Investigation of nanovesicle liposome powder production from soy lecithin by spray drying

ABSTRACT

Aiming to produce stable nanosize liposome vesicles (～100?nm), in a powder form, this study investigated the use of combined microfluidization–spray drying processes, using lactose as a stabilizing agent for vesicles during the process of dehydration. To determine the effective amount of lactose for stabilization, the vesicles were prepared at three different ratios (1:1, 1:3, and 1:5) of lecithin:lactose. The physicochemical properties of the nanoliposome powder and its reconstituted solution with water were evaluated over a storage period of 90 days at water activity below 0.3. The results demonstrated that upon addition of appropriate amount of lactose (1:3 or 1:5 of lecithin:lactose ratio), the aggregation of nanoliposomes was prevented and their size was maintained at lower than 130?nm during storage. Peroxide values of all nanoliposome formulations during the storage period remained below 3?meq/kg and there was no change in L*, a*, b* color parameters. The X-ray photoelectron spectroscopy analysis showed over-representation of lecithin on the power particle surface as compared to the bulk composition.     

Induction of p34cdc2 in mouse parotid glands upon activation of beta1-adrenergic receptors

The element pSAM2 from Streptomyces ambofaciens integrates into the chromosome through site-specific recombination between the element (attP) and the chromosomal (attB) sites. These regions share an identity segment of 58bp extending from the anti-codon loop through the 3' end of a tRNA(Pro) gene. To facilitate the study of the attB site, the int and xis genes, expressed from an inducible promoter, and attP from pSAM2 were cloned on plasmids in Escherichia coil. Compatible plasmids carrying the different attB regions to be tested were introduced in these E. coli strains. Under these conditions, Int alone could promote site-specific integration; Int and Xis were both required for site-specific excision. This experimental system was used to study the sequences required in attB for efficient site-specific recombination. A 26 bp sequence, centred on the anti-codon loop region and not completely included in the identity segment, retained all the functionality of attB; shorter sequences allowed integration with lower efficiencies. By comparing the 26-bp-long attB with attP, according to the Lambda model, we propose that B and B', C and C' core-type Int binding sites consist of 9 bp imperfect inverted repeats separated by a 5 bp overlap region.     

Picosecond absorption recovery of diphenyl butadiene

Absorption recovery lifetimes of diphenyl butadiene in benzene, cyclohexanol, propylene glycol, and 1, 2-dichloroethane are reported. Recovery lifetimes as short as 65 ps suggest the utility of this compound in UV laser mode-locking applications.     

Reoperations of total hip prosthesis with acetabular reconstruction using bone allografts]

Detachment of the acetabular segment is the most important long-term problem with total hip prostheses. We analyzed long-term outcome in our first 48 acetabular reconstructions with cryopreserved allografts. Among the 48 hips operated on with this technique, 38 were reassessed after a mean follow-up of 7 years 3 months (range 5 years-9 years 6 months). Mean age of the population at surgery was 63 years. There were two predominant etiologies: sequelae of chronic hip luxation and primary osteoarthrosis of the hip. In 10 cases with massive destruction, the Müller ring was used to stabilize the allograft. Results were assessed at 6 months, 2 years, 4 years and at longest follow-up using the Merle d'Aubigné clinical assessment scale. For the radiographic assessment, the Ranawat criteria were used to evaluate the alignment of the reconstruction. Clinically, patient comfort was improved in all cases with significant pain relief. Radiologically, mean acetabular ascention was 5 mm and mean medialization was 3.5 mm. A rim was observed in 24 cases including 19 measuring less than 2 cm. Acetabular loosening was evidenced in the 5 other cases where the rim measured more than 2 mm. In 4 of these 5 cases, the acetabulum had migrated to a new setting. The radiographic image then remained unchanged. Analysis of our 38 first cases showed that bone allografts with cimented acetabulum, sometimes with a stabilizing ring, is one of the possible solutions for difficult acetabular reconstructions. However, after a 7 years 3 months follow-up, we have had five (13%) aseptic displacements including one case requiring reoperation. In the 33 stable joints (87%) with good results reconstruction has achieved a nearly perfect anatomic position, similar to first intention arthroplasty with the use of perfectly stabilized bone grafts with a maximal acetabular surface. Our follow-up is longer than most published in the literature. However, the migration rate of 13% it is still too short to draw any conclusion concerning the long-term outcome in our patients, despite their older age and reduced physical activity compared with primary hip arthroplasty patients.     

Analytical study of the microdisk's resonant modes coupling with a waveguide based on the perturbation theory

An analytical method for the calculation of the coupling between a microdisk and a waveguide is presented. The theoretical analysis is based on the perturbation theory well known in integrated optics. Only whispering-gallery modes with high quality factor are considered to be propagating in this study when the microresonator is used as a laser structure. The influence of the distance disk/waveguide is investigated. These results are compared with calculations obtained with a two-dimensional finite-difference time domain needing more computational requirements. A good agreement between both methods is shown.     

Body composition in systemic lupus erythematosus

Bovine enamel is commonly used in enamel bonding studies, therefore, a familiarity with some aspects of bovine enamel bonding are important in order to evaluate the studies. Bovine enamel has the advantages of easy attainability and similar microstructure to human enamel. In this study the strength of the enamel bond using an orthodontic adhesive was compared between deciduous bovine, permanent bovine, and human enamel, as well as, the effect on bond strength of multiple rebonding to bovine enamel. This study found that the bond strength to bovine enamel was 21% to 44% weaker than to human enamel, and the bond strength to deciduous bovine enamel was significantly greater than to permanent bovine enamel. Either all deciduous or all permanent bovine incisors should be used, or permanent and deciduous bovine incisors evenly distributed in sample groups. Bovine enamel was rebonded five times without significantly affecting bond strength, thus, bovine enamel can be reused in bonding studies without significantly affecting the results.