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1.
Cureus ; 16(2): e54367, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38500930

RESUMO

BACKGROUND: Temporomandibular joint (TMJ) pain is a common condition that can significantly impact an individual's quality of life. Current treatment options often fall short of providing long-lasting relief. So, this prospective clinical study aimed to investigate the efficacy of injectable platelet-rich fibrin (I-PRF) in mitigating TMJ pain. METHODS: A total of 68 participants, aged 18-60 years, clinically diagnosed with TMJ pain, were recruited from dental clinics and specialist referrals. Participants were randomly assigned to either the intervention group (I-PRF injections) or the control group (placebo). Primary outcome measures included TMJ pain intensity and jaw function, assessed using the Visual Analog Scale and functional examinations, respectively. Secondary outcomes comprised patient-reported outcomes (PROs) on quality of life and satisfaction. Data were collected at baseline and six, 12, and 24 weeks post intervention. RESULTS: Baseline characteristics demonstrated successful randomization, with no significant differences in age, gender, or TMJ pain duration between groups. Post intervention, the intervention group exhibited a significant and sustained reduction in TMJ pain intensity compared to controls (p<0.001). Improvements in jaw function were also notable in the intervention group at all follow-up time points (p<0.001). PROs related to quality of life and satisfaction substantially increased in the intervention group compared to controls (p<0.001). CONCLUSION: I-PRF demonstrated significant efficacy in reducing TMJ pain intensity, improving jaw function, and enhancing PROs. These findings support the consideration of I-PRF as a valuable therapeutic intervention for individuals with TMJ pain.

2.
J Indian Assoc Pediatr Surg ; 28(1): 25-28, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36910297

RESUMO

Purpose: Midgut volvulus is a surgical emergency requiring immediate intervention. Intestinal ischemia of the midgut as a consequence of volvulus from malrotation is a fateful event with high mortality and significant morbidity even in survivors. Derotation followed by correction of malrotation is the procedure of choice though has significant morbidity if intestinal reperfusion was not successful. A combined treatment to restore intestinal perfusion based on the digital massage of the superior mesenteric artery after derotation and systemic infusion of fibrinolytic has been previously reported with success but underused. Here, we report three such cases of midgut malrotation with severe intestinal ischemia due to volvulus. Materials and Methods: A retrospective analysis of three confirmed cases of midgut malrotation with volvulus managed with emergency laparotomy, derotation, and Superior Mesenteric Artery (SMA) massage with systemic fibrinolytic therapy, followed by correction of malrotation was evaluated. Results: There was dramatic improvement in intestinal perfusion noted in all three patients inspite of delayed presentation. 2 out of 3 patients on follow up are doing well with adequate weight gain while 1 patient succumbed due to sepsis. Conclusion: Critical intestinal ischemia due to mesenteric thrombosis can persist after derotation of midgut volvulus and can lead to devastating consequences. The use of digital massage of SMA to disrupt the thrombus along with fibrinolytic therapy though reported is underutilized. Hence, awareness of this management and usage needs to be re-emphasized.

3.
J Mater Sci Mater Med ; 27(2): 27, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26704544

RESUMO

Tissue culture under microgravity provides a venue which promotes cell-cell association while avoiding the detrimental effects of high shear stress. Hepatocytes cultured on carriers or entrapped within matrices under simulated microgravity conditions showed improved cell function and proliferation. In the present study, a new approach was adopted where a non-cell adherent scaffold was incorporated with hepatospheroids (HepG2) under microgravity. Gum arabic (GA) was cross-linked with gelatin (GA-Gel) and collagen (GA-Col) to prepare non-cell adherent scaffolds. Microgravity experiments with GA-Gel and GA-Col indicated that GA-Col is a better substrate compared to GA-Gel. Microgravity experiments of GA-Col scaffolds with HepG2 cells confirmed that the non-adherent surface with porous architecture can incorporate hepatocyte spheroids and maintain liver specific functions. Albumin and urea synthesis of hepatocytes was sustained up to 6 days under microgravity conditions in the presence of GA-Col scaffold. This new approach of using non-cell adherent matrix and microgravity environment for developing biological substitutes will be beneficial in tissue engineering, bioartificial liver devices and in vitro safety assessment of drugs.


Assuntos
Extratos Celulares/química , Fígado Artificial , Fígado/química , Polissacarídeos/química , Agregados Proteicos , Alicerces Teciduais/química , Ausência de Peso , Técnicas de Cultura de Células/métodos , Células Hep G2 , Hepatócitos/citologia , Humanos , Fígado/citologia , Agregados Proteicos/fisiologia , Esferoides Celulares/citologia , Engenharia Tecidual/instrumentação , Engenharia Tecidual/métodos
4.
Mater Sci Eng C Mater Biol Appl ; 43: 272-9, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25175214

RESUMO

The present work deals with development of modified gum arabic cross-linked gelatin scaffold for cell culture. A new biocompatible scaffold was developed by cross-linking gelatin (Gel) with gum arabic, a polysaccharide. Gum arabic was subjected to periodate oxidation to obtain gum arabic aldehyde (GAA). GAA was reacted with gelatin under appropriate pH to prepare the cross-linked hydrogel. Cross-linking occurred due to Schiff's base reaction between aldehyde groups of oxidized gum arabic and amino groups of gelatin. The scaffold prepared from the hydrogel was characterized by swelling properties, degree of cross-linking, in vitro degradation and scanning electron microscopy (SEM). Cytocompatibility evaluation using L-929 and HepG2 cells confirmed non-cytotoxic and non-adherent nature of the scaffold. These properties are essential for generating multicellular spheroids and hence the scaffold is proposed to be a suitable candidate for spheroid cell culture.


Assuntos
Gelatina/química , Goma Arábica/química , Alicerces Teciduais , Animais , Linhagem Celular , Linhagem Celular Tumoral , Humanos , Concentração de Íons de Hidrogênio , Camundongos , Microscopia Eletrônica de Varredura , Oxirredução , Viscosidade
5.
Ann Am Thorac Soc ; 11(6): 859-64, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24950156

RESUMO

RATIONALE: It is not known how the 2011 Global Initiative for Chronic Obstructive Lung Disease (GOLD) strategy predicts clinical course of α1-antitrypsin deficiency (AATD). OBJECTIVES: To determine how the new strategy relates to outcomes (i.e., mortality, lung function decline, and exacerbations) in patients with AATD. METHODS: All PiZZ patients (patients with ZZ genotype causing severe AATD) on the AATD registry with a physiological diagnosis of chronic obstructive pulmonary disease were grouped into four GOLD categories (A, B, C, and D) on the basis of their combined risk. We then compared mortality and lung function decline in these categories and also assessed the predictive ability of exacerbation history in the patients. MEASUREMENTS AND MAIN RESULTS: Mortality (GOLD categories A: 6 [5.8%]; B: 7 [5.93%]; C: 11 [9.32%]; D: 94 [79.66%]) was greatest in high-symptom, high-risk category D (P = 0.0001), which also showed a faster decline in Kco (mmol/min/kPa/L/yr, mean [SD], A: -0.021 [0.03]; B: -0.022 [0.03]; C: -0.032 [0.03]; D: -0.031 [0.03]) (P = 0.012). The fastest mean decline in FEV1 (ml/yr, mean [SD], A: -66.59 [61.39]; B: -53.00 [47.09]; C: -56.96 [48.87]; D: -41.25 [62.09]) was observed in category A and least in category D (P = 0.002). Multivariate analysis showed that GOLD category was significant for all outcomes (P < 0.05). CONCLUSIONS: The new strategy performs well in identifying patients with increased risk of poorer outcomes in AATD. This has therapeutic implications enabling more aggressive therapy to be directed to those in the highest-risk group. Further studies to identify subgroups of patients most likely to benefit from augmentation therapy are indicated.


Assuntos
Pulmão/fisiopatologia , Guias de Prática Clínica como Assunto , Doença Pulmonar Obstrutiva Crônica/terapia , Deficiência de alfa 1-Antitripsina/terapia , Feminino , Seguimentos , Volume Expiratório Forçado , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Modelos de Riscos Proporcionais , Doença Pulmonar Obstrutiva Crônica/complicações , Doença Pulmonar Obstrutiva Crônica/mortalidade , Recidiva , Estudos Retrospectivos , Taxa de Sobrevida/tendências , Fatores de Tempo , Reino Unido/epidemiologia , Deficiência de alfa 1-Antitripsina/complicações , Deficiência de alfa 1-Antitripsina/mortalidade
6.
Chest ; 144(4): 1152-1162, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23787410

RESUMO

BACKGROUND: The new GOLD (Global Initiative for Chronic Obstructive Lung Disease) strategy recommends use of the COPD Assessment Test (CAT) or modified Medical Research Council (mMRC) scale to assess symptoms in COPD against "risk" as assessed by spirometry or exacerbation frequency. We aimed to determine the concordance between CAT and mMRC scale in assessing risk in patients with α1-antitrypsin deficiency (AATD) and the CAT threshold for risk assessment at which similar proportions of patients are assigned into the risk categories. METHODS: Distribution of 309 patients (protease inhibitor Z phenotype) in four GOLD categories (A, B, C, and D) was compared. Using CAT for symptoms, we compared patient distribution using scores between 10 and 15 to ascertain the CAT threshold at which the distribution of patients in each group is proportional. RESULTS: Using CAT 10 and spirometry for risk assessment, 6.1% of patients were in group A (low symptoms/low risk), 39.2% in B (high symptoms/low risk), 2.3% in C (low symptoms/high risk), and 52.4% in D (high symptoms/high risk). Using mMRC scale and spirometry for risk produced a significantly different distribution from that using CAT (P < .0001). Using CAT 13 as a symptom threshold and spirometry for risk resulted in a more proportional distribution of patients, which was similar using CAT and exacerbation history (P > .0001) and mMRC scale and spirometry and/or exacerbation history for risk (P > .0001). CONCLUSIONS: In patients with AATD, using either the mMRC scale 0 to 1 or CAT 10 scores to determine symptoms results in a significant difference in patient distribution. However, CAT 13 as the threshold for assessing symptoms results in a similar proportion of patients being categorized into the risk categories.


Assuntos
Doença Pulmonar Obstrutiva Crônica/complicações , Doença Pulmonar Obstrutiva Crônica/diagnóstico , Deficiência de alfa 1-Antitripsina/complicações , Algoritmos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Medição de Risco , Avaliação de Sintomas
7.
Artigo em Inglês | MEDLINE | ID: mdl-22995472

RESUMO

Under UV-A light illumination, formation of iodine from iodide ion on the surfaces of anatase TiO(2), ZnO, Fe(2)O(3), CeO(2), MoO(3), Bi(2)O(3), and Nb(2)O(5) increases with the concentration of iodide ion, airflow rate and light intensity and conform to the Langmuir-Hinshelwood kinetic model. Measurement of the particle size of the semiconductor oxides by light scattering method and deduction of the same from the determined specific surface area show that the oxide particles agglomerate in suspension. However, mixtures of any two listed particulate semiconductors do not show enhanced photocatalytic formation of iodine indicating absence of interparticle charge transfer. The results are rationalized.


Assuntos
Iodetos/química , Iodo/química , Óxidos/química , Semicondutores , Catálise , Tamanho da Partícula , Raios Ultravioleta
8.
Indian J Tuberc ; 59(1): 28-31, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22670508

RESUMO

BACKGROUND: Knowledge of the position and grade of accessory fissures and lobes is necessary for appreciation of lobar anatomy and thus locating bronchopulmonary segments. METHODS: Morphological variations of accessory fissures and lobes of the lungs were studied in 40 pairs of lungs from cadavers. RESULTS: Four left-sided lungs and two right-sided lungs showed accessory fissure in the lower lobe. Only one accessory fissure of left lung belongs to grade-ii and the remaining belongs to grade iii. [According to Craig and Walker's fissural classification] CONCLUSIONS: Awareness regarding accessory fissures and lobes is essential for performing lobectomies, segmental resection, for differential diagnosis and interpreting radiological images.


Assuntos
Pulmão/anatomia & histologia , Cadáver , Dissecação , Humanos , Índia , Pulmão/anormalidades
9.
Curr Med Chem ; 18(14): 2045-59, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21517770

RESUMO

Fullerenes as a unique class of carbon allotropes have been studied extensively for their distinctive material properties and potential technological applications, including those in biology and medicine. Since a major focus in the latter has been on drug development and formulation, in this paper we highlight some representative studies related to such a focus, including the use of fullerenes for drug-like functions and for their improving the formulation of established drugs. Also discussed are some other potential medically relevant applications of fullerenes, such as their serving as potent agents in photodynamic therapy and magnetic imaging.


Assuntos
Fulerenos/uso terapêutico , Imageamento por Ressonância Magnética/métodos , Nanomedicina/métodos , Animais , Fármacos Anti-HIV/química , Fármacos Anti-HIV/uso terapêutico , Meios de Contraste , Portadores de Fármacos/química , Sequestradores de Radicais Livres/química , Sequestradores de Radicais Livres/uso terapêutico , Fulerenos/química , HIV/efeitos dos fármacos , Infecções por HIV/tratamento farmacológico , Humanos , Melanoma/tratamento farmacológico , Modelos Moleculares , Nanoestruturas/uso terapêutico , Fotoquimioterapia/métodos , Fármacos Fotossensibilizantes/química , Fármacos Fotossensibilizantes/uso terapêutico
10.
Rev Recent Clin Trials ; 6(2): 114-26, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21241232

RESUMO

Osteoarthritis (OA) is a chronic arthritis affecting growing numbers of the ageing population. Patients diagnosed with OA place a large burden on access to healthcare services, including primary care, prescription of analgesic drugs, physiotherapy and joint replacement surgery. Not all patients diagnosed with OA will require joint replacement surgery, and therefore avenues for non-surgical treatment for such patients need to be explored in many cases. In this review we discuss current concepts underlying the pathophysiology of OA. These form a basis to understanding the rationale for new and existing therapies based on recent evidence available from clinical studies and trials in OA. In particular, we discuss the evidence for use of pharmacological treatments, including NSAIDs (non-steroidal anti-inflammatory drugs), chondroitin sulphate and glucosamine, hyaluronan, potential disease-modifying drugs and other interventions such as weight reduction and physiotherapy. Finally, we discuss new developments from clinical evidence for surgical options, including ACL repair surgery and joint replacement surgery.


Assuntos
Osteoartrite/terapia , Anti-Inflamatórios , Artroplastia , Humanos , Osteoartrite/diagnóstico , Osteoartrite/etiologia
11.
J Environ Manage ; 91(11): 2172-85, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-20576347

RESUMO

The need for ICZM arises often due to inadequate or inappropriate landuse planning practices and policies, especially in urban coastal zones which are more complex due to the larger number of components, their critical dimensions, attributes and interactions. A survey of literature shows that there is no holistic metric for assessing the impacts of landuse planning on the health of a coastal zone. Thus there is a need to define such a metric. The proposed metric, CHI (Coastal zone Health Indicator), developed on the basis of coastal system sustainability, attempts to gauge the health status of any coastal zone. It is formulated and modeled through an expert survey and pertains to the characteristic components of coastal zones, their critical dimensions, and relevant attributes. The proposed metric is applied to two urban coastal zones and validated. It can be used for more coast friendly and sustainable landuse planning/masterplan preparation and thereby for the better management of landuse impacts on coastal zones.


Assuntos
Conservação dos Recursos Naturais/métodos , Ecossistema , Monitoramento Ambiental/métodos , Política Ambiental , Modelos Teóricos , Cidades , Atividades Humanas , Oceanos e Mares
12.
J Phys Chem B ; 114(2): 728-36, 2010 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-19924837

RESUMO

We report a unique supramolecular organogel template approach for conducting polyaniline nanomaterials. A novel organogel based on sulfonic acid dopant was designed and developed from renewable resource 3-pentadecyl phenol via ring-opening of 1,4-butane sultone. The amphiphilic dopant molecule formed thermo-reversible supramolecular organogel in highly polar solvents like alcohols. The self-assembled fibril network morphology of the gel was confirmed by scanning electron microscopy (SEM) and atomic force microscopy. Transmission electron microscopy (TEM) revealed that the inner part of the fibrous gel is nanotubular with the pore diameter of approximately 75 nm. The organogel nanotubular morphology was retained even in the presence of aniline+dopant complex, and the aniline monomers occupied the hydrophobic nanopockets provided by the amphiphilic dopant. The chemical oxidative polymerization of the dopant+aniline organogel template produced well-defined polyaniline nanofibers. The polymerization was carried out at various temperatures to establish the role of the physical state and stability of the organogel on the morphology. The sulfonic acid molecule acts both as self-assembled molecular template for the synthesis of polymer nanomaterial as well as anionic counterpart for stabilizing the positively charged conducting polymer chains. The gel template played a pivotal role in directing polyaniline chains to form nanofibers and also manipulating the number of other properties such as conductivity, solubility, percent crystallinity, and solid-state ordering, etc. Temperature-dependent electrical conductivity measurements revealed that the nanomaterials showed typical linear ohmic behavior and also followed the 3-D VRH model at elevated temperatures.

13.
J Phys Chem B ; 113(34): 11614-24, 2009 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-19642663

RESUMO

We report a soft template approach based on a custom-designed novel surfactant-cum-dopant for size and shape tuning of polyaniline nanomaterials such as nanofibers and nanotapes via emulsion and dispersion polymerization routes. A new amphiphilic 4-(3-dodecyl-8-enylphenyloxy) butane sulfonic acid was synthesized by ring-opening of butanesultone with renewable resource cardanol. The new amphiphilic dopant forms spherical micelles in water and its critical micelle concentration was determined by dye encapsulation and surface tension methods. In the emulsion route, the amphiphilic dopant complexed with aniline to produce cylindrical micellar aggregates that template exclusively for polyaniline nanofibers. The dispersion of aniline+dopant in water/toluene solvent mixture produces vesicles that selectively template for polyaniline nanotapes. The mechanism of the polyaniline nanomaterials formation was investigated by dynamic light scattering (DLS) and high-resolution transmission electron microscopy (HR-TEM). DLS of the polymerization templates in water proved the presence of micrometer range aggregates, and TEM images confirmed the shape of the cylindrical and vesicular templates. The polyaniline nanomaterials were found soluble in water and polar organic solvents for structural characterization and composition analysis by 1H NMR spectroscopy. Absorbance spectra of the nanomaterials showed free carrier tail above 900 nm in the near IR region for the delocalization of electrons in the polaron band corresponding to expanded conformation of polyaniline chains. Wide angle X-ray diffraction showed two new peaks at low angle region with d-spacing of 26.5 and 13.6 A corresponding to lamellar ordering of polyaniline chains followed by interdigitations of the amphiphilic dopant in the nanomaterials.


Assuntos
Ácidos Alcanossulfônicos/química , Compostos de Anilina/química , Nanofibras/química , Tensoativos/química , Ácidos Alcanossulfônicos/síntese química , Emulsões , Micelas , Tamanho da Partícula , Propriedades de Superfície , Tensoativos/síntese química , Tolueno/química , Água/química
14.
J Hazard Mater ; 167(1-3): 664-8, 2009 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-19200656

RESUMO

Under UV light, phenol degrades on the surface of Y(2)O(3), an insulator, and the degradation follows first-order kinetics, depends linearly on the light intensity and slows down with pH. The efficiency of degradation is higher with UV-C light than with UV-A light. While particulate anatase TiO(2), ZnO, ZnS, Fe(2)O(3), CuO, CdO, and Nb(2)O(5) individually photodegrade phenol, each semiconductor shows synergism when present along with Y(2)O(3), indicating electron-transfer from phenol adsorbed on Y(2)O(3) to the illuminated semiconductors.


Assuntos
Poluentes Ambientais/química , Fenóis/química , Fotólise , Ítrio/química , Poluentes Ambientais/efeitos da radiação , Cinética , Fenóis/efeitos da radiação , Semicondutores , Raios Ultravioleta
15.
Langmuir ; 24(17): 9754-62, 2008 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-18680331

RESUMO

Here, we report a synthesis of novel polyaniline nanospheres bearing mono- and bishydroxyl functional groups to trace the molecular interactions at the nanosurfaces through vitamin C sensing. Two new aniline monomers were synthesized via a tailor-made approach and polymerized to produce soluble and uniform polyaniline nanospheres. The structures of the monomers and polymers were characterized by NMR, FT-IR, and MS techniques, and the morphology of the nanomaterials was analyzed by SEM and TEM. The mechanistic aspects of the nanomaterial formations were analyzed by FT-IR and dynamic light scattering techniques. These studies revealed that the hydroxyl-functionalized monomers have strong hydrogen bonding at the monomer level and form spherical aggregates in water, which are templates for the polyaniline nanospheres 600 +/- 100 nm in size. A controlled synthesis was also carried out using aniline hydrochloride as an unsubstituted counterpart, which yields polyaniline nanofibers. WXRD analysis confirmed the presence of a sharp peak at lower angle at 2theta = 7.3 degrees ( d-spacing of 13.4 A) in hydroxyl-substituted nanospheres with respect to enhancement of solid-state ordered crystalline domains, whereas unsubstituted nanofibers were found to be highly amorphous. Vitamin C was employed as an analyte to trace the molecular interaction at the nanosphere surface and study the influence of nanosurface functionalization on the sensing ability of biomolecules. The bishydroxyl-functionalized polyaniline nanospheres were found to show efficient molecular interactions toward vitamin C, whereas nanospheres with a monohydroxyl group or unsubstituted nanofibers failed as sensing materials. In a nut shell, in the present investigation, for the first time, we have proved the importance of surface functionalization of polyaniline nanomaterial, exclusively nanospheres, using hydroxyl groups for studying the molecular interactions at the nanosurfaces with biomolecules such as vitamin C.


Assuntos
Compostos de Anilina/química , Ácido Ascórbico/química , Radical Hidroxila/química , Nanopartículas/química , Nanosferas/química , Nanotecnologia/métodos , Acetanilidas/química , Concentração de Íons de Hidrogênio , Espectroscopia de Ressonância Magnética , Espectrometria de Massas/métodos , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Modelos Químicos , Polímeros/química , Espectroscopia de Infravermelho com Transformada de Fourier
16.
Antonie Van Leeuwenhoek ; 94(2): 207-16, 2008 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-18357511

RESUMO

Expression of Pseudomonas aeruginosa genes PHA synthase1 (phaC1) and (R)-specific enoyl CoA hydratase1 (phaJ1) under a lacZ promoter was able to support production of a copolymer of Polyhydroxybutyrate (PHB) and medium chain length polyhydoxyalkanoates (mcl-PHA) in Escherichia coli. In order to improve the yield and quality of PHA, plasmid bearing the above genes was introduced into E. coli JC7623, harboring integrated beta-ketothiolase (phaA) and NADPH dependent-acetoacetyl CoA reductase (phaB) genes from a Bacillus sp. also driven by a lacZ promoter. The recombinant E. coli (JC7623ABC1J1) grown on various fatty acids along with glucose was found to produce 28-34% cellular dry weight of PHA. Gas chromatography and (1)H Nuclear Magnetic Resonance analysis of the polymer confirmed the ability of the strain to produce PHB-co-Hydroxy valerate (HV)-co-mcl-PHA copolymers. The ratio of short chain length (scl) to mcl-PHA varied from 78:22 to 18:82. Addition of acrylic acid, an inhibitor of beta-oxidation resulted in improved production (3-11% increase) of PHA copolymer. The combined use of enzymes from Bacillus sp. and Pseudomonas sp. for the production of scl-co-mcl PHA in E. coli is a novel approach and is being reported for the first time.


Assuntos
Bacillus/enzimologia , Escherichia coli/metabolismo , Engenharia Genética/métodos , Poli-Hidroxialcanoatos/biossíntese , Pseudomonas/enzimologia , Acetil-CoA C-Aciltransferase/genética , Acetil-CoA C-Aciltransferase/metabolismo , Aciltransferases/genética , Aciltransferases/metabolismo , Oxirredutases do Álcool/genética , Oxirredutases do Álcool/metabolismo , Bacillus/genética , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Biomassa , Biopolímeros/biossíntese , Biopolímeros/química , Biopolímeros/genética , Vias Biossintéticas , Escherichia coli/química , Escherichia coli/genética , Escherichia coli/crescimento & desenvolvimento , Expressão Gênica , Poli-Hidroxialcanoatos/química , Poli-Hidroxialcanoatos/genética , Pseudomonas/genética
17.
Langmuir ; 22(13): 5952-7, 2006 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-16768535

RESUMO

We demonstrate here, for the first time, a unique strategy for conducting polyaniline nanofibers based on renewable resources. Naturally available cardanol, which is an industrial waste and main pollutant from the cashew nut industry, is utilized for producing well-defined polyaniline nanofibers. A new amphiphilic molecule is designed and developed from cardanol, which forms a stable emulsion with aniline for a wide composition range in water (1:1 to 1:100 dopant/aniline mole ratio) to produce polyaniline nanofibers. The scanning electron microscopy and transmission electron microscopy analysis of the nanofibers reveals that the dopant/aniline ratio plays a major role in determining the shape and size of polyaniline nanofibers. The nanofiber length increases with the increase in the dopant/aniline ratio, and perfectly linear, well-defined nanofibers of lengths as long as 7-8 muM were produced. The amphiphilic dopant has a built-in head-to-tail geometry and effectively penetrates into the polyaniline chains to form highly organized nanofibers. Wide-angle X-ray diffraction (WXRD) spectra of the nanofibers showed a new peak at 2theta = 6.3 (d spacing = 13.9 A) corresponding to the three-dimensional solid-state ordering of polyaniline-dopant chains, and this peak intensity increases with increase in the nanofiber length. The comparison of morphology and WXRD reveals that high ordering in polyaniline chains results in the formation of long, well-defined nanofibers, and this direct correlation for the polyaniline nanofibers with solid-state ordering has been established. The conductivity of the polyaniline nanofibers also increases with increase in the solid-state ordering rather than increasing with the extent of doping. The polyaniline nanofibers are freely soluble in water and possess high environmental and thermal stability up to 300 degrees C for various applications.

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