o-Nitrobenzyl-based polymer materials with light-regulated multi-functions

o-Nitrobenzyl (oNB)-based polymers have been used as photodegradable materials/surfaces, and responsive biomaterials. While previous studies have mainly focused on the photodegradation of the material by intercalating oNB derivatives in the polymer chains, this thesis pays attention to the utilization of oNB photolysis to tailor the properties of materials, including interface functions, network topology, and bulk properties. To this end, two kinds of oNB based molecules with multifunctional units were designed and synthesized: 2-bromo-N-(2-nitro-3, 4-dihydroxyphenethyl)-2-methylpropanamide (NO2-BDAM, nitrodapomine based initiator) and 2-((2-bromo-2-methylpropanoyl)oxy)ethyl 4-(4-(1-(acryloyloxy)ethyl)-2-methoxy-5-nitrophenoxy) butanoate (vinyl-oNB-Br, photolabile inimer). In part 1, NO2-BDAM, in combination with Mn2(CO)10 as a visible light-sensitive additive, was used to control the growth and detachment of polymer brushes independently. In part 2, vinyl-oNB-Br was introduced into a double network material for in situ regulating topology from connected double network (c-DN) to disconnected double network (d-DN) by light exposure. In the last part, vinyl-oNB-Br was used to graft and detach polymer brushes from a network, leading to the change of network topology and material toughness. These results contribute to the topic of functionalized oNB based polymer systems and tunable topological polymer networks, providing useful strategies both in chemistry and materials.o-Nitrobenzyl (oNB)-basierte Polymere wurden als photoabbaubare Materialien/Oberflächen und responsive Biomaterialien verwendet. Während sich frühere Studien hauptsächlich auf den Photoabbau des Materials durch die Interkalation von oNB-Derivaten in den Polymerketten konzentrierten, widmet sich diese Arbeit der Nutzung der oNB-Photolyse, um die Eigenschaften von Materialien, einschließlich Grenzflächenfunktionen, Netzwerktopologie und Volumeneigenschaften, anzupassen. Zu diesem Zweck wurden zwei Arten von oNB-basierten Molekülen mit multifunktionellen Einheiten entworfen und synthetisiert: 2-Brom-N-(2-nitro-3,4-dihydroxyphenethyl)-2-methylpropanamid (NO2-BDAM, Nitrodapomin-basierter Initiator) und 2 -((2-Brom-2-methylpropanoyl)oxy)ethyl 4-(4-(1-(Acryloyloxy)ethyl)-2-methoxy-5-nitrophenoxy)butanoat (vinyl-oNB-Br, photolabiles Inimer). In Teil 1 wurde NO2-BDAM in Kombination mit Mn2(CO)10 als Additiv für sichtbares Licht verwendet, um das Wachstum und die Ablösung von Polymerbürsten unabhängig voneinander zu kontrollieren. In Teil 2 wurde vinyl-oNB-Br in ein Doppelnetzwerkmaterial eingebracht, um die Topologie in situ vom verbundenen Doppelnetzwerk (c-DN) zum getrennten Doppelnetzwerk (d-DN) durch Lichteinwirkung zu regulieren. Im letzten Teil wurde Vinyl-oNB-Br zum Aufpfropfen und Ablösen von Polymerbürsten aus einem Netzwerk verwendet, was zu einer Änderung der Netzwerktopologie und Materialzähigkeit führte. Diese Ergebnisse tragen zum Thema funktionalisierte oNB-basierte Polymersysteme und abstimmbare topologische Polymernetzwerke bei und liefern nützliche Strategien sowohl in der Chemie als auch in den Materialien

Photoinduced Strain‐Assisted Synthesis of a Stiff‐Stilbene Polymer by Ring‐Opening Metathesis Polymerization

Developing a novel strategy to synthesize photoresponsive polymers is of significance owing to their potential applications. We report a photoinduced strain‐assisted synthesis of main‐chain stiff‐stilbene polymers by using ring‐opening metathesis polymerization (ROMP), activating a macrocyclic π‐bond connected to a stiff‐stilbene photoswitch through a linker. Since the linker acts as an external constraint, the photoisomerization to the E‐form leads to the stiff‐stilbene being strained and thus reactive to ROMP. The photoisomerization of Z‐form to E‐form was investigated using time‐dependent NMR studies and UV/Vis spectroscopy. The DFT calculation showed that the E‐form was less stable due to a lack of planarity. By the internal strain developed due to the linker constraint through photoisomerization, the E‐form underwent ROMP by a second generation Grubbs catalyst. In contrast, Z‐form did not undergo polymerization under similar conditions. The MALDI‐TOF spectrum of E‐form after polymerization showed the presence of oligomers of >5.2 kDa

Poly (lactic-co-glycolic acid)-encapsulated iodine-131 nanoparticles fabricated with rhTSH induce apoptosis and immobilization of thyroid cancer cells

BackgroundAggressive thyroid carcinoma (ATC) usually loses radioiodine avidity to iodine-131 (131I) due to the downregulation of sodium/iodide symporter (NIS). The expression of thyroid stimulating hormone receptor (TSHR) is more persistent than NIS and the administration of recombinant human thyroid stimulating hormone (rhTSH) promotes de novo NIS synthesis. Hence, exploring methods integrating 131I with rhTSH might be a feasible therapeutic strategy for selective delivery of 131I into thyroid cancer to fortify the effect of radioiodine ablation.MethodsThe 131I, poly (lactic-co-glycolic acid) (PLGA) and rhTSH were used to synthesize of the 131I-PLGA-rhTSH nanoparticles. The characteristics of the 131I-PLGA-rhTSH nanoparticles was determined using a light microscopy, scanning electron microscopy (SEM), autoradiography and immunofluorescence (IF) staining. The diameter of the 131I-PLGA-rhTSH nanoparticles was measured with a Mastersizer 3000, and the encapsulation efficiency (EF) of 131I in 131I-PLGA-rhTSH nanoparticles and the radioactivity of a single nanoparticle were determined. Then, the mouse tumor xenograft model was established, and the biodistribution and effect of 131I-PLGA-rhTSH nanoparticles on apoptosis of thyroid cance cells were investigated in vivo. Thereafter, the role of 131I-PLGA-rhTSH nanoparticles in cell viability using cell counting kit-8 and lactate dehydrogenase (LDH) release assays. Subsequently, the underlying mechanism of 131I-PLGA-rhTSH nanoparticles in reducing cell viability was assessed using immunostaining, boyden invasion assays and phalloidin staining.ResultsOur results showed that the method of developing nanoparticles-encapsulated 131I using poly (lactic-co-glycolic acid) (PLGA) and modified with rhTSH (131I-PLGA-rhTSH), was a feasible avenue for the integration of 131I and rhTSH. Meanwhile, the encapsulation efficiency (EF) of 131I-PLGA-rhTSH nanoparticles was approximately 60%, and the radioactivity of a single nanoparticle was about 1.1×10-2 Bq. Meanwhile, the 131I-PLGA-rhTSH nanoparticles were selectively delivered into, gradually enriched and slowly downregulated in xenograft tumor after the administration of 131I-PLGA-rhTSH nanoparticles through tail vein in mouse tumor xenograft model. Thereafter, the tumor weight was significantly reduced after the administration of 131I-PLGA-rhTSH nanoparticles. Subsequently, the application of 131I-PLGA-rhTSH nanoparticles facilitated apoptosis and attenuated immobilization via inhibiting F-actin assembling of FTC-133 cells.ConclusionThe present study develops a suitable approach integrating 131I and rhTSH, and this strategy is a feasible regimen enhancing the effect of radioiodine ablation for the treatment of thyroid cancer

New evidence that vitamin D prevents headache: a bidirectional two-sample Mendelian randomization analysis

BackgroundPrevious observational clinical studies and meta-analyses have yielded inconsistent results regarding the relationship between vitamin D and headache, and the causal relationship remains unclear. The aim of this study was to investigate the causal relationship between vitamin D and headache by bidirectional two-sample Mendelian randomisation (MR) analysis.MethodsThe relationship between high levels of vitamin D and headache was investigated by two-sample MR analysis using publicly available genome-wide association study (GWAS) data. The primary method was inverse variance weighting (IVW), and secondary methods were weighted median and MR-Egger methods. No heterogeneity or horizontal multidirectionality was found in the MR results. The robustness and validity of the findings were assessed using the leave-behind method.ResultsA significant causal relationship was found between high vitamin D levels and headache using the IVW method (OR = 0.848; p = 0.007; 95% CI = 0.752–0.956). However, in a reverse analysis, no evidence of a causal relationship between headache and high levels of vitamin D was found using the IVW method (OR = 1.001; p = 0.906; 95% CI = 0.994–1.006). Our MR analyses showed no significant horizontal multidimensionality or heterogeneity (p > 0.05). Sensitivity analyses confirmed that MR estimates were not affected by single nucleotide polymorphisms (SNPs). Confirmation that our results are robust and valid has been obtained by the leave-one-out method.ConclusionOur study suggests that high levels of vitamin D prevent the risk of headache. However, there is no evidence of a causal relationship between headache and high levels of vitamin D. Vitamin D may reduce the risk of headache

Trace elements in two marine fish cultured in fish cages in Fujian province, China

Two cultured marine fish, the Japanese seabass (Lateolabrax japonicus) and red seabream (Pagrus major) were collected from eight fish cage sites along the coast of Fujian province in China. The concentrations of Ag, As, Cd, Co, Cu, Fe, Mn, Se, and Zn in their muscle, stomach and liver tissue were quantified. The risk of these trace elements to humans through fish consumption was then assessed. The highest concentrations of As, Cd, Se and Zn in fish feed from fish cages were found in Dongshan Station. Moreover, the As levels in the muscles of both species at all sites were generally higher than China's national standard (>1.0 mu g/g). Trace element concentrations in two marine fish followed the order of livers > stomachs > muscles. Although the As levels in two marine caged fish exceeded the permissible standards, the estimated daily intake of As did not exceed the reference dose guideline established by US EPA. For other trace elements examined in this study, their concentrations did not exceed the permissible concentrations of the international standards. (C) 2010 Elsevier Ltd. All rights reserved.China Scholarship Council and Thailand's International Development Cooperation Agency ; Changjiang Scholar Progra

Uptake, absorption efficiency and elimination of DDT in marine phytoplankton, copepods and fish

Uptake, absorption efficiency and elimination of DDT were measured in marine phytoplankton, copepods (Acartia erythraea) and fish (mangrove snappers Lutanus argentimaeulatus). The uptake rate constant of DDT from water decreased with increasing trophic level. The dietary absorption efficiency (AE) of DDT was 10-29\% in copepods and 72-99\% in fish. Food concentration did not significantly affect the AEs of DDT, but the AEs varied considerably among the different food diets. The elimination rate constants of DDT by the copepods were comparable following uptake from the diet and from the water. Elimination of DDT from the fish was exceedingly low. Both aqueous and dietary uptake are equally important for DDT accumulation in the copepods. In fish, dissolved exposure is a more significant route than intake from the diet. The predicted trophic transfer factors in the copepods and the fish are consistent with the field measurements in marine zooplankton and fish. (c) 2005 Elsevier Ltd. All rights reserved

Intelligent storage and washing integrated cabinet based on sine mechanism

This smart storage and washing integrated cabinet based on sine mechanism mainly includes three functional modules: cleaning, storage and transportation. Each part of the organization to cooperate with each other to achieve three basic functions, such as no dead-end dishwashing, tableware storage and according to the instructions to take dishes. Not only that, it also enables additional functions such as drying disinfection and residue filtration. Now that intelligence is rapidly spreading, people’s hands in tableware management are free , Let people only participate in the beginning and end of the tableware management chain, and provide greater convenience to people’s lives

Investigation of Selective Laser Melting of 2205 steel precipitates and heat treatment improvement

2205 Duplex Stainless Steel (DSS) is extensively utilized in various structural components due to its exceptional strength and corrosion resistance. However, for complex structural parts that are challenging to process using conventional methods, Selective Laser Melting (SLM) technology offers a viable solution by enabling layer-by-layer solidification. The rapid cooling rates during the forming process effectively suppress the precipitation of detrimental brittle phases like σ, while concurrently promoting a high proportion of ferrite phases within the structure upon cooling to room temperature. This paper investigates the microstructure and properties of 2205 DSS fabricated via SLM. A notable observation was the presence of abundant precipitates along the ferrite grain boundaries. Characterization through Energy-Dispersive X-ray Spectroscopy (EDS) and Transmission Electron Microscopy (TEM) confirmed the presence of χ-phase and nanoscale closely packed hexagonal Cr2N-phase precipitates. The high fault density and precipitates induced by the SLM process significantly enhanced the sample's strength, resulting in a remarkable tensile strength of 1301.69 ± 19.6 MPa and yield strength of 781.2 ± 12.2 MPa. Subsequent cooling via solid solution water treatment at 1050°C yielded a biphase structure with an austenite content of 54.7% and ferrite content of 45 %. The tensile strength decreased to 815.61 ± 16.4 MPa, and the yield strength decreased to 443.245 ± 7.5 MPa, while the elongation increased significantly from 19.03 ± 1.2% to 46.53 ± 0.7%. These findings demonstrate that the material achieved performance levels comparable to forging and hot rolling processes

Phototriggered Growth and Detachment of Polymer Brushes with Wavelength Selectivity

Both phototriggered growth and removal of polymer chains from surfaces are efficient ways to finely tune interface properties. Combining these two capabilities in one system with independent control can significantly increase the feasibility of photoregulation on surface modification but has not been reported yet. Herein we describe a novel approach to control both the growth and the detachment of polymer brushes independently by light with different wavelengths. The approach is based on a nitrodopamine-based initiator (NO₂–BDAM) which contains a catechol structure for surface modification, alkyl bromide group for radical polymerization, and <i>o</i>-nitrophenyl ethyl moiety for photolysis. When dimanganese decacarbonyl (Mn₂(CO)₁₀) was applied together with NO₂–BDAM as an initiating system, visible light (460 nm) can be used to trigger the site-specific growth of polymer brushes. Resulting polymer brushes can be selectively removed by UV light (360 nm). This method is suitable for different monomers on various substrates, suggesting a facile and robust method to regulate surface properties