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Preparation of laboratory-scale polyurethane foams is described with formulations that are easy to implement in experiments for undergraduate students. Particular attention is given to formulation aspects that are based on the main chemical reactions occurring in polyurethane production. This allows students to develop alternative formulations to the ones given in the experimental procedure. Chemicals and methods used in the experiment are similar to those used in the polyurethane industry, so students gain insight about the chemistry involved in polyurethane foam production. Foam characterization by apparent bulk density is also described and an example of the expected results is given. Additional characterization experiments are suggested with some alternative foam formulations. (Contains 1 figure and 1 table.)

This study investigates how cocoa rootstocks respond to flooding and post-flooding conditions, offering insights for cocoa plantation sustainability in flood-prone areas due to climate change. We studied Theobroma cacao L. rootstocks for 60 d of flooding and 30 d post-flooding, grafting PS-1319 scions onto five rootstocks (TSH-1188, Cepec-2002, Pará, Esfip-02, SJ-02). Photochemical performance remained stable across rootstocks, while flooding progressively reduced electron transport efficiency. Photochemical damage emerged after 7 d, worsening occurred at 19 d. Although post-flooding efficiency improved, recovery time was insufficient for full restoration. Stem diameter increased less in Esfip-02. TSH-1188 had the highest stem dry mass during flooding and the most root and total dry mass during postflooding. SJ-02 had the lowest stem dry mass and post-flooding total dry mass. Principal component analysis revealed stem and root development as a key for recovery. SJ-02 and Esfip-02 showed lower flooding tolerance and recovery, while TSH-1188 and Pará exhibited higher resilience. [ABSTRACT FROM AUTHOR]

This study evaluated the side-cleft grafting in native species of the genus Piper (Piper aduncum L., Piper hispidum Sw., and Piper tuberculatum Jacq.) with BRS Kottanadan pepper cultivar as rootstocks (Experiment 1). The top-cleft grafting was evaluated in native species Piper arboreum Aubl., P. aduncum, and P. tuberculatum with Balankotta pepper cultivar as graft using black pepper cv. Bragantina (Experiment 2). Black pepper cv. Bragantina autograft was considered as control. The rootstock P. tuberculatum showed initial incompatibility with the cv. Bragantina, with survival of about 34.8% (side) and 62.5% (top) and total inhibition of graft shooting. The side and top graft on P. aduncum resulted in 84.0 and 47.5% of survival, respectively. The JIP-test parameters indicated better photochemical efficiency in the species grafted using the method of side-cleft grafting. Finally, the initial compatibility was associated with greater survival, shooting, and better energy flow through the electron transport chain. [ABSTRACT FROM AUTHOR]

Analyzes results from the final clinical examinations of two separate campuses of the University of the West Indies that use two different learning approaches. Concludes that, except for a few isolated cases, there were no statistically significant differences between the performance of the traditional group and the problem based learning (PBL) group. (Author/NB)

Objective: We explored the prescribing patterns of physicians in North Trinidad in treating upper respiratory tract infections (URTI) in paediatric patients and the appropriateness of drugs prescribed.Methods: A retrospective observational study was conducted, with a sample size of 523 paediatric patients, diagnosed with an URTI during the period of June 2003 to 22 June 2005. The study was conducted at five Primary Health Care Facilities in North Trinidad.Results: The three most frequent URTIs diagnosed were non-specific URTI, common cold, and acute tonsillitis in rank order. Four patterns of prescribing were identified, (1) no drug therapy [1.9%]; (2) antibiotic therapy alone [6.1%]; (3) antibiotic and symptomatic therapy [53.0%]; and (4) symptomatic therapy alone [39.0%]. The, most frequently prescribed antibiotics were penicillins (amoxicillin [46.3%] and amoxicillin/clavulanate [5.3%]) and a macrolide (erythromycin [6.1%]). The three symptomatic agents most frequently prescribed were paracetamol [40.1%]; diphenhydramine [29.1%]; and normal saline nasal drops [14.2%]. In 112 cases with swab analyses done, of these, 98.2% revealed a growth of commensals only, while 1.8% grew pathogenic micro-organisms. Of the cases showing commensal growth only, 84.6% were treated with an antibiotic, 14.5% were treated with symptomatic agents alone and 0.9% received no drug therapy at all. Conclusions: A large proportion of paediatric patients diagnosed with an URTI in North Trinidad was prescribed antibiotics although not indicated The inappropriate use of antibiotics can potentiate the worldwide trend of antimicrobial resistance.