Interacción entre cementos de diferente composición y aditivos superplastificantes

The slump behavior of ordinary Portland-, pozzolanic (red brick powder)-, sulfate resistant-, and limestone cement pastes caused by ≤ 1% additions of polycondensates and polycarboxylates superplasticizers are monitored for up to 90 minutes. With the plolycondensates, Portland- and pozzolanic cements gain fluidity at higher dosages than sulfate resistant and limestone cements. Limestone cement shows the best slump retention. The aluminate and sulfate phases play a major role in the fluidity. With the polycarboxylates, all cements gain fluidity with dosages of ≤ 0.3%. A polycarboxylate with no resonance of methyl methylene proton in the main chain identified in the NMR spectra creates good slump retention. This is explained by a low mobility of the structure and the predominance of the steric effect. The polycarboxylate shows also strong ether bands relative to the ester groups in the IR spectra and a low polydispersity observed in the elution of few low molecular weight species in the HPLC chromatogram.Se ha estudiado el efecto fluidificante (hasta 90 minutos) ejercido por la incorporación de entre 0-1% de aditivos policondensados y policarboxilatos en pastas de cemento Portland, puzolánico, resistente a sulfatos y con adición de caliza. Con la incorporación de los aditivos policondensados, se produjo un incremento de la fluidez de los cementos Portland y puzolánico a mayores dosificaciones que las necesarias en los cementos resistente a sulfatos y con adición de caliza. Éste último presentó la mejor retención de la fluidez. Las fases aluminatos y sulfatos juegan un importante papel en la fluidez inducida. Todos los cementos incrementaron su fluidez con la incorporación de aditivos policarboxilatos a dosificaciones menores del 0,3%. El policarboxilato que no presenta en los espectros de RMN, resonancia asignada al protón de los grupos metil metileno, presenta buena retención de la fluidez. Esto es debido a la baja flexibilidad de la estructura y predominancia del efecto estérico. Este aditivo presenta también, mayor relación de grupos eter frente a grupos ester en los espectros IR, asi como una baja polidispersidad observada en la elución de especies de bajo peso molecular a través de HPLC

Comparison between the Outcomes of Using Biodegradable-Polymer Drug-Eluting Stents and Those of Using Durable-Polymer Drug-Eluting Stents in Acute Coronary Syndrome Patients Undergoing Percutaneous Coronary Intervention

BACKGROUND: Many randomised control studies showed that percutaneous coronary interventions using biodegradable-polymer drug-eluting stents (DES) offer a safe and effective alternative to durable-polymer DES. However, not many studies have discussed its use in the setting of acute coronary syndromes. AIM: We aim to compare the biodegradable-polymer DES with durable-polymer DES when it comes to reducing the incidence of non-ST elevation acute coronary syndrome (NSTEACS) associated with adverse events. METHODS: We enrolled 205 patients presenting with NSTEACS and a TIMI risk score ≥ 3 in this study and divided them into two groups, group A and group B. Biodegradable-polymer DESs were exclusively used in group A, while durable-polymer DESs were used in group B. Major adverse events were reported in both groups during the hospital stay and patients were followed-up for 1 year. RESULTS: In our patients, we intervened on 390 diseased segments in a total of 360 vessels. After intervention, TIMI 0 was achieved in 0.97%, TIMI 1 in 1.46%, TIMI 2 in 2.45%, and TIMI 3 in 95.12% of the treated segments (P-value= 0.677). We implanted 121 biodegradable-polymer DESs and 146 durable-polymer DESs. Clinical success was achieved in 95.12% of our cases. We had 55 patients who needed repeated coronary angiography within 1 year (15 patients treated with biodegradable-polymer DES and 24 patients treated with durable-polymer DES). Eighteen patients experienced angina pains (8 patients treated with biodegradable-polymer DES and 10 patients treated with durable-polymer DES). Only 5 patients needed TLR (2 patients treated with biodegradable-polymer DES and 3 patients treated with durable -polymer DES) (P-value = 0.591), three of them had a myocardial infarction with documented angiographic evidence of significant in-stent restenosis (1 patient treated with biodegradable-polymer DES and 2 patients treated with durable-polymer DESs). CONCLUSION: Biodegradable-polymer DES represents a comparable alternative to durable-polymer DES in the setting of acute coronary syndromes

EFFECT OF ANTIMICROBIAL AGENTS ON SOME CHEMICAL AND MICROBIOLOGICAL CHARACTERISTICS OF VACUUM- PACKAGED GROUND BUFFALO MEAT STORED UNDER REFREGERATED CONDITION

Abstract: The chemical characteristics and microbiological examination of vacuum packaged ground buffalo meat during cold storage for 24 days were determined in order to evaluate two different antimicrobial agents sodium lactate, sodium chloride and their mixture. The results indicated that the use of sodium lactate with or without sodium chloride delayed the proliferation of aerobic plate count, psychrotrophic count, and lactic acid bacterial count, and extended the shelf life up to more than 24 and 21 days respectively, compared to 8 days for the control samples. The TBA values for the samples treated by sodium chloride was not affected, while at the end of storage period the TBA values of samples treated by sodium lactate were significantly reduce the oxidation changes. Therefore, the use of sodium lactate with or without sodium chloride could be used to extend the shelf life of ground buffalo meat during refrigerated storage by reducing both chemical and microbiological changes. Key words: buffalo meat, antimicrobial agents, chemical and microbiological characteristic

EFFECT OF PACKAGING MATERIALS AND TREATMENTS ON THE SHELF LIFE OF CHICKEN BREAST TREATED WITH ANTIMICROBIAL AGENTS AND STORED UNDER REFRIGERATED CONDITION **

Abstract: Sliced chicken breast were treated by dippin in 8 % Sodium lactate (SL) for 2 minutes or in 5 % Potassium sorbate (PS) for 5 minutes. The treated and untreated slices were packaged in two different packaging materials, Low density polyethylene bags (LDPE) at atmospheric pressure, and Laminated pouches (B-650) undervacuum, then stored refrigerated at 4 ºC for 24 days. Color evaluation, total volatile basic nitrogen (TVBN), total bacterial count (TC), psychrophilic bacterial count, coliform group, and sensory evaluation were done in order to study the effect of treatments on the quality and the shelf life of the product. The data indicated that the treatment by (SL) or (PS) solutions was significantly increased the shelf life of the product compared with the untreated samples. It is also showed that the influence of (PS) treatment was the most effectinve in prolonging the shelf life of the sliced chicken breast among all samples. The influence of vacuum storage in keeping quality was better than storage in (LDPE) at atmosheric pressure condition. Also, the shelf life of vacuum packaged treated samples was significantly increased compared with the samples packaged in (LDPE) without vacuum. In conclusion, samples treated by (PS) and packaged under vacuum had the longest shelf life and the best quality than the others

THE EFFECT OF MUNG BEAN POWDER, AND/OR LOW FAT SOY FLOUR AS MEAT EXTENDER ON THE CHEMICAL, PHYSICAL, AND SENSORY QUALITY OF BUFFALO MEAT PRODUCT

Abstract: The chemical, physical, and sensory evaluation of buffalo meat patties was evaluated in order to study the effect of adding low fat soy flour and/or mung bean powder as meat extenders. The results indicated that using low fat soy flour or mung bean powder as meat extenders at a level of 10 % reduced the moisture and fat content, whereas increased the fiber and protein contents in the cooked samples. The reduction was greatest in the control (100 % buffalo meat), and lowest in the sample containing 5 % of both low fat soy flour and mung bean powder. The cooking treatment increased the expressible water for the control and 10 % low fat soy flour samples, and increased the protein water coefficient for all samples. The Feder value for sample containing 5 % of both low fat soy flour and mung bean powder was similar to the control one. The addition of mung bean powder increased the water holding capacity, whereas the addition of low fat soy flour and mung bean powder as meat extenders decreased the cooking loss in the formulated patties. The lowest value was in the sample containing 5 % of both extenders. Samples containing 5 % of both low fat soy flour and mung bean powder had the highest water retention value, whereas the sample with 10 % low fat soy flour had the highest fat retention value. Samples containing 5 % of both low fat soy flour and mung bean powder had the highest values for color, taste, odor, juiciness, and overall acceptability among the other samples. Key words: mung bean, low fat soy flour, meat extenders, buffalo meat product, physical and sensory qualit