Vegetable oil-based polymeric materials always suffer
from relatively poor performance, such as
lower tensile strength and glass transition temperatures, than petroleum-based
polymeric materials, which greatly limit their practical applications.
In this study, octahydro-2,5-pentalenediol (OPD) was synthesized from
naturally occurring citric acid and used together with castor oil
as the polyol blends for the production of bio-based waterborne polyurethane
(PU) dispersions (PUDs). The effects of the OPD contents on the particle
size and ζ potential of the resulting polyurethane dispersion,
and the thermal stability, mechanical properties, and hydrophilicity
of the resulting polyurethane films were systematically investigated.
Taking advantage of the rigid cyclic structures of the OPD and the
flexible fatty acid chain of castor oil, waterborne polyurethane (WPU)
films with tailorable mechanical performance ranging from elastomeric
polymers to rigid plastics were successfully prepared and characterized.
The tensile strength of the samples increases from 9.5 to 22.3 MPa
with the ratio between OPD and castor oil increasing from 0:10 to
5:5, whereas their elongation at break decreases from 192 to 12%.
A significant increase in the glass transition temperature, transparency,
and anticorrosive properties was observed for the resulting polyurethane
films with increasing the OPD content. However, the thermal stability
of the PU films exhibited a slight decrease as the OPD content increased.
Moreover, the water contact angle exhibited a slight increase for
the polyurethane films prepared from polyol blends compared to the
WPU film prepared from pure castor oil. This work provides a novel
route to tailor the performance of vegetable oil-based waterborne
polyurethanes through the incorporation of rigid cyclic rings into
soft polymer networks.
Porphyrin photosensitizers are widely used in photodynamic therapy (PDT) because of their unique diagnostic and therapeutic functions. However, many factors such as poor water solubility and instability of porphyrin compounds have limited their clinical application. Metal-organic frameworks (MOFs) have the beneficial characteristics of versatility, high porosity, and excellent biocompatibility. Porphyrin-MOF nanomaterials have attracted the attention of researchers because MOFs can effectively suppress the quenching caused by the self-aggregation of porphyrin compounds and promote drug delivery. This article reviews the latest applications of porphyrin-MOF nanomedicine in type II photodynamic therapy by increasing tumour cell oxygen concentration, depleting tumour cell functional molecules and releasing signal molecules. Current potential limitations and future applications are also emphasized and discussed herein.
BackgroundIn southern China, a wild ectomycorrhizal mushroom commonly called “Dahongjun” or “Big Red Mushroom” by the local residents, has been harvested, consumed, and/or exported as an exotic food for many years. Although ecologically and economically important, very little is known about this mushroom, including its diversity and population structure.Methodology and Principal FindingsIn this study, we analyzed 122 samples from five local populations representing the known distribution ranges of this mushroom in southern China. We investigated the genetic diversity and geographic structure of this mushroom using sequences from four DNA fragments. Our analyses identified that this mushroom contained at least three divergent lineages: one corresponds to a recently described species Russula griseocarnosa from southern China and the remaining two likely represent two novel species. While these lineages were prominently structured geographically based on ITS sequences, evidence for ancient and/or recent gene flow was also identified within individual lineages. In addition, a local population from Ailaoshan in central Yunnan Province where 85 of our 122 specimens came from showed clear evidence of recombination.Conclusion and SignificanceThe ectomycorrhizal mushroom “Dahongjun” from southern China is a species complex with at least three divergent lineages. These lineages are largely geographically structured and there is evidence for recombination in nature. Our results indicate mature Dahongjun mushrooms with abundant basidiospores are important for the reproduction of this mushroom in nature and that individual populations of this species should be managed separately.
Dichromate is a widespread contaminant in wastewater,
threatening
the health of humans and other organisms. Therefore, effective detection
and removal of dichromate from water is of great significance. Herein,
a tetraphenylethylene functionalized cationic organic network (CON-LDU2) was constructed via a facile quaternization reaction. CON-LDU2 was successfully integrated with both detection and
removal functionalities toward dichromate. On the one hand, benefiting
from the strong fluorescence, CON-LDU2 was employed as
a chemosensor, it could efficiently and selectively probe Cr2O7
2– in water with “turn-off”
fluorescent response. On the other hand, the cationic skeleton and
free anions inside framework make CON-LDU2 an excellent
adsorbent for Cr2O7
2–, it
could capture Cr2O7
2– from
water with rapid kinetics and high capacity. The kinetic constant
for adsorption of Cr2O7
2– can
reach up to 1.784 g mg–1 min–1, while the capacity is determined as 325 mg g–1. Furthermore, CON-LDU2 displayed good recyclability
and can be reused for at least 5 cycles. Therefore, CON-LDU2 can serve as an ideal candidate not only in detection but also in
removal of Cr2O7
2– in water
medium.
A new kind of block copolymer micelles methoxy polyethylene glycol (mPEG) grafted a-zein protein (mPEG-g-a-zein) was synthesized. The chemical composition of mPEG-g-a-zein was identified with the help of FT-IR and 1 H-NMR. The biohybrid polymer can selfassemble into spherical core-shell nanoparticles in aqueous solution. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to investigate the self-assembled morphology of mPEG-g-a-zein. Dynamic light scattering (DLS) results showed that the particle size of mPEG-g-a-zein was about 90 nm. Moreover, the nanoparticles had a very low critical micelle concentration value with only 0.02 mg/mL. Then, the anticancer drug curcumin (CUR) was encapsulated into the biohybrid polymer micelles. The in vitro drug release profile showed a zero-order release of CUR up to 12 h at 378C. Cell viability studies revealed that the mPEG-g-a-zein polymer exhibited low cytotoxicity for HepG2 cells (human hepatoma cells). Consequently, the mPEG-g-a-zein micelles can be used as a potential nano-carrier to encapsulate hydrophobic drugs and nutrients.
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