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1.
Molecules ; 28(20)2023 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-37894696

RESUMO

The progressive trend of utilizing bioactive materials constitutes diverse materials exhibiting biocompatibility. The innovative aspect of this research is the tuning of the thermo-mechanical behavior of polyurethane (PU) composites with improved biocompatibility for vibrant applications. Polycaprolactone (CAPA) Mn = 2000 g-mol-1 was used as a macrodiol, along with toluene diisocyanate (TDI) and hexamethylene diisocyanate (HMDI), to develop prepolymer chains, which were terminated with 1,4 butane diol (BD). The matrix was reinforced with various concentrations of chitosan (1-5 wt %). Two series of PU composites (PUT/PUH) based on aromatic and aliphatic diisocyanate were prepared by varying the hard segment (HS) ratio from 5 to 30 (wt %). The Fourier-transformed infrared (FTIR) spectroscopy showed the absence of an NCO peak at 1730 cm-1 in order to confirm polymer chain termination. Thermal gravimetric analysis (TGA) showed optimum weight loss up to 500 °C. Dynamic mechanical analysis (DMA) showed the complex modulus (E*) ≥ 200 MPa. The scanning electron microscope (SEM) proved the ordered structure and uniform distribution of chain extender in PU. The hemolytic activities were recorded up to 15.8 ± 1.5% for the PUH series. The optimum values for the inhibition of biofilm formation were recorded as 46.3 ± 1.8% against E. coli and S. aureus (%), which was supported by phase contrast microscopy.


Assuntos
Quitosana , Poliuretanos , Poliuretanos/química , Quitosana/química , Escherichia coli , Staphylococcus aureus , Bioensaio
2.
Geriatr Nurs ; 42(2): 447-459, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33714024

RESUMO

The University of California, Los Angeles Alzheimer's and Dementia Care (ADC) program enrolls persons living with dementia (PLWD) and their family caregivers as dyads to work with nurse practitioner dementia care specialists to provide coordinated dementia care. At one year, despite disease progression, overall the PLWDs' behavioral and depressive symptoms improved. In addition, at one-year, overall caregiver depression, strain, and distress related to behavioral symptoms also improved. However, not all dyads enrolled in the ADC program showed improvement in these outcomes. We conducted a mixed qualitative-quantitative study to explore why some participants did not benefit and what could be changed in this and other similar dementia management programs to increase the percentage who benefit. Semi-structured interviews (N=12) or surveys (N=41) were completed with 53 caregivers by telephone, mail and online. Seven areas for potential program improvement were identified from the first 12 interviews. These included: recommendations that did not match caregivers' perceived care needs, barriers to accessing care and utilizing resources, differing care needs based on stage of dementia, needing services not offered by the ADC, needing more education or support, behavioral recommendations that the caregiver felt did not work, and poor rapport of the dementia expert with caregivers. Despite having been identified as having had no clinical benefit from participating in the program, most caregivers (85%) reported that the program was very beneficial or extremely beneficial. Respondents identified the close, longitudinal relationship and access to a dementia care expert as particularly beneficial. This dichotomy highlights that perceived benefit for most of the interviewed caregivers was not captured with the formal instruments used by the program.


Assuntos
Doença de Alzheimer , Demência , Cuidadores , Demência/terapia , Humanos , Telefone
3.
Int J Biol Macromol ; 257(Pt 2): 128674, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38070799

RESUMO

This study introduces a novel biobased textile finishing agent synthesized as waterborne polyurethane dispersions (FCCB-WPUDs), utilizing bio-based monomers like fenugreek oil-based polyol, corn oil-derived emulsifier, and cellulose acetate butyrate (CAB) chain extender. The FCCB-WPUDs were prepared through the prepolymer polymerization method and characterized using FTIR, TGA, DMA, SEM, DLS, and swelling tests. Their application to poly-cotton fabrics significantly improved various fabric properties. The enhancements included increased washing fastness (from 3/4 ± 0.01 to 4 ± 0.02 for dyed and 3 ± 0.02 to 4/5 ± 0.02 for printed fabrics), rubbing fastness (from 3 ± 0.02 to 4/5 ± 0.03 for dyed and 4 ± 0.02 to 4/5 ± 0.03 for printed fabrics), and perspiration fastness (from 3 ± 0.02 to 4 ± 0.03 for acidic dyed and 3/4 ± 0.02 to 4 ± 0.02 for alkaline printed fabrics). Additionally, tear strengths improved significantly (from 13.66 ± 0.04 N/m to 20.53 ± 0.06 N/m for warp dyed and 10.85 ± 0.06 N/m to 15.14 ± 0.06 N/m for warp printed fabrics), along with tensile strengths (from 327 ± 5.38 N/m to 361 ± 3.26 N/m for warp dyed and 357 ± 5.34 N/m to 449 ± 4.90 N/m for warp printed fabrics). These improvements correlated with increasing CAB moles as a chain extender. This research presents a cost-effective and simple biobased method for textile finishing, offering an alternative to petrochemical-based monomers in conventional WPUD preparation.


Assuntos
Fibra de Algodão , Poliuretanos , Têxteis , Corantes , Polimerização
4.
Int J Biol Macromol ; 262(Pt 1): 129350, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38242400

RESUMO

Chitosan-based polymers have enormous structural tendencies to build bioactive materials with novel characteristics, functions, and various applications, mainly in liver tissue engineering (LTE). The specific physicochemical, biological, mechanical, and biodegradation properties give the effective ways to blend these biopolymers with synthetic and natural polymers to fabricate scaffolds matrixes, sponges, and complexes. A variety of natural and synthetic biomaterials, including chitosan (CS), alginate (Alg), collagen (CN), gelatin (GL), hyaluronic acid (HA), hydroxyapatite (HAp), polyethylene glycol (PEG), polycaprolactone (PCL), poly(lactic-co-glycolic) acid (PGLA), polylactic acid (PLA), and silk fibroin gained considerable attention due to their structure-properties relationship. The incorporation of CS within the polymer matrix results in increased mechanical strength and also imparts biological behavior to the designed PU formulations. The significant and growing interest in the LTE sector, this review aims to be a detailed exploration of CS-based polymers biomaterials for LTE. A brief explanation of the sources and extraction, properties, structure, and scope of CS is described in the introduction. After that, a full overview of the liver, its anatomy, issues, hepatocyte transplantation, LTE, and CS LTE applications are discussed.


Assuntos
Quitosana , Engenharia Tecidual , Engenharia Tecidual/métodos , Polímeros/química , Quitosana/química , Alicerces Teciduais/química , Materiais Biocompatíveis/química , Fígado
5.
RSC Adv ; 14(2): 779-793, 2024 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-38174249

RESUMO

The intense urge to replace conventional polymers with ecofriendly monomers is a step towards green products. The novelty of this study is the extraction of starch from the biowaste of wheat bran (WB) and banana peel (BP) for use as a monomer in the form of chain extenders. For the synthesis of polyurethane (PU) elastomers, polyethylene glycol (PEG) bearing an average molecular weight Mn = 1000 g mol-1 was used as a macrodiol, which was reacted with isophorone diisocyanate (IPDI) to develop NCO-terminated prepolymer chains. These prepolymer chains were terminated with chain extenders. Two series of linear PU elastomers were prepared by varying the concentration of chain extenders (0.5-2.5 mol%), inducing a variation of 40 to 70 wt% in the hard segment (HS). Fourier-transform infrared (FTIR) spectroscopy confirmed the formation of urethane linkages. Thermal gravimetric analysis (TGA) showed a thermal stability of up to 250 °C. Dynamic mechanical analysis (DMA) revealed a storage modulus (E') of up to 140 MPa. Furthermore, the hemolytic activities of up to 8.97 ± 0.1% were recorded. The inhibition of biofilm formation was investigated against E. coli and S. aureus (%), which was supported by phase contrast microscopy.

6.
R Soc Open Sci ; 11(2): 231094, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38356872

RESUMO

Owing to the broad applications of quaternary ammonium salts (QAS), we present the synthesis of benzimidazolium-based analogues with variation in the alkyl and alkoxy group at N-1 and N-3 positions. All the compounds were characterized by spectroscopic techniques and found stable to air and moisture both in the solid and solution state. Moreover, molecular structures were established through single-crystal X-ray diffraction studies. The crystal packing of the compounds was stabilized by numerous intermolecular interactions explored by Hirshfeld surface analysis. The enrichment ratio was calculated for the pairs of chemical species to acquire the highest propensity to form contacts. Void analysis was carried out to check the mechanical response of the compounds. Furthermore, theoretical investigations were also performed to explore the optoelectronic properties of compounds. Natural population analysis (NPA) has been conducted to evaluate the distribution of charges on the synthesized compounds, whereas high band gaps of the synthesized compounds by frontier molecular orbital (FMO) analysis indicated their stability. Nonlinear optical (NLO) analysis revealed that the synthesized QAS demonstrates significantly improved NLO behaviour than the standard urea.

7.
Int J Biol Macromol ; 278(Pt 2): 134657, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39147346

RESUMO

This research addresses the need for enhanced biomaterials by investigating the influence of the NCO/OH ratio on sodium alginate-based polyurethane elastomers(Al-PUEs), offering novel insights into their structural, thermal, mechanical and swelling behavior. Al-PUEs were prepared by blending the chain extenders with key ingredients in a specific molar ratio using aliphatic HMDI and HTPB monomers. The chemical linkages, crystalline behavior, homogeneity, and surface morphology of PUEs were evaluated by FT-IR, XRD, SEM, and EDX analysis. Thermo-mechanical studies were performed using TGA, DSC and tensile testing. Swelling behavior and absorption analysis were analyzed in DMSO and water. The analysis indicated that the hydrophilicity and swelling behavior of the prepared PUEs were affected by the addition of sodium alginate content. The results exhibit the tailor-made network structure of Al-PUEs, resulting in better thermal stability, elasticity of materials via stress-strain behavior and marvelous characteristic features than traditional high-tech yields. Furthermore, the resulting Al-PUEs are potential candidates for biomedical implants.


Assuntos
Alginatos , Elastômeros , Isocianatos , Poliuretanos , Poliuretanos/química , Alginatos/química , Elastômeros/química , Isocianatos/química , Materiais Biocompatíveis/química , Resistência à Tração , Espectroscopia de Infravermelho com Transformada de Fourier , Teste de Materiais , Interações Hidrofóbicas e Hidrofílicas , Temperatura
8.
ACS Omega ; 8(37): 33310-33320, 2023 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-37744844

RESUMO

Petrochemical costs, limited fossil fuel reserves, and concerns about greenhouse gas emissions have raised interest in developing renewable approaches for synthesizing biobased polyurethanes. This study aims to solve these problems by making nanocrystalline hydroxyapatite (HA) reinforcement from waste chicken eggshells and adding it to polyurethane synthesis through in situ polymerization. The novelty of the research lies in the utilization of HA as a reinforcement material and renewable resources for polyurethane production. The results confirm that HA was successfully added to the polyurethane backbone. Fourier transform infrared (FTIR) analysis confirmed that the NCO groups were changed to urethane linkages. TGA examination demonstrated that the samples exhibited thermal stability up to 457 °C with a mass loss of 61%, indicating enhanced thermal stability. DMA measurements showed improved mechanical properties of the synthesized polyurethanes, with storage modulus (E'), complex modulus (E*), and compliance complex (D*) values of 0.177, 22.522, and 0.660 MPa-1, respectively. SEM analysis confirmed the homogeneous surface and well-dispersed HA reinforcement. Swelling characteristics revealed an optimum absorption of 30% H2O, 35% CH3OH, and 45% CCl4. Polyurethane composites exhibited significant chemical resistance and hydrolytic stability in acidic and basic media. Additionally, the composites demonstrated efficient adsorption of methyl orange from wastewater, with the PUHCI series achieving a maximum adsorption capacity of 85.50 mg/g under optimal conditions of 0.030 g/mL dose, 45 °C temperature, 2.5 h contact time, and pH 6.0..

9.
ACS Omega ; 8(38): 35307-35320, 2023 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-37779999

RESUMO

Polymorphism is an exciting feature of chemical systems where a compound can exist in different crystal forms. The present investigation is focused on the two polymorphic forms, triclinic (MSBT) and monoclinic (MSBM), of ethyl 3-iodo-4-((4-methylphenyl)sulfonamido)benzoate prepared from ethyl 4-amino-3-iodobenzoate. The prepared polymorphs were unambiguously confirmed by single-crystal X-ray diffraction (SC-XRD) analysis. According to the SC-XRD results, the molecular configurations of both structures are stabilized by intramolecular N-H···I and C-H···O bonding. The crystal packing of MSBT is different as compared to the crystal packing of MSBM because MSBT is crystallized in the triclinic crystal system with the space group P1̅, whereas MSBM is crystallized in the monoclinic crystal system with the space group P21/c. The molecules of MSBT are interlinked in the form of dimers through N-H···O bonding to form R22(8) loops, while the MSBM molecules are connected with each other in the form of an infinite chain through C-H···O bonding. The crystal packing of both compounds is further stabilized by off-set π···π stacking interactions between phenyl rings, which is found stronger in MSBM as compared to in MSBT. Moreover, Hirshfeld surface exploration of the polymorphs was carried out, and the results were compared with the closely related literature structure. Accordingly, the supramolecular assembly of these polymorphs is mainly stabilized by noncovalent interactions or intermolecular interactions. Furthermore, a density functional theory (DFT) study was also carried out, which provided good support for the SC-XRD and Hirshfeld studies, suggesting the formation of both intramolecular and intermolecular interactions for both compounds.

10.
Environ Sci Pollut Res Int ; 29(1): 293-311, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34523090

RESUMO

The disposal of dye-contaminated wastewater is a major concern around the world for which a variety of techniques are used for its treatment. The photocatalytic treatment of dye-contaminated wastewater is one of the treatment methods. Semiconductor-assisted photocatalytic treatment of dye-contaminated wastewater has gained pronounced attention recently. This review outlines the recent advancements in the photocatalytic treatment of dye-contaminated wastewater. The photocatalytic degradation of dyes follows three types of mechanisms: (1) dye sensitization through charge injection, (2) indirect dye degradation through oxidation/reduction, and (3) direct photolysis of dye. Several experimental parameters like initial concentration of dyes, pH, and catalyst dosage significantly affect the photocatalytic degradation of dyes. The photocatalytic materials can be categorized into three generations. The single-component (e.g., ZnO, TiO2) and multiple component semiconductor metal oxides (e.g., ZnO-TiO2, Bi2O3-ZnO) are categorized as first-generation and second-generation photocatalysts, respectively. The photocatalysts dispersed on an inert solid substrate (e.g., Ag-Al2O3, ZnO-C) are classified as third-generation photocatalysts. Finally, we reviewed the challenges that affect the photocatalytic degradation of dyes.


Assuntos
Corantes , Águas Residuárias , Catálise , Fotólise , Semicondutores
11.
Polymers (Basel) ; 14(3)2022 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-35160561

RESUMO

The texture and molecular weight of polymer drastically affect the adhesion or tack strength. Waterborne polyurethane dispersions (WBPU) have been prepared using two different macrodiols of hydroxyl terminated polybutadiene (HTPB; Mn = 2912 g/mol-1) and four compositions of Polypropylene glycol (PPG Mn = 425, 1000, 2000, 2700 g/mol-1). The contents of the macrodiols have been varied using HTPB as 5, 10 and 15 mol%. The prepolymer of HTPB and Poly propylene glycol (PPG) have been developed using 4,4-Methylene bis(cyclohexyl isocyanate) (H12MDI) which is extended using 1, 4 butanediol (BD) followed by the dispersion of polymers in deionized water. Fourier Transform Infra-red spectroscopy (FTIR) is used to confirm the desired PU linkage. The probe tack graphs for tack analysis have not shown any plateau indicating absence of fibrillation. Two different values of glass transition temperature (Tg) have been observed for each dispersion using Differential Scanning Calorimetry(DSC). Storage modulus (E') up to 3.97 MPa and (tanδ/E') from 0.01-0.30 MPa-1 has been observed via Dynamic Mechanical Analysis (DMA). Introducing the HTPB has resulted in a decrease in the values of (tanδ/E'). No adhesion favorable parameters have been retrieved, indicating the molar variation a key factor in the development of anti-tack dispersions.

12.
Polymers (Basel) ; 14(17)2022 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-36080776

RESUMO

The search for renewable resources that can replace petroleum products is not only nerve-wracking, but also perplexing, as there is an abundance of plants that have yet to be explored. In this project, virgin castor oil was converted to polyol in two steps: epoxidation and hydroxylation. The resulting polyol was used to synthesize two series of water-borne polyurethane dispersions (WPUDs). The effects of the diisocyanates on the final product were evaluated. Isophorone diisocyanate (IPDI) and dicyclohexylmethane-4,4'-diisocyanate (H12MDI) were used as the hard segment (HS) up to 72 wt%, along with 1-4 butanediol (BD) as the chain extender, for the dispersions. Fourier transform infrared spectroscopy (FTIR) confirmed the bonds required for the synthesis of the dispersions. Thermogravimetric analysis (TGA) showed the multistep degradation for both series: maximum degradation took place at 500 °C for IPDI and 600 °C for H12MDI-based series. Scanning electron microscopy (SEM) showed phase-segmented morphology. Hemolytic activity was observed at biologically safe levels of up to 7.5% for H12MDI-based series. Inhibition of biofilm formation showed comparable results against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus): up to 46%. The results were also confirmed by phase contrast microscopy.

13.
ACS Omega ; 6(2): 1426-1435, 2021 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-33490802

RESUMO

Photocatalysis is one of the techniques used for the eradication of organic pollutants from wastewater. In this study, Co-ZnO was tested as a photocatalyst for the degradation of methyl orange under irradiation of visible light. Co-ZnO loaded with 5%, 10%, and 15% Co was prepared by the precipitation method. The advanced techniques including X-ray diffraction, X-ray photoelectron spectroscopy, diffuse reflectance UV-visible spectroscopy, photoelectrochemical measurements, temperature-programmed desorption, photoluminescence, and fluorescence spectroscopy related to OH• measurements were used for characterization of prepared Co-ZnO. Experiments showed that 10% Co-ZnO was a highly efficient catalyst for the photodegradation of methyl orange as compared to ZnO. The enhanced photocatalytic activity of Co-ZnO is attributed to the implantation of Co which inhibits the electron-hole recombination. A 100 mg/L solution of methyl orange dye was completely degraded within 130 min. The reaction kinetics has been described in terms of the Eley-Rideal mechanism.

14.
Int J Biol Macromol ; 191: 861-871, 2021 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-34571126

RESUMO

Compressed tablet formation from granular drug require binder with Cohesiveness property. Plants mucilage as pharmaceutical excipients are available. In this study, biocompatible date palm mucilage was encapsulated with silver nano particles for sustained drug release to provoke an immune response. Nano formulated mucilage was characterized by UV/VIS, FTIR, XRD, SEM/EDX spectrophotometry. UV/VIS spectra revealed an intense surface plasmon resonance peak at 406 nm for spherical mono dispersed silver nano formulated mucilage resulted from efficient reduction of silver ions to AgNPs. Zeta sizer disclosed the emergence of single peak at 139.7 nm with 100% intensity. Crude mucilage exhibited number of peaks in the region of 4000-500 cm-1 by FT-IR spectroscopy whereas purified as well as nano formulated samples showed somewhat different pattern of peaks in addition to peaks of crude sample. XRD spectra of crude mucilage revealed somewhat regular pattern while purified and modified mucilage displayed irregular structure. In SEM analysis, crude mucilage was appeared as granular that turned into porous network with entangled tiny silver nano spheres. A controlled release of drug levofloxacin hemihydrate was evaluated using crude/ nano formulated mucilage as excipient. Nano formulated mucilage delayed the onset exposure of drug in gastric medium giving recommendations as value added bio binder for drug to the target organ.


Assuntos
Liberação Controlada de Fármacos , Nanopartículas/química , Mucilagem Vegetal/química , Antibacterianos/administração & dosagem , Células Cultivadas , Colo/metabolismo , Humanos , Levofloxacino/administração & dosagem , Phoeniceae/química
15.
Polymers (Basel) ; 13(3)2021 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-33573168

RESUMO

The exceptional behavior of graphene has not yet been entirely implicit in the polymer matrix. To explore this fact in the present work, two series of Polyurethan (PU) composites were synthesized. The structural modification was observed by the use of two different diisocyanate of methylene diisocyanate (MDI) and hexamethylene diisocyanate (HMDI) in hydroxylterminated polybutadiene (HTPB) by using I,4 Butane diol (BD) as the chain extender. The variation in hard segment up to 25 (wt.%) in both series led to significant changes in the mechanical behavior of graphene oxide (GO) induced composites. Both series were prepared by an in situ polymerization process. Fourier transform infrared (FTIR) analysis showed a peak in the region of 1700 cm-1, which confirmed the conversion of the NCO group into urethane linkages. Thermal gravimetric analysis (TGA) revealed a thermal stability up to 450 °C @ 90% weight loss. The swelling behavior showed the optimum uptake of 30% of water and 40% of dimethyl sulfoxide (DMSO) with aliphatic diisocyanate. The values of storage modulus (E'), complex modulus (E*), and compliance complex (D*) were observed up to 7 MPa, 8 Mpa, and 0.7 MPa-1, respectively. The degree of entanglement (N) values were calculated from DMA and were found in the range of 1.7 × 10-4 (mol/m3). Phase segregation of PU was observed by scanning electron microscopy (SEM), elucidating the morphology of composites.

16.
Front Public Health ; 9: 757089, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-35265582

RESUMO

Low- and middle-income countries (LMICs) endure an asymmetrically high burden of worldwide disease and death caused by chronic respiratory diseases (CRDs), i.e., asthma, emphysema, bronchiectasis, and post-tuberculosis lung disease (PTLD). CRDs are firmly related with indigence, infectious diseases, and other non-communicable diseases (NCDs) and add to complex multi-disease with great impact on the lives and livelihood of those affected. The pertinence of CRDs to health and demographic wellbeing is relied upon to increment in the long time ahead, as expectations of life rise and the contending dangers of right on time youth mortality and irresistible infections level. The WHO has distinguished the counteraction and control of NCDs as an earnest improvement issue and crucial for the sustainable development goals (SDSs) by 2030. In this review, we center on CRDs in LMICs. We examine the early life roots of CRDs, challenges in their avoidance, identification and administration in LMICs, and the pathways to resolve for accomplish valid widespread wellbeing inclusion.


Assuntos
Doenças Transmissíveis , Doenças não Transmissíveis , Adolescente , Países em Desenvolvimento , Humanos , Renda , Pulmão , Doenças não Transmissíveis/epidemiologia
17.
Int J Biol Macromol ; 146: 243-252, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31891704

RESUMO

Starch/chitosan modified polyurethanes (PUs) were synthesized by step growth polymerization reaction between -NCO terminated prepolymer and chain extenders (1,4-Butanediol/starch/chitosan). Isophorone diisocyanate (IPDI) was reacted with hydroxyl-terminated polybutadiene (HTPB) to synthesize prepolymer and was further reacted with different moles ratio of starch/chitosan to produced five samples of polyurethane (PU). These samples were characterized by Fourier transformed infrared (FTIR) and Proton nuclear magnetic resonance (1H NMR) spectroscopy. The surface characterizations of PUs were done by scanning electron microscope (SEM). Thermogravimetric analysis showed that the thermal stability of PUs was higher when the mixture of both natural materials was used at equal amounts. It is concluded that combination of both starch and chitosan are efficient for the synthesis of PUs.


Assuntos
Quitosana/química , Poliuretanos/química , Amido/química
18.
Int J Biol Macromol ; 148: 415-423, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-31923497

RESUMO

Waxy corn starch modified polyurethane elastomers were synthesized by step growth polymerization reaction between NCO-terminated prepolymer and chain extenders (1,4-butanediol/starch). Isophorone diisocyanates (IPDI) was reacted with hydroxyl terminated polybutadiene (HTPB) to synthesize prepolymer that was reacted with different moles of 1,4-butanediol (1,4-BDO) and starch to produced five samples of polyurethane. These specimens were analyzed by Fourier transformed infrared (FTIR) and proton Nuclear Magnetic Resonance (1H NMR) spectroscopy to determine the structural information. However, role of starch as chain extender was examined by gel permeation chromatography (GPC). Additionally, starch increased the thermal stability of PUs as compared to the conventional chain extender (1,4-BDO). Over all, this work has been designed to develop biodegradable polyurethanes that could be used in biomedical systems.


Assuntos
Elastômeros/química , Poliuretanos/química , Amido/química , Zea mays/química , Materiais Biocompatíveis/química , Técnicas de Química Sintética , Estrutura Molecular , Poliuretanos/síntese química , Espectroscopia de Prótons por Ressonância Magnética , Espectroscopia de Infravermelho com Transformada de Fourier , Termogravimetria
19.
J Food Prot ; 83(8): 1284-1288, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32678886

RESUMO

ABSTRACT: A total of 133 samples of whole wheat and barley grains and wheat and barley flour collected from retail markets in the main cities of Punjab, Pakistan, were analyzed for the mycotoxin fumonisin B1 (FB1) using reverse phase high-performance liquid chromatography with fluorescence detection. Of these samples, 120 (90%) were positive for FB1, and 75 (63%) of the 120 positive samples had FB1 concentrations higher than the European Union maximum (200 µg/kg). The limit of detection was 4 µg/kg. The highest mean (±SD) concentration of FB1 was found in whole wheat samples, 980.5 ± 211.4 µg/kg. The calculated dietary intakes of FB1 from wheat and barley flours were 4,456 and 503.7 ng/g of body weight per day, respectively.


Assuntos
Fumonisinas , Hordeum , Contaminação de Alimentos/análise , Fumonisinas/análise , Paquistão , Triticum
20.
Appl Biochem Biotechnol ; 149(3): 255-64, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18500586

RESUMO

The objective of this study was to exploit the decolorization potential of a newly isolated white-rot fungus Schizophyllum commune IBL-6 for the biodegradation of reactive textile dye Cibacron Red FN-2BL. In the initial decolorization study of 10 days, it was observed that S. commune IBL-6 was a better decolorizer of Cibacron Red FN-2BL. Various process parameters like composition of basal nutrient medium, pH, temperature, additional carbon and nitrogen sources, and initial dyestuff concentration were optimized to develop an economic decolorization process. The optimum dye decolorization was achieved in basal nutrient medium II containing 0.1% Cibacron Red FN-2BL and supplemented with 1% glucose after 3 days incubation at pH 4.5 and 30 degrees C. All the additional carbon sources were found to enhance decolorization process, whereas most of the nitrogen supplements caused fungal-growth inhibition. The pattern of enzymes involved in the biodegradation of this dye was studied, and manganese peroxidase was found to be the major peroxidase with minor lignin peroxidase and laccase activities.


Assuntos
Cor , Corantes/metabolismo , Schizophyllum/metabolismo
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