4 research outputs found
Fluorescent Protein-Based Turn-On Probe through a General Protection–Deprotection Design Strategy
We demonstrated a
general protection–deprotection strategy
for the design of fluorescent protein biosensors through the construction
of a turn-on Hg<sup>2+</sup> sensor. A combination of fluorescent
protein engineering and unnatural amino acid mutagenesis was used.
Unlike previously reported fluorescent protein-based Hg<sup>2+</sup> sensors that relied on the binding of Hg<sup>2+</sup> to the sulfhydryl
group of cysteine residues, a well-established chemical reaction,
oxymercuration, was transformed into biological format and incorporated
into our sensor design. This novel Hg<sup>2+</sup> sensor displayed
good sensitivity and selectivity both in vitro and in live bacterial
cells. Over 60-fold change in fluorescence signal output was observed
in the presence of 10 ÎĽM Hg<sup>2+</sup>, while such a change
was undetectable when nine other metal ions were tested. This new
design strategy could expand the repertoire of fluorescent protein-based
biosensors for the detection of small-molecule analytes
Improved Photoinduced Fluorogenic Alkene–Tetrazole Reaction for Protein Labeling
The
1,3-dipolar cycloaddition reaction between an alkene and a
tetrazole represents one elegant and rare example of fluorophore-forming
bioorthogonal chemistry. This is an attractive reaction for imaging
applications in live cells that requires less intensive washing steps
and/or needs spatiotemporal resolutions. In the present work, as an
effort to improve the fluorogenic property of the alkene–tetrazole
reaction, an aromatic alkene (styrene) was investigated as the dipolarophile.
Over 30-fold improvement in quantum yield of the reaction product
was achieved in aqueous solution. According to our mechanistic studies,
the observed improvement is likely due to an insufficient protonation
of the styrene–tetrazole reaction product. This finding provides
useful guidance to the future design of alkene–tetrazole reactions
for biological studies. Fluorogenic protein labeling using the styrene–tetrazole
reaction was demonstrated both in vitro and in vivo. This was realized
by the genetic incorporation of an unnatural amino acid containing
the styrene moiety. It is anticipated that the combination of styrene
with different tetrazole derivatives can generally improve and broaden
the application of alkene–tetrazole chemistry in real-time
imaging in live cells
DataSheet_1_Association of overweight, obesity and risk of urinary incontinence in middle-aged and older women: a meta epidemiology study.docx
AimsThe aim of this meta-analysis is to evaluate the potential correlation between obesity and overweight, and the vulnerability to urinary incontinence (UI) in women aged middle-aged and above.MethodsWe searched PubMed, Cochrane Library, and Embase for observational studies published between the inception of the databases and April 25, 2023. A fixed-effects model was used when the P>0.1 and the I2 ≤ 50%. In cases where I2 ≥ 50% (indicating significant heterogeneity), a random-effects model was applied. For the purpose of evaluating publication bias, a funnel plot and Egger’s test were used. Stata 14.0 was used for all statistical analyses.FindingsThis meta-analysis includes 16 observational studies, covering29,618 individuals. The pooled analysis shows that being overweight(25 kg/m2≤BMI2) in middle-aged and elderly women is more likely to develop UI (OR=1.27; 95% CI: 1.17-1.37; I2 = 51.8%, P=0.013). Middle-aged and elderly women with obesity(30 kg/m2≤BMI2) are significantly more likely to develop UI (OR=1.60; 95% CI: 1.42-1.81; I2 = 71.8%, P=0.000). In addition, the results indicated a higher probability of UI in middle-aged and older women with obesity class II (BMI≥35 kg/m2) (OR=1.85; 95% CI: 1.59-2.16; I2 = 48.1%, P=0.103). In subgroup analysis, there is no direct relationship between the obesity in middle-aged and elderly women and an increased risk of stress urinary incontinence (SUI) (OR=1.31; 95% CI: 0.99-1.74; I2 = 63.7%, P=0.011). In middle-aged and elderly women with obesity are more likely to develop urgent urinary incontinence (UUI) (OR=2.11; 95% CI: 1.54-2.89; I2 = 80.2%, P=0.000).ConclusionIn this meta-analysis, overweight and obesity are associated with an increased risk of UI in middle-aged and elderly women. Obesity and overweight are independent risk factors for UI, as demonstrated by this study.Systematic Review Registrationhttps://www.crd.york.ac.uk/PROSPERO/, identifier CRD42023421986.</p
Dye-Sensitized Solar Cells Employing a Multifunctionalized Hierarchical SnO<sub>2</sub> Nanoflower Structure Passivated by TiO<sub>2</sub> Nanogranulum
We investigated a facile multifunctionalized
hierarchical SnO<sub>2</sub> nanoflower photoelectrode passivated
by a layer of TiO<sub>2</sub> nanogranulum. The hierarchical SnO<sub>2</sub> nanoflower
with thin nanorod and nanosheet has a unique morphology that can afford
excellent electron transport propertiesî—¸orientation overall,
which results in a significant diminution in the charge diffusion
route and a rapid collection in FTO substrate. The passivated photoanode
not only improved the distribution of dyes in the photoelectrode and
reduced the surface defects of SnO<sub>2</sub> photoelectrode to accommodate
more dyes, but also suppressed the charge recombination and prolonged
electron lifetime by introducing a barrier layer. The microstructure
of the sample was investigated by X-ray diffraction (XRD), scanning
electron microscopy (SEM) and transmission electron microscopy (TEM).
The surface areas (<i>S</i><sub>BET</sub>) and pore size
distribution were detected on BET measurement. The amounts of dye
were calculated from UV–vis. The interfacial charge transfer
process and the charge recombination were characterized by EIS and
IMPS/IMVS measurements. The DSSCs assembled with multifunctionalized
photoanode exhibits favorable energy conversion efficiency. The photocurrent
increased from 5.44 to 12.74 mA cm<sup>2</sup>, the photovoltage from
440 to 760 mV, and the fill factor from 43.58% to 57.58%. As a result,
the cell’s conversion efficiency increased by a factor of 5.3
from 1.05% to 5.60%. The increase in efficiency originates from higher
open-circuit potential and higher short-circuit current as well as
from superior light scattering effect, long electron lifetime, and
slower electron recombination