Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 45
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
País de afiliação
Intervalo de ano de publicação
1.
Sensors (Basel) ; 21(10)2021 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-34069105

RESUMO

Counting the number of work cycles per unit of time of earthmoving excavators is essential in order to calculate their productivity in earthmoving projects. The existing methods based on computer vision (CV) find it difficult to recognize the work cycles of earthmoving excavators effectively in long video sequences. Even the most advanced sequential pattern-based approach finds recognition difficult because it has to discern many atomic actions with a similar visual appearance. In this paper, we combine atomic actions with a similar visual appearance to build a stretching-bending sequential pattern (SBSP) containing only "Stretching" and "Bending" atomic actions. These two atomic actions are recognized using a deep learning-based single-shot detector (SSD). The intersection over union (IOU) is used to associate atomic actions to recognize the work cycle. In addition, we consider the impact of reality factors (such as driver misoperation) on work cycle recognition, which has been neglected in existing studies. We propose to use the time required to transform "Stretching" to "Bending" in the work cycle to filter out abnormal work cycles caused by driver misoperation. A case study is used to evaluate the proposed method. The results show that SBSP can effectively recognize the work cycles of earthmoving excavators in real time in long video sequences and has the ability to calculate the productivity of earthmoving excavators accurately.

2.
Crit Rev Biotechnol ; 40(3): 365-379, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31948287

RESUMO

Chitosan, obtained as a result of the deacetylation of chitin, one of the most important naturally occurring polymers, has antimicrobial properties against fungi, and bacteria. It is also useful in other fields, including: food, biomedicine, biotechnology, agriculture, and the pharmaceutical industries. A literature survey shows that its antimicrobial activity depends upon several factors such as: the pH, temperature, molecular weight, ability to chelate metals, degree of deacetylation, source of chitosan, and the type of microorganism involved. This review will focus on the in vitro and in vivo antimicrobial properties of chitosan and its derivatives, along with a discussion on its mechanism of action during the treatment of infectious animal diseases, as well as its importance in food safety. We conclude with a summary of the challenges associated with the uses of chitosan and its derivatives.


Assuntos
Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Quitina/química , Quitosana/química , Quitosana/farmacologia , Doenças dos Animais/tratamento farmacológico , Animais , Bactérias/efeitos dos fármacos , Biotecnologia , Bovinos , Terapia por Quelação , Indústria Alimentícia , Inocuidade dos Alimentos , Fungos , Concentração de Íons de Hidrogênio , Ostreidae/efeitos dos fármacos , Temperatura , Indústria Têxtil
3.
Sensors (Basel) ; 20(14)2020 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-32660040

RESUMO

Target Tracking (TT) is a fundamental application of wireless sensor networks. TT based on received signal strength indication (RSSI) is by far the cheapest and simplest approach, but suffers from a low stability and precision owing to multiple paths, occlusions, and decalibration effects. To address this problem, we propose an innovative TT algorithm, known as the SVM+KF method, which combines the support vector machine (SVM) and an improved Kalman filter (KF). We first use the SVM to obtain an initial estimate of the target's position based on the RSSI. This enhances the ability of our algorithm to process nonlinear data. We then apply an improved KF to modify this estimated position. Our improved KF adds the threshold value of the innovation update in the traditional KF. This value changes dynamically according to the target speed and network parameters to ensure the stability of the results. Simulations and real experiments in different scenarios demonstrate that our algorithm provides a superior tracking accuracy and stability compared to similar algorithms.

4.
Appl Microbiol Biotechnol ; 103(4): 1557-1571, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30607489

RESUMO

Chitosan is a naturally occurring biodegradable as well as a non-toxic polymer generated from chitin through alkaline deacetylation reaction, and it is insoluble in organic/inorganic solvents and water. Furthermore, chitosan is one of the most plentiful cationic polymers in natural surroundings. Due to its non-toxicity and biocompatibility, chitosan is extensively employed in industrial, biomedical, food, pharmaceutical, environmental, and agricultural industry. Chitosan-based biomaterials exhibit great potential in various biotechnological applications, such as anti-hypertensive therapy, anti-oxidant, anti-microbial, anti-allergic, immunostimulant, cancer therapy, delivery of genetic materials, delivery of bone morphogenetic type-2, wound healing, treatment of wastewater, hypocholesterolemic, and bio-imaging. Therefore, this review mainly focuses on the biotechnological potential of chitosan and its derivatives as well as presents the potential of chitosan-based biomaterial/pharmaceutical for the prevention of various life-threating chronic disorders.


Assuntos
Anticolesterolemiantes/metabolismo , Materiais Biocompatíveis/metabolismo , Biotecnologia/métodos , Quitosana/metabolismo , Tecnologia Farmacêutica/métodos
5.
Sensors (Basel) ; 18(5)2018 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-29695129

RESUMO

This paper presents an effective approach for depth reconstruction from a single image through the incorporation of semantic information and local details from the image. A unified framework for depth acquisition is constructed by joining a deep Convolutional Neural Network (CNN) and a continuous pairwise Conditional Random Field (CRF) model. Semantic information and relative depth trends of local regions inside the image are integrated into the framework. A deep CNN network is firstly used to automatically learn a hierarchical feature representation of the image. To get more local details in the image, the relative depth trends of local regions are incorporated into the network. Combined with semantic information of the image, a continuous pairwise CRF is then established and is used as the loss function of the unified model. Experiments on real scenes demonstrate that the proposed approach is effective and that the approach obtains satisfactory results.


Assuntos
Redes Neurais de Computação
6.
Lasers Surg Med ; 47(4): 306-11, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25864416

RESUMO

BACKGROUND AND OBJECTIVES: In urology, potassium-titanyl-phosphate (KTP) laser is mainly used in the treatment of benign prostatic hyperplasia with a low rate of intraoperative and postoperative complications. A prospective, randomized study was undertaken to investigate the treatment outcomes of KTP laser vaporization for primary non-muscle-invasive bladder tumors (NMIBTs) as compared with conventional monopolar transurethral resection of bladder tumors (TURBT). MATERIALS AND METHODS: This study was designed as a prospective, randomized trial. After institutional review board approval, 229 consecutive patients with NMIBTs were randomized to 2 groups. Among them, 116 patients underwent KTP laser vaporization of a bladder tumor (laser group) and 113 patients underwent standard transurethral electroresection of the bladder tumors using monopolar loop electrode (TURBT group). According to the prognostic factors for recurrence, all patients were divided into low, intermediate or high risk subgroups. The clinical data were recorded and compared between the two groups. RESULTS: Eighty-nine patients in laser group and 94 in TURBT group were evaluable for the study end points. The preoperative characteristics of the patients were comparable in the two groups. There was no statistical difference in operation time between the two groups. Patients in the laser group had fewer perioperative complications and more patients needed bladder irrigation in the TURBT group. Compared with laser group, patients in the TURBT group had longer catheterization time and hospitalization duration. There were no statistical differences in the oncologic results in term of 2-year recurrence rates as compared between the two groups. CONCLUSIONS: Our study demonstrated that using KTP laser, transurethral vaporization is an effective and safe treatment for the patients with primary NMIBT. Compared with traditional TURBT, the KTP laser surgery had fewer perioperative complications and similar oncological results.


Assuntos
Eletrocirurgia/métodos , Terapia a Laser , Lasers de Estado Sólido , Neoplasias da Bexiga Urinária/cirurgia , Feminino , Humanos , Tempo de Internação/estatística & dados numéricos , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia , Hemorragia Pós-Operatória/terapia , Estudos Prospectivos , Irrigação Terapêutica/estatística & dados numéricos , Cateterismo Urinário/estatística & dados numéricos
7.
Zhonghua Nan Ke Xue ; 18(3): 281-3, 2012 Mar.
Artigo em Zh | MEDLINE | ID: mdl-22474997

RESUMO

OBJECTIVE: To investigate the clinical effects of the Chinese traditional medicine Yougui Capsules and Wuziyanzong Pills on sperm viability and motility in patients with oligoasthenospermia. METHODS: A total of 80 infertile men oligoasthenospermia were equally randomized into a trial and a control group, the former treated with Yougui Capsules at 1.68 g tid, while the latter with Wuziyanzong Pills at 6 g bid, both for a course of 12 weeks. The sperm viability and motility of the patients were detected and compared before and after medication. RESULTS: After 12 weeks of medication, the sperm viability and percentages of grade a and grade a + b sperm were (65.7 +/- 13.1), (22.5 +/- 9.1) and (47.6 +/- 15.8)% in the trial group, significantly higher than (38.1 +/- 11.1), (13.2 +/- 6.8) and (24.1 +/- 10.9)% in the control (P<0.05). What's more, the above three parameters of the two groups were also significantly higher than those before medication, which were (31.9 +/- 16.9), (8.2% +/- 3.7) and (15.7 +/- 13.9)% in the former and (31.7 +/- 17.0), (7.9 +/- 4.5) and (16.9 +/- 13.6)% in the latter (P<0.05). CONCLUSION: Both Yougui Capsules and Wuziyanzong Pills can improve sperm viability and motility in patients with oligoasthenospermia, and the former is even more efficacious than the latter.


Assuntos
Astenozoospermia/terapia , Medicamentos de Ervas Chinesas/uso terapêutico , Fitoterapia , Adulto , Humanos , Masculino , Medicina Tradicional Chinesa , Adulto Jovem
8.
Polymers (Basel) ; 14(7)2022 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-35406180

RESUMO

Suture is an important part of surgery, and wounds closing after surgery remains a challenge for postoperative care. Currently, silk, linen fiber, and cotton are available in the market as non-absorbable suture biomaterials. So, there is an urgent need to develop a novel suture with advantageous characteristics compared to the ones available on the market. In present study, a series of ultra-high molecular weight chitosan with different DD and MV were prepared from squid cartilage by alkaline treatment and ultrasonic degradation. The corresponding chitosan monofilaments were prepared by a wet spinning process and were characterized as sutures. The effects of the DD and MV of chitosan on the properties of its monofilament were studied, including surface morphology, mechanical property, swelling ratio, ash content, in vitro enzymatic degradation, and in vitro cytotoxicity. According to the results, AS-85 was chosen to be the best suitable as an absorbable surgical suture, which was spun from squid cartilage chitosan with DD~85% and MV~1.2 × 106. The outcome of the present study might derive tremendous possibilities for the utilization of squid cartilage ß-chitin for biomedical applications.

9.
Exp Ther Med ; 22(5): 1318, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34630672

RESUMO

The aim of the present study was to investigate the expression and role of microRNA-18a-5p (miR-18a-5p) during the formation of hypertrophic scar (HS), and to further explore the molecular mechanisms involved. Downregulation of miR-18a-5p in HS tissues and human HS fibroblasts (hHSFs) was detected by reverse transcription-quantitative polymerase chain reaction. The binding sites between miR-18a-5p and the 3'-untranslated region of SMAD family member 2 (Smad2) were predicted by TargetScan and confirmed by dual-luciferase reporter assay. To investigate the role of miR-18a-5p in HS formation, the effects of miR-18a-5p downregulation or upregulation on hHSFs were subsequently determined. Cell proliferation was detected by an MTT assay, while cell apoptosis was measured by flow cytometry. In addition, the protein expression levels of Smad2, Collagen I (Col I) and Col III were examined by western blot assay. The findings indicated that miR-18a-5p downregulation in hHSFs significantly promoted the cell proliferation, decreased cell apoptosis and enhanced the expression levels of Smad2, Col I and Col III protein and mRNA, whereas miR-18a-5p upregulation in hHSFs exerted opposite effects. Notably, the effects of miR-18a-5p upregulation on hHSFs were eliminated by Smad2 upregulation. In conclusion, the data indicated that miR-18a-5p was downregulated during HS formation, and its upregulation repressed scar fibroblast proliferation and extracellular matrix deposition by targeting Smad2. Therefore, miR-18a-5p may serve as a novel therapeutic target for the treatment of HS.

10.
Carbohydr Polym ; 256: 117577, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33483072

RESUMO

In the field of neurosurgery, timely and effective repair of dura mater plays an important role in stabilizing the physiological functions of the human body. Therefore, the aim of this study is to develop a new type of bilayer membrane as a dural substitute candidate. It consists of a dense layer that prevents cerebrospinal fluid leakage and a porous layer that promotes tissue regeneration. The dense layer, a composite polysaccharid film, was composed of high molecular weight chitosan (CS) and bacterial cellulose (BC). The porous layer, a composite polysaccharid scaffold cross-linked by glutaraldehyde (GA) or citric acid (CA) respectively, was composed of O-carboxymethyl chitin (O-CMCH) and BC. The bilayer dural substitutes were characterized in terms of SEM, mechanical behavior, swelling rate, anti-leakage test, in vitro cytotoxicity, proliferation, and animal experiment. Results indicated that all prepared dural substitutes were tightly bound between layers without excessively large cavities. The porous layer showed appropriate pore size (90~200 µm) with high porous connectivity. The optimized bilayer dural substitutes showed suitable swelling rate and mechanical behavior. Furthermore, no leakage was observed during testing, no cytotoxicity effect on NIH/3T3 cells, and exhibited excellent cell proliferation promoting properties. Also, it was observed that it did not deform in the peritoneal environment of mice, and tissue inflammation was mild.


Assuntos
Celulose/química , Quitina/química , Dura-Máter/patologia , Glutaral/química , Animais , Materiais Biocompatíveis , Proliferação de Células , Quitina/análogos & derivados , Quitosana/química , Ácido Cítrico/química , Humanos , Interações Hidrofóbicas e Hidrofílicas , Inflamação , Camundongos , Microscopia Eletrônica de Varredura , Células NIH 3T3 , Polissacarídeos , Porosidade , Espectroscopia de Infravermelho com Transformada de Fourier , Estresse Mecânico , Alicerces Teciduais/química , Difração de Raios X
11.
Polymers (Basel) ; 13(18)2021 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-34577981

RESUMO

Bone scaffolds based on multi-components are the leading trend to address the multifaceted prerequisites to repair various bone defects. Chitosan is the most useable biopolymer, having excellent biological applications. Therefore, in the present study, the chitosan microsphere was prepared by the ion-gel method; transforming growth factor ß (TGF-ß1) and bone morphogenetic protein 2 (BMP-2) were loaded onto it and then combined with alginate/hyaluronic acid/collagen (Alg/HA/ICol) to construct a jawbones scaffold. The Alg/HA/ICol scaffolds were characterized by FTIR and SEM, and the water content, porosity, tensile properties, biocompatibility, and osteogenic-induced differentiation ability of the Alg/HA/ICol jawbones scaffolds were studied. The results indicate that a three-dimensional porous jawbone scaffold was successfully constructed having 100-250 µm of pore size and >90% of porosity without cytotoxicity against adipose-derived stem cells (ADSCs). Its ALP quantification, osteocalcin expression, and Von Kossamineralized nodule staining was higher than the control group. The jawbones scaffold constructed by TGF-ß1 and BMP-2 loaded chitosan microsphere combining with Alg/HA/ICol has potential biomedical application in the future.

12.
ACS Appl Bio Mater ; 3(9): 6187-6195, 2020 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-35021751

RESUMO

To improve the biocompatibility/biodegradability as well as to lower the cost of the popular glycosaminoglycan/collagen scaffold, a monocomponent's polysaccharide scaffold based on biomimetic chemical modification of chitin from lower organisms was developed creatively. O-Carboxymethyl chitin (O-CMCH) was prepared by chloroacetic acid substitution of alkalized chitin. The cross-linked O-CMCH soft tissue scaffold was constructed by a sol-gel freeze-drying method. The key parameters of the O-CMCH molecular structure, the degree of deacetylation (DD), and the degree of substitution (DS) were used to regulate the morphology and physical properties of the scaffold. The optimized scaffolds were implanted subcutaneously in mice, and the inflammation reaction of surrounding tissues, dermal tissue growth, and scaffold degradation were observed dynamically by light microscopy and scanning electron microscopy. The results showed that the micropores of the scaffold constructed by O-CMCH with DD = 0.53 and DS = 0.61 were uniformly distributed and in communication with each other, and the pore size was 100-150 µm, with high porosity (93.52 ± 4.68%), high swelling ratio (1402 ± 70%), and high skeleton cross-linking degree (93.4 ± 4.6%). Its tensile strength reached 0.183 ± 0.009 MPa, and its elongation at break was 18.7 ± 0.9%. Furthermore, it could be degraded to less than 10% after 16 days in phosphate buffer solution (pH = 7.4) with 0.2 mg/mL lysozymes (≥ 20 000 U/mg). The early inflammation after implanting the optimized scaffolds in mice showed no difference compared with the control. The scaffold material induced dermal tissues to grow over it and was degraded gradually in vivo. The optimized scaffold regulated by DD and DS of O-CMCH possessed suitable morphology and physical properties for soft tissue engineering technology and exhibited a high applicable value.

13.
Colloids Surf B Biointerfaces ; 186: 110734, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31865119

RESUMO

Recently, silver nanoparticles gain significant attention due to their applications in various fields. The aim of present study was to develop the eco-friendly, cost effective, and simple method to biosynthesized the silver nanoparticle using sliver nitrate as precursor. In this study, we investigated the physical characterization and biotechnological applications of biosynthesized silver nanoparticle using exopolysaccharide of probiotic Lactobacillus brevis MSR104 isolated from Chinese koumiss. Biosynthesized silver nanoparticles were characterized using the fourier-transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction analysis, and elemental analyzer. The achieved results indicate that silver nanoparticles varied in sized with an average size of 45 nm. The X-ray diffraction analysis results showed that the silver nanoparticles have a crystalline nature. The results of antimicrobial assay indicated that the silver nanoparticles exhibited outstanding antimicrobial activity in dose dependent manner against both Gram's negative as well as Gram's positive. The antioxidant results indicate that the silver nanoparticles showed excellent scavenging rate against DPPH free radicals (81.4 ±â€¯1.2%) and nitric oxide free radicals (75.06 ±â€¯0.4%). Furthermore, the results of MTT assay revealed that the AgNPs significantly reduced the percentage of live HT-29 cells at higher concentration. This study concluded that the newly synthesized silver nanoparticles have antibacterial, antioxidant, and anticancer applications in agricultural and food industries.


Assuntos
Antibacterianos/farmacologia , Antioxidantes/farmacologia , Kumis/microbiologia , Levilactobacillus brevis/metabolismo , Polissacarídeos/farmacologia , Antibacterianos/biossíntese , Antibacterianos/isolamento & purificação , Antioxidantes/isolamento & purificação , Antioxidantes/metabolismo , Compostos de Bifenilo/antagonistas & inibidores , China , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Levilactobacillus brevis/química , Nanopartículas Metálicas/química , Testes de Sensibilidade Microbiana , Tamanho da Partícula , Picratos/antagonistas & inibidores , Polissacarídeos/biossíntese , Polissacarídeos/química , Polissacarídeos/isolamento & purificação , Prata/química , Prata/metabolismo , Propriedades de Superfície
14.
Nanotechnology ; 20(24): 245101, 2009 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-19468171

RESUMO

In this paper, novel multiaction antibacterial nanofibrous membranes containing apatite, Ag, AgBr and TiO2 as four active components were fabricated by an electrospinning technique. In this antibacterial membrane, each component serves a different function: the hydroxyapatite acts as the adsorption material for capturing bacteria, the Ag nanoparticles act as the release-active antibacterial agent, the AgBr nanoparticles act as the visible sensitive and release-active antibacterial agent, and the TiO2 acts as the UV sensitive antibacterial material and substrate for other functional components. Using E. coli as the typical testing organism, such multicomponent membranes exhibit excellent antimicrobial activity under UV light, visible light or in a dark environment. The significant antibacterial properties may be due to the synergetic action of the four major functional components, and the unique porous structure and high surface area of the nanofibrous membrane. It takes only 20 min for the bacteria to be completely (99.9%) destroyed under visible light. Even in a dark environment, about 50 min is enough to kill all of the bacteria. Compared to the four component system in powder form reported previously, the addition of the electrospun membrane could significantly improve the antibacterial inactivation of E. coli under the same evaluation conditions. Besides the superior antimicrobial capability, the permanence of the antibacterial activity of the prepared free-standing membranes was also demonstrated in repeated applications.


Assuntos
Antibacterianos/administração & dosagem , Escherichia coli/citologia , Escherichia coli/efeitos dos fármacos , Membranas Artificiais , Nanomedicina/métodos , Nanoestruturas/administração & dosagem , Nanoestruturas/química , Cristalização/métodos , Eletroquímica/métodos , Substâncias Macromoleculares/química , Teste de Materiais , Conformação Molecular , Nanoestruturas/ultraestrutura , Tamanho da Partícula , Rotação , Propriedades de Superfície
15.
Colloids Surf B Biointerfaces ; 173: 429-436, 2019 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-30321801

RESUMO

The positionally substituted 2'-O-hydroxypropyl trimethyl ammonium chloride chitin (2'-O-HTACCT) with different substitution degree of quaternary ammonium salt were synthesized directly from ß-chitin, after that these 2'-O-HTACCT were then deacetylated to obtain corresponding 2'-O-hydroxypropyl trimethyl ammonium chloride chitosan (2'-O-HTACCS) with different deacetylation degree. The antibacterial activity and mechanism against E. coli and S. aureus of these 2'-O-HTACCT and 2'-O-HTACCS were investigated with various techniques. The results demonstrated that the 2'-O-HTACCT had antibacterial effect against S. aureus, but it had negligible antibacterial effect against E. coli, maybe due to the lack of anionic compound such as teichoic acid on the E. coli's cell wall. Impressively, the high antibacterial effect against E. coli of the 2'-O-HTACCS was derived only from its -NH2, but the ultra high antibacterial effect against S. aureus of the 2'-O-HTACCS was derived both from its -NH2 and -N+(CH3)3, and enhanced as its pH value decreased. Thus, the positionally substituted 2'-O-HTACCS played an important role as a high-performance antibacterial bio-resource polymer against E. coli and S. aureus.


Assuntos
Antibacterianos/síntese química , Parede Celular/efeitos dos fármacos , Quitina/análogos & derivados , Quitosana/análogos & derivados , Escherichia coli/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Acetilação , Antibacterianos/farmacologia , Sequência de Carboidratos , Parede Celular/química , Quitina/farmacologia , Quitosana/síntese química , Quitosana/farmacologia , Escherichia coli/química , Escherichia coli/crescimento & desenvolvimento , Concentração de Íons de Hidrogênio , Testes de Sensibilidade Microbiana , Especificidade da Espécie , Staphylococcus aureus/química , Staphylococcus aureus/crescimento & desenvolvimento , Relação Estrutura-Atividade
16.
Appl Biochem Biotechnol ; 189(2): 448-458, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31044370

RESUMO

For efficiently enhancing the activity of isoeugenol monooxygenase, a whole cell overproducing active aggregate IEM720-18A was successfully fabricated via the fusion of amphiphilic short peptide 18A (EWLKAFYEKVLEKLKELF) and isoeugenol monooxygenase and then efficiently expressed in E. coli BL21 (DE3). Such resulting bacteria, E. coli BL21 (DE3) harboring pET30a-IEM720-18A was applied in the biotransformation of isoeugenol to vanillin with the optimization of cultivation conditions. Our results revealed that the vanillin concentration reached to the highest level (14.5 mmol/L) under the optimized reaction conditions including 1.5-g cells containing active aggregate of IEM720-18A, 10% (v/v) dimethyl sulfoxide (DMSO), 100 mmol/L isoeugenol, 50 mmol/L glycine-sodium hydroxide buffer (pH 10.5) in 10 mL reaction volume, and 200 rpm at 25 °C for 36 h. Moreover, the active aggregate IEM720-18A was immobilized with 100 mmol/L glutaraldehyde at 4 °C to improve the operational stability. The highest activity could be achieved when the reactions were carried out at 25 °C and the relative activity of the immobilized enzyme maintained over 60% after seven recycles. Our study provides a new approach to the biotransformation of isoeugenol into vanillin.


Assuntos
Benzaldeídos/metabolismo , Células Imobilizadas/metabolismo , Escherichia coli/metabolismo , Eugenol/análogos & derivados , Escherichia coli/genética , Eugenol/metabolismo
17.
Mol Cell Biochem ; 319(1-2): 1-7, 2008 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18648910

RESUMO

The roles of TGF-beta and the interaction between TGF-beta and EGFR signaling are critical in Sertoli cell, though the knowledge about them is limited. RT-PCR was used to characterize the status of TGF-beta signaling in clinical testicular specimens with complete Sertoli cell-only syndrome (SCOS). The mouse Sertoli cell TM4 was used to investigate the interaction between TGF-beta and EGFR signaling by using mitogenic assay, luciferase assay, and western blot, while TM3 (mouse leydig cell), 3T3 (mouse embryo fibroblasts), and B82 (mouse lung fibroblasts) were selected as control. The RT-PCR assay indicated that the expression levels of TbetaRII and Smad2 in SCOS testes were upregulated compared to that in the normal controls. In the in vitro experiment, the TGF-beta1 downregulated cellular proliferation of TM3 and B82 cell (P < 0.05), but it did not changed the proliferation of TM4 and 3T3 cells (P > 0.05). On contrast, TGF-beta1 only increased the TGF response elements p3TP-lux activity significantly (P < 0.05) in Sertoli cell TM4. Also, the Western blot assay shows an obvious increase of Smad2 in TM4, 3T3, and TM3 cells after TGF-beta1 treatment while the EGFR expression level was significantly increased in TM4 cells only. In conclusion, the TGF-beta pathway and the cross-link between TGF-beta and EGFR signaling may play an important role on the dysfunction of Sertoli cells which induce germ stem cells' disappearance in SCOS.


Assuntos
Receptores de Fatores de Crescimento Transformadores beta/metabolismo , Síndrome de Células de Sertoli/metabolismo , Células de Sertoli/metabolismo , Transdução de Sinais , Proteína Smad2/metabolismo , Fator de Crescimento Transformador beta1/metabolismo , Células 3T3 , Adulto , Animais , Azoospermia/metabolismo , Azoospermia/patologia , Receptores ErbB/biossíntese , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Masculino , Camundongos , Síndrome de Células de Sertoli/patologia , Células de Sertoli/patologia , Fator de Crescimento Transformador beta1/farmacologia
18.
Chem Commun (Camb) ; (17): 1989-91, 2008 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-18536797

RESUMO

A general protocol based on spontaneous adsorption of cucurbit[n]uril (CB[n]) molecules through a strong multivalence interaction between CB[n] and gold is described, by which the formation of self-assembled CB[n] monolayers on gold surfaces can be efficiently achieved.

19.
Carbohydr Polym ; 148: 200-5, 2016 09 05.
Artigo em Inglês | MEDLINE | ID: mdl-27185132

RESUMO

Chitosan with different degree of deacetylation (DD) and ultra high molecular weight (MW >10(6)) was prepared from ß-chitin by mild deacetylation. The effects of DD of chitosan and pH value of its solution/suspension on its antibacterial activity were investigated. The results showed that the optimal pH value was 6.0 for the highest bactericidal activity. The antibacterial activity against Escherichia coli and Staphylococcus aureus of chitosan solution at pH 6.0 enhanced as the DD of chitosan increased. Same as chitosan with low MW, the antibacterial activity of chitosan with high MW in acidic solution was also due to the amino protonation and subsequently cationic formation. Its ultra long molecular chain was propitious to coat and bind the E. coli and S. aureus, and highly enhanced its antibacterial activity. E. coli and S. aureus were at first restrained and then killed by chitosan and the cells were ruptured and decomposed gradually.


Assuntos
Quitosana/farmacologia , Escherichia coli/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Antibacterianos/química , Antibacterianos/farmacologia , Quitosana/química , Concentração de Íons de Hidrogênio , Peso Molecular
20.
Int J Biol Macromol ; 78: 189-94, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25849997

RESUMO

The acetylsalicylic acid-acylated chitosan (ASACTS) with high degree of substitution (DS) was successfully synthesized, and characterized with FTIR, (1)H NMR and elemental analysis methods. The optimum synthesis conditions were obtained which gave the highest DS (about 60%) for ASACTS. Its drug release experiments were carried out in simulated gastric and intestine fluids. The results show that the drugs in the form of acetylsalicylic acid (ASA) and salicylic acid (SA) were released in a controlled manner from ASACTS only in simulated gastric fluid. The release profile can be best fitted with logistic and Weibull model. The research results reveal that ASACTS can be a potential polymeric drug for the controlled release of ASA and SA in the targeted gastric environment.


Assuntos
Aspirina/administração & dosagem , Quitosana/química , Preparações de Ação Retardada , Sistemas de Liberação de Medicamentos , Acetilação , Liberação Controlada de Fármacos , Espectroscopia de Prótons por Ressonância Magnética , Ácido Salicílico/administração & dosagem , Espectroscopia de Infravermelho com Transformada de Fourier
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA