherent microorganisms or injection of bio-product of external microorganisms. In this work, five bacterial species were taken from MIS crude oil that is one of the aging Persian fractured reservoirs. These microorganisms are substantially strong in increasing oil recovery especially by reducing IFT and other MEOR mechanisms such as change of wettability of rock at the favorable condition for the activities of these bacteria observed within the temperature range of 50°C to 90°C at the atmospheric pressure. Two series of visualization experiments were carried out to examine the behavior of microbial enhanced oil recovery in micromodels designed to resemble the fractured system: static and dynamic. In the static one, carbonate rock-glass micromodel is used to simulate the reservoir conditions and the latter is performed by a glass micromodel which has a fracture with 45 degree inclination. The image processing methodology is used to determine the recovery achieved by MEOR in the micromodel made of glass. Introduction A prevalent question in the oil industry is: what is the best method for improving the recovery factor of a certain reservoir? Jumping to the answer is not always an easy task. The effectiveness of a method in a specific reservoir does not necessarily guarantee the chance of success somewhere else. Essentially the prevailing condition of a reservoir is the determining factor in success or failure of a method. So, if the method is designed in a way the least affecting the reservoir, there would be a higher chance of success. MEOR is one of these lately high-profile methods. Even though, this method can be very powerful, but its associating problems are still to be taken into thorough consideration. MEOR has long been considered by hydrocarbon-related scientists and microbiologists as an effective method to recover tertiary oil from reservoirs. MEOR can recover tertiary oil by improving macroscopic sweep efficiency through microbially induced permeability profile modification; or reducing interfacial tension between oil and water with microbial bio-surfactants to lower the capillary trapping forces; or stimulating the reservoir porosity and permeability with microbial products such as acids, or combining all three mechanisms. This paper concentrates mainly on the application of bio-organisms which are also referred to as microorganisms throughout this study to recover residual oil trapped within the pores of a rock. The glass micromodels are largely used for visualization purposes in literature. In addition to conventional micromodels two other types were also utilized which could be considered as hybrid models of the reservoir rock and a micromodel. At the end of the water-flooding of reservoirs, a large quantity of oil may remain trapped within the reservoir. The oil is retained by capillary forces acting on oil globules within the porous medium. Surfactants reduce capillary forces by lowering the interfacial tension between oil and water. This allows any displacing force such as the viscous force of injected or flowing surfactant to recover some of this oil. Microbial bio-surfactants are similar to synthetic surfactants in terms of the oil recovery mechanism. What differentiates them from synthetic surfactants is that they are generated in situ, inside the reservoir, by microbes when sufficient nutrients and suitable conditions are present. Primary Microbial Culture A new surface sample of the MIS oil was taken at the well head and physical specifications were measured at the lab. This is fairly light oil with API gravity of 42.5. The respective specifications are according to the table 1. M. Nourani, H. Panahi, D. Biria, R. Roosta Azad, M. Haghighi and A. Mohebb

    Abnormal development of early auditory processing in 22q11.2 Deletion Syndrome

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    Abstract The 22q11.2 Deletion Syndrome (22q11.2 DS) is one of the highest genetic risk factors for the development of schizophrenia spectrum disorders. In schizophrenia, reduced amplitude of the frequency mismatch negativity (fMMN) has been proposed as a promising neurophysiological marker for progressive brain pathology. In this longitudinal study in 22q11.2 DS, we investigate the progression of fMMN between childhood and adolescence, a vulnerable period for brain maturation. We measured evoked potentials to auditory oddball stimuli in the same sample of 16 patients with 22q11.2 DS and 14 age-matched controls in childhood and adolescence. In addition, we cross-sectionally compared an increased sample of 51 participants with 22q11.2 DS and 50 controls divided into two groups (8–14 and 14–20 years). The reported results are obtained using the fMMN difference waveforms. In the longitudinal design, the 22q11.2 deletion carriers exhibit a significant reduction in amplitude and a change in topographic patterns of the mismatch negativity response from childhood to adolescence. The same effect, reduced mismatch amplitude in adolescence, while preserved during childhood, is observed in the cross-sectional study. These results point towards functional changes within the brain network responsible for the fMMN. In addition, the adolescents with 22q11.2 DS displayed a significant increase in amplitude over central electrodes during the auditory N1 component. No such differences, reduced mismatch response nor increased N1, were observed in the typically developing group. These findings suggest different developmental trajectories of early auditory sensory processing in 22q11.2 DS and functional changes that emerge during the critical period of increased risk for schizophrenia spectrum disorders
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