Evaluation of electrospun lignin/polyvinyl alcohol/cellulose nanofiber mats

Polymeric electrospun nanofiber mats have recently emerged as a promising alternative to conventional wound dressings for non-healing wounds. Its large surface area, porosity and scalability are only a few of the promising characteristics of electrospun nanofibers.  Nanocellulose, separated from biomass, have also proven a suitable reinforcement to these electrospun nanofibers, giving them stability and strength. Lignin has shown to possess antimicrobial and antioxidant activity, that could aid the healing process. In this project, kraft lignin, polyvinyl alcohol (PVA) and (2,2,6,6-tetramethylpiperidine-1-oxyl radical)-mediated oxidised cellulose nanofibers (CNF) has been electrospun into nanofiber mats and their applicability as a wound dressing was investigated. The electrospinning process was evaluated at different ratios of PVA/lignin: CNF, and the obtained nanofiber mats were crosslinked to restrict water solubility. Physical crosslinking was made through a heat treatment and a freeze thawing process. Mechanical properties, swelling capacity and oxygen permeability were evaluated and analysed based on the CNF content of the electrospun solutions, as well as the crosslinking methods used. Results show that the electrospun nanofiber mats where stable in water after a heat treatment at 150 °C and 3 freeze-thawing cycles. These crosslinking methods did not affect the morphology or size of the fibers. However, tensile strength and elastic modulus was improved with it. The addition of 0.1 wt% CNF into the electrospinning solution improved oxygen permeability, mechanical properties, and swelling capacity, which can be attributed to a small fiber diameter and increased crystallinity. However, exceeding that level of CNF deteriorated the same properties because of uneven fibers with beading. This material is showing promising characteristics of a wound dressing, with high oxygen permeability and swelling capacity owing to thin nanofibers and a porous network

The Use of Unoccupied Aerial Systems (UASs) for Quantifying Shallow Coral Reef Restoration Success in Belize

There is a growing need for improved techniques to monitor coral reef restoration as these ecosystems and the goods and services they provide continue to decline under threats of anthropogenic activity and climate change. Given the difficulty of fine-scale requirements to monitor the survival and spread of outplanted branching coral fragments, Unoccupied Aerial Systems (UASs) provide an ideal platform to spatially document and quantitatively track growth patterns on shallow reef systems. We present findings from monitoring coral reef restoration combining UAS data with object-oriented segmentation techniques and open-source GIS analysis to quantify the areal extent of species-specific coverage across ~one hectare of shallow fringing reef over a one-year period (2019–2020) in Laughing Bird Caye National Park, southern Belize. The results demonstrate the detection of coral cover changes for three species (Acropora cervicornis, Acropora palmata, and Acropora prolifera) outplanted around the caye since 2006, with overall target coral species cover changing from 2142.58 to 2400.64 square meters from 2019 to 2020. Local ecological knowledge gathered from restoration practitioners was used to validate classified taxa of interest within the imagery collected. Our methods offer a monitoring approach that provides insight into coral growth patterns at a fine scale to better inform adaptive management practices for future restoration actions both within the park and at other reef replenishment target sites

ERBB3 and intestinal stem cell markers LGR5, EPHB2, CD44s and CD44v6 are over-expressed in colorectal adenomas and adenocarcinomas.

<p>(A): The average expression levels (2^-ΔΔCt) for each gene was calculated relative to beta-2-microglobulin and β-actin expression levels by qRT-PCR in normal colon tissues (n = 54), colorectal adenomas (n = 4) and colorectal adenocarcinomas (n = 54) (mean±s.e.m.). Significant differences (*) were observed compared to control tissues (Paired Student’s T test, p<0.001). (B): Immunohistochemical detection of ERBB3 and EPHB2 in normal colon tissue, adenoma and adenocarcinoma. Scale bar, 50μm.</p

ERBB3 positively correlates with EPHB2 in colorectal cancer cell lines.

<p>(A): The average expression levels (2^-ΔΔCt) of ERBB3 and EPHB2 were calculated relative to beta-2-microglobulin and β-actin expression levels by qRT-PCR in 6 different colorectal cancer cell lines (n = 3, mean±s.e.m.). (B): Positive linear correlation between ERBB3 and EPHB2 expression levels (Pearson correlation test, rho = 0.999, p<0.0001).</p

MUC2+ differentiated colorectal cancer cells are predominantly ERBB3+.

<p>Detection of EPHB2 (green), ERBB3 (red) and MUC2 (grey) by co-immunofluorescence in two representative colorectal cancer samples (DAPI, blue). Note the presence of EPHB2-/ERBB3+ cells (white arrow) that are MUC2-. Scale bar, 50μm.</p

ERBB3 and EPHB2 mark distinct cell populations in colorectal cancer.

<p>(A): Frequency of EPHB2+ and ERBB3+ cells in colorectal cancer (n = 15). (B, C, D, E): Co-immunofluorescent detection of EPHB2 (green) and ERBB3 (red) in representative colorectal cancer samples counterstained with DAPI (blue). Note the presence of one EPHB2-/ERBB3+ cell (white arrow) in a tumour enriched for EPHB2+/ERBB3- cells (B). Note the presence of double negative cells (white arrow) in a tumour containing both EPHB2+/ERBB3- and EPHB2-/ERBB3+ cell populations (D). Scale bar, 50μm.</p

Colorectal tumours maintain tissue organisation similar to normal colon.

<p>Detection of EPHB2 (green) and ERBB3 (red, A and B) by co-immunofluorescence in normal colon (A) and colorectal cancer (B) (DAPI, blue). Scale bar, 50μm.</p

ERBB3+ colorectal cancer cells are predominantly non proliferative in contrast to EPHB2+ cells.

<p>(A and B): Detection of EPHB2 (green), ERBB3 (red) and KI-67 (grey) by co-immunofluorescence in two representative colorectal cancer samples (DAPI, blue). (C): Distribution of P-H3+ proliferative cells within the 4 distinct cell populations in 8 colorectal cancer samples. (D and E) Detection of EPHB2 (green), ERBB3 (red) and P-H3 (grey) by co-immunofluorescence in two representative colorectal cancer samples (DAPI, blue). Scale bar, 50μm.</p

ERBB3 and intestinal stem cell markers LGR5, EPHB2, CD44s and CD44v6 are over-expressed in colorectal cancers.

<p>Quantitative real-time PCR results are expressed relative to matched normal tissue for each adenocarcinoma (n = 50). Inserts show boxplots comparing the absolute values of gene expression in normal (N) and tumour (T) tissues. * Significant difference compared to control tissues (Wilcoxon sign rank test, p<0.001).</p