Photo-crosslinking polymerization stands as a fundamental pillar in the domains of chemistry, biology, and medicine. Yet, prevailing strategies heavily rely on ultraviolet/visible (UV/Vis) light to ...elicit in situ crosslinking. The inherent perils associated with UV radiation, namely the potential for DNA damage, coupled with the limited depth of tissue penetration exhibited by UV/Vis light, severely restrict the scope of photo-crosslinking within living organisms. Although near-infrared light has been explored as an external excitation source, enabling partial mitigation of these constraints, its penetration depth remains insufficient, particularly within bone tissues. In this study, we introduce an approach employing X-ray activation for deep-tissue hydrogel formation, surpassing all previous boundaries. Our approach harnesses a low-dose X-ray-activated persistent luminescent phosphor, triggering on demand in situ photo-crosslinking reactions and enabling the formation of hydrogels in male rats. A breakthrough of our method lies in its capability to penetrate deep even within thick bovine bone, demonstrating unmatched potential for bone penetration. By extending the reach of hydrogel formation within such formidable depths, our study represents an advancement in the field. This application of X-ray-activated polymerization enables precise and safe deep-tissue photo-crosslinking hydrogel formation, with profound implications for a multitude of disciplines.
Sulfur-containing polymer supported palladium nanoparticles (Pd/SPMB) were prepared by using the cross-linked poly(N,N′-methylene bis(acrylamide)) (SPMB) as the platform. The SPMB was synthesized ...via the reversible addition–fragmentation chain transfer (RAFT) polymerization, from which the sulfur inherently exists in the RAFT polymer due to the use of thiocarbonate as the chain transfer agent, and could be further utilized as a modifier of Pd nanoparticles. The Pd/SPMB showed size-dependent activity and selectivity in the semihydrogenation of alkynes to alkenes. The catalyst with an average Pd size of 5.3 nm was active in the semihydrogenation of both internal and terminal alkynes. Most of the surface of Pd NPs was covered (or poisoned) by sulfide and thiolate due to the moderate complexation strength between Pd NPs and SPMB, thus leading to the selectivity enhancement toward alkene. Furthermore, the catalyst was highly stable and can be reused 10 times without an appreciable loss in either activity or selectivity.
With the aim of determining the damage characteristics and a reasonable positional arrangement of the surrounding rock in a bottom-pumping roadway influenced by mining in a high-gas mine, the ...boundary equation for the plastic zone of the surrounding rock in a circular roadway under an unequal compressive stress field was adopted to analyze the relationship between the distribution characteristics of the plastic zone of the bottom-pumping roadway and the stability of the rock surrounding the bottom-pumping roadway under different bidirectional stress ratios. This was carried out in the bottom-pumping roadway of the working face of Licun coal mine 3301 as the engineering background, where the nature of the coal seams mined is bituminous coal, and the absolute gas outflow is 0.5 m3/min−1. A numerical simulation was used to analyze the distribution characteristics of the surrounding rock stress and the bidirectional stress ratio, as well as the deformation and damage characteristics of the surrounding rock at different positions in the bottom-pumping roadway. A numerical simulation was applied to analyze the distribution characteristics of the surrounding rock stress and the two-way stress ratio, as well as the deformation and damage characteristics of the rock surrounding the bottom-pumping roadway when the bottom-pumping roadway was arranged in different locations. The results show that, with an increase in the bidirectional stress ratio, the plastic zone of the perimeter rock in the bottom-pumping roadway shows nonuniform “butterfly” distribution characteristics, which seriously affects the stability of the rock on the perimeter of the roadway; the stress on the bottom plate of the working face after excavation can be divided into four areas according to the size of the bidirectional stress ratio and the stress loading and unloading states. In addition, the size of the perimeter rock deformation can be sorted into four areas according to the damage range of the perimeter of the rock plastic zone in the bottom-pumping roadway. The size of the deformation in the surrounding rock can be sorted as follows: unpressurized high-stress ratio > unpressurized stress ratio stable area > pressurized low-stress ratio area > original rock stress ratio area. Accordingly, we found that the reasonable location of the bottom-pumping roadway is arranged at the 15 m position outside the hollow area below the coal pillar, along the limestone upper medium-grained sandstone layer along the bottom. The study’s results were applied to the field. The industrial experiments on the site show that the deformation of the surrounding rock is reasonable when the bottom-pumping roadway is dug along the limestone roof and arranged 15 m outside the fault of the mining hollow area below the coal pillar.
The
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F nuclear magnetic resonance (NMR) has been widely employed as a detection tool in biological studies due to its low biological background, noninvasiveness, high sensitivity, and real-time ...monitoring capability. Herein, we report a one-pot synthesis of halloysite nanotubes (HNTs) treated with benzeneboronic acids (6FBB) to afford the HNT-based
19
F NMR probe which is capable to detect the H
2
O
2
in low concentration. The product was well characterized by nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). The intensity of signals of
19
F was enhanced with the increasing concentration of fluorine, and the signals apparently shifted from − 62.68 to − 62.85 ppm upon the addition of H
2
O
2
. The obtained
19
F NMR probes also displayed a long spin-spin (T2) relaxation time (91.27 ms), which can strengthen image intensity. Moreover, the
19
F NMR probe exhibited non-toxic against HeLa cell. The
19
F NMR probe may serve as a desirable candidate to predict the change of H
2
O
2
in vivo.
In this study, a self-condensing vinyl copolymerization/redox (SCVP/Redox) system was constructed to prepare hyperbranched poly(methyl-6-O-methacryloyl-α-D-glucoside) by using Cu(III) as the ...initiator in aqueous solution, in which the –OH group in C-2, C-3 and C-4 position on pyranose rings could be initiated by Cu(III). The branched and linear units were clearly distinguished by nuclear magnetic resonance (1H NMR) to estimate the degree of branching (DB). When the ratio of Cu(III) to monomer fixed at 0.5:1, the DB value reached 0.32, which was higher than the product initiated by Ce(IV). Moreover, the inhibition activity of the products on amyloid fibrillation was investigated by using the hen egg-white lysozyme (HEWL) as a model based on the difference of the initiation sites. The results showed that the –OH groups in C-4 position might play an important role in this process.
Curcumin is a potential natural anticancer drug with low oral bioavailability because of poor water solubility. The aqueous solubility of curcumin is enhanced by means of modification with the ...carbohydrate units. Polymerization of the curcumin-containing monomer with carbohydrate-containing monomer gives the water-soluble glycopolymer bearing curcumin pendant residues. The obtained copolymers (P1 and P2) having desirable water solubility were well-characterized by infrared spectroscopy (IR), nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), UV-Vis absorption spectroscopy, and photoluminescence spectroscopy. The copolymer P2 with a molar ratio of 1:6 (curcumin/carbohydrate) calculated from the proton NMR results exhibits a similar anticancer activity compared to original curcumin, which may serve as a potential chemotherapeutic agent in the field of anticancer medicine.
A series of novel hyperbranched poly2-(α-d-mannopyranosyloxy) ethyl methacrylate-
-
,
'-methylenebisacrylamide (HPManEMA-
-MBA) are synthesized via a reversible addition fragmentation polymerization ...(RAFT). The dosage ratios of linear and branch units are tuned to obtain different degree of branching (DB) in hyperbranched glycopolymers. The DB values are calculated according to the content of nitrogen, which are facilely determined by elemental analysis. The lectin-binding properties of HPManEMA-
-MBA to concanavalin A (ConA) are examined using a turbidimetric assay. The influence of defined DB value and molecular weight of HPManEMA-
-MBA on the clustering rate is studied. Notably, HPManEMA-
-MBAs display a low cytotoxicity in the MTT assay, thus are potential candidates for biomedical applications.
Novel water‐soluble dendronized fluorescent polyfluorenes (DFPFs) are prepared from hydrophilic monomers and hydrophobic comonomers. Incomplete energy transfer is found to result in a two‐color ...emission of the DFPFs at around 410 and 650 nm. The incomplete energy transfer can be attributed to the poor compatibility between the fluorene and benzothiadiazole units. Polyethylene oxide (PEO) encapsulation of the DFPFs shows over 90% cell viability, indicating good biocompatibility. These DFPFs show differential cellular uptake. P1 with fewer PEO chains exhibits limited cellular membrane uptake and low brightness in cells. By contrast, P3 with more PEO chains is efficiently internalized by cells and accumulated in the cytoplasm. A strong fluorescence from whole cells is also observed.
New water‐soluble dendronized fluorescent polyfluorenes are designed. These polyfluorenes show two‐color emission, good cytocompatibility, and differential cellular uptake. P1 shows limited cellular uptake and low brightness in cells. By contrast, P3 is efficiently internalized by cells and accumulated in the cytoplasm. A strong fluorescence from whole cells is also observed.
Hyperbranched poly(methylene-bis-acrylamide), poly(bis(
,
-propyl acryl amide)) (HPNPAM) and poly(bis(
,
-butyl acryl amide)) were synthesized by reversible addition-fragmentation chain transfer ...polymerization. HPNPAMs showed lower critical solution temperature (LCST) due to an appropriate ratio between hydrophilic and hydrophobic groups. The effects of reaction conditions on polymerization were investigated in detail. The structure of HPNPAM was characterized by ¹H NMR, FT-IR, Muti detector-size exclusion chromatography (MDSEC) and Ultravioletvisble (UV-Vis). The α value reached 0.20 and DB was 90%, indicating HPNPAMs with compact topology structure were successfully prepared. LCSTs were tuned by
and the pH value of the solution. The change of molecular size was assayed by dynamic light scattering and scanning electron microscope. These results indicated that the stable uniform nanomicelles were destroyed and macromolecules aggregated together, forming large particles as temperature exceeded LCST. In addition, after the cells were incubated for 24 h, the cell viability reached 80%, which confirmed this new dual responsive HPNPAM had low cytotoxicity.
This paper presents a new robust sliding mode control （SMC） method with well-developed theoretical proof for general uncertain time-varying delay stochastic systems with structural uncertainties and ...the Brownian noise （Wiener process）. The key features of the proposed method are to apply singular value decomposition （SVD） to all structural uncertainties and to introduce adjustable parameters for control design along with the SMC method. It leads to a less-conservative condition for robust stability and a new robust controller for the general uncertain stochastic systems via linear matrix inequality （LMI） forms. The system states are able to reach the SMC switching surface as guaranteed in probability 1. Furthermore, it is theoretically proved that the proposed method with the SVD and adjustable parameters is less conservatism than the method without the SVD. The paper is mainly to provide all strict theoretical proofs for the method and results.
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