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1.
Chemosphere ; 293: 133540, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-34999098

RESUMO

Pristine and Ce doped TiO2 nanoparticles were fabricated for toxic pollutants removal from wastewater. Pristine, 2% Ce and 4% Ce doped TiO2 photocatalysts were produced via hydrothermal route. 4% Ce doped TiO2 exhibited 2.41 eV bandgap which is smaller than pure TiO2. The morphology was also investigated and it was established that doping of Ce ions enhanced the surface roughness and reduced the particle size. The surface area was characterized through BET analysis and 4% Ce-TiO2 possess higher surface with large pore diameter which helped the photocatalytic activity. The prepared photocatalysts were investigated on reduction of pollutants from wastewater under visible light. Higher efficiency was obtained for 4% Ce-TiO2 photocatalyst for both model pollutants. The "k" value possessed was also higher for the doped TiO2 catalyst. These analysis reports the optimum level of ceria doping to enhance morphology, surface area and it increased activity than bare TiO2. 4% Ce-TiO2 will be the potential candidate for efficient wastewater management. The 4% Ce doped TiO2 photocatalyst provided 77% and 88% on reducing MB and RhB dyes. The dopant has developed higher surface area, morphology and good recombination rate which reduced the toxic pollutants and changed the wastewater to reuse.


Assuntos
Poluentes Ambientais , Águas Residuárias , Catálise , Titânio
2.
Chemosphere ; 291(Pt 3): 133090, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34856234

RESUMO

A facile synthesis of pristine and g-C3N4 loaded CdWO4 (Cadmium Tungstate) were reported and analyzed the effect of pollutants removal in wastewater. The samples were characterized and the morphology of the pristine sample showed the nanostructures with high cluster of layer formed. While adding PEG (Polyethylene glycol), the surface has exhibited less agglomeration and in g-C3N4 added sample the agglomeration was intensely reduced and nanostructures have been clearly found. Photocatalytic performance on cationic dye was investigated under visible light. The efficiency calculated for g-C3N4- CdWO4 sample was 85% for MB. The C/C0 plot gives better degradation. The kinetic study revealed pseudo first order reaction. The g-C3N4-CdWO4 sample exhibited higher "k" value which proved best efficiency on removing the pollutant. g-C3N4-CdWO4 sample will make better reduction on toxic pollutants and be a good candidate in futuristic applications. By carbon based derivates inclusion with photo active materials, the morphology and surface area was greatly improved and it enhances activity of host material and it will be the promising material for industrial applications.


Assuntos
Poluentes Ambientais , Nanoestruturas , Catálise , Luz , Águas Residuárias
3.
Chemosphere ; 291(Pt 1): 132677, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34715096

RESUMO

Pristine and polyethylene glycol assisted antimony tungstate (Sb2WO6) was developed via hydrothermal route. The pristine and surfactant assisted Sb2WO6 were further exemplified to reveal the properties of the samples. The bandgap calculated for Sb2WO6, 5 ml PEG- Sb2WO6, 10 ml PEG- Sb2WO6 was 2.78 eV, 2.66 eV and 2.21 eV. The 10 ml PEG assisted sample exhibited narrow bandgap. The Fourier transform infrared spectroscopy (FTIR) spectra of the samples showed metal vibrations and stretching of the water molecules adsorbed. The Raman spectra showed the vibrational modes present in Sb2WO6. The morphology was analyzed employing transmission electron microscope (TEM) for all samples. Pristine Sb2WO6 showed growth of nanorods with higher dimensions with high agglomeration. 5 ml PEG- Sb2WO6 showed the growth of nanorods with lesser agglomeration. 10 ml PEG assisted Sb2WO6 exhibited distinct growth of nanorods with no agglomeration on the surface. The elemental composition was examined employing X-ray Photoelectron Spectroscopy. Prepared product photocatalytic behaviour was tested employing Rhodamine B dye degrading. Different catalyst loading were investigated for degrading the toxic pollutants. 0.2 g 10 ml PEG-Sb2WO6 showed 81% efficiency on degrading the toxic pollutant from wastewater. The OH radicals are accountable for photocatalytic behaviour of prepared photocatalyst. The 10 ml PEG-Sb2WO6 has the good reusability behavior and stable properties after three cycles. The prepared 10 ml PEG- Sb2WO6 photocatalyst will be the potential candidate for the remediation of the water treatment.


Assuntos
Nanotubos , Purificação da Água , Catálise , Corantes , Águas Residuárias
4.
Sci Rep ; 10(1): 19198, 2020 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-33154400

RESUMO

The growth in energy devices and the role of supercapacitors are increasingly important in today's world. Designing an electrode material for supercapacitors using metals that have high performance, superior structure, are eco-friendly, inexpensive and highly abundant is essentially required for commercialization. In this point of view, quaternary chalcogenide Cu2NiSnS4 with fascinating marigold flower like microstructured electrodes are synthesized using different concentrations of citric acid (0, 0.05 M, 0.1 M and 0.2 M) by employing solvothermal method. The electrode materials physicochemical characteristics are deliberated in detail using the basic characterization techniques. The electrochemical studies revealed better electrochemical performances, in particular, Cu2NiSnS4@0.1 M-CA electrode revealed high 1029 F/g specific capacitance at 0.5 A/g current density. Further, it retained 78.65% capacity over 5000 cycles. To prove the practical applicability, a full-cell asymmetric solid-state device is fabricated, and it delivered 41.25 Wh/Kg and 750 Wh/Kg energy and power density at 0.5 A/g. The optimum citric acid added Cu2NiSnS4 electrode is shown to be a promising candidate for supercapacitor applications.

5.
J Hosp Infect ; 106(2): 295-302, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32679053

RESUMO

BACKGROUND: The effects of subinhibitory concentrations (sub-MICs) of antibacterial agents on the biofilm-forming ability of Staphylococcus aureus require further study. AIM: To investigate the effects of sub-MICs of chlorhexidine and mupirocin on biofilm formation in clinical meticillin-resistant Staphylococcus aureus (MRSA) isolates. METHODS: MRSA isolates were collected from patients with bloodstream infections at a tertiary care hospital. The basal level of biofilm formation and biofilm induction by sub-MICs of chlorhexidine and mupirocin were evaluated by measuring biofilm mass stained with Crystal Violet. FINDINGS: Of the 112 MRSA isolates tested, 63 (56.3%) and 44 (39.3%) belonged to sequence type (ST)5 and ST72 lineages, respectively, which are the predominant healthcare- and community-associated clones in South Korea. ST5 isolates were more likely to have chlorhexidine MIC ≥4 (73.0% vs 29.5%), resistance to mupirocin (23.8% vs 0%), agr dysfunction (73.0% vs 9.1%), and qacA/B gene (58.7% vs 2.3%) compared to ST72 isolates. The basal level of biofilm formation ability was frequently stronger in ST72 isolates compared to ST5 isolates (77.3% vs 12.7%). Sub-MICs of chlorhexidine and mupirocin promoted biofilm formation in 56.3% and 53.6%, respectively, of all isolates. Biofilm induction was more prevalent in ST5 isolates (85.7% for chlorhexidine, 69.8% for mupirocin) than in ST72 isolates (15.9% for chlorhexidine, 27.3% for mupirocin). CONCLUSION: Sub-MICs of chlorhexidine and mupirocin promoted biofilm formation in half of the clinical MRSA isolates. Our results suggest that ST5 MRSA biofilm can be induced together with some other bacterial virulent factors following exposure to chlorhexidine, which might confer a survival advantage to this clone in the healthcare environment.


Assuntos
Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Clorexidina/farmacologia , Desinfetantes/farmacologia , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Mupirocina/farmacologia , Portador Sadio/microbiologia , Humanos , Testes de Sensibilidade Microbiana , República da Coreia , Infecções Estafilocócicas/sangue , Infecções Estafilocócicas/microbiologia , Centros de Atenção Terciária
6.
J Nanosci Nanotechnol ; 19(7): 4033-4038, 2019 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-30764966

RESUMO

Development of sustainable synthesis of La2O3 nanocrystals formation employing Datura metel leaf extract was explored. The obtained nanocrystals were analyzed employing XRD, Raman, PL, FTIR, XPS and TEM characterizations. With increasing incubation and aging, the transformation of La(OH)3 to LaOOH and metal ellagate complex formation to La2O3 nanocrystals formation was observed. The obtained XRD results clearly revealed the transformation of lanthanum hydroxide to lanthanum oxide hydroxide and then to lanthanum oxide nanocrystals formation with 1, 4 and days. The influence of incubation and aging on La2O3 nanocrystals formation was discussed. Datura metel leaf extract product mixture over a period of incubation formed pure hexagonal lanthanum oxide nanocrystals.

7.
Orthop Traumatol Surg Res ; 103(4): 499-504, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-28359839

RESUMO

We have developed a flexible drill device that makes arthroscopic transosseous repair possible, and report preliminary results. Twelve patients with post-traumatic anterior inferior glenohumeral instability were selected. SURGICAL TECHNIQUE: the flexible drill device is inserted into the shoulder joint through the posterior portal and the guide pipe unit is placed 5mm posterior to the margin of the anterior glenoid rim. The flexible drill is driven through the glenoid with the power drill, creating a hole in the glenoid. A non-absorbable suture is passed through the hole and a sliding knot tying is performed over the capsule and labrum after completing stitches with the suture hook loaded. The same procedures are repeated in the 2, 3 and 4 o'clock positions of the glenoid. There was no recurrence of dislocation at the mean follow-up period of 52.3 months. The mean Rowe score was 89.5.


Assuntos
Artroscopia/instrumentação , Lesões de Bankart/cirurgia , Instabilidade Articular/cirurgia , Articulação do Ombro/cirurgia , Adolescente , Adulto , Artroscopia/métodos , Lesões de Bankart/diagnóstico por imagem , Feminino , Humanos , Instabilidade Articular/diagnóstico por imagem , Masculino , Amplitude de Movimento Articular , Recuperação de Função Fisiológica , Articulação do Ombro/diagnóstico por imagem , Adulto Jovem
8.
Mater Sci Eng C Mater Biol Appl ; 65: 419-24, 2016 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-27157769

RESUMO

A facile inorganic complex synthesis route has been developed to synthesis V2O5 nanostructures. The effects of varying incubation time on the crystallinity and morphology of the V2O5 phase has been investigated. The obtained XRD result clearly revealed the pure orthorhombic V2O5 crystalline phase. Raman antiphase bridging VO and chaining VO stretching modes peaks at 686 and 521cm(-1) attributed orthorhombic V2O5 characteristics. The V2p3/2 peak at the binding energies of 517eV and V2p1/2 peak at 524eV assigned to V(5+) oxidation state. Bioinspired V2O5 nanostructures as a biocompatible material for anticancer agents show excellent cytotoxicity at higher V2O5 concentration.


Assuntos
Nanoestruturas/química , Compostos de Vanádio/química , Compostos de Vanádio/toxicidade , Materiais Biocompatíveis/química , Materiais Biocompatíveis/toxicidade , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Humanos , Microscopia Eletrônica de Transmissão , Nanoestruturas/toxicidade , Nanoestruturas/ultraestrutura , Espectroscopia Fotoeletrônica
9.
Infection ; 43(2): 207-9, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25623639

RESUMO

Nontuberculous mycobacteria (NTM) joint involvement is rare. However, the incidence of NTM disease is increasing and it is difficult to distinguish NTM from Mycobacterium tuberculosis (MTB). Here, the clinical characteristics of NTM joint involvement were compared with those of MTB. Distal joint involvement and precipitating factors were significantly more frequent for NTM joint infections. Because pathologic findings of NTM and MTB were similar, microbiological investigations are needed.


Assuntos
Artropatias/diagnóstico , Artropatias/microbiologia , Mycobacterium tuberculosis , Micobactérias não Tuberculosas , Tuberculose Osteoarticular/diagnóstico , Tuberculose Osteoarticular/microbiologia , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
10.
Mater Sci Eng C Mater Biol Appl ; 41: 17-27, 2014 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-24907732

RESUMO

In the present investigation, we report a sustainable novel green synthetic strategy to synthesis zinc oxide nanocrystals. This is the first report on sustainable biosynthesis of zinc oxide nanocrystals employing Nephelium lappaceum L., peel extract as a natural ligation agent. Green synthesis of zinc oxide nanocrystals was carried out via zinc-ellagate complex formation using rambutan peel wastes. The successful formation of zinc oxide nanocrystals was confirmed employing standard characterisation studies. A possible mechanism for the formation of ZnO nanocrystals with rambutan peel extract was also proposed. The prepared ZnO nanocrystals were coated on the cotton fabric and their antibacterial activity were analyzed. ZnO nanocrystals coated cotton showed good antibacterial activity towards Escherichia coli (E. coli), gram negative bacteria and Staphylococcus aureus (S. aureus), gram positive bacteria.


Assuntos
Antibacterianos/síntese química , Nanopartículas Metálicas/química , Extratos Vegetais/química , Sapindaceae/química , Óxido de Zinco/química , Antibacterianos/química , Antibacterianos/farmacologia , Escherichia coli/efeitos dos fármacos , Frutas/química , Frutas/metabolismo , Química Verde , Testes de Sensibilidade Microbiana , Microscopia de Força Atômica , Sapindaceae/metabolismo , Staphylococcus aureus/efeitos dos fármacos
11.
Cell Death Dis ; 3: e319, 2012 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-22673193

RESUMO

Twist1 is highly expressed in primary and metastatic non-small cell lung cancer (NSCLC), and thus acts as a critical target for lung cancer chemotherapy. In the current study, we investigated the underlying mechanism initiated by silencing of Twist1 that sensitizes NSCLC cells to cisplatin. Silencing of Twist1 triggered ATP depletion, leading to AMP-activated protein kinase (AMPK)-activated mammalian target of rapamycin (mTOR) inhibition in NSCLC cells. AMPK-induced mTOR inhibition, in turn, resulted in downregulation of ribosome protein S6 kinase 1 (S6K1) activity. Downregulation of mTOR/S6K1 reduced Mcl-1 protein expression, consequently promoting sensitization to cisplatin. Overexpression of Mcl-1 reduced PARP cleavage induced by cisplatin and Twist1 siRNA, suggesting that this sensitization is controlled through Mcl-1 expression. Interestingly, cells treated with Twist1 siRNA displayed upregulation of p21(Waf1/CIP1), and suppression of p21(Waf1/CIP1) with specific siRNA further enhanced the cell death response to cisplatin/Twist1 siRNA. In conclusion, silencing of Twist1 sensitizes lung cancer cells to cisplatin via stimulating AMPK-induced mTOR inhibition, leading to a reduction in Mcl-1 protein. To our knowledge, this is the first report to provide a rationale for the implication of cross-linking between Twist1 and mTOR signaling in resistance of NSCLC to anticancer drugs.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Antineoplásicos/farmacologia , Carcinoma Pulmonar de Células não Pequenas/patologia , Cisplatino/farmacologia , Inativação Gênica , Neoplasias Pulmonares/patologia , Proteínas Nucleares/genética , Serina-Treonina Quinases TOR/antagonistas & inibidores , Proteína 1 Relacionada a Twist/genética , Apoptose , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Linhagem Celular Tumoral , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Proteínas Nucleares/metabolismo , Transdução de Sinais , Serina-Treonina Quinases TOR/metabolismo , Proteína 1 Relacionada a Twist/metabolismo
12.
Oncogene ; 30(35): 3792-801, 2011 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-21460850

RESUMO

The mammalian target of rapamycin (mTOR) is a highly conserved serine-threonine kinase activated in response to growth factors and nutrients. Because of frequent dysregulation of the mTOR signaling pathway in diverse human cancers, this kinase is a key therapeutic target. Redd1 is a negative regulator of mTOR, mediating dissociation of 14-3-3 from tuberous sclerosis complex (TSC)2, which allows formation of a TSC-TSC2 complex. In the present study, we identify TXNIP that inhibits mTOR activity by binding to and stabilizing Redd1 protein. Redd1 and TXNIP expression was induced by a synthetic glucose analog, 2-deoxyglucose (2-DG). Moreover, Redd1 expression in response to 2-DG was regulated by activating transcription factor 4 (ATF4). Overexpression of TXNIP was associated with reduced mTOR activity mediated by an increase in Redd1 level, whereas knockdown of TXNIP using small interfering RNA resulted in recovery of mTOR activity via downregulation of Redd1 during treatment with 2-DG. Interestingly, Redd1 was additionally stabilized via interactions with N-terminal-truncated TXNIP, leading to suppression of mTOR activity. Our results collectively demonstrate that TXNIP stabilizes Redd1 protein induced by ATF4 in response to 2-DG, resulting in potentiation of mTOR suppression. To the best of our knowledge, this is the first study to identify TXNIP as a novel member of the mTOR upstream that acts as a negative regulator in response to stress signals.


Assuntos
Proteínas de Transporte/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Fatores de Transcrição/metabolismo , Fator 4 Ativador da Transcrição/metabolismo , Linhagem Celular Tumoral , Desoxiglucose/farmacologia , Humanos , Estabilidade Proteica , Serina-Treonina Quinases TOR/antagonistas & inibidores
13.
Soc Sci Med ; 71(2): 414-420, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20510493

RESUMO

Experience Corps (EC) is a high-commitment US volunteer program that brings older adults into public elementary schools to improve academic achievement of students. It is viewed as a health promotion program for the older volunteers. We evaluated the effects of the EC program on older adults' health, using a quasi-experimental design. We included volunteers from 17 EC sites across the US. They were pre-tested before beginning their volunteer work and post-tested after two years of service. We compared changes over time between the EC participants (n = 167) and a matched comparison group of people from the US Health and Retirement Study (2004, 2006). We developed the comparison group by using the nearest available Mahalanobis metric matching within calipers combined with the boosted propensity scores of those participating in the EC. We corrected for clustering effects via survey regression analyses with robust standard errors and calculated adjusted post-test means of health outcomes, controlling for all covariates and the boosted propensity score of EC participants. We found that compared to the comparison group, the EC group reported fewer depressive symptoms and functional limitations after two years of participation in the program, and there was a statistical trend toward the EC group reporting less decline in self-rated health. Results of this study add to the evidence supporting high-intensity volunteering as a social model of health promotion for older adults.


Assuntos
Nível de Saúde , Voluntários , Atividades Cotidianas , Idoso , Idoso de 80 Anos ou mais , Depressão/prevenção & controle , Feminino , Promoção da Saúde , Humanos , Masculino , Pessoa de Meia-Idade , Avaliação de Programas e Projetos de Saúde , Análise de Regressão , Autoimagem , Voluntários/psicologia
14.
Oncogene ; 29(4): 561-75, 2010 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-19855432

RESUMO

Premature senescence is considered as a cellular defense mechanism to prevent tumorigenesis. Although recent evidences show that c-Jun N-terminal kinase (JNK) is involved in the senescence process, the mechanism for this regulation is not fully understood. Here, we examined the role of JNK in premature senescence of tumor cells. Treatment of cells with the JNK-specific inhibitor SP600125 caused phenotypical changes of senescence and triggered a rapid increase in mitochondrial reactive oxygen species (ROS) production and DNA-damage response (DDR) in MCF7 breast carcinoma cells. ROS generation was attributed to the suppression of B-cell lymphoma-2 (Bcl-2) phosphorylation, and resulted in DNA damage and p53 activation. Bax did not change their localization to the mitochondria, which is required for apoptosis. The essential roles of JNK and phosphorylated Bcl-2 in preventing premature senescence were confirmed using RNA interference and ectopic expression of mutants of Bcl-2, including phosphomimetic and nonphosphorylatable forms. These findings were evidenced in H460 lung carcinoma cells and primary human embryonic fibroblasts. Altogether, our results showed that loss of JNK activity triggers a Bcl-2/ROS/DDR signaling cascade that ultimately leads to premature senescence, indicating that basal JNK activity is essential in preventing premature senescence.


Assuntos
Diferenciação Celular , Senescência Celular , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Antracenos/farmacologia , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Senescência Celular/efeitos dos fármacos , Dano ao DNA , Humanos , Proteínas Quinases JNK Ativadas por Mitógeno/antagonistas & inibidores , Proteínas Quinases JNK Ativadas por Mitógeno/genética , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas c-bcl-2/genética , RNA Interferente Pequeno/genética
15.
J Mater Sci Mater Med ; 20(4): 959-65, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19034616

RESUMO

The ultrastructure of murine femoral lamellar bone and the effect of electron irradiation (200 kV) on collagen and mineral features were investigated using in situ high resolution transmission electron microscopy (HRTEM). Bands of collagen fibrils were mostly aligned parallel to the long axis of the bones, with some bands of fibrils inclined in longitudinal sections. The similarity of the ultrastructure between the longitudinal and transverse sections supports the rotated plywood structure of the lamellar bone. The collagen fibrils appeared damaged and the mineral crystals were coarsened after electron irradiation. Continuous diffraction rings became spotty and the contrast between rings and the background became sharper, further suggesting coarsening of apatite crystals and increased crystallinity after irradiation. No new phases were observed after irradiation. Both the damage to collagen and coarsening of apatite crystals can deteriorate the strength and integrity of bone, and may provide insight into fracture in patients who have undergone radiation therapy.


Assuntos
Osso e Ossos/efeitos da radiação , Animais , Osso e Ossos/ultraestrutura , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microscopia Eletrônica de Transmissão
16.
J Mater Res ; 23(2): 478-485, 2008 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-19763228

RESUMO

The ultrastructure of nanoscale apatite biomimetically formed on an organic template from a supersaturated mineralizing solution was studied to examine the morphological and crystalline arrangement of mineral apatites. Needle-shaped apatite crystal plates with a size distribution of ~100 to ~1000 nm and the long axis parallel to the c axis ([002]) were randomly distributed in the mineral films. Between these randomly distributed needle-shaped apatite crystals, amorphous phases and apatite crystals (~20-40 nm) with the normal of the grains quasi-perpendicular to the c axis were observed. These observations suggest that the apatite film is an interwoven structure of amorphous phases and apatite crystals with various orientations. The mechanisms underlying the shape of the crystalline apatite plate and aggregated apatite nodules are discussed from an energy-barrier point of view. The plate or needle-shaped apatite is favored in single-crystalline form, whereas the granular nodules are favored in the polycrystalline apatite aggregate. The similarity in shape in both single-crystalline needle-shaped apatite and polycrystalline granular apatite over a wide range of sizes is explained by the principle of similitude, in which the growth and shape are determined by the forces acting upon the surface area and the volume.

17.
Bioresour Technol ; 98(1): 191-7, 2007 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16458001

RESUMO

The production of penicillic acid by Aspergillus sclerotiorum CGF for the biocontrol of Phytophthora disease was investigated in submerged fermentation using media composed of different nutrients. Soluble starch was found to be the most effective substrate among the carbon sources used, and produced the highest penicillic acid concentration of 2.98 mg ml(-1). When organic nitrogen sources were used, pharmamedia, yeast extract, and polypeptone-S were found to be suitable organic nitrogen sources (2.46-2.71 mg ml(-1)). The production of penicillic acid was not detected in when inorganic nitrogen sources were used. Only Na2HPO4, among the metal ions and phosphate salts tested, increased the production of penicillic acid (approximately 20%). When A. sclerotiorum CGF was cultured in optimal medium [8.0% (w/v) soluble starch, 0.6% (w/v) yeast extract, and 0.3% (w/v) Na2HPO4], maximum penicillic acid concentration (approximately 9.40 mg ml(-1)) and cell mass (approximately 17.4 g l(-1)) were obtained after 12 days.


Assuntos
Aspergillus/metabolismo , Ácido Penicílico/metabolismo , Carbono/metabolismo , Fermentação , Concentração de Íons de Hidrogênio , Metais/metabolismo , Nitrogênio/metabolismo , Phytophthora/efeitos dos fármacos , Amido/metabolismo , Fatores de Tempo
18.
J Mater Sci Mater Med ; 18(5): 925-31, 2007 May.
Artigo em Inglês | MEDLINE | ID: mdl-17143738

RESUMO

In this study, a newly developed duplex coating method incorporating plasma carburization and CrN coating was applied to Ti-6Al-4V and its effects on the wear resistance and fatigue life were investigated. The carburized layer with approximately150 microm in depth and CrN coating film with 7.5 microm in thickness were formed after duplex coating. Hard carbide particles such as TiC And V(4)C(3) were formed in the carburized layer. XRD diffraction pattern analysis revealed that CrN film had predominant [111] and [200] textures. The hardness (Hv) was significantly improved up to about 1,960 after duplex coating while the hardness value of original Ti-6Al-4V was 402. The threshold load for the modification and/or failure of CrN coating was measured to be 32 N using the acoustic emission technique. The wear resistance and fatigue life of duplex-coated Ti-6Al-4V improved significantly compared to those of un-treated specimen. The enhanced wear resistance can be attributed to the excellent adhesion and improved hardness of CrN coating film for the duplex-coated Ti-6Al-4V. The initiation of fatigue cracks is likely to be retarded by the presence of hard and strong layers on the surface, resulting in the enhanced fatigue life.


Assuntos
Compostos de Cromo/química , Materiais Revestidos Biocompatíveis/química , Titânio/química , Ligas/química , Fenômenos Biomecânicos , Temperatura Alta , Teste de Materiais , Microscopia Eletrônica de Varredura , Propriedades de Superfície , Difração de Raios X
19.
Bioresour Technol ; 91(2): 153-6, 2004 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-14592744

RESUMO

To investigate the production of cellulases and hemicellulases from Aspergillus niger KK2, solid state fermentation (SSF) was performed by using different ratios of rice straw and wheat bran. When A. niger KK2 was grown on rice straw alone as a solid support in SSF, the maximum FPase activity was 19.5 IU g(-1) in 4 days. Also, CMCase (129 IU g(-1)), beta-glucosidase (100 IU g(-1)), xylanase (5070 IU g(-1)) and beta-xylosidase (193 IU g(-1)) activities were concurrently obtained after 5-6 days of fermentation. The higher enzyme activities produced by A. niger KK2 is a significant advantage from the viewpoint of practical saccharification reaction. Cellulases and hemicellulases produced by A. niger KK2 might be applied to pulp and paper industry, feed industry and chemical industry.


Assuntos
Aspergillus niger/enzimologia , Celulases/biossíntese , Celulose/metabolismo , Glicosídeo Hidrolases/biossíntese , Lignina/metabolismo , Fibras na Dieta , Fermentação , Cinética , Oryza
20.
Appl Biochem Biotechnol ; 111(2): 65-80, 2003 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-14645999

RESUMO

As a novel feeding strategy for optimizing human epidermal growth factor (hEGF) production with a recombinant Hansenula polymorpha DL-1 using the methanol oxidase (MOX) promoter in H. polymorpha DL-1, independent exponential feeding of two substrates was used. A simple kinetic model considering the cell growth on two substrates was established and used to calculate the respective feeding rates of glycerol and methanol. In the fedbatch culture with methanol-only feeding, the optimal set point of specific growth rate on methanol was found to be 0.10 h-1. When the fed-batch cultures were conducted by the independent feeding of glycerol and methanol, the actual specific growth rate on glycerol and methanol was slightly lower than the set point of specific growth rate. By the uncoupled feeding of glycerol and methanol the volumetric productivity of hEGF increased from 6.4 to 8.0 mg/(L.h), compared with methanol-only feeding.


Assuntos
Oxirredutases do Álcool/genética , Fator de Crescimento Epidérmico/biossíntese , Glicerol/metabolismo , Metanol/metabolismo , Pichia/crescimento & desenvolvimento , Pichia/genética , Reatores Biológicos , Meios de Cultura , Fator de Crescimento Epidérmico/genética , Fermentação , Humanos , Pichia/enzimologia , Pichia/metabolismo , Regiões Promotoras Genéticas , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/genética , Transformação Genética
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