Improving the Industrial Practice of Reactive Washing of Cork Stoppers Using a Fractional Factorial Design.

Reactive washing (RW) is a key process for disinfecting, purifying, and bleaching of cork stoppers to seal bottles with alcoholic beverages. Excessively severe treatment conditions deteriorate the surface properties of cork stoppers and must be strictly controlled. In this study, the conventional RW of natural cork stoppers was optimized employing a fractional factorial design. The RW variables (H2O2 and NaOH concentrations, oxidation time, and washing water volume) were correlated with the final ISO brightness of the stoppers. A three-level and four-factor fractional factorial design within the response surface methodology approach allowed a quadratic model to predict the process response, where the H2O2 concentration is the variable with the highest response (ISO brightness), followed by the NaOH concentration. The model obtained was validated, allowing the optimization of the process with savings of 37% in the concentration of H2O2 and 33% in the concentration of NaOH and volume of washing water, without deteriorating the final appearance of the stoppers. In addition, the less severe treatment of stoppers under optimized conditions led to less degradation of their surface, thus favoring the receptivity to functional coatings.

Structural Features of Cork Dioxane Lignin from Quercus suber L.

The dioxane lignin was isolated from extractives- and suberin-free cork (Quercus suber L.) by a modified acidolytic procedure and submitted to structural analysis by permanganate oxidation, analytical pyrolysis coupled with gas chromatography and mass spectrometry (Py-GC-MS), liquid- and solid-state nuclear magnetic resonance (NMR) spectroscopy, and Fourier transform infrared (FTIR) spectroscopy. The molecular weight (Mw = 2500 Da) was assessed by size exclusion chromatography (SEC). The results obtained show that the cork lignin is of syringyl (S)/guaiacyl (G) type with a small proportion of p-hydroxyphenyl (H) units (S:G:H molar ratio of 23:72:5). Among a dozen detected lignin structures, those linked by ether bonds, such as ß-O-4' (38 mol %) and 4-O-5' (5 mol %), were the most abundant. The frequency of occurrence of ß-5', ß-ß', 5-5', tetrahydrofuran type, and structures arising from the condensation with concomitant procyanidins was assessed. Ferulates were the only cinnamic structure detected in the cork dioxane lignin.

An observational retrospective study of odontogenic cyst´s and tumours over an 18-year period in a Portuguese population according to the new WHO Head and Neck Tumour classification / Un estudio observacional retrospectivo de quistes y tumores odontogénicos durante un período de 18 años en una población portuguesa según la nueva clasificación de la OMS para los tumores de cabeza y cuello

Background: Odontogenic cysts and tumours of the jaws represent one of the most prevalent groups of oral-maxillofacial lesions. We aimed to evaluate the clinical and pathological characteristics of a cohort of odontogeniccysts (OC) and odontogenic tumours (OT) of the jaws in a Portuguese population.Material and Methods: This observational retrospective study analysed patients diagnosed with either an OC orOT of the jaws at a central hospital of Oporto, Portugal, between 1988 and 2006. Data collected from patients’files included demographic, clinical, radiological and histopathological information. Recurrence was evaluatedusing univariate and multivariate analysis.Results: The sample consisted of 397 patients, 231 males (58.2%) and 166 females (41.8%), with a mean-ageof 36.7±17 years. Twenty-seven patients (6.8%) presented with more than one lesion providing a total of 433lesions. There were 396 (91.5%) OC, mostly represented by radicular cysts (n=257;59.4%), dentigerous cysts(n=79;18.2%), or odontogenic keratocysts (n=50;11.5%). There were 37 (8.5%) OT, mostly represented by amelo-blastomas (n=16;3.7%), and odontomas (n=9;2.1%). The most common initial clinical manifestation was swelling (n=224;51.7%). Recurrence was observed in 30 cases (6.9%), mostly in ameloblastomas (n=6;37.5%) and odontogenickeratocysts (n=12;24%). In the multivariate analysis the diagnosis classification of the lesion was the only indepen -dent and significant variable related with the recurrence (P=0.04).Conclusions: Radicular cysts were the most commonly occurring type of OC and ameloblastomas the most com-monly occurring OT. Amelobastomas and odontogenic keratocysts were the lesions with the highest rates of recur-rence. This large sample provides useful information about the frequency profile and characteristics of OC and OTover a period of 18 years, allowing valuable comparison with data from other countries.(AU)