15 research outputs found
Photoelectrochemical and Photovoltaic Properties of p–n Cu<sub>2</sub>O Homojunction Films and Their Photocatalytic Performance
The
improvement of photoinduced charge separation is the key for
light-harvesting systems in both photovoltaic and photoelectrochemical
solar cells. In this study, the charge separation efficiency has been
modulated through varying the magnitude of interfacial electric field
in p–n Cu<sub>2</sub>O homojunction films prepared by simple
electrodeposition method. The photoelectrochemical and surface photovoltage
measurements were used to investigate the behaviors of photoinducded
charge carriers in different p–n Cu<sub>2</sub>O homojunction
films. The results confirmed that the p–n Cu<sub>2</sub>O homojunction
film which exhibited the highest charge separation efficiency resulted
in the highest activity in photocatalytic reduction of methyl viologen.
These implied that it is possible to achieve high charge separation
efficiency via constructing a large magnitude of interfacial electric
field within a semiconductor using a simple electrodeposition method
Self-decontaminating properties of fluorinated copolymers integrated with ciprofloxacin for synergistically inhibiting the growth of <i>Escherichia coli</i>
<div><p>In this paper, copolymers composed of antibacterial monomer containing ciprofloxacin, methyl methacrylate (MMA), and 2-perfluorooctylethyl methacrylate (FMA) were prepared, and the surface properties and antibacterial performance of the copolymers and blends-mixed PMMA were investigated. Surface characterization using dynamic contact angle measurement and X-ray photoelectron spectroscopy showed that anti-adhesive fluorinated moieties and antimicrobial moieties were highly concomitant on the material surface. All the copolymers and blends films exhibited excellent antibacterial properties. It was found that the fluorinated antibacterial copolymers showed significantly enhanced antibacterial efficiency toward <i>Escherichia coli</i> bacterium, and even markedly prevented the formation of biofilm for long term. The PMMA films blended with fluorinated antibacterial polymer also show similar results. In contrast, the common copolymer without fluorinated units cannot effectively resist bacterial adhesion, proliferation, and prevent biofilm formation. The desirable antibacterial polymer prohibiting the biofilm formation performance of copolymer with special push-me/pull-you structure which weaken the interaction among polymer chains resulted in the more easy segregation of ciprofloxacin on surface in real environment by the help of synergistic effect of fluorinated units, potentially enabling the design of new self-decontaminating biomaterials for control biofouling.</p></div
Changes in chlorophyll contents during Alternaria disease development promoted by chilling stress pre-treatment.
<p>a: the control cotton plants sustained growing at optimal temperature of 28/20°C. b, c, d: Cotton plants performed with chilling stress pre-treatments at 20/16°C, 16/12°C, 12/8°C for 3 days respectively, then inoculated with 1.2×10<sup>4</sup> conidial/mL inoculum suspension of <i>A. alternata</i> isolate A1, and returned to grow at 28/20°C. All collected data (mean ± standard deviation SD with 6 replicates) were presented as relative values to the chlorophyll contents (SPAD unit) at −3 d (100% chlorophyll content = 41.5 for XLZ13 and 44.0 for XLZ33 leaves, respectively). The chilling stress pre-treatment period was indicated by time points from −3 to 0, and the period after inoculation was indicated by time points from 0 to 15.</p
Influences of chilling stress pre-treatments performed with various durations of chilling stress at 16/12°C on occurrence and development of Alternaria disease.
<p>Cotton seedlings were pre-treated with various duration of chilling stress at 16/12°C, then inoculated with <i>A. alternata</i> isolate A1, and removed to grow at optimal temperature of 28/20°C; Different letters behind the disease index indicate significant difference with the <i>P</i> value of 0.05. The first letters indicate the comparison among various duration of chilling stress at 16/12°C and the second letters indicate the comparison between XLZ13 and XLZ33.</p
Effect of Surface Compositional Heterogeneities and Microphase Segregation of Fluorinated Amphiphilic Copolymers on Antifouling Performance
In
this paper, a series of fluorinated amphiphilic copolymers composed
of 2-perfluorooctylethyl methacrylate (FMA) and 2-hydroxyethyl methacrylate
(HEMA) monomers were prepared, and their surface properties and antifouling
performance were investigated. Bovine serum albumin (BSA) and human
plasma fibrinogen (HFg) were used as model proteins to study protein
adsorption onto the fluorinated amphiphilic surfaces. All the fluorinated
amphiphilic surfaces exhibit excellent resistant performance of protein
adsorption measured by X-ray photoelectron spectroscopy (XPS). The
surface compositional heterogeneities on the molecular scale play
an important role in the antifouling properties. It was found that
the copolymers exhibited better antifouling properties than the corresponding
homopolymers did, when the percentage of hydrophilic hydroxyl groups
is from 4% to 7% and the percentage of hydrophobic fluorinated moieties
is from 4% to 14% on the surface. In addition, the protein molecular
size scale and the pattern of microphase segregation domains on the
surface strongly affect the protein adsorption behaviors. These results
demonstrate the desirable protein-resistant performance from the fluorinated
amphiphilic copolymers and provide deeper insight of the effect of
surface compositional heterogeneity and microphase segregation on
the protein adsorption behaviors
Changes in MDA content during Alternaria disease development promoted by chilling stress pre-treatment.
<p>a: the control cotton plants sustained growing at optimal temperature of 28/20°C. b, c, d: Cotton plants performed with chilling stress pre-treatments at 20/16°C, 16/12°C, 12/8°C for 3 days respectively, then inoculated with 1.2×10<sup>4</sup> conidial/mL inoculum suspension of <i>A. alternata</i> isolate A1, and returned to grow at 28/20°C. All collected data (mean ± standard deviation SD with 6 replicates) were presented as relative values to the malondialdehyde contents at −3 d (100% MDA content = 22.4 nmol/gFW for XLZ13 and 21.8 nmol/gFW for XLZ33 leaves, respectively). The chilling stress pre-treatment period was indicated by time points from −3 to 0, and the period after inoculation was indicated by time points from 0 to 15.</p
Appearance of Alternaria disease on cotton leaves pre-treated by chilling stress with various low temperatures.
<p>Chilling stress pre-treatments were performed with various low temperatures for 3 days. Then the pre- treated cotton leaves were inoculated with 1.2×10<sup>4</sup> conidial/mL inoculum suspension of <i>A. alternata</i> isolate A1 by slightly brushing method and returned to grow at optimal temperature of 28/20°C. The mock inoculations were performed with sterilized water. Presented pictures photographed at 15 days after inoculation.</p
Changes in soluble protein contents during Alternaria disease development promoted by chilling stress pre-treatment.
<p>a: the control cotton plants sustained growing at optimal temperature of 28/20°C. b, c, d: Cotton plants performed with chilling stress pre-treatments at 20/16°C, 16/12°C, 12/8°C for 3 days respectively, then inoculated with 1.2×10<sup>4</sup> conidial/mL inoculum suspension of <i>A. alternata</i> isolate A1, and returned to grow at 28/20°C. All collected data (mean ± standard deviation SD with 6 replicates) were presented as relative values to the soluble protein content at −3 d (100% soluble protein content = 24.8 mg/gFW for XLZ13 and 27.5 mg/gFW for XLZ33 leaves, respectively). The chilling stress pre-treatment period was indicated by time points from −3 to 0, and the period after inoculation was indicated by time points from 0 to 15.</p
Appearance of Alternaria disease on cotton leaves pre-treated by various durations of chilling stress at 16/12°C.
<p>Various durations of chilling stress pre-treatments were performed at 16/12°C. Then the pre-treated cotton leaves were inoculated with 1.2×10<sup>4</sup> conidial/mL inoculum suspension of <i>A. alternata</i> isolate A1 by slightly brushing method and returned to grow at optimal temperature of 28/20°C. The mock inoculations were performed with sterilized water. Presented pictures photographed at 15 days after inoculation.</p
Influences of chilling stress pre-treatments performed with various low temperatures on occurrence and development of Alternaria disease.
<p>Cotton seedlings were pre-treated with chilling stress for 3 days, then inoculated with <i>A. alternata</i> isolate A1, and removed to grow at optimal temperature of 28/20°C; Different letters behind the disease index indicate significant difference with the <i>P</i> value of 0.05. The first letters indicate the comparison among different temperatures of chilling stress pre-treatment and the second letters indicate the comparison between XLZ13 and XLZ33.</p