In-situ extraction and impregnation of black walnut husk into polyethylene film using supercritical carbon dioxide with an ethanol modifier

Walnuts are commonly cultivated for their kernel, which is a rich source of antioxidant phenolic compounds. The husk likewise contains antioxidant and antimicrobial compounds, but is typically discarded without further processing. Antioxidant compounds are useful in creating active packaging films, but typically decompose at melt extrusion temperatures in polymer processing. Due to carbon dioxide's low critical point and ability to swell polymer films, supercritical carbon dioxide may be used to impregnate phenolic compounds into polymers. For this study, a novel technique is used to simultaneously produce walnut husk extracts and impregnate the extract into polymer films in the same batch extractor using supercritical carbon dioxide with a 15 wt-% ethanol modifier at 60°C at 19.4 MPa. The effect of varying the loading of walnut husk in the extractor upon impregnation mass was evaluated with the impregnation mass of the film increasing with walnut husk loading. It was determined by FTIR, as well as the reduction of the protein cytochrome c, that antioxidant compounds may be extracted from walnut husks and impregnated into low-density polyethylene film (LDPE) by this technique.

The relationship between sagittal hoof conformation and hindlimb lameness in the horse

BACKGROUND

Lameness can be multifactorial and may result from the accumulation of multiple seemingly unrelated causes. The identification of factors associated with lameness could be one method to decrease incidence of lameness and prolong the equine athlete's competitive life.

OBJECTIVES

To determine if there is an association between hoof balance in the sagittal plane and hindlimb lameness.

STUDY DESIGN

Case-control study.

METHODS

Eighty client-owned horses with hindlimb lameness (cases) and 80 horses with no detectable hindlimb lameness (controls) were prospectively enroled following lameness evaluation as either cases (lameness localised with regional anaesthesia) or controls (no hindlimb lameness). Lameness cases were divided based on location (stifle, tarsus, proximal metatarsus and other sites). Lateromedial radiographs were performed on hind hooves and plantar angle of the distal phalanx (PADP) was determined. The prevalence of negative/neutral PADP and median PADPs were calculated. Conditional logistic regression and Wilcoxon signed rank tests were used to analyse PADPs, and odds ratios were calculated. Significance was set at P<0.05.

RESULTS

The mean PADP was significantly smaller in cases compared to controls. The mean PADP was significantly smaller in horses with lameness localised to tarsus and proximal suspensory, but not the stifle. Lameness in horses was associated with a negative/neutral PADP (Odds ratio [OR] 3.87, 95% confidence interval [95% CI] 1.97-7.61, P<0.01), with lameness localised to the tarsus (OR 4.98, 95% CI 1.34-18.54, P = 0.01) and proximal suspensory (OR 5.16, 95% CI 1.11-23.89, P = 0.03) being associated with a negative/neutral PADP.

MAIN LIMITATIONS

It is unknown whether the negative/neutral PADP contributed to lameness or lameness resulted in lower PADP.

CONCLUSIONS

Horses with hindlimb lameness localised to the distal tarsus and proximal metatarsus, but not the stifle, were more likely to have negative/neutral PADPs. Corrective farriery to improve PADP may be investigated further as one component in the treatment of hindlimb lameness localised to regions proximal to the foot. The Summary is available in Portuguese - see Supporting Information.