98 research outputs found
Phase Behavior and Rheological Properties of Salt-Free Catanionic TTAOH/DA/H<sub>2</sub>O System in the Presence of Hydrophilic and Hydrophobic Salts
In the cationic and anionic (catanionic) surfactant mixed system, tetradecyltrimethylammonium hydroxide (TTAOH)/decanoic acid (DA)/H2O, abundant phase behaviors were obtained in the presence of hydrophilic and hydrophobic salts. The microstructures of typical Lα phases with the different compositions were characterized by the transmission electron microscope (TEM) images. Aqueous double-phase transition induced by addition of hydrophilic salts was observed when the cationic surfactant was in excess. Salt-induced reversible vesicle phases could be obtained when the anionic surfactant was excess, whereas the vesicle phase at lower salinity behaves highly viscoelastic but is much less viscoelastic with high salinity which was demonstrated by measuring their rheological properties. The Lα phase with the positive membrane charges can be finally transferred into an L1 phase with added salts. The ion specificity of hydrophilic and hydrophobic salts is discussed, and the order of cations is summarized, which is significant for the further study of the Hofmeister effects on catanionic surfactant mixed systems
Exploration of Sulfur-Containing Nanoparticles: Synthesis, Microstructure Analysis, and Sensing Potential
In
this work, three different sulfur sources such as sulfur powder,
sodium sulfide, and sodium thiosulfate are selected to prepare sulfur-derived
quantum dots (S-QDs), Na2S-derived nanoparticles (NS-NPs),
and Na2S2O3–-derived
QDs (NSO-QDs) in the presence of NaOH or assisted by hydrogen peroxide
etching. The low sulfur percentage in the above three samples and
the synthesis experiments in the presence of nitrogen/oxygen all support
that poly(ethylene glycol) (PEG) plays an important role during the
assembly process and the definition of sulfur dots is not accurate.
For photophysical features, remarkable green quantum dots (S-QDs)
possess an excitation-independent emission peak at 500 nm. But NS-NPs
and NSO-QDs demonstrate observable shift tendency, and the evolution
of emission profiles varies from 480 to 586 nm. NSO-QDs can be used
as a fluorescent probe for highly selective and quantitative detection
of Ni2+ in an aqueous solution in the presence of potential
interfering ions with a low detection limit (0.18 μM) and a
wide linear range (8–380 μM). Their reusability performance
has also been demonstrated by employing dimethylglyoxime as the restoration
reagent
Enzyme Kinetics in Liquid Crystalline Mesophases: Size Matters, But Also Topology
Lyotropic liquid crystalline systems
(LLCs) are excellent immobilizing
carriers for enzymes, due to their biocompatibility and well-defined
pore nanostructure. Here we show that the liquid crystalline mesophase
topology can greatly influence the enzymatic activity in a typical
peroxidase (Horseradish peroxidase, HRP) enzymatic reaction. Enzyme
kinetics was investigated in different LLC mesophases based on monolinolein,
with varying symmetries and dimensions such as the 1D cylindrical
inverse hexagonal phase (H<sub>II</sub>), the 2D planar lamellar phase
(L<sub>α</sub>), and two 3D bicontinuous cubic phases of double
diamond (Pn3m) and gyroid (Ia3d) space groups. As expected, the mesophase
with largest water channel size shows highest activity, regardless
of the topology. Interestingly, however, when mesophases with different
topologies have the same water channel size, then the topology plays
the dominant role, and the enzyme showed the highest activity in the
3D tetra-fold connected Pn3m, followed by the Ia3d with trifold connectivity,
and finally the 1D H<sub>II</sub> phase. This study demonstrates that
the enzymatic activity in LLC mesophases depends on both the water
channel size and the topology of the mesophase
Ab Initio Reaction Path Analysis for the Initial Hydrogen Abstraction from Organic Acids by Hydroxyl Radicals
Hydrogen abstraction from organic acids by hydroxyl radicals is the initial rate- and selectivity-determining step in the photochemical oxidation of organic acids in the troposphere. To quantify the rate and selectivity of these reactions, the abstraction of hydrogen atoms at the acid, α, β, γ, and methyl positions was studied for valeric acid, C4H9COOH, using first principles calculations. At the high-pressure limit, an overall rate coefficient at 298 K of 4.3 × 106 m3/(mol s) was calculated. The dominant pathways are abstraction at the β; the γ; and, to a lesser extent, the acid positions; with a selectivity of 55, 28, and 8%, respectively. This differs from the high selectivity for the acid channel for formic and acetic acids and from the thermodynamic preference for abstraction at the α position, but it is consistent with the experimentally observed preference for the β and the γ positions in larger organic acids. The rate and selectivity are controlled by the strength of hydrogen bonds between the acid group and the hydroxyl radical in the different transition states and do not correlate with the stability of the products. Natural bond orbital analysis was used to quantify the nature and strength of the hydrogen bonds. At 298 K and below 0.1 atm, the collision frequency is insufficient to stabilize the prereactive complexes, and the reaction becomes chemically activated. However, the reaction rate and the selectivity are largely unaffected by this mechanistic change
Table_1_Comparison of physiological uptake of normal tissues in patients with cancer using 18F-FAPI-04 and 18F-FAPI-42 PET/CT.xlsx
PurposeTo calculate the physiological uptake of various tissues in patients with cancer using 18F-AlF-NOTA-FAPI-04 (18F-FAPI-04) and 18F-AlF-NOTA-FAPI-42 (18F-FAPI-42) PET/CT and to compare the variation in standard uptake values between the two scans.Materials and methodsThis retrospective analysis included 40 patients with cancer who underwent 18F-FAPI; the first 20 patients received 18F-FAPI-04 PET/CT and the remaining 20 patients received 18F-FAPI-42 PET/CT. A total of 49 normal tissues, including the brain (cerebrum/cerebellum), parotid and submandibular glands, palatine tonsils, and thyroid, were identified on CT images. For these normal tissues, maximum standardized uptake value (SUVmax) and mean standardized uptake value (SUVmean) were calculated. We also compared the SUVmean of identical tissues to explore the difference in biodistribution between the two radiotracers.ResultsThe accumulation of 18F-FAPI-04 and 18F-FAPI-42 showed an analogous pattern. High uptake of both radiotracers in the gallbladder, uterus, submandibular gland, and renal pelvis was demonstrated (range: SUVmax, 4.01–5.75; SUVmean, 2.92–4.22). Furthermore, the uptake of bony tissues was slightly higher in 18F-FAPI-42 than in 18F-FAPI-04 (range: SUVmean, 0.4 ± 0.22–0.9 ± 0.34 and 0.3 ± 0.24–0.7 ± 0.18, respectively, p 18F-FAPI-04 than in 18F-FAPI-42 (range: SUVmean, 0.9 ± 0.24–1.5 ± 0.35 and 0.9 ± 0.26–1.2 ± 0.37, respectively, p ConclusionsBoth radioligands exhibited similar physiological uptake of normal tissues in patients with cancers. In addition, 18F-FAPI-42 demonstrated higher uptake of bone tissues than 18F-FAPI-04 while showing lower uptake of soft tissues than 18F-FAPI-04.</p
Image_1_Comparison of physiological uptake of normal tissues in patients with cancer using 18F-FAPI-04 and 18F-FAPI-42 PET/CT.tif
PurposeTo calculate the physiological uptake of various tissues in patients with cancer using 18F-AlF-NOTA-FAPI-04 (18F-FAPI-04) and 18F-AlF-NOTA-FAPI-42 (18F-FAPI-42) PET/CT and to compare the variation in standard uptake values between the two scans.Materials and methodsThis retrospective analysis included 40 patients with cancer who underwent 18F-FAPI; the first 20 patients received 18F-FAPI-04 PET/CT and the remaining 20 patients received 18F-FAPI-42 PET/CT. A total of 49 normal tissues, including the brain (cerebrum/cerebellum), parotid and submandibular glands, palatine tonsils, and thyroid, were identified on CT images. For these normal tissues, maximum standardized uptake value (SUVmax) and mean standardized uptake value (SUVmean) were calculated. We also compared the SUVmean of identical tissues to explore the difference in biodistribution between the two radiotracers.ResultsThe accumulation of 18F-FAPI-04 and 18F-FAPI-42 showed an analogous pattern. High uptake of both radiotracers in the gallbladder, uterus, submandibular gland, and renal pelvis was demonstrated (range: SUVmax, 4.01–5.75; SUVmean, 2.92–4.22). Furthermore, the uptake of bony tissues was slightly higher in 18F-FAPI-42 than in 18F-FAPI-04 (range: SUVmean, 0.4 ± 0.22–0.9 ± 0.34 and 0.3 ± 0.24–0.7 ± 0.18, respectively, p 18F-FAPI-04 than in 18F-FAPI-42 (range: SUVmean, 0.9 ± 0.24–1.5 ± 0.35 and 0.9 ± 0.26–1.2 ± 0.37, respectively, p ConclusionsBoth radioligands exhibited similar physiological uptake of normal tissues in patients with cancers. In addition, 18F-FAPI-42 demonstrated higher uptake of bone tissues than 18F-FAPI-04 while showing lower uptake of soft tissues than 18F-FAPI-04.</p
Data_Sheet_1_Melatonin Treatment for Sleep Disorders in Parkinson's Disease: A Meta-Analysis and Systematic Review.docx
ObjectiveThe efficacy of melatonin on sleep disorders in Parkinson's disease (PD) is still unclear. The purpose of this study was to investigate the efficacy of melatonin on sleep disorders in PD by summarizing evidence from randomized clinical trials (RCTs).MethodsPubMed, Cochrane Library, EMBASE, and Web of Science databases were searched for studies published before 20 August 2021. Results were analyzed using Review Manager 5.2 software. We used Trial Sequential Analysis (TSA) software to avoid false-positive results caused by random errors.ResultsWe included 7 studies in this systematic review and meta-analysis. The results of the meta-analysis showed that compared with placebo, the subjective sleep quality of patients with PD significantly improved after melatonin treatment (MD = −2.19, 95% CI: −3.53 to −0.86, P = 0.001). In the systematic review, we qualitatively analyzed the efficacy of melatonin on the objective sleep quality of patients with PD, and the results showed that melatonin exerted a positive effect with good safety and tolerability. However, there was no significant improvement in excessive daytime sleepiness assessed by the Epworth Sleepiness Scale (ESS).ConclusionWe found that melatonin can significantly improve the subjective and objective sleep quality of patients with PD with good safety and tolerability. Melatonin could be considered an effective treatment for insomnia in patients with PD.</p
Table1_Carbon Emission Peak Paths Under Different Scenarios Based on the LEAP Model—A Case Study of Suzhou, China.DOCX
Environmental pollution caused by energy consumption is a global problem. Optimization of the energy system will contribute to the sustainable development of city, especially of the industrial cities. Based on the Long-term Energy Alternative Planning System (LEAP) model, the LEAP-Suzhou model was established to explore the energy system optimization and emission reduction path of Suzhou to 2050. By accounting for current energy consumption and carbon emissions, the baseline scenario (BAU) was established. According to the different methods and intensities of energy transformation, an industrial structure optimization scenario (ISO), an energy structure optimization scenario (ESO), and an energy transformation optimization scenario (ETD) were created. Combined with the energy flow diagram, the energy structure and the direction of optimization were analyzed. The results showed that the baseline scenario will consume 259.954 million tons of standard coal by 2050, and the carbon emission will be 677.6 Mt. Compared with BAU, the ISO, ESO, and ETD scenarios will reduce energy consumption by 37.9%, 37.4%, and 74.8%, respectively, by 2050. ETD had the best carbon dioxide reduction, followed by ESO, and finally ISO. Among them, the carbon emission of ETD will reach its peak around 2030 and decrease to 73.8 Mt in 2050, resulting in the best emission reduction effect. This scenario is the best path for Suzhou to achieve the goal of “carbon peak and neutrality” and sustainable development. The LEAP-Suzhou model successfully explores the low carbon path of Suzhou, provides policy guidance for the optimization of energy transition and carbon neutrality of industrial cities, In the future, the energy structure should be further optimized in Suzhou, and advanced energy technologies should be introduced to improve energy efficiency, especially for the power generation sector, and the proportion of clean energy such as gas should be further expanded.</p
Lyotropic Liquid Crystalline Cubic Phases as Versatile Host Matrices for Membrane-Bound Enzymes
Lyotropic
liquid crystalline cubic mesophases can function as host
matrices for enzymes because of their biomimetic structural characteristics,
optical transparency, and capability to coexist with water. This study
demonstrates that the in meso immobilized membrane-bound enzyme d-fructose dehydrogenase (FDH) preserves its full activity,
follows ideal Michaelis–Menten kinetics, and shows improved
stability compared to its behavior in solution. Even after 5 days,
the immobilized FDH retained its full activity in meso, whereas a
model hydrophilic enzyme, horseradish peroxidase, maintained only
21% of its original activity. We reason that the lipidic bilayers
in the three-dimensional structures of cubic mesophases provide an
ideal environment for the reconstitution of a membrane-bound enzyme.
The preserved activity, long-term stability, and reusability demonstrate
that these hybrid nanomaterials are ideal matrices for biosensing
and biocatalytic fuel cell applications
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