50 research outputs found
Spectral Illumination Correction: Achieving Relative Color Constancy Under the Spectral Domain
Achieving color constancy between and within images, i.e., minimizing the color difference between the same object imaged under nonuniform and varied illuminations is crucial for computer vision tasks such as colorimetric analysis and object recognition. Most current methods attempt to solve this by illumination correction on perceptual color spaces. In this paper, we proposed two pixel-wise algorithms to achieve relative color constancy by working under the spectral domain. That is, the proposed algorithms map each pixel to the reflectance ratio of objects appeared in the scene and perform illumination correction in this spectral domain. Also, we proposed a camera calibration technique that calculates the characteristics of a camera without the need of a standard reference. We show that both of the proposed algorithms achieved the best performance on nonuniform illumination correction and relative illumination matching respectively compared to the benchmarked algorithms
Superior Capture of CO<sub>2</sub> Achieved by Introducing Extra-framework Cations into N‑doped Microporous Carbon
We designed and prepared a novel microporous carbon material
(KNC-A-K)
for selective CO<sub>2</sub> capture. The combination of a high N-doping
concentration (>10 wt %) and extra-framework cations, which were
introduced
into carbonaceous sorbents for the first time, endowed KNC-A-K with
exceptional CO<sub>2</sub> adsorption capabilities, especially at
low pressures. Specifically, KNC-A-K exhibited CO<sub>2</sub> uptake
of 1.62 mmol g<sup>–1</sup> at 25 °C and 0.1 bar, far
exceeding the CO<sub>2</sub> adsorption capability of most reported
carbon material to date. Single component adsorption isotherms indicated
that its CO<sub>2</sub>/N<sub>2</sub> selectivity was 48, which also
significantly surpasses the selectivity of conventional carbon materials.
Furthermore, breakthrough experiments were conducted to evaluate the
CO<sub>2</sub> separation capability of KNC-A-K on CO<sub>2</sub>/N<sub>2</sub> (10:90 v/v) mixtures under kinetic flow conditions, and the
obtained CO<sub>2</sub>/N<sub>2</sub> selectivity was as high as 44,
comparable to that predicted from equilibrium adsorption data. Upon
facile regeneration, KNC-A-K showed constant CO<sub>2</sub> adsorption
capacity and selectivity during multiple mixed-gas separation cycles.
Its outstanding low-pressure CO<sub>2</sub> adsorption ability makes
KNC-A-K a promising candidate for selective CO<sub>2</sub> capture
from flue gas. Theoretical calculations indicated that K<sup>+</sup> ions play a key role in promoting CO<sub>2</sub> adsorption via
electrostatic interactions. In addition, we found that HCl molecules
anchored in N-doped carbon have a similar promotion effect on CO<sub>2</sub> adsorption, which contradicts the conventional wisdom that
the neutralization of basic sites by acids diminishes the adsorption
of acidic CO<sub>2</sub> gas
The effect of the combination treatment on key pro-survival kinases.
<p>The combination of taxol and shikonin inhibites the activation of Akt (A), p70S6 (B), and ERKs (C). Human phosphor-kinase array analysis was performed following the manufacturer's instruction. Whole cell lysate from MB231 cells treated with DMSO, taxol (8 nM), shikonin (2.5 μM), or the combination. The normalized intensity for each antibody was plotted. * p<0.05 when compared to the control (DMSO); # p<0.05 when compared to the combination.</p
Highly Sensitive and High-Throughput Method for the Analysis of Bisphenol Analogues and Their Halogenated Derivatives in Breast Milk
The structural analogs
of bisphenol A (BPA) and their halogenated
derivatives (together termed BPs) have been found in the environment,
food, and even the human body. Limited research showed that some of
them exhibited toxicities that were similar to or even greater than
that of BPA. Therefore, adverse health effects for BPs were expected
for humans with low-dose exposure in early life. Breast milk is an
excellent matrix and could reflect fetuses’ and babies’
exposure to contaminants. Some of the emerging BPs may present with
trace or ultratrace levels in humans. However, existing analytical
methods for breast milk cannot quantify these BPs simultaneously with
high sensitivity using a small sampling weight, which is important
for human biomonitoring studies. In this paper, a method based on
Bond Elut Enhanced Matrix Removal-Lipid purification, pyridine-3-sulfonyl
chloride derivatization, and liquid chromatography electrospray tandem
mass spectrometry was developed. The method requires only a small
quantity of sample (200 μL) and allowed for the simultaneous
determination of 24 BPs in breast milk with ultrahigh sensitivity.
The limits of quantitation of the proposed method were 0.001–0.200
μg L<sup>–1</sup>, which were 1–6.7 times lower
than the only study for the simultaneous analysis of bisphenol analogs
in breast milk based on a 3 g sample weight. The mean recoveries ranged
from 86.11% to 119.05% with relative standard deviation (RSD) ≤
19.5% (<i>n</i> = 6). Matrix effects were within 20% with
RSD < 10% for six different lots of samples. The proposed method
was successfully applied to 20 breast milk samples. BPA, bisphenol
F (BPF), bisphenol S (BPS), and bisphenol AF (BPAF) were detected.
BPA was still the dominant BP, followed by BPF. This is the first
report describing the occurrence of BPF and BPAF in breast milk
UCP2 knockdown enhanced p53 mitochondrial translocation and decreased colony formation in response to TPA treatment.
<p>(A) UCP2 knockdown efficiency examined by Western blot analysis. (B) p53 mitochondrial translocation. (C) Soft agar colony formation assays of JB6 P+ cells (light micrograph: 100× magnification). (D) Quantification of formed colonies. Cells grown in 0.33% soft agar containing 6.66 ng/ml TPA or vehicle (DMSO 1000× diluted). *: Significant difference compared to DMSO treatment. **: Significant difference compared to normal cells with TPA treatment.</p
Enzymatic activity of PKM2 was measured from cells treated with DMSO as the vehicle control, taxol (8 nM), shikonin (2.5 μM), and the combination.
<p>*, p<0.05 compared to the control group. The experiments have been repeated more than three times.</p
Apoptosis analysis of the combination treatment.
<p>Both caspase activity (A) and annexin V conjugates for apoptosis (B) were measured in MDA-MB-231 cells treated with DMSO as the vehicle control, taxol (8 nM), shikonin (2.5 μM), and the combination. Activity was measured as Δabsorbance after 1 hr incubation with the DTT assay buffer and the AFC-conjugated substrate (n = 3 in each group). <i>* P</i><0.05 when compared to the control (DMSO), # <i>P</i><0.05 when compared to the Taxol; ** <i>P</i><0.05 when compared between SKN and Taxol+SKN.</p
Enzymatic activity and expression levels of PKM2 were detected in both human breast cancer MDA-MB-231 (MB231) cells and MCF-7 cells.
<p>Whole cell lysate was subjected to activity and Western blot analysis to determine the enzymatic activity (A) and protein expression (B) of PKM2. β-Actin served as the loading control. * <i>P</i><0.05 compared with MCF-7 cells.</p
Mitochondrial uncoupling prevented mitochondrial dysfunction and apoptosis associated with p53 mitochondrial translocation in JB6 P+ cells.
<p>(A) ROS levels. (B) Mitochondrial complex I activities. (C) Mitochondrial membrane potential. (D) Cytochrome <i>c</i> detected in both mitochondrial and cytosolic fractions. GAPDH or SDHB served as the loading control. (E) Cell death levels revealed by the DNA fragmentation ELISA assay. (F) Apoptosis revealed by detection of cleave caspase 3 and caspase 3 activity assay. *: Significant difference compared to the control. **: Significant difference compared to TPA treatment.</p
Hierarchically Structured Porous Nitrogen-Doped Carbon for Highly Selective CO<sub>2</sub> Capture
Nitrogen-doping has proven to be
an effective strategy for enhancing
the CO<sub>2</sub> adsorption capacity of carbon-based adsorbents.
However, it remains challenging to achieve a high doping level of
nitrogen (N) and a significant porosity in a carbon material simultaneously.
Here we report a facile method that enables the fabrication of ordered
macroporous nitrogen-doped carbon with the content of N as high as
31.06 wt %. Specifically, we used polyÂ(EGDMA-<i>co</i>-MAA)
microspheres as a template to fabricate the structure which can strongly
interact with melamine (the precursor of nitrogen-doped carbon framework),
self-assemble into three-dimensionally ordered structure, and be easily
removed afterward. Upon chemical activation, significant microporosity
is generated in this material without degrading its ordered macroporous
structure, giving rise to a hierarchically structured porous nitrogen-doped
carbon in which a remarkable N content (14.45 wt %) is retained. This
material exhibits a moderate CO<sub>2</sub> adsorption capacity (2.69
mmol g<sup>–1</sup> at 25 °C and 3.82 mmol g<sup>–1</sup> at 0 °C under 1 bar) and an extraordinarily high CO<sub>2</sub>/N<sub>2</sub> selectivity (134), which is determined from the single-component
adsorption isotherms based on the ideal adsorption solution theory
(IAST) method. This value far exceeds the CO<sub>2</sub>/N<sub>2</sub> selectivity of thus-far reported carbon-based adsorbents including
various nitrogen-doped ones. We believe that such an unprecedented
CO<sub>2</sub>/N<sub>2</sub> selectivity is largely associated with
the unusually high N content as well as the partially graphitic framework
of this material