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1.
Insect Sci ; 2024 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-38594229

RESUMO

Honeybees and bumblebees play a crucial role as essential pollinators. The special gut microbiome of social bees is a key factor in determining the overall fitness and health of the host. Although bees harbor relatively simple microbial communities at the genus level, recent studies have unveiled significant genetic divergence and variations in gene content within each bacterial genus. However, a comprehensive and refined genomics-based taxonomic database specific to social bee gut microbiomes remains lacking. Here, we first provided an overview of the current knowledge on the distribution and function of social bee gut bacteria, as well as the factors that influence the gut population dynamics. We then consolidated all available genomes of the gut bacteria of social bees and refined the species-level taxonomy, by constructing a maximum-likelihood core genome phylogeny and calculating genome-wide pairwise average nucleotide identity. On the basis of the refined species taxonomy, we constructed a curated genomic reference database, named the bee gut microbe genome sequence database (BGM-GDb). To evaluate the species-profiling performance of the curated BGM-GDb, we retrieved a series of bee gut metagenomic data and inferred the species-level composition using metagenomic intra-species diversity analysis system (MIDAS), and then compared the results with those obtained from a prebuilt MIDAS database. We found that compared with the default database, the BGM-GDb excelled in aligned read counts and bacterial richness. Overall, this high-resolution and precise genomic reference database will facilitate research in understanding the gut community structure of social bees.

2.
Int J Biol Macromol ; 263(Pt 2): 130511, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38423443

RESUMO

The mechanical properties of ionic conductive hydrogels (ICHs) are generally inadequate, leading to their susceptibility to breakage under external forces and consequently resulting in the failure of flexible electronic devices. In this work, a simple and convenient strategy was proposed based on the synergistic effect of ion cross-linking and salting out, in which the hydrogels consisting of polyvinyl alcohol (PVA) and xanthan gum (XG) were immersed in zinc sulfate (ZnSO4) solution to obtain ICHs with exceptional mechanical properties. The salt-out effects between PVA chains and SO42- ions along with the cross-linked network of XG chains and Zn2+ ions contribute to the desirable mechanical properties of ICHs. Notably, the mechanical properties of ICHs can be adjusted by changing the concentration of ZnSO4 solution. Consequently, the optimum fracture stress and the fracture energy can reach 3.38 MPa and 12.13 KJ m-2, respectively. Moreover, the ICHs demonstrated a favorable sensitivity (up to 2.05) when utilized as a strain sensor, exhibiting an accurate detection of human body movements across various amplitudes.


Assuntos
Hidrogéis , Polissacarídeos Bacterianos , Álcool de Polivinil , Humanos , Etanol , Cloreto de Sódio , Condutividade Elétrica , Íons , Poli A , Cloreto de Polivinila
3.
Urology ; 184: 40-44, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38056507

RESUMO

OBJECTIVE: To evaluate the feasibility and safety of a simple noncystoscopic method previously applied in children for removing double-J stents applied in women by comparing the hospitalization time, operation time, costs, complications, and success rate. METHODS: One hundred eighty women who underwent either cystoscopic or noncystoscopic double-J stent removal in a randomized manner. They were randomly assigned 1:1 to groups of cystoscopic double-J stent removal (n = 90) or noncystoscopic double-J stent removal (n = 90). The age ranged from 19 to 72years. After the removal of the double-J stent, the operation time, costs, complications, and success rate were compared between the two groups. RESULTS: The operation time of the noncystoscopic group was lower than that of the cystoscopic group (6.0(5.0,7.0) minutes vs 2.0(2.0,3.0) minutes, P < .001). The hospitalization costs of the noncystoscopic group were significantly shorter than that of the cystoscopic group (1361.2(1331.4,1379.2) Yuan vs 873.9(868.5,896.1) Yuan, P < .001). There were no complications such as infection and massive bleeding in the two groups during and after the operation. Most noncystoscopic double-J stent removal can succeed in less than three attempts (88/90). All patients in the noncystoscopic group used this technique to remove the double-J stent. CONCLUSION: Noncystoscopic removal of double-J stent has the advantages of short operation time and low hospitalization costs. It is a safe and feasible minimally invasive method to replace cystoscopic removal of the double-J stent.


Assuntos
Hospitalização , Stents , Criança , Humanos , Feminino , Adulto Jovem , Adulto , Pessoa de Meia-Idade , Idoso , Estudos de Viabilidade , Duração da Cirurgia
4.
Clin Transl Med ; 13(12): e1505, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38082402

RESUMO

BACKGROUND: Epstein-Barr virus-associated gastric cancer (EBVaGC) is regarded as a distinct molecular subtype of GC, accounting for approximately 9% of all GC cases. Clinically, EBVaGC patients are found to have a significantly lower frequency of lymph node metastasis and better prognosis than uninfected individuals. RNA N6-methyladenosine (m6A) modification has an indispensable role in modulating tumour progression in various cancer types. However, its impact on EBVaGC remains unclear. METHODS: Methylated RNA immunoprecipitation sequencing (MeRIP-seq) and m6A dot blot were conducted to compare the m6A modification levels between EBVaGC and EBV-negative GC (EBVnGC) cells. Western blot, real-time quantitative PCR (RT-qPCR) and immunohistochemistry were applied to explore the underlying mechanism of the reduced m6A modification in EBVaGC. The biological function of fat mass and obesity-associated protein (FTO) was determined in vivo and in vitro. The target genes of FTO were screened by MeRIP-seq, RT-qPCR and Western blot. The m6A binding proteins of target genes were verified by RNA pulldown and RNA immunoprecipitation assays. Chromatin immunoprecipitation and Luciferase report assays were performed to investigate the mechanism how EBV up-regulated FTO expression. RESULTS: M6A demethylase FTO was notably increased in EBVaGC, leading to a reduction in m6A modification, and higher FTO expression was associated with better clinical outcomes. Furthermore, FTO depressed EBVaGC cell metastasis and aggressiveness by reducing the expression of target gene AP-1 transcription factor subunit (FOS). Methylated FOS mRNA was specifically recognized by the m6A 'reader' insulin-like growth factor 2 mRNA binding protein 1/2 (IGF2BP1/2), which enhanced its transcripts stability. Moreover, MYC activated by EBV in EBVaGC elevated FTO expression by binding to a specific region of the FTO promoter. CONCLUSIONS: Mechanistically, our work uncovered a crucial suppressive role of FTO in EBVaGC metastasis and invasiveness via an m6A-FOS-IGF2BP1/2-dependent manner, suggesting a promising biomarker panel for GC metastatic prediction and therapy.


Assuntos
Infecções por Vírus Epstein-Barr , Neoplasias Gástricas , Humanos , Dioxigenase FTO Dependente de alfa-Cetoglutarato/genética , Dioxigenase FTO Dependente de alfa-Cetoglutarato/metabolismo , Infecções por Vírus Epstein-Barr/genética , Infecções por Vírus Epstein-Barr/complicações , Herpesvirus Humano 4/genética , RNA , RNA Mensageiro/genética , Neoplasias Gástricas/patologia , Regulação para Cima/genética
5.
Insects ; 14(10)2023 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-37887806

RESUMO

Antibiotic resistance is a significant and growing threat to global public health. However, antimicrobial peptides (AMPs) have shown promise as they exhibit a broad spectrum of antibacterial activities with low potential for resistance development. Insects, which inhabit a wide range of environments and are incredibly diverse, remain largely unexplored as a source of novel AMPs. To address this, we conducted a screening of the representative transcriptomes from the 1000 Insect Transcriptome Evolution (1KITE) dataset, focusing on the homologous reference genes of Cecropins, the first identified AMPs in insects known for its high efficiency. Our analysis identified 108 Cecropin genes from 105 insect transcriptomes, covering all major hexapod lineages. We validated the gene sequences and synthesized mature peptides for three identified Cecropin genes. Through minimal inhibition concentration and agar diffusion assays, we confirmed that these peptides exhibited antimicrobial activities against Gram-negative bacteria. Similar to the known Cecropin, the three Cecropins adopted an alpha-helical conformation in membrane-like environments, efficiently disrupting bacterial membranes through permeabilization. Importantly, none of the three Cecropins demonstrated cytotoxicity in erythrocyte hemolysis tests, suggesting their safety in real-world applications. Overall, this newly developed methodology provides a high-throughput bioinformatic pipeline for the discovery of AMP, taking advantage of the expanding genomic resources available for diverse organisms.

6.
Proc Natl Acad Sci U S A ; 120(33): e2219634120, 2023 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-37556501

RESUMO

Host specificity is observed in gut symbionts of diverse animal lineages. But how hosts maintain symbionts while rejecting their close relatives remains elusive. We use eusocial bees and their codiversified gut bacteria to understand host regulation driving symbiotic specificity. The cross-inoculation of bumblebee Gilliamella induced higher prostaglandin in the honeybee gut, promoting a pronounced host response through immune deficiency (IMD) and Toll pathways. Gene silencing and vitamin C treatments indicate that reactive oxygen species (ROS), not antimicrobial peptides, acts as the effector in inhibiting the non-native strain. Quantitative PCR and RNAi further reveal a regulatory function of the IMD and Toll pathways, in which Relish and dorsal-1 may regulate Dual Oxidase (Duox) for ROS production. Therefore, the honeybee maintains symbiotic specificity by creating a hostile gut environment to exotic bacteria, through differential regulation of its immune system, reflecting a co-opting of existing machinery evolved to combat pathogens.


Assuntos
Abelhas , Especificidade de Hospedeiro , Síndromes de Imunodeficiência , Receptores Toll-Like , Animais , Bactérias , Abelhas/imunologia , Abelhas/microbiologia , Oxidases Duais , Imunidade , Espécies Reativas de Oxigênio , Receptores Toll-Like/metabolismo
7.
Anal Sci ; 39(10): 1719-1726, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37405629

RESUMO

Designing ratiometric sensors for cysteine (Cys) monitoring with high accuracy is of great significance for disease diagnosis and biomedical studies. The current ratiometric methods mainly rely on multiplex probes, which not only complicates the operation but also increases the cost, making it difficult for quantitative Cys detection in resource-limited areas. Herein, one-pot prepared gold nanoclusters (Au NCs) that glow red fluorescent were synthesized by employing glutathione as the stabilizer and reducing agent. When Fe3+ is present with Au NCs, the fluorescence is quenched and the scattering is strong because of the aggregation of Au NCs. With introduction of Cys, Cys can efficiently compete with glutathione-modified Au NCs for Fe3+, which leads to increase of fluorescence and decrease of scattering. The ratiometric determination of Cys can be thereby realized by collecting the fluorescence and SRS spectrum simultaneously. The linear range for Cys was 5-30 µM with a detection limit of 1.5 µM. In addition, the sensing system exhibits good selectivity for Cys and shows potential application in biological samples.


Assuntos
Cisteína , Nanopartículas Metálicas , Espectrometria de Fluorescência/métodos , Ouro , Corantes Fluorescentes , Glutationa , Limite de Detecção
8.
Talanta ; 264: 124745, 2023 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-37290332

RESUMO

Liquid chromatography-mass spectrometry (LC-MS) is a platform for urine and blood sample analysis. However, the high variability in the urine sample reduced the confidence of metabolite identification. Therefore, pre and post-calibration operations are inevitable to ensure an accurate urine biomarker analysis. In this study, the phenomenon of a higher creatinine concentration variable in ureteropelvic junction obstruction (UPJO) patient urine samples than in healthy people was revealed, indicating the urine biomarker discovery of UPJO patients is not adapted to the creatinine calibrate strategy. Therefore, we proposed a pipeline "OSCA-Finder" to reshape the urine biomarker analysis. First, to ensure a more stable peak shape and total ion chromatography, we applied the product of osmotic pressure and injection volume as a calibration principle and integrated it with an online mixer dilution. Therefore, we obtained the most peaks and identified more metabolites in a urine sample with peak area group CV<30%. A data-enhanced strategy was applied to reduce the overfit while training a neural network binary classifier with an accuracy of 99.9%. Finally, seven accurate urine biomarkers combined with a binary classifier were applied to distinguish UPJO patients from healthy people. The results show that the UPJO diagnostic strategy based on urine osmotic pressure calibration has more potential than ordinary strategies.


Assuntos
Aprendizado Profundo , Nefropatias , Obstrução Ureteral , Humanos , Creatinina/urina , Metabolômica/métodos , Biomarcadores/urina , Obstrução Ureteral/cirurgia , Obstrução Ureteral/urina
9.
Luminescence ; 38(8): 1458-1464, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37222209

RESUMO

Sensing of pyrophosphate ion (PPi) has received much attention due to the strong demand for clinical diagnostics. Here, based on gold nanoclusters (Au NCs), a ratiometric optical detection method for PPi is developed by simultaneously detecting the dual signals of fluorescence (FL) and second-order scattering (SOS). The PPi is detected by inhibiting the formation of aggregates of Fe3+ with Au NCs. Binding of Fe3+ to Au NCs causes aggregation of Au NCs, which leads to fluorescence quenching and scattering increasing. The presence of PPi can competitively bind Fe3+ to re-disperse the Au NCs and finally recover the fluorescence and reduce the scattering signal. The designed PPi sensor shows a high sensitivity with a linear range 5-50 µM and a detection limit of 1.2 µM. In addition, the assay has excellent selectivity for PPi, which makes its application in real biological samples extremely valuable.


Assuntos
Ouro , Nanopartículas Metálicas , Limite de Detecção , Difosfatos , Espectrometria de Fluorescência/métodos , Corantes Fluorescentes
10.
Biomacromolecules ; 24(3): 1184-1193, 2023 03 13.
Artigo em Inglês | MEDLINE | ID: mdl-36808988

RESUMO

Polyurethane materials will come into contact with different solvents in daily life, and at the same time, they will be subject to different degrees of collision, wear and tear. Failure to take corresponding preventative or reparative measures will result in a waste of resources and an increase in costs. To this end, we prepared a novel polysiloxane with isobornyl acrylate and thiol groups as side groups, which was further used in the preparation of poly(thiourethane-urethane) materials. Thiourethane bonds generated by the click reaction of thiol groups with isocyanates endow poly(thiourethane-urethane) materials with the ability to heal and reprocess. Isobornyl acrylate with a large sterically hindered rigid ring promotes segment migration, accelerating the exchange of thiourethane bonds, which is beneficial to the recycling of materials. These results not only promote the development of terpene derivative-based polysiloxanes but also show the great potential of thiourethane as a dynamic covalent bond in the field of polymer reprocessing and healing.


Assuntos
Acrilatos , Siloxanas , Poliuretanos/química , Compostos de Sulfidrila
11.
J Colloid Interface Sci ; 631(Pt B): 239-248, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36401931

RESUMO

Recently, conductive composites have been used in flexible electronic devices and have attracted attention. The integration of self-healing, high sensitivity, large tensile strength, environmental stability, and easy recyclability into conductive composites is very desirable yet challenging. Hence, a conductive composite as a flexible strain sensor with a self-healing and recyclability is facilely developed, with a polyurethane (PU) elastomer bearing dynamic boronic ester as the polymer matrix and carbon nanotubes (CNTs) as a conductive filler. Due to the dynamic boronic ester bond and hydrogen bond, the prepared polyurethane conductive composite has good self-healing and mechanical properties. It not only has a high healing efficiency of 78 % but also has a tensile strength of 15.4 MPa and an elongation at break of 420 %. In addition, the prepared conductive composite has high conductivity (0.57 mS/cm) and sensitivity. As a wearable sensor, it can identify human activities in all directions, such as elbow and finger bending, speaking, and facial changes. Consequently, the polyurethane conductive composite prepared in this study exhibited wonderful application potential in wearable electronic devices such as self-healing strain sensors.


Assuntos
Nanotubos de Carbono , Dispositivos Eletrônicos Vestíveis , Humanos , Poliuretanos , Condutividade Elétrica , Ésteres
12.
Chin Geogr Sci ; 32(5): 896-914, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36091643

RESUMO

Accelerating the promotion of high-quality development of tourism (HQDT) is of great significance to the sustainable development of tourism. This paper defined the concept of HQDT, and then built an evaluation system for HQDT measurement to analyze the spatio-temporal evolution characteristics of China's HQDT based on provincial panel data from 2010 to 2019, using Geodetector to explore the similarities and differences between driving factors of HQDT and tourism development scale (TDS). The results show that: 1) Taking the development concepts of innovation, coordination, green, openness and sharing as the guidance, and considering the organic unity of quantity and quality, the evaluation index system of the HQDT consists of six dimensions of economic stability, innovation driving, coordination and linkage, green and sustainability, openness and cooperation, and sharing and harmony, which respectively represent the basis, momentum, means, orientation, direction and purpose of the HQDT; 2) The level of China's HQDT shows an upward trend, presenting the characteristics of eastern region > central region > western region > northeastern region in 2019. The regional differences in China's HQDT show a downward trend, and the intra-regional differences have replaced the inter-regional differences as the main source of regional differences; 3) China's HQDT shows the characteristics of higher in the east and lower in the west along the Hu line, while the improvement speed of HQDT shows the characteristics of faster in the west and slower in the east, making the decline of east-west differentiation of China's HQDT and the movement of the gravity center towards southwest; 4) Both HQDT and TDS are obviously driven by tourism capital investment and regional consumption. In terms of differences, the HQDT is more driven by government guidance, innovation driving force, and opening up, while the main driving factors of TDS are more biased toward capital elements and hardware facilities, including informatization, tourism resource, traffic, and eco-environment.

13.
Int J Biol Macromol ; 191: 483-491, 2021 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-34562535

RESUMO

In this work, a kind of MOF MIL-100(Fe)@CNFs hydrogel (MC) based on TEMPO-oxidized cellulose nanofibers (CNFs) for fertilizers slow-release was prepared by free-radical polymerization, where N-vinyl caprolactam (NVCL) and CNFs were involved to exhibit temperature and pH response, respectively. Particularly, porous MIL-100(Fe), a kind of metal organic frameworks (MOFs), was introduced to optimize the load and slow-release capabilities. The Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and thermogravimetric analysis were used to characterize. The swelling behaviors and water-retention capabilities of hydrogels were evaluated. Using urea as the model fertilizer, the slow-release mechanism was revealed. Wheat was used as the model crop to evaluate the practical growth status. Compared with MC-0% hydrogels, the MC-10% hydrogels exhibited a better swelling capacity (37 g/g), water-retention (22.78%) and slow-release performance (40.84%). It also exhibited sensitivities to temperature and pH for regulating urea release. Besides, the number of tillers and leaves of wheat fertilized with MC hydrogels significantly increased, as did the photosynthetic rate. In conclusion, the MC-0% hydrogels had a positive influence on crops growth, and promoted the possible utilization of hydrogels in slow-release fertilizers.


Assuntos
Celulose Oxidada/química , Fertilizantes , Hidrogéis/química , Estruturas Metalorgânicas/química , Nanofibras/química , Materiais Inteligentes/química , Liberação Controlada de Fármacos , Concentração de Íons de Hidrogênio , Piperidinas/química , Temperatura
14.
Int J Biol Macromol ; 183: 1911-1924, 2021 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-34097955

RESUMO

Hydrogels have great potential in food packaging. However, stimuli-responsive preservative delivery-based hydrogels for emerging active packaging have not yet been explored. Herein, Unprecedented pH/temperature-responsive hydrogel films for emerging active climacteric fruit packaging were developed based on TEMPO-oxidized nanofibrillated cellulose (TOCNFs) from wheat straw with food-grade cationic-modified poly(N-isopropyl acrylamide-co-acrylamide) (CPNIPAM-AM). TOCNF incorporation into CPNIPAM-AM revealed desirable enhancement of characterization, antimicrobial properties, and pH/thermal-responsive behaviour. In-vitro delivery and release mechanism studies with natamycin revealed the fastest release rates in preferred low pH media, up to 32.1 times higher than that under neutral conditions via anomalous diffusion. Applying a thermal stimulus increased natamycin release rates, providing 1.5-21% gradual-additional pulses by Fickian diffusion. The final hydrogel film showed efficient decay control in response to stimuli of the climacteric fruit environment with safe, recyclable, and feasible application demonstrating the significant potential to be used as an alternative-sustainable material for stimuli-triggered preservative delivery in climacteric fruit packaging.


Assuntos
Anti-Infecciosos/química , Antioxidantes/química , Óxidos N-Cíclicos/química , Metilgalactosídeos/química , Embalagem de Alimentos , Temperatura Alta , Concentração de Íons de Hidrogênio , Nanofibras , Triticum/química
15.
Gastroenterol Nurs ; 43(3): 232-240, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32487955

RESUMO

The aims and objectives of this study were to (1) analyze the bibliometric characteristics of articles on Web of Science from 1986 to the present using literature mining and information visualization technologies developed by CiteSpace software, (2) reflect the current situation in this field as far as possible, and (3) provide evidence for improving research on nursing and clinical liver cirrhosis in Mainland China. No bibliometric analysis exists on Web of Science regarding cirrhosis nursing research. The status of current research, including hotspots and trends, has been assessed in this study through a bibliometric analysis. Literature related to cirrhosis and nursing was identified via Web of Science. Data were then analyzed using CiteSpace software. From 1986 to 2018, a total of 179 articles were published in 109 journals by 830 researchers in 36 countries/regions. The terms "cirrhosis," "management," and "quality of life" emerged most frequently and indicated the hotspots in liver cirrhosis nursing literature. Among all countries/regions, the United States contributed the most research overall; Asia also played an important role in the field of liver cirrhosis nursing research. The journal Gastroenterology Nursing published the greatest number of articles. Liver cirrhosis nursing research has attracted increasing amounts of attention around the world, although it remains less robust than other fields. Cirrhosis nursing research is still in its infancy in Mainland China, and there is an urgent need for additional support from government or research institutions to improve this research focus and promote international acceptance of the research outcomes.


Assuntos
Bibliometria , Cirrose Hepática , Pesquisa em Enfermagem , Humanos
16.
Int J Biol Macromol ; 156: 1418-1424, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31760000

RESUMO

The removal of arsenic from reservoirs is a matter of great concern in many parts of the world. Since adsorption is one of the most effective methods for treating arsenic-containing media, iron oxide nanorods were prepared using cellulose nanocrystals (CNs) as a template to remove this harmful metal from aqueous solutions. X-ray diffraction (XRD) analysis showed that Fe(OH)3 was formed in the initial stage of the hydrothermal reaction, and Fe(OH)3 was transformed into Fe2O3 as the hydrothermal reaction proceeded. Transmission electron microscopy (TEM) analysis showed that the length of the iron oxide nanorods was nearly 200 nm, and the width was 10 nm. Moreover, adsorption property studies showed that the maximal amount of As(III) and As(V) adsorption, corresponding to levels of 13.866 mg/g and 15.712 mg/g, occurred at pH levels of 7 and 3, respectively. The adsorption process conformed to the quasi-second-order kinetic and Langmuir adsorption isotherm models, indicating that the adsorption process consists of a chemical adsorption of monolayers. The results indicate that this composite can be used as a potential adsorbent for treatment of water containing harmful substances.


Assuntos
Arsênio/isolamento & purificação , Celulose/química , Ferro/química , Nanocompostos/química , Nanopartículas/química , Nanotubos/química , Purificação da Água/métodos , Adsorção , Arsênio/química , Concentração de Íons de Hidrogênio , Poluentes Químicos da Água/química , Poluentes Químicos da Água/isolamento & purificação
17.
ACS Omega ; 4(7): 11921-11927, 2019 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-31460303

RESUMO

α-Pinene-modified triethoxysilane (α-PTES) was synthesized by hydrosilylation in the presence of Karstedt's catalyst. The structure of α-PTES was determined by Fourier transform infrared spectroscopy and nuclear magnetic resonance. Under the catalysis of an organotin catalyst, α-PTES, which was the cross-linking agent, and the hydroxy-terminated poly(dimethylsiloxane) matrix were utilized to prepare the room-temperature vulcanized silicone rubber. Morphology, thermal performance, and mechanical properties of the modified silicone rubber were investigated by scanning electron microscopy, thermal gravimetric analysis, dynamic mechanical analysis, and a universal testing machine. Because of the strong rigidity of the ring structure of α-pinene, the thermal and mechanical properties of modified silicone rubber were improved greatly than those of the silicone rubber, and the cross-linking agent of which was methyltriethoxysilane. Results showed that the tensile strength and the break at elongation increased by 69.2 and 125%, respectively, and they are nearly doubled compared to the unmodified silicone rubber.

18.
J Agric Food Chem ; 67(2): 637-643, 2019 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-30601645

RESUMO

The absorbent materials synthesized from biosources with low cost and high selectivity for oils and organic solvents have attracted increasing attention in the field of oil spillage and discharge of organic chemicals. We developed a convenient surface-grafting method to prepare efficient and recyclable biobased aerogels from epoxidized soybean oil (ESO)-modified cellulose at room temperature. The porous network-like structure of the cellulose aerogel was still fully retained after undergoing hydrophobic modification with ESO. Moreover, the modified aerogels possessed excellent hydrophobicity with a water contact angle of 132.6°. Moreover, the absorbent ability of the hydrophobic cellulose aerogels was systematically assessed. The results showed that modified aerogels could retain more than 90% absorption capacity even after 30 absorption-desorption cycles, indicating that the ESO-grafted cellulose aerogels have practical applications in the oil-water separation from industrial wastewater and oil-leakage removal.


Assuntos
Celulose/química , Géis/química , Óleos/química , Óleo de Soja/química , Purificação da Água/instrumentação , Interações Hidrofóbicas e Hidrofílicas , Poluição por Petróleo/análise , Porosidade , Poluentes Químicos da Água/química
19.
J Chromatogr Sci ; 52(10): 1233-8, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24448668

RESUMO

A composite chiral stationary phase (CSP) derived from bovine serum albumin (BSA) and ß-cyclodextrin (CD)-bonded silica was prepared. 2,4,6-Trichloro-1,3,5-triazine was used as a cross-linker. The obtained CSP was applied to the enantioseparation of tryptophan, hydrobenzoin, phenylalanine and mandelic acid. The influences of eluent pH value, organic modifier and column temperature on the retention and enantioseparation were discussed. Tryptophan and hydrobenzoin achieved excellent resolution on the composite CSP. For tryptophan, the highest selectivity, 2.79, was achieved with 1% of methanol at pH 8.0. For hydrobenzoin, the selectivity could reach 1.42. The chromatographic results were compared with that on ß-CD-bonded or BSA-immobilized CSP.


Assuntos
Cromatografia Líquida/instrumentação , Soroalbumina Bovina/química , Dióxido de Silício/química , beta-Ciclodextrinas/química , Animais , Benzoína/análogos & derivados , Benzoína/química , Benzoína/isolamento & purificação , Bovinos , Concentração de Íons de Hidrogênio , Ácidos Mandélicos/química , Ácidos Mandélicos/isolamento & purificação , Modelos Químicos , Fenilalanina/química , Fenilalanina/isolamento & purificação , Estereoisomerismo , Termodinâmica , Triazinas/química , Triptofano/química , Triptofano/isolamento & purificação
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