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1.
Int J Mol Sci ; 25(9)2024 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-38731960

RESUMO

Due to a large number of harmful chemicals flowing into the water source in production and life, the water quality deteriorates, and the use value of water is reduced or lost. Biochar has a strong physical adsorption effect, but it can only separate pollutants from water and cannot eliminate pollutants fundamentally. Photocatalytic degradation technology using photocatalysts uses chemical methods to degrade or mineralize organic pollutants, but it is difficult to recover and reuse. Woody biomass has the advantages of huge reserves, convenient access and a low price. Processing woody biomass into biochar and then combining it with photocatalysts has played a complementary role. In this paper, the shortcomings of a photocatalyst and biochar in water treatment are introduced, respectively, and the advantages of a woody biochar-based photocatalyst made by combining them are summarized. The preparation and assembly methods of the woody biochar-based photocatalyst starting from the preparation of biochar are listed, and the water treatment efficiency of the woody biochar-based photocatalyst using different photocatalysts is listed. Finally, the future development of the woody biochar-based photocatalyst is summarized and prospected.


Assuntos
Carbono , Carvão Vegetal , Purificação da Água , Madeira , Purificação da Água/métodos , Carvão Vegetal/química , Catálise , Madeira/química , Carbono/química , Poluentes Químicos da Água/química , Processos Fotoquímicos , Adsorção
2.
Int J Mol Sci ; 24(11)2023 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-37298624

RESUMO

As the focus of architecture, furniture, and other fields, wood has attracted extensive attention for its many advantages, such as environmental friendliness and excellent mechanical properties. Inspired by the wetting model of natural lotus leaves, researchers prepared superhydrophobic coatings with strong mechanical properties and good durability on the modified wood surface. The prepared superhydrophobic coating has achieved functions such as oil-water separation and self-cleaning. At present, some methods such as the sol-gel method, the etching method, graft copolymerization, and the layer-by-layer self-assembly method can be used to prepare superhydrophobic surfaces, which are widely used in biology, the textile industry, national defense, the military industry, and many other fields. However, most methods for preparing superhydrophobic coatings on wood surfaces are limited by reaction conditions and process control, with low coating preparation efficiency and insufficiently fine nanostructures. The sol-gel process is suitable for large-scale industrial production due to its simple preparation method, easy process control, and low cost. In this paper, the research progress on wood superhydrophobic coatings is summarized. Taking the sol-gel method with silicide as an example, the preparation methods of superhydrophobic coatings on wood surfaces under different acid-base catalysis processes are discussed in detail. The latest progress in the preparation of superhydrophobic coatings by the sol-gel method at home and abroad is reviewed, and the future development of superhydrophobic surfaces is prospected.


Assuntos
Indústrias , Madeira , Catálise , Nanopartículas em Multicamadas , Molhabilidade
3.
Opt Express ; 28(23): 34337-34345, 2020 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-33182906

RESUMO

The behavior of directly linearly polarized emission was investigated in an isotropic Nd:YAG laser with a weakly anisotropic Fabry-Perot cavity. In order to explore the polarization mechanism, the intracavity eigenmodes were analyzed theoretically. A theoretical model was developed and shown to be suitable for describing the orientation-dependent beam profiles of the polarizer-specific features observed in experiments. This model indicates that the linear polarization emission results from the coherently combined state of intracavity eigenmodes as opposed to an intrinsic polarization state. The coherent combination is attributed to the frequency degeneracy and spontaneous phase locking of polarized eigenmodes. For the first time, the polarization coupling mechanism based on the coherent combination of eigenmodes in an isotropic solid-state laser was demonstrated. Moreover, this study also contributes an effective method to judge different types of linear polarization states.

4.
Tumour Biol ; 37(8): 10643-52, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26867766

RESUMO

The use of cytolytic peptides with potential therapeutic properties is a promising approach to cancer therapy due to their convenient automated synthesis and their capacity for modifications. However, the use of cytolytic peptides is limited due to their nonspecific cytolytic activity. In this study, we designed a tumor-targeting proapoptotic system based on an amphipathic D-amino acid-modified apoptotic peptide, KLA, a variant of (KLAKLAK)2, which is fused with a linear tumor-penetrating homing peptide iRGD through specific cathepsin B (CTSB) cleavage sequences that are overexpressed in many types of tumor tissues. Our data show that the procytotoxic peptide D(KLAKLAKKLAKLA)K-GG-iRGD (m(KLA)-iRGD) is internalized into cultured tumor cells through a neuropilin-1 (NRP1)-activated pathway by iRGD delivery. Once inside the cells, the peptide triggers rapid apoptosis through both the mitochondrial-induced apoptotic pathway and the death receptor pathway in NRP1+/αvß3/CTSB+ tumor cells. Furthermore, m(KLA)-iRGD spread extensively within the tumor tissue when it was injected into 4T1 tumor-bearing mice. The m(KLA)-iRGD peptide inhibited tumor growth to a certain degree, resulting in a significant reduction in tumor volume (P < 0.05) and the total inhibition of metastasis at the end of the treatment. These results suggest that m(KLA)-iRGD has the potential for development as a new antitumor drug.


Assuntos
Antineoplásicos/uso terapêutico , Apoptose/efeitos dos fármacos , Catepsina B/metabolismo , Peptídeos Penetradores de Células/uso terapêutico , Neoplasias Mamárias Experimentais/tratamento farmacológico , Oligopeptídeos/administração & dosagem , Pró-Fármacos/uso terapêutico , Ativação Metabólica , Sequência de Aminoácidos , Animais , Antineoplásicos/administração & dosagem , Antineoplásicos/farmacocinética , Neoplasias da Mama/patologia , Divisão Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Peptídeos Penetradores de Células/administração & dosagem , Peptídeos Penetradores de Células/farmacocinética , Portadores de Fármacos/administração & dosagem , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Humanos , Neoplasias Mamárias Experimentais/patologia , Melanoma Experimental/patologia , Camundongos , Camundongos Endogâmicos BALB C , Mitocôndrias/efeitos dos fármacos , Metástase Neoplásica , Neuropilina-1/fisiologia , Pró-Fármacos/administração & dosagem , Pró-Fármacos/farmacocinética , Receptor fas/fisiologia
5.
Polymers (Basel) ; 16(13)2024 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-39000804

RESUMO

The efficient exploitation of planted fast-growing wood is crucial for enhancing wood resource utilization. In this study, the fast-growing poplar wood was modified by in situ impregnation through vacuum impregnation with polyvinyl alcohol and nano-silica sol as impregnation modifiers, combined with delignification-freezing pretreatment. The samples were characterized by FTIR, XRD, SEM, and the universal mechanical testing machine. The results showed that the wrinkle deformation and cracking of the wood blocks were greatly alleviated after the delignification-freezing pretreatment and the polyvinyl alcohol and nano-silica sol were successfully integrated into the wood. The resulting polyvinyl alcohol-silica sol poplar composites exhibited about 216%, 80% and 43% higher compressive strength with respect to delignified wood, natural wood and impregnated natural wood, respectively, thereby demonstrating superior mechanical properties and potential opportunities for value-added and efficient utilization of low-quality wood.

6.
PLoS One ; 19(5): e0301617, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38758776

RESUMO

BACKGROUND: In order to gain a deeper understanding of the relationship between physical activity and adolescent mental health in the post COVID-19 pandemic era, self-esteem and social anxiety were used as mediating variables to explore the potential mechanisms by which physical activity affects adolescent mental health. METHODS: The study used the HELP-II Health Promoting Lifestyle Scale, the SPIN Social Phobia Scale, the Self-Esteem Scale, and the 10-item Kessler Psychological Distress Scale to administer questionnaires to 400 Chinese secondary school students, and SPSS 26.0 and PROCESS 3.3 were used to process the data. RESULTS: The findings showed that (1) physical activity was significantly and positively associated with mental health; (2) self-esteem and social anxiety played a fully mediating role between physical activity and adolescent mental health respectively; (3) self-esteem and social anxiety played a chain mediating role between physical activity and adolescent mental health. CONCLUSION: This study reveals the relationship and influencing mechanism between physical activity and adolescent mental health in the post COVID-19 pandemic era. Appropriate interventions for physical activity, self-esteem, and social anxiety may be beneficial to adolescent mental health. The protective role of self-esteem in adolescent mental health should be the focus of future studies, and further investigations into the association between the COVID-19 and adolescent mental health are warranted.


Assuntos
Ansiedade , COVID-19 , Exercício Físico , Saúde Mental , Autoimagem , Humanos , Adolescente , Feminino , COVID-19/psicologia , COVID-19/epidemiologia , Masculino , Exercício Físico/psicologia , Ansiedade/psicologia , Inquéritos e Questionários , SARS-CoV-2 , Estudantes/psicologia , China/epidemiologia , Fobia Social/psicologia , Pandemias
7.
Chem Biol Drug Des ; 103(2): e14436, 2024 02.
Artigo em Inglês | MEDLINE | ID: mdl-38395608

RESUMO

Neuroinflammation contributes to neurological dysfunction in the patients who suffer from subarachnoid hemorrhage (SAH). Isoliquiritigenin (ISL) is a bioactive component extracted from Genus Glycyrrhiza. This work is to investigate whether ISL ameliorates neuroinflammation after SAH. In this study, intravascular perforation of male Sprague-Dawley rats was used to establish a SAH model. ISL was administered by intraperitoneal injection 6 h after SAH in rats. The mortality, SAH grade, neurological score, brain water content, and blood-brain barrier (BBB) permeability were examined at 24 h after the treatment. Expressions of tumor necrosis factor-α, interleukin-6, Iba-1, and MPO were measured by quantitative real-time polymerase chain reaction (qRT-PCR). Besides, the expression levels of NF-κB p65 and NLRP3, ASC, caspase-1, IL-1ß, and IL-18 were analyzed by western blot. The experimental data suggested that ISL treatment could ameliorate neurological impairment, attenuate brain edema, and ameliorate BBB injury after SAH in rats. ISL treatment repressed the expression of proinflammatory cytokines TNF-α and IL-6, and meanwhile inhibited the expression of Iba-1 and MPO. ISL also repressed NF-κB p65 expression as well as the transport from the cytoplasm to the nucleus. In addition, ISL significantly suppressed the expression levels of NLR family pyrin domain containing 3 (NLRP3), ASC, caspase-1, IL-1ß, and IL-18. These findings suggest that ISL inactivates NLRP3 pathway by inhibiting NF-κB p65 translocation, thereby repressing the neuroinflammation after SAH, and it is a potential drug for the treatment of SAH.


Assuntos
Lesões Encefálicas , Chalconas , Hemorragia Subaracnóidea , Humanos , Ratos , Masculino , Animais , NF-kappa B/metabolismo , Hemorragia Subaracnóidea/complicações , Hemorragia Subaracnóidea/tratamento farmacológico , Inflamassomos/metabolismo , Ratos Sprague-Dawley , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Interleucina-18/uso terapêutico , Doenças Neuroinflamatórias , Lesões Encefálicas/tratamento farmacológico , Lesões Encefálicas/metabolismo , Lesões Encefálicas/patologia , Fator de Necrose Tumoral alfa/genética , Caspases/uso terapêutico
8.
Front Plant Sci ; 14: 1154535, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37089635

RESUMO

Purple corn (Zea mays L.) is a special variety of corn, rich in a large amount of anthocyanins and other functional phytochemicals, and has always ranked high in the economic benefits of the corn industry. However, most studies on the stability of agronomic traits and the interaction between genotype and environment in cereal crops focus on yield. In order to further study the accumulation and stability of special anthocyanins in the growth process of purple corn, this review starts with the elucidation of anthocyanins in purple corn, the biosynthesis process and the gene regulation mechanism behind them, points out the influence of anthocyanin metabolism on anthocyanin metabolism, and introduces the influence of environmental factors on anthocyanin accumulation in detail, so as to promote the multi-field production of purple corn, encourage the development of color corn industry and provide new opportunities for corn breeders and growers.

9.
Front Plant Sci ; 14: 1151131, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37615025

RESUMO

As the most suitable potential clean energy power generation technology, biophotovoltaics (BPV) not only inherits the advantages of traditional photovoltaics, such as safety, reliability and no noise, but also solves the disadvantages of high pollution and high energy consumption in the manufacturing process, providing new functions of self-repair and natural degradation. The basic idea of BPV is to collect light energy and generate electric energy by using photosynthetic autotrophs or their parts, and the core is how these biological materials can quickly and low-loss transfer electrons to the anode through mediators after absorbing light energy and generating electrons. In this mini-review, we summarized the biological materials widely used in BPV at present, mainly cyanobacteria, green algae, biological combinations (using multiple microorganisms in the same BPV system) and isolated products (purified thylakoids, chloroplasts, photosystem I, photosystem II), introduced how researchers overcome the shortcomings of low photocurrent output of BPV, pointed out the limitations that affected the development of BPV' biological materials, and put forward reasonable assumptions accordingly.

10.
Front Bioeng Biotechnol ; 10: 1033514, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36324886

RESUMO

Nature is the source of human design inspiration. In order to adapt to the environment better, creatures in nature have formed various morphological structures during billions of years of evolution, among which the superhydrophobic characteristics of some animal and plant surface structures have attracted wide attention. At present, the preparation methods of bionic superhydrophobic surface based on the microstructure of animal and plant body surface include vapor deposition, etching modification, sol-gel method, template method, electrostatic spinning method and electrostatic spraying method, etc., which have been used in medical care, military industry, shipping, textile and other fields. Based on nature, this paper expounds the development history of superhydrophobic principle, summarizes the structure and wettability of superhydrophobic surfaces in nature, and introduces the characteristics differences and applications of different superhydrophobic surfaces in detail. Finally, the challenge of bionic superhydrophobic surface is discussed, and the future development direction of this field is prospected.

11.
Front Bioeng Biotechnol ; 10: 958095, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35992341

RESUMO

As an emerging fringe science, bionics integrates the understanding of nature, imitation of nature, and surpassing nature in one aspect, and it organically combines the synergistic complementarity of function and structure-function integrated materials which is of great scientific interest. By imitating the microstructure of a natural biological surface, the bionic superhydrophobic surface prepared by human beings has the properties of self-cleaning, anti-icing, water collection, anti-corrosion and oil-water separation, and the preparation research methods are increasing. The preparation methods of superhydrophobic surface include vapor deposition, etching modification, sol-gel, template, electrostatic spinning, and electrostatic spraying, which can be applied to fields such as medical care, military industry, ship industry, and textile. The etching modification method can directly modify the substrate, so there is no need to worry about the adhesion between the coating and the substrate. The most obvious advantage of this method is that the obtained superhydrophobic surface is integrated with the substrate and has good stability and corrosion resistance. In this article, the different preparation methods of bionic superhydrophobic materials were summarized, especially the etching modification methods, we discussed the detailed classification, advantages, and disadvantages of these methods, and the future development direction of the field was prospected.

12.
Polymers (Basel) ; 14(15)2022 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-35956687

RESUMO

The polyethylene terephthalate (PET) beverage bottle is one of the most common beverage packages in the world, but the bottom of the PET bottle tends to crack due to excessive stress. In this paper, through numerical simulation and finite element analysis, the mechanical properties of four typical geometric models of bottle bottom are studied, and it is determined that "claw flap bottle bottom (CF-bottom)" has the best structure. Then, the shapes of four bottle bottom structures are fine-tuned by using the automatic optimization method. Under the premise of the same material quality, the surface maximum principal stress, the overall maximum principal stress, and the total elastic strain energy of the bottle bottom are reduced by 46.39-71.81%, 38.16-71.50%, and 38.56-61.38%, respectively, while the deformation displacement is also reduced by 0.63 mm-3.43 mm. In contrast to other papers, this paper dispenses with the manual adjustment of various variables, instead adopting automatic shape optimization to obtain a more accurate model. The percentage of maximum principal stress reduction is remarkable, which provides a feasible theoretical guidance for the structural optimization of PET bottle bottom in the production process.

13.
Polymers (Basel) ; 14(14)2022 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-35890620

RESUMO

PET bottlesare often used as airtight containers for filling carbonated drinks. Because carbonated drinks contain large volumes of CO2 gas, the container needs to bear a tremendous pressure from the inside of the bottle.If the stress exceeds the bearing limit, the material will show the phenomenon of local cracking and liquid overflow.For the structural design, the method of manual adjustment before automatic adjustment was adopted. First, through manual optimization, the initial optimal parameter combination was as follows:the inner diameter of the bottle bottom was 17 mm, the dip angle of the valley bottom was 81°, the deepest part of the valley bottom was 25 mm, and the outer diameter was 27 mm. Comsol software was used for automatic optimization. Compared with the original bottle bottom, the total maximum principal stress and total elastic strain energy in the bottle bottom after manual-automatic double optimization decreased by 69.4% and 40.0%, respectively, and the displacement caused by deformation decreased by 0.60 mm (74.1%). The extremely high reduction ratio was caused by manual-automatic double optimization.

14.
Polymers (Basel) ; 14(16)2022 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-36015621

RESUMO

Compared with other materials, polyethylene terephthalate (PET) has high transparency, excellent physical and mechanical properties in a wide temperature range and good hygiene and safety, so it is widely used in the packaging industry, especially in the packaging of beverages and foods. The optimization of PET bottles is mainly reflected in three aspects: material optimization, structure optimization and process optimization, among which there is much research on material optimization and process optimization, but there is no complete overview on structure optimization. A summary of structural optimization is necessary. Aiming at structural optimization, the finite element method is a useful supplement to the beverage packaging industry. By combining the computer-aided design technology and using finite element software for finite element simulation, researchers can replace the experimental test in the pre-research design stage, predict the effect and save cost. This review summarizes the development of PET bottles for beverage packaging, summarizes various optimization methods for preventing stress cracking in beverage packaging, and especially focuses on comparing and evaluating the effects of several optimization methods for packaging structure. Finally, the future development of all kinds of optimization based on structural optimization in the field of beverage packaging is comprehensively discussed, including personalized design, the combination of various methods and the introduction of actual impact factor calculation.

15.
ACS Appl Mater Interfaces ; 14(49): 54662-54669, 2022 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-36459617

RESUMO

Sodium-sulfur batteries operating at ambient temperature are being extensively studied because of the high theoretical capacity and abundant resources, yet the long-chain polysulfides' shuttle effect causes poor cycling performance of Na-S batteries. We report an annealing/etching method to converse low-cost wheat bran to a 3D honeycomb-like carbon with abundant micropores (WBMC), which is smaller than S8 molecular size (∼0.7 nm). Thus, the microporous structure could only fill small molecular sulfur (S2-4). The micropores made sulfur a one-step reaction without the shuttle effect due to the formed short-chain polysulfides being insoluble. The WBMC@S exhibits an excellent initial capacity (1413 mAh g-1) at 0.2 C, outstanding cycling performance (822 mAh g-1 after 100 cycles at 0.2 C), and high rate performance (483 mAh g-1 at 3.0 C). The electrochemical performance proves that the steric confinement of micropores effectively terminates the shuttle effect.

16.
Eur J Med Chem ; 191: 112134, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32088493

RESUMO

11ß-hydroxysteroid dehydrogenase type 1 (11ß-HSD1) is a key metabolic enzyme that catalyzing the intracellular conversion of inactive glucocorticoids to physiologically active ones. Work over the past decade has demonstrated the aberrant overexpression of 11ß-HSD1 contributed to the pathophysiological process of metabolic diseases like obesity, type 2 diabetes mellitus, and metabolic syndromes. The inhibition of 11ß-HSD1 represented an attractive therapeutic strategy for the treatment of metabolic diseases. Therefore, great efforts have been devoted to developing 11ß-HSD1 inhibitors based on the diverse molecular scaffolds. This review focused on the structural features of the most important 11ß-HSD1 inhibitors and categorized them into natural products derivatives and synthetic compounds. We also briefly discussed the optimization process, binding modes, structure-activity relationships (SAR) and biological evaluations of each inhibitor. Moreover, the challenges and directions for 11ß-HSD1 inhibitors were discussed, which might provide some useful clues to guide the future discovery of novel 11ß-HSD1 inhibitors.


Assuntos
11-beta-Hidroxiesteroide Desidrogenase Tipo 1/antagonistas & inibidores , Produtos Biológicos/farmacologia , Desenvolvimento de Medicamentos , Inibidores Enzimáticos/farmacologia , Doenças Metabólicas/tratamento farmacológico , 11-beta-Hidroxiesteroide Desidrogenase Tipo 1/metabolismo , Animais , Produtos Biológicos/química , Inibidores Enzimáticos/química , Humanos , Doenças Metabólicas/metabolismo , Estrutura Molecular
17.
Artigo em Chinês | WPRIM | ID: wpr-1016537

RESUMO

ObjectiveTo identify the rate, population characteristics, and vaccination history of repeat infections among previously infected people in the current epidemic based on the rate of repeat infection and population characteristics of different mutant strains at different times in Pudong New Area of Shanghai, and to provide reference for the prevention and control strategies of novel coronavirus repeat infections. MethodsA total of 9 250 investigated subjects were randomly selected from the new cases of asymptomatic infection and confirmed cases reported by Pudong New Area from March to May 2022. The investigation mainly focused on demographic characteristics, nucleic acid or antigen test results, and symptoms after infection. The repeat infection rates among different populations were compared, and logistic regression was used to analyze the impact of gender, age, and vaccination status on repeat infections. ResultsThe survey sample of 9 250 people had a response rate of 81.85%. There were 4 043 males (53.40%) and 3 528 females (46.60%), with a median age of 34 years old (P25, P75: 7, 61). The overall vaccine uptake rate was 59.44% (4 500/7 571). In December of 2022, there were 563 cases of repeat infection, with an infection rate of 7.44%. The lowest rate of repeat infection was seen in the 3‒ year-old group (2.86%) and the highest rate in the 30‒ year-old group (12.42%), with significant differences between different age groups. The repeated infection rate for those who had completed their vaccinations was significantly lower (6.57%) compared to those who had not (7.11%). The age groups of 3‒ years, 70‒79 years, as well as individuals who completed full vaccination and received booster shots were protective factors against repeat infections. ConclusionThe overall rate of reinfection among the infected in Shanghai during the spring of 2022 was low in the outbreak of the Omicron variant, and the rate of reinfection in the 3‒ year-old group was significantly lower than in other age groups. Completing the full course of vaccination significantly reduces the risk of reinfection. Although the reinfection rate is high in individuals who received booster shots, it remains a mitigating factor compared to those who do not receive the vaccine. It is recommended to continue monitoring reinfections in key populations and further strengthen immunization efforts.

18.
Opt Express ; 16(5): 2989-94, 2008 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-18542384

RESUMO

In this paper, a high power blue laser at 447 nm was obtained by intracavity sum-frequency-mixing of a diode-side-pumped Q-switched Nd:YAlO(3)(Nd:YAP) laser operating at 1341.4 nm. A type-I critical phase matching LiB(3)O(5) (LBO) crystal and type-II critical phase matching KTiOPO(4) (KTP) crystal were used for second harmonic generation and third harmonic generation, respectively. The phase matching condition of the KTP crystal was researched. The results show that the KTP has superiority in intracavity sum-frequency-mixing blue light generation. 4.76 W blue light output was achieved at 4.6 kHz with the pulse width of 190ns. The fluctuation of output power was better than 3% at the output power of 4.76 W during half an hour.


Assuntos
Lasers de Estado Sólido , Iluminação/instrumentação , Semicondutores , Cor , Desenho de Equipamento , Análise de Falha de Equipamento , Iluminação/métodos
19.
Artigo em Chinês | WPRIM | ID: wpr-985503

RESUMO

The green fluorescent reporter gene was inserted into the gene interval of polymyxin resistant mcr-1-carrying plasmid (pSH13G841) by homologous recombination of suicide plasmid. At the same time, E. coli J53 with red fluorescent reporter gene was constructed. Using the ability of spontaneous conjugation of drug resistant plasmid (pSH13G841), pSH13G841-GFP plasmid was transferred into J53 RFP bacteria to construct a double fluorescent labeled donor bacterium. The two light-emitting systems could stably and spontaneously express fluorescence without mutual interference. The dual fluorescence report system constructed can be used for visual tracing horizontal transfer of mcr-1-carrying plasmid, the subsequent model can study the colonization, transfer and prognosis of drug-resistant bacteria/drug-resistant genes mcr-1 by using mouse in vivo imaging technology.

20.
Bone ; 41(4): 631-8, 2007 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17652051

RESUMO

BACKGROUND: With osteoporosis emerged as one of the most important health issues, more and more investigations are focusing on osteoporotic fracture healing. However, there are few studies on the changes of microstructure and mineralized tissue of newly formed callus. OBJECTIVE: We established an osteoporotic fracture rat model to evaluate the changes of microstructure and mineralized tissue during osteoporotic fracture healing. MATERIALS AND METHODS: A mid-shaft femur fracture model was established 12 weeks after ovariectomy as an osteoporotic fracture group (OPF group). Femurs were then harvested at 4 weeks, 8 weeks and 12 weeks after fracture for peripheral quantitative computed tomography (pQCT), micro-computed tomography (MicroCT), histology and biomechanical test. A sham-operated group was used for comparison, i.e. the normal fracture group (NF group). RESULTS: The pQCT-derived total external callus area in the OPF group was smaller than that in the NF group at 4 weeks after fracture (P<0.05), whereas it was 21% larger in the OPF group than that in the NF group at 12 weeks after fracture (P<0.01). The pQCT-derived bone mineral density in the OPF group was significantly inferior to the NF group at all the time points (P<0.05 for all the time points, respectively). MicroCT data, at 12 weeks after fracture, showed the total callus, bony callus, and newly formed bone was approximately 20% lower in the OPF group than that in the NP group, and the total connectivity was 56% lower in the OPF group as compared to the NF group. Biomechanical test data, at 12 weeks after fracture, showed that the failure load of the left femur of OPF group was 17% less compared to that of the NF group (P<0.01), and 15% lower bending stiffness (P<0.05), 20% lower bending stress (P<0.01), and 28% lower energy at failure (P<0.01) were observed in the OPF group as compared to the NF group. CONCLUSION: The decrease in mineralized tissue and the not well connected microstructure in newly formed callus may explain the decline of mechanical impairment of fracture healing in the ovariectomized rats.


Assuntos
Densidade Óssea , Consolidação da Fratura , Osteoporose/patologia , Animais , Feminino , Osteotomia , Ratos , Ratos Sprague-Dawley , Estresse Mecânico , Fatores de Tempo , Tomógrafos Computadorizados
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