Low-Molecular-Weight, High-Mechanical-Strength, and Solution-Processable Telechelic Poly(ether imide) End-Capped with Ureidopyrimidinone

Solution-processable poly­(ether imide)­s (PEIs) with ureido­pyrimidinone (UPy) end groups were prepared by incorporating mono­isocyanato-6-methyl­isocytosine into amine-terminated PEI oligomers. After functionalization with UPy end groups, PEI with a molecular weight as low as 8 kDa (8k-PEI-UPy) can be solution-cast to form films. Tensile tests revealed that 8k-PEI-UPy had an outstanding Young’s modulus higher than those of state-of-the-art high-molecular-weight commercial PEIs. The tensile strength, maximum elongation, and Young’s modulus of 8k-PEI-UPy were 87.2 ± 10.8 MPa, 3.10 ± 0.39%, and (3.20 ± 0.14) × 10³ MPa, respectively. The discovery herein significantly advances the chemistry of high-temperature PEI resins. UPy-based supramolecular chemistry is an effective and general strategy to achieve outstanding mechanical properties for PEI oligomers

In Situ Construction of a Coordination Zirconocene Tetrahedron

The current study describes the first in situ synthesis and characterization of a new family of cationic coordination tetrahedra of both the V₄F₄ and V₄E₆ type, which are constructed by a new building block based on a trinuclear zirconocene moiety and the dicarboxylate or tricarboxylate anions

In Situ Construction of a Coordination Zirconocene Tetrahedron

The current study describes the first in situ synthesis and characterization of a new family of cationic coordination tetrahedra of both the V₄F₄ and V₄E₆ type, which are constructed by a new building block based on a trinuclear zirconocene moiety and the dicarboxylate or tricarboxylate anions

In Situ Construction of a Coordination Zirconocene Tetrahedron

The current study describes the first in situ synthesis and characterization of a new family of cationic coordination tetrahedra of both the V₄F₄ and V₄E₆ type, which are constructed by a new building block based on a trinuclear zirconocene moiety and the dicarboxylate or tricarboxylate anions

Using Scanning-Probe Block Copolymer Lithography and Electron Microscopy To Track Shape Evolution in Multimetallic Nanoclusters

Here we describe a general method for synthesizing multimetallic core–shell nanoclusters on surfaces. By patterning seeds at predesignated locations using scanning-probe block copolymer lithography, we can track shape evolution in nanoclusters and elucidate their growth pathways using electron microscopy. The growth of core–shell nanostructures on surface-bound seeds is a highly anisotropic process and often results in multimetallic anisotropic nanostructures. The shell grows at specific edge and corner sites of the patterned seeds and propagates predominately from the top hemisphere of the seeds

Two-Dimensional Plasmonic Nanoparticle as a Nanoscale Sensor to Probe Polymer Brush Formation

Conventional analysis and characterization of polymer brush formation relies on laborious methods that use a quartz crystal microbalance, atomic force microscope, microcantilever, or other tools that measure the concentration change of solutions. Herein we develop a simple and easy method that utilizes intrinsically flat two-dimensional (2D) plasmonic nanoparticles as sensors for unveiling the mechanism of polymer brush formation on surfaces. Via ultraviolet–visible spectroscopy, the plasmonic nanoparticles can be used to determine the amount of polymers near the surface <i>in situ</i>. As the amount of polymers increases near the surface, the nanoparticle characteristic localized surface plasmon resonance wavelength redshifts, and the shift amount corresponds linearly to the polymer density near the surface. By functionalizing the nanoparticles in solutions of thiolated polyethylene glycol (PEG-SH) with or without PEG disulfide (PEG-S-S-PEG), the three-regime kinetics of the polymer brush formation is confirmed. The fast adsorption and slow chain rearrangement in the first regime are found to be the causes of the latent regime. In the latent regime, the adsorbed polymer chains rearrange to anchor their ends onto the surface and contract to liberate space so that other polymer chains can graft onto the surface until saturation. The fundamental understanding gained herein enables the design of surfaces with complex chemistries and properties, which can find broad applications in responsive sensors, films, and coatings. Moreover, the novel analytical method of using 2D plasmonic nanoparticle as a sensor to understand the polymer brush formation is applicable to investigating the grafting of other molecules such as self-assembled monolayers, protein, and DNA

Image_4_Extreme temperature exposure and urolithiasis: A time series analysis in Ganzhou, China.jpeg

BackgroundAmbient temperature change is a risk factor for urolithiasis that cannot be ignored. The association between temperature and urolithiasis varies from region to region. Our study aimed to analyze the impact of extremely high and low temperatures on the number of inpatients for urolithiasis and their lag effect in Ganzhou City, China.MethodsWe collected the daily number of inpatients with urolithiasis in Ganzhou from 2018 to 2019 and the meteorological data for the same period. The exposure-response relationship between the daily mean temperature and the number of inpatients with urolithiasis was studied by the distributed lag non-linear model (DLNM). The effect of extreme temperatures was also analyzed. A stratification analysis was performed for different gender and age groups.ResultsThere were 38,184 hospitalizations for urolithiasis from 2018 to 2019 in Ganzhou. The exposure-response curve between the daily mean temperature and the number of inpatients with urolithiasis in Ganzhou was non-linear and had an observed lag effect. The warm effects (30.4°C) were presented at lag 2 and lag 5–lag 9 days, and the cold effects (2.9°C) were presented at lag 8 and lag 3–lag 4 days. The maximum cumulative warm effects were at lag 0–10 days (cumulative relative risk, CRR = 2.379, 95% CI: 1.771, 3.196), and the maximum cumulative cold effects were at lag 0–5 (CRR = 1.182, 95% CI: 1.054, 1.326). Men and people between the ages of 21 and 40 were more susceptible to the extreme temperatures that cause urolithiasis.ConclusionExtreme temperature was correlated with a high risk of urolithiasis hospitalizations, and the warm effects had a longer duration than the cold effects. Preventing urolithiasis and protecting vulnerable people is critical in extreme temperature environments.</p

Image_1_Extreme temperature exposure and urolithiasis: A time series analysis in Ganzhou, China.JPEG

BackgroundAmbient temperature change is a risk factor for urolithiasis that cannot be ignored. The association between temperature and urolithiasis varies from region to region. Our study aimed to analyze the impact of extremely high and low temperatures on the number of inpatients for urolithiasis and their lag effect in Ganzhou City, China.MethodsWe collected the daily number of inpatients with urolithiasis in Ganzhou from 2018 to 2019 and the meteorological data for the same period. The exposure-response relationship between the daily mean temperature and the number of inpatients with urolithiasis was studied by the distributed lag non-linear model (DLNM). The effect of extreme temperatures was also analyzed. A stratification analysis was performed for different gender and age groups.ResultsThere were 38,184 hospitalizations for urolithiasis from 2018 to 2019 in Ganzhou. The exposure-response curve between the daily mean temperature and the number of inpatients with urolithiasis in Ganzhou was non-linear and had an observed lag effect. The warm effects (30.4°C) were presented at lag 2 and lag 5–lag 9 days, and the cold effects (2.9°C) were presented at lag 8 and lag 3–lag 4 days. The maximum cumulative warm effects were at lag 0–10 days (cumulative relative risk, CRR = 2.379, 95% CI: 1.771, 3.196), and the maximum cumulative cold effects were at lag 0–5 (CRR = 1.182, 95% CI: 1.054, 1.326). Men and people between the ages of 21 and 40 were more susceptible to the extreme temperatures that cause urolithiasis.ConclusionExtreme temperature was correlated with a high risk of urolithiasis hospitalizations, and the warm effects had a longer duration than the cold effects. Preventing urolithiasis and protecting vulnerable people is critical in extreme temperature environments.</p

Image_3_Extreme temperature exposure and urolithiasis: A time series analysis in Ganzhou, China.JPEG

BackgroundAmbient temperature change is a risk factor for urolithiasis that cannot be ignored. The association between temperature and urolithiasis varies from region to region. Our study aimed to analyze the impact of extremely high and low temperatures on the number of inpatients for urolithiasis and their lag effect in Ganzhou City, China.MethodsWe collected the daily number of inpatients with urolithiasis in Ganzhou from 2018 to 2019 and the meteorological data for the same period. The exposure-response relationship between the daily mean temperature and the number of inpatients with urolithiasis was studied by the distributed lag non-linear model (DLNM). The effect of extreme temperatures was also analyzed. A stratification analysis was performed for different gender and age groups.ResultsThere were 38,184 hospitalizations for urolithiasis from 2018 to 2019 in Ganzhou. The exposure-response curve between the daily mean temperature and the number of inpatients with urolithiasis in Ganzhou was non-linear and had an observed lag effect. The warm effects (30.4°C) were presented at lag 2 and lag 5–lag 9 days, and the cold effects (2.9°C) were presented at lag 8 and lag 3–lag 4 days. The maximum cumulative warm effects were at lag 0–10 days (cumulative relative risk, CRR = 2.379, 95% CI: 1.771, 3.196), and the maximum cumulative cold effects were at lag 0–5 (CRR = 1.182, 95% CI: 1.054, 1.326). Men and people between the ages of 21 and 40 were more susceptible to the extreme temperatures that cause urolithiasis.ConclusionExtreme temperature was correlated with a high risk of urolithiasis hospitalizations, and the warm effects had a longer duration than the cold effects. Preventing urolithiasis and protecting vulnerable people is critical in extreme temperature environments.</p

Image_2_Extreme temperature exposure and urolithiasis: A time series analysis in Ganzhou, China.jpeg

BackgroundAmbient temperature change is a risk factor for urolithiasis that cannot be ignored. The association between temperature and urolithiasis varies from region to region. Our study aimed to analyze the impact of extremely high and low temperatures on the number of inpatients for urolithiasis and their lag effect in Ganzhou City, China.MethodsWe collected the daily number of inpatients with urolithiasis in Ganzhou from 2018 to 2019 and the meteorological data for the same period. The exposure-response relationship between the daily mean temperature and the number of inpatients with urolithiasis was studied by the distributed lag non-linear model (DLNM). The effect of extreme temperatures was also analyzed. A stratification analysis was performed for different gender and age groups.ResultsThere were 38,184 hospitalizations for urolithiasis from 2018 to 2019 in Ganzhou. The exposure-response curve between the daily mean temperature and the number of inpatients with urolithiasis in Ganzhou was non-linear and had an observed lag effect. The warm effects (30.4°C) were presented at lag 2 and lag 5–lag 9 days, and the cold effects (2.9°C) were presented at lag 8 and lag 3–lag 4 days. The maximum cumulative warm effects were at lag 0–10 days (cumulative relative risk, CRR = 2.379, 95% CI: 1.771, 3.196), and the maximum cumulative cold effects were at lag 0–5 (CRR = 1.182, 95% CI: 1.054, 1.326). Men and people between the ages of 21 and 40 were more susceptible to the extreme temperatures that cause urolithiasis.ConclusionExtreme temperature was correlated with a high risk of urolithiasis hospitalizations, and the warm effects had a longer duration than the cold effects. Preventing urolithiasis and protecting vulnerable people is critical in extreme temperature environments.</p