Sumário

Sumári

Microbial contamination associated with the processing of tchachanga, a roasted meat product

This study aimed to assess the microbiological contamination and quality of tchachanga, a roasted meat braised product processed at traditional scale in Benin, West Africa. A survey was performed to collect samples of tchachanga and data related to hygienic conditions of the roasted meat processing environment. A total of 60 samples of tchachanga including skewers, roasted meat and seasoned wrapped meat were collected from different processing sites in Cotonou, Benin. The main food borne microorganisms involved were investigated using standard methods. Moreover, a follow-up of tchachanga processing was performed to identify contamination factors of the product. In this respect, samples were collected at certain steps during the processing, and various microorganisms such as coliforms, pathogenic Staphylococcus and Salmonella were traced. The number of mesophilic aerobic bacteria in different products ranged between 6.47±0.61 and 6.93±0.43 Log (cfu/g). Total coliforms, faecal coliforms and Staphylococci ranged from 1.59 to 4.79, 1.00 to 3.2 and 3.49 to 5.2 Log (cfu/g), respectively. No significant differences were observed in the microbial count of different types of tchachanga investigated, but different processing methods had significant changes in the microbial content of the samples as a result of the processing environments and the ingredients used. The presence of Salmonella sp. was observed in all products.Keywords: Street food, Tchachanga, meat, microbiology, qualityAfrican Journal of Biotechnology Vol. 12(18), pp. 2449-245

Stratosphere-troposphere exchange: Chemical sensitivity to mixing

We present examples of how chemical evolution can exhibit sensitivity to mixing arising from stratosphere-troposphere exchange. A chemical transport model is used to survey the chemical contrasts on isentropic surfaces that intersect the tropopause. Significant cross-tropopause gradients in both ozone and water vapor are shown to exist between 300 and 340 K, Back trajectories are used to confirm that air parcels with widely varying chemical properties are rapidly brought together in a typical quasi-isentropic stratosphere-troposphere exchange event. A two-box model is used to investigate the chemical evolution of stratospheric and tropospheric air parcels and to determine the effect of mixing between them. Mixing of stratospheric ozone and tropospheric water vapor is shown to lead to enhanced hydroxyl (OH) radical concentrations compared with background tropospheric and stratospheric values. The oxidation of CO, methane, and higher hydrocarbons is correspondingly increased, and NOx is also lost more rapidly with faster mixing. Also, in low NOx conditions, the rate of O-3 loss is found to increase with faster mixing, The consequences of this anomalous chemistry for chemical transport in stratosphere-troposphere exchange events are discussed. It is also noted that if NOx levels in either parcel are very high initially, mixing of NOx can become more important than O-3 or H2O in determining OH levels

Cu Electrodeposition on Nanostructured MoS2 and WS2 and Implications for HER Active Site Determination

Cu electrodeposition in both underpotential and overpotential regimes on nanostructured MoS2 and WS2 prepared by plasmaenhanced atomic layer deposition has been studied in detail. A combination of electrochemical methods, advanced characterization by X-ray absorption spectroscopy (XAS) as well as theoretical modelling were employed to reveal Cu adsorption modes on transition metal dichalcogenides (TMDs) from initial stages until bulk deposition. Since Cu UPD on TMDs has been used recently to evaluate the number of electrochemically active sites (NAS) for H2 evolution reaction, we evaluate and discuss here the implications of the Cu electrodeposition phenomena on nanostructured MoS2 and WS2 gauging the general applicability of the Cu UPD method for number of HER active sites determination in TMDs. Although an apparently better correlation of HER current density with Cu UPD charge than with double layer capacitance is found, the Cu UPD method cannot be used quantitatively because of the absence of a clear H UPD phenomenon on the studied nanostructured TMDs. This is in contrast to platinum group metal catalysts where H UPD and Cu UPD sites are strongly correlated

Negative symptoms, neurological signs and neuropsychological impairments in 204 Hong Kong Chinese patients with schizophrenia

Background. Studies of the relationship between negative symptoms, neuropsychological impairments and neurological signs in schizophrenia have yielded inconsistent results. In addition, little attention has been directed to address the extent of cultural modulation of negative symptoms. Method. We carried out cross-cultural validation of the High Royds Evaluation of Negativity Scale (HEN) in 50 Hong Kong Chinese patients with schizophrenia. We then investigated the relationship between negative symptoms, neurological signs and neuropsychological impairment in 204 patients. Results. Good interrater reliability, internal reliability, convergent and discriminant validity were found with the HEN. The HEN contained four factors corresponding to 'behaviour', 'functioning', 'thought' and 'appearance'. Negative symptoms were correlated with semantic fluency but not with Wisconsin Card Sorting Test performance or sustained attention. Negative symptoms were also correlated with tardive dyskinesia and catalonia but not with soft neurological signs. Conclusions. Cross-cultural robustness of the negative symptoms construct is supported. Association of negative symptoms with a specific profile of neurocognitive impairment suggests diversity within deficit domains in schizophrenia.link_to_subscribed_fulltex

A confirmatory factor analytic study of symptom dimentisons in schizophrenia

These journal issues entitled: Abstracts of the Ninth Biennial Winter Workshop on Schizophreni

Neurological signs, age, and illness duration in schizophrenia

Although increased prevalence of neurological signs in schizophrenia may reflect the presence of subtle brain dysfunctions, it is not clear whether there is progressive deterioration in such neurological function as the illness advances. This study compared neurological signs in patients with different durations of illness, controlling for age and education level. No deterioration in neurological signs as a function of illness duration was observed. Although there was an increase in neurological signs with age, there was a parallel increase in a control group. In addition, no change in the profile of subgroups of neurological signs was detected. These data provide further evidence for the stability of neurological dysfunction in schizophrenia. The findings are discussed in the context of the developmental origin of neurological dysfunction in schizophrenia.link_to_subscribed_fulltex