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This study successfully incorporated a short‐segment fluorine‐containing chain extender (2,2,3,3‐tetrafluoro‐1,4‐butanediol [TF]) into castor oil‐based polyurethane (COPU) to synthesize TF/COPUs. The interactions between TF and COPU components were identified by Fourier transform infrared and X‐ray photoelectron spectroscopies, the results revealed that the increase in the TF content increased the van der Waals forces in CF...CO and the hydrogen bonding force in CF...HN. Atomic force microscopy indicated that the addition of more TF contributed to a higher level of microphase separation in the TF/COPUs. Thermogravimetric analysis showed that the TF component can enhance the thermal resistance of TF/COPUs. Differential scanning calorimetry and dynamic mechanical analysis indicated that the glass transition temperature (Tg) of TF/COPUs increased with the TF content. The stress–strain testing showed that the tensile strength and elongation at break values decreased with the TF content. This tensile behavior may be due to the molecular weight of a TF/COPU decreased with the TF content as evidenced by the gel permeation chromatography results. The hydrolytic degradation tests of dipping TF/COPUs in 3 wt% NaOH solution indicated that TF could lower the surface free energy and enhance the degradation stability of TF/COPUs. [ABSTRACT FROM AUTHOR]

In the field of ophthalmology, postoperative endophthalmitis (POE) is a serious surgical complication, which may lead to poor visual outcome even after the infection has been controlled. In the study, we develop a sustained drug releasing system loaded with levofloxacin which is expected to be effective against common pathogens responsible for POE for at least 7 days after single application at the end of surgery. The results of study showed that the sol–gel transition temperature of the levofloxacin‐loaded chitosan‐gelatin‐based solution was ~34°C. The gelation time of the developed formulation was ~81 s at 34°C. The results showed that the osmolality of developed hydrogel was 304 mOsm/L. The in vitro drug release studies revealed that levofloxacin release from the developed hydrogel displayed a sustained‐release profile. The long‐term antibacterial property of the developed hydrogel has been demonstrated. The biocompatibility of the developed hydrogel was evaluated in vitro. These results suggest that the levofloxacin‐containing hydrogel could be applied to ocular surface at the end of ophthalmic surgery, without the risks of intracameral injection of antibiotics. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 108B:8–13, 2020. [ABSTRACT FROM AUTHOR]

Using the hard clam farms in Yunlin, Taiwan as examples, this study analyzes the effects of culture area, stocking density, and shrimp and fish polyculture on the cost efficiency ( CE) of hard clam farming. A data envelopment analysis ( DEA) is used to estimate the farms' technical efficiency ( TE), allocative efficiency ( AE), and CE values. The findings show that the mean TE, AE, and CE values of hard clam farms are 0.74, 0.57, and 0.43, respectively. The TE value is higher than the AE value, which indicates that cost inefficiency is mainly attributable to poor AE. Tobit regression results suggest that there are positive relationships between CE and both culture area and operator experience. Hard clam stocking density and age of the operators have negative effects on CE. Hard clam culture areas larger than 2 ha and a stocking density of 1.1-1.2 million hard clams per hectare have higher CEs than smaller culture areas and smaller or larger stocking densities. The use of sand shrimp, white shrimp, kuruma shrimp, and grass shrimp for polyculture and the use of milkfish and silver sea bream for polyculture are both associated with high CEs. [ABSTRACT FROM AUTHOR]

Gelatin is an efficient drug delivery vehicle for attaching targeting molecules like phytohemagglutinin erythroagglutinating (PHA-E) and carrying the chemotherapeutic agent gemcitabine (GEM). Fluorescent gelatin nanoparticles (GNPs) conjugated with PHA-E and carrying gemcitabine (GNP–(PHA-E)–GEM) were synthesized by nanoprecipitation for guiding gemcitabine-loaded gelatin nanoparticles to NSCLC by PHA-E targeting. GNPs have a uniform narrow size distribution and spherical shape, and their particle size is about 290 nm. The release rate of gemcitabine from nanoparticles reached the plateau of the curve at approximately 30% within 72 hours. PHA-E conjugated nanoparticles could enhance the cellular accumulation of nanoparticles. The results showed that GNP–(PHA-E)–GEM treatment caused an increase of cell growth inhibition and cytotoxicity on NSCLC cells A-549 and H292. In an Annexin V/PI assay, treatment with GNP–(PHA-E)–GEM could induce apoptosis of cancer cells. Treatment of NSCLC cells with GNP–(PHA-E)–GEM firstly resulted in time-dependent inhibition of epidermal growth factor receptor (EGFR) and Akt phosphorylation. And it also could increase p53 phosphorylation. And then it could decrease Bad phosphorylation and increase Bax. Finally, it could result in enhancing the release of cytochrome c, which thus increases caspase-9 and caspase-3. In conclusion, GNP–(PHA-E)–GEM could induce growth inhibition and cytotoxicity, which was mediated through inhibition of EGFR phosphorylation and the switching on of p53 that causes cell apoptosis of NSCLC cells A-549 and H292. It's significant to conjugate PHA-E for targeting cancer and inhibiting EGFR phosphorylation as it could decrease the dosage of gemcitabine, which reduces side effects on normal tissue. GNP–(PHA-E)–GEM has great potential for NSCLC treatment. [ABSTRACT FROM AUTHOR]