Correlation between wing bone microstructure and different flight styles: The case of the griffon vulture (gyps fulvus) and greater flamingo (phoenicopterus roseus)

Flying is the main means of locomotion for most avian species, and it requires a series of adaptations of the skeleton and of feather distribution on the wing. Flight type is directly associated with the mechanical constraints during flight, which condition both the morphology and microscopic structure of the bones. Three primary flight styles are adopted by avian species: flapping, gliding, and soaring, with different loads among the main wing bones. The purpose of this study was to evaluate the cross-sectional microstructure of the most important skeletal wing bones, humerus, radius, ulna, and carpometacarpus, in griffon vultures (Gyps fulvus) and greater flamingos (Phoenicopterus roseus). These two species show a flapping and soaring flight style, respectively. Densitometry, morphology, and laminarity index were assessed from the main bones of the wing of 10 griffon vultures and 10 flamingos. Regarding bone mineral content, griffon vultures generally displayed a higher mineral density than flamingos. Regarding the morphology of the crucial wing bones involved in flight, while a very slightly longer humerus was observed in the radius and ulna of flamingos, the ulna in griffons was clearly longer than other bones. The laminarity index was significantly higher in griffons. The results of the present study highlight how the mechanics of different types of flight may affect the biomechanical properties of the wing bones most engaged during flight.     

Effect of ethylene glycol dimethacrylate on swelling and on metformin hydrochloride release behavior of chemically crosslinked pH–sensitive acrylic acid–polyvinyl alcohol hydrogel

Background

The present work objective was to prepare and to observe the effect of ethylene glycol dimethacrylate on swelling and on drug release behavior of pH-sensitive acrylic acid–polyvinyl alcohol hydrogel.

Methods

In the present work, pH sensitive acrylic acid–polyvinyl alcohol hydrogels have been prepared by free radical polymerization technique in the presence of benzoyl peroxide as an initiator. Different crosslinker contents were used to observe its effect on swelling and on drug release. Dynamic and equilibrium swelling studies of prepared hydrogels were investigated in USP phosphate buffer solutions of pH 1.2, 5.5, 6.5 and 7.5 with constant ionic strengths. Hydrogels were evaluated for polymer volume fraction, solvent interaction parameter, molecular weight between crosslinks, number of links per polymer chain, diffusion coefficient, sol–gel fraction and porosity. To demonstrate the release pattern of the drug, zero-order, first-order, higuchi and korsmeyer-peppas models were applied. Quality and consistency of hydrogels was examined by FTIR and surface morphology of hydrogels was examined by SEM.

Results

Decrease in swelling and in drug release was seen by increasing content of ethylene glycol dimethacrylate. A remarkable high swelling was observed at high pH indicating the potential of this hydrogel for delivery of drugs to intestine. By increasing the concentration of ethylene glycol dimethacrylate, porosity decreased. Order of release was observed first order in all cases and the mechanism was non–fickian diffusion. FTIR confirmed the formation of network. SEM results showed the incorporation of drug.

Conclusion

The prepared hydrogels can be suitably used for targeted drug delivery to the intestine.     

Risk of hepatocellular carcinoma after hepatitis C virus cure

Hepatitis C virus(HCV)is a significant cause of hepatocellular carcinoma(HCC).The direct-acting antivirals marked a new era of HCV therapy and are associated with greater than 95%cure rate.Successful treatment of chronic hepatitis C greatly reduces the risk of HCC.A proportion of patients,especially those with pre-existing cirrhosis,remain at risk for HCC despite sustained virologic response(SVR).Diabetes mellitus,hepatic steatosis,alcohol consumption and lack of fibrosis regression are associated with risks of HCC after HCV cure.Noninvasive modalities such as aspartate aminotransferase to platelet ratio index and fibrosis-4 index and transient elastography have been used to monitor hepatic fibrosis.More recently,various fibrosis scores have been combined with clinical parameters and other novel biomarkers to predict risks of HCC for patients who achieved SVR.These models still need to be validated and standardized prior to applying to routine clinical care.     

Contrast-Enhanced Spectral Mammography and tumor size assessment: a valuable tool for appropriate surgical management of breast lesions

Purpose

To compare the accuracy of Contrast-Enhanced Spectral Mammography (CESM), MG, US, and breast MRI in estimating the size of breast lesions requiring surgery. The postoperative histology size of the lesion was used as the gold standard.

Material and methods

Two hundred thirty-three non-benign lesions in 189 patients were included in the analyses. All the selected patients underwent CESM and at least one other conventional diagnostic exam (US, MG, or MRI). Subsequently, all the patients underwent surgery preceded by cytological/histological examination. The largest diameter of the lesion at imaging was measured by a radiologist with more than 10 years’ experience and then compared with the size of the lesion in the histological sample at the surgery (gold standard).

Results

Among the 233 breast lesions, 196 were evaluated with US, 206 with MG and 160 with MRI. We found no statistically significant differences between size measurements using CESM and MRI compared with the measurements at the surgery (p value 0.63 and 0.51), whereas a significant difference was found for MG and US (p?<?0.001).

Conclusion

CESM is a reliable method for estimating the size of breast lesions: its performance seems superior to US and MG and comparable to MRI.