Study of the effect of natural antioxidants in polyethylene: Performance of β-carotene

The effect of β-carotene on the behaviour of polyethylene stabilized with α-tocopherol and a phosphonite antioxidant was studied under processing and storage conditions. The amount of β-carotene ranged between 0 and 2000 ppm. The polymer was characterised by different methods after processing then during and after storage at ambient temperature in light and dark. β-Carotene hinders the oxidation of polyethylene and does not increase the chain extension reactions during processing, though more vinyl groups and phosphonite molecules react. β-Carotene colours polyethylene strongly already at low concentrations. The reactions of the polymer and β-carotene are affected strongly by the storage conditions. The presence of β-carotene does not influence the stabilizing efficiency of the primary and secondary antioxidants. In dark the molecular structure of the polymer does not change appreciably, while the reactions of β-carotene lead to an increase in the yellowness index. In light the molecular characteristics of polyethylene undergo significant changes indicating long chain branching. The polymer fades rapidly after an induction period. The length of the induction period is not influenced by light. The rate of the degradation reactions of β-carotene during storage is controlled by its concentration and film thickness. Visible autoaccelerated decomposition in light renders β-carotene candidate as an indicator in active packaging materials

The use of 0.2% glyceryl trinirate oinment for anal fissures

<b>Aim of the study: </b> To assess the clinical efficacy of 0.2&#x0025; glyceryl trinitrate ointment in the management of acute and chronic anal fissures. <b> Patients and methods: </b> A prospective clinical study conducted on consecutive patients presented to the surgical clinic of King Khalid University Hospital, Riyadh with acute and chronic anal fissures, from January to December 2003. These patients were treated with topical 0.2&#x0025; glyceryl trinitrate paste in soft white paraffin three times a day. Patients were examined at regular intervals to evaluate the fissure status, adverse reactions, symptomatic control and recurrence. <b> Results: </b> This study comprised 121 patients, six of them were lost to follow-up and 109 (94.7&#x0025;) of the remaining 115 patients were cured. Of those cured, 13 patients (11.3&#x0025;) presented with acute and 102 (88.7&#x0025;) with chronic fissures. There were 98 male and 17 female patients with median age of 41 years (range, 14-70 years). Complete symptomatic relief was achieved in all patients within one month of therapy. Two patients, with chronic anal fissures presented with recurrent symptoms within one month of the completion of therapy both of them were successfully treated with repeat glyceryl trinitrate course. Treatment had to be terminated in six (5.2&#x0025;) patients: five (4.3&#x0025;) experienced intolerable adverse effects and one (0.8&#x0025;) patient failed to respond. All these patients were successfully treated with lateral internal sphincterotomy. No patient complained of change in continence. <b> Conclusion: </b> Glyceryl trinitrate ointment produces adequate symptomatic control and healing of the anal fissures and can be considered as one of the recommended treatment option

Use of 0.2% glyceryl trinitrate oinment for annal fissures

Aim of the study: To assess the clinical efficacy of 0.2% glyceryl trinitrate oinlment in the management of acute and chronic anal fissures. Patients and methods: A prospective clinical study conducted on consecutive patients presented to the surgical clinic of King Khalid University Hospital, Riyadh with acute and chronic anal fissures, from January to December 2003. These patients were treated with topical 0.2% glyceryl trinitrate paste in soft white paraffin three times a day. Patients were examined at regular intervals to evaluate the fissure status, adverse reactions, symptomatic control and recurrence. Results: This study comprised 121 patients, six of them were lost to follow-up and 109 (94.7%) of the remaining 115 patients were cured. Of those cured, 13 patients (11.3%) presented with acute and 102 (88.7%) with chronic fissures. There were 98 male and 17 female patients with median age of 41 years (range, 14-70 years). Complete symptomatic relief was achieved in all patients within one month of therapy. Two patients, with chronic anal fissures presented with recurrent symptoms within one month of the completion of therapy both of them were successfully treated with repeat glyceryl trinitrate course. Treatment had to be terminated in six (5.2%) patients: five (4.3%) experienced intolerable adverse effects and one (0.8%) patient failed to respond. All these patients were successfully treated with lateral internal sphincterotomy. No patient complained of change in continence. Conclusion: Glyceryl trinitrate ointment produces adequate symptomatic control and healing of the anal fissures and can be considered as one of the recommended treatment option

Oxidation of β-Carotene. Site of Initial Attack

The reaction between β-carotene and molecular oxygen in toluene at 60° was investigated. A linear relation was found between the loss in β-carotene and time. The reaction rate increased with increasing temperature. The activation energy, Εa, for the oxidation of β-carotene was found to be 10.2 kcal/mol. Though free-radical initiators caused rate enhancement, the kinetics of the reaction and the light absorption characteristics of the reaction solution were altered. This indicated a difference in the mechanism of the reaction in the presence of free-radical initiators. The rate of loss of β-carotene was increased in the presence of cupric ions and decreased in the presence of diphenylamine. The products of the reaction were β-carotene 5,6-monoepoxide and its isomer, β-carotene 5,6,5′,6′-diepoxide, and β-carotene 5,8-monoepoxide and its isomer, β-carotene 5,8,5′,8′-diepoxide. A reaction mechanism was proposed. © 1970, American Chemical Society. All rights reserved

Biochemical and Sensory Evaluation of Carotene and Protein Enriched Biscuits

Page(s): 9 (1), 104-113, 17 Ref.Market biscuits prepared conventionally from wheat flour were supplemented with legume flour and carrot powder to enhance their protein and vitamin A levels, respectively. Addition of 18% chick pea or pigeon pea flours to wheat flour biscuits increased the protein content from 10% in market biscuits to 13.5% in supplemented samples. Incorporation of carrot powder at 10% level gave vitamin A content of 426 RE/100g for chick pea supplemented biscuits against 39l RE/100g for pigeon pea supplemented biscuits. Chickpea biscuits recorded best preference among penalists and were significantly (P£0.05) better than pigeon pea biscuits. The essential amino acid lysine was significantly (P£0.05) improved from 1.26 g/100g protein in conventional market biscuits to 3.39 g/100g protein in chickpea biscuits, which possessed higher in vitro protein digestibility (95%) compared to market biscuits (82.5%). The calculated protein efficiency ratio of chickpea biscuits (1.6) was significantly (P£0.05) higher than that of the market biscuits (0.81).Khartoum University Pres