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1.
ACS Macro Lett ; 13(4): 415-422, 2024 Apr 16.
Artículo en Inglés | MEDLINE | ID: mdl-38526986

RESUMEN

Linear polyisoprene (PI) and SiO2-g-PI particle brushes were synthesized by both conventional and activators regenerated by electron transfer (ARGET) atom transfer radical polymerization (ATRP). The morphology and solution state study on the particle brushes by transmission electron microscopy (TEM) and dynamic light scattering (DLS) confirmed the successful grafting of PI ligands on the silica surface. The presence of nanoparticle clusters suggests low grafting density (associated with the limited initiation efficiency of ARGET for PI). Nevertheless, particle brushes with very high molecular weights, Mn > 300,000, were prepared, which significantly improved the dispersion of silica nanoparticles and also contributed to excellent mechanical performance. The reinforcing effects of SiO2 nanofillers and very high molecular weight PI ligands were investigated by dynamic mechanical analysis (DMA) as well as computational simulation for the cured linear PI homopolymer/SiO2-g-PI particle brush bulk films.

2.
BMC Pregnancy Childbirth ; 23(1): 863, 2023 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-38102587

RESUMEN

BACKGROUND: To investigate the predictive value of ultrasound indicators in early pregnancy for the outcome of caesarean scar pregnancy (CSP) after pregnancy termination. METHODS: This study retrospectively analysed the ultrasound images of 98 CSP patients who underwent transabdominal ultrasound-guided hysteroscopic curettage during early pregnancy at Changsha Hospital for Maternal and Child Health Care between January 2017 and October 2021. Patients were equally divided into a case group and a control group. The case group included 49 CSP patients with postoperative complications, such as intraoperative blood loss ≥ 200 ml or retained products of conception (RPOC). The remaining 49 CSP patients, with similar age and gestational age and with good postoperative outcomes, such as intraoperative blood loss ≤ 50 ml and no RPOC, were included in the control group. CSP was classified into three types according to the location of the gestational sac (GS) relative to the uterine cavity line (UCL) and serosal contour. Differences in ultrasound indicators between the case and control group were compared. RESULTS: There were significant differences between the case and control groups in the mean gestational sac diameter (MGSD), residual myometrium thickness (RMT) between the GS and the bladder, blood flow around the GS at the site of the previous caesarean incision, and types of CSP (P < 0.05). The rs of each ultrasound indicator were as follows: 0.258, -0.485, 0.369, 0.350. The optimal threshold for predicting good postoperative outcomes, such as intraoperative blood loss ≤ 50 ml and no RPOC, by receiver operating characteristic (ROC) curve analysis of the RMT was 2.3 mm. CONCLUSION: Our findings show that the RMT, blood flow around the GS at the site of the previous caesarean incision, and types of CSP have a low correlation with postoperative complications, such as intraoperative blood loss ≥ 200 ml or RPOC, of early pregnancy termination in patients with CSP. To some extent, this study may be helpful for clinical prognostic prediction of patients with CSP and formulation of treatment strategies. Given the low correlation between these three indicators and postoperative complications, further studies are needed to identify indicators that can better reflect the postoperative outcomes of CSP patients.


Asunto(s)
Aborto Inducido , Complicaciones del Embarazo , Embarazo Ectópico , Embarazo , Femenino , Niño , Humanos , Pérdida de Sangre Quirúrgica , Estudios Retrospectivos , Cicatriz/etiología , Cicatriz/complicaciones , Ultrasonido , Cesárea/efectos adversos , Embarazo Ectópico/diagnóstico por imagen , Embarazo Ectópico/etiología , Embarazo Ectópico/cirugía , Aborto Inducido/efectos adversos , Complicaciones del Embarazo/etiología , Complicaciones Posoperatorias/etiología , Resultado del Tratamiento
3.
ACS Sustain Chem Eng ; 11(8): 3346-3358, 2023 Feb 27.
Artículo en Inglés | MEDLINE | ID: mdl-36874196

RESUMEN

Anticipated increases in the frequency and intensity of extreme temperatures will damage crops. Methods that efficiently deliver stress-regulating agents to crops can mitigate these effects. Here, we describe high aspect ratio polymer bottlebrushes for temperature-controlled agent delivery in plants. The foliar-applied bottlebrush polymers had near complete uptake into the leaf and resided in both the apoplastic regions of the leaf mesophyll and in cells surrounding the vasculature. Elevated temperature enhanced the in vivo release of spermidine (a stress-regulating agent) from the bottlebrushes, promoting tomato plant (Solanum lycopersicum) photosynthesis under heat and light stress. The bottlebrushes continued to provide protection against heat stress for at least 15 days after foliar application, whereas free spermidine did not. About 30% of the ∼80 nm short and ∼300 nm long bottlebrushes entered the phloem and moved to other plant organs, enabling heat-activated release of plant protection agents in phloem. These results indicate the ability of the polymer bottlebrushes to release encapsulated stress relief agents when triggered by heat to provide long-term protection to plants and the potential to manage plant phloem pathogens. Overall, this temperature-responsive delivery platform provides a new tool for protecting plants against climate-induced damage and yield loss.

4.
ACS Macro Lett ; 11(10): 1217-1223, 2022 Oct 18.
Artículo en Inglés | MEDLINE | ID: mdl-36194204

RESUMEN

Poly(methyl methacrylate/n-butyl acrylate) [P(MMA/BA)] copolymer with an alternating structure was synthesized via an activator regenerated by electron transfer (ARGET) atom transfer radical (co)polymerization (ATRP) of 2-ethylfenchyl methacrylate (EFMA) and n-butyl acrylate (BA) with subsequent postpolymerization modifications (PPM). Due to the steric hindrance of the bulky pendant group of EFMA, as well as the low reactivity ratio of BA in copolymerization with methacrylates, copolymerization of EFMA and BA generated a copolymer with a high content of alternating dyads. A subsequent PPM procedure of the alternating EFMA/BA copolymer was comprised of the hydrolysis of a tertiary ester by trifluoroacetic acid and methylation by (trimethylsilyl)diazomethane. After the modifications, the architecture of the obtained alternating MMA/BA copolymers was compared with gradient and statistical copolymers with overall similar compositions, molecular weights, and dispersities. 13C NMR indicated the absence of either MMA/MMA/MMA or BA/BA/BA sequences, in contrast to an abundance of homotriads in either the statistical or especially in the gradient copolymer. All three copolymers had similar glass transition temperatures, as measured by differential scanning calorimetry (DSC), but the alternating copolymer had the narrowest range of glass transition.


Asunto(s)
Diazometano , Metacrilatos , Acrilatos , Ésteres , Metacrilatos/química , Metilmetacrilatos , Polimerizacion , Polímeros , Ácido Trifluoroacético
5.
J Obstet Gynaecol Res ; 48(7): 1683-1690, 2022 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-35384174

RESUMEN

AIM: This study aimed to ascertain whether the lower anterior myometrial thickness (MT) between the bladder and the gestational sac in early pregnancy can be used to predict clinical outcomes in women with cesarean scar pregnancy (CSP) after expectant management. METHODS: We retrospectively analyzed the clinical data and early pregnancy ultrasound images of 21 patients who received expectant management for CSP. Among them, 11 patients with serious complications during pregnancy, such as intraoperative blood loss ≥1000 mL or with severe forms of morbidly adherent placenta (MAP; placenta increta or placenta percreta), were assigned to group A. The remaining 10 patients without serious complications during pregnancy were assigned to group B. The difference in MT between groups A and B was analyzed using nonparametric Mann-Whitney U test. RESULTS: There was a statistically significant difference in MT between the groups (U = 20.000, p = 0.013). The area under the receiver operating characteristics (ROC) curve was 0.818, and the optimal cut-off value for MT was 3.3 mm. CONCLUSION: Lower anterior MT around the gestational sac was correlated with severe complications, such as massive intraoperative bleeding or severe forms of MAP in patients with CSP.


Asunto(s)
Placenta Accreta , Embarazo Ectópico , Cesárea/efectos adversos , Cicatriz/complicaciones , Femenino , Humanos , Placenta Accreta/etiología , Embarazo , Embarazo Ectópico/cirugía , Estudios Retrospectivos , Espera Vigilante
6.
Cell Cycle ; 21(14): 1502-1511, 2022 07.
Artículo en Inglés | MEDLINE | ID: mdl-35446199

RESUMEN

Renal cell carcinoma (RCC) is one of the most frequent human tumors and has brought great threats to the health of the people around the globe. It was reported that linc01133, a long non-coding RNA (lncRNA), was involved in the pathogenesis and development of several human cancer. But the biological role of linc01133 in RCC is still not understood. The present study aimed to investigate the biological functions of linc01133 in RCC. We did some biological experiments in this study, including quantitative real-time polymerase chain reaction (qRT-PCR), western blotting, MTT assay, wound healing assay, Transwell invasion assay and xenograft tumor assay. In this study, we found the expression levels of linc01133 markedly increased in the RCC tissues compared with the normal tissues. And we found that the over-expressing of linc01133 promoted cell proliferation, migration and invasion, the interfering of linc01133 inhibited cell proliferation, migration and invasion. Furthermore, we found that the interfering of linc01133 inhibited tumor growth in murine xenograft models. Additionally, we found that linc01133 promotes RCC cell proliferation, migration and invasion through sponging miR-760. Collectively, our work preliminarily illuminated the tumor-promoting role of linc01133 in RCC and the potential molecular mechanism. Thus, our study may provide some evidence for the treatment of RCC.


Asunto(s)
Carcinoma de Células Renales , Neoplasias Renales , MicroARNs , ARN Largo no Codificante , Animales , Carcinoma de Células Renales/patología , Línea Celular Tumoral , Movimiento Celular/genética , Proliferación Celular/genética , Regulación Neoplásica de la Expresión Génica , Humanos , Neoplasias Renales/patología , Ratones , MicroARNs/genética , MicroARNs/metabolismo , ARN Largo no Codificante/genética , ARN Largo no Codificante/metabolismo
7.
ACS Nano ; 16(3): 4467-4478, 2022 03 22.
Artículo en Inglés | MEDLINE | ID: mdl-35179875

RESUMEN

Plant abiotic stress induces reactive oxygen species (ROS) accumulation in leaves that can decrease photosynthetic performance and crop yield. Materials that scavenge ROS and simultaneously provide nutrients in vivo are needed to manage this stress. Here, we incorporated both ROS scavenging and ROS triggered agent release functionality into an ∼20 nm ROS responsive star polymer (RSP) poly(acrylic acid)-block-poly((2-(methylsulfinyl)ethyl acrylate)-co-(2-(methylthio)ethyl acrylate)) (PAA-b-P(MSEA-co-MTEA)) that alleviated plant stress by simultaneous ROS scavenging and nutrient agent release. Hyperspectral imaging indicates that all of the RSP penetrates through the tomato leaf epidermis, and 32.7% of the applied RSP associates with chloroplasts in mesophyll. RSP scavenged up to 10 µmol mg-1 ROS in vitro and suppressed ROS in vivo in stressed tomato (Solanum lycopersicum) leaves. Reaction of the RSP with H2O2in vitro enhanced the release of nutrient agent (Mg2+) from star polymers. Foliar applied RSP increased photosynthesis in plants under heat and light stress compared to untreated controls, enhancing the carbon assimilation, quantum yield of CO2 assimilation, Rubisco carboxylation rate, and photosystem II quantum yield. Mg loaded RSP improved photosynthesis in Mg deficient plants, mainly by promoting Rubisco activity. These results indicate the potential of ROS scavenging nanocarriers like RSP to alleviate abiotic stress in crop plants, allowing crop plants to be more resilient to heat stress, and potentially other climate change induced abiotic stressors.


Asunto(s)
Polímeros , Solanum lycopersicum , Peróxido de Hidrógeno , Fotosíntesis , Hojas de la Planta , Especies Reactivas de Oxígeno , Ribulosa-Bifosfato Carboxilasa
8.
J Hazard Mater ; 430: 128475, 2022 05 15.
Artículo en Inglés | MEDLINE | ID: mdl-35183827

RESUMEN

Vertical transmission of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) along a vertical column of flats has been documented in several outbreaks of coronavirus disease 2019 (COVID-19) in Guangdong and Hong Kong. We describe an outbreak in Luk Chuen House, involving two vertical columns of flats associated with an unusually connected two-stack drainage system, in which nine individuals from seven households were infected. The index case resided in Flat 812 (8th floor, Unit 12), two flats (813, 817) on its opposite side reported one case each (i.e., a horizontal sub-cluster). All other flats with infected residents were vertically associated, forming a vertical sub-cluster. We injected tracer gas (SF6) into drainage stacks via toilet or balcony of Flat 812, monitored gas concentrations in roof vent, toilet, façade, and living room in four of the seven flats with infected residents and four flats with no infected residents. The measured gas concentration distributions agreed with the observed distribution of affected flats. Aerosols leaking into drainage stacks may generate the vertical sub-cluster, whereas airflow across the corridor probably caused the horizontal sub-cluster. Sequencing and phylogenetic analyses also revealed a common point-source. The findings provided additional evidence of probable roles of drainage systems in SARS-CoV-2 transmission.


Asunto(s)
COVID-19 , Aerosoles , COVID-19/epidemiología , Brotes de Enfermedades , Vivienda , Humanos , Filogenia , SARS-CoV-2
9.
Indoor Air ; 32(1): e12952, 2022 01.
Artículo en Inglés | MEDLINE | ID: mdl-34747064

RESUMEN

This study aims to develop a fast-response sulfur hexafluoride (SF6 ) measuring system, and evaluate its performance in tracer gas measurements for studying transient airborne contaminant transport. The new system is based on a quartz-enhanced photoacoustic spectroscopy (QEPAS) sensor using a quantum cascade laser. Transient SF6 tracer gas measurements were carried out in an environmental chamber with an instantaneous source using both the QEPAS system and a traditional commercial instrument. Real-time SF6 concentrations, peak SF6 concentrations and average SF6 concentrations for one room time constant under two air change rates obtained by the two instruments were compared. The results show that the QEPAS system, which features a 0.4 s data acquisition interval, can provide detailed real-time SF6 concentrations even when the concentration is changing rapidly. The QEPAS system successfully captured the peak SF6 concentrations for all the studies cases, while commercial instrument failed in most studied cases. In most of the cases, the two instruments obtained similar average SF6 concentrations for one room time constant. However, when the concentration was in rapid change, the two systems would report significantly different results. The QEPAS system can be potentially applied in transient tracer gas measurements under complex scenarios.


Asunto(s)
Contaminación del Aire Interior , Cuarzo , Contaminación del Aire Interior/análisis , Análisis Espectral/métodos , Hexafluoruro de Azufre/análisis , Hexafluoruro de Azufre/química
10.
Polym Adv Technol ; 32(10): 3948-3954, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-34924736

RESUMEN

Poly(ether ether ketone) (PEEK) is a semi-crystalline thermoplastic with excellent mechanical and chemical properties. PEEK exhibits a high degree of resistance to thermal, chemical, and bio-degradation. PEEK is used as biomaterial in the field of orthopaedic and dental implants; however, due to its intrinsic hydrophobicity and inert surface, PEEK does not effectively support bone growth. Therefore, new methods to modify PEEK's surface to improve osseointegration are key to next generation polymer implant materials. Unfortunately, PEEK is a challenging material to both modify and subsequently characterize thus stymieing efforts to improve PEEK osseointegration. In this manuscript, we demonstrate how surface-initiated atom transfer radical polymerization (SI-ATRP) can be used to modify novel PEEK microparticles (PMP). The hard core-soft shell microparticles were synthesized and characterized by DLS, ATR-IR, XPS and TEM, indicating the grafted materials increased solubility and stability in a range of solvents. The discovered surface grafted PMP can be used as compatibilizers for the polymer-tissue interface.

11.
Environ Sci Technol ; 55(15): 10758-10768, 2021 08 03.
Artículo en Inglés | MEDLINE | ID: mdl-34283571

RESUMEN

Determination of how the properties of nanocarriers of agrochemicals affect their uptake and translocation in plants would enable more efficient agent delivery. Here, we synthesized star polymer nanocarriers poly(acrylic acid)-block-poly(2-(methylsulfinyl)ethyl acrylate) (PAA-b-PMSEA) and poly(acrylic acid)-block-poly((2-(methylsulfinyl)ethyl acrylate)-co-(2-(methylthio)ethyl acrylate)) (PAA-b-P(MSEA-co-MTEA)) with well-controlled sizes (from 6 to 35 nm), negative charge content (from 17% to 83% PAA), and hydrophobicity and quantified their leaf uptake, phloem loading, and distribution in tomato (Solanum lycopersicum) plants 3 days after foliar application of 20 µL of a 1g L-1 star polymer solution. In spite of their property differences, ∼30% of the applied star polymers translocated to other plant organs, higher than uptake of conventional foliar applied agrochemicals (<5%). The property differences affected their distribution in the plant. The ∼6 nm star polymers exhibited 3 times higher transport to younger leaves than larger ones, while the ∼35 nm star polymer had over 2 times higher transport to roots than smaller ones, suggesting small star polymers favor symplastic unloading in young leaves, while larger polymers favor apoplastic unloading in roots. For the same sized star polymer, a smaller negative charge content (yielding ζ ∼ -12 mV) enhanced translocation to young leaves and roots, whereas a larger negative charge (ζ < -26 mV) had lower mobility. Hydrophobicity only affected leaf uptake pathways, but not translocation. This study can help design agrochemical nanocarriers for efficient foliar uptake and targeting to desired plant organs, which may decrease agrochemical use and environmental impacts of agriculture.


Asunto(s)
Hojas de la Planta , Polímeros , Transporte Biológico , Interacciones Hidrofóbicas e Hidrofílicas , Raíces de Plantas
12.
Acc Chem Res ; 54(7): 1779-1790, 2021 04 06.
Artículo en Inglés | MEDLINE | ID: mdl-33751886

RESUMEN

Atom-transfer radical polymerization (ATRP) is a well-known technique for the controlled polymerization of vinyl monomers under mild conditions. However, as with any other radical polymerization, ATRP typically requires rigorous oxygen exclusion, making it time-consuming and challenging to use by nonexperts. In this Account, we discuss various approaches to achieving oxygen tolerance in ATRP, presenting the overall progress in the field.Copper-mediated ATRP, which we first discovered in the late 1990s, uses a CuI/L activator that reversibly reacts with the dormant C(sp3)-X polymer chain end, forming a X-CuII/L deactivator and a propagating radical. Oxygen interferes with activation and chain propagation by quenching the radicals and oxidizing the activator. At ATRP equilibrium, the activator is present at a much higher concentration than the propagating radicals. Thus, oxidation of the activator is the dominant inhibition pathway. In conventional ATRP, this reaction is irreversible, so oxygen must be strictly excluded to achieve good results.Over the last two decades, our group has developed several ATRP techniques based on the concept of regenerating the activator. When the oxidized activator is continuously converted back to its active reduced form, then the catalytic system itself can act as an oxygen scavenger. Regeneration can be accomplished by reducing agents and photo-, electro-, and mechanochemical stimuli. This family of methods offers a degree of oxygen tolerance, but most of them can tolerate only a limited amount of oxygen and do not allow polymerization in an open vessel.More recently, we discovered that enzymes can be used in auxiliary catalytic systems that directly deoxygenate the reaction medium and protect the polymerization process. We developed a method that uses glucose oxidase (GOx), glucose, and sodium pyruvate to very effectively scavenge oxygen and enable open-vessel ATRP. By adding a second enzyme, horseradish peroxidase (HPR), we managed to extend the role of the auxiliary enzymatic system to generating carbon-based radicals and changed ATRP from an oxygen-sensitive to an oxygen-fueled reaction.While performing control experiments for the enzymatic methods, we noticed that using sodium pyruvate under UV irradiation triggers polymerization without the presence of GOx. This serendipitous discovery allowed us to develop the first oxygen-proof, small-molecule-based, photoinduced ATRP system. It has oxygen tolerance similar to that of the enzymatic methods, exhibits superior compatibility with both aqueous media and organic solvents, and avoids problems associated with purifying polymers from enzymes. The system was able to rapidly polymerize N-isopropylacrylamide, a challenging monomer, with a high degree of control.These contributions have substantially simplified the use of ATRP, making it more practical and accessible to everyone.


Asunto(s)
Oxígeno/metabolismo , Radicales Libres/química , Radicales Libres/metabolismo , Glucosa/química , Glucosa/metabolismo , Glucosa Oxidasa/química , Glucosa Oxidasa/metabolismo , Peroxidasa de Rábano Silvestre/química , Peroxidasa de Rábano Silvestre/metabolismo , Oxidación-Reducción , Oxígeno/química , Polimerizacion , Ácido Pirúvico/química , Ácido Pirúvico/metabolismo
13.
Exp Mol Pathol ; 117: 104522, 2020 12.
Artículo en Inglés | MEDLINE | ID: mdl-32866521

RESUMEN

OBJECTIVE: This study aimed to investigate whether the protection of miR-302a-3p in myocardial ischemia-reperfusion injury (MIRI) is mediated through the suppression of mitophagy. METHODS: We constructed a mouse I/R model in vivo by the ligation of left anterior descending coronary artery for 45 min followed by 2 h reperfusion, and an in vitro model by treating mouse cardiomyocytes with hypoxia-reoxygenation (H/R). Knockdown experiments were then performed in vivo and in vitro to determine the effects of miR-302a-3p knockdown on the mitophagy, mitochondrial dysfunction and oxidative stress and apoptosis. The potential targets of miR-302a-3p were further studied by bioinformatics analysis, luciferase assays, quantitative real-time PCR and western blotting. RESULTS: MiR-302a-3p expression was significantly upregulated in mice subjected to MIRI and in H/R-treated mouse cardiomyocytes. Functional analyses demonstrated that inhibition of miR-302a-3p protected cardiac tissues against I/R-induced apoptosis and mitophagy, mitochondrial damage and mitochondrial oxidative stress. Furthermore, FOXO3 was identified as the direct target of miR-302a-3p. Mechanistically, knockdown of FOXO3 partially reversed the cardioprotective effects of miR-302a-3p inhibitor. CONCLUSION: Our study suggested that inhibition of miR-302a-3p promoted mitochondrial autophagy and inhibited oxidative stress by targeting FOXO3 to suppress myocardial apoptosis, representing a potential target for MIRI treatment.


Asunto(s)
Proteína Forkhead Box O3/genética , MicroARNs/genética , Isquemia Miocárdica/genética , Daño por Reperfusión/genética , Animales , Apoptosis/genética , Vasos Coronarios/patología , Vasos Coronarios/cirugía , Modelos Animales de Enfermedad , Regulación de la Expresión Génica/genética , Técnicas de Silenciamiento del Gen , Humanos , Ligadura , Ratones , Mitofagia/genética , Isquemia Miocárdica/patología , Miocitos Cardíacos/metabolismo , Miocitos Cardíacos/patología , Estrés Oxidativo/genética , Daño por Reperfusión/patología
14.
Macromol Rapid Commun ; 41(1): e1900424, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31631429

RESUMEN

Small molecule biomimetics inspired by the active site of the [FeFe]-hydrogenase enzymes have shown promising electrocatalytic activity for hydrogen (H2 ) generation. However, most of the active-site mimics based on [2Fe-2S] clusters are not water-soluble which limits the use of these electrocatalysts to organic media. Polymer-supported [2Fe-2S] systems, in particular, single-site metallopolymer catalysts, have shown drastic improvements for electrocatalytic H2 generation in aqueous milieu. [2Fe-2S] complexes functionalized within well-defined macromolecular supports via covalent bonding have demonstrated water solubility, enhanced site-isolation, and improved chemical stability during catalysis. In this report, the synthesis of a new propanedithiolate (pdt)-[2Fe-2S] complex bearing a single α-bromoester moiety for use in atom transfer radical polymerization (ATRP) is demonstrated as a novel metalloinitiator to prepare water-soluble poly(2-dimethylaminoethyl methacrylate) grafted (PDMAEMA-g-[2Fe-2S]) metallopolymers. Using this approach, metallopolymers with controllable molecular weights (Mn = 5-40 kg mol-1 ) and low dispersity (D, Mw /Mn = 1.09-1.36) are prepared, which allows for the first time observation of the effect of the metallopolymers' chain length on the electrocatalytic activity. The ability to control the composition and molecular weight of these metallopolymers enables macromolecular engineering via ATRP of these materials to determine optimal structural features of metallopolymer catalysts for H2 production.


Asunto(s)
Hidrógeno/metabolismo , Hierro/química , Polímeros/química , Azufre/química , Catálisis , Dominio Catalítico , Complejos de Coordinación/química , Técnicas Electroquímicas , Hidrógeno/química , Hidrogenasas/química , Conformación Molecular , Peso Molecular , Polimerizacion , Polímeros/síntesis química
15.
Molecules ; 24(21)2019 Nov 02.
Artículo en Inglés | MEDLINE | ID: mdl-31684005

RESUMEN

Copper is the most common metal catalyst used in atom transfer radical polymerization (ATRP), but iron is an excellent alternative due to its natural abundance and low toxicity compared to copper. In this work, two new iron-porphyrin-based catalysts inspired by naturally occurring proteins, such as horseradish peroxidase, hemoglobin, and cytochrome P450, were synthesized and tested for ATRP. Natural protein structures were mimicked by attaching imidazole or thioether groups to the porphyrin, leading to increased rates of polymerization, as well as providing polymers with low dispersity, even in the presence of ppm amounts of catalysts.


Asunto(s)
Biomimética , Hierro/química , Polimerizacion , Porfirinas/química , Catálisis , Cobre/química , Sistema Enzimático del Citocromo P-450/química , Hemoglobinas/química , Peroxidasa de Rábano Silvestre/química , Imidazoles/química , Estructura Molecular , Oxidación-Reducción , Polímeros/química , Sulfuros/química
16.
ACS Appl Mater Interfaces ; 11(42): 38531-38536, 2019 Oct 23.
Artículo en Inglés | MEDLINE | ID: mdl-31599570

RESUMEN

Titanium (Ti) and its alloys are used in orthopedic and dental implants due to their excellent physical properties and biocompatibility. Although Ti exhibits superior osteoconductive properties compared to those of polymer-based implants, improved bone-on growth properties are required for enhanced surgical outcomes and improved recovery surgical interventions. Herein, we demonstrate a novel surface modification strategy to enhance the osteoconductivity of Ti surfaces through the grafting-from procedure of a reactive copolymer via surface-initiated atom transfer radical polymerization (SI-ATRP). Then, postpolymerization conjugation of the P15 peptide, an osteoblast binding motif, was successfully carried out. Subsequent in vitro studies revealed that the surface modification promoted osteoblast attachment on the Ti discs at 6 and 24 h. Moreover, mineral matrix deposition by osteoblasts was greater for the surface-modified Ti than for plain Ti and P15 randomly absorbed onto the Ti surface. These results suggest that the strategy for postpolymerization incorporation of P15 onto a Ti surface with a polymer interface may provide improved osseointegration outcomes, leading to enhanced quality of life for patients.


Asunto(s)
Aleaciones/farmacología , Colágeno/química , Oseointegración/efectos de los fármacos , Fragmentos de Péptidos/química , Titanio/química , Aleaciones/química , Animales , Supervivencia Celular/efectos de los fármacos , Implantes Dentales , Ratones , Osteoblastos/citología , Osteoblastos/metabolismo
17.
Macromol Rapid Commun ; 40(10): e1800877, 2019 May.
Artículo en Inglés | MEDLINE | ID: mdl-30650236

RESUMEN

Good control of tacticity, molecular weight, and architecture is attained via atom transfer radical polymerization (ATRP) of N-hydroxyethyl acrylamide (HEAA), in a one-pot process in the presence of Y(OTf)3 . The effect of temperature, ratio of [Y(OTf)3 ]/[HEAA], and ATRP procedure on the tacticity and degree of control over the polymerization is investigated in detail. Under optimal conditions, using photo ATRP and 15% Y(OTf)3, the content of meso dyads (m) can be increased from 42% to 80% in a homopolymer with a dispersity D = 1.22. Well-defined stereoblock copolymers, atactic- b -isotactic poly(HEAA), with D = 1.27, are obtained by adding Y(OTf)3 at a specific conversion, initially started without Y(OTf)3 .


Asunto(s)
Acrilamidas/síntesis química , Ácidos de Lewis/química , Polimerizacion , Polímeros/síntesis química , Acrilamidas/química , Ácidos de Lewis/síntesis química , Peso Molecular , Polímeros/química , Temperatura
18.
ACS Macro Lett ; 8(5): 603-609, 2019 May 21.
Artículo en Inglés | MEDLINE | ID: mdl-35619358

RESUMEN

An aqueous electrochemically mediated atom transfer radical polymerization (eATRP) was performed in a small volume solution (75 µL) deposited on a screen-printed electrode (SPE). The reaction was open to air, thanks to the use of glucose oxidase (GOx) as an oxygen scavenger. Well-defined poly(2-(methylsulfinyl)ethyl acrylate) (PMSEA), poly(oligo(ethylene oxide) methyl ether methacrylate) (POEOMA), and corresponding DNA-polymer biohybrids were synthesized by the small-volume eATRP at room temperature. The reactions were simplified and polymerization rates increased by the application of the enzyme deoxygenating system and the compact electrochemical setup. Importantly, the volume of polymerization mixture was lowered to microliters, which not only decreases the cost for each reaction, but can also be potentially implemented in combinatorial chemistry and electrode-array configurations for high-throughput systems.

19.
Angew Chem Int Ed Engl ; 57(49): 16157-16161, 2018 12 03.
Artículo en Inglés | MEDLINE | ID: mdl-30329207

RESUMEN

Atom transfer radical polymerization (ATRP) can be carried out in a flask completely open to air using a biocatalytic system composed of glucose oxidase (GOx) and horseradish peroxidase (HRP) with an active copper catalyst complex. Nanomolar concentrations of the enzymes and ppm amounts of Cu provided excellent control over the polymerization of oligo(ethylene oxide) methyl ether methacrylate (OEOMA500 ), generating polymers with high molecular weight (Mn >70 000) and low dispersities (1.13≤D≤1.27) in less than an hour. The continuous oxygen supply was necessary for the generation of radicals and polymer chain growth as demonstrated by temporal control and by inducing hypoxic conditions. In addition, the enzymatic cascade polymerization triggered by oxygen was used for a protein and DNA functionalized with initiators to form protein-b-POEOMA and DNA-b-POEOMA bioconjugates, respectively.

20.
Biosci Rep ; 38(4)2018 08 31.
Artículo en Inglés | MEDLINE | ID: mdl-30042171

RESUMEN

More and more studies have shown that long non-coding RNAs (lncRNAs) play critical roles in various biological processes of bladder cancer, including proliferation, apoptosis, migration and cell cycle arrest. LncRNA long intergenic noncoding RNA 00511 (linc00511) is one of the lncRNAs highly expressed in bladder cancer tissues and cells. However, little is known about the roles and mechanisms of linc00511 in bladder cancer. Here, we demonstrated that linc00511 was highly expressed in bladder cancer tissues and cells. Linc00511 knockdown could cause the cell proliferation suppression and cell cycle arrest, which were mediated by p18, p21, CDK4, cyclin D1 and phosphorylation Rb. Suppressed linc00511 could induce the apoptosis in T24 and BIU87 cells via activating the caspase pathway. Down-regulation of linc00511 could also suppress the migration and invasion of T24 and BIU87 cells. In addition, we found that the expression of linc00511 was negatively correlated with that of miR-15a-3p in the clinical bladder cancer samples. Further mechanistic studies showed that linc00511 knockdown induced proliferation inhibition, and apoptosis increase might be regulated through suppressing the activities of Wnt/ß-catenin signaling pathway. Thus, we revealed that knockdown of linc00511 suppressed the proliferation and promoted apoptosis of bladder cancer cells through suppressing the activities of Wnt/ß-catenin signaling pathway. Moreover, we suggested that linc00511 could be a potential therapeutic target and novel biomarker in bladder cancer.


Asunto(s)
Apoptosis , Proliferación Celular , Regulación Neoplásica de la Expresión Génica , Técnicas de Silenciamiento del Gen , ARN Largo no Codificante/genética , Neoplasias de la Vejiga Urinaria/genética , Vía de Señalización Wnt , Animales , Puntos de Control del Ciclo Celular , Movimiento Celular , Regulación hacia Abajo , Terapia Genética , Humanos , Masculino , Ratones Endogámicos BALB C , Neoplasias de la Vejiga Urinaria/metabolismo , Neoplasias de la Vejiga Urinaria/patología , Neoplasias de la Vejiga Urinaria/terapia
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