Ultrastructural and three‐dimensional study of post‐LASIK ectasia cornea

INTRODUCTION: Post‐laser in situ keratomileusis (LASIK) corneal ectasia is a serious late postoperative complication. Here, we report the ultrastructural features of the post‐LASIK cornea of two patients. METHODS: Two normal corneas (age 24 and 37 years old) and two post‐LASIK ectaic corneas from two patients (A and B) were studied. The “patient A” (age 27 years) underwent penetrating keratoplasty and “patient B” (age 31 years) underwent deep‐anterior lamellar keratoplasty. The excised corneas were processed for light and electron microscopy. A total of 120 images for three‐dimensional (3D) reconstruction were taken by using the software “Recorder” and using a bottom mounted camera “Quemesa” attached to a JOEL 1400 transmission electron microscope. The 3D images were constructed using “Visual Kai” software. RESULTS: In the post‐LASIK cornea, the hemidesmosomes, the basement membrane, and Bowman”s layer were abnormal. The stromal lamellae were thin and disorganized. The collagen fibrils (CFs) diameter and interfibrillar spacing had decreased. Aggregated microfibrils were present in the Bowman's layer and all parts of the stroma. A large number of microfilaments were present at the detachment end of the flap and residual stroma. The 3D images showed the presence of collagen microfibrils and proteoglycans (PGs) within the CF of the normal and post‐LASIK cornea. The collagen microfibrils and PGs within the CFs had degenerated in the post‐LASIK cornea. CONCLUSION: Collagen microfibrils and PGs within the CFs were degenerated, leading to the degeneration of CFs, followed by the disorganization of lamellae in post‐LASIK cornea. The CFs diameter and interfibrillar spacing decreased. Microsc. Res. Tech. 77:91–98, 2014. © 2013 Wiley Periodicals, Inc.     

Dural sinus thrombosis: CT and MR imaging of different stages

Cerebral dural sinus thrombosis remains an uneasy clinical diagnosis because it may present with a spectrum of nonspecific manifestations. CT and MR findings have been described to help recognize this entity. We report here a case with different stages of thrombosed superior sagittal and right transverse dural sinuses demonstrated by CT and MR imaging.     

An investigation of the effect of thermal cycling on plasma‐sprayed zirconia/NiCoCrAlY thermal barrier coating

The microstructural change, crack initiation and spallation of a vacuum plasma sprayed (VPS) thermal barrier coating on an INCONEL‐738 superalloy substrate were investigated after successive 300 h thermal cycles at 1050°C. The coating was characterised using Raman spectroscopy, scanning electron microscopy (SEM) energy dispersive X‐ray analysis (EDX) and Auger electron spectroscopy (AES). Localised micro‐cracks at the yttrium (III) oxide stabilised zirconium (IV) oxide (YSZ) ceramic coating/thermally grown oxide (TGO) interface were observed after 8 cycles. Spallation of the YSZ coating occurred after approximately 21 cycles. Significant amounts of the elements titanium, tantalum and chromium were found within the TGO together with the formation of nickel, cobalt and chromium‐rich oxides at this TGO/YSZ interface.     

Dynamic accumulation of 4-desmethylsterols and phytostanols during ripening of Tunisian Meski olives (Olea europea L.)

Eleven 4-desmethylsterols and two phytostanols were identified by GC–MS during the ripening of Meski olive. The maximum levels of 4-desmethylsterols (1300 mg/100 g oil) and phytostanols (7.5 mg/100 g oil) were reached at the 26th week after the flowering date (WAFD) of fruit. β-Sitosterol (72–86% of total 4-desmethylsterols) was the major 4-desmethylsterols during the maturity of fruit, while sitostanol was the predominant phytostanols (75–85% of total phytostanols). Δ5-Avenasterol (2–18%) and campesterol (1.6–4%) were the second and the third 4-desmethylsterol levels detected, respectively, during the ripening of Meski olive. The levels of campestanol varied from 15% to 25% of phytostanols. The rate of accumulation of those compounds occurred before 30th WAFD. Some of these compounds (4-desmethylsterols and phytostanols) showed nearly the same profile during the ripening of Meski olive which could be linked to the relation between these compounds during their biosynthetic pathway.     

The potential use of irradiation to extend the shelf-life of clams (Ruditapes decussatus) during live storage: effect on bacterial and biochemical profiles

Changes in microbiological and biochemical quality of clams ( Ruditapes decussatus ) subjected to low doses of gamma irradiation (0.5 and 1 kGy) were investigated during alive storage, at 5 °C. The mortality rate was significantly lower for irradiated clams compared with the control. In the same way, ammonia content was lower for irradiated clams (especially 1 kGy irradiated group). Considerable levels of total mesophiles, coliforms, staphylococcus, faecal streptococcus and Escherichia coli were detected in the control and irradiation had immediately reduced these charges; all bacteria studied experienced a 1- to 3-log reduction following 1 kGy irradiation. At the last day of storage, irradiated groups showed a noticeable reduction in the bacterial counts, whereas the mesophiles, staphylococcus and coliform germs were abundant in the control group (6.3, 2 and 1.7 log CFU g⁻¹, respectively). Irradiation doses up to 1 kGy had not an immediate effect on fatty acids composition ( P  > 0.05) and lipid profile was better in irradiated samples, where polyunsaturated fatty acid fraction was maintained throughout storage using irradiation. Also, sodium dodecyl sulphate-polyacrylamide gel electrophoresis revealed minor changes in proteins bands between different samples. These results demonstrated that 1 kGy irradiation appeared to be the optimum dose for treating alive clams ( R. decussatus ), through improving the microbial quality and alleviating biochemical changes during refrigerated storage.     

Generalization of association rules through disjunction

Several efforts were devoted to mining association rules having conjunction of items in premise and conclusion parts. Such rules convey information about the co-occurrence relations between items. However, other links amongst items—like complementary occurrence of items, absence of items, etc.—may occur and offer interesting knowledge to end-users. In this respect, looking for such relationship is a real challenge since not based on the conjunctive patterns. Indeed, catching such links requires obtaining semantically richer association rules, the generalized ones. These latter rules generalize classic ones to also offer disjunction and negation connectors between items, in addition to the conjunctive one. For this purpose, we propose in this paper a complete process for mining generalized association rules starting from an extraction context. Our experimental study stressing on the mining performances as well as the quantitative aspect proves the soundness of our proposal.