WorldWideScience

Sample records for aliphatic biodegradable photoluminescent

  1. Development of aliphatic biodegradable photoluminescent polymers

    Science.gov (United States)

    Yang, Jian; Zhang, Yi; Gautam, Santosh; Liu, Li; Dey, Jagannath; Chen, Wei; Mason, Ralph P.; Serrano, Carlos A.; Schug, Kevin A.; Tang, Liping

    2009-01-01

    None of the current biodegradable polymers can function as both implant materials and fluorescent imaging probes. The objective of this study was to develop aliphatic biodegradable photoluminescent polymers (BPLPs) and their associated cross-linked variants (CBPLPs) for biomedical applications. BPLPs are degradable oligomers synthesized from biocompatible monomers including citric acid, aliphatic diols, and various amino acids via a convenient and cost-effective polycondensation reaction. BPLPs can be further cross-linked into elastomeric cross-linked polymers, CBPLPs. We have shown representatively that BPLP-cysteine (BPLP-Cys) and BPLP-serine (BPLP-Ser) offer advantages over the traditional fluorescent organic dyes and quantum dots because of their preliminarily demonstrated cytocompatibility in vitro, minimal chronic inflammatory responses in vivo, controlled degradability and high quantum yields (up to 62.33%), tunable fluorescence emission (up to 725 nm), and photostability. The tensile strength of CBPLP-Cys film ranged from 3.25 ± 0.13 MPa to 6.5 ± 0.8 MPa and the initial Modulus was in a range of 3.34 ± 0.15 MPa to 7.02 ± 1.40 MPa. Elastic CBPLP-Cys could be elongated up to 240 ± 36%. The compressive modulus of BPLP-Cys (0.6) (1:1:0.6 OD:CA:Cys) porous scaffold was 39.60 ± 5.90 KPa confirming the soft nature of the scaffolds. BPLPs also possess great processability for micro/nano-fabrication. We demonstrate the feasibility of using BPLP-Ser nanoparticles (“biodegradable quantum dots”) for in vitro cellular labeling and noninvasive in vivo imaging of tissue engineering scaffolds. The development of BPLPs and CBPLPs represents a new direction in developing fluorescent biomaterials and could impact tissue engineering, drug delivery, bioimaging. PMID:19506254

  2. Matrix-assisted laser desorption/ionization mass spectrometric analysis of aliphatic biodegradable photoluminescent polymers using new ionic liquid matrices.

    Science.gov (United States)

    Serrano, Carlos A; Zhang, Yi; Yang, Jian; Schug, Kevin A

    2011-05-15

    In this study, two novel ionic liquid matrices (ILMs), N,N-diisopropylethylammonium 3-oxocoumarate and N,N-diisopropylethylammonium dihydroxymonooxoacetophenoate, were tested for the structural elucidation of recently developed aliphatic biodegradable polymers by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). The polymers, formed by a condensation reaction of three components, citric acid, octane diol, and an amino acid, are fluorescent, but the exact mechanism behind their luminescent properties has not been fully elucidated. In the original studies, which introduced the polymer class (J. Yang et al., Proc. Natl. Acad. Sci. USA 2009, 106, 10086-10091), a hyper-conjugated cyclic structure was proposed as the source for the photoluminescent behavior. With the use of the two new ILMs, we present evidence that supports the presence of the proposed cyclization product. In addition, the new ILMs, when compared with a previously established ILM, N,N-diisopropylethylammonium α-cyano-3-hydroxycinnimate, provided similar signal intensities and maintained similar spectral profiles. This research also established that the new ILMs provided good spot-to-spot reproducibility and high ionization efficiency compared with corresponding crystalline matrix preparations. Many polymer features revealed through the use of the ILMs could not be observed with crystalline matrices. Ultimately, the new ILMs highlighted the composition of the synthetic polymers, as well as the loss of water that was expected for the formation of the proposed cyclic structure on the polymer backbone.

  3. Study on biodegradable aromatic/aliphatic copolyesters

    Energy Technology Data Exchange (ETDEWEB)

    Yiwang Chen; Licheng Tan; Lie Chen; Yan, Yang; Xiaofeng Wang [Nanchang University, Nanchang (China). School of Materials Science and Engineering. Inst. of Polymer Materials]. E-mail: ywchen@ncu.edu.cn

    2008-04-15

    Progress on biodegradable aromatic/aliphatic copolyesters based on aliphatic and aromatic diacids, diols and ester monomers was reviewed. The aromatic/aliphatic copolyesters combined excellent mechanical properties with biodegradability. Physical properties and biodegradability of copolyesters varied with chain length of the aliphatic polyester segment and atacticity of copolyesters. The process ability of copolyesters could be improved significantly after incorporating a stiff chain segment through copolymerization of aliphatic polyesters with an aromatic liquid crystal element. The aromatic/aliphatic copolyesters as a new type of biodegradable materials could replace some general plastics in certain applications, namely biomedical and environmental friendly fields. (author)

  4. Biodegradation of aliphatic and aromatic polycarbonates.

    Science.gov (United States)

    Artham, Trishul; Doble, Mukesh

    2008-01-01

    Polycarbonate is one of the most widely used engineering plastics because of its superior physical, chemical, and mechanical properties. Understanding the biodegradation of this polymer is of great importance to answer the increasing problems in waste management of this polymer. Aliphatic polycarbonates are known to biodegrade either through the action of pure enzymes or by bacterial whole cells. Very little information is available that deals with the biodegradation of aromatic polycarbonates. Biodegradation is governed by different factors that include polymer characteristics, type of organism, and nature of pretreatment. The polymer characteristics such as its mobility, tacticity, crystallinity, molecular weight, the type of functional groups and substituents present in its structure, and plasticizers or additives added to the polymer all play an important role in its degradation. The carbonate bond in aliphatic polycarbonates is facile and hence this polymer is easily biodegradable. On the other hand, bisphenol A polycarbonate contains benzene rings and quaternary carbon atoms which form bulky and stiff chains that enhance rigidity. Even though this polycarbonate is amorphous in nature because of considerable free volume, it is non-biodegradable since the carbonate bond is inaccessible to enzymes because of the presence of bulky phenyl groups on either side. In order to facilitate the biodegradation of polymers few pretreatment techniques which include photo-oxidation, gamma-irradiation, or use of chemicals have been tested. Addition of biosurfactants to improve the interaction between the polymer and the microorganisms, and blending with natural or synthetic polymers that degrade easily, can also enhance the biodegradation.

  5. Biodegradation of aliphatic and aromatic polycarbonates.

    Science.gov (United States)

    Artham, Trishul; Doble, Mukesh

    2008-01-01

    Polycarbonate is one of the most widely used engineering plastics because of its superior physical, chemical, and mechanical properties. Understanding the biodegradation of this polymer is of great importance to answer the increasing problems in waste management of this polymer. Aliphatic polycarbonates are known to biodegrade either through the action of pure enzymes or by bacterial whole cells. Very little information is available that deals with the biodegradation of aromatic polycarbonates. Biodegradation is governed by different factors that include polymer characteristics, type of organism, and nature of pretreatment. The polymer characteristics such as its mobility, tacticity, crystallinity, molecular weight, the type of functional groups and substituents present in its structure, and plasticizers or additives added to the polymer all play an important role in its degradation. The carbonate bond in aliphatic polycarbonates is facile and hence this polymer is easily biodegradable. On the other hand, bisphenol A polycarbonate contains benzene rings and quaternary carbon atoms which form bulky and stiff chains that enhance rigidity. Even though this polycarbonate is amorphous in nature because of considerable free volume, it is non-biodegradable since the carbonate bond is inaccessible to enzymes because of the presence of bulky phenyl groups on either side. In order to facilitate the biodegradation of polymers few pretreatment techniques which include photo-oxidation, gamma-irradiation, or use of chemicals have been tested. Addition of biosurfactants to improve the interaction between the polymer and the microorganisms, and blending with natural or synthetic polymers that degrade easily, can also enhance the biodegradation. PMID:17849431

  6. Study on the Synthesis and Biodegradation of Aliphatic Polyester

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    An aliphatic polyester, poly(hexalene adipate) (PHA) and an aliphatic copolyester, poly (hexalene adipate succinate) (PHAS) were synthesized by direct condensation of corresponding binary acid and binary alcohol in the presence of a catalyst, p-toluene sulfonic acid. The biodegradation of these polyesters were studied in the laboratory by enzyme attack and outdoor soil burial. The results show that these polyesters have good biodegradability and the copolyester PHAS, even displayed a better biodegradability than the polyester PHA. In the presence of Penicillium chrysogenum the weight loss reached 18.3% for the PHAS (film thickness 1.0 mm)and 9.1% for the PHA (film thickness 1.0 mm) after 28 days. Outdoor soil burial tests indicate that these polyesters also have good biodegradability in natural conditions. The weight loss reached 14.2% for PHAS (film thickness 0.1 mm) and 6.7% for PHA (film thickness 0.1mm) after burying in soil for 36 days.

  7. Hydrolytic And Enzymatic Degradation Characteristics Of Biodegradable Aliphatic Polysters

    Institute of Scientific and Technical Information of China (English)

    LI Suming

    2004-01-01

    Aliphatic polyesters, especially those derived from lactide (PLA), glycolide (PGA) and ε-caprolactone (PCL), are being investigated worldwide for applications in the field of surgery (suture material, devices for internal bone fracture fixation), pharmacology (sustained drug delivery systems), and tissue engineering (scaffold for tissue regeneration) [1,2]. This is mainly due to their good biocompatibility and variable degradability. These polymers present also a growing interest for environmental applications in agriculture (mulch films) and in our everyday life (packaging material)as the development of biodegradable materials is now considered as one of the potential solutions to the problem of plastic waste management.For both biomedical and environmental applications, it is of major importance to understand the degradation characteristics of the polymers. The hydrolytic degradation of aliphatic polyesters has been investigated by many research groups. Our group has shown that degradation of PLAGA large size devices is faster inside than at the surface. This heterogeneous degradation is due to the autocatalytic effect of carboxylic endgroups formed by ester bond cleavage. Moreover,degradation-induced morphological and compositional changes were also elucidated. In the case of PCL, the hydrolytic degradation is very slow due to its hydrophobicity and crystallinity.The enzymatic degradation of these polymers has been investigated by a number of authors. A specific enzyme, proteinase K, has been shown to have significant effects on PLA degradation. This enzyme preferentially degrade L-lactate units as opposed to D-lactate ones, amorphous zones as opposed to crystalline ones [3]. The enzymatic degradation of PCL polymers has also been investigated. A number of lipase-type enzymes were found to significantly accelerate the degradation of PCL despite its high crystallinity. In the case of PLA/PCL blends, the two components exhibited well separated crystalline domains

  8. Biodegradation of Trihalomethanes and Other Halogenated Aliphatic Compounds

    Science.gov (United States)

    Smith, G. B.

    1996-01-01

    The biological dehalogenation of common water pollutants such as trichloromethane (chloroform) and other halogenated aliphatic compounds was the subject of this project. Samples from diverse water environments such as from groundwater contaminated with halogenated compounds and wastewaters from regional treatment plants were studied to identify conditions that favor certain dehalogenation reactions over others. Gene probe analyses of DNA extracted from the dichlormethane-degrading wastewater indicated the presence of the gene coding for dichloromethane dehalogenase, indicating the genetic basis for the dechlorination activity observed. These studies indicate that methanogenic bacteria are the organisms responsible for the chloroform dechlorination. Dechlorination of a common chlorofluorocarbon (CFC-11) was identified in samples taken from a regional aquifer contaminated with halogenated aliphatic compounds.

  9. Biodegradation of Aliphatic-aromatic Coplyester under Thermophilic Conditions

    Directory of Open Access Journals (Sweden)

    Elsayed B. Belal

    2013-11-01

    Full Text Available The biodegradation of poly (tetramethylene adipate-co-tetramethylene terephthalate (BTA-copolyester as synthetic polyester was investigated under thermophilic conditions. Two efficient BTA degrading actinomycetes were isolated from compost at thermophilic phase. These strains were identified as Thermobifida fusca and Thermobispora bispora. The degradation rate for BTA films within 7 days was 17.12 and 16.96 mg/week.cm2 by T. fusca and T. bispora, respectively. The optimum BTA40:60 degradation conditions are obtained as pH7 and 55°C. The both strains exhibited a wider substrate spectrum as they are able to degrade synthetic polyesters (BTA40:60, PCL-S MaterBi ZF03U/A and natural polymers (poly-&beta-hydroxybutyric acid (PHB and carboxymethyl cellulose. It was shown that the extracellular hydrolyases activity from the both strains was induced in the presence of BTA-copolyester, while the presence of additional carbon sources such as glucose or a complex medium suppressed enzyme formation. Tributyrin as triglycerides was degraded by the both crude concentrated BTA-hydrolases. In contrast the enzyme was not capable to depolymerize the natural polymers PHB and carboxymethyl cellulose, although the organism itself degraded both types of polymers. The obtained results showed that the degradation rate with T. fusca BTA40:60-hydrolase was 3.67 mg/day.cm2 and was 3.5 mg/day.cm2 with T. bispora BTA40:60-hydrolase. The pH optimum for BTA-hydrolases was 7 with 20 and 100 mM phosphate buffer and it was 6 with 150 mM citrate buffer. Finally, it could be concluded that actinomycetes and their hydrolases play an outstanding role in recycling of biodegradable plastics under thermophilic phase during composting process.

  10. Effect of electron beam irradiation on the biodegradability of aromatic aliphatic copolyester film and their blend with corn starch

    International Nuclear Information System (INIS)

    Biodegradable and green plastics have been studied in the last years. The aim of this paper is to study the effect of electron beam irradiation on the biodegradability of aromatic aliphatic copolyester film and their blend with corn starch. The samples were irradiated at different doses 10 and 40 kGy in a linear accelerator. The biodegradability of the materials was evaluated by two methods: soil simulated and enzymatic. In the method enzymatic when it was used α-amylase, the irradiated samples presented faster biodegradation than the references non irradiated. The blend of aromatic aliphatic copolyester with corn starch (EcobrasR) irradiated presented a bigger biodegradability than the aromatic aliphatic copolyester (EcoflexR) film in both methods studied. (author)

  11. Biodegradable aliphatic-aromatic copolyester/corn starch blend composite reinforced with coffee parchment husk

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Valquiria A.; Teixeira, Jaciele G.; Gomes, Michelle G.; Ortiz, Angel V.; Oliveira, Rene R.; Scapin, Marcos A.; Moura, Esperidiana A.B. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Colombo, Maria A., E-mail: valquiriaalves36@yahoo.com.br [Faculdade de Tecnologia da Zona Leste (FATEC), Sao Paulo, SP (Brazil)

    2013-07-01

    In recent years, studies have shown that the addition of natural fiber or proper filler is an effective strategy for achieving improved properties in biodegradable polymer materials. Moreover, is especially important if such fibers are residues of agro-industrial processes. In this work, a promising technique to develop biodegradable polymer matrix composite based on aliphatic-aromatic copolyester/corn starch blend (Evela®) and coffee parchment husk, which is residue from coffee processing is described. The biodegradable polymeric blend (Evela®) with 5 % (w/w) of ball-milled coffee parchment husk fiber powder, with size ≤250 μm, without any modification was prepared by melt-mixing processing, using a twin screw extruder machine and then pelletized. In a second step, the pelletized Evela®)/coffee parchment (Composite) was then dried at 70 ± 2 deg C for 24 h in a circulating air oven, fed into injection molding machine and test specimens were obtained. The Composite specimen samples were irradiated using an electron beam accelerator, at radiation dose of 20 and 40 kGy, at room temperature in presence of air. The irradiated and non-irradiated samples were characterized by means of scanning electron microscopy (SEM), X-Ray diffraction (XRD), tensile tests and sol-gel analysis and the correlation between their properties was discussed. In addition, coffee parchment husk fiber characterization by SEM, EDS, XRD and WDXRF have also been carried out with a view to evaluate its importance in determining the end-use properties of the composite. (author)

  12. Biodegradable aliphatic-aromatic copolyester/corn starch blend composite reinforced with coffee parchment husk

    International Nuclear Information System (INIS)

    In recent years, studies have shown that the addition of natural fiber or proper filler is an effective strategy for achieving improved properties in biodegradable polymer materials. Moreover, is especially important if such fibers are residues of agro-industrial processes. In this work, a promising technique to develop biodegradable polymer matrix composite based on aliphatic-aromatic copolyester/corn starch blend (Evela®) and coffee parchment husk, which is residue from coffee processing is described. The biodegradable polymeric blend (Evela®) with 5 % (w/w) of ball-milled coffee parchment husk fiber powder, with size ≤250 μm, without any modification was prepared by melt-mixing processing, using a twin screw extruder machine and then pelletized. In a second step, the pelletized Evela®)/coffee parchment (Composite) was then dried at 70 ± 2 deg C for 24 h in a circulating air oven, fed into injection molding machine and test specimens were obtained. The Composite specimen samples were irradiated using an electron beam accelerator, at radiation dose of 20 and 40 kGy, at room temperature in presence of air. The irradiated and non-irradiated samples were characterized by means of scanning electron microscopy (SEM), X-Ray diffraction (XRD), tensile tests and sol-gel analysis and the correlation between their properties was discussed. In addition, coffee parchment husk fiber characterization by SEM, EDS, XRD and WDXRF have also been carried out with a view to evaluate its importance in determining the end-use properties of the composite. (author)

  13. Synthesis and characterization of biodegradable aliphatic polyesters using dibutylmagnesium as initiator

    Institute of Scientific and Technical Information of China (English)

    Lian Liu; Zhi Yong Wei; Min Qi

    2007-01-01

    Aliphatic polyesters were synthesized via the ring opening polymerization of the corresponding lactones initiated with dibutylmagnesium both in bulk and in solution.The resulting polymers were characterized by 1H, 13C NMR, GPC and XRD.The results indicated that dibutylmagnesium is an effective initiator for the ring opening polymerization of lactones.

  14. Exploring mild enzymatic sustainable routes for the synthesis of bio-degradable aromatic-aliphatic oligoesters.

    Science.gov (United States)

    Pellis, Alessandro; Guarneri, Alice; Brandauer, Martin; Acero, Enrique Herrero; Peerlings, Henricus; Gardossi, Lucia; Guebitz, Georg M

    2016-05-01

    The application of Candida antarctica lipase B in enzyme-catalyzed synthesis of aromatic-aliphatic oligoesters is here reported. The aim of the present study is to systematically investigate the most favorable conditions for the enzyme catalyzed synthesis of aromatic-aliphatic oligomers using commercially available monomers. Reaction conditions and enzyme selectivity for polymerization of various commercially available monomers were considered using different inactivated/activated aromatic monomers combined with linear polyols ranging from C2 to C12 . The effect of various reaction solvents in enzymatic polymerization was assessed and toluene allowed to achieve the highest conversions for the reaction of dimethyl isophthalate with 1,4-butanediol and with 1,10-decanediol (88 and 87% monomer conversion respectively). Mw as high as 1512 Da was obtained from the reaction of dimethyl isophthalate with 1,10-decanediol. The obtained oligomers have potential applications as raw materials in personal and home care formulations, for the production of aliphatic-aromatic block co-polymers or can be further functionalized with various moieties for a subsequent photo- or radical polymerization. PMID:26762794

  15. Kinetics of aerobic cometabolic biodegradation of chlorinated and brominated aliphatic hydrocarbons: A review.

    Science.gov (United States)

    Jesus, João; Frascari, Dario; Pozdniakova, Tatiana; Danko, Anthony S

    2016-05-15

    This review analyses kinetic studies of aerobic cometabolism (AC) of halogenated aliphatic hydrocarbons (HAHs) from 2001-2015 in order to (i) compare the different kinetic models proposed, (ii) analyse the estimated model parameters with a focus on novel HAHs and the identification of general trends, and (iii) identify further research needs. The results of this analysis show that aerobic cometabolism can degrade a wide range of HAHs, including HAHs that were not previously tested such as chlorinated propanes, highly chlorinated ethanes and brominated methanes and ethanes. The degree of chlorine mineralization was very high for the chlorinated HAHs. Bromine mineralization was not determined for studies with brominated aliphatics. The examined research period led to the identification of novel growth substrates of potentially high interest. Decreasing performance of aerobic cometabolism were found with increasing chlorination, indicating the high potential of aerobic cometabolism in the presence of medium- and low-halogenated HAHs. Further research is needed for the AC of brominated aliphatic hydrocarbons, the potential for biofilm aerobic cometabolism processes, HAH-HAH mutual inhibition and the identification of the enzymes responsible for each aerobic cometabolism process. Lastly, some indications for a possible standardization of future kinetic studies of HAH aerobic cometabolism are provided. PMID:26874310

  16. Exploring mild enzymatic sustainable routes for the synthesis of bio-degradable aromatic-aliphatic oligoesters.

    Science.gov (United States)

    Pellis, Alessandro; Guarneri, Alice; Brandauer, Martin; Acero, Enrique Herrero; Peerlings, Henricus; Gardossi, Lucia; Guebitz, Georg M

    2016-05-01

    The application of Candida antarctica lipase B in enzyme-catalyzed synthesis of aromatic-aliphatic oligoesters is here reported. The aim of the present study is to systematically investigate the most favorable conditions for the enzyme catalyzed synthesis of aromatic-aliphatic oligomers using commercially available monomers. Reaction conditions and enzyme selectivity for polymerization of various commercially available monomers were considered using different inactivated/activated aromatic monomers combined with linear polyols ranging from C2 to C12 . The effect of various reaction solvents in enzymatic polymerization was assessed and toluene allowed to achieve the highest conversions for the reaction of dimethyl isophthalate with 1,4-butanediol and with 1,10-decanediol (88 and 87% monomer conversion respectively). Mw as high as 1512 Da was obtained from the reaction of dimethyl isophthalate with 1,10-decanediol. The obtained oligomers have potential applications as raw materials in personal and home care formulations, for the production of aliphatic-aromatic block co-polymers or can be further functionalized with various moieties for a subsequent photo- or radical polymerization.

  17. Preparation and characterization of biodegradable aliphatic-aromatic copolyesters/nano-SiO_2 hybrids via in situ melt polycondensation

    Institute of Scientific and Technical Information of China (English)

    Yan Zhang; Bing Tao Wang; Zheng Hong Guo; Jie Chen; Zheng Ping Fang

    2009-01-01

    In situ melt polycondensation was proposed to prepare biodegradable aliphatic-aromatic copolyesters/nano-SiO_2 hybrids based on terephthalic acid (TPA), poly(L-lactic acid) oligomer (OLLA), 1,4-butanediol (BDO) and nano-SiO_2. TEM and FT-IR characterizations confirmed that TPA, OLLA and BDO copolymerized to obtain biodegradable copolyesters, poly(butylene terephthalate-co-lactate) (PBTL), and the abundant hydroxyl groups on the surface of nano-SiO_2 provided potential sites for in situ grafting with the simultaneous resulted PBTL. The nano-SiO_2 particles were chemically wrapped with PBTL to form PBTL/nano-SiO2 hybrids. Due to the good dispersion and interfacial adhesion of nano-SiO_2 particles with the copolyester matrix, the tensile strength and the Young's modulus increased from 5.4 and 5.6 Mpa for neat PBTL to 16 and 390 Mpa for PBTL/nano-SiO_2 hybrids with 5 wt.% nano-SiO_2, respectively. The mechanical properties of PBTL/nano-SiO_2 hybrids were substantially improved.

  18. Synthesis and characterization of biodegradable aliphatic copolyesters with hydrophilic soft segments

    Directory of Open Access Journals (Sweden)

    JASNA DJONLAGIC

    2004-12-01

    Full Text Available In this study, the synthesis, structure and physical properties of two series of segmented poly(ester-ethers based on poly(butylene succinate and two different types of polyethers were investigated. The poly(ester-ethers were synthesized by transesterification reaction of dimethyl succinate, 1,4-butanediol and poly(ethylene oxide (PEO, Mn = 1000 g/mol in the first series, and poly(tetramethylene oxide (PTMO, Mn = 1000 g/mol in the second. The mass fraction of soft segments was varied between 10 and 50 mass. %. The effect of the introduction of two different polyether soft segments on the structure, thermal and rheological properties were investigated. The composition of the poly(ester-ethers, determined from their 1H-NMR spectra, showed that incorporation of soft polyether segments was successfully performed by the transesterification reaction in bulk. The molecular weight was estimated from solution viscosity measurements and complex dynamic viscosities. The thermal properties investigated by DSC indicated that the presence of soft segments lowers the melting and crystallization temperature of the hard phase, as well as the degree of crystallinity. Dynamical mechanical analysis was used to investigate the influence of composition on the rheological behavior of the segmented poly(ester-ethers. The results obtained from an enzymatic degradation test performed on some of the synthesized polymers showed that the biodegradability is enhanced with increasing hydrophilicity.

  19. Design, Synthesis and Characterisation of Novel Biodegradable Aliphatic Copolyesters- Poly(ethylene sebacate-co-butylene succinate and Poly(ethylene sebacate-co-butylene adipate

    Directory of Open Access Journals (Sweden)

    L. SOWBAGYALAKSHMI PRABHA

    2012-12-01

    Full Text Available Synthesis of novel aliphatic biodegradable copolyesters namely Poly (ethylene sebacate-co-butylene succinate and Poly (ethylene sebacate-co-butylene adipate were carried out using Poly (butylene Succinate, Poly (Butylene Adipate and Poly (Ethylene Sebacate in presence of Poly Phosphoric acid. Synthesis of Poly (Butylene Succinate, Poly (Butylene Adipate and Poly (Ethylene Sebacate were carried out using respective diols and diacids in presence of titanium tetrabutoxide as catalyst. Newly synthesized copolyesters were characterized by solubility studies, viscosity measurements, thermal analysis, IR Spectroscopy and Nuclear Magnetic Resonance Spectroscopy (1H-NMR and 13C-NMR. The characteristic peaks present in the homopolyesters were recorded in the copolymers as well. DSC analysis of the copolyesters showed multiple melting peaks, while increase of methylene units in the di-acid decreased the Tg.

  20. Controlled-release fertilizer prepared using a biodegradable aliphatic copolyester of poly(butylene succinate) and dimerized fatty acid.

    Science.gov (United States)

    Lubkowski, Krzysztof; Smorowska, Aleksandra; Grzmil, Barbara; Kozłowska, Agnieszka

    2015-03-18

    The preparation and characterization of a controlled-release multicomponent (NPK) fertilizer with the coating layer consisting of a biodegradable copolymer of poly(butylene succinate) and a butylene ester of dilinoleic acid (PBS/DLA) is reported. The morphology and structure of the resulting polymer-coated materials and the thickness of the covering layers were examined using X-ray diffraction and scanning electron microscopy coupled with energy dispersive X-ray analysis. The mechanical properties of these materials were determined with a strength-testing machine. Nutrient release was measured in water using spectrophotometry, potentiometry, and conductivity methods. The results of the nutrient release experiments from these polymer-coated materials were compared with the requirements for controlled-release fertilizers. A conceptual model is presented describing the mechanism of nutrient release from the materials prepared in this study. This model is based on the concentrations of mineral components inside the water-penetrated fertilizer granules, the diffusion properties of the nutrients in water, and a diffusion coefficient through the polymer layer. The experimental kinetic data on nutrient release were interpreted using the sigmoidal model equation developed in this study. PMID:25715823

  1. 酯交换法制备可生物降解脂肪族聚碳酸酯及其应用的研究进展%Progress in Synthesis of Biodegradable Aliphatic Polycarbonate by Transesterification

    Institute of Scientific and Technical Information of China (English)

    朱文祥; 李春成; 张栋; 肖耀南; 管国虎

    2011-01-01

    Aliphatic polycarbonates(APC)have attracted considerable attention as an important class of biodegradable polymers for their favorable biodegradability, biocompatibility and mechanical properties. APC are generally synthesized by the following four methods. (1)reaction of aliphatic diols with phosgene, (2) ring-opening polymerization of cyclic carbonates, (3) polymerization of epoxides with carbon dioxide,or(4)transesterification of dialkyl carbonates with aliphatic diols. Recently, there are lots of reports on synthesizing APC by methods(2)and(3),while there are not so many reports on method (4). This paper reviews the synthesis and application of APC,and the emphasis is placed on progress in synthesizing APC by transesterification.%脂肪族聚碳酸酯(APC)作为一类重要的可生物降解高分子材料,具有良好的生物降解性、生物相容性和物理机械性能,受到人们的广泛关注。APC的制备方法主要有光气法、开环聚合法、二氧化碳/环氧化物共聚法和酯交换法。近年来,有关开环聚合法和二氧化碳/环氧化物共聚法制备APC的研究越来越多,而酯交换法制备APC的研究相对较少。本文综述APC的合成方法和应用,并着重介绍酯交换法制备APC的研究进展。

  2. Biodegradability of unsaturated aliphatic polyesters prepared from fumaric acid%以反丁烯二酸合成的不饱和脂肪族聚酯的生物降解性研究

    Institute of Scientific and Technical Information of China (English)

    杨群; 陆大年; 崔进

    2013-01-01

    Unsaturated aliphatic polyesters and copolyesters were prepared from fumaric acid (FA) , dieth-ylene glycol (DEG) and 1,4-butanediol (BD) by melt poly condensation method. Enzymatic degradation was performed at 37 ℃ in phosphate buffer solution with porcine pancreas lipase, effect of structures, compositions and cross-linking degrees of carbon-carbon double bonds of polyesters on the biodegradability were discussed. The results indicated that, as the C=C double bond introduced into the backbone of solid polyesters, Tm value and crystallinity increased. The degradability of aliphatic polyesters by lipases depended strongly on their Tm values and crystallinity, the higher the Tm and crystallinity, the lower the degradability . The result also indicated that the thermal properties ( Tm value and - △Hm value) and crystallinity of polyesters increased after partially enzymatic degradation, the biodegradation of unsaturated aliphatic polyester became smaller after cross-linked, and the higher the cross-linking degree, the smaller the biodegradation.%以反丁烯二酸、一缩二乙二醇和1,4-丁二醇为原料,采用熔融缩聚法合成了不饱和脂肪族聚酯和共聚酯,在37℃下,用含有脂肪酶的磷酸缓冲溶液对聚酯的生物降解性进行了研究,讨论了聚酯结构、组成及C=C双键的交联度对生物降解性的影响.结果表明,对于粘稠液体状的聚酯,C=C双键的引入,没有明显的改变其生物降解性;对于固体状的聚酯,C=C双键引入后,熔点(Tm)和结晶度增加;聚酯部分降解后,其热力学性能(Tm、-△Hm)和结晶度都升高;对于交联后的聚酯,交联度越高,生物降解性越差.

  3. Research Progress in Biodegradation of Aliphatic Polyesters under Aquatic Environment%水生环境下脂肪族聚酯生物降解性能研究进展

    Institute of Scientific and Technical Information of China (English)

    孙炳新; 揣成智; 韩春阳; 郭迎; 冯叙桥

    2012-01-01

    以脂肪族聚酯在不同水生环境下的生物降解性能研究为出发点,概述了国内外在此领域的研究进展情况,通过分析发现,对于PBS,PCL,PLA和PPC等化学合成类脂肪族聚酯的降解性能的研究相当缺乏,对于这些生物降解材料降解性能的研究,尤其是在水生环境下的降解性能,还需要大量的试验来获取更多详实的基础数据。%Research progress in biodegradation of aliphatic polyesters in different aquatic environments was reviewed. Analysis of related information indicated that more researches need to be carried out so that the degra- dation of chemical synthetic aliphatic polyesters, such as PBS, PCL, PLA and PPC, can be understood. Therefore, researches in the future must stress on the degradation of these materials especially in aquatic environment in an effort to acquire reliable data.

  4. Microbial degradation of aliphatic and aliphatic-aromatic co-polyesters.

    Science.gov (United States)

    Shah, Aamer Ali; Kato, Satoshi; Shintani, Noboru; Kamini, Numbi Ramudu; Nakajima-Kambe, Toshiaki

    2014-04-01

    Biodegradable plastics (BPs) have attracted much attention since more than a decade because they can easily be degraded by microorganisms in the environment. The development of aliphatic-aromatic co-polyesters has combined excellent mechanical properties with biodegradability and an ideal replacement for the conventional nondegradable thermoplastics. The microorganisms degrading these polyesters are widely distributed in various environments. Although various aliphatic, aromatic, and aliphatic-aromatic co-polyester-degrading microorganisms and their enzymes have been studied and characterized, there are still many groups of microorganisms and enzymes with varying properties awaiting various applications. In this review, we have reported some new microorganisms and their enzymes which could degrade various aliphatic, aromatic, as well as aliphatic-aromatic co-polyesters like poly(butylene succinate) (PBS), poly(butylene succinate)-co-(butylene adipate) (PBSA), poly(ε-caprolactone) (PCL), poly(ethylene succinate) (PES), poly(L-lactic acid) (PLA), poly(3-hydroxybutyrate) and poly(3-hydoxybutyrate-co-3-hydroxyvalterate) (PHB/PHBV), poly(ethylene terephthalate) (PET), poly(butylene terephthalate) (PBT), poly(butylene adipate-co-terephthalate (PBAT), poly(butylene succinate-co-terephthalate) (PBST), and poly(butylene succinate/terephthalate/isophthalate)-co-(lactate) (PBSTIL). The mechanism of degradation of aliphatic as well as aliphatic-aromatic co-polyesters has also been discussed. The degradation ability of microorganisms against various polyesters might be useful for the treatment and recycling of biodegradable wastes or bioremediation of the polyester-contaminated environments. PMID:24522729

  5. Anaerobic digestion of aliphatic polyesters.

    Science.gov (United States)

    Šmejkalová, Pavla; Kužníková, Veronika; Merna, Jan; Hermanová, Soňa

    2016-01-01

    Anaerobic processes for the treatment of plastic materials waste represent versatile and effective approach in environmental protection and solid waste management. In this work, anaerobic biodegradability of model aliphatic polyesters, poly(L-lactic acid) (PLA), and poly(ɛ-caprolactone) (PCL), in the form of powder and melt-pressed films with varying molar mass, was studied. Biogas production was explored in batch laboratory trials at 55 ± 1°C under a nitrogen atmosphere. The inoculum used was thermophilic digested sludge (total solids concentration of 2.9%) from operating digesters at the Central Waste Water Treatment Plant in Prague, Czech Republic. Methanogenic biodegradation of PCLs typically yielded from 54 to 60% of the theoretical biogas yield. The biodegradability of PLAs achieved from 56 to 84% of the theoretical value. High biogas yield (up to 677 mL/g TS) with high methane content (more than 60%), comparable with conventionally processed materials, confirmed the potential of polyester samples for anaerobic treatment in the case of their exploitation in agriculture or as a packaging material in the food industry. PMID:27191559

  6. Absorbable and biodegradable polymers

    CERN Document Server

    Shalaby, Shalaby W

    2003-01-01

    INTRODUCTION NOTES: Absorbable/Biodegradable Polymers: Technology Evolution. DEVELOPMENT AND APPLICATIONOF NEW SYSTEMS: Segmented Copolyesters with Prolonged Strength Retention Profiles. Polyaxial Crystalline Fiber-Forming Copolyester. Polyethylene Glycol-Based Copolyesters. Cyanoacrylate-Based Systems as Tissue Adhesives. Chitosan-Based Systems. Hyaluronic Acid-Based Systems. DEVELOPMENTS IN PREPARATIVE, PROCESSING, AND EVALUATION METHODS: New Approaches to the Synthesis of Crystalline. Fiber-Forming Aliphatic Copolyesters. Advances in Morphological Development to Tailor the Performance of Me

  7. A review of plastic waste biodegradation.

    Science.gov (United States)

    Zheng, Ying; Yanful, Ernest K; Bassi, Amarjeet S

    2005-01-01

    With more and more plastics being employed in human lives and increasing pressure being placed on capacities available for plastic waste disposal, the need for biodegradable plastics and biodegradation of plastic wastes has assumed increasing importance in the last few years. This review looks at the technological advancement made in the development of more easily biodegradable plastics and the biodegradation of conventional plastics by microorganisms. Additives, such as pro-oxidants and starch, are applied in synthetic materials to modify and make plastics biodegradable. Recent research has shown that thermoplastics derived from polyolefins, traditionally considered resistant to biodegradation in ambient environment, are biodegraded following photo-degradation and chemical degradation. Thermoset plastics, such as aliphatic polyester and polyester polyurethane, are easily attacked by microorganisms directly because of the potential hydrolytic cleavage of ester or urethane bonds in their structures. Some microorganisms have been isolated to utilize polyurethane as a sole source of carbon and nitrogen source. Aliphatic-aromatic copolyesters have active commercial applications because of their good mechanical properties and biodegradability. Reviewing published and ongoing studies on plastic biodegradation, this paper attempts to make conclusions on potentially viable methods to reduce impacts of plastic waste on the environment. PMID:16419620

  8. Biodegradation of polyester. Polyester no bunkai sei

    Energy Technology Data Exchange (ETDEWEB)

    Tokiwa, Y. (Agency of Industrial Science and Technology, Tokyo (Japan). Fermentation Research Inst.)

    1991-09-10

    Penicillium sp. 14-3 and penicillium sp. 26-1 can degrade various kinds of polyester. The results of studies made on hydrolysis of polyester by enzyme, hydrolysis of polyester by various kinds of lipase, and degradation of ester type polyurethane by microbes and lipase are introduced. For the improvement of physical properties of aliphatic polyester, aromatic-aliphatic polyester copolymers (CPE) have been synthesized to study the biodegradability. Copolymer in which a number of polyamide (nylon) are alternately introduced (CPAE) to aliphatic polyester has been developed. The result of studies made on the degradability of a blended body of PCL and natural high polymer, and on the collapsibility by lipase of high polymer materials including aliphatic polyamide are introduced. 26 refs., 5 figs., 1 tab.

  9. Biodegradable Polymers

    Directory of Open Access Journals (Sweden)

    Isabelle Vroman

    2009-04-01

    Full Text Available Biodegradable materials are used in packaging, agriculture, medicine and other areas. In recent years there has been an increase in interest in biodegradable polymers. Two classes of biodegradable polymers can be distinguished: synthetic or natural polymers. There are polymers produced from feedstocks derived either from petroleum resources (non renewable resources or from biological resources (renewable resources. In general natural polymers offer fewer advantages than synthetic polymers. The following review presents an overview of the different biodegradable polymers that are currently being used and their properties, as well as new developments in their synthesis and applications.

  10. Guided desaturation of unactivated aliphatics

    Science.gov (United States)

    Voica, Ana-Florina; Mendoza, Abraham; Gutekunst, Will R.; Fraga, Jorge Otero; Baran, Phil S.

    2012-08-01

    The excision of hydrogen from an aliphatic carbon chain to produce an isolated olefin (desaturation) without overoxidation is one of the most impressive and powerful biosynthetic transformations for which there are no simple and mild laboratory substitutes. The versatility of olefins and the range of reactions they undergo are unsurpassed in functional group space. Thus, the conversion of a relatively inert aliphatic system into its unsaturated counterpart could open new possibilities in retrosynthesis. In this article, the invention of a directing group to achieve such a transformation under mild, operationally simple, metal-free conditions is outlined. This ‘portable desaturase’ (TzoCl) is a bench-stable, commercial entity (Aldrich, catalogue number L510092) that is facile to install on alcohol and amine functionalities to ultimately effect remote desaturation, while leaving behind a synthetically useful tosyl group.

  11. Aliphatic hydrocarbons of the fungi.

    Science.gov (United States)

    Weete, J. D.

    1972-01-01

    Review of studies of aliphatic hydrocarbons which have been recently detected in the spores of phytopathogenic fungi, and are found to be structurally very similar to the alkanes of higher plants. It appears that the hydrocarbon components of the few mycelial and yeast forms reported resemble the distribution found in bacteria. The occurence and distribution of these compounds in the fungi is discussed. Suggested functional roles of fungal spore alkanes are presented.

  12. Combinatorics of aliphatic amino acids.

    Science.gov (United States)

    Grützmann, Konrad; Böcker, Sebastian; Schuster, Stefan

    2011-01-01

    This study combines biology and mathematics, showing that a relatively simple question from molecular biology can lead to complicated mathematics. The question is how to calculate the number of theoretically possible aliphatic amino acids as a function of the number of carbon atoms in the side chain. The presented calculation is based on earlier results from theoretical chemistry concerning alkyl compounds. Mathematical properties of this number series are highlighted. We discuss which of the theoretically possible structures really occur in living organisms, such as leucine and isoleucine with a chain length of four. This is done both for a strict definition of aliphatic amino acids only involving carbon and hydrogen atoms in their side chain and for a less strict definition allowing sulphur, nitrogen and oxygen atoms. While the main focus is on proteinogenic amino acids, we also give several examples of non-proteinogenic aliphatic amino acids, playing a role, for instance, in signalling. The results are in agreement with a general phenomenon found in biology: Usually, only a small number of molecules are chosen as building blocks to assemble an inconceivable number of different macromolecules as proteins. Thus, natural biological complexity arises from the multifarious combination of building blocks.

  13. Biodegradation of lignin by Agaricus Bisporus

    Energy Technology Data Exchange (ETDEWEB)

    Vane, C.H.; Abbott, G.D.; Head, I.M. [Univ. of Newcastle upon Tyne (United Kingdom)

    1996-12-31

    The lignolytic activity of Agaricus bisporus will be addressed in this paper. Sound and fungally degraded lignins were characterized by Pyrolysis-Gas Chromatography-Mass Spectrometry (Py-GC-MS), Fourier Transform Infrared Spectroscopy (FnR) and elemental analysis. Fungally degraded lignins displayed increased wt%N, wt%H and wt%O content and decreased wt%C content The FTIR spectrum of decayed lignin showed an increase in the relative intensity of absorption bands assigned to carbonyl and carboxyl functional groups located on the aliphatic side chain and a decrease in absorption bands assigned to aromatic skeletal vibration modes. Semiquantitative Py-GC-MS revealed an 82% decrease in lignin derived pyrolysis products upon biodegradation. No significant increase in pyrolysis products with an oxygenated aliphatic side chain were detected in the fungally degraded lignin however shortening of the aliphatic side chain via cleavage at the {alpha}, {beta} and {gamma} positions was observed.

  14. Bacterial isolates degrading aliphatic polycarbonates.

    Science.gov (United States)

    Suyama, T; Hosoya, H; Tokiwa, Y

    1998-04-15

    Bacteria that degrade an aliphatic polycarbonate, poly(hexamethylene carbonate), were isolated from river water in Ibaraki. Prefecture, Japan, after enrichment in liquid medium containing poly(hexamethylene carbonate) suspensions as carbon source, and dilution to single cells. Four of the strains, 35L, WFF52, 61A and 61B2, degraded poly(hexamethylene carbonate) on agar plate containing suspended poly(hexamethylene carbonate). Degradation of poly(hexamethylene carbonate) was confirmed by gel permeation chromatography. Besides poly(hexamethylene carbonate), the strains were found to degrade poly(tetramethylene carbonate). The strains were characterized morphologically, physiologically, and by 16S rDNA sequence analysis. Strains 35L and WFF52 were tentatively identified as Pseudomonas sp. and Variovorax sp., respectively, while strains 61A and 61B2 constitute an unidentified branch within the beta subclass of the Proteobacteria.

  15. Molecular Design of Synthetic Biodegradable Polymers as Cell Scaffold Materials

    Institute of Scientific and Technical Information of China (English)

    WANG Shen-guo; WAN Yu-qing; CAI Qing; HE Bin; CHEN Wen-na

    2004-01-01

    Poly(lactic acid) and its copolymers are regarded as the most useful biomaterials. The good biocompatibility, biodegradability and mechanical properties of them make the synthetic biodegradable polymers have primary application to tissue engineering. The advantages and disadvantages of the synthetic biodegradable polymers as cell scaffold materials are evaluated. This article reviews the modification of polylactide-family aliphatic polymers to improve the cell affinity when the polymers are used as cell scaffolds. We have developed four main approaches: to modify polyester cell scaffolds in combination of plasma treating and collagen coating; to introduce hydrophilic segments into aliphatic polyester backbones; to introduce pendant functional groups into polyester chains; to modify polyester with dextran. The results of the cell cultures prove that the approaches mentioned above have improved the cell affinity of the polyesters and have modulated cell function such as adhesion, proliferation and migration.

  16. Biodegradable compounds: Rheological, mechanical and thermal properties

    Science.gov (United States)

    Nobile, Maria Rossella; Lucia, G.; Santella, M.; Malinconico, M.; Cerruti, P.; Pantani, R.

    2015-12-01

    Recently great attention from industry has been focused on biodegradable polyesters derived from renewable resources. In particular, PLA has attracted great interest due to its high strength and high modulus and a good biocompatibility, however its brittleness and low heat distortion temperature (HDT) restrict its wide application. On the other hand, Poly(butylene succinate) (PBS) is a biodegradable polymer with a low tensile modulus but characterized by a high flexibility, excellent impact strength, good thermal and chemical resistance. In this work the two aliphatic biodegradable polyesters PBS and PLA were selected with the aim to obtain a biodegradable material for the industry of plastic cups and plates. PBS was also blended with a thermoplastic starch. Talc was also added to the compounds because of its low cost and its effectiveness in increasing the modulus and the HDT of polymers. The compounds were obtained by melt compounding in a single screw extruder and the rheological, mechanical and thermal properties were investigated. The properties of the two compounds were compared and it was found that the values of the tensile modulus and elongation at break measured for the PBS/PLA/Talc compound make it interesting for the production of disposable plates and cups. In terms of thermal resistance the compounds have HDTs high enough to contain hot food or beverages. The PLA/PBS/Talc compound can be, then, considered as biodegradable substitute for polystyrene for the production of disposable plates and cups for hot food and beverages.

  17. Anaerobic biodegradability of macropollutants

    DEFF Research Database (Denmark)

    Angelidaki, Irini

    2002-01-01

    A variety of test procedures for determination of anaerobic biodegradability has been reported. This paper reviews the methods developed for determination of anaerobic biodegradability of macro-pollutants. Anaerobic biodegradability of micro-pollutants is not included. Furthermore, factors import...

  18. Biodegradation and bioremediation

    DEFF Research Database (Denmark)

    Albrechtsen, H.-J.

    1996-01-01

    Anmeldelse af Alexander,M.: Biodegradation and bioremediation. Academic Press, Sandiego, USA, 1994......Anmeldelse af Alexander,M.: Biodegradation and bioremediation. Academic Press, Sandiego, USA, 1994...

  19. Polyester-Based (Biodegradable Polymers as Environmentally Friendly Materials for Sustainable Development

    Directory of Open Access Journals (Sweden)

    Joanna Rydz

    2014-12-01

    Full Text Available This review focuses on the polyesters such as polylactide and polyhydroxyalkonoates, as well as polyamides produced from renewable resources, which are currently among the most promising (biodegradable polymers. Synthetic pathways, favourable properties and utilisation (most important applications of these attractive polymer families are outlined. Environmental impact and in particular (biodegradation of aliphatic polyesters, polyamides and related copolymer structures are described in view of the potential applications in various fields.

  20. Polyester-Based (Bio)degradable Polymers as Environmentally Friendly Materials for Sustainable Development

    OpenAIRE

    Joanna Rydz; Wanda Sikorska; Mariya Kyulavska; Darinka Christova

    2014-01-01

    This review focuses on the polyesters such as polylactide and polyhydroxyalkonoates, as well as polyamides produced from renewable resources, which are currently among the most promising (bio)degradable polymers. Synthetic pathways, favourable properties and utilisation (most important applications) of these attractive polymer families are outlined. Environmental impact and in particular (bio)degradation of aliphatic polyesters, polyamides and related copolymer structures are described in vie...

  1. Biodegradation of diesel/biodiesel blends in saturated sand microcosms

    DEFF Research Database (Denmark)

    Lisiecki, Piotr; Chrzanowski, Łukasz; Szulc, Alicja;

    2014-01-01

    The aim of the study was to evaluate the biodegradation extent of both aromatic and aliphatic hydrocarbon fractions in saturated sandy microcosm spiked with diesel/biodiesel blends (D, B10, B20, B30, B40, B50, B60, B70, B80, B90 and B100, where D is commercial petroleum diesel fuel and B is comme...... of biodiesel, regardless of the concentration used. This observation leads to the conclusion that blending with biodiesel does not impact the long-term biodegradation of specific diesel oil fractions. © 2013 Elsevier Ltd. All rights reserved....

  2. Interaction of gaseous aromatic and aliphatic compounds in thermophilic biofilters.

    Science.gov (United States)

    Hu, Qing-yuan; Wang, Can

    2015-12-30

    Two thermophilic biofilters were applied in treating a mixture of gaseous aromatic (benzene) and aliphatic compounds (hexane) to evaluate the interaction of the compounds. The performance of the biofilters was investigated in terms of removal efficiencies, elimination capacity, kinetic analysis, interaction indices, and microbial metabolic characteristics. Results showed that the removal performance of benzene was unaffected by the addition of hexane. The removal efficiencies of benzene were maintained at approximately 80% and the biodegradation rate constant was maintained at 120 h(-1). However, the removal efficiencies of hexane decreased significantly from 60% to 20% and the biodegradation rate constant exhibited a distinct decrease from 93.59 h(-1) to 56.32 h(-1). The interaction index of benzene with the addition of hexane was -0.029, which indicated that hexane had little effect on the degradation of benzene. By contrast, the interaction index of hexane by benzene was -0.557, which showed that benzene inhibited the degradation of hexane significantly. Similar conclusions were obtained about the substrate utilization. Moreover, the utilization degree of carbon sources and the microbial metabolic activities in the biofilter treating hexane were significantly improved with the addition of benzene, whereas the addition of hexane had a slight effect on the microbial communities in the biofilter treating benzene. Conclusions could be obtained that when mixtures of benzene and hexane were treated using biofilters, the degradation of benzene, which was more easily degradable, was dominant and unaffected; whereas the degradation of hexane, which was less easily degradable, was inhibited because of the changing of microbes.

  3. Study of the electron beam irradiation effect on some properties of aromatic aliphatic copolyester films

    International Nuclear Information System (INIS)

    Biodegradable and green plastics are the new tendency in the world. The effect of the electron beam irradiation in aromatic aliphatic copolyester and the blend with corn starch films (EcoflexR and EcobrasR) were studied by tensile strength at break, elongation at break, Scanning Electronic Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FT-IR), Differential Scanning Calorimetry (DSC), crosslinking degree and biodegradability. The measurements in both, the machine direction and the transverse direction were made for mechanical tests. It was found that, the electron irradiation caused an increase in the strength at break of the blend with corn starch film, when doses of up to 10 kGy were applied. A significant decrease of the elongation at break of the blend with corn starch was observed at doses of 10 kGy and 40 kGy. It was not found important change in tensile properties for aromatic aliphatic copolyester. Structural changes of the samples (crosslinking or degradation) by SEM were not observed. The FT-IR identified the characteristic peaks of each involved functional group (copolyester and corn starch). However, it was not found bands of oxidation of the samples. In the DSC, changes in the melting temperature of the irradiated EcoflexR and EcobrasR samples, was not identified when compared with the samples of reference. However, it was verified a reduction in the melting enthalpy of the EcobrasR samples after irradiation. The EcobrasR material presented crosslinking, when submitted to doses of 10 kGy and 40 kGy. The EcoflexR material did not present crosslinking when submitted to these doses. The biodegradability of the materials was evaluated by two methods of test: soil simulated and enzymatic. In both methods, the irradiated samples presented faster biodegradation than the references not irradiated. (author)

  4. Liquid-crystalline aromatic-aliphatic copolyester bioresorbable polymers.

    Science.gov (United States)

    de Oca, Horacio Montes; Wilson, Joanne E; Penrose, Andrew; Langton, David M; Dagger, Anthony C; Anderson, Melissa; Farrar, David F; Lovell, Christopher S; Ries, Michael E; Ward, Ian M; Wilson, Andrew D; Cowling, Stephen J; Saez, Isabel M; Goodby, John W

    2010-10-01

    The synthesis and characterisation of a series of liquid-crystalline aromatic-aliphatic copolyesters are presented. Differential scanning calorimetry showed these polymers have a glass transition temperature in the range 72 degrees C-116 degrees C. Polarised optical microscopy showed each polymer exhibits a nematic mesophase on heating to the molten state at temperatures below 165 degrees C. Melt processing is demonstrated by the production of injection moulded and compression moulded specimens with Young's modulus of 5.7 +/- 0.3 GPa and 2.3 +/- 0.3 GPa, respectively. Wide-angle X-ray scattering data showed molecular orientation is responsible for the increase of mechanical properties along the injection direction. Degradation studies in the temperature range 37 degrees C-80 degrees C are presented for one polymer of this series and a kinetic constant of 0.002 days(-1) is obtained at 37 degrees C assuming a first order reaction. The activation energy (83.4 kJ mol(-1)) is obtained following the Arrhenius analysis of degradation, showing degradation of this material is less temperature sensitive compared with other commercially available biodegradable polyesters. In vitro and in vivo biocompatibility data are presented and it is shown the unique combination of degradative, mechanical and biological properties of these polymers may represent in the future an alternative for medical device manufacturers.

  5. Electrospun aliphatic polycarbonates as tailored tissue scaffold materials.

    Science.gov (United States)

    Welle, Alexander; Kröger, Mario; Döring, Manfred; Niederer, Kerstin; Pindel, Elvira; Chronakis, Ioannis S

    2007-04-01

    Two different aliphatic polycarbonates were synthesised from CO(2) and the respective epoxides. Poly(propyl carbonate) (PPC) was prepared by heterogeneous catalysis with zinc glutarate. Poly(cyclohexyl carbonate) (PCHC) was prepared via living copolymerisation homogeneously catalysed by a 3-amino-2-cyanoimidoacrylate zinc acetate complex and subjected to electrospinning. The obtained nanofibres had a well-defined morphology free of beads along the fibres and with slightly porous structures on their surface. Subsequently, low-power deep UV irradiations, previously applied for photochemical surface modifications of two-dimensional and three-dimensional scaffolds from biostable polymers, were performed. Here, an effect on surface and bulk properties of PPC nanofibres was observed. Surface modifications of both polymers affected plasma protein adsorption. Photochemical bulk modifications observed for the first time on PPC nanofibres are indicating the possibility of spatial control of biodegradation rates, hence allow for control of the progression of host/implant interactions in vivo. In particular PPC was used for cell culture of L929 fibroblasts and primary rat hepatocytes. Even delicate primary cells showed good adhesion to the scaffolds and high viability.

  6. CCN activity of aliphatic amine secondary aerosol

    Science.gov (United States)

    Tang, X.; Price, D.; Praske, E.; Vu, D.; Purvis-Roberts, K.; Silva, P. J.; Cocker, D. R., III; Asa-Awuku, A.

    2014-01-01

    Aliphatic amines can form secondary aerosol via oxidation with atmospheric radicals (e.g. hydroxyl radical and nitrate radical). The particle composition can contain both secondary organic aerosol (SOA) and inorganic salts. The fraction of organic to inorganic materials in the particulate phase influences aerosol hygroscopicity and cloud condensation nuclei (CCN) activity. SOA formed from trimethylamine (TMA) and butylamine (BA) reactions with hydroxyl radical (OH) is composed of organic material of low hygroscopicity (single hygroscopicity parameter, κ ≤ 0.25). Secondary aerosol formed from the tertiary aliphatic amine (TMA) with N2O5 (source of nitrate radical, NO3), contains less volatile compounds than the primary aliphatic amine (BA) aerosol. TMA + N2O5 form semi-volatile organics in low RH conditions that have κ ~ 0.20, indicative of slightly soluble organic material. As RH increases, several inorganic amine salts are formed as a result of acid-base reactions. The CCN activity of the humid TMA-N2O5 aerosol obeys Zdanovskii, Stokes, and Robinson (ZSR) ideal mixing rules. Higher CCN activity (κ > 0.3) was also observed for humid BA+N2O5 aerosols compared with dry aerosol (κ ~ 0.2), as a result of the formation of inorganic salts such as NH4NO3 and butylamine nitrate (C4H11N · HNO3). Compared with TMA, BA+N2O5 reactions produce more volatile aerosols. The BA+N2O5 aerosol products under humid experiments were found to be very sensitive to the temperature within the stream-wise continuous flow thermal gradient CCN counter. The CCN counter, when set above a 21 °C temperature difference, evaporates BA+N2O5 aerosol formed at RH ≥ 30%; κ ranges from 0.4 to 0.7 and is dependent on the instrument supersaturation (ss) settings. The aerosol behaves non-ideally, hence simple ZSR rules cannot be applied to the CCN results from the primary aliphatic amine system. Overall, aliphatic amine aerosol systems κ ranges from 0.2 CCN activity. Thermal gradient CCN

  7. CCN activity of aliphatic amine secondary aerosol

    Directory of Open Access Journals (Sweden)

    X. Tang

    2014-01-01

    Full Text Available Aliphatic amines can form secondary aerosol via oxidation with atmospheric radicals (e.g. hydroxyl radical and nitrate radical. The particle composition can contain both secondary organic aerosol (SOA and inorganic salts. The fraction of organic to inorganic materials in the particulate phase influences aerosol hygroscopicity and cloud condensation nuclei (CCN activity. SOA formed from trimethylamine (TMA and butylamine (BA reactions with hydroxyl radical (OH is composed of organic material of low hygroscopicity (single hygroscopicity parameter, κ ≤ 0.25. Secondary aerosol formed from the tertiary aliphatic amine (TMA with N2O5 (source of nitrate radical, NO3, contains less volatile compounds than the primary aliphatic amine (BA aerosol. TMA + N2O5 form semi-volatile organics in low RH conditions that have κ ~ 0.20, indicative of slightly soluble organic material. As RH increases, several inorganic amine salts are formed as a result of acid-base reactions. The CCN activity of the humid TMA-N2O5 aerosol obeys Zdanovskii, Stokes, and Robinson (ZSR ideal mixing rules. Higher CCN activity (κ > 0.3 was also observed for humid BA+N2O5 aerosols compared with dry aerosol (κ ~ 0.2, as a result of the formation of inorganic salts such as NH4NO3 and butylamine nitrate (C4H11N · HNO3. Compared with TMA, BA+N2O5 reactions produce more volatile aerosols. The BA+N2O5 aerosol products under humid experiments were found to be very sensitive to the temperature within the stream-wise continuous flow thermal gradient CCN counter. The CCN counter, when set above a 21 °C temperature difference, evaporates BA+N2O5 aerosol formed at RH ≥ 30%; κ ranges from 0.4 to 0.7 and is dependent on the instrument supersaturation (ss settings. The aerosol behaves non-ideally, hence simple ZSR rules cannot be applied to the CCN results from the primary aliphatic amine system. Overall, aliphatic amine aerosol systems κ ranges from 0.2 < κ < 0.7. This work indicates that

  8. A biocatalytic approach towards sustainable furanic-aliphatic polyesters

    NARCIS (Netherlands)

    Jiang, Yi; Woortman, Albert J. J.; van Ekenstein, Gert O. R. Alberda; Loos, Katja

    2015-01-01

    An eco-friendly approach towards furanic-aliphatic polyesters as sustainable alternatives to aromatic-aliphatic polyesters is presented. In this approach, biobased dimethyl 2,5-furandicarboxylate (DMFDCA) is polymerized with various (potentially) renewable aliphatic diols via Candida antarctica Lipa

  9. Photoluminescence of Diamondoid Crystals

    Energy Technology Data Exchange (ETDEWEB)

    Clay, William; /Stanford U., Phys. Dept. /Stanford U., Appl. Phys. Dept. /Stanford U., Geballe Lab.; Sasagawa, Takao; Iwasa, Akio; /TIT, Nagatsuta; Liu, Zhi; /LBNL, ALS; Dahl, Jeremy E.; /Stanford U., Phys. Dept. /Stanford U., Appl. Phys. Dept. /Stanford U., Geballe Lab.; Carlson, Robert M.K.; /Molecular Diamond Technologies, Chevron Technology Ventures; Kelly, Michael; Melos, Nicholas; /Stanford U., Phys. Dept. /Stanford U., Appl. Phys. Dept. /Stanford U., Geballe Lab.; Shen, Zhi-Xun; /Stanford U., Phys. Dept. /Stanford U., Appl. Phys. Dept. /Stanford U., Geballe Lab. /SIMES, Stanford

    2012-04-03

    The photoluminescence of diamondoids in the solid state is examined. All of the diamondoids are found to photoluminesce readily with initial excitation wavelengths ranging from 233 nm to 240 nm (5.3 eV). These excitation energies are more than 1 eV lower than any previously studied saturated hydrocarbon material. The emission is found to be heavily shifted from the absorption, with emission wavelengths of roughly 295 nm (4.2 eV) in all cases. In the dissolved state, however, no uorescence is observed for excitation wavelengths as short as 200 nm. We also discuss predictions and measurements of the quantum yield. Our predictions indicate that the maximum yield may be as high as 25%. Our measurement of one species, diamantane, gives a yield of 11%, the highest ever reported for a saturated hydrocarbon, even though it was likely not at the optimal excitation wavelength.

  10. Proceedings of biodegradation

    International Nuclear Information System (INIS)

    This book contains the proceedings of Biodegradation. Topics include:biodegradation using the tools of biotechnology, basic science aspects of biodegradation, the physiological characteristics of microorganisms, the use of selective techniques that enhance the process of microbial evolution of biodegradative genes in nature, the genetic characteristics of microorganisms allowing them to biodegrade both natural and synthetic toxic chemicals, the molecular techniques that allow selective assembly of genetic segments form a variety of bacterial strains to a single strain, and methods needed to advance biodegradation research as well as the high-priority chemical problems important to the Department of Defense or to the chemical industry

  11. Elastic Compositions Based on Polyurethane/ Aliphatic Polyesters

    International Nuclear Information System (INIS)

    Aliphatic polyesters were prepared by melt condensation reaction of a dicarboxylic acid such as adipic and sebacic with different types of diol compounds in 1: 1.1 molar ratio. Ethylene glycol, di-, trio, tetra ethylene glycol and poly( ethylene glycol) with different molecular weights 1000, 4000, 6000 as well as the prepared hydroxy natural rubber were used as diol compounds. Polyurethane, with NCO/OH ratio equal 4, was synthesized from the reaction of toluene diisocyanate with poly(ethylene glycol) 1 000. The prepared polyurethane was mixed with different weight percentages of the prepared aliphatic polyesters. The film samples were tested mechanically, electrically and chemically. The results show that the weight percentage 10% of the added polyadipate or poly sebacate glycols improves flexibility, electrical volume resistivity, dielectric constant and dielectric loss of unmodified rigid polyurethane film sample as well as reduces its swelling by aromatic solvents. All the above mentioned properties improve by increasing the hydrocarbon chain length of the glycol portion in the glycol used and the number of methylene in the aliphatic dicarboxylic acid. Compositions based on hydroxy natural rubber impart better properties than those based on ethylene glycols

  12. Sources and distribution of aliphatic and polyaromatic hydrocarbons in coastal sediments from the Ushuaia Bay (Tierra del Fuego, Patagonia, Argentina).

    Science.gov (United States)

    Commendatore, Marta G; Nievas, Marina L; Amin, Oscar; Esteves, José L

    2012-03-01

    The environmental quality of Ushuaia Bay, located at the southernmost tip of South America, is affected by the anthropogenic pressure of Ushuaia city. In this study, levels and sources of hydrocarbons in coastal sediments were assessed. Aliphatic hydrocarbon fractions ranged between 5.5 and 1185.3 μg/g dry weight and PAHs from not detected to 360 ng/g. Aliphatic diagnostic indices, the nalkanes homologous series occurrence, Aliphatic Unresolved Complex Mixtures (AliUCMs), and pristane and phytane isoprenoids indicated a petrogenic input. Some sites showed biogenic features masked by the anthropogenic signature. Particularly in port areas biodegradation processes were evident. PAH ratios showed a mixture of petrogenic and pyrogenic sources. Aliphatic and aromatic UCMs were strongly correlated, reflecting chronic pollution. Three areas were distinguished inside the bay: (1) east, with low hydrocarbons impact; (2) central, where hydrocarbons accumulation was related to source proximity and sediment characteristics; (3) south-west, where sediment characteristics and current circulation favour hydrocarbons accumulation. PMID:22189069

  13. Biodegradation reduces magnetization in oil bearing rocks: magnetization results of a combined chemical and magnetic study

    Science.gov (United States)

    Emmerton, S.; Muxworthy, A. R.; Sephton, M. A.; Williams, W.

    2012-12-01

    A relationship between hydrocarbons and their magnetic signatures has been alluded to for decades but this is the first study to combine geochemical and magnetic data. We report an extended study that identifies a definitive connection between magnetic mineralogy and biodegradation within oil-bearing rocks. Samples from Colombia, Canada Indonesia and the UK were collected and magnetically characterized. A negative linear regression in log space between magnetic susceptibility and the percentage of extractable organic matter was observed for individual reservoirs. To determine if this relationship is due to the activity of bacteria or migration of the oil, the percentage of oil components; aliphatic, aromatics, polars and resins and the biodegradation state of the samples were compared to the magnetic susceptibility and magnetic mineralogy of the samples. Geochemical biomarker data revealed that all oil samples were derived from mature type-II kerogen, which was deposited in oxygen-poor environments allowing for an investigation into biodegradation variations. Biodegradation is the decrease of oil quality through the conversion of aliphatic hydrocarbons to polar constituents mainly through the activity of bacteria. A distinct decrease in magnetic susceptibility was correlated to decreasing oil quality (loss of aliphatic hydrocarbons, more biodegraded), which cannot be rejected at 99% confidence. Further magnetic characterization revealed that the high quality, low biodegradation oils from Colombia have a higher magnetic susceptibility (10-3-10-4 m3kg-1) and are dominated by pseudo-single domain grains of magnetite. The lower quality oils i.e., the UK, Canadian and Indonesian samples, displayed decreased magnetic susceptibility (10-5-10-6 m3kg-1) and pseudo-single domain to multidomain grains of magnetite and hematite. Magnetite and pyrrhotite framboidal material were found in all but the Canadian samples. Therefore, with decreasing oil quality there is a progressive

  14. A review of material properties of biodegradable and bioresorbable polymers and devices for GTR and GBR applications.

    Science.gov (United States)

    Hutmacher, D; Hürzeler, M B; Schliephake, H

    1996-01-01

    Use of bioresorbable and biodegradable materials for guided tissue and guided bone regeneration is under intense investigation and is being tested in clinical trials. This study presents a basic overview of material properties of bioresorbable and biodegradable polymers and devices for guided tissue and guided bone regeneration treatment. Collagens and aliphatic polyesters, such as poly(glycolic acid), poly(lactic acid), and poly(epsilon-caprolactone), are discussed, as well as biocompatibility, mechanical properties, and sterilization. PMID:8908867

  15. Nanomembranes and Nanofibers from Biodegradable Conducting Polymers

    Directory of Open Access Journals (Sweden)

    Jordi Puiggalí

    2013-09-01

    Full Text Available This review provides a current status report of the field concerning preparation of fibrous mats based on biodegradable (e.g., aliphatic polyesters such as polylactide or polycaprolactone and conducting polymers (e.g., polyaniline, polypirrole or polythiophenes. These materials have potential biomedical applications (e.g., tissue engineering or drug delivery systems and can be combined to get free-standing nanomembranes and nanofibers that retain the better properties of their corresponding individual components. Systems based on biodegradable and conducting polymers constitute nowadays one of the most promising solutions to develop advanced materials enable to cover aspects like local stimulation of desired tissue, time controlled drug release and stimulation of either the proliferation or differentiation of various cell types. The first sections of the review are focused on a general overview of conducting and biodegradable polymers most usually employed and the explanation of the most suitable techniques for preparing nanofibers and nanomembranes (i.e., electrospinning and spin coating. Following sections are organized according to the base conducting polymer (e.g., Sections 4–6 describe hybrid systems having aniline, pyrrole and thiophene units, respectively. Each one of these sections includes specific subsections dealing with applications in a nanofiber or nanomembrane form. Finally, miscellaneous systems and concluding remarks are given in the two last sections.

  16. Photoluminescence of a Plasmonic Molecule.

    Science.gov (United States)

    Huang, Da; Byers, Chad P; Wang, Lin-Yung; Hoggard, Anneli; Hoener, Ben; Dominguez-Medina, Sergio; Chen, Sishan; Chang, Wei-Shun; Landes, Christy F; Link, Stephan

    2015-07-28

    Photoluminescent Au nanoparticles are appealing for biosensing and bioimaging applications because of their non-photobleaching and non-photoblinking emission. The mechanism of one-photon photoluminescence from plasmonic nanostructures is still heavily debated though. Here, we report on the one-photon photoluminescence of strongly coupled 50 nm Au nanosphere dimers, the simplest plasmonic molecule. We observe emission from coupled plasmonic modes as revealed by single-particle photoluminescence spectra in comparison to correlated dark-field scattering spectroscopy. The photoluminescence quantum yield of the dimers is found to be surprisingly similar to the constituent monomers, suggesting that the increased local electric field of the dimer plays a minor role, in contradiction to several proposed mechanisms. Aided by electromagnetic simulations of scattering and absorption spectra, we conclude that our data are instead consistent with a multistep mechanism that involves the emission due to radiative decay of surface plasmons generated from excited electron-hole pairs following interband absorption. PMID:26165983

  17. 脂肪族聚碳酸酯及其在医学中的应用%Progress of Aliphatic Polycarbonates and their Applications in the Biomedical Field

    Institute of Scientific and Technical Information of China (English)

    周瑜; 刘芝兰; 陈红祥

    2011-01-01

    During the past decade,aliphatic polycarbonates have been widely studied and used in the biomedical field,because they are biocompatible,biodegradable and able to functionalization.In this article,combining with the authors' work and referring to the research status about biodegradable aliphatic polycarbonates at home and abroad,aliphatic polycarbonates were sorted according to the structure of polymer chains and also introduced briefly.Their synthetic methods and applications in the biomedical field were reviewed.In addition,the future development of aliphatic polycarbonates was also put forward.%脂肪族聚碳酸酯具有优良的生物降解性、生物相容性和可功能化性等特点,近十几年来在生物医学领域得到了迅速发展。结合本实验室对生物可降解脂肪族聚碳酸酯的研究工作以及国内外研究现状,根据高分子链的几何形状对脂肪族聚碳酸酯进行了分类介绍,综述了它们的合成方法及其在生物医学领域中的应用,同时展望了脂肪族聚碳酸酯的未来发展趋势。

  18. Biodegradation of microbial and synthetic polyesters by fungi.

    Science.gov (United States)

    Kim, D Y; Rhee, Y H

    2003-05-01

    A variety of biodegradable polyesters have been developed in order to obtain useful biomaterials and to reduce the impact of environmental pollution caused by the large-scale accumulation of non-degradable waste plastics. Polyhydroxyalkanoates, poly(epsilon-caprolactone), poly( l-lactide), and both aliphatic and aromatic polyalkylene dicarboxylic acids are examples of biodegradable polyesters. In general, most aliphatic polyesters are readily mineralized by a number of aerobic and anaerobic microorganisms that are widely distributed in nature. However, aromatic polyesters are more resistant to microbial attack than aliphatic polyesters. The fungal biomass in soils generally exceeds the bacterial biomass and thus it is likely that fungi may play a considerable role in degrading polyesters, just as they predominantly perform the decomposition of organic matter in the soil ecosystem. However, in contrast to bacterial polyester degradation, which has been extensively investigated, the microbiological and environmental aspects of fungal degradation of polyesters are unclear. This review reports recent advances in our knowledge of the fungal degradation of microbial and synthetic polyesters and discusses the ecological importance and contribution of fungi in the biological recycling of waste polymeric materials in the biosphere. PMID:12743758

  19. Effects of halogenated aromatics/aliphatics and nitrogen(N)-heterocyclic aromatics on estimating the persistence of future pharmaceutical compounds using a modified QSAR model.

    Science.gov (United States)

    Lim, Seung Joo; Fox, Peter

    2014-02-01

    The effects of halogenated aromatics/aliphatics and nitrogen(N)-heterocyclic aromatics on estimating the persistence of future pharmaceutical compounds were investigated using a modified half life equation. The potential future pharmaceutical compounds investigated were approximately 2000 pharmaceutical drugs currently undergoing the United States Food and Drug Administration (US FDA) testing. EPI Suite (BIOWIN) model estimates the fates of compounds based on the biodegradability under aerobic conditions. While BIOWIN considered the biodegradability of a compound only, the half life equation used in this study was modified by biodegradability, sorption and cometabolic oxidation. It was possible that the potential future pharmaceutical compounds were more accurately estimated using the modified half life equation. The modified half life equation considered sorption and cometabolic oxidation of halogenated aromatic/aliphatics and nitrogen(N)-heterocyclic aromatics in the sub-surface, while EPI Suite (BIOWIN) did not. Halogenated aliphatics in chemicals were more persistent than halogenated aromatics in the sub-surface. In addition, in the sub-surface environment, the fates of organic chemicals were much more affected by halogenation in chemicals than by nitrogen(N)-heterocyclic aromatics.

  20. Corrosion inhibition of brass by aliphatic amines

    International Nuclear Information System (INIS)

    Aliphatic amines hexylamine (HCA), octylamine (OCA) and decylamine (DCA) have been used as corrosion inhibitors for (70/30) brass in 0.I M HCIO4. The inhibitor efficiency (%P) calculated using weight loss, Tafel extrapolation, linear polarization and impedance methods was found to be in the order DCA> OCA> HCA. These adsorb on brass surface following bockris-swinkels' isotherm. DCA, OCA and HCA displaced 4, 3 and 2 molecules of water from interface respectively. Displacement of water molecules brought a great reorganization of double layer at the interface. These amines during corrosion form complexes with dissolved zinc and copper ions.(Author)

  1. Two-dimensional inorganic–organic hybrid semiconductors composed of double-layered ZnS and monoamines with aromatic and heterocyclic aliphatic rings: Syntheses, structures, and properties

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Sujing; Li, Jing, E-mail: jingli@rutgers.edu

    2015-04-15

    As an addition to the II–VI based inorganic–organic hybrid semiconductor family, five new two-dimensional (2D) double-layered structures have been synthesized employing monoamines with different aromatic or heterocyclic aliphatic rings. Zn{sub 2}S{sub 2}(bza) (1), Zn{sub 2}S{sub 2}(mbza) (2), Zn{sub 2}S{sub 2}(fbza) (3), Zn{sub 2}S{sub 2}(pca) (4), and Zn{sub 2}S{sub 2}(thfa) (5) (bza=benzylamine, mbza=4-methoxybenzylamine, fbza=4-flurobenzylamine, pca=3-picolylamine, and thfa=tetrahydrofurfurylamine) are prepared by solvothermal reactions and characterized by different analytical methods, including powder X-ray diffraction, optical diffuse reflection, thermogravimetric analysis and photoluminescence spectroscopy. The powder X-ray diffraction patterns show that all five compounds adopt 2D double-layered structures. Optical diffuse reflectance spectra of these compounds suggest that they have notably lower band gaps than those of the similar compounds composed of aliphatic alkyl amines. Their photoluminescence properties and thermal stability are also analyzed. - Graphical abstract: Five new members of two-dimensional double-layered 2D-Zn{sub 2}S{sub 2}(L) (L=Ligand) structures employing monoamines with different aromatic or heterocyclic aliphatic rings have been designed, synthesized, and characterized. - Highlights: • A new sub-family of II-VI based hybrid semiconductors are designed, synthesized, and structurally characterized using amines with aromatic or aliphatic cyclic rings. • These compounds have notably lower band gaps than those made of aliphatic alkyl amines, greatly broadening the range of band gaps of this material family. • They emit strongly with systematically tunable emission intensity and energy.

  2. Biodegradability of Plastics

    Directory of Open Access Journals (Sweden)

    Yutaka Tokiwa

    2009-08-01

    Full Text Available Plastic is a broad name given to different polymers with high molecular weight, which can be degraded by various processes. However, considering their abundance in the environment and their specificity in attacking plastics, biodegradation of plastics by microorganisms and enzymes seems to be the most effective process. When plastics are used as substrates for microorganisms, evaluation of their biodegradability should not only be based on their chemical structure, but also on their physical properties (melting point, glass transition temperature, crystallinity, storage modulus etc.. In this review, microbial and enzymatic biodegradation of plastics and some factors that affect their biodegradability are discussed.

  3. Thermal stability of aliphatic hyperbranched polyesters

    Directory of Open Access Journals (Sweden)

    Vuković Jasna

    2002-01-01

    Full Text Available The influence of the molar mass (generation, number and type of end groups on the thermal stability of aliphatic hyperbranched polyesters are presented in this study. Different end groups were obtained by modification of the samples with chlorides of propionic acid and stearic acid. The thermal stability of the hyperbranched polyesters was determined by thermogravimetry using a NET-ZSCH TG 209 instrument in nitrogen atmosphere at a heating rate of 10°C/min. A comparison of the temperatures obtained for mass losses of 5 20 and 40 wt% for unmodified samples showed that the thermal stability increased up to the fourth generation and then remained practically constant. An increase in the thermal stability of modified samples of the second, third and fourth generation was observed.

  4. PLA/PHA-Biodegradable Blends for Pneumothermic Fabrication of Nonwovens

    Directory of Open Access Journals (Sweden)

    Szuman Krzysztofa

    2016-09-01

    Full Text Available This study presents the results of research concerning fabrication of nonwovens from biodegradable polymer blends using the melt-blown method. The experiments performed within the framework of the research confirmed the possibility of obtaining polymer composites based on polylactide (PLA with poly(hydroxyalkanoates (PHA and another aliphatic-aromatic copolyester. The obtained products were subjected to the analyses of chemical structure using the Fourier Transform Infrared Spectroscopy(FTIR Attenuated Total Reflectance(ATR method. The physical and mechanical properties of the fabricated nonwoven layers were also tested, which confirmed a wide spectrum of their applicability, depending on the polymer composition used in production.

  5. Correlating biodegradation to magnetization in oil bearing sedimentary rocks

    Science.gov (United States)

    Emmerton, Stacey; Muxworthy, Adrian R.; Sephton, Mark A.; Aldana, Milagrosa; Costanzo-Alvarez, Vincenzo; Bayona, German; Williams, Wyn

    2013-07-01

    A relationship between hydrocarbons and their magnetic signatures has previously been alluded to but this is the first study to combine extensive geochemical and magnetic data of hydrocarbon-associated samples. We report a detailed study that identifies a connection between magnetic mineralogy and oil biodegradation within oil-bearing sedimentary units from Colombia, Canada Indonesia and the UK. Geochemical data reveal that all the oil samples are derived from mature type-II kerogens deposited in oxygen-poor environments. Biodegradation is evident to some extent in all samples and leads to a decrease in oil quality through the bacterially mediated conversion of aliphatic hydrocarbons to polar constituents. The percentage of oil components and the biodegradation state of the samples were compared to the magnetic susceptibility and magnetic mineralogy. A distinct decrease in magnetic susceptibility is correlated to decreasing oil quality and the amount of extractable organic matter present. Further magnetic characterization revealed that the high quality oils are dominated by pseudo-single domain grains of magnetite and the lower quality oils by larger pseudo-single domain to multidomain grains of magnetite and hematite. Hence, with decreasing oil quality there is a progressive dominance of multidomain magnetite as well as the appearance of hematite. It is concluded that biodegradation is a dual process, firstly, aliphatic hydrocarbons are removed thereby reducing oil quality and secondly, magnetic signatures are both created and destroyed. This complex relationship may explain why controversy has plagued previous attempts to resolve the connection between magnetics and hydrocarbon deposits. These findings reinforce the importance of bacteria within petroleum systems as well as providing a platform for the use of magnetization as a possible exploration tool to identify subsurface reservoirs and a novel proxy of hydrocarbon migration.

  6. Grey water biodegradability.

    Science.gov (United States)

    Ghunmi, Lina Abu; Zeeman, Grietje; Fayyad, Manar; van Lier, Jules B

    2011-02-01

    Knowing the biodegradability characteristics of grey water constituents is imperative for a proper design and operation of a biological treatment system of grey water. This study characterizes the different COD fractions of dormitory grey water and investigates the effect of applying different conditions in the biodegradation test. The maximum aerobic and anaerobic biodegradability and conversion rate for the different COD fractions is determined. The results show that, on average, dormitory grey water COD fractions are 28% suspended, 32% colloidal and 40% dissolved. The studied factors incubation time, inoculum addition and temperature are influencing the determined biodegradability. The maximum biodegradability and biodegradation rate differ between different COD fractions, viz. COD(ss), COD(col) and COD(diss). The dissolved COD fraction is characterised by the lowest degradation rate, both for anaerobic and aerobic conditions. The maximum biodegradability for aerobic and anaerobic conditions is 86 and 70% respectively, whereas the first order conversion rate constant, k₂₀, is 0.119 and 0.005 day⁻¹, respectively. The anaerobic and aerobic conversion rates in relation to temperature can be described by the Arrhenius relation, with temperature coefficients of 1.069 and 1.099, respectively. PMID:20658309

  7. Ecotoxicologically based environmental risk limits for several volatile aliphatic hydrocarbons

    NARCIS (Netherlands)

    Jong FMW de; Posthuma-Doodeman CJAM; Verbruggen EMJ; SEC

    2007-01-01

    This report describes ecotoxicological environmental risk limits derived for a number of volatile aliphatic hydrocarbons. On the basis of evaluated literature, the National Institute for Public Health and the Environment (RIVM) proposes ecotoxicological environmental risk limits for these compounds

  8. ANAEROBIC AND AEROBIC TREATMENT OF CHLORINATED ALIPHATIC COMPOUNDS

    Science.gov (United States)

    Biological degradation of 12 chlorinated aliphatic compounds (CACs) was assessed in bench-top reactors and in serum bottle tests. Three continuously mixed daily batch-fed reactor systems were evaluated: anaerobic, aerobic, and sequential-anaerobic-aerobic (sequential). Glucose,...

  9. Aliphatic nitro alcohols. Synthesis, chemical transformations and applications

    Energy Technology Data Exchange (ETDEWEB)

    Shvekhgeimer, Mai-Genrikh A [A.N. Kosygin Moscow State Textile Academy, Moscow (Russian Federation)

    1998-01-31

    The data on the synthesis, chemical transformations and practical use of aliphatic nitro alcohols published over the last 25 years are described systematically and analysed. The bibliography includes 316 references.

  10. Influence of biodegradation on benzocarbazole distri-butions in reservoired oils

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Partition coefficient difference of benzocarba-zole isomers between oil, water and mineral phase makes them auseful indicator to quantify petroleum migration distance. Because of their nitrogen-heteroatom andannelated aromatic cycles they are generally regarded asbeing more resistant and the effects of biodegradation ontheir concentrations and distributions have not previouslybeen investigated. Reservoir extracts from three wells lo-cated in the Leng43 block of the Liaohe Basin were analyzed to investigate their occurrence and the effect of biodegrada-tion. Both hydrocarbon biomarkers and benzocarbazole isomers show systematical changes with the increase extent of biodegradation in study columns. Carbazole compounds may be biodegraded in a similar way to that observed in aliphatic and aromatic hydrocarbons. The distance from oil water contact is a primary control factor for biodegradation. The concentrations of benzocarbazole isomers show a slight increase in the upper part of the columns then a sharp de-crease towards oil water contact (OWC). Among three iso-mers benzo[a]carbazole seems more susceptible to biode-gradation than other two isomers and benzo[b]carbazole has higher ability to res ist bacterial attack. Benzo[b]carba-zole/benzo- [a]carbazole ratios can sensitively indicate the degree of biodegradation and the benzocarbazole index (BCratio) cannot be directly used as a migration indicator inbiodegraded oils.

  11. BIODEGRADABLE MICROSPHERES: A REVIEW

    Directory of Open Access Journals (Sweden)

    Kaur Dupinder

    2012-12-01

    Full Text Available Microspheres are characteristically free flowing powders consisting of proteins or synthetic polymers having a particle size ranging from 1-1000 μm. The range of techniques for the preparation of microspheres offers a variety of opportunities to control aspects of drug administration and enhance the therapeutic efficacy of a given drug. Of the many polymeric drug delivery systems, biodegradable polymers have been used widely as drug delivery systems because of their biocompatibility and biodegradability. The majority of biodegradable polymers have been used in the form of microparticles, from which the incorporated drug is released to the environment in a controlled manner. They can be employed to deliver medication in a rate-controlled and sometimes targeted manner. Medication is released from a microsphere by drug leaching from the polymer or by degradation of the polymer matrix. This review discusses characteristics and degradation behaviors of biodegradable polymers which are currently used in drug delivery.

  12. Biodegradation of plastics.

    Science.gov (United States)

    Shimao, M

    2001-06-01

    Widespread studies on the biodegradation of plastics have been carried out in order to overcome the environmental problems associated with synthetic plastic waste. Recent work has included studies of the distribution of synthetic polymer-degrading microorganisms in the environment, the isolation of new microorganisms for biodegradation, the discovery of new degradation enzymes, and the cloning of genes for synthetic polymer-degrading enzymes. PMID:11404101

  13. Relationship between structure and the aerobic biodegradation of selected fuel hydrocarbons in soils

    International Nuclear Information System (INIS)

    The relationship between structure and aerobic soil biodegradation was examined for a series of aliphatic and aromatic fuel components. A simple microcosm approach, utilizing measurements of oxygen consumption, was used to generate biodegradation data for eleven C6 through C16 straight chain aliphatics and several aromatic compounds, including phenanthrene, naphthalene and 1 methylnaphthalene, in two silt loam soils. The microcosms consisted of 100 mL glass vials fitted with Mininerte reg-sign valves and typically contained about 40 g of soil. All compounds were added directly to the soil, without a carrier solvent, resulting in a soil concentration of approximately 200 ppm. Headspace concentrations of oxygen, converted to percent of theoretical oxygen demand (%ThOD) by subtracting appropriate controls at each sampling time, were analyzed over time using a gas chromatograph equipped with a thermal conductivity detector. All hydrocarbons displayed an acclimation period price to the onset of accelerated oxygen consumption resulting in a characteristic S-shaped biodegradation curve. An inverse relationship between acclimation period and hydrophobicity was observed for the n-alkanes in both soils. Interestingly, n-octanol, used to further investigate the degradation process, did not show a significant acclimation period. Additional ongoing research involves using a wider range of organic chemicals and a comparison of biodegradability obtained in unplanted soils with that in rhizosphere soil

  14. Differential effects of indole and aliphatic glucosinolates on lepidopteran herbivores.

    Science.gov (United States)

    Müller, René; de Vos, Martin; Sun, Joel Y; Sønderby, Ida E; Halkier, Barbara A; Wittstock, Ute; Jander, Georg

    2010-08-01

    Glucosinolates are a diverse group of defensive secondary metabolites that is characteristic of the Brassicales. Arabidopsis thaliana (L.) Heynh. (Brassicaceae) lines with mutations that greatly reduce abundance of indole glucosinolates (cyp79B2 cyp79B3), aliphatic glucosinolates (myb28 myb29), or both (cyp79B2 cyp79B3 myb28 myb29) make it possible to test the in vivo defensive function of these two major glucosinolate classes. In experiments with Lepidoptera that are not crucifer-feeding specialists, aliphatic and indole glucosinolates had an additive effect on Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae) larval growth, whereas Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae) and Manduca sexta (L.) (Lepidoptera: Sphingidae) were affected only by the absence of aliphatic glucosinolates. In the case of two crucifer-feeding specialists, Pieris rapae (L.) (Lepidoptera: Pieridae) and Plutella xylostella (L.) (Lepidoptera: Plutellidae), there were no major changes in larval performance due to decreased aliphatic and/or indole glucosinolate content. Nevertheless, choice tests show that aliphatic and indole glucosinolates act in an additive manner to promote larval feeding of both species and P. rapae oviposition. Together, these results support the hypothesis that a diversity of glucosinolates is required to limit the growth of multiple insect herbivores. PMID:20617455

  15. Photoluminescence Study of Carbon Nanotubes

    OpenAIRE

    Han, H. X.; Li, G. H.; Ge, W. K.; Wang, Z. P.; Xu, Z. Y.; Xie, S. S.; Chang, B H; Sun, L. F.; Wang, B S; G. Xu; Su, Z.B.

    2000-01-01

    ultiwalled carbon nanotubes, prepared by both electric arc discharge and chemical vapor deposition methods, show a strong visible light emission in photoluminescence experiments. All the samples employed in the experiments exhibit nearly same super-linear intensity dependence of the emission bands on the excitation intensity, and negligible temperature dependence of the central position and the line shapes of the emission bands. Based upon theoretical analysis of the electronic band structure...

  16. [Biodegradability of the components of natural hydrocarbon mixtures previously submitted to landfarming].

    Science.gov (United States)

    Pucci, G N; Pucci, O H

    2003-01-01

    The complex composition of the crude oil and the hydrocarbons that integrate the waste of the different stages of the oil industry turn this product a mixture that presents different difficulties for its elimination by biological methods. The objective of this paper was to study the biodegradation potential of autochthonous bacterial communities on hydrocarbons obtained from four polluted places and subjected to landfarming biorremediation system during a decade. The results showed a marked difference in biodegradability of the three main fractions of crude oil, aliphatic, aromatic, and polar fractions, obtained by column chromatography. All fractions were used as carbon source and energy. There were variations in the production of biomass among the different fractions as well as in the kinetics of biodegradation, according to the composition of each fraction.

  17. Colloidal Photoluminescent Amorphous Porous Silicon, Methods Of Making Colloidal Photoluminescent Amorphous Porous Silicon, And Methods Of Using Colloidal Photoluminescent Amorphous Porous Silicon

    KAUST Repository

    Chaieb, Sahraoui

    2015-04-09

    Embodiments of the present disclosure provide for a colloidal photoluminescent amorphous porous silicon particle suspension, methods of making a colloidal photoluminescent amorphous porous silicon particle suspension, methods of using a colloidal photoluminescent amorphous porous silicon particle suspension, and the like.

  18. Green and biodegradable electronics

    Directory of Open Access Journals (Sweden)

    Mihai Irimia-Vladu

    2012-07-01

    Full Text Available We live in a world where the lifetime of electronics is becoming shorter, now approaching an average of several months. This poses a growing ecological problem. This brief review will present some of the initial steps taken to address the issue of electronic waste with biodegradable organic electronic materials. Many organic materials have been shown to be biodegradable, safe, and nontoxic, including compounds of natural origin. Additionally, the unique features of such organic materials suggest they will be useful in biofunctional electronics; demonstrating functions that would be inaccessible for traditional inorganic compounds. Such materials may lead to fully biodegradable and even biocompatible/biometabolizable electronics for many low-cost applications. This review highlights recent progress in these classes of material, covering substrates and insulators, semiconductors, and finally conductors.

  19. Editorial: Biodegradable Materials

    Directory of Open Access Journals (Sweden)

    Carl Schaschke

    2014-11-01

    Full Text Available This Special Issue “Biodegradable Materials” features research and review papers concerning recent advances on the development, synthesis, testing and characterisation of biomaterials. These biomaterials, derived from natural and renewable sources, offer a potential alternative to existing non-biodegradable materials with application to the food and biomedical industries amongst many others. In this Special Issue, the work is expanded to include the combined use of fillers that can enhance the properties of biomaterials prepared as films. The future application of these biomaterials could have an impact not only at the economic level, but also for the improvement of the environment.

  20. Iodine - catalyzed prins cyclization of aliphatic and aromatic ketones

    Energy Technology Data Exchange (ETDEWEB)

    Kishore, K.R.; Reddy, K.; Silva Junior, Luiz F., E-mail: luizfsjr@iq.usp.br [Universidade de Sao Paulo (IQ/USP), SP (Brazil). Inst. de Quimica. Dept. de Quimica Fundamental

    2013-09-15

    Iodine-catalyzed Prins cyclization of homoallylic alcohols and ketones was investigated. Anhydrous conditions and inert atmosphere are not required in this metal-free protocol. The reaction of 2-(3,4-dihydronaphthalene-1-yl)propan-1-ol with six aliphatic symmetric ketones gave the desired products in 67-77% yield. Cyclization was performed with four aliphatic unsymmetric ketones, leading to corresponding pyrans in 66-76% yield. Prins cyclization was also accomplished with four aromatic ketones in 37-66% yield. Finally, Prins cyclization of the monoterpene isopulegol and acetone was successfully achieved. (author)

  1. In vitro and in vivo degradation profile of aliphatic polyesters subjected to electron beam sterilization.

    Science.gov (United States)

    Dånmark, S; Finne-Wistrand, A; Schander, K; Hakkarainen, M; Arvidson, K; Mustafa, K; Albertsson, A-C

    2011-05-01

    Degradation characteristics in response to electron beam sterilization of designed and biodegradable aliphatic polyester scaffolds are relevant for clinically successful synthetic graft tissue regeneration. Scaffold degradation in vitro and in vivo were documented and correlated to the macroscopic structure and chemical design of the original polymer. The materials tested were of inherently diverse hydrophobicity and crystallinity: poly(L-lactide) (poly(LLA)) and random copolymers from L-lactide and ε-caprolactone or 1,5-dioxepan-2-one, fabricated into porous and non-porous scaffolds. After sterilization, the samples underwent hydrolysis in vitro for up to a year. In vivo, scaffolds were surgically implanted into rat calvarial defects and retrieved for analysis after 28 and 91days. In vitro, poly(L-lactide-co-1,5-dioxepan-2-one) (poly(LLA-co-DXO)) samples degraded most rapidly during hydrolysis, due to the pronounced chain-shortening reaction caused by the sterilization. This was indicated by the rapid decrease in both mass and molecular weight of poly(LLA-co-DXO). Poly(L-lactide-co-ε-caprolactone) (poly(LLA-co-CL)) samples were also strongly affected by sterilization, but mass loss was more gradual; molecular weight decreased rapidly during hydrolysis. Least affected by sterilization were the poly(LLA) samples, which subsequently showed low mass loss rate and molecular weight decrease during hydrolysis. Mechanical stability varied greatly: poly(LLA-co-CL) withstood mechanical testing for up to 182 days, while poly(LLA) and poly(LLA-co-DXO) samples quickly became too brittle. Poly(LLA-co-DXO) samples unexpectedly degraded more rapidly in vitro than in vivo. After sterilization by electron beam irradiation, the three biodegradable polymers present widely diverse degradation profiles, both in vitro and in vivo. Each exhibits the potential to be tailored to meet diverse clinical tissue engineering requirements. PMID:21316490

  2. Photoluminescence of nanocrystals embedded in oxide matrices

    International Nuclear Information System (INIS)

    We used the theory of finite periodic systems to explain the photoluminescence spectra dependence on the average diameter of nanocrystals embedded in oxide matrices. Because of the broad matrix band gap, the photoluminescence response is basically determined by isolated nanocrystals and sequences of a few of them. With this model we were able to reproduce the shape and displacement of the experimentally observed photoluminescence spectra. (author)

  3. Photoinduced spectral changes of photoluminescent gold nanoclusters

    Science.gov (United States)

    Matulionytė, Marija; Marcinonytė, Raminta; Rotomskis, Ričardas

    2015-05-01

    Ultrasmall photoluminescent gold nanoclusters (Au NCs), composed of several atoms with sizes up to a few nanometers, have recently stimulated extensive interest. Unique molecule-like behaviors, low toxicity, and facile synthesis make photoluminescent Au NCs a very promising alternative to organic fluorophores and semiconductor quantum dots (QDs) in broad ranges of biomedical applications. However, using gold nanoparticles (Au NPs) for bioimaging might cause their degradation under continuous excitation with UV light, which might result in toxicity. We report spectral changes of photoluminescent 2-(N-morpholino) ethanesulfonic acid (MES)-coated (Au-MES) NCs under irradiation with UV/blue light. Photoluminescent water soluble Au-MES NCs with a photoluminescence (PL) band maximum at 476 nm (λex=420 nm) were synthesized. Under irradiation with 402 nm wavelength light the size of photoluminescent Au-MES NCs decreased (λem=430 nm). Irradiating the sample solution with 330 nm wavelength light, nonluminescent Au NPs were disrupted, and photoluminescent Au NCs (λem=476 nm) were formed. Irradiation with 330 nm wavelength light did not directly affect photoluminescent Au-MES NCs, however, increase in PL intensity indicated the formation of photoluminescent Au NCs from the disrupted nonluminescent Au NPs. This study gives a good insight into the photostability of MES-coated Au NPs under continuous excitation with UV/blue light.

  4. Grey water biodegradability

    NARCIS (Netherlands)

    Abu Ghunmi, L.; Zeeman, G.; Fayyad, M.; Van Lier, J.B.

    2010-01-01

    Knowing the biodegradability characteristics of grey water constituents is imperative for a proper design and operation of a biological treatment system of grey water. This study characterizes the different COD fractions of dormitory grey water and investigates the effect of applying different condi

  5. Introducing Aliphatic Substitution with a Discovery Experiment Using Competing Electrophiles

    Science.gov (United States)

    Curran, Timothy P.; Mostovoy, Amelia J.; Curran, Margaret E.; Berger, Clara

    2016-01-01

    A facile, discovery-based experiment is described that introduces aliphatic substitution in an introductory undergraduate organic chemistry curriculum. Unlike other discovery-based experiments that examine substitution using two competing nucleophiles with a single electrophile, this experiment compares two isomeric, competing electrophiles…

  6. Cloud condensation nuclei activity of aliphatic amine secondary aerosol

    Science.gov (United States)

    Aliphatic amines can form secondary aerosol via oxidation with atmospheric radicals (e.g. hydroxyl radical and nitrate radical). The resulting particle composition can contain both secondary organic aerosol (SOA) and inorganic salts. The fraction of organic to inorganic materials in the particulate ...

  7. Optimization of Biodegradability and Toxicity Testing of Degradation Product from Linear Alkyl BenzeneSulfonate (LAS Surfactant as Cleaning Detergent Agent

    Directory of Open Access Journals (Sweden)

    Neera Khairani

    2009-11-01

    Full Text Available Optimization of Biodegradability and Toxicity Testing of Degradation Product from Linear Alkyl BenzeneSulfonate (LAS Surfactant as Cleaning Detergent Agent. Linear Alkyl Benzene Sulfonate (LAS is a surfactantused in laundry detergent as cleaning agent and toxic to aquatic organisms. Results shows, with the LAS concentrationused (20 ppm in medium, adaptation time and Acinetobacter sp. growth has shown better biodegradation ability thanthree other bacteria used Pseudomonas putida, Pseudomonas fluorescence, Bacillaria spp. Thus, Acinetobacter sp isused further for biodegradation process of LAS. Based on its biodegradation half-life using Acinetobacter sp, and withmixed culture (± 52.32% and ± 46.82% respectively could be achieved in 4 (four days, LAS could be categorized as abiodegradable compound. The toxicity assay is based on tetrazolium dye reduction with Rhizobium meliloti as indicatororganism. LAS is more toxic than its intermediate product from biodegradation, with IC50 = 34.35 ppm, and theintermediate product, Ac and Cm, has IC50 = 446.19 ppm and 111.28 ppm respectively. Identification of intermediateproducts using IR and LC-MS analysis shows that the degradation product contains chemicals compounds withfunctional group as follows: benzene, benzoic acid, hydroxyl, and aliphatic carbons with large molecule weight. Untilits half-time degradation time, LAS biodegradation process only occurs at the aliphatic carbon chain, and have not yetreached the stage of aromatic ring opening.

  8. ODD-EVEN EFFECT OF LYOTROPIC LIQUID CRYSTALLINE PROPERTIES OF AROMATIC-ALIPHATIC COPOLYAMIDES

    Institute of Scientific and Technical Information of China (English)

    Xiao-zhong Lu; Yan-qing Lian; Xiao-gong Wang; Qi-xiang Zhou; Dc-shah Liu

    2001-01-01

    A series of aromatic-aliphatic copolyamides containing different aliphatic diamine units was synthesized by low temperature solution polycondensation. The liquid crystalline critical concentration (c*) and liquid crystalline critical temperature (7*) of these copolyamides exhibited an odd-even zigzag effect with the odd-even variation of carbon atom number in the aliphatic dimes used.

  9. Biodegradation of cyanuric acid.

    Science.gov (United States)

    Saldick, J

    1974-12-01

    Cyanuric acid biodegrades readily under a wide variety of natural conditions, and particularly well in systems of either low or zero dissolved-oxygen level, such as anaerobic activated sludge and sewage, soils, muds, and muddy streams and river waters, as well as ordinary aerated activated sludge systems with typically low (1 to 3 ppm) dissolved-oxygen levels. Degradation also proceeds in 3.5% sodium chloride solution. Consequently, there are degradation pathways widely available for breaking down cyanuric acid discharged in domestic effluents. The overall degradation reaction is merely a hydrolysis; CO(2) and ammonia are the initial hydrolytic breakdown products. Since no net oxidation occurs during this breakdown, biodegradation of cyanuric acid exerts no primary biological oxygen demand. However, eventual nitrification of the ammonia released will exert its usual biological oxygen demand.

  10. Aliphatics hydrocarbon content in surface sediment from Jakarta Bay, Indonesia

    Science.gov (United States)

    YAzis, M.; Asia, L.; Piram, A.; Doumenq, P.; Syakti, A. D.

    2016-02-01

    Sedimentary aliphatic hydrocarbons content have been studied quantitatively and qualitatively using GC/MS method in eight coastal stations located in the Jakarta Bay, North of Jakarta, Indonesia. The total concentrations n-alkanes have ranged from 480 μg.kg-1to 1,935 μg.kg-1sediment dry weight. Several ratios (e.g. CPI24-32, NAR, TAR, Pr/Phy, n-C17/Pr, n- C18/Phyt,n-C29/n-C17, Ʃn-alkanes/n-C16LMW/HMW, Paq and TMD) were used to evaluate the possible sources of terrestrial-marine inputs of these hydrocarbons in the sediments. The various origins of aliphatic hydrocarbons were generally biogenic, including both terrigenous and marine, with an anthropogenic pyrolytic contribution (petrogenic and biogenic combustion). Two stations (G,H) were thehighest concentration and had potential risk to environment

  11. Manganese-Mediated Coupling Reaction of Vinylarenes and Aliphatic Alcohols

    Science.gov (United States)

    Zhang, Wei; Wang, Nai-Xing; Bai, Cui-Bing; Wang, Yan-Jing; Lan, Xing-Wang; Xing, Yalan; Li, Yi-He; Wen, Jia-Long

    2015-10-01

    Alcohols and alkenes are the most abundant and commonly used organic building blocks in the large-scale chemical synthesis. Herein, this is the first time to report a novel and operationally simple coupling reaction of vinylarenes and aliphatic alcohols catalyzed by manganese in the presence of TBHP (tert-butyl hydroperoxide). This coupling reaction provides the oxyalkylated products of vinylarenes with good regioselectivity and accomplishes with the principles of step-economies. A possible reaction mechanism has also been proposed.

  12. Swift Heavy Ion Induced Modification of Aliphatic Polymers

    OpenAIRE

    Hossain, Umme Habiba

    2015-01-01

    In this thesis, the high energy heavy ion induced modification of aliphatic polymers is studied. Two polymer groups, namely polyvinyl polymers (PVF, PVAc, PVA and PMMA) and fluoropolymers (PVDF, ETFE, PFA and FEP) were used in this work. Polyvinyl polymers were investigated since they will be used as insulating materials in the superconducting magnets of the new ion accelerators of the planned International Facility for Antiproton and Ion Research (FAIR) at the GSI Helmholtz-Centre of Heavy I...

  13. Reactions of aliphatic free radicals with transition metal complexes

    International Nuclear Information System (INIS)

    A pulse radiolytic study of the reactions of copper ions with free aliphatic radicals was carried out. It was found that all the aliphatic radicals studied react with Cusub(aq)sup(+) and Cusub(aq)sup(2+), forming an unstable compound, with a carbon-copper σ bond, according to the reaction Mnsub(aq)sup(n+)+ . CR1R2R3 → M-CR1R2Rsub(3)sup(n+). It was also found that the rates of formation of the intermediate compounds, their half-lives and their decomposition mechanism depend on the properties of the radical and the cation. Experiments for the determination of the influence of macrocyclic ligands of the Curtis type on the stability of intermediate compounds failed because of insufficient concentrations of these ligands. The processes of ligand hydridization, isomerization and decomposition for the macrocylic complexes Cusup(I)L were also studied. These complexes, which are unstable, are formed as a result of the reaction of the stable Cusup(II)L complexes with certain free aliphatic radicals

  14. Cost-Benefit Analysis for Alternatives to Aliphatic Isocyanate Polyurethanes

    Science.gov (United States)

    Lewis, Pattie

    2007-01-01

    NASA and Air Force Space Command (AFSPC) have similar missions and therefore similar facilities and structures in similar environments. The standard practice for protecting metallic substrates in atmospheric environments is the application of an applied coating system. The most common topcoats used in coating systems are polyurethanes that contain isocyanates. Isocyanates are classified as potential human carcinogens and are known to cause cancer in animals. The primary objective of this effort was to demonstrate and validate alternatives to aliphatic isocyanate polyurethanes resulting in one or more isocyanate-free coatings qualified for use at AFSPC and NASA installations participating in this project. This Cost-Benefit Analysis (CBA) quantifies the estimated capital and process costs of coating alternatives and cost savings relative to the current coatings. The estimates in this CBA are to be used for assessing the relative merits of the selected alternatives. The actual economic effects at any specific facility will depend on the alternative material or technology implemented, the number of actual applications converted, future workloads, and other factors . The participants initially considered eighteen (18) alternative coatings as described in the Potential Alternatives Report entitled Potential Alternatives Report for Validation of Alternatives to Aliphatic Isocyanate Polyurethanes, prepared by ITB. Of those, 8 alternatives were selected for testing in accordance with the Joint Test Protocol entitled Joint Test Protocol for Validation of Alternatives to Aliphatic Isocyanate Polyurethanes, and the Field Test Plan entitled Field Evaluations Test Plan for Validation of Alternatives 10 Aliphatic Isocyanate Polyurethanes, both of which were prepared by ITB. A joint Test Report entitled Joint Test Report for Validation of Alternatives to Aliphatic Isocyanate Polyurethanes, prepared by ITB, documents the results of the laboratory and field testing, as well as any

  15. Synthesis of photoluminescent carbon nanoparticles from graphite

    Energy Technology Data Exchange (ETDEWEB)

    Fu Xiaobo; Li Dianhong; Zhang Yuanming, E-mail: tzhangymjnu@163.com [School of Life Science and Technology, Jinan University, Department of Chemistry (China)

    2013-04-15

    Photoluminescent carbon nanoparticles (CNPs) with diameters ranging from 1.5 to 6.5 nm were synthesized from raw graphite without surface passivation. The photoluminescent (PL) emission spectra illustrate that both excitation wavelength and solution pH can significantly influence the maximum emission wavelength and PL intensity of the CNP solution. As the excitation wavelength decreases and solution pH increases, a blue shift in the maximum PL emission wavelength occurs.

  16. Synthesis of photoluminescent carbon nanoparticles from graphite

    International Nuclear Information System (INIS)

    Photoluminescent carbon nanoparticles (CNPs) with diameters ranging from 1.5 to 6.5 nm were synthesized from raw graphite without surface passivation. The photoluminescent (PL) emission spectra illustrate that both excitation wavelength and solution pH can significantly influence the maximum emission wavelength and PL intensity of the CNP solution. As the excitation wavelength decreases and solution pH increases, a blue shift in the maximum PL emission wavelength occurs.

  17. Biodegradation and corrosion behavior of manganese oxidizer Bacillus cereus ACE4 in diesel transporting pipeline

    International Nuclear Information System (INIS)

    The degradation problem of petroleum products arises since hydrocarbon acts as an excellent food source for a wide variety of microorganisms. Microbial activity leads to unacceptable level of turbidity, corrosion of pipeline and souring of stored product. The present study emphasizes the role of Bacillus cereus ACE4 on degradation of diesel and its influence on corrosion of API 5LX steel. A demonstrating bacterial strain ACE4 was isolated from corrosion products and 16S rRNA gene sequence analysis showed that it has more than 99% similarity with B. cereus. The biodegradation and corrosion studies revealed that B. cereus degraded the aliphatic protons and aromatic protons in diesel and is capable of oxidizing ferrous/manganese into oxides. This is the first report that discloses the involvement of manganese oxidizer B. cereus ACE4 on biodegradation of diesel and its influence on corrosion in a tropical country pipeline

  18. Degradation kinetics of chlorinated aliphatic hydrocarbons by methane oxidizers naturally-associated with wetland plant roots.

    Science.gov (United States)

    Powell, C L; Goltz, M N; Agrawal, A

    2014-12-01

    Chlorinated aliphatic hydrocarbons (CAHs) are common groundwater contaminants that can be removed from the environment by natural attenuation processes. CAH biodegradation can occur in wetland environments by reductive dechlorination as well as oxidation pathways. In particular, CAH oxidation may occur in vegetated wetlands, by microorganisms that are naturally associated with the roots of wetland plants. The main objective of this study was to evaluate the cometabolic degradation kinetics of the CAHs, cis-1,2-dichloroethene (cisDCE), trichloroethene (TCE), and 1,1,1-trichloroethane (1,1,1TCA), by methane-oxidizing bacteria associated with the roots of a typical wetland plant in soil-free system. Laboratory microcosms with washed live roots investigated aerobic, cometabolic degradation of CAHs by the root-associated methane-oxidizing bacteria at initial aqueous [CH4] ~1.9mgL(-1), and initial aqueous [CAH] ~150μgL(-1); cisDCE and TCE (in the presence of 1,1,1TCA) degraded significantly, with a removal efficiency of approximately 90% and 46%, respectively. 1,1,1TCA degradation was not observed in the presence of active methane oxidizers. The pseudo first-order degradation rate-constants of TCE and cisDCE were 0.12±0.01 and 0.59±0.07d(-1), respectively, which are comparable to published values. However, their biomass-normalized degradation rate constants obtained in this study were significantly smaller than pure-culture studies, yet they were comparable to values reported for biofilm systems. The study suggests that CAH removal in wetland plant roots may be comparable to processes within biofilms. This has led us to speculate that the active biomass may be on the root surface as a biofilm. The cisDCE and TCE mass losses due to methane oxidizers in this study offer insight into the role of shallow, vegetated wetlands as an environmental sink for such xenobiotic compounds.

  19. Biodegradation of Polypropylene Nonwovens

    Science.gov (United States)

    Keene, Brandi Nechelle

    The primary aim of the current research is to document the biodegradation of polypropylene nonwovens and filament under composting environments. To accelerate the biodegradat ion, pre-treatments and additives were incorporated into polypropylene filaments and nonwovens. The initial phase (Chapter 2) of the project studied the biodegradation of untreated polypropylene with/without pro-oxidants in two types of composting systems. Normal composting, which involved incubation of samples in food waste, had little effect on the mechanical properties of additive-free spunbond nonwovens in to comparison prooxidant containing spunbond nonwovens which were affected significantly. Modified composting which includes the burial of samples with food and compressed air, the polypropylene spunbond nonwovens with/without pro-oxidants displayed an extreme loss in mechanical properties and cracking on the surface cracking. Because the untreated spunbond nonwovens did not completely decompose, the next phase of the project examined the pre-treatment of gamma-irradiation or thermal aging prior to composting. After exposure to gamma-irradiation and thermal aging, polypropylene is subjected to oxidative degradation in the presence of air and during storage after irradiat ion. Similar to photo-oxidation, the mechanism of gamma radiation and thermal oxidative degradation is fundamentally free radical in nature. In Chapter 3, the compostability of thermal aged spunbond polypropylene nonwovens with/without pro-oxidant additives. The FTIR spectrum confirmed oxidat ion of the polypropylene nonwovens with/without additives. Cracking on both the pro-oxidant and control spunbond nonwovens was showed by SEM imaging. Spunbond polypropylene nonwovens with/without pro-oxidants were also preirradiated by gamma rays followed by composting. Nonwovens with/without pro-oxidants were severely degraded by gamma-irradiation after up to 20 kGy exposure as explained in Chapter 4. Furthermore (Chapter 5), gamma

  20. Progresses in Research of Aliphatic Polycarbonates%脂肪族聚碳酸酯的研究进展

    Institute of Scientific and Technical Information of China (English)

    刘峰; 翟刚; 李建国; 刘绍英; 杨先贵; 王公应

    2013-01-01

    综述了通过环氧化物与CO2共聚法、脂肪族环状碳酸酯开环聚合法及脂肪族二元醇与碳酸二烃基酯聚合法合成脂肪族聚碳酸酯(APCs)的研究进展,特别是对各种反应体系所采用催化剂的突破性研究成果进行了介绍,并对反应机理进行了分析.讨论了APCs的结构与其生物降解性及热分解性等性能的关系;结合APCs的性质介绍了它在医用材料、陶瓷及橡胶工业等领域的应用.比较了合成APCs的不同途径的特点,并对APCs材料的合成方法及其应用的发展趋势进行了展望.%The catalysts for the synthesis of aliphatic polycarbonates(APCs) were summarized according to three reaction systems,namely the copolymerization of carbon dioxide with epoxides,the ring-opening polymerization of cyclic carbonates and the two-step polycondensation of dialkyl carbonates and aliphatic diols.Particularly,the new research achievements for the catalysts and the mechanism of the reactions were introduced.The relationship between the structures and the performances of APCs,such as biodegradability and thermal decomposition,were discussed.The applications of APCs in medical materials,ceramics,rubber industry and so on were introduced.The synthesis of APCs by different methods were analyzed briefly.The development trend of APCs in future was forecasted.

  1. Comparison of finishing application for aliphatic polyurethane dispersions and polyurethane/polyacrylate composite emulsions

    OpenAIRE

    Chai, S; Zhang, Zhongyi

    2010-01-01

    Aliphatic and aromatic cationic aqueous polyurethane (PU-1, PU-2), aliphatic anionic aqueous polyurethanes (PU-3, PU-4) were prepared with polyether glycol, polyether polyol, toluene diisocyanate and isophorone diisocyanate as raw materials. The core-shell polyurethane/polyacrylate composite emulsions (PUA-5, PUA-6) as well as interpenetrating PUA composite emulsions (PUA-7,PUA-8) were prepared by seeded emulsion polymerization, the aliphatic anionic aqueous PU dispersions were used as seed p...

  2. Synthesis and Characterization of Aliphatic-Aromatic Hyperbranched Polyesters

    Institute of Scientific and Technical Information of China (English)

    唐黎明; 张晓龙; 邱藤; 刘德山

    2002-01-01

    Hyperbranched polymers possess special architectures and have potential applications in various areas. In this study, two AB2 monomers, dipropyl 5-(hydroxyethoxy) isophthalate (I) and 5-hydroxyethoxyisophthaic acid (II), were prepared. By bulk polycondensation of each monomer, two aliphatic-aromatic hyperbranched polyesters were prepared and characterized by 1H-nuclear magnetic resonance (1H-NMR), differential scanning calorimetry (DSC), thermogravimetry analysis (TGA), and scanning electron microscopy (SEM). Compared with all-aromatic hyperbranched polyesters, the prepared polymers showed lower glass transition temperatures in connection with the moderate decrease in their decomposition temperatures.

  3. Synthesis of aliphatic amidediol and used as a novel mixed plasticizer for thermoplastic starch

    Institute of Scientific and Technical Information of China (English)

    Jian She Zhang; Jiu Gao Yu; Ying Wu; Xiao Fei Ma

    2008-01-01

    In this paper,aliphatic amidediol was synthesized and mixed with glycerol used as a plasticizer for preparing thermoplastic starch (AGPTPS).The yield of aliphatic amidediol was 91%.FT-IR expressed that the mixture of aliphatic amidediol and glycerol formed stronger and stable hydrogen bond with starch molecules compared to the native cornstarch.By scanning electron microscope (SEM) native cornstarch granules were proved to transfer to a homogeneous continuous system.After being stored for a period time at room temperature,the mechanical properties of AGPTPS were also studied.As a mixed plasticizer,aliphatic amidediol and glycerol would be practical to extend TPS application scopes.

  4. Biodegradable micromechanical sensors

    DEFF Research Database (Denmark)

    Keller, Stephan Sylvest; Greve, Anders; Schmid, Silvan;

    The development of biopolymers for food packaging, medical engineering or drug delivery is a growing field of research [1]. At the same time, the interest in methods for detailed analysis of biopolymers is increasing. Micromechanical sensors are versatile tools for the characterization of mechani......The development of biopolymers for food packaging, medical engineering or drug delivery is a growing field of research [1]. At the same time, the interest in methods for detailed analysis of biopolymers is increasing. Micromechanical sensors are versatile tools for the characterization...... of biopolymers to microfabrication is challenging, as these polymers are affected by common processes such as photolithography or wet etching. Here, we present two methods for fabrication of biodegradable micromechanical sensors. First, we fabricated bulk biopolymer microcantilevers using nanoimprint lithography...

  5. Lung toxicity of biodegradable nanoparticles.

    Science.gov (United States)

    Fattal, Elias; Grabowski, Nadége; Mura, Simona; Vergnaud, Juliette; Tsapis, Nicolas; Hillaireau, Hervé

    2014-10-01

    Biodegradable nanoparticles exhibit high potentialities for local or systemic drug delivery through lung administration making them attractive as nanomedicine carriers. However, since particulate matter or some inorganic manufactured nanoparticles exposed to lung cells have provoked cytotoxic effects, inflammatory and oxidative stress responses, it becomes important to investigate nanomedicine toxicity towards the lungs. This is the reason why, in the present review, the behavior of biodegradable nanoparticles towards the different parts of the respiratory tract as well as the toxicological consequences, measured on several models in vitro, ex vivo or in vivo, are described. Taken all together, the different studies carried out so far conclude on no or slight toxicity of biodegradable nanoparticles.

  6. Polarized Raman spectra and intensities of aliphatic amino acids

    Science.gov (United States)

    Himmler, Hans J.; Eysel, Hans H.

    1989-01-01

    Raman spectra of aliphatic α- L-amino acids, glycine, alanine, and valine were re-investigated both in aqueous solution and deuterium oxide solution. The spectra were taken of the zwitterionic and of the completely deprotonated form of the amino acids. Spectra of leucine and isoleucine were studied in water at the isoelectric point. Spectra were recorded both with parallel and perpendicular polarization and the isotropic and anisotropic scattering components were isolated. The integrated intensities of CH stretch, CC stretch and carboxylate bend vibrations are discussed. Linear relations between the number of CC and CH bonds and the total scattered intensity in the appropriate spectral regions are observed. The sum over the carboxylate modes shows characteristic intensities for the first three members of the aliphatic amino acids. An increase of isotropic scattering of ϱ co 2 near 510 cm -1 with increasing chain length of the amino acid (or with increasing concentration) is interpreted as the result of micelle formation.

  7. Resonance enhancement of photoluminescence from silicon nanocrystallites

    Energy Technology Data Exchange (ETDEWEB)

    Belyakov, L.V.; Goryachev, D.N.; Sreseli, O.M. [Ioffe Physicotechnical Institute, Russian Academy of Sciences, St. Petersburg (Russian Federation)

    2009-02-15

    An interaction of molecular oxygen and p-Si nanocrystallites in HF-ethanolic solution with simultaneous illumination has been investigated. It is shown that after such treatment with white-light exposure the photoluminescence from nanocrystallites enhances substantially caused by photogenerated singlet forms of molecular oxygen. In the case of monochromatic illumination with photon energy in the range 2.5-0.95 eV dependence of photoluminescence intensity after the treatment on photon energy used shows resonant peaks corresponding to the absorbance peaks of excited molecular oxygen. To our knowledge such photoluminescence peaks in porous silicon spectroscopy have been observed for the first time. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  8. Study of the electron beam irradiation effect on some properties of aromatic aliphatic copolyester films; Estudo do efeito da radiacao por feixe de eletrons nas propriedades de filmes de copoliester alifatico aromatico

    Energy Technology Data Exchange (ETDEWEB)

    Poveda, Patricia Negrini Siqueira

    2008-07-01

    Biodegradable and green plastics are the new tendency in the world. The effect of the electron beam irradiation in aromatic aliphatic copolyester and the blend with corn starch films (Ecoflex{sup R} and Ecobras{sup R}) were studied by tensile strength at break, elongation at break, Scanning Electronic Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FT-IR), Differential Scanning Calorimetry (DSC), crosslinking degree and biodegradability. The measurements in both, the machine direction and the transverse direction were made for mechanical tests. It was found that, the electron irradiation caused an increase in the strength at break of the blend with corn starch film, when doses of up to 10 kGy were applied. A significant decrease of the elongation at break of the blend with corn starch was observed at doses of 10 kGy and 40 kGy. It was not found important change in tensile properties for aromatic aliphatic copolyester. Structural changes of the samples (crosslinking or degradation) by SEM were not observed. The FT-IR identified the characteristic peaks of each involved functional group (copolyester and corn starch). However, it was not found bands of oxidation of the samples. In the DSC, changes in the melting temperature of the irradiated Ecoflex{sup R} and Ecobras{sup R} samples, was not identified when compared with the samples of reference. However, it was verified a reduction in the melting enthalpy of the Ecobras{sup R} samples after irradiation. The Ecobras{sup R} material presented crosslinking, when submitted to doses of 10 kGy and 40 kGy. The Ecoflex{sup R} material did not present crosslinking when submitted to these doses. The biodegradability of the materials was evaluated by two methods of test: soil simulated and enzymatic. In both methods, the irradiated samples presented faster biodegradation than the references not irradiated. (author)

  9. Progress of Aliphatic Polyester Grafted Polysaccharides in Biomimetic Materials%脂肪族聚酯接枝聚多糖仿生材料研究进展!

    Institute of Scientific and Technical Information of China (English)

    周开文; 宋继胜

    2012-01-01

    The tendency of biomedical materials is to design the novel biomaterials by biomimetic or bioinspired methods.Both aliphatic polyester and polysaccharides are biodegradable and biocompatible,and they extensively applied in engineering,gene delivery and drug delivery system.The paper reviewed the new research in aliphatic grafted polysaccharides and commented on the questions and the prospect of the biomimetic materials.%该文针对脂肪族聚酯与多糖都具有可生物降解、生物相容性等优点,以脂肪族聚酯接枝改性聚多糖并成为材料研究的热点,制备完全可生物降解的生物仿生材料,在药物控制释放、组织工程支架材料、基因转染载体材料等方面具有广泛应用。该文综述了脂肪族聚酯与多糖接枝改性的研究进展,同时讨论了各种接枝改性方法的特点并对于这类生物仿生材料目前存在的问题以及前景进行了展望。

  10. Progress of biodegradable metals

    Institute of Scientific and Technical Information of China (English)

    Huafang Li; Yufeng Zheng; Ling Qin

    2014-01-01

    Biodegradable metals (BMs) are metals and alloys expected to corrode gradually in vivo, with an appropriate host response elicited by released corrosion products, then dissolve completely upon fulfilling the mission to assist with tissue healing with no implant residues. In the present review article, three classes of BMs have been systematically reviewed, including Mg-based, Fe-based and Zn-based BMs. Among the three BM systems, Mg-based BMs, which now have several systems reported the successful of clinical trial results, are considered the vanguards and main force. Fe-based BMs, with pure iron and Fe–Mn based alloys as the most promising, are still on the animal test stage. Zn-based BMs, supposed to have the degradation rate between the fast Mg-based BMs and the slow Fe-based BMs, are a rising star with only several reports and need much further research. The future research and development direction for the BMs are proposed, based on the clinical requirements on controllable degradation rate, prolonged mechanical stability and excellent biocompat-ibility, by optimization of alloy composition design, regulation on microstructure and mechanical properties, and following surface modification.

  11. Progress of biodegradable metals

    Directory of Open Access Journals (Sweden)

    Huafang Li

    2014-10-01

    Full Text Available Biodegradable metals (BMs are metals and alloys expected to corrode gradually in vivo, with an appropriate host response elicited by released corrosion products, then dissolve completely upon fulfilling the mission to assist with tissue healing with no implant residues. In the present review article, three classes of BMs have been systematically reviewed, including Mg-based, Fe-based and Zn-based BMs. Among the three BM systems, Mg-based BMs, which now have several systems reported the successful of clinical trial results, are considered the vanguards and main force. Fe-based BMs, with pure iron and Fe–Mn based alloys as the most promising, are still on the animal test stage. Zn-based BMs, supposed to have the degradation rate between the fast Mg-based BMs and the slow Fe-based BMs, are a rising star with only several reports and need much further research. The future research and development direction for the BMs are proposed, based on the clinical requirements on controllable degradation rate, prolonged mechanical stability and excellent biocompatibility, by optimization of alloy composition design, regulation on microstructure and mechanical properties, and following surface modification.

  12. Mass spectrometry study of the sublimation of aliphatic dipeptides

    Science.gov (United States)

    Badelin, V. G.; Tyunina, E. Yu.; Krasnov, A. V.; Tyunina, V. V.; Giricheva, N. I.; Girichev, A. V.

    2012-03-01

    The sublimation of glycyl-L-α-alanine (Gly-Ala), L-α-alanyl-L-α-alanine (Ala-Ala), and DL-α-alanyl-DL-α-valine (Ala-Val) aliphatic dipeptides is studied by electron ionization mass spectrometry in combination with Knudsen effusion. The temperature range in which substances sublime as monomer molecular forms is determined. Enthalpies of sublimation Δs H°( T) are determined for Gly-Ala, Ala-Ala, and Ala-Val. It is shown that the enthalpy of sublimation of dipeptides increases with an increase in the side hydrocarbon radical. The unknown Δs H°(298) values for 17 amino acids and nine dipeptides are estimated using the proposed "structure-property" correlation model, in which the geometry and electron characteristics of molecules are used as structural descriptors.

  13. Diagnostic meaning of intestinal wall photoluminescence changes

    Science.gov (United States)

    Besaha, R. M.; Hrynchuk, F. V.; Polyansky, I. Y.

    2006-05-01

    Diagnostics of inflammatory-destructive diseases of the abdominal cavity organs is performed by the determined spectra of luminescence of venous blood plasma. The shift of the photoluminescence maximum beginning with the wave-length 469 nm into short-wave zone proves the presence of the acute inflammatory-destructive diseases and exacerbation of the pathological process.

  14. Blue photoluminescent carbon nanodots from limeade.

    Science.gov (United States)

    Suvarnaphaet, Phitsini; Tiwary, Chandra Sekhar; Wetcharungsri, Jutaphet; Porntheeraphat, Supanit; Hoonsawat, Rassmidara; Ajayan, Pulickel Madhavapanicker; Tang, I-Ming; Asanithi, Piyapong

    2016-12-01

    Carbon-based photoluminescent nanodot has currently been one of the promising materials for various applications. The remaining challenges are the carbon sources and the simple synthetic processes that enhance the quantum yield, photostability and biocompatibility of the nanodots. In this work, the synthesis of blue photoluminescent carbon nanodots from limeade via a single-step hydrothermal carbonization process is presented. Lime carbon nanodot (L-CnD), whose the quantum yield exceeding 50% for the 490nm emission in gram-scale amounts, has the structure of graphene core functionalized with the oxygen functional groups. The micron-sized flake of the as-prepared L-CnD powder exhibits multicolor emission depending on an excitation wavelength. The L-CnDs are demonstrated for rapidly ferric-ion (Fe(3+)) detection in water compared to Fe(2+), Cu(2+), Co(2+), Zn(2+), Mn(2+) and Ni(2+) ions. The photoluminescence quenching of L-CnD solution under UV light is used to distinguish the Fe(3+) ions from others by naked eyes as low concentration as 100μM. Additionally, L-CnDs provide exceptional photostability and biocompatibility for imaging yeast cell morphology. Changes in morphology of living yeast cells, i.e. cell shape variation, and budding, can be observed in a minute-period until more than an hour without the photoluminescent intensity loss. PMID:27612786

  15. Surface States and Photoluminescence From Porous Silicon

    OpenAIRE

    Md. Nazrul Islam; Satyendra Kumar

    2011-01-01

    Photoluminescence (PL) spectra of freshly electrochemically etched porous silicon layers anodized under various condition have been measured and analyzed according to quantum confinement (QC) model and surface state models. The results support the combination of QC and surface state models for visible PL from fresh PS layers.

  16. Sodium hypochlorite oxidation of petroleum aliphatic contaminants in calcareous soils.

    Science.gov (United States)

    Picard, François; Chaouki, Jamal

    2016-02-01

    This research project investigated the sodium hypochlorite (NaClO) oxidation of aliphatic petroleum contaminants (C10-C50) in a calcareous soil (average 5473 ppm C10-C50, 15 wt% Ca), which had been excavated from a contaminated industrial site. The decontamination objective was to lower the C10-C50 concentration to 700 ppm. CO2 acidity was used in the project to boost the NaClO oxidation yield and seems to have played a role in desorbing the natural organic matter. The experimental conditions were a 2- to 16-h reaction time, at room temperature, with a 1 to 12.5 wt% NaClO oxidative solution and a fixed 2:1 solution-to-soil ratio. With a 3 wt% NaClO solution and with a CO2 overhead, the NaClO dosage requirement was maintained below 60 g NaClO/g of oxidized C10-C50 over the entire decontamination range. The strong chlorine smell remaining after the reaction was completed suggests that part of the NaClO requirement can be recycled. Except traces of chloroform, there were no regulation-listed organochloride contaminants detected on either the treated soil samples or leachates and the total count of chlorinated compounds in treated soil samples was below the detection limit of 250 mg/kg. The NaClO oxidation mechanism on aliphatic substrates might be triggered by transition metals, such as manganese, but no attempt has been made to investigate the oxidation mechanism. Further investigations would include a constant-fed NaClO system and other techniques to lower the required NaClO dosage. PMID:26702553

  17. 40 CFR 721.3830 - Formaldehyde, reaction products with an alkylated phenol and an aliphatic amine (generic).

    Science.gov (United States)

    2010-07-01

    ... an alkylated phenol and an aliphatic amine (generic). 721.3830 Section 721.3830 Protection of... products with an alkylated phenol and an aliphatic amine (generic). (a) Chemical substance and significant..., reaction products with an alkylated phenol and an aliphatic amine (PMN P-99-0531) is subject to...

  18. Adhesion of biocompatible and biodegradable micropatterned surfaces

    NARCIS (Netherlands)

    Kaiser, J.S.; Kamperman, M.M.G.; Souza, E.J.; Schick, B.; Arzt, E.

    2011-01-01

    We studied the effects of pillar dimensions and stiffness of biocompatible and biodegradable micropatterned surfaces on adhesion on different compliant substrates. The micropatterned adhesives were based on biocompatible polydimethylsiloxane (PDMS) and biodegradable poly(lactic-co-glycolic) acid (PL

  19. Poly (3-Hydroxyalkanoates: Biodegradable Plastics

    Directory of Open Access Journals (Sweden)

    Surbhi Jain

    2013-03-01

    Full Text Available During the 1920’s, a polyester called poly (3-hydroxybutyrate was discovered in bacterial cells. This compound, otherwise known as PHB, is part of a polyester family called polyhydroxyalkanoates (PHAs. Polyhydroxyalkanoates are used as an energy and carbon sto rage compound within certain bacterial cells. Polyhydroxyalkanoates (PHAs are thermoplastic, biodegradable polyesters synthesized by some bacteria from renewable carbon sources. However, their application is limited by high production cost. Polyhydroxyalkanoates (PHAs have attracted research and commercial interests worldwide because they can be used as biodegradable thermoplastics and also because they can be produced from renewable resources. This review will present an overview on synthesis and degradation of polyhydroxyalkanoates (PHAs, development as biodegradable plastics and its potential production from renewable resources such as palm oil products.

  20. Testing biodegradability with standardized methods.

    Science.gov (United States)

    Pagga, U

    1997-12-01

    Laboratory test methods are used by industry laboratories to determine biodegradability, an important parameter for the evaluation of the ecological behaviour of substances. Biodegradability has a key role due to the simple fact that a degradable substance will cause no long term risk in the environment. The great variety of biodegradation processes in the natural environment and in technical plants for treating waste water and solid wastes gave rise to a rather large number of test methods based on different test principles. To guarantee the acceptance of the test results by authorities and customers internationally standardized methods (ISO, OECD) and established quality criteria (GLP, EN 45,000, ISO 9000) are used. PMID:9415981

  1. Petroleum biodegradation in marine environments.

    Science.gov (United States)

    Harayama, S; Kishira, H; Kasai, Y; Shutsubo, K

    1999-08-01

    Petroleum-based products are the major source of energy for industry and daily life. Petroleum is also the raw material for many chemical products such as plastics, paints, and cosmetics. The transport of petroleum across the world is frequent, and the amounts of petroleum stocks in developed countries are enormous. Consequently, the potential for oil spills is significant, and research on the fate of petroleum in a marine environment is important to evaluate the environmental threat of oil spills, and to develop biotechnology to cope with them. Crude oil is constituted from thousands of components which are separated into saturates, aromatics, resins and asphaltenes. Upon discharge into the sea, crude oil is subjected to weathering, the process caused by the combined effects of physical, chemical and biological modification. Saturates, especially those of smaller molecular weight, are readily biodegraded in marine environments. Aromatics with one, two or three aromatic rings are also efficiently biodegraded; however, those with four or more aromatic ring are quite resistant to biodegradation. The asphaltene and resin fractions contain higher molecular weight compounds whose chemical structures have not yet been resolved. The biodegradability of these compounds is not yet known. It is known that the concentrations of available nitrogen and phosphorus in seawater limit the growth and activities of hydrocarbon-degrading microorganisms in a marine environment. In other words, the addition of nitrogen and phosphorus fertilizers to an oil-contaminated marine environment can stimulate the biodegradation of spilled oil. This notion was confirmed in the large-scale operation for bioremediation after the oil spill from the Exxon Valdez in Alaska. Many microorganisms capable of degrading petroleum components have been isolated. However, few of them seem to be important for petroleum biodegradation in natural environments. One group of bacteria belonging to the genus

  2. Reconstructive Phase Transition in Ultrashort Peptide Nanostructures and Induced Visible Photoluminescence.

    Science.gov (United States)

    Handelman, Amir; Kuritz, Natalia; Natan, Amir; Rosenman, Gil

    2016-03-29

    A reconstructive phase transition has been found and studied in ultrashort di- and tripeptide nanostructures, self-assembled from biomolecules of different compositions and origin such as aromatic, aliphatic, linear, and cyclic (linear FF-diphenylalanine, linear LL-dileucine, FFF-triphenylalanine, and cyclic FF-diphenylalanine). The native linear aromatic FF, FFF and aliphatic LL peptide nanoensembles of various shapes (nanotubes and nanospheres) have asymmetric elementary structure and demonstrate nonlinear optical and piezoelectric effects. At elevated temperature, 140-180 °C, these native supramolecular structures (except for native Cyc-FF nanofibers) undergo an irreversible thermally induced transformation via reassembling into a completely new thermodynamically stable phase having nanowire morphology similar to those of amyloid fibrils. This reconstruction process is followed by deep and similar modification at all levels: macroscopic (morphology), molecular, peptide secondary, and electronic structures. However, original Cyc-FF nanofibers preserve their native physical properties. The self-fabricated supramolecular fibrillar ensembles exhibit the FTIR and CD signatures of new antiparallel β-sheet secondary folding with intermolecular hydrogen bonds and centrosymmetric structure. In this phase, the β-sheet nanofibers, irrespective of their native biomolecular origin, do not reveal nonlinear optical and piezoelectric effects, but do exhibit similar profound modification of optoelectronic properties followed by the appearance of visible (blue and green) photoluminescence (PL), which is not observed in the original peptides and their native nanostructures. The observed visible PL effect, ascribed to hydrogen bonds of thermally induced β-sheet secondary structures, has the same physical origin as that of the fluorescence found recently in amyloid fibrils and can be considered to be an optical signature of β-sheet structures in both biological and bioinspired

  3. Farnesol-modified biodegradable polyurethanes for cartilage tissue engineering.

    Science.gov (United States)

    Eglin, David; Grad, Sibylle; Gogolewski, Sylwester; Alini, Mauro

    2010-01-01

    A bifunctionalized 3,7,11-trimethyl-2,6,10-dodecatrien-1-diaminobutane amide (isoprenoid) was obtained from 3,7,11-trimethyl-2,6,10-dodecatrien-1-ol (farnesol) in a three-step synthesis. The bifunctionalized isoprenoid was characterized using infrared spectroscopy and (1)H and (13)C nuclear magnetic resonance spectroscopy and was covalently incorporated (0.12 mmol x g(-1)) into the biodegradable aliphatic polyurethane formed on the polycondensation reaction of poly(epsilon-caprolactone) diol, 1,4,3,6-dianhydro-D-sorbitol and 1,6-hexamethylene diisocyanate. Although the covalent incorporation of the isoprenoid molecule into the polyurethane chain modified the surface chemistry of the polymer, it did not affect the viability of attached chondrocytes. Porous 3D scaffolds were produced from the modified and unmodified biodegradable segmented polyurethanes by a salt leaching-phase-inverse technique. The scaffolds were seeded with bovine chondrocytes encapsulated in fibrin gel and cultured in vitro for 14 days. The incorporation of bifunctional isoprenoid into the polyurethane affected the morphology of the scaffolds produced, when compared with the morphology of the scaffolds produced using the same technique from the unmodified polyurethane. As a consequence, there was more uniform cell seeding and more homogeneous distribution of the synthesized extracellular matrix throughout the scaffold resulting in a reduced cell/tissue layer at the edges of the constructs. However, glycosaminoglycan (GAG), DNA content, and chondrocytes phenotype in the scaffolds produced from these two polyurethane formulations did not vary significantly. The findings suggest that the change of surface characteristics and the more open pore structure of the scaffolds produced from the isoprenoid-modified polyurethane are beneficial for the seeding efficiency and the homogeneity of the tissue engineered constructs. PMID:19191318

  4. Biodegradation of Spilled Diesel Fuel in Agricultural Soil: Effect of Humates, Zeolite, and Bioaugmentation

    Directory of Open Access Journals (Sweden)

    Pavel Kuráň

    2014-01-01

    Full Text Available Possible enhancement of biodegradation of petroleum hydrocarbons in agricultural soil after tank truck accident (~5000 mg/kg dry soil initial concentration by bioaugmentation of diesel degrading Pseudomonas fluorescens strain and addition of abiotic additives (humates, zeolite was studied in a 9-month pot experiment. The biodegradation process was followed by means of analytical parameters (hydrocarbon index expressed as content of C10–C40 aliphatic hydrocarbons, ratio pristane/C17, and total organic carbon content and characterization of soil microbial community (content of phospholipid fatty acids (PLFA as an indicator of living microbial biomass, respiration, and dehydrogenase activity. The concentration of petroleum hydrocarbons (C10–C40 was successfully reduced by ~60% in all 15 experiment variants. The bioaugmentation resulted in faster hydrocarbon elimination. On the contrary, the addition of humates and zeolite caused only a negligible increase in the degradation rate. These factors, however, affected significantly the amount of PLFA. The humates caused significantly faster increase of the total PLFA suggesting improvement of the soil microenvironment. Zeolite caused significantly slower increase of the total PLFA; nevertheless it aided in homogenization of the soil. Comparison of microbial activities and total PLFA revealed that only a small fraction of autochthonous microbes took part in the biodegradation which confirms that bioaugmentation was the most important treatment.

  5. Sustained Release of Antibacterial Lipopeptides from Biodegradable Polymers against Oral Pathogens.

    Science.gov (United States)

    Eckhard, Lea H; Houri-Haddad, Yael; Sol, Asaf; Zeharia, Rotem; Shai, Yechiel; Beyth, Shaul; Domb, Abraham J; Bachrach, Gilad; Beyth, Nurit

    2016-01-01

    The development of antibacterial drugs to overcome various pathogenic species, which inhabit the oral cavity, faces several challenges, such as salivary flow and enzymatic activity that restrict dosage retention. Owing to their amphipathic nature, antimicrobial peptides (AMPs) serve as the first line of defense of the innate immune system. The ability to synthesize different types of AMPs enables exploitation of their advantages as alternatives to antibiotics. Sustained release of AMPs incorporated in biodegradable polymers can be advantageous in maintaining high levels of the peptides. In this study, four potent ultra-short lipopeptides, conjugated to an aliphatic acid chain (16C) were incorporated in two different biodegradable polymers: poly (lactic acid co castor oil) (PLACO) and ricinoleic acid-based poly (ester-anhydride) (P(SA-RA)) for sustained release. The lipopeptide and polymer formulations were tested for antibacterial activity during one week, by turbidometric measurements of bacterial outgrowth, anti-biofilm activity by live/dead staining, biocompatibility by hemolysis and XTT colorimetric assays, mode of action by fluorescence-activated cell sorting (FACS) and release profile by a fluorometric assay. The results show that an antibacterial and anti-biofilm effect, as well as membrane disruption, can be achieved by the use of a formulation of lipopeptide incorporated in biodegradable polymer. PMID:27606830

  6. Impact of bioremediation treatments on the biodegradation of buried oil and predominant bacterial populations

    International Nuclear Information System (INIS)

    The feasibility of using mineral fertilizers as a bioremediation treatment for oil buried in fine sediments was tested in field trials at a site in the south-west of England. The plots were divided into three blocks of four treatments including untreated, fertilized, oiled unfertilized and oiled fertilized plots. The changes in residual hydrocarbons were monitored to study the biodegradation of Arabian Light Crude Oil which is known to have a high portion of biodegradable components. Samples were extracted at random points at intervals of 0, 42 and 101 days. The analysis process identified a range of aliphatic and aromatic hydrocarbons, as well as a range of geochemical biomarkers. The final results suggested that the oil in the fertilized plots was more degraded than in the oiled, unfertilized control plots. Three way, factorial analysis of variance was used to analyse the data from the oiled fertilized and oiled unfertilized plots. No significant effect of treatment on the degradation of aromatic hydrocarbons was observed. The results also showed that oil treatment and treatment with oil and fertilizer increased the abundance of hydrocarbon-degrading bacterial population. One significant observation was that different bacterial populations were stimulated in response to oil alone and a bioremediation treatment. It was concluded that the addition of inorganic fertilizers to the oiled oxic fine sediment substantially enhanced the level of biodegradation compared to untreated oiled sediment. Bioremediation is a feasible treatment for oil spills where the oil is buried in fine sediment. 14 refs., 1 tab., 4 figs

  7. Sustained Release of Antibacterial Lipopeptides from Biodegradable Polymers against Oral Pathogens

    Science.gov (United States)

    Eckhard, Lea H.; Houri-Haddad, Yael; Sol, Asaf; Zeharia, Rotem; Shai, Yechiel; Beyth, Shaul; Domb, Abraham J.

    2016-01-01

    The development of antibacterial drugs to overcome various pathogenic species, which inhabit the oral cavity, faces several challenges, such as salivary flow and enzymatic activity that restrict dosage retention. Owing to their amphipathic nature, antimicrobial peptides (AMPs) serve as the first line of defense of the innate immune system. The ability to synthesize different types of AMPs enables exploitation of their advantages as alternatives to antibiotics. Sustained release of AMPs incorporated in biodegradable polymers can be advantageous in maintaining high levels of the peptides. In this study, four potent ultra-short lipopeptides, conjugated to an aliphatic acid chain (16C) were incorporated in two different biodegradable polymers: poly (lactic acid co castor oil) (PLACO) and ricinoleic acid-based poly (ester-anhydride) (P(SA-RA)) for sustained release. The lipopeptide and polymer formulations were tested for antibacterial activity during one week, by turbidometric measurements of bacterial outgrowth, anti-biofilm activity by live/dead staining, biocompatibility by hemolysis and XTT colorimetric assays, mode of action by fluorescence-activated cell sorting (FACS) and release profile by a fluorometric assay. The results show that an antibacterial and anti-biofilm effect, as well as membrane disruption, can be achieved by the use of a formulation of lipopeptide incorporated in biodegradable polymer. PMID:27606830

  8. Biodegradable congress 2012; Bioschmierstoff-Kongress 2012

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-11-01

    Within the Guelzower expert discussions at 5th and 6th June, 2012 in Oberhausen (Federal Republic of Germany) the following lectures were held: (1) Promotion of biodegradable lubricants by means of research and development as well as public relations (Steffen Daebeler); (2) Biodegradable lubricants - An overview of the advantages and disadvantages of the engaged product groups (Hubertus Murrenhoff); (3) Standardization of biodegradable lubricants - CEN/DIN standard committees - state of the art (Rolf Luther); (4) Market research for the utilization of biodegradable lubricants and means of proof of sustainability (Norbert Schmitz); (5) Fields of application for high performance lubricants and requirements upon the products (Gunther Kraft); (6) Investigations of biodegradable lubricants in rolling bearings and gears (Christoph Hentschke); (7) Biodegradable lubricants in central lubrication systems Development of gears and bearings of offshore wind power installations (Reiner Wagner); (8) Investigations towards environmental compatibility of biodegradable lubricants used in offshore wind power installations (Tolf Schneider); (9) Development of glycerine based lubricants for the industrial metalworking (Harald Draeger); (10) Investigations and utilization of biodegradable oils as electroinsulation oils in transformers (Stefan Tenbohlen); (11) Operational behaviour of lubricant oils in vegetable oil operation and Biodiesel operation (Horst Hamdorf); (12) Lubrication effect of lubricating oil of the third generation (Stefan Heitzig); (13) Actual market development from the view of a producer of biodegradable lubricants (Frank Lewen); (14) Utilization of biodegradable lubricants in forestry harvesters (Guenther Weise); (15) New biodegradable lubricants based on high oleic sunflower oil (Otto Botz); (16) Integrated fluid concept - optimized technology and service package for users of biodegradable lubricants (Juergen Baer); (17) Utilization of a bio oil sensor to control

  9. Room temperature photoluminescence from nanostructured amorphous carbon

    OpenAIRE

    Henley, SJ; Carey, JD; Silva, SRP

    2004-01-01

    Visible room-temperature photoluminescence (PL) was observed from hydrogen-free nanostructured amorphous carbon films deposited by pulsed laser ablation in different background pressures of argon (PAr). By varying PAr from 5 to 340 mTorr, the film morphology changed from smooth to rough and at the highest pressures, low-density filamentary growth was observed. Over the same pressure regime an increase in the ordering of sp2 bonded C content was observed using visible Raman spectroscopy. Th...

  10. Ultraviolet photoluminescence of porous anodic alumina films

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Photoluminescence (PL) properties of porous anodic alumina (PAA) films prepared by using electrochemical anodization technique in a mixed solution of oxalic and sulfuric acid have been investigated. The PAA films have an intensive ultraviolet PL emission around 350 nm, of which a possible PL mechanism has been proposed. It was found that the incorporated oxalic ions, which could transform into PL centers and exist in the PAA films, are responsible for this ultraviolet PL emission.

  11. Infrared Spectroscopic Characterization of Photoluminescent Polymer Nanocomposites

    OpenAIRE

    Kyle Gipson; Kathryn Stevens; Phil Brown; John Ballato

    2015-01-01

    Organicallycoated inorganic nanoparticles were synthesized to produce photoluminescent nanocomposites based on a polymethyl methacrylate (PMMA) matrix. The nanoparticles comprised organic ligands (acetylsalicylic acid, ASA, and 2-picolinic acid, PA) attached to the lanthanum trifluoride (LaF3) host crystals that were doped with optically active terbium III (Tb3+) and synthesized using solution-based methods. The ligands were employed to functionalize the surface of Tb3+:LaF3 nanocrystals to ...

  12. Photoluminescent PEG based comacromers as excitation dependent fluorophores for biomedical applications.

    Science.gov (United States)

    Vijayan, Vineeth M; Komeri, Remya; Victor, Sunita P; Muthu, Jayabalan

    2015-11-01

    We report a novel multi-modal biodegradable photoluminescent comacromer [poly(propylene fumarate)-PEG-glycine] (PLM) having excitation-dependent fluorescence (EDF) for biomedical applications. The photoluminescence of the synthesized PLM in aqueous and solid state condition, fluorescence life time and photo stability were evaluated. Hydrogels and nanogels were prepared from the PLM by cross linking with acrylic acid. Nanogels exhibited spherical morphology with a particle size of 100 nm as evaluated by transmission electron microscopy (TEM). In vitro cytotoxic and hemolytic studies revealed cytocompatibility. Furthermore, cellular imaging of nanogels on L929 fibroblast and Hela cell lines revealed EDF characteristics. We hypothesize that the EDF characteristics of the synthesized PLM may be attributed to the presence of n-π* interactions of the hydroxyl oxygen atoms of PEG with carbonyl groups of the ester linkages. Taken together, our results indicate that the synthesized PEG-based comacromer can serve as biocompatible fluorophores for various biomedical applications. More importantly, the facile way of synthesizing fluorescent polymers based on PEG with EDF characteristics demonstrated in this work can pave the way for developing more novel biocompatible fluorophores with wide range of biomedical applications.

  13. Biodegradable Pectin/clay Aerogels

    Science.gov (United States)

    Biodegradable, foamlike materials based on renewable pectin and sodium montmorillonite clay were fabricated through a simple, environmentally friendly freeze-drying process. Addition of multivalent cations (Ca2+ and Al3+) resulted in apparent crosslinking of the polymer, and enhancement of aerogel p...

  14. Biodegradable polymeric prodrugs of naltrexone

    NARCIS (Netherlands)

    Bennet, D.B.; Li, X.; Adams, N.W.; Kim, S.W.; Hoes, C.J.T.; Feijen, J.

    1991-01-01

    The development of a biodegradable polymeric drug delivery system for the narcotic antagonist naltrexone may improve patient compliance in the treatment of opiate addiction. Random copolymers consisting of the ¿-amino acids N5-(3-hydroxypropyl--glutamine and -leucine were synthesized with equimolar

  15. Biodegradation kinetics at low concentrations (

    DEFF Research Database (Denmark)

    Toräng, Lars; Albrechtsen, Hans-Jørgen; Nyholm, Niels

    2000-01-01

    Aerobic biodegradation of 2,4-dichlorophenoxyacetic acid (2,4-D) was studied in groundwater added sediment fines. At concentrations at or below 1 mu g/L of 2,4-D degradation kinetic was of true first order without significant growth of specific degraders and with half-life for mineralization...

  16. Temperature-dependent photoluminescence of polyazomethine films

    International Nuclear Information System (INIS)

    We report absorption and first reliable photoluminescence (PL) studies at various temperatures on relatively thick films of the basic polyazomethine — PPI, i.e., poly(1,4-phenylene-methylidynenitrilo-1,4-phenylenenitrilomethylidine), prepared by chemical vapor deposition (CVD). Both absorption and PL spectra exhibit the vibronic progression due to the C–C stretching mode, characteristic for conjugated polymers. The absorption spectra appear to be practically temperature independent, in contrast to PL spectra, the intensity of which strongly decreases with increasing temperature. The origin of generally weak photoluminescence of PPI is suggested to be the result of a non-radiative electronic state occupied by the lone electron pair on the nitrogen orbital. - Highlights: ► First reliable observation of photoluminescence (PL) in polyazomethine (PPI). ► PL spectrum of PPI appears to be strongly temperature-dependent. ► Weak PL of PPI is a result of non-radiative state occupied by lone electron pair.

  17. A kinetic model for predicting biodegradation.

    Science.gov (United States)

    Dimitrov, S; Pavlov, T; Nedelcheva, D; Reuschenbach, P; Silvani, M; Bias, R; Comber, M; Low, L; Lee, C; Parkerton, T; Mekenyan, O

    2007-01-01

    Biodegradation plays a key role in the environmental risk assessment of organic chemicals. The need to assess biodegradability of a chemical for regulatory purposes supports the development of a model for predicting the extent of biodegradation at different time frames, in particular the extent of ultimate biodegradation within a '10 day window' criterion as well as estimating biodegradation half-lives. Conceptually this implies expressing the rate of catabolic transformations as a function of time. An attempt to correlate the kinetics of biodegradation with molecular structure of chemicals is presented. A simplified biodegradation kinetic model was formulated by combining the probabilistic approach of the original formulation of the CATABOL model with the assumption of first order kinetics of catabolic transformations. Nonlinear regression analysis was used to fit the model parameters to OECD 301F biodegradation kinetic data for a set of 208 chemicals. The new model allows the prediction of biodegradation multi-pathways, primary and ultimate half-lives and simulation of related kinetic biodegradation parameters such as biological oxygen demand (BOD), carbon dioxide production, and the nature and amount of metabolites as a function of time. The model may also be used for evaluating the OECD ready biodegradability potential of a chemical within the '10-day window' criterion.

  18. Shape memory polymers based on uniform aliphatic urethane networks

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, T S; Bearinger, J P; Herberg, J L; Marion III, J E; Wright, W J; Evans, C L; Maitland, D J

    2007-01-19

    Aliphatic urethane polymers have been synthesized and characterized, using monomers with high molecular symmetry, in order to form amorphous networks with very uniform supermolecular structures which can be used as photo-thermally actuable shape memory polymers (SMPs). The monomers used include hexamethylene diisocyanate (HDI), trimethylhexamethylenediamine (TMHDI), N,N,N{prime},N{prime}-tetrakis(hydroxypropyl)ethylenediamine (HPED), triethanolamine (TEA), and 1,3-butanediol (BD). The new polymers were characterized by solvent extraction, NMR, XPS, UV/VIS, DSC, DMTA, and tensile testing. The resulting polymers were found to be single phase amorphous networks with very high gel fraction, excellent optical clarity, and extremely sharp single glass transitions in the range of 34 to 153 C. Thermomechanical testing of these materials confirms their excellent shape memory behavior, high recovery force, and low mechanical hysteresis (especially on multiple cycles), effectively behaving as ideal elastomers above T{sub g}. We believe these materials represent a new and potentially important class of SMPs, and should be especially useful in applications such as biomedical microdevices.

  19. Quantification of biodegradable PLGA nanoparticles for drug targeting

    Directory of Open Access Journals (Sweden)

    Nadira Ibrišimović

    2010-11-01

    Full Text Available Objective. The aim of this work was the development of appropriate analytical methods and assays for determining and monitoring composition and degradation of nanoparticles built from PLGA (poly D, L-lactid-co-glycolid, which can be reloaded with different drugs. A sensitive and precise method for monitoring of nanoparticle degradation in vitro was developed and optimized. Nanoparticles allow a selective enrichment of different drugs and knowledge of the nature and type of their degradation is essential for characterization and control of drug release and dosage. Materials and methods. The first method developed during this work to quantify the PLGA polymer matrix use advantage of the chemical reaction of aliphatic carboxylic acids with ferric chloride (FeCl3 thus quantifying both degradation products of PLGA, lactic and glycol acids, at the same time. A second assay method of choice was to react to the polymer hydrolysate with lactate dehydrogenase, thus assaying selectively the lactic acid part. Results. During development of both of described methods was possible to determine dynamic range for PLGA matrix and nanoparticles, as well as to characterize impact of Pluronic F-68 and glycolic acid on lactate dehydrogenase activity. Conclusion. During our work we were able to develop two sensitive methods for monitoring of biodegradation of polymers which are consecutively used as a nanoparticle matrix in drug targeting.

  20. Project Summary. IN-SITU AQUIFER RESTORATION OF CHLORINATED ALIPHATICS BY METHANOTROPHIC BACTERIA

    Science.gov (United States)

    This project evaluated the potential of an innovative approach to aquifer restoration: enhanced in-situ biotransformation of chlorinated aliphatic solvents by a bacterial community grown on methane under aerobic conditions. The target chlorinated compounds were trichloroethene (...

  1. Fully Biobased Unsaturated Aliphatic Polyesters from Renewable Resources : Enzymatic Synthesis, Characterization, and Properties

    NARCIS (Netherlands)

    Jiang, Yi; Alberda van Ekenstein, Gerhard; Woortman, Albert J. J.; Loos, Katja

    2014-01-01

    Fully biobased saturated and unsaturated aliphatic polyesters and oligoesters are successfully prepared by Candida antarctica lipase B (CALB)-catalyzed polycondensations of succinate, itaconate, and 1,4-butanediol. The effects of monomer substrates and polymerization methods on enzymatic polycondens

  2. Thermally reversible thermoset materials based on the chemical modification of alternating aliphatic polyketones

    NARCIS (Netherlands)

    Araya Hermosilla, Rodrigo Andrés

    2016-01-01

    This thesis focused on the synthesis and characterization of different kinds of reversible thermosets and thermoset nanocomposite materials by using alternating aliphatic polyketone (PK) as raw material. Fundamental knowledge was generated regarding the molecular design of new polymers via chemical

  3. Calamistrin E, the First Annonaceous Acetogenin with Double Bond in Aliphatic Chain from Genus Uvaria

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Calamistrin E, the first Annonaceous acetogenin with C=C bond in the aliphatic chain from the genus Uvaria was isolated from U. calamistrata. Its structure including relative and absolute configurations was determined by chemical derivation and spectral analysis.

  4. Facile synthesis of aliphatic isothiocyanates and thioureas on solid phase using peptide coupling reagents

    DEFF Research Database (Denmark)

    Boas, Ulrik; Andersen, Heidi Gertz; Christensen, Jørn B.;

    2004-01-01

    Peptide coupling reagents can be used as versatile reagents for the formation of aliphatic isothiocyanates and thioureas on solid phase from the corresponding solid-phase anchored aliphatic primary amines. The formation of the thioureas is fast and highly chemoselective, and proceeds via formation...... of the intermediate isothiocyanate. The isothiocyanate and subsequent thiourea formation take place under standard peptide coupling conditions using carbon disulfide as the 'amino acid'. The thioureas are released from the resin and isolated in moderate to high yields....

  5. Generation of Microcellular Biodegradable Polycaprolactone Foams in Supercritical Carbon Dioxide

    Institute of Scientific and Technical Information of China (English)

    Xu Qun; Ren Xian-wen; Chang Yu-ning; Yu Long; Wang Jing-wu

    2004-01-01

    Present now the application of microcellular polymeric materials in biomedical field is growing rapidly, as that of guided tissue regeneration and cell transplantation. As far as guided tissue regeneration is concerned, porous implants are used as size selective membrane to promote the growth of a special tissue in a healing site. Ideally, the implant should be inherently biocompatible,have well-defined cell size and be resorbable with appropriate biodegradation rates.Poly(a-caprolactone) (PCL) is a kind of materials suit for the demands above. PCL is biocompatible and biodegradable aliphatic polyester which is nontoxic for living organisms and bioresorbable after a period of implantation. Because of its unique combination of biocompatibility, permeability and biodegradability, PCL and some of its copolymer with lactides and glycolide have been widely applied in medicine as artificial skin, artificial bone and containers for sustained drug release.Goel and Beckman have reported a new method to generate microcellular poly(methy l methacrylate) foams in which the samples are saturated with CO2 under a series of supercritical (SC)conditions, and then the system is rapidly depressurized to atmospheric pressure at constant temperature. Unlike traditional methods, it reduces glass-transition temperature (Tg) of the mixture to below the experimental temperature rather than directly heat the system above Tg. In this process of nucleation, no phase separation occurs as well as no phase boundary meets, so the cellular structure of the foam can be retained better.In this work, we have generated PCL foams by using supercritical CO2. Because of the low glass transition temperature (Tg = -60 ℃) of PCL far below the ice point, the experimental temperature in our study is much higher than Tg, which is different from the studies by others before. A series of variable factors on the foam structure as saturation temperature, saturation pressure, saturation time and depressurization

  6. On the Aliphatic versus Aromatic Content of the Carriers of the "Unidentified" Infrared Emission Features

    CERN Document Server

    Yang, Xuejuan; Li, Aigen; Zhong, Jianxin

    2016-01-01

    Although it is generally accepted that the so-called "unidentified" infrared emission (UIE) features at 3.3, 6.2, 7.7, 8.6, and 11.3 micrometer are characteristic of the stretching and bending vibrations of aromatic hydrocarbon materials, the exact nature of their carriers remains unknown: whether they are free-flying, predominantly aromatic gas-phase molecules, or amorphous solids with a mixed aromatic/aliphatic composition are being debated. Recently, the 3.3 and 3.4 micrometer features which are commonly respectively attributed to aromatic and aliphatic C-H stretches have been used to place an upper limit of ~2\\% on the aliphatic fraction of the UIE carriers (i.e. the number of C atoms in aliphatic chains to that in aromatic rings). Here we further explore the aliphatic versus aromatic content of the UIE carriers by examining the ratio of the observed intensity of the 6.2 micrometer aromatic C-C feature (I6.2) to that of the 6.85 micrometer aliphatic C-H deformation feature (I6.85). To derive the intrinsic...

  7. Synthesis of novel naphthoquinone aliphatic amides and esters and their anticancer evaluation.

    Science.gov (United States)

    Kongkathip, Boonsong; Akkarasamiyo, Sunisa; Hasitapan, Komkrit; Sittikul, Pichamon; Boonyalai, Nonlawat; Kongkathip, Ngampong

    2013-02-01

    Fourteen new naphthoquinone aliphatic amides and seventeen naphthoquinone aliphatic esters were synthesized in nine to ten steps from 1-hydroxy-2-naphthoic acid with 9-25% overall yield for the amides, and 16-21% overall yield for the esters. The key step of the amide synthesis is a coupling reaction between amine and various aliphatic acids using 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMTMM) as a coupling agent while for the ester synthesis, DCC/DMAP or CDI was used as the coupling reagent between aliphatic acids and naphthoquinone alcohol. Both naphthoquinone amides and esters were evaluated for their anticancer activity against KB cells. It was found that naphthoquinone aliphatic amides showed stronger anticancer activity than those of the esters when the chains are longer than 7-carbon atoms. The optimum chain of amides is expected to be 16-carbon atoms. In addition, naphthoquinone aliphatic esters with α-methyl on the ester moiety possessed much stronger anticancer activity than the straight chains. Decatenation assay revealed that naphthoquinone amide with 16-carbon atoms chain at 15 μM and 20 μM can completely inhibit hTopoIIα activity while at 10 μM the enzyme activity was moderately inhibited. Molecular docking result also showed the same trend as the cytotoxicity and decatenation assay. PMID:23313636

  8. Sources and distribution of aliphatic and polyaromatic hydrocarbons in sediments from the Neuquen River, Argentine Patagonia.

    Science.gov (United States)

    Monza, Liliana B; Loewy, Ruth M; Savini, Mónica C; Pechen de d'Angelo, Ana M

    2013-01-01

    Spatial distribution and probable sources of aliphatic and polyaromatic hydrocarbons (AHs, PAHs) were investigated in surface sediments collected along the bank of the Neuquen River, Argentina. Total concentrations of aliphatic hydrocarbons ranged between 0.41 and 125 μg/g dw. Six stations presented low values of resolved aliphatic hydrocarbons and the n-alkane distribution indexes applied suggested a clear biogenic source. These values can be considered the baseline levels of aliphatic hydrocarbons for the river sediments. This constitutes important information for the assessment of future impacts since a strong impulse in the exploitation of shale gas and shale oil in these zones is nowadays undergoing. For the other 11 stations, a mixture of aliphatic hydrocarbons of petrogenic and biogenic origin was observed. The spatial distribution reflects local inputs of these pollutants with a significant increase in concentrations in the lower course, where two major cities are located. The highest values of total aliphatic hydrocarbons were found in this sector which, in turn, was the only one where individual PAHs were detected.

  9. Photodegradation of major soil microbial biomolecules is comparable to biodegradation: Insights from infrared and diffusion editing NMR spectroscopies

    Science.gov (United States)

    Spence, Adrian; Kelleher, Brian P.

    2016-03-01

    As a primary decomposition process in terrestrial biosystems, biodegradation has been extensively studied with regard to its impact on soil organic matter transformation. However, the biotransformation of soil microbial biomass (a primary source of soil organic carbon) remains poorly understood, and even less is known about the fate of microbial-derived carbon under photodegradation. Here, we combine infrared and diffusion editing NMR spectroscopies to provide molecular-level information on the photodegradation of major biochemical components in soil microbial biomass and leachates over time. Results indicate a considerable enrichment in aliphatic components, presumably polymethylenic-C [(C-H2)n] and the simultaneous loss of carbohydrate and protein structures in the biomass. An immediate conclusion is that photodegradation increased the conversion of macromolecular carbohydrates and proteins to smaller components. However, further analysis reveals that macromolecular carbohydrates and proteins may be more resistant to photodegradation than initially thought and are found in the leachates. Although attenuated, there is also evidence to suggest that some aliphatic structures persist in the leachates. Overall, the photodegradation pathway reported here is remarkably similar to that of biodegradation, suggesting that under rapidly expanding anthropogenic land disturbances, photodegradation could be an important driver of the transformation of microbial-derived organic matter in terrestrial biosystems.

  10. Enhancement of carbon nanotube photoluminescence by photonic crystal nanocavities

    OpenAIRE

    Watahiki, R.; Shimada, T; Zhao, P; Chiashi, S.; Iwamoto, S.; Arakawa, Y; Maruyama, S.; Kato, Y. K.

    2012-01-01

    Photonic crystal nanocavities are used to enhance photoluminescence from single-walled carbon nanotubes. Micelle-encapsulated nanotubes are deposited on nanocavities within Si photonic crystal slabs and confocal microscopy is used to characterize the devices. Photoluminescence spectra and images reveal nanotube emission coupled to nanocavity modes. The cavity modes can be tuned throughout the emission wavelengths of carbon nanotubes, demonstrating the ability to enhance photoluminescence from...

  11. Aliphatic polyester block polymers: renewable, degradable, and sustainable.

    Science.gov (United States)

    Hillmyer, Marc A; Tolman, William B

    2014-08-19

    Nearly all polymers are derived from nonrenewable fossil resources, and their disposal at their end of use presents significant environmental problems. Nonetheless, polymers are ubiquitous, key components in myriad technologies and are simply indispensible for modern society. An important overarching goal in contemporary polymer research is to develop sustainable alternatives to "petro-polymers" that have competitive performance properties and price, are derived from renewable resources, and may be easily and safely recycled or degraded. Aliphatic polyesters are particularly attractive targets that may be prepared in highly controlled fashion by ring-opening polymerization of bioderived lactones. However, property profiles of polyesters derived from single monomers (homopolymers) can limit their applications, thus demanding alternative strategies. One such strategy is to link distinct polymeric segments in an A-B-A fashion, with A and B chosen to be thermodynamically incompatible so that they can self-organize on a nanometer-length scale and adopt morphologies that endow them with tunable properties. For example, such triblock copolymers can be useful as thermoplastic elastomers, in pressure sensitive adhesive formulations, and as toughening modifiers. Inspired by the tremendous utility of petroleum-derived styrenic triblock copolymers, we aimed to develop syntheses and understand the structure-property profiles of sustainable alternatives, focusing on all renewable and all readily degradable aliphatic polyester triblocks as targets. Building upon oxidation chemistry reported more than a century ago, a constituent of the peppermint plant, (-)-menthol, was converted to the ε-caprolactone derivative menthide. Using a diol initiator and controlled catalysis, menthide was polymerized to yield a low glass transition temperature telechelic polymer (PM) that was then further functionalized using the biomass-derived monomer lactide (LA) to yield fully renewable PLA

  12. Pharmacological activities of cilantro's aliphatic aldehydes against Leishmania donovani.

    Science.gov (United States)

    Donega, Mateus A; Mello, Simone C; Moraes, Rita M; Jain, Surendra K; Tekwani, Babu L; Cantrell, Charles L

    2014-12-01

    Leishmaniasis is a chronic infectious disease caused by different Leishmania species. Global occurrences of this disease are primarily limited to tropical and subtropical regions. Treatments are available; however, patients complain of side effects. Different species of plants have been screened as a potential source of new drugs against leishmaniasis. In this study, we investigated the antileishmanial activity of cilantro (Coriandrum sativum) essential oil and its main components: (E)-2-undecenal, (E)-2-decenal, (E)-2-dodecenal, decanal, dodecanal, and tetradecanal. The essential oil of C. sativum leaves inhibits growth of Leishmani donovani promastigotes in culture with an IC50 of 26.58 ± 6.11 µg/mL. The aliphatic aldehydes (E)-2-decenal (7.85 ± 0.28 µg/mL), (E)-2-undecenal (2.81 ± 0.21 µg/mL), and (E)-2-dodecenal (4.35 ± 0.15 µg/mL), all isolated from C. sativum essential oil, are effective inhibitors of in vitro cultures of L. donovani promastigotes. Aldehydes (E)-2-decenal, (E)-2-undecenal, and (E)-2-dodecenal were also evaluated against axenic amastigotes and IC50 values were determined to be 2.47 ± 0.25 µg/mL, 1.25 ± 0.11 µg/mL, and 4.78 ± 1.12 µg/mL, respectively. (E)-2-Undecenal and (E)-2-dodecenal demonstrated IC50 values of 5.65 ± 0.19 µg/mL and 9.60 ± 0.89 µg/mL, respectively, against macrophage amastigotes. These cilantro compounds showed no cytotoxicity against THP-1 macrophages. PMID:25340465

  13. Secondary aerosol formation from atmospheric reactions of aliphatic amines

    Directory of Open Access Journals (Sweden)

    S. M. Murphy

    2007-01-01

    Full Text Available Although aliphatic amines have been detected in both urban and rural atmospheric aerosols, little is known about the chemistry leading to particle formation or the potential aerosol yields from reactions of gas-phase amines. We present here the first systematic study of aerosol formation from the atmospheric reactions of amines. Based on laboratory chamber experiments and theoretical calculations, we evaluate aerosol formation from reaction of OH, ozone, and nitric acid with trimethylamine, methylamine, triethylamine, diethylamine, ethylamine, and ethanolamine. Entropies of formation for alkylammonium nitrate salts are estimated by molecular dynamics calculations enabling us to estimate equilibrium constants for the reactions of amines with nitric acid. Though subject to significant uncertainty, the calculated dissociation equilibrium constant for diethylammonium nitrate is found to be sufficiently small to allow for its atmospheric formation, even in the presence of ammonia which competes for available nitric acid. Experimental chamber studies indicate that the dissociation equilibrium constant for triethylammonium nitrate is of the same order of magnitude as that for ammonium nitrate. All amines studied form aerosol when photooxidized in the presence of NOx with the majority of the aerosol mass present at the peak of aerosol growth consisting of aminium (R3NH+ nitrate salts, which repartition back to the gas phase as the parent amine is consumed. Only the two tertiary amines studied, trimethylamine and triethylamine, are found to form significant non-salt organic aerosol when oxidized by OH or ozone; calculated organic mass yields for the experiments conducted are similar for ozonolysis (15% and 5% respectively and photooxidation (23% and 8% respectively. The non-salt organic aerosol formed appears to be more stable than the nitrate salts and does not quickly repartition back to the gas phase.

  14. BIODEGRADABLE COATING FROM AGATHIS ALBA

    Directory of Open Access Journals (Sweden)

    NORYAWATI MULYONO

    2012-11-01

    Full Text Available The adhesive property of copal makes it as a potential coating onto aluminum foil to replace polyethylene. This research aimed to develop copal-based coating. The coating was prepared by extracting the copal in ethyl acetate and dipping the aluminium foil in ethyl acetate soluble extract of copal. The characterization of coating included its thickness, weight, thermal and chemical resistance, and biodegradation. The results showed that the coating thickness and weight increased as the copal concentration and dipping frequency increased. Thermal resistance test showed that the coating melted after being heated at 110°C for 30 min. Copal-based coating wasresistant to acidic solution (pH 4.0, water, and coconut oil, but was deteriorated in detergent 1% (w/v and basic solution (pH 10.0. Biodegradability test using Pseudomonas aeruginosa showed weight reduction of 76.82% in 30 days.

  15. Biodegradation of Polycyclic Aromatic Hydrocarbons

    OpenAIRE

    DEMİR, İsmail; DEMİRBAĞ, Zihni

    1999-01-01

    Polycylic aromatic hydrocarbons (PAHs), such as petroleum and petroleum derivatives, are widespread organic pollutants entering the environment, chiefly, through oil spills and incomplete combustion of fossil fuels. Since most PAHs are persist in the environment for a long period of time and bioaccumulate, they cause environmental pollution and effect biological equilibrium dramatically. Biodegradation of some PAHs by microorganisms has been biochemically and genetically investigated. Ge...

  16. ELECTRICAL PROPERTIES AND PHOTOLUMINESCENCE OF AMORPHOUS SILICON

    OpenAIRE

    Liao, X.; Kong, G.; X. Yang; Wang, P.; Chao, Y.; Chen, Z.; Liu, C

    1981-01-01

    The temperature dependence of conductivity, photoluminescence and ion-implantation doping effect of glow discharge (GD) and low pressure CVD a-Si films have been investigated. Post-hydrogenation significantly reduces the gap state density of LPCVD a-Si. Phosphorus and boron ion-implantation show that LPCVD a-Si has a higher doping efficiency than GD samples, reaching a maximum R.T. conductivity of 0.3 Ω-1 cm-1. Two peaks were observed in the luminescence spectrum of GD a-Si films and the orig...

  17. Photoluminescence from doped ZnS nanostructures

    Science.gov (United States)

    Karar, N.

    2007-05-01

    Photoluminescence (PL) properties of differently doped nanocrystalline ZnS encapsulated by ZnO (ZnS/ZnO) are reported. It is found that in all cases aluminium as an extra/additional dopant leads to PL enhancement. In comparison to reported blue emitting bulk ZnS:Ag, or green emitting bulk ZnS:Cu, our nanocrystalline samples show a different PL emission profile. This observation is attributed to nanogranule formation, different dopant levels and ZnO capping related energy level modifications.

  18. Photoluminescence of trypsin after UV-irradiation

    International Nuclear Information System (INIS)

    For study purposes of the primary effects of UV light the photoluminescence of trypsin was investigated before and after UV irradiation (lambda = 254 nm). The results were compared with the corresponding relations at equimolar mixtures of the constituent amino acids. The increase of the absorption in the region between 230 nm and 400 nm at UV irradiation of trypsin in aqueous solution is primarily attributed to the ionization of tyrosine. The fluorescence is strongly quenched mainly due to the ionized tyrosine residues. The results are discussed in connection with previous investigations on radical formation and inactivation of trypsin after UV irradiation. (orig.)

  19. Gold Photoluminescence Wavelength and Polarization Engineering

    CERN Document Server

    Andersen, Sebastian K H; Bozhevolnyi, Sergey I

    2016-01-01

    We demonstrate engineering of the spectral content and polarization of photoluminescence (PL) from arrayed gold nanoparticles atop a subwavelength-thin dielectric spacer and optically-thick gold film, a configuration that supports gap-surface plasmon resonances (GSPRs). Choice of shapes and dimensions of gold nanoparticles influences the GSPR wavelength and polarization characteristics, thereby allowing us to enhance and spectrally mold the plasmon-assisted PL while simultaneously controlling its polarization. In order to understand the underlying physics behind the plasmon-enhanced PL, we develop a simple model that faithfully reproduces all features observed in our experiments showing also good quantitative agreement for the PL enhancement

  20. Gold Photoluminescence: Wavelength and Polarization Engineering

    DEFF Research Database (Denmark)

    Andersen, Sebastian Kim Hjælm; Pors, Anders Lambertus; Bozhevolnyi, Sergey I.

    2015-01-01

    and dimensions of gold nanoparticles influences the GSPR wavelength and polarization characteristics, thereby allowing us to enhance and spectrally mold the plasmon-assisted PL while simultaneously controlling its polarization. In order to understand the underlying physics behind the plasmon-enhanced PL, we......We demonstrate engineering of the spectral content and polarization of photoluminescence (PL) from arrayed gold nanoparticles atop a subwavelength-thin dielectric spacer and optically-thick gold film, a configuration that supports gap-surface plasmon resonances (GSPRs). Choice of shapes...

  1. Engineering Flame Retardant Biodegradable Nanocomposites

    Science.gov (United States)

    He, Shan; Yang, Kai; Guo, Yichen; Zhang, Linxi; Pack, Seongchan; Davis, Rachel; Lewin, Menahem; Ade, Harald; Korach, Chad; Kashiwagi, Takashi; Rafailovich, Miriam

    2013-03-01

    Cellulose-based PLA/PBAT polymer blends can potentially be a promising class of biodegradable nanocomposites. Adding cellulose fiber reinforcement can improve mechanical properties of biodegradable plastics, but homogeneously dispersing hydrophilic cellulose in the hydrophobic polymer matrix poses a significant challenge. We here show that resorcinol diphenyl phosphates (RDP) can be used to modify the surface energy, not only reducing phase separation between two polymer kinds but also allowing the cellulose particles and the Halloysite clay to be easily dispersed within polymer matrices to achieve synergy effect using melt blending. Here in this study we describe the use of cellulose fiber and Halloysite clay, coated with RDP surfactant, in producing the flame retardant polymer blends of PBAT(Ecoflex) and PLA which can pass the stringent UL-94 V0 test. We also utilized FTIR, SEM and AFM nanoindentation to elucidate the role RDP plays in improving the compatibility of biodegradable polymers, and to determine structure property of chars that resulted in composites that could have optimized mechanical and thermal properties. Supported by Garcia Polymer Center and NSF Foundation.

  2. Alteration in cell surface properties of Burkholderia spp. during surfactant-aided biodegradation of petroleum hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Mohanty, Sagarika; Mukherji, Suparna [Indian Institute of Technology Bombay, Mumbai (India). Centre for Environmental Science and Engineering (CESE)

    2012-04-15

    Chemical surfactants may impact microbial cell surface properties, i.e., cell surface hydrophobicity (CSH) and cell surface charge, and may thus affect the uptake of components from non-aqueous phase liquids (NAPLs). This work explored the impact of Triton X-100, Igepal CA 630, and Tween 80 (at twice the critical micelle concentration, CMC) on the cell surface characteristics of Burkholderia cultures, Burkholderia cepacia (ES1, aliphatic degrader) and Burkholderia multivorans (NG1, aromatic degrader), when grown on a six-component model NAPL. In the presence of Triton X-100, NAPL biodegradation was enhanced from 21% to 60% in B. cepacia and from 18% to 53% in B. multivorans. CSH based on water contact angle (50-52 ) was in the same range for both strains while zeta potential at neutral pH was -38 and -31 mV for B. cepacia and B. multivorans, respectively. In the presence of Triton X-100, their CSH increased to greater than 75 and the zeta potential decreased. This induced a change in the mode of uptake and initiated aliphatic hydrocarbon degradation by B. multivorans and increased the rate of aliphatic hydrocarbon degradation in B. cepacia. Igepal CA 630 and Tween 80 also altered the cell surface properties. For B. cepacia grown in the presence of Triton X-100 at two and five times its CMC, CSH increased significantly in the log growth phase. Growth in the presence of the chemical surfactants also affected the abundance of chemical functional groups on the cell surface. Cell surface changes had maximum impact on NAPL degradation in the presence of emulsifying surfactants, Triton X-100 and Igepal CA630.

  3. Insights into the biodegradation of weathered hydrocarbons in contaminated soils by bioaugmentation and nutrient stimulation.

    Science.gov (United States)

    Jiang, Ying; Brassington, Kirsty J; Prpich, George; Paton, Graeme I; Semple, Kirk T; Pollard, Simon J T; Coulon, Frédéric

    2016-10-01

    The potential for biotransformation of weathered hydrocarbon residues in soils collected from two commercial oil refinery sites (Soil A and B) was studied in microcosm experiments. Soil A has previously been subjected to on-site bioremediation and it was believed that no further degradation was possible while soil B has not been subjected to any treatment. A number of amendment strategies including bioaugmentation with hydrocarbon degrader, biostimulation with nutrients and soil grinding, were applied to the microcosms as putative biodegradation improvement strategies. The hydrocarbon concentrations in each amendment group were monitored throughout 112 days incubation. Microcosms treated with biostimulation (BS) and biostimulation/bioaugmentation (BS + BA) showed the most significant reductions in the aliphatic and aromatic hydrocarbon fractions. However, soil grinding was shown to reduce the effectiveness of a nutrient treatment on the extent of biotransformation by up to 25% and 20% for the aliphatic and aromatic hydrocarbon fractions, respectively. This is likely due to the disruption to the indigenous microbial community in the soil caused by grinding. Further, ecotoxicological responses (mustard seed germination and Microtox assays) showed that a reduction of total petroleum hydrocarbon (TPH) concentration in soil was not directly correlable to reduction in toxicity; thus monitoring TPH alone is not sufficient for assessing the environmental risk of a contaminated site after remediation.

  4. Histological evaluation of different biodegradable and non-biodegradable membranes implanted subcutaneously in rats

    DEFF Research Database (Denmark)

    Zhao, S; Pinholt, E M; Madsen, J E;

    2000-01-01

    Different types of biodegradable membranes have become available for guided tissue regeneration. The purpose of this study was to evaluate histologically three different biodegradable membranes (Bio-Gide, Resolut and Vicryl) and one non-biodegradable membrane (expanded polytetrafluoroethylene/e-P...

  5. Strong white photoluminescence from annealed zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Zhenhua, E-mail: baizh46@gmail.com [School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637457 (Singapore); Fujii, Minoru; Imakita, Kenji; Hayashi, Shinji [Department of Electrical and Electronic Engineering, Graduate School of Engineering, Kobe University, Rokkodai, Nada, Kobe 657-8501 (Japan)

    2014-01-15

    The optical properties of zeolites annealed at various temperatures are investigated for the first time. The annealed zeolites exhibit strong white photoluminescence (PL) under ultraviolet light excitation. With increasing annealing temperature, the emission intensity of annealed zeolites first increases and then decreases. At the same time, the PL peak red-shifts from 495 nm to 530 nm, and then returns to 500 nm. The strongest emission appears when the annealing temperature is 500 °C. The quantum yield of the sample is measured to be ∼10%. The PL lifetime monotonously increases from 223 μs to 251 μs with increasing annealing temperature. The origin of white PL is ascribed to oxygen vacancies formed during the annealing process. -- Highlights: • The optical properties of zeolites annealed at various temperatures are investigated. • The annealed zeolites exhibit strong white photoluminescence. • The maximum PL enhancement reaches as large as 62 times. • The lifetime shows little dependence on annealing temperature. • The origin of white emission is ascribed to the oxygen vacancies.

  6. Photoluminescence in MgIn2S4 spinel crystals

    International Nuclear Information System (INIS)

    The ingot of MgIn2S4 with a spinel structure was synthesized. The photoluminescence of this semiconductor material was studied at room temperature. The bell-shaped photoluminescence spectra with peaks at 1.35 and 1.49 eV were observed; their possible interpretation is suggested. (authors)

  7. CZE study on adsorption processes of aliphatic and aromatic amines on PMMA chip.

    Science.gov (United States)

    Masár, Marián; Kruk, Pavol; Luc, Milan; Bodor, Róbert; Danč, Ladislav; Troška, Peter

    2013-02-01

    Adsorption processes on a PMMA chip linked with CZE separations of a group of 13 aliphatic and aromatic mono- and di-amines were studied. Due to the lack of chromophores within aliphatic amines, contact conductivity detection implemented directly onto the chip was used for monitoring of cationic CZE separations. To prevent an adsorption of studied amines to the chip channels, the surface of PMMA chip was modified by dynamic coating. Different surface modifiers, such as aliphatic oligoamines (diethylenetriamine and triethylenetetramine), were added to the BGE solutions filling the chip channels. The effect of various concentrations of surface modifiers on peak profiles and separation parameters of amines was monitored. Of these, mainly, aliphatic di-amines and aromatic mono-amines adversely affected the CZE resolution of a whole group of analytes by their strong adsorption to the chip channels. A propionate BGE with pH 3.2 containing 100 μM triethylenetetramine and 25 mM 18-crown-6-ether was found suitable for CZE resolution of 12 from a total of 13 amines studied. Simple dynamic modification of the surface of PMMA chip enabled fast (analysis time lasted 9 min), sensitive (sub-μM LODs reached) and reproducible (1-3% RSD of the peak areas) CZE analysis of the aliphatic and aromatic amines.

  8. Photoluminescence in amorphous MgSiO_3 silicate

    CERN Document Server

    Thompson, S P; Day, S J; Connor, L D; Evans, A

    2013-01-01

    Samples of amorphous MgSiO_3 annealed at temperature steps leading up to their crystallisation temperature show a rise in photoluminescence activity, peaking at ~450C. The photoluminescence band has a main peak at 595nm and a weaker peak at 624nm. We present laboratory data to show that the maximum in photoluminescence activity is related to substantial structural reordering that occurs within a relatively narrow temperature range. We attribute the origin of the photoluminescence to non-bridging oxygen hole centre defects, which form around ordered nano-sized domain structures as a result of the breakup of tetrahedral connectivity in the disordered inter-domain network, aided by the loss of bonded OH. These defects are removed as crystallisation progresses, resulting in the decrease and eventual loss of photoluminescence. Thermally processed hydrogenated amorphous silicate grains could therefore represent a potential carrier of extended red emission.

  9. Here today, gone tomorrow: biodegradable soft robots

    Science.gov (United States)

    Rossiter, Jonathan; Winfield, Jonathan; Ieropoulos, Ioannis

    2016-04-01

    One of the greatest challenges to modern technologies is what to do with them when they go irreparably wrong or come to the end of their productive lives. The convention, since the development of modern civilisation, is to discard a broken item and then procure a new one. In the 20th century enlightened environmentalists campaigned for recycling and reuse (R and R). R and R has continued to be an important part of new technology development, but there is still a huge problem of non-recyclable materials being dumped into landfill and being discarded in the environment. The challenge is even greater for robotics, a field which will impact on all aspects of our lives, where discards include motors, rigid elements and toxic power supplies and batteries. One novel solution is the biodegradable robot, an active physical machine that is composed of biodegradable materials and which degrades to nothing when released into the environment. In this paper we examine the potential and realities of biodegradable robotics, consider novel solutions to core components such as sensors, actuators and energy scavenging, and give examples of biodegradable robotics fabricated from everyday, and not so common, biodegradable electroactive materials. The realisation of truly biodegradable robots also brings entirely new deployment, exploration and bio-remediation capabilities: why track and recover a few large non-biodegradable robots when you could speculatively release millions of biodegradable robots instead? We will consider some of these exciting developments and explore the future of this new field.

  10. Nylon biodegradation by lignin-degrading fungi.

    OpenAIRE

    DEGUCHI, T; Kakezawa, M; Nishida, T.

    1997-01-01

    The biodegradation of nylon by lignin-degrading fungi was investigated. The fungus IZU-154 significantly degraded nylon-66 membrane under ligninolytic conditions. Nuclear magnetic resonance analysis showed that four end groups, CHO, NHCHO, CH3, and CONH2, were formed in the biodegraded nylon-66 membranes, suggesting that nylon-66 was degraded oxidatively.

  11. Systematic safety evaluation on photoluminescent carbon dots

    Science.gov (United States)

    Wang, Kan; Gao, Zhongcai; Gao, Guo; Wo, Yan; Wang, Yuxia; Shen, Guangxia; Cui, Daxiang

    2013-03-01

    Photoluminescent carbon dots (C-dots) were prepared using the improved nitric acid oxidation method. The C-dots were characterized by tapping-mode atomic force microscopy, and UV-vis absorption spectroscopy. The C-dots were subjected to systematic safety evaluation via acute toxicity, subacute toxicity, and genotoxicity experiments (including mouse bone marrow micronuclear test and Salmonella typhimurium mutagenicity test). The results showed that the C-dots were successfully prepared with good stability, high dispersibility, and water solubility. At all studied C-dot dosages, no significant toxic effect, i.e., no abnormality or lesion, was observed in the organs of the animals. Therefore, the C-dots are non-toxic to mice under any dose and have potential use in fluorescence imaging in vivo, tumor cell tracking, and others.

  12. Modelling absorption and photoluminescence of TPD

    Energy Technology Data Exchange (ETDEWEB)

    Vragovic, Igor [Dpto. de Fisica Aplicada and Inst. Universitario de Materiales de Alicante, Universidad de Alicante, E-03080 Alicante (Spain)], E-mail: igor.vragovic@ua.es; Calzado, Eva M.; Diaz Garcia, Maria A.; Himcinschi, C. [Max-Planck-Institut fuer Mikrostrukturphysik, D-06120 Halle (Germany); Gisslen, L.; Scholz, R. [Walter Schottky Institut, Technische Universitaet Muenchen, D-85748 Garching (Germany)

    2008-05-15

    We analyse the optical spectra of N,N{sup '}-diphenyl-N,N{sup '}-bis(3-methyl-phenyl)-(1,1{sup '}-biphenyl)-4,4{sup '}-diamine (TPD) doped polystyrene films. The aim of the present paper is to give a microscopic interpretation of the significant Stokes shift between absorption and photoluminescence, which makes this material suitable for stimulated emission. The optimized geometric structures and energies of a neutral TPD monomer in ground and excited states are obtained by ab initio calculations using Hartree-Fock and density functional theory. The results indicate that the second distinct peak observed in absorption may arise either from a group of higher electronic transitions of the monomer or from the lowest optical transitions of a TPD dimer.

  13. Photoluminescence studies in epitaxial CZTSe thin films

    Science.gov (United States)

    Sendler, Jan; Thevenin, Maxime; Werner, Florian; Redinger, Alex; Li, Shuyi; Hägglund, Carl; Platzer-Björkman, Charlotte; Siebentritt, Susanne

    2016-09-01

    Epitaxial Cu 2 ZnSnSe 4 (CZTSe) thin films were grown by molecular beam epitaxy on GaAs(001) using two different growth processes, one containing an in-situ annealing stage as used for solar cell absorbers and one for which this step was omitted. Photoluminescences (PL) measurements carried out on these samples show no dependence of the emission shape on the excitation intensity at different temperatures ranging from 4 K to 300 K . To describe the PL measurements, we employ a model with fluctuating band edges in which the density of states of the resulting tail states does not seem to depend on the excited charge carrier density. In this interpretation, the PL measurements show that the annealing stage removes a defect level, which is present in the samples without this annealing.

  14. Temperature-Dependent Photoluminescence of Graphene Oxide

    Science.gov (United States)

    Jadhav, S. T.; Rajoba, S. J.; Patil, S. A.; Han, S. H.; Jadhav, L. D.

    2016-01-01

    Graphene oxide thin films have been deposited by spray pyrolysis using graphene oxide powder prepared by modified Hummers method. These thin films were characterized by different physico-chemical techniques. The x-ray diffraction studies revealed the structural properties of GO (graphene oxide) while the Raman spectrum showed the presence of D and G and two-dimensional bands. The D/G intensity ratio for spray-deposited GO film is 1.10. The x-ray photoelectron spectroscopy showed 67% and 33% atomic percentages of carbon and oxygen, respectively. The ratio of O1s/C1s was found to be 0.49. The temperature-dependent photoluminescence of GO thin film and GO solution showed a blue emission.

  15. Biodegradation and toxicological evaluation of lubricant oils

    Directory of Open Access Journals (Sweden)

    Ivo Shodji Tamada

    2012-12-01

    Full Text Available The aim of this work was to compare different toxicity levels of lubricant oils. The tests were performed using the earthworm (Eisenia andrei, arugula seeds (Eruca sativa and lettuce seeds (Lactuca sativa, with three types of contaminants (mineral lubricant oil, synthetic lubricant oil and used lubricant oil for various biodegradation periods in the soil. The toxicity tests indirectly measured the biodegradation of the contaminants. The samples were analyzed at t0, t60, t120 and t180 days of biodegradation. The used lubricant oil was proved very toxic in all the tests and even after biodegradation its toxicity was high. The mineral and synthetic oils were biodegraded efficiently in the soil although their toxicity did not disappear completely after 180 days.

  16. ORGANIC CHEMISTRY. Catalytic asymmetric hydroamination of unactivated internal olefins to aliphatic amines.

    Science.gov (United States)

    Yang, Yang; Shi, Shi-Liang; Niu, Dawen; Liu, Peng; Buchwald, Stephen L

    2015-07-01

    Catalytic assembly of enantiopure aliphatic amines from abundant and readily available precursors has long been recognized as a paramount challenge in synthetic chemistry. Here, we describe a mild and general copper-catalyzed hydroamination that effectively converts unactivated internal olefins—an important yet unexploited class of abundant feedstock chemicals—into highly enantioenriched α-branched amines (≥96% enantiomeric excess) featuring two minimally differentiated aliphatic substituents. This method provides a powerful means to access a broad range of advanced, highly functionalized enantioenriched amines of interest in pharmaceutical research and other areas.

  17. On the aliphatic versus aromatic content of the carriers of the `unidentified' infrared emission features

    Science.gov (United States)

    Yang, X. J.; Glaser, R.; Li, Aigen; Zhong, J. X.

    2016-10-01

    Although it is generally accepted that the unidentified infrared emission (UIE) features at 3.3, 6.2, 7.7, 8.6, and 11.3 μm are characteristic of the stretching and bending vibrations of aromatic hydrocarbon materials, the exact nature of their carriers remains unknown: whether they are free-flying, predominantly aromatic gas-phase molecules, or amorphous solids with a mixed aromatic/aliphatic composition are being debated. Recently, the 3.3 and 3.4 μm features which are commonly respectively attributed to aromatic and aliphatic C-H stretches have been used to place an upper limit of ˜2 per cent on the aliphatic fraction of the UIE carriers (i.e. the number of C atoms in aliphatic chains to that in aromatic rings). Here we further explore the aliphatic versus aromatic content of the UIE carriers by examining the ratio of the observed intensity of the 6.2 μm aromatic C-C feature (I6.2) to that of the 6.85 μm aliphatic C-H deformation feature (I6.85). To derive the intrinsic oscillator strengths of the 6.2 μm stretch (A6.2) and the 6.85 μm deformation (A6.85), we employ density functional theory to compute the vibrational spectra of seven methylated polycyclic aromatic hydrocarbon molecules and their cations. By comparing I6.85/I6.2 with A6.85/A6.2, we derive the fraction of C atoms in methyl(ene) aliphatic form to be at most ˜10 per cent, confirming the earlier finding that the UIE emitters are predominantly aromatic. We have also computed the intrinsic strength of the 7.25 μm feature (A7.25), another aliphatic C-H deformation band. We find that A6.85 appreciably exceeds A7.25. This explains why the 6.85 μm feature is more frequently detected in space than the 7.25 μm feature.

  18. Aliphatic and aromatic hydrocarbons in Candiota coal samples: novel series of bicyclic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Miranda, A.C.M.L.; Loureiro, M.R.B.; Cardoso, J.N. [Universidade Federal do Rio de Janeiro, Rio de Janeiro (Brazil). Inst. de Quimica

    1999-07-01

    Gas chromatography - mass spectrometry was used to analyse aliphatic and aromatic fractions obtained from nine samples taken from two different seams of five boreholes in the Candiota coalfield (Lower Permian). The occurrence of certain tetracyclic diterpenoids among the aliphatic hydrocarbons, and the tricyclic diterpenoids simonellite and retene in the aromatic hydrocarbon concentrates, suggest an important input from conifers to the sedimentary biomass. This may explain the origin of a novel series of saturated and aromatic bicyclic compounds detected in the extracts which may be structurally related to the same precursor, possibly a conifer resin-derived tricyclic diterpenoid.

  19. Biodegradable products by lipase biocatalysis.

    Science.gov (United States)

    Linko, Y Y; Lämsä, M; Wu, X; Uosukainen, E; Seppälä, J; Linko, P

    1998-11-18

    The interest in the applications of biocatalysis in organic syntheses has rapidly increased. In this context, lipases have recently become one of the most studied groups of enzymes. We have demonstrated that lipases can be used as biocatalyst in the production of useful biodegradable compounds. A number of examples are given. 1-Butyl oleate was produced by direct esterification of butanol and oleic acid to decrease the viscosity of biodiesel in winter use. Enzymic alcoholysis of vegetable oils without additional organic solvent has been little investigated. We have shown that a mixture of 2-ethyl-1-hexyl esters can be obtained in a good yield by enzymic transesterification from rapeseed oil fatty acids for use as a solvent. Trimethylolpropane esters were also similarly synthesized as lubricants. Finally, the discovery that lipases can also catalyze ester syntheses and transesterification reactions in organic solvent systems has opened up the possibility of enzyme catalyzed production of biodegradable polyesters. In direct polyesterification of 1,4-butanediol and sebacic acid, polyesters with a mass average molar mass of the order of 56,000 g mol-1 or higher, and a maximum molar mass of about 130,000 g mol-1 were also obtained by using lipase as biocatalyst. Finally, we have demonstrated that also aromatic polyesters can be synthesized by lipase biocatalysis, a higher than 50,000 g mol-1 mass average molar mass of poly(1,6-hexanediyl isophthalate) as an example. PMID:9866859

  20. 40 CFR 721.10190 - Formaldehyde, polymer with aliphatic diamine and phenol, reaction products with 4-methyl-2...

    Science.gov (United States)

    2010-07-01

    ... diamine and phenol, reaction products with 4-methyl-2-pentanone (generic). 721.10190 Section 721.10190... Formaldehyde, polymer with aliphatic diamine and phenol, reaction products with 4-methyl-2-pentanone (generic... identified generically as formaldehyde, polymer with aliphatic diamine and phenol, reaction products with...

  1. Investigation on the mechanism of the photoluminescence of MCM-41

    International Nuclear Information System (INIS)

    Pure siliceous MCM-41 sample was synthesized in ethylenediamine (EDA) medium. MCM-41 sample calcined at 813 K showed the most strong photoluminescent (PL) effect, while those calcined at 1073 K and 1323 K only showed weak photoluminescence. The intensity of photoluminescence decreased as the calcined temperature increased. By nuclear magnetic resonance (NMR) spectroscopy and infrared (IR) investigation, it was demonstrated that both the Al-depleted defect sites and silanol contents were responsible for the strong PL effect of the investigated MCM-41 samples. It was also suggested that the mesoporous channel structure of MCM-41 influences the investigated PL effect

  2. Photoluminescence from germanium quantum dots formed by pulsed laser deposition

    International Nuclear Information System (INIS)

    The time-resolved photoluminescence of GeOx films (x ≤ 2) containing Ge nanocrystals is carried out in the energy range of 1.4 - 3.2 eV and the relaxation time of 50 μs. The thin films are formed by the pulsed laser deposition from direct and particle flow of an erosive torch in an atmosphere of oxygen and argon. The dependence of photoluminescence properties of films on parameters of deposition and doping by gold is investigated. The results are explained in the framework of excitonic model of photoluminescence from Ge quantum dots whose sizes are determined by conditions of their formation

  3. Photoluminescent Patterned Papers Resulting from Printings of Polymeric Nanoparticles Suspension

    Directory of Open Access Journals (Sweden)

    Pierre Sarrazin

    2010-01-01

    Full Text Available The printability of a copolyfluorene-fluorenone (PFFO photoluminescent nanoparticle aqueous suspension on commercial tracing paper was here investigated. The nanoparticles suspension was obtained by miniemulsification of a suitable preformed photoluminescent organic polymer. The structural, physicochemical, and rheological characteristics of the nanoparticles suspension were first studied before considering its printability by inkjet and flexography techniques. The native properties of the nanoparticles suspension revealed to be more suitable for inkjet printing which was successfully used to print photoluminescent patterns using a very low amount of PFFO.

  4. Intimately coupling of photolysis accelerates nitrobenzene biodegradation, but sequential coupling slows biodegradation

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Lihui [Department of Environmental Science and Engineering, College of Life and Environmental Science, Shanghai Normal University, Shanghai 200234 (China); Zhang, Yongming, E-mail: zhym@shnu.edu.cn [Department of Environmental Science and Engineering, College of Life and Environmental Science, Shanghai Normal University, Shanghai 200234 (China); Bai, Qi; Yan, Ning; Xu, Hua [Department of Environmental Science and Engineering, College of Life and Environmental Science, Shanghai Normal University, Shanghai 200234 (China); Rittmann, Bruce E. [Swette Center for Environmental Biotechnology, Biodesign Institute, Arizona State University, Tempe, AZ 85287-5701 (United States)

    2015-04-28

    Highlights: • Intimately coupled UV photolysis accelerated nitrobenzene biodegradation. • NB biodegradation was slowed by accumulation of nitrophenol. • Oxalic acid was a key product of UV photolysis. • Oxalic acid accelerated biodegradation of nitrobenzene and nitrophenol by a co-substrate effect. • Intimate coupling of UV and biodegradation accentuated the benefits of oxalic acid. - Abstract: Photo(cata)lysis coupled with biodegradation is superior to photo(cata)lysis or biodegradation alone for removal of recalcitrant organic compounds. The two steps can be carried out sequentially or simultaneously via intimate coupling. We studied nitrobenzene (NB) removal and mineralization to evaluate why intimate coupling of photolysis with biodegradation was superior to sequential coupling. Employing an internal circulation baffled biofilm reactor, we compared direct biodegradation (B), biodegradation after photolysis (P + B), simultaneous photolysis and biodegradation (P&B), and biodegradation with nitrophenol (NP) and oxalic acid (OA) added individually and simultaneously (B + NP, B + OA, and B + NP + OA); NP and OA were NB’s main UV-photolysis products. Compared with B, the biodegradation rate P + B was lower by 13–29%, but intimately coupling (P&B) had a removal rate that was 10–13% higher; mineralization showed similar trends. B + OA gave results similar to P&B, B + NP gave results similar to P + B, and B + OA + NP gave results between P + B and P&B, depending on the amount of OA and NP added. The photolysis product OA accelerated NB biodegradation through a co-substrate effect, but NP was inhibitory. Although decreasing the UV photolysis time could minimize the inhibition impact of NP in P + B, P&B gave the fastest removal of NB by accentuating the co-substrate effect of OA.

  5. Wide-field time-gated photoluminescence microscopy for fast ultrahigh-sensitivity imaging of photoluminescent probes.

    Science.gov (United States)

    Razali, Wan A W; Sreenivasan, Varun K A; Bradac, Carlo; Connor, Mark; Goldys, Ewa M; Zvyagin, Andrei V

    2016-08-01

    Fluorescence microscopy is a fundamental technique for the life sciences, where biocompatible and photostable photoluminescence probes in combination with fast and sensitive imaging systems are continually transforming this field. A wide-field time-gated photoluminescence microscopy system customised for ultrasensitive imaging of unique nanoruby probes with long photoluminescence lifetime is described. The detection sensitivity derived from the long photoluminescence lifetime of the nanoruby makes it possible to discriminate signals from unwanted autofluorescence background and laser backscatter by employing a time-gated image acquisition mode. This mode enabled several-fold improvement of the photoluminescence imaging contrast of discrete nanorubies dispersed on a coverslip. It enabled recovery of the photoluminescence signal emanating from discrete nanorubies when covered by a layer of an organic fluorescent dye, which were otherwise invisible without the use of spectral filtering approaches. Time-gated imaging also facilitated high sensitivity detection of nanorubies in a biological environment of cultured cells. Finally, we monitor the binding kinetics of nanorubies to a functionalised substrate, which exemplified a real-time assay in biological fluids. 3D-pseudo colour images of nanorubies immersed in a highly fluorescent dye solution. Nanoruby photoluminescence is subdued by that of the dye in continuous excitation/imaging (left), however it can be recovered by time-gated imaging (right). At the bottom is schematic diagram of nanoruby assay in a biological fluid. PMID:27264934

  6. Swift heavy ion induced modification of aliphatic polymers

    Energy Technology Data Exchange (ETDEWEB)

    Hossain, Umme Habiba

    2015-01-15

    In this thesis, the high energy heavy ion induced modification of aliphatic polymers is studied. Two polymer groups, namely polyvinyl polymers (PVF, PVAc, PVA and PMMA) and fluoropolymers (PVDF, ETFE, PFA and FEP) were used in this work. Polyvinyl polymers were investigated since they will be used as insulating materials in the superconducting magnets of the new ion accelerators of the planned International Facility for Antiproton and Ion Research (FAIR) at the GSI Helmholtz-Centre of Heavy Ion Research (GSI) in Darmstadt. In order to study ion-beam induced degradation, all polymer foils were irradiated at the GSI linear accelerator UNILAC using several projectiles (U, Au, Sm, Xe) and experimentation sites (beam lines X0 and M3) over a large fluence regime (1 x 10{sup 10} - 5 x 10{sup 12} ions/cm{sup 2}). Five independent techniques, namely infrared (FT-IR) and ultraviolet-visible (UV-Vis) spectroscopy, residual gas analysis (RGA), thermal gravimetric analysis (TGA), and mass loss analysis (ML), were used to analyze the irradiated samples. FT-IR spectroscopy revealed that ion irradiation led to the decrease of characteristic band intensities showing the general degradation of the polymers, with scission of side groups and the main backbone. As a consequence of the structural modification, new bands appeared. UV-Vis transmission analysis showed an absorption edge shift from the ultraviolet region towards the visible region indicating double bond and conjugated double bond formation. On-line massspectrometric residual gas analysis showed the release of small gaseous fragment molecules. TGA analysis gave evidence of a changed thermal stability. With ML analysis, the considerable mass loss was quantified. The results of the five complementary analytical methods show how heavy ion irradiation changes the molecular structure of the polymers. Molecular degradation mechanisms are postulated. The amount of radiation damage is found to be sensitive to the used type of ionic

  7. Synthesis, Characterization, and Biodegradation Studies of Poly(1,4-cyclohexanedimethylene-adipate-carbonates

    Directory of Open Access Journals (Sweden)

    Ajay S. Chandure

    2014-01-01

    Full Text Available Aliphatic/alicyclic poly(1,4-cyclohexanedimethylene-adipate-carbonates (PCACs were synthesized by a transesterification from 1,4-cyclohexamethylendimethanol (1,4-CHDM, adipic acid (AA, diethyl carbonate (DEC, and titanium butoxide Ti(OBu4 as a transesterification catalyst. The synthesized PCACs were characterized by the Fourier transform infrared (FTIR, X-ray diffraction analysis (XRD, solubility, solution viscosity, gel permeation chromatography (GPC, differential scanning calorimetry (DSC, thermogravimetric analysis (TGA, and scanning electron microscope (SEM for their structural, physical, thermal, and morphological investigation. The structure of synthesized PCACs was confirmed by FTIR. All TGA curves of PCACs shows 10% weight loss above 270°C, and they reveal good thermal stability. Biodegradability of PCACs was investigated by hydrolytic degradation at (pH 7.2 and 11.5, enzymatic degradation using Rhizopus delemar lips at 37°C in phosphate buffer solution (PBS, and soil burial degradation at 30°C. The hydrolytic degradation shows the greater rate of weight loss in PBS at pH-11.5 than pH-7.2. The hydrolytic and soil burial degradation shows faster rate of weight loss as compared to enzymatic degradation. Biodegradation rate of PCACs follows the order: PCAC-20 > PCAC-40 > PCAC-60. SEM images show that degradation occurred all over the film surface, creating holes and cracks. These biodegradable PCACs may be able to replace conventional polymer in the fabrication of packaging film in near future.

  8. The prestige oil spill. I. Biodegradation of a heavy fuel oil under simulated conditions.

    Science.gov (United States)

    Díez, Sergi; Sabatté, Jordi; Viñas, Marc; Bayona, Josep M; Solanas, Anna M; Albaigés, Joan

    2005-09-01

    In vitro biodegradation of the Prestige heavy fuel oil has been carried out using two microbial consortia obtained by enrichment in different substrates to simulate its environmental fate and potential utility for bioremediation. Different conditions, such as incubation time (i.e., 20 or 40 d), oil weathering, and addition of an oleophilic fertilizer (S200), were evaluated. Weathering slowed down the degradation of the fuel oil, probably because of the loss of lower and more labile components, but the addition of S200 enhanced significantly the extension of the biodegradation. n-Alkanes, alkylcyclohexanes, alkylbenzenes, and the two- to three-ring polycyclic aromatic hydrocarbons (PAHs) were degraded in 20 or 40 d of incubation of the original oil, whereas the biodegradation efficiency decreased for higher PAHs and with the increase of alkylation. Molecular markers were degraded according to the following sequence: Acyclic isoprenoids > diasteranes > C27-steranes > betabeta-steranes > homohopanes > monoaromatic steranes > triaromatic steranes. Isomeric selectivity was observed within the C1- and C2-phenanthrenes, dibenzothiophenes, pyrenes, and chrysenes, providing source and weathering indices for the characterization of the heavy oil spill. Acyclic isoprenoids, C27-steranes, C1- and C2-naphthalenes, phenanthrenes, and dibenzothiophenes were degraded completely when S200 was used. The ratios of the C2- and C3-alkyl homologues of fluoranthene/pyrene and chrysene/benzo[a]anthracene are proposed as source ratios in moderately degraded oils. The 4-methylpyrene and 3-methylchrysene were refractory enough to serve as conserved internal markers in assessing the degradation of the aromatic fraction in a manner similar to that of hopane, as used for the aliphatic fraction.

  9. Isolation of methylene dianiline and aqueous-soluble biodegradation products from polycarbonate-polyurethanes.

    Science.gov (United States)

    Tang, Y W; Labow, R S; Santerre, J P

    2003-08-01

    Polycarbonate-polyurethanes (PCNUs) have provided the medical device industry with practical alternatives to oxidation-sensitive polyether-urethanes (PEUs). To date, many studies have focused on PCNUs synthesized with 4,4'-methylene diphenyl-diisocyanate (MDI). The relative hydrolytic stability of this class of polyurethanes is actually quite surprising given the inherent hydrolytic potential of the aliphatic carbonate group. Yet, there has been little information reporting on the rationale for the material's demonstrated hydrolytic stability. Recent work has shown that PCNU materials have a strong sensitivity towards hydrolysis when changes are made to their hard segment content and/or chemistry. However, knowledge is specifically lacking in regards of the identification of cleavage sites and the specific nature of the biodegradation products. Using high-performance liquid chromatography, radiolabel tracers and mass spectrometry, the current study provides insight into the distribution of biodegradation products from the enzyme-catalyzed hydrolysis of five different PCNUs. The hydrolytic sensitivity of the materials is shown to be related to the distribution of products, which itself is a direct consequence of unique micro-structures formed within the different materials. While an MDI-based polymer was shown to be the most hydrolytically stable material, it was the only PCNU that produced its diamine analog, in this case 4,4'-methylene dianiline (MDA), as a degradation product. Given the concern over aromatic diamine toxicity, this finding is important and highlights the fact that relative biostability is a distinct issue from that of degradation product toxicity, and that both must be considered separately when assessing the impact of biodegradation on biomaterial in vivo compatibility.

  10. Biodegradable and compostable alternatives to conventional plastics.

    Science.gov (United States)

    Song, J H; Murphy, R J; Narayan, R; Davies, G B H

    2009-07-27

    Packaging waste forms a significant part of municipal solid waste and has caused increasing environmental concerns, resulting in a strengthening of various regulations aimed at reducing the amounts generated. Among other materials, a wide range of oil-based polymers is currently used in packaging applications. These are virtually all non-biodegradable, and some are difficult to recycle or reuse due to being complex composites having varying levels of contamination. Recently, significant progress has been made in the development of biodegradable plastics, largely from renewable natural resources, to produce biodegradable materials with similar functionality to that of oil-based polymers. The expansion in these bio-based materials has several potential benefits for greenhouse gas balances and other environmental impacts over whole life cycles and in the use of renewable, rather than finite resources. It is intended that use of biodegradable materials will contribute to sustainability and reduction in the environmental impact associated with disposal of oil-based polymers. The diversity of biodegradable materials and their varying properties makes it difficult to make simple, generic assessments such as biodegradable products are all 'good' or petrochemical-based products are all 'bad'. This paper discusses the potential impacts of biodegradable packaging materials and their waste management, particularly via composting. It presents the key issues that inform judgements of the benefits these materials have in relation to conventional, petrochemical-based counterparts. Specific examples are given from new research on biodegradability in simulated 'home' composting systems. It is the view of the authors that biodegradable packaging materials are most suitable for single-use disposable applications where the post-consumer waste can be locally composted. PMID:19528060

  11. Lipase-catalyzed synthesis of oligoesters of 2,5-furandicarboxylic acid with aliphatic diols

    NARCIS (Netherlands)

    Cruz-Izquierdo, Álvaro; Broek, van den Lambertus A.M.; Serra, Juan L.; Llama, María J.; Boeriu, Carmen G.

    2015-01-01

    2,5-Furandicarboxylic acid is a platform chemical for the production of biobased polymers and materials. This study reports the synthesis of furan oligoesters via polytransesterification of dimethyl furan-2,5-dicarboxylate and linear α, ω-aliphatic diols with chain length ranging from C2 to C12,

  12. High-resolution gas chromatographic analysis of polycyclic aromatic hydrocarbons and aliphatic hydrocarbons

    International Nuclear Information System (INIS)

    A study of the analysis by gas chromatography of aromatic polycyclic hydrocarbons and aliphatic hydrocarbons is presented. The separation has been carried out by glass and fused silica capillary column in two different polar stationary phases OV-1 and SE-54. The limitation and the advantages of the procedure are discussed in terms of separation, sensitivity and precision. (Author) 20 refs

  13. IN-SITU AQUIFER RESTORATION OF CHLORINATED ALIPHATICS BY METHANOTROPHIC BACTERIA

    Science.gov (United States)

    This project evaluated the potential of enhanced in-situ biotransformation of chlorinated aliphatic solvents by a bacterial community grown on methane under aerobic conditions. The target chlorinated compounds were trichloroethene (TCE), cis-and trans-1,2-dichloroethene (DCE), an...

  14. Selection of ionic liquids for the extraction of aromatic hydrocarbons from aromatic/aliphatic mixtures

    NARCIS (Netherlands)

    Meindersma, G. Wytze; Podt, Anita (J.G.); Haan, de André B.

    2005-01-01

    The separation of aromatic hydrocarbons (benzene, toluene, ethyl benzene and xylenes) from C4 to C10 aliphatic hydrocarbon mixtures is challenging since these hydrocarbons have boiling points in a close range and several combinations form azeotropes. In this work, we investigated the separation of t

  15. PATTERN RECOGNITION ANALYSIS OF A SET OF MUTAGENIC ALIPHATIC N-NITROSAMINES

    Science.gov (United States)

    A set of 21 mutagenic aliphatic N-nitrosamines were subjected to a pattern recognition analysis using ADAPT software. Four descriptors based on molecular connectivity, geometry and sigma charge on nitrogen were capable of achieving a 100% classification using the linear learning ...

  16. Recovery of Aliphatic Hydrocarbons from Oil Field Sludge using Bacillus sp

    Directory of Open Access Journals (Sweden)

    Rizwan Ahmed Bhutto

    2015-04-01

    Full Text Available Bioremediation of aliphatic HC (Hydrocarbons in the oily sludge of Kunnar oil and gas field, Pakistan was attempted by means of previously isolated and developed Bacillus sp. Both autoclaved and non-autoclaved sludge samples were analyzed for a reaction time of 30 days with pH 7 and temperature of 380C in 50 ml MSM growth media for the sludge concentration of 5, 10 and 50% with 2, 4 and 6ml of Bacillus sp. relatively, in air atmosphere. Stabilization of the samples by microbial activity resulted in the decrease in TPH (Total Petroleum Hydrocarbon concentration by 60, 69 and 87% in autoclaved samples in contrast to the decrease of 70, 84 and 94% observed in non-autoclaved samples, relatively. Hydrocarbon degradation in oily sludge was investigated via GC which transpired that 97 and 99% concentration of aliphatic hydrocarbons in autoclaved and non-autoclaved samples was removed at 5% of TPH concentration, relatively. However, with 10% TPH concentration aliphatic hydrocarbons reduction was 68% in autoclaved samples to that of 87% in non-autoclaved samples. Further increase in the hydrocarbons concentration by 50% yielded in the removal of aliphatic hydrocarbons by 65% in autoclaved samples as compared to 98% decrease in non-autoclaved samples.

  17. STUDY ON THE PHASE TRANSITION KINETICS OF THERMOTROPIC LIQUID CRYSTALLINE AROMATIC-ALIPHATIC COPOLYESTER

    Institute of Scientific and Technical Information of China (English)

    LI Minhui; WANG Xiaogong; LIU Deshan; ZHOU Qixiang

    1991-01-01

    The phase transition kinetics of thermotropic liquid crystalline aromatic-aliphatic regular copolyester:(X) were studied by DSC. By means of Kissinger's method the kinetic equation and parameters including activation energy, rate order and preexponential factor for phase transition from nematic to isotropic were obtained. The activation energy from crystal to nematic was also presented.

  18. Phenolic and short-chained aliphatic organic acid constituents of wild oat (Avena fatua L.) seeds.

    Science.gov (United States)

    Gallagher, R S; Ananth, R; Granger, K; Bradley, B; Anderson, J V; Fuerst, E P

    2010-01-13

    The objective of this research was to identify and quantify the phenolic and short-chained aliphatic organic acids present in the seeds of three wild-type populations of wild oat and compare these results to the chemical composition of seeds from two commonly utilized wild oat isolines (M73 and SH430). Phenolic acids have been shown to serve as germination inhibitors, as well as protection for seeds from biotic and abiotic stress factors in other species, whereas aliphatic organic acids have been linked to germination traits and protection against pathogens. Wild oat populations were grown under a "common garden" environment to remove maternal variation, and the resulting seeds were extracted to remove the readily soluble and chemically bound phenolic and aliphatic organic acid components. Compounds were identified and quantified using gas chromatography-mass spectrometry. Ferulic and p-coumaric acid comprised 99% of the total phenolic acids present in the seeds, of which 91% were contained in the hulls and 98% were in the chemically bound forms. Smaller quantities of OH benzoic and vanillic acid were also detected. Soluble organic acids concentrations were higher in the M73 isoline compared to SH430, suggesting that these chemical constituents could be related to seed dormancy. Malic, succinic, fumaric and azelaic acid were the dominant aliphatic organic acids detected in all seed and chemical fractions.

  19. Enthalpy of cooperative hydrogen bonding in complexes of tertiary amines with aliphatic alcohols: Calorimetric study

    International Nuclear Information System (INIS)

    Research highlights: → Solution enthalpies of aliphatic alcohols in tertiary amines and vice versa were measured. → The enthalpies of specific interaction of amines in aliphatic alcohols are lower than the enthalpies of hydrogen bonding in 1:1 complexes amine-alcohol determined in base media. → Hydrogen bond cooperativity factors in multi-particle complexes of alcohols with aromatic amines are approximately equal for all alcohols. → Hydrogen bond cooperativity factors in multi-particle complexes of alcohols with trialkylamines decrease with increasing of alkyl radical length in alcohol and amine molecules. - Abstract: The work is devoted to the investigation of thermodynamics of specific interaction of the tertiary aliphatic and aromatic amines with associated solvents as which aliphatic alcohols were taken. Solution enthalpies of aliphatic alcohols in amines (tri-n-propylamine, 2-methylpyridine, 3-methylpyridine, N-methylimidazole) as well as amines in alcohols were measured at infinite dilution. The enthalpies of specific interaction (H-bonding) in systems studied were determined based on experimental data. The enthalpies of specific interaction of amines in aliphatic alcohols significantly lower than the enthalpies of hydrogen bonding in complexes amine-alcohol of 1:1 composition determined in base media due to the reorganization of aliphatic alcohols as solvents. The determination of solvent reorganization contribution makes possible to define the hydrogen bonding enthalpies of amines with clusters of alcohols. Obtained enthalpies of hydrogen bonding in multi-particle complexes are sensitive to the influence of cooperative effect. It was shown, that hydrogen bond cooperativity factors in multi-particle complexes of alcohols with amines are approximately equal for all alcohols when pyridines and N-methylimidazole as solutes are used. At the same time, H-bonding cooperativity factors in complexes of trialkylamines with associative species of alcohols

  20. Biodegradation of surfactant bearing wastes

    International Nuclear Information System (INIS)

    In nuclear industry, during decontamination of protective wears and contaminated materials, detergents are employed to bring down the level of radioactive contamination within safe limits. However, the surfactant present in these wastes interferes in the chemical treatment process, reducing the decontamination factor. Biodegradation is an efficient and ecologically safe method for surfactant removal. A surfactant degrading culture was isolated and inoculated separately into simulated effluents containing 1% yeast extract and 5-100 ppm sodium lauryl sulphate (SLS) and 1% yeast extract and 5-100 ppm of commercial detergent respectively. The growth of the bacterial culture and the degradation characteristics of the surfactant in the above effluents were monitored under both dynamic and static conditions. (author). 6 refs., 6 figs., 1 tab

  1. New perspectives in plastic biodegradation.

    Science.gov (United States)

    Sivan, Alex

    2011-06-01

    During the past 50 years new plastic materials, in various applications, have gradually replaced the traditional metal, wood, leather materials. Ironically, the most preferred property of plastics--durability--exerts also the major environmental threat. Recycling has practically failed to provide a safe solution for disposal of plastic waste (only 5% out of 1 trillion plastic bags, annually produced in the US alone, are being recycled). Since the most utilized plastic is polyethylene (PE; ca. 140 million tons/year), any reduction in the accumulation of PE waste alone would have a major impact on the overall reduction of the plastic waste in the environment. Since PE is considered to be practically inert, efforts were made to isolate unique microorganisms capable of utilizing synthetic polymers. Recent data showed that biodegradation of plastic waste with selected microbial strains became a viable solution. PMID:21356588

  2. Engineered biosynthesis of biodegradable polymers.

    Science.gov (United States)

    Jambunathan, Pooja; Zhang, Kechun

    2016-08-01

    Advances in science and technology have resulted in the rapid development of biobased plastics and the major drivers for this expansion are rising environmental concerns of plastic pollution and the depletion of fossil-fuels. This paper presents a broad view on the recent developments of three promising biobased plastics, polylactic acid (PLA), polyhydroxyalkanoate (PHA) and polybutylene succinate (PBS), well known for their biodegradability. The article discusses the natural and recombinant host organisms used for fermentative production of monomers, alternative carbon feedstocks that have been used to lower production cost, different metabolic engineering strategies used to improve product titers, various fermentation technologies employed to increase productivities and finally, the different downstream processes used for recovery and purification of the monomers and polymers.

  3. Engineered biosynthesis of biodegradable polymers.

    Science.gov (United States)

    Jambunathan, Pooja; Zhang, Kechun

    2016-08-01

    Advances in science and technology have resulted in the rapid development of biobased plastics and the major drivers for this expansion are rising environmental concerns of plastic pollution and the depletion of fossil-fuels. This paper presents a broad view on the recent developments of three promising biobased plastics, polylactic acid (PLA), polyhydroxyalkanoate (PHA) and polybutylene succinate (PBS), well known for their biodegradability. The article discusses the natural and recombinant host organisms used for fermentative production of monomers, alternative carbon feedstocks that have been used to lower production cost, different metabolic engineering strategies used to improve product titers, various fermentation technologies employed to increase productivities and finally, the different downstream processes used for recovery and purification of the monomers and polymers. PMID:27260524

  4. Biodegradable Metals From Concept to Applications

    CERN Document Server

    Hermawan, Hendra

    2012-01-01

    This book in the emerging research field of biomaterials covers biodegradable metals for biomedical applications. The book contains two main parts where each of them consists of three chapters. The first part introduces the readers to the field of metallic biomaterials, exposes the state of the art of biodegradable metals, and reveals its application for cardiovascular implants. It includes some fundamental aspects to give basic understanding on metals for further review on the degradable ones is covered in chapter one. The second chapter introduces the concept of biodegradable metals, it's st

  5. Photoluminescence and Raman Spectroscopy Studies of Carbon Nitride Films

    OpenAIRE

    Hernández-Torres, J.; Gutierrez-Franco, A.; P. G. González; L. García-González; Hernandez-Quiroz, T.; Zamora-Peredo, L.; V.H. Méndez-García; A. Cisneros-de la Rosa

    2016-01-01

    Amorphous carbon nitride films with N/C ratios ranging from 2.24 to 3.26 were deposited by reactive sputtering at room temperature on corning glass, silicon, and quartz as substrates. The average chemical composition of the films was obtained from the semiquantitative energy dispersive spectroscopy analysis. Photoluminescence measurements were performed to determine the optical band gap of the films. The photoluminescence spectra displayed two peaks: one associated with the substrate and the ...

  6. Enhancement of carbon nanotube photoluminescence by photonic crystal nanocavities

    OpenAIRE

    Watahiki, R.; Shimada, T; Zhao, P; Chiashi, S.; Iwamoto, S.; Arakawa, Y; Maruyama, S.; Kato, Y. K.

    2012-01-01

    Photonic crystal nanocavities are used to enhance photoluminescence from single-walled carbon nanotubes. Micelle-encapsulated nanotubes are deposited on nanocavities within Si photonic crystal slabs and confocal microscopy is used to characterize the devices.Photoluminescencespectra and images reveal nanotube emission coupled to nanocavity modes. The cavity modes can be tuned throughout the emission wavelengths of carbon nanotubes, demonstrating the ability to enhance photoluminescence from a...

  7. Observation of nitrogen vacancy photoluminescence from an optically levitated nanodiamond

    OpenAIRE

    Neukirch, Levi P.; Gieseler, Jan; Quidant, Romain; Novotny, Lukas; Nick Vamivakas, A.

    2013-01-01

    We present the first evidence of nitrogen vacancy (NV) photoluminescence from a nanodiamond suspended in a free-space optical dipole trap at atmospheric pressure. The photoluminescence rates are shown to decrease with increasing trap laser power, but are inconsistent with a thermal quenching process. For a continuous-wave trap, the neutral charge state (NV$^0$) appears to be suppressed. Chopping the trap laser yields higher total count rates and results in a mixture of both NV$^0$ and the neg...

  8. Photoluminescent carbogenic nanoparticles directly derived from crude biomass

    KAUST Repository

    Krysmann, Marta J.

    2012-01-01

    We present an environmentally benign, energy efficient and readily scalable approach to synthesize photoluminescent carbogenic nanoparticles directly from soft tissue biomass. Our approach relies on the pyrolytic decomposition of grass that gives rise to the formation of well-defined nanoparticles. The carbogenic nanoparticles can be readily surface modified, generating a series of highly selective photoluminescent materials that exhibit remarkable stability upon prolonged exposure to aggressive, high-temperature, high-salinity environment. © 2012 The Royal Society of Chemistry.

  9. Preparation and degradation mechanisms of biodegradable polymer: a review

    Science.gov (United States)

    Zeng, S. H.; Duan, P. P.; Shen, M. X.; Xue, Y. J.; Wang, Z. Y.

    2016-07-01

    Polymers are difficult to degrade completely in Nature, and their catabolites may pollute the environment. In recent years, biodegradable polymers have become the hot topic in people's daily life with increasing interest, and a controllable polymer biodegradation is one of the most important directions for future polymer science. This article presents the main preparation methods for biodegradable polymers and discusses their degradation mechanisms, the biodegradable factors, recent researches and their applications. The future researches of biodegradable polymers are also put forward.

  10. Using quantum dot photoluminescence for load detection

    Science.gov (United States)

    Moebius, M.; Martin, J.; Hartwig, M.; Baumann, R. R.; Otto, T.; Gessner, T.

    2016-08-01

    We propose a novel concept for an integrable and flexible sensor capable to visualize mechanical impacts on lightweight structures by quenching the photoluminescence (PL) of CdSe quantum dots. Considering the requirements such as visibility, storage time and high optical contrast of PL quenching with low power consumption, we have investigated a symmetrical and an asymmetrical layer stack consisting of semiconductor organic N,N,N',N'-Tetrakis(3-methylphenyl)-3,3'-dimethylbenzidine (HMTPD) and CdSe quantum dots with elongated CdS shell. Time-resolved series of PL spectra from layer stacks with applied voltages of different polarity and simultaneous observation of power consumption have shown that a variety of mechanisms such as photo-induced charge separation and charge injection, cause PL quenching. However, mechanisms such as screening of external field as well as Auger-assisted charge ejection is working contrary to that. Investigations regarding the influence of illumination revealed that the positive biased asymmetrical layer stack is the preferred sensor configuration, due to a charge carrier injection at voltages of 10 V without the need of coincident illumination.

  11. Photoluminescence of carbon dots from mesoporous silica

    Science.gov (United States)

    Nelson, D. K.; Razbirin, B. S.; Starukhin, A. N.; Eurov, D. A.; Kurdyukov, D. A.; Stovpiaga, E. Yu; Golubev, V. G.

    2016-09-01

    Photophysical properties of carbon dots were investigated under various excitation conditions and over a wide temperature region - from room to liquid helium temperatures. The carbon dots (CDs) were synthesized using mesoporous silica particles as a reactor and (3-aminopropyl)triethoxysilane (APTES) as a precursor. The photoluminescence spectra of CDs exhibit a strong dependence on the excitation wavelength and demonstrate a significant inhomogeneous broadening. Lowering sample temperature reveals the doublet structure of the spectra, which is associated with the vibronic structure of radiative transitions. The vibration energy ∼1200 cm-1 is close to the energy of Csbnd O stretching vibration. Long-lived phosphorescence of carbon dots with its decay time ∼0.2 s at T = 80 K was observed. The fluorescence and phosphorescence spectra are shown to be spectrally separated. The long-lived component of the emission was ascribed to optically forbidden triplet-singlet transitions. The value of the singlet-triplet splitting was found to be about 0.3 eV. Photo-induced polarization of the luminescence of carbon dots was revealed. The degree of the linear polarization is dependent on the wavelengths of both excitation and emitted light. The effect indicates a hidden anisotropy of optical dipole transitions in the dots and demonstrates the loss of the dipole orientation during the electron energy relaxation.

  12. Photoluminescence of P3HT nanoparticles

    Science.gov (United States)

    Dujovne, Irene; Labastide, Joelle; Baghgar, Mina; McKenna, Aidan; Barnes, Austin M.; Venkataraman, D.; Barnes, Michael D.

    2012-02-01

    Polythiophenes are semiconducting polymers that have been designed to crystallize. The photophysics of semicrystalline polythiophene and polythiophene-blends are the focus of intense research efforts across different disciplines. In these systems there is a competition between charge separation and recombination. Exciton diffusion length in organic-semiconductors is a major road-block for efficient solar energy harvesting devices since, for direct bandgap organic materials, this distance is about 10 nanometers. Thus, efficient extraction of photogenerated electrons and holes requires engineering polymer domain dimensions in this size range. In our initial investigations of the photophysics of isolated P3HT nanoparticles (15 - 130 nm), we have observed several intriguing size-dependent features in the single-particle photoluminescence (PL) connected with exciton diffusion and dissociation dynamics. In addition to the short-time behavior, we also observe size-dependent differences in PL decay at long times. In the 10 - 100 ns time regime, the PL originates not from radiative transitions of bound excitons, but rather from charge-separation followed by bi-polaron recombination--and thus provides an interesting measure of exciton fission probability within the nanoparticle.

  13. Photoluminescent Detection of Dissolved Underwater Trace Explosives

    Directory of Open Access Journals (Sweden)

    Tye Langston

    2010-01-01

    Full Text Available A portable, rapid, and economical method for in situ trace explosive detection in aqueous solutions was demonstrated using photoluminescence. Using europium/thenoyltrifluoroacetone as the reagent, dissolved nitroglycerin was fluorescently tagged and detected in seawater solutions without sample preparation, drying, or preconcentration. The chemical method was developed in a laboratory setting and demonstrated in a flow-through configuration using lightweight, inexpensive, commercial components by directly injecting the reagents into a continually flowing seawater stream using a small amount of organic solvent (approximately 8% of the total solution. Europium's vulnerability to vibrational fluorescence quenching by water provided the mode of detection. Without nitroglycerin in the seawater solution, the reagent's fluorescence was quenched, but when dissolved nitroglycerin was present, it displaced the water molecules from the europium/thenoyltrifluoroacetone compound and restored fluorescence. This effort focused on developing a seawater sensor, but performance comparisons were made to freshwater. The method was found to perform better in freshwater and it was shown that certain seawater constituents (such as calcium have an adverse impact. However, the concentrations of these constituents are not expected to vary significantly from the natural seawater used herein.

  14. Plasmonic enhancement of photoluminescence from aluminium nitride

    Science.gov (United States)

    Flynn, Chris; Stewart, Matthew

    2016-03-01

    Aluminium nitride (AlN) films were grown on c-plane sapphire wafers by molecular beam epitaxy (MBE) under aluminium-rich conditions. The excess aluminium (Al) accumulated on the surface of the films as micro-scale droplets 1-10 μm in size, and as Al nanoparticles with diameters in the range 10-110 nm. Photoluminescence (PL) measurements were performed on the AlN samples using a 193 nm Excimer laser as the excitation source. Prior to PL measurements the wafers were cleaved in half. One half of each wafer was submitted to a 10 min treatment in H3PO4 heated to 70 °C to remove the excess Al from the film surface. The remaining half was left in the as-deposited condition. The mean intensities of the near-band-edge PL peaks of the as-deposited samples were 2.0-3.4 times higher compared to the samples subjected to the H3PO4 Al-removal treatment. This observation motivated calculations to determine the optimal Al surface nanosphere size for plasmonic enhancement of PL from AlN. The PL enhancement was found to peak for an Al nanosphere radius of 15 nm, which is within the range of the experimentally-observed Al nanoparticle sizes.

  15. Preparation of photoluminescent carbon dots-embedded polyelectrolyte microcapsules

    Institute of Scientific and Technical Information of China (English)

    Xiaoling Yang; Liming Peng; Jie Zong; Yihua Zhu

    2013-01-01

    Two types of photoluminescent carbon dots (CDs)-embedded polyelectrolyte (PE) microcapsules were successfully prepared via the layer-by-layer (LbL) assembly approach on sacrificial templates.For the first type,the PE microcapsules with CDs embedded in the cavity were produced from assembly of five pairs of poly(sodium 4-styrensulfonate) (PSS) and poly(allylamine hydrochloride) (PAH) on CDs-pre-loaded meso-porous silica.For the second type,the PE microcapsules with CDs embedded in the wall were made of CDs and PAH,which were derived from SiO2 particles as templates.Microscope images confirmed the introduction of CDs into the two CDs-embedded microcapsules.These two microcapsules also retained the optical properties of free CDs.Photoluminescence spectra revealed that the two types of microcapsules had excitation-dependent photoluminescence behavior.When the excitation wavelength changed from 280 to 340 nm,photoluminescence emission peak of the PE microcapsules with CDs embedded in the cavity shifts from 369 to 377 nm,while for microcapsules with CDs embedded in the wall,emission peak shifts from 367 to 390 nm.Due to low toxicity,good hydrophilicity and photoluminescence properties of CDs,these two kinds of photo-luminescent microcapsules have competitive potential for application in carriers for imaging,drug delivery and biosensors.

  16. Biodegradable polymers: Which, when and why?

    Directory of Open Access Journals (Sweden)

    Kotwal V

    2007-01-01

    Full Text Available The plethora of drug therapies and types of drugs demand different formulations, fabrications conditions and release kinetics. No single polymer can satisfy all the requirements. Therefore there have been tremendous advances in area of biodegradable copolymers over the last 30 years. This article reviews current research on biodegradable polymers, focusing their potential as drug carries. The major classes of polymers are briefly discussed with regard to synthesis, properties and biodegradability, and known degradation modes and products are indicated based on studies reported in the literature. A vast majority of biodegradable polymers studied belongs to the polyester family, which includes polyglycolides and polylactides. Other degradable polymers such as polyorthoesters, polyanhydrides and polyphosphazenes are also discussed and their advantages and disadvantages are summarized.

  17. Phyllosphere yeasts rapidly break down biodegradable plastics

    OpenAIRE

    Kitamoto, Hiroko K.; Shinozaki, Yukiko; Cao, Xiao-hong; Morita, Tomotake; Konishi, Masaaki; Tago, Kanako; Kajiwara, Hideyuki; Koitabashi, Motoo; Yoshida, Shigenobu; Watanabe, Takashi; Sameshima-Yamashita, Yuka; Nakajima-Kambe, Toshiaki; Tsushima, Seiya

    2011-01-01

    The use of biodegradable plastics can reduce the accumulation of environmentally persistent plastic wastes. The rate of degradation of biodegradable plastics depends on environmental conditions and is highly variable. Techniques for achieving more consistent degradation are needed. However, only a few microorganisms involved in the degradation process have been isolated so far from the environment. Here, we show that Pseudozyma spp. yeasts, which are common in the phyllosphere and are easily ...

  18. Biodegradation and toxicological evaluation of lubricant oils

    OpenAIRE

    Ivo Shodji Tamada; Paulo Renato Matos Lopes; Renato Nallin Montagnolli; Ederio Dino Bidoia

    2012-01-01

    The aim of this work was to compare different toxicity levels of lubricant oils. The tests were performed using the earthworm (Eisenia andrei), arugula seeds (Eruca sativa) and lettuce seeds (Lactuca sativa), with three types of contaminants (mineral lubricant oil, synthetic lubricant oil and used lubricant oil) for various biodegradation periods in the soil. The toxicity tests indirectly measured the biodegradation of the contaminants. The samples were analyzed at t0, t60, t120 and t180 days...

  19. Biodegradation of cresol isomers in anoxic aquifers.

    OpenAIRE

    Smolenski, W J; Suflita, J M

    1987-01-01

    The biodegradation of o-, m-, and p-cresol was examined in material obtained from a shallow anaerobic alluvial sand aquifer. The cresol isomers were preferentially metabolized, with p-cresol being the most easily degraded. m-Cresol was more persistent than the para-isomer, and o-cresol persisted for over 90 days. Biodegradation of cresol isomers was favored under sulfate-reducing conditions (SRC) compared with that under methanogenic conditions (MC). Slurries that were acclimated to p-cresol ...

  20. Lubricant Biodegradation Enhancers:Designed Chemistry and Engineered Technology

    Institute of Scientific and Technical Information of China (English)

    Chen Boshui; Gao Lingyue; Fang Jianhua; Zhang Nan; Wu Jiang; Wang Jiu

    2015-01-01

    In recent decades, a growing worldwide trend of developing the biodegradable lubricants has been prevailing to form a speciifc ifeld of green chemistry and green engineering. Enhancement of biodegradability of unreadily biodegradable petroleum-based lubricants has as such become an urgent must. For over a decade the authors have been focusing on the im-provement of biodegradability of unreadily biodegradable lubricants such as petroleum-based lubricating oils and greases. A new idea of lubricant biodegradation enhancer was put forward by the authors with the aim to stimulate the biodegradation of unreadily biodegradable lubricants by incorporating the enhancer into the lubricants in order to turn the lubricants into greener biodegradable ones and to help in situ bioremediation of lubricant-contaminated environment. This manuscript sum-marizes our recent efforts relating to the chemistry and technology of biodegradation enhancers for lubricants. Firstly, the chemistry of lubricant biodegradation enhancers was designed based on the principles of bioremediation for the treatment of hydrocarbon contaminated environment. Secondly, the ability of the designed biodegradation enhancers for increasing the biodegradability of unreadily biodegradable industrial lubricants was investigated through biodegradability evaluation tests, microbial population analysis, and biodegradation kinetics modeling. Finally, the impact of biodegradation enhancers on some crucial performance characteristics of lubricants such as lubricity and oxidation stability was tested via tribological evaluation and oxidation determinations. Our results have shown that the designed chemistry of nitrogenous and/or phos-phorous compounds such as lauroyl glutamine, oleoyl glycine, oleic diethanolamide phosphate and lauric diethanolamide borate was outstanding in boosting biodegradation of petroleum-based lubricants which was ascribed to increase the micro-bial population and decrease the oil-water interfacial

  1. Biodegradability of Chlorinated Anilines in Waters

    Institute of Scientific and Technical Information of China (English)

    CHAO WANG; GUAN-GHUA LU; YAN-JIE ZHOU

    2007-01-01

    Objective To identify the bacteria tolerating chlorinated anilines and to study the biodegradability of o-chloroaniline and its coexistent compounds. Methods Microbial community of complex bacteria was identified by plate culture observation techniques and Gram stain method. Bacterial growth inhibition test was used to determine the tolerance of complex bacteria to toxicant. Biodegradability of chlorinated anilines was determined using domesticated complex bacteria as an inoculum by shaking-flask test. Results The complex bacteria were identified, consisting of Xanthomonas, Bacillus alcaligenes,Acinetobacter, Pseudomonas, and Actinomycetaceae nocardia. The obtained complex bacteria were more tolerant to o-chloroaniline than mixture bacteria in natural river waters. The effects of exposure concentration and inoculum size on the biodegradability of o-chloroaniline were analyzed, and the biodegradation characteristics of single o-chloroaniline and 2,4-dichloroaniline were compared with the coexistent compounds. Conclusion The biodegradation rates can be improved by decreasing concentration of compounds and increasing inoculum size of complex bacteria. When o-chloroaniline coexists with aniline, the latter is biodegraded prior to the former, and as a consequence the metabolic efficiency of o-chloroaniline is improved with the increase of aniline concentration. Meanwhile, when o-chloroaniline coexists with 2,4-dichloroaniline, the metabolic efficiency of 2,4-dichloroaniline is markedly improved.

  2. Tuning different kinds of entangled metal-organic frameworks by modifying the spacer group of aliphatic dicarboxylate ligands and the reactant ratio.

    Science.gov (United States)

    Yang, Jin-Xia; Zhai, Ji-Quan; Zhang, Xin; Qin, Ye-Yan; Yao, Yuan-Gen

    2016-01-14

    Taking advantage of the conformational flexibility of the bpp ligand and aliphatic dicarboxylic acids, six interesting entangled coordination polymers, {[Cd(fum)(bpp)(H2O)]·(H2O)}n (), {[Cd(fum)(bpp)2]·(H2O)5}n (), {[Cd2(suc)1.5(bpp)2(NO3)(H2O)2]·6H2O}n (), {[Cd(suc)(bpp)2]·(H2O)1.5}n (), {[Cd2(glu)2(bpp)3]·10H2O}n (), and {Cd(adp)(bpp)(H2O)}n () have been prepared and structurally characterized (bpp = 1,3-bi(4-pyridyl)propane, fum = fumaric, suc = succinate, glu = glutaric, adp = adipic). Compounds and are comprised of undulated 2D 4(4)-sql networks. In the structure of compound , two identical undulated layers are parallelly interpenetrated with each other to give a 2D → 2D interpenetrating framework. For , the dangling arms projected from 2D layers are intercalated into the neighboring sheets, producing a 2D → 3D polythreading framework. Compound shows a rare example of a 2D self-penetrating framework with a (3,4)-connected (4(2)·6(3)·8)(4(2)·6) topology. Compound presents an unusual 2D self-threading network with a novel 4-connected {4(2)·6(3)·8} topology. Compound displays a 3D self-penetrating system based on a 2D → 3D parallel polycatenation array. Compound exhibits an unprecedented 3D self-penetrating structure having both 1D + 1D → 1D polycatenation and 3D + 3D → 3D interpenetration characteristics. A comparison of these six compounds demonstrates that both the different spacer lengths of the aliphatic dicarboxylates and reactant ratios appear to play a significant role in the assembly of entangled frameworks. In addition, thermal stabilities and photoluminescence properties of have been examined in the solid state at room temperature. PMID:26621568

  3. Self-assembly of short peptides composed of only aliphatic amino acids and a combination of aromatic and aliphatic amino acids.

    Science.gov (United States)

    Subbalakshmi, Chilukuri; Manorama, Sunkara V; Nagaraj, Ramakrishnan

    2012-05-01

    The morphology of structures formed by the self-assembly of short N-terminal t-butyloxycarbonyl (Boc) and C-terminal methyl ester (OMe) protected and Boc-deprotected hydrophobic peptide esters was investigated. We have observed that Boc-protected peptide esters composed of either only aliphatic hydrophobic amino acids or aliphatic hydrophobic amino acids in combination with aromatic amino acids, formed highly organized structures, when dried from methanol solutions. Transmission and scanning electron microscopic images of the peptides Boc-Ile-Ile-OMe, Boc-Phe-Phe-Phe-Ile-Ile-OMe and Boc-Trp-Ile-Ile-OMe showed nanotubular structures. Removal of the Boc group resulted in disruption of the ability to form tubular structures though spherical aggregates were formed. Both Boc-Leu-Ile-Ile-OMe and H-Leu-Ile-Ile-OMe formed only spherical nanostructures. Dynamic light scattering studies showed that aggregates of varying dimensions were present in solution suggesting that self-assembly into ordered structures is facilitated by aggregation in solution. Fourier transform infrared spectroscopy and circular dichroism spectroscopy data show that although all four of the protected peptides adopt well-defined tertiary structures, upon removal of the Boc group, only H-Phe-Phe-Phe-Ile-Ile-OMe had the ability to adopt β-structure. Our results indicate that hydrophobic interaction is a very important determinant for self-assembly and presence of charged and aromatic amino acids in a peptide is not necessary for self-assembly. PMID:22431418

  4. Study on the Antimicrobial Properties of Citrate-Based Biodegradable Polymers

    Directory of Open Access Journals (Sweden)

    Lee-Chun eSu

    2014-07-01

    Full Text Available Citrate-based polymers possess unique advantages for various biomedical applications since citric acid is a natural metabolism product, which is biocompatible and antimicrobial. In polymer synthesis, citric acid also provides multiple functional groups to control the crosslinking of polymers and active binding sites for further conjugation of biomolecules. Our group recently developed a number of citrate-based polymers for various biomedical applications by taking advantage of their controllable chemical, mechanical, and biological characteristics. In this study, various citric acid derived biodegradable polymers were synthesized and investigated for their physicochemical and antimicrobial properties. Results indicate that citric acid derived polymers reduced bacterial proliferation to different degrees based on their chemical composition. Among the studied polymers, poly(octamethylene citrate (POC showed approximately 70-80% suppression to microbe proliferation, owing to its relatively higher ratio of citric acid contents. Crosslinked urethane-doped polyester elastomers (CUPEs and biodegradable photoluminescent polymers (BPLPs also exhibited significant bacteria reduction of ~20% and ~50% for Staphylococcus aureus and Escherichia coli, respectively. Thus, the intrinsic antibacterial properties in citrate-based polymers enable them to inhibit bacteria growth without incorporation of antibiotics, silver nanoparticles, and other traditional bacteria-killing agents suggesting that they are unique beneficial materials for wound dressing, tissue engineering, and other potential medical applications where antimicrobial property is desired.

  5. A study of aliphatic amino acids using simulated vibrational circular dichroism and Raman optical activity spectra

    CERN Document Server

    Ganesan, Aravindhan; Wang, Feng

    2013-01-01

    Vibrational optical activity (VOA) spectra, such as vibrational circular dichroism (VCD) and Raman optical activity (ROA) spectra, of aliphatic amino acids are simulated using density functional theory (DFT) methods in both gas phase (neutral form) and solution (zwitterionic form), together with their respective infrared (IR) and Raman spectra of the amino acids. The DFT models, which are validated by excellent agreements with the available experimental Raman and ROA spectra of alanine in solution, are employed to study other aliphatic amino acids. The inferred (IR) intensive region (below 2000 cm-1) reveals the signature of alkyl side chains, whereas the Raman intensive region (above 3000 cm-1) contains the information of the functional groups in the amino acids. Furthermore, the chiral carbons of the amino acids (except for glycine) dominate the VCD and ROA spectra in the gas phase, but the methyl group vibrations produce stronger VCD and ROA signals in solution. The C-H related asymmetric vibrations domina...

  6. Aliphatic C-H---Anion Hydrogen Bonds: Weak Contacts or Strong Interactions?

    Energy Technology Data Exchange (ETDEWEB)

    Hay, Benjamin [ORNL; Pedzisa, Lee [ORNL

    2009-01-01

    Electronic structure calculations, MP2/aug-cc-pVDZ, are used to determine C H---Cl hydrogen bond energies for a series of XCH3 donor groups in which the electron-withdrawing ability of X is varied over a wide range of values. When attached to polarizing substituents, aliphatic CH groups are moderate to strong hydrogen bond donors, exhibiting interaction energies comparable to those obtained with O H and N H groups. The results explain why aliphatic C H donors are observed to function as competitive binding sites in solution and suggest that such C H---anion contacts should be considered as possible contributors when evaluating the denticity of an anion receptor.

  7. Determination of aliphatic organic acids by high-performance liquid chromatography with pulsed electrochemical detection.

    Science.gov (United States)

    Casella, Innocenzo G; Gatta, Maria

    2002-01-01

    A new ion exclusion HPLC procedure accomplished with a pulsed electrochemical detection for the determination of several common aliphatic acids is described. A triple-step waveform of the applied potentials, based on the formation/inhibition of PtOH species on the electrode surface, is successfully used for sensitive detection of several aliphatic acids in flowing systems avoiding pre- or postcolumn derivatization and/or cleanup procedures. Under optimal chromatographic conditions (i.e., 50 mM HClO(4)) the proposed method allowed detection limits between 0.5 and 7 microM for all investigated acids, and the dynamic linear range spanned generally over 1 or 2 orders of magnitude. Determination of citric, malic, tartaric, lactic, formic, and acetic acids in several foods and beverages was performed, in approximately 15 min, without the necessity of any sample pretreatment. PMID:11754537

  8. Study on Aromatization of C6 Aliphatic Hydrocarbons on ZRP Zeolite Catalyst

    Institute of Scientific and Technical Information of China (English)

    Wang Yongjun; Xie Chaogang

    2004-01-01

    The performance of ZRP zeolite catalysts for aromatization of C6 aliphatic hydrocarbons was investigated in a pulsed microreactor. The influence of metal modified ZRP zeolites on aromatization reaction was also studied, coupled with comparison of aromatization tendencies of olefins, paraffins and paraffins with different degrees of chain branching. Test results had shown that the lower the silicon/aluminum ratio in the ZRP zeolite, the higher the aromatization reactivity of aliphatic hydrocarbons. Modification of ZRP zeolite by zinc and its zinc content had apparent impact on the yield and distribution of aromatics. The aromatization tendency of olefins was apparently better than paraffins, while the aromatization tendency of monomethyl paraffins was better than that of straight-chain paraffins with the exception of dimethyl paraffins, which had worse aromatization tendency because of their steric hindrance.

  9. Development and Characterization of Novel Interpenetrating Network (IPN) Foams from Epoxy Ester and Aliphatic Epoxy Resin

    OpenAIRE

    Patel, Kanuprasad; Desai, Dhirubhai; Bhuva, Santosh

    2009-01-01

    Diglycidyl ether of bisphenol-A (DGEBA) was reacted with acrylate monomer at variable molar ratios. The reaction between glycerine and epichlorohydrine form glycidyl ether of polyol aliphatic epoxy resin. The resultant resins were characterized duly. Both the resins were mixed at different ratios with constant high shear stirring. The obtained mixture and suitable additives were heated at 150oC for one and half hour. The so called Interpenetrating Network (IPN) transformed into foams. The per...

  10. Hydrogenation of Aliphatic Alkenes in a High-Temperature High-Pressure Packed-Bed Microreactor

    OpenAIRE

    Stavárek, Petr

    2012-01-01

    This contribution presents results of the characterization of a new high-temperature high-pressure integrated packed-bed microreactor (MCTU 600 from Ehrfeld Mikrotechnik BTS GmbH) for lab-scale catalyst testing. As the model reaction we used the hydrogenation of C4-C5 aliphatic alkenes heterogeneously catalyzed by Pt/Al2O3 or Pd/Al2O3.

  11. Pattern recognition analysis of a set of mutagenic aliphatic N-nitrosamines.

    OpenAIRE

    Nesnow, S; Langenbach, R; Mass, M J

    1985-01-01

    A set of 21 mutagenic aliphatic N-nitrosamines were subjected to a pattern recognition analysis using ADAPT software. Four descriptors based on molecular connectivity, geometry and sigma charge on nitrogen were capable of achieving a 100% classification using the linear learning machine or iterative least squares algorithms. Three descriptors were capable of a 90.5% and two descriptors of a 85.7% overall correct classification. Three of the four descriptors were each capable of classifying 15...

  12. Production of aliphatic carboxylic acids during the alkali catalysed decomposition of cellulose

    OpenAIRE

    Efhil, Mohamed

    2013-01-01

    The degradation of cellulosic materials under alkaline condition (sodium hydroxide) using High performance ion exclusion chromatography (HPIEC) Dionex ICS‐3000 to analyse the samples at different temperatures (at room, at 50 °C, at 90 °C), under atmosphere of N2 during 188 hours, by using acrylic acid as internal standard, resulted in complex mixture of compounds, including isosaccharinic acid. The retention time of aliphatic organic acids measured under the conditions outlined i...

  13. A QSPR STUDY OF NORMAL BOILING POINT OF ORGANIC COMPOUNDS (ALIPHATIC ALKANES) USING MOLECULAR DESCRIPTORS

    OpenAIRE

    B. Souyei; M. Korichi

    2013-01-01

    A quantitative structure–property relationship (QSPR) study is carried out to develop correlations that relate the molecular structures of organic compounds (Aliphatic Alkanes) to their normal boiling point (NBP) and two correlations were proposed for constitutionals and connectivity indices Models. The correlations are simple in application with good accuracy, which provide an easy, direct and relatively accurate way to calculate NBP. Such calculation gives us a model that gives results in r...

  14. Synthesis and reactivity of aliphatic sulfur pentafluorides from substituted (pentafluorosulfanyl)benzenes

    OpenAIRE

    Vida, Norbert; Václavík, Jiří; Beier, Petr

    2016-01-01

    Oxidation of 3- and 4-pentafluorosulfanyl-substituted anisoles and phenols with hydrogen peroxide and sulfuric acid provided a mixture of SF5-substituted muconolactone, maleic, and succinic acids. A plausible mechanism for the formation of the aliphatic SF5 compounds was presented and their chemical reactivity was investigated. SF5-substituted para-benzoquinone was synthesized; its oxidation led to an improved yield of 2-(pentafluorosulfanyl)maleic acid. The reaction of SF5-substituted maleic...

  15. Modification of nano-sized layered double hydroxides by long-chain organic aliphatic surfactants

    OpenAIRE

    RAMASAMY ANBARASAN; SEUNG SOON IM; WANDUC LEE

    2008-01-01

    The inter-layer anion of layered double hydroxides (LDH) with a hydrotalcite (HT)-like structure was ion-exchanged with various organic surfactants, particularly with long chain aliphatic surfactants. After the ion-exchange process, the basal spacing of the LDH was increased and the increase of the basal spacing depended on various factors, such as the intercalation capacity functionality and orientation capability of the surfactant. Of the employed surfactants, stearic acid intercalated LDH ...

  16. Computation of Bond Dissociation Energies for Removal of Nitrogen Dioxide Groups in Certain Aliphatic Nitro Compounds

    Institute of Scientific and Technical Information of China (English)

    SHAO Ju-Xiang; CHENG Xin-Lu; YANG Xiang-Dong; XIANG Shi-Kai

    2006-01-01

    @@ Bond dissociation energies for removal of nitrogen dioxide groups in 10 aliphatic nitro compounds, including nitromethane, nitroethylene, nitroethane, dinitromethane, 1-nitropropane, 2-nitropropane, 1-nitrobutane,2-methyl-2-nitropropane, nitropentane, and nitrohexane, are calculated using the highly accurate complete basis set (CBS-Q) and the three hybrid density functional theory (DFT) methods B3LYP, B3PW91 and B3P86 with 6-31G** basis set.

  17. Secondary organic aerosol formation from primary aliphatic amines with NO3 radical

    OpenAIRE

    Q. G. J. Malloy; Li Qi; B. Warren; Cocker III, D. R.; M. E. Erupe; Silva, P J

    2009-01-01

    Primary aliphatic amines are an important class of nitrogen containing compounds emitted from automobiles, waste treatment facilities and agricultural animal operations. A series of experiments conducted at the UC-Riverside/CE-CERT Environmental Chamber is presented in which oxidation of methylamine, ethylamine, propylamine, and butylamine with O3 and NO3 have been investigated. Very little aerosol formation is observed in the presence of O3 only. However, after addition of ...

  18. Secondary organic aerosol formation from primary aliphatic amines with NO3 radical

    OpenAIRE

    M. E. Erupe; Cocker III, D. R.; B. Warren; Li Qi; Q. G. J. Malloy; Silva, P J

    2008-01-01

    Primary aliphatic amines are an important class of nitrogen containing compounds found to be emitted from automobiles, waste treatment facilities and agricultural animal operations. A series of experiments conducted at the UC-Riverside/CE-CERT Environmental Chamber is presented in which oxidation of methylamine, ethylamine, propylamine, and butylamine with NO3 has been investigated. Very little aerosol formation is observed in the presence of O3 only. However, after addition of NO, and by ext...

  19. Secondary Organic Aerosol Formation from Primary Aliphatic Amines with Nitrate Radical

    OpenAIRE

    Q. G. J. Malloy; Qi, L; B. Warren; Cocker III, D. R.; M. E. Erupe; Silva, P J

    2009-01-01

    Primary aliphatic amines are an important class of nitrogen containing compounds emitted from automobiles, waste treatment facilities and agricultural animal operations. A series of experiments conducted at the UC-Riverside/CECERT Environmental Chamber is presented in which oxidation of methylamine, ethylamine, propylamine, and butylamine with O3 and NO3 have been investigated. Very little aerosol formation is observed in the presence of O3 only. However, after addition of NO, and by extensio...

  20. Coefficients of caffeine distribution in aliphatic alcohol-ammonium sulfate-water systems

    Science.gov (United States)

    Korenman, Ya. I.; Krivosheeva, O. A.; Mokshina, N. Ya.

    2012-11-01

    The extraction of caffeine with aliphatic alcohols C3-C9 from aqueous solutions in the presence of a salting-out agent (ammonium sulfate) is studied. Quantitative characteristics of extraction are calculated: the distribution coefficients ( D) and the degree of recovery ( R, %). Relations are found between log D of caffeine and the length of the hydrocarbon radical in the alcohol molecule, along with certain physicochemical properties of the extragents.

  1. Biodegradation Of Polycyclic Aromatic Hydrocarbons In Petroleum Oil Contaminating The Environment

    International Nuclear Information System (INIS)

    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous pollutants in urban atmospheres (Chen et al., 2013). PAHs enter the environment via incomplete combustion of fossil fuels and accidental leakage of petroleum products, and as components of products such as creosote (Muckian et al., 2009). Due to PAHs carcinogenic activity, they have been included in the European Union (EU) and the Environmental Protection Agency (EPA) priority pollutant lists. Human exposure to PAHs occurs in three ways, inhalation, dermal contact and consumption of contaminated foods, which account for 88-98% of such contamination; in other words, diet is the major source of human exposure to these contaminants (Rey-Salgueiro et al., 2008). Both the World Health Organization and the UK Expert Panel on Air Quality Standards (EPAQS) have considered benzo(a)pyrene (BaP) as a marker of the carcinogenic potency of the polycyclic aromatic hydrocarbons (PAH) mixture (Delgado-Saborit et al., 2011). Polycyclic aromatic and heavier aliphatic hydrocarbons, which have a stable recalcitrant molecular structure, exhibit high hydrophobicity and low aqueous solubility, are not readily removed from soil through leaching and volatilization (Brassington et al., 2007). The hydrophobicity of PAHs limits desorption to the aqueous phase (Donlon et al., 2002). Six main ways of dissipation, i.e. disappearance, are recognized in the environment: volatilization, photooxidation, Aim of the Work chemical oxidation, sorption, leaching and biodegradation. Microbial degradation is considered to be the main process involved in the dissipation of PAH (Yuan et al., 2002). Thus, more and more research interests are turning to the biodegradation of PAHs. Some microorganisms can utilize PAHs as a source of carbon and energy so that PAHs can be degraded to carbon dioxide and water, or transformed to other nontoxic or low-toxic substances (Perelo, 2010). Compared with other physical and chemical methods such as combustion

  2. Unique gas and hydrocarbon adsorption in a highly porous metal-organic framework made of extended aliphatic ligands.

    Science.gov (United States)

    Li, Kunhao; Lee, Jeongyong; Olson, David H; Emge, Thomas J; Bi, Wenhua; Eibling, Matthew J; Li, Jing

    2008-12-14

    High and unique gas and hydrocarbon adsorption in a highly stable guest-free microporous metal-organic framework constructed on rigid aliphatic ligands, H(2)bodc and ted, is reported in this work. PMID:19082093

  3. Olfactory discrimination ability for aliphatic esters in squirrel monkeys and humans.

    Science.gov (United States)

    Laska, M; Freyer, D

    1997-08-01

    Using a behavioral paradigm designed to simulate olfactory-guided foraging, the ability of five squirrel monkeys to distinguish iso-amyl acetate from n- and iso-forms of other acetic esters (ethyl acetate to decyl acetate) and from other esters carrying the iso-amyl group (iso-amyl propionate to iso-amyl capronate) was investigated. We found (i) that all five animals were clearly able to discriminate between all odor pairs tested; (ii) a significant negative correlation between discrimination performance and structural similarity of odorants in terms of differences in carbon chain length of both the aliphatic alcohol group and the aliphatic acid group of the esters; and (iii) that iso- and n-amyl acetate were perceived as qualitatively similar despite different steric conformation. Using a triple-forced choice procedure, 20 human subjects were tested on the same tasks in parallel and showed a very similar pattern of discrimination performance compared with the squirrel monkeys. Thus, the results of this study provide evidence of well-developed olfactory discrimination ability in squirrel monkeys for aliphatic esters and support the assumption that human and non-human primates may share common principles of odor quality perception. PMID:9279468

  4. The influence of chemical composition of aliphatic-aromatic copolyesters on their properties

    Energy Technology Data Exchange (ETDEWEB)

    Wojtczak, Malgorzata; Galeski, Andrzej; Piorkowska, Ewa [Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, 90-363 Lodz (Poland); Dutkiewicz, Slawomir [Institute of Biopolymers and Chemical Fibres, Marii Sklodowskiej-Curie 19/27, 90-570 Lodz (Poland)

    2014-05-15

    The chain microstructure and properties of a series of aliphatic-aromatic copolyesters in a range of compositions from 10 to 100% of aromatic components were studied by examining melting and crystallization behaviors, dynamic mechanical response, morphology, wide- (WAXS) and small-angle X-ray scattering (SAXS), and tensile deformation. Chain microstructure was analyzed by {sup 1}H NMR. The results indicate that most of copolyesters used in this study have essentially random distribution of comonomers. Copolyesters with more than 30 mol% of aromatic part crystallize with a crystal structure characteristic for homopolymer poly(butylene terephthalate) (PBT). However, some of the reflections from crystal planes are shifted towards lower diffraction angles as compared to butylene terephthalate homoplymer. The phase transition temperatures decrease with increasing aliphatic content. By means of polarized light microscopy (PLM), small-angle light scattering (SALS) and SAXS, crystallization behavior of a selected aliphatic-aromatic copolyester was further explored. Selected copolyester crystallizes in the form of thin fibrous crystals, few nanometers thick, which is the main factor influencing the depression of its melting temperature.

  5. Kinetics of acid-catalyzed aldol condensation reactions of aliphatic aldehydes

    Science.gov (United States)

    Casale, Mia T.; Richman, Aviva R.; Elrod, Matthew J.; Garland, Rebecca M.; Beaver, Melinda R.; Tolbert, Margaret A.

    Field observations of atmospheric aerosols have established that organic compounds compose a large fraction of the atmospheric aerosol mass. However, the physical/chemical pathway by which organic compounds are incorporated into atmospheric aerosols remains unclear. The potential role of acid-catalyzed reactions of organic compounds on acidic aerosols has been explored as a possible chemical pathway for the incorporation of organic material into aerosols. In the present study, ultraviolet-visible (UV-vis) spectroscopy was used to monitor the kinetics of formation of the products of the acid-catalyzed aldol condensation reaction of a range of aliphatic aldehydes (C 2-C 8). The experiments were carried out at various sulfuric acid concentrations and a range of temperatures in order to estimate the rate constants of such reactions on sulfuric acid aerosols under tropospheric conditions. The rate constants were generally found to decrease as the chain length of the aliphatic aldehyde increased (except for acetaldehyde, which had an unusually small rate constant), increase as a function of sulfuric acid concentration as predicted by excess acidity theory, and showed normal Arrhenius behavior as a function of temperature. While the kinetic data are generally consistent with previous laboratory reports of aldehyde reactivity in various sulfuric acid media, the aldol condensation reactions involving aliphatic aldehydes do not appear fast enough to be responsible for significant transfer of organic material into atmospheric aerosols.

  6. Identification of micro-pollutant sources in urban areas. Advantage of aliphatic hydrocarbons

    International Nuclear Information System (INIS)

    In urban areas, important amounts of hydrocarbons are released in the environment and a significant part of these pollutants concentrate in the sewage system leading to environmental problems. Many studies are based only on the study of polycyclic aromatic hydrocarbons (PAH) to identify the origin of environmental contamination. This work aims at demonstrating the advantage of aliphatic hydrocarbons (n-alkanes) in the identification of pollutant sources in urban environments. Their specificity and relative distribution allow the identification and follow up of many hydrocarbon generating sources. The analysis of aliphatic hydrocarbon pathways has permitted to build up an important database for the signature of these pollutants. The coarse fraction of the sewage sludges is mainly contaminated by exhaust particulates and lubricating oils, while the organic fraction and the bio-film concentrate the biological and petroleum product contributions. The estimation of the level of degradation of aliphatic hydrocarbons indicates a shorter residence time in the organic and bio-film layer with respect to the coarse deposit. (J.S.)

  7. Aliphatic, cyclic, and aromatic organic acids, vitamins, and carbohydrates in soil: a review.

    Science.gov (United States)

    Vranova, Valerie; Rejsek, Klement; Formanek, Pavel

    2013-01-01

    Organic acids, vitamins, and carbohydrates represent important organic compounds in soil. Aliphatic, cyclic, and aromatic organic acids play important roles in rhizosphere ecology, pedogenesis, food-web interactions, and decontamination of sites polluted by heavy metals and organic pollutants. Carbohydrates in soils can be used to estimate changes of soil organic matter due to management practices, whereas vitamins may play an important role in soil biological and biochemical processes. The aim of this work is to review current knowledge on aliphatic, cyclic, and aromatic organic acids, vitamins, and carbohydrates in soil and to identify directions for future research. Assessments of organic acids (aliphatic, cyclic, and aromatic) and carbohydrates, including their behaviour, have been reported in many works. However, knowledge on the occurrence and behaviour of D-enantiomers of organic acids, which may be abundant in soil, is currently lacking. Also, identification of the impact and mechanisms of environmental factors, such as soil water content, on carbohydrate status within soil organic matter remains to be determined. Finally, the occurrence of vitamins in soil and their role in biological and biochemical soil processes represent an important direction for future research.

  8. Fast neutron radiography using photoluminescent imaging plates

    International Nuclear Information System (INIS)

    Fast neutron radiography (FNR) and resonance neutron radiography (RNR) are complementary to the conventional radiography with high energy gamma-rays or brems-strahlung radiation used for the inspection of thick metal objects. In both non-destructive methods, the contrast sensitivity and the penetration power can be improved by using higher energy neutrons. At present direct techniques based either n Solid State Nuclear Track detectors (SSNTDs) or scintillating screens and transfer techniques using activation threshold detectors and radiographic films are applied for the detection of fast neutron images. Rather low detection sensitivity of film and SSNTD based fast neutron imaging methods and also rather poor inherent image contrast of SSNTD pose a problem for FNR in the fast neutron energy region 1-15 MeV interesting for NDT. For more efficient detection of fast neutron images the use of novel highly sensitive photoluminescent imaging plates (IP) in combination with threshold at the KFKI research reactor. The conventional IP produced by FUJI Photo Film Co. for the detection of beta and X-ray radiation were used. The threshold activation detectors were the reactions 115In(n, n') 115mIn, 64Zn(n,p) 64Cu, 56Fe(n, p)56Mn, 24Mg(n, p)24Na and 27Al(n, α)24Na. These threshold reactions cover the fast neutron energy region between 0,7 MeV and 12 MeV. Pure, commercially available metals 0,1 mm to 0,25 mm thick made of In, Zn, Fe, Mg and Al were used as converter screens. The very high sensitivity of IP, the linearity of their response over 5 decades of exposure dose and the high dynamic digitalisation latitude enabled fast neutron radiography of image quality comparable to the quality of thermal NR. In our experimental conditions (φn∼ 108 n/cm2s, RCd ∼ 2) the neutron exposure and IP exposure periods were still practical and comparable to the half life of the corresponding reaction products (half an hour to several hours). Even with the 27Al(n.α)24Na reaction having a

  9. CYP79F1 and CYP79F2 have distinct functions in the biosynthesis of aliphatic glucosinolates in Arabidopsis.

    Science.gov (United States)

    Chen, Sixue; Glawischnig, Erich; Jørgensen, Kirsten; Naur, Peter; Jørgensen, Bodil; Olsen, Carl-Erik; Hansen, Carsten H; Rasmussen, Hasse; Pickett, John A; Halkier, Barbara A

    2003-03-01

    Cytochromes P450 of the CYP79 family catalyze the conversion of amino acids to oximes in the biosynthesis of glucosinolates, a group of natural plant products known to be involved in plant defense and as a source of flavor compounds, cancer-preventing agents and bioherbicides. We report a detailed biochemical analysis of the substrate specificity and kinetics of CYP79F1 and CYP79F2, two cytochromes P450 involved in the biosynthesis of aliphatic glucosinolates in Arabidopsis thaliana. Using recombinant CYP79F1 and CYP79F2 expressed in Escherichia coli and Saccharomyces cerevisiae, respectively, we show that CYP79F1 metabolizes mono- to hexahomomethionine, resulting in both short- and long-chain aliphatic glucosinolates. In contrast, CYP79F2 exclusively metabolizes long-chain elongated penta- and hexahomomethionines. CYP79F1 and CYP79F2 are spatially and developmentally regulated, with different gene expression patterns. CYP79F2 is highly expressed in hypocotyl and roots, whereas CYP79F1 is strongly expressed in cotyledons, rosette leaves, stems, and siliques. A transposon-tagged CYP79F1 knockout mutant completely lacks short-chain aliphatic glucosinolates, but has an increased level of long-chain aliphatic glucosinolates, especially in leaves and seeds. The level of long-chain aliphatic glucosinolates in a transposon-tagged CYP79F2 knockout mutant is substantially reduced, whereas the level of short-chain aliphatic glucosinolates is not affected. Biochemical characterization of CYP79F1 and CYP79F2, and gene expression analysis, combined with glucosinolate profiling of knockout mutants demonstrate the functional role of these enzymes. This provides valuable insights into the metabolic network leading to the biosynthesis of aliphatic glucosinolates, and into metabolic engineering of altered aliphatic glucosinolate profiles to improve nutritional value and pest resistance. PMID:12609033

  10. Development of mold for biodegradable materials

    Energy Technology Data Exchange (ETDEWEB)

    Japitana, F.H.; Jabrica, A.M. [Metals Industry Research and Develeopment Center, Manila (Philippines). Dept. of Science and Technology; Komatsu, M. [Komatsu Consulting Engineer Office, Iwaki City, Fukushima (Japan); Takeuchi, Y. [Osaka Univ., Osaka (Japan). Dept. of Mechanical Engineering

    2008-07-01

    The improper disposal of non-biodegradable plastics adversely affect global environmental factors, principles of sustainability, industrial ecology and ecoefficiency. Therefore, a new generation of bio-based polymeric products has been developed. These polylactides (PLA), cellulose esters, starch plastics and polyhydroxyalkanoates (PHAs) are made from renewable natural resources and are biodegradable. They meet environmental conditions and can compete with their petrochemical counterparts. Among them, PLA is particularly attractive as a sustainable alternative to synthetic polymers and a potential candidate for the fabrication of biocomposites. Certain blends have proved successful in medical implants, sutures and drug delivery systems because of their capacity to dissolve away with time. However, widespread use of PLA is limited because of cost. Biodegradable plastic products are currently 6 to 10 times more expensive than traditional plastics. Environmentalists argue that the cheaper price of traditional plastics does not reflect their true cost when their impact is considered. This paper presented a solution to reduce the production cost of biodegradable plastics. In particular, it described a newly developed plastic injection mold for biodegradable materials which can produce a scrapless product. The system reduces processing time because it is not necessary to remove any gating or runners after the injection process. Takeout robots ensure that the quality of the product is maintained. 12 figs.

  11. Bio-Degradable Plastics Impact On Environment

    Directory of Open Access Journals (Sweden)

    T.SUBRAMANI

    2014-06-01

    Full Text Available The potential of biodegradable polymers and more particularly that of polymers obtained from renewable resources such as the polysaccharides (e.g., starch have long been recognized. However, these biodegradable polymers have been largely used in some applications (e.g., food industry and have not found extensive applications in the packaging industries to replace conventional plastic materials, although they could be an interesting way to overcome the limitation of the petrochemical resources in the future. The fossil fuel and gas could be partially replaced by greener agricultural sources, which should participate in the reduction of CO2 emissions. Bio-based and biodegradable plastics can form the basis for environmentally preferable, sustainable alternative to current materials based exclusively on petroleum feed stocks. These bio-based materials offer value in the sustainability/life-cycle equation by being a part of the biological carbon cycle, especially as it relates to carbon-based polymeric materials such as plastics, water soluble polymers and other carbon based products like lubricants, biodiesel, and detergents. Identification and quantification of bio based content uses radioactive C-14 signature. Biopolymers are generally capable of being utilized by living matter (biodegraded, and so can be disposed in safe and ecologically sound ways through disposal processes (waste management like composting, soil application, and biological wastewater treatment. Single use, short-life, disposable products can be engineered to be bio-based and biodegradable.

  12. Biodegradability of degradable plastic waste.

    Science.gov (United States)

    Agamuthu, P; Faizura, Putri Nadzrul

    2005-04-01

    Plastic waste constitutes the third largest waste volume in Malaysian municipal solid waste (MSW), next to putrescible waste and paper. The plastic component in MSW from Kuala Lumpur averages 24% (by weight), whereas the national mean is about 15%. The 144 waste dumps in the country receive about 95% of the MSW, including plastic waste. The useful life of the landfills is fast diminishing as the plastic waste stays un-degraded for more than 50 years. In this study the compostability of polyethylene and pro-oxidant additive-based environmentally degradable plastics (EDP) was investigated. Linear low-density polyethylene (LLDPE) samples exposed hydrolytically or oxidatively at 60 degrees C showed that the abiotic degradation path was oxidative rather than hydrolytic. There was a weight loss of 8% and the plastic has been oxidized as shown by the additional carbonyl group exhibited in the Fourier transform infra red (FTIR) Spectrum. Oxidation rate seemed to be influenced by the amount of pro-oxidant additive, the chemical structure and morphology of the plastic samples, and the surface area. Composting studies during a 45-day experiment showed that the percentage elongation (reduction) was 20% for McD samples [high-density polyethylene, (HDPE) with 3% additive] and LL samples (LLDPE with 7% additive) and 18% reduction for totally degradable plastic (TDP) samples (HDPE with 3% additive). Lastly, microbial experiments using Pseudomonas aeroginosa on carbon-free media with degradable plastic samples as the sole carbon source, showed confirmatory results. A positive bacterial growth and a weight loss of 2.2% for degraded polyethylene samples were evident to show that the degradable plastic is biodegradable.

  13. Steady-state photoluminescent excitation characterization of semiconductor carrier recombination

    Science.gov (United States)

    Bhosale, J. S.; Moore, J. E.; Wang, X.; Bermel, P.; Lundstrom, M. S.

    2016-01-01

    Photoluminescence excitation spectroscopy is a contactless characterization technique that can provide valuable information about the surface and bulk recombination parameters of a semiconductor device, distinct from other sorts of photoluminescent measurements. For this technique, a temperature-tuned light emitting diode (LED) has several advantages over other light sources. The large radiation density offered by LEDs from near-infrared to ultraviolet region at a low cost enables efficient and fast photoluminescence measurements. A simple and inexpensive LED-based setup facilitates measurement of surface recombination velocity and bulk Shockley-Read-Hall lifetime, which are key parameters to assess device performance. Under the right conditions, this technique can also provide a contactless way to measure the external quantum efficiency of a solar cell.

  14. Dynamics of multi-photon photoluminescence in gold nanoantennas

    CERN Document Server

    Biagioni, P; Huang, J -S; Kern, J; Duò, L; Hecht, B; Finazzi, M; Cerullo, G

    2011-01-01

    We perform a combined study of the degree of nonlinearity and the temporal dynamics of multiphoton-excited photoluminescence (MPPL) in gold nanoantennas. At variance with standard gold two-photon photoluminescence (TPPL), the large photoluminescence enhancement in resonant nanostructures is sometimes found to involve more than two absorbed photons per emitted photon. By two-pulse correlation measurements of TPPL and MPPL we are able to address the particular dynamics of these mechanisms. Our data give direct evidence for the two-step model that has been proposed for gold TPPL and suggest that MPPL is characterized by very similar dynamics. Interestingly, for resonant antennas we observe a reduced MPPL relaxation time compared to off-resonant antennas.

  15. Chemical modification and the photoluminescence stabilization of titanic acid nanotubes

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Xingtang; WANG; Yumei; ZHANG; Chunmei; JIANG; Xiaohong; TIAN; Baoli; LI; Yuncai; HUANG; Yabin

    2006-01-01

    Titanic acid nanotubes (H2Ti2O4(OH)2) were surface-modified with cetyl alcohol through dehydration reaction because of existence of Ti-OH. The modified nanotubes were characterized by transmission electron microscopy (TEM), Fourier Transform Infrared (FT-IR) spectrometry and photoluminescence (PL) spectra. The results indicate that the modified nanotubes can be easily dispersed into organic solvent such as chloroform and toluene in contrast with the unmodified nanotubes, which makes it easier to be assembled by LB technique. Moreover, the Ti-O-CH2(CH2)14CH3 on the surface of the nanotubes can hinder the adsorption of water and consequently the photoluminescence property of the nanotubes can be stabilized. Even though kept in humid condition or in air for a long time, the modified nanotubes also maintain the special photoluminescence property in the visible region.

  16. Steady-state photoluminescent excitation characterization of semiconductor carrier recombination

    Energy Technology Data Exchange (ETDEWEB)

    Bhosale, J. S. [Intel Corporation, Hillsboro, Oregon 97124 (United States); Department of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); Moore, J. E.; Wang, X.; Bermel, P.; Lundstrom, M. S. [Department of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907 (United States)

    2016-01-15

    Photoluminescence excitation spectroscopy is a contactless characterization technique that can provide valuable information about the surface and bulk recombination parameters of a semiconductor device, distinct from other sorts of photoluminescent measurements. For this technique, a temperature-tuned light emitting diode (LED) has several advantages over other light sources. The large radiation density offered by LEDs from near-infrared to ultraviolet region at a low cost enables efficient and fast photoluminescence measurements. A simple and inexpensive LED-based setup facilitates measurement of surface recombination velocity and bulk Shockley-Read-Hall lifetime, which are key parameters to assess device performance. Under the right conditions, this technique can also provide a contactless way to measure the external quantum efficiency of a solar cell.

  17. Steady-state photoluminescent excitation characterization of semiconductor carrier recombination

    International Nuclear Information System (INIS)

    Photoluminescence excitation spectroscopy is a contactless characterization technique that can provide valuable information about the surface and bulk recombination parameters of a semiconductor device, distinct from other sorts of photoluminescent measurements. For this technique, a temperature-tuned light emitting diode (LED) has several advantages over other light sources. The large radiation density offered by LEDs from near-infrared to ultraviolet region at a low cost enables efficient and fast photoluminescence measurements. A simple and inexpensive LED-based setup facilitates measurement of surface recombination velocity and bulk Shockley-Read-Hall lifetime, which are key parameters to assess device performance. Under the right conditions, this technique can also provide a contactless way to measure the external quantum efficiency of a solar cell

  18. The effects of biodegradation on the compositions of aromatic hydrocarbons and maturity indicators in biodegraded oils from Liaohe Basin

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    By the aid of GC-MS technique,a series of sequentially biodegraded oils from Liaohe Basin have been analyzed. The results show that the concentrations and relative compositions of various aromatic compounds in the biodegraded crude oils will change with increasing biodegradation degree. The concentrations of alkyl naphthalenes,alkyl phenanthrenes,alkyl dibenzothiophene are decreased,and the concentration of triaromatic steroids will increase with increasing biodegradation degree in biodegraded oils. Those phenomena indicate that various aromatic compounds are more easily biodegraded by bacteria like other kinds of hydrocarbons such as alkanes,but different series of aromatic compounds have a varied ability to resistant to biodegradation. The ratios of dibenzothiophene to phenenthrene(DBTH/P) and methyl dibenzothiophene to methyl phenanthrene(MDBTH/MP) are related to the features of depositional environment for source rocks such as redox and ancient salinity. However,in biodegraded oils,the two ratios increase quickly with the increase of the biodegradation degree,indicating that they have lost their geochemical significance. In this case,they could not be used to evaluate the features of depositional environment. Methyl phenanthrene index,methyl phenanthrene ratio and methyl dibenzoyhiophene ratio are useful aromatic maturity indicators for the crude oils and the source rocks without vitrinite. But for biodegraded oils,those aromatic maturity indicators will be affected by biodegradation and decrease with the increase of the biodegradation degree. Therefore,those aromatic molecular maturity indicators could not be used for biodegraded oils.

  19. Introduction of environmentally degradable parameters to evaluate the biodegradability of biodegradable polymers.

    Directory of Open Access Journals (Sweden)

    Wenbin Guo

    Full Text Available Environmentally Degradable Parameter ((EdK is of importance in the describing of biodegradability of environmentally biodegradable polymers (BDPs. In this study, a concept (EdK was introduced. A test procedure of using the ISO 14852 method and detecting the evolved carbon dioxide as an analytical parameter was developed, and the calculated (EdK was used as an indicator for the ultimate biodegradability of materials. Starch and polyethylene used as reference materials were defined as the (EdK values of 100 and 0, respectively. Natural soil samples were inoculated into bioreactors, followed by determining the rates of biodegradation of the reference materials and 15 commercial BDPs over a 2-week test period. Finally, a formula was deduced to calculate the value of (EdK for each material. The (EdK values of the tested materials have a positive correlation to their biodegradation rates in the simulated soil environment, and they indicated the relative biodegradation rate of each material among all the tested materials. Therefore, the (EdK was shown to be a reliable indicator for quantitatively evaluating the potential biodegradability of BDPs in the natural environment.

  20. Modulation of mixed-phase titania photoluminescence by oxygen adsorption

    International Nuclear Information System (INIS)

    We investigate the effect of oxygen (O2) adsorption on photoluminescence properties of mixed-phase titania nanoparticle films deposited by femtosecond pulsed laser deposition, aiming to assess preliminary conclusions about the feasibility of opto-chemical sensing based on titania. We evidence that O2 produces opposite responses in rutile and anatase photoluminescence efficiency, highlighting interesting potentialities for future double-parametric optical sensing based on titania. The results evidence an important role of lattice oxygen atoms, suggesting that the standard Schottky barrier mechanism driving the response toward gas species in most used metal-oxide sensors (e.g., tin dioxide) is not the only active mechanism in titania.

  1. Observation of nitrogen vacancy photoluminescence from an optically levitated nanodiamond

    CERN Document Server

    Neukirch, Levi P; Quidant, Romain; Novotny, Lukas; Vamivakas, A Nick

    2013-01-01

    We present the first evidence of nitrogen vacancy (NV) photoluminescence from a nanodiamond suspended in a free-space optical dipole trap at atmospheric pressure. The photoluminescence rates are shown to decrease with increasing trap laser power, but are inconsistent with a thermal quenching process. For a continuous-wave trap, the neutral charge state (NV$^0$) appears to be suppressed. Chopping the trap laser yields higher total count rates and results in a mixture of both NV$^0$ and the negative charge state (NV$^-$).

  2. Photoluminescence of Eu2+ Doped ZnS Nanocrystals

    Institute of Scientific and Technical Information of China (English)

    LIU Shu-Man; GUO Hai-Qing; ZHANG Zhi-Hua; LIU Feng-Qi; WANG Zhan-Guo

    2000-01-01

    Eu2+ doped ZnS nanocrystals exhibit new luminescence properties because of the enlarged energy gap of nanocrys talline ZnS host due to quantum confinement effects. Photoluminescence emission at about 520nm from Eu2+ doped ZnS nanocrystals at room temperature is investigated by using photoluminescence emission and excitation spectroscopy. Such green emission with long lifetime (ms) is proposed to be a result of excitation, ionization, carriers recapture and recombination via Eu2+ centers in nanocrystalline ZnS host.

  3. Optical enhancement of photoluminescence with colloidal quantum dots

    Science.gov (United States)

    Abraham, Gabrielle; French, David A.; Bajwa, Pooja; Heyes, Colin D.; Herzog, Joseph B.

    2015-08-01

    This work investigates colloidal, semiconductor Cadmium Selenide (CdSe) QDs with optical spectroscopy measurements. A custom-built microscope has been used for photoluminescence spectroscopy and has collected images, videos, and spectra of samples to study the effects of substrates, sample density, uniformity, and QD aging with time. This set up will be used to detect single to a few molecules, shown by fluorescent intermittency, or QD blinking. Differences in the spectrum will be noted as related to the age of samples, the density of the quantum dots, and the concentration of samples. Further experiments include the potential plasmonic enhancement of QD photoluminescence by gold nanoparticles or nanostructures.

  4. Terahertz-field-induced photoluminescence of nanostructured gold films

    DEFF Research Database (Denmark)

    Iwaszczuk, Krzysztof; Malureanu, Radu; Zalkovskij, Maksim;

    2013-01-01

    We experimentally demonstrate photoluminescence from nanostructured ultrathin gold films subjected to strong single-cycle terahertz transients with peak electric field over 300 kV/cm. We show that UV-Vis-NIR light is being generated and the efficiency of the process is strongly enhanced at the pe......We experimentally demonstrate photoluminescence from nanostructured ultrathin gold films subjected to strong single-cycle terahertz transients with peak electric field over 300 kV/cm. We show that UV-Vis-NIR light is being generated and the efficiency of the process is strongly enhanced...

  5. Biodegradable Materials for Bone Repairs: A Review

    Institute of Scientific and Technical Information of China (English)

    Lili Tan; Xiaoming Yu; Peng Wan; Ke Yang

    2013-01-01

    With attractive research and development of biomaterials,more and more opportunities have been brought to the treatments of human tissue repairs.The implant is usually no need to exist in the body accompanied with the recovery or regeneration of the tissue lesions,and the long-term effect of exotic substance to human body should be reduced as lower as possible.For this purpose,biodegradable materials,including polymers,magnesium alloys and ceramics,have attracted much attention for medical applications due to their biodegradable characters in body environment.This paper in turn introduces these three different types of widely studied biodegradable materials as well as their advantages as implants in applications for bone repairs.Relevant history and research progresses are summarized.

  6. Biodegradable nanoparticles for gene therapy technology

    Energy Technology Data Exchange (ETDEWEB)

    Hosseinkhani, Hossein, E-mail: hosseinkhani@mail.ntust.edu.tw; He, Wen-Jie [National Taiwan University of Science and Technology (Taiwan Tech), Graduate Institute of Biomedical Engineering (China); Chiang, Chiao-Hsi [School of Pharmacy, National Defense Medical Center (China); Hong, Po-Da [National Taiwan University of Science and Technology (Taiwan Tech), Graduate Institute of Biomedical Engineering (China); Yu, Dah-Shyong [Nanomedicine Research Center, National Defense Medical Center (China); Domb, Abraham J. [The Hebrew University of Jerusalem, Institute of Drug Research, School of Pharmacy, Faculty of Medicine, Center for Nanoscience and Nanotechnology and The Alex Grass Center for Drug Design and Synthesis (Israel); Ou, Keng-Liang [College of Oral Medicine, Taipei Medical University, Research Center for Biomedical Devices and Prototyping Production (China)

    2013-07-15

    Rapid propagations in materials technology together with biology have initiated great hopes in the possibility of treating many diseases by gene therapy technology. Viral and non-viral gene carriers are currently applied for gene delivery. Non-viral technology is safe and effective for the delivery of genetic materials to cells and tissues. Non-viral systems are based on plasmid expression containing a gene encoding a therapeutic protein and synthetic biodegradable nanoparticles as a safe carrier of gene. Biodegradable nanoparticles have shown great interest in drug and gene delivery systems as they are easy to be synthesized and have no side effect in cells and tissues. This review provides a critical view of applications of biodegradable nanoparticles on gene therapy technology to enhance the localization of in vitro and in vivo and improve the function of administered genes.

  7. Biodegradable nanoparticles for gene therapy technology

    International Nuclear Information System (INIS)

    Rapid propagations in materials technology together with biology have initiated great hopes in the possibility of treating many diseases by gene therapy technology. Viral and non-viral gene carriers are currently applied for gene delivery. Non-viral technology is safe and effective for the delivery of genetic materials to cells and tissues. Non-viral systems are based on plasmid expression containing a gene encoding a therapeutic protein and synthetic biodegradable nanoparticles as a safe carrier of gene. Biodegradable nanoparticles have shown great interest in drug and gene delivery systems as they are easy to be synthesized and have no side effect in cells and tissues. This review provides a critical view of applications of biodegradable nanoparticles on gene therapy technology to enhance the localization of in vitro and in vivo and improve the function of administered genes

  8. Petroleum biodegradation and oil spill bioremediation

    International Nuclear Information System (INIS)

    Hydrocarbon-utilizing microorganisms are ubiquitously distributed in the marine environment following oil spills. These microorganisms naturally biodegrade numerous contaminating petroleum hydrocarbons, thereby cleansing the oceans of oil pullutants. Bioremediation, which is accomplished by adding exogenous microbial populations or stimulating indigenous ones, attempts to raise the rates of degradation found naturally to significantly higher rates. Seeding with oil degraders has not been demonstrated to be effective, but addition of nitrogenous fertilizers has been shown to increase rates of petroleum biodegradation. In the case of the Exxon Valdez spill, the largest and most thoroughly studied application of bioremediation, the application of fertilizer (slow release or oleophilic) increased rates of biodegradation 3-5 times. Because of the patchiness of oil, an internally conserved compound, hopane, was critical for demonstrating the efficacy of bioremediation. Multiple regression models showed that the effectiveness of bioremediation depended upon the amount of nitrogen delivered, the concentration of oil, and time. (author)

  9. Biodegradation of malachite green by Ochrobactrum sp.

    Science.gov (United States)

    Vijayalakshmidevi, S R; Muthukumar, Karuppan

    2014-02-01

    This study presents the biodegradation of malachite green (MG), a triphenylmethane dye, using a novel microorganism isolated from textile effluent contaminated environment. The organism responsible for degradation was identified as Ochrobactrum sp JN214485 by 16S rRNA analysis. The effect of operating parameters such as temperature, pH, immobilized bead loading, and initial dye concentration on % degradation was studied, and their optimal values were found to be 30 °C, 6, 20 g/L and 100 mg/L, respectively. The analysis showed that the extracellular enzymes were responsible for the degradation. The biodegradation of MG was confirmed by UV-visible spectroscopic and FTIR analysis. The phytotoxicity test concluded that the degradation products were less toxic compared to MG. The kinetics of biodegradation was studied and the activation energy was found to be 10.65 kcal/mol.

  10. Biodegradable Photonic Melanoidin for Theranostic Applications.

    Science.gov (United States)

    Lee, Min-Young; Lee, Changho; Jung, Ho Sang; Jeon, Mansik; Kim, Ki Su; Yun, Seok Hyun; Kim, Chulhong; Hahn, Sei Kwang

    2016-01-26

    Light-absorbing nanoparticles for localized heat generation in tissues have various biomedical applications in diagnostic imaging, surgery, and therapies. Although numerous plasmonic and carbon-based nanoparticles with strong optical absorption have been developed, their clearance, potential cytotoxicity, and long-term safety issues remain unresolved. Here, we show that "generally regarded as safe (GRAS)" melanoidins prepared from glucose and amino acid offer a high light-to-heat conversion efficiency, biocompatibility, biodegradability, nonmutagenicity, and efficient renal clearance, as well as a low cost for synthesis. We exhibit a wide range of biomedical photonic applications of melanoidins, including in vivo photoacoustic mapping of sentinel lymph nodes, photoacoustic tracking of gastrointestinal tracts, photothermal cancer therapy, and photothermal lipolysis. The biodegradation rate and renal clearance of melanoidins are controllable by design. Our results confirm the feasibility of biodegradable melanoidins for various photonic applications to theranostic nanomedicines. PMID:26623481

  11. Biodegradation of creosote compounds: Comparison of experiments at different scales

    DEFF Research Database (Denmark)

    Broholm, K.; Arvin, Erik

    2001-01-01

    This paper compares the results of biodegradation experiments with creosote compounds performed at different scales. The experiments include field observations, field experiments, large-scale intact laboratory column experiments, model fracture experiments, and batch experiments. Most of the expe...... of the pyrroles on the biodegradation of benzene, and the biodegradation of benzothiophene occurs only in the presence of a primary substrate. The experiments show that some biodegradation processes of organic compounds may be common to different microorganisms....

  12. Biodegradable containers from green waste materials

    Science.gov (United States)

    Sartore, Luciana; Schettini, Evelia; Pandini, Stefano; Bignotti, Fabio; Vox, Giuliano; D'Amore, Alberto

    2016-05-01

    Novel biodegradable polymeric materials based on protein hydrolysate (PH), derived from waste products of the leather industry, and poly(ethylene glycol) diglycidyl ether (PEG) or epoxidized soybean oil (ESO) were obtained and their physico-chemical properties and mechanical behaviour were evaluated. Different processing conditions and the introduction of fillers of natural origin, as saw dust and wood flour, were used to tailor the mechanical properties and the environmental durability of the product. The biodegradable products, which are almost completely manufactured from renewable-based raw materials, look promising for several applications, particularly in agriculture for the additional fertilizing action of PH or in packaging.

  13. Soluble Eggshell Mebrane Protein:Antibacterial Property and Biodegradability

    Institute of Scientific and Technical Information of China (English)

    YI Feng; YU Jian; LI Qiang; GUO Zhaoxia

    2007-01-01

    The antibacterial property and biodegradability of soluble eggshell membrane protein (SEP)are reported. Unlike the natural eggshell membrane (ESM), SEP does not possess antibacterial property against E.coli. The biodegradation tests with trypsin show that both ESM and SEP are biodegradable.

  14. Biodegradation of Synthetic Polyesters (BTA and PCL with Natural Flora in Soil Burial and Pure Cultures under Ambient Temperature

    Directory of Open Access Journals (Sweden)

    Mona K. Gouda

    2012-03-01

    Full Text Available The aim of this study was to study the biodegradation of two synthetic polyesters, one aliphaticaromatic (1, 4-butanediol, terephthalic-adipic acid, BTA and the other aliphatic (poly (,-caprolactone, PCL, under different soil types (canal shore soil, garden soil, compost and Peat moss, respectively, as well as using locally isolated cultures at ambient temperature. The results showed that the BTA films buried in canal shore and garden soil were degraded faster than that in the other soils. After six weeks about 90, 88 and 80% were degraded in garden, canal shore soil and compost respectively, while only 52% were degraded in Peat moss. On the other hand, 95 and 93% weight loss was obtained for PCL films buried for three weeks in canal shore and garden soil respectively. The Scanning Electron Microscope photos confirm the results of weight loss and revealed the presence of cracks and fungal growth on films buried in different soils. The results with pure cultures, especially with Fusarium solani, also confirmed the biodegradability of two polyesters under ambient temperature. Finally, it could be concluded that both synthetic polyester are degradable under ambient conditions.

  15. Biodegradation of Leonardite by an alkali-producing bacterial community and characterization of the degraded products.

    Science.gov (United States)

    Gao, Tong-Guo; Jiang, Feng; Yang, Jin-Shui; Li, Bao-Zhen; Yuan, Hong-Li

    2012-03-01

    In this study, three bacterial communities were obtained from 12 Leonardite samples with the aim of identifying a clean, effective, and economic technique for the dissolution of Leonardite, a type of low-grade coal, in the production of humic acid (HA). The biodegradation ability and characteristics of the degraded products of the most effective bacterial community (MCSL-2), which degraded 50% of the Leonardite within 21 days, were further investigated. Analyses of elemental composition, (13)C NMR, and Fourier transform infrared revealed that the contents of C, O, and aliphatic carbon were similar in biodegraded humic acid (bHA) and chemically (alkali) extracted humic acid (cHA). However, the N and carboxyl carbon contents of bHA was higher than that of cHA. Furthermore, a positive correlation was identified between the degradation efficiency and the increasing pH of the culture medium, while increases of manganese peroxidase and esterase activities were also observed. These data demonstrated that both alkali production and enzyme reactions were involved in Leonardite solubilization by MCSL-2, although the former mechanism predominated. No fungus was observed by microscopy. Only four bacterial phylotypes were recognized, and Bacillus licheniformis-related bacteria were identified as the main group in MCSL-2 by analysis of amplified 16S rRNA genes, thus demonstrating that Leonardite degradation ability has a limited distribution in bacteria. Hormone-like bioactivities of bHA were also detected. In this study, a bacterial community capable of Leonardite degradation was identified and the products characterized. These data implicate the use of such bacteria for the exploitation of Leonardite as a biofertilizer.

  16. Biodegradation of Leonardite by an alkali-producing bacterial community and characterization of the degraded products.

    Science.gov (United States)

    Gao, Tong-Guo; Jiang, Feng; Yang, Jin-Shui; Li, Bao-Zhen; Yuan, Hong-Li

    2012-03-01

    In this study, three bacterial communities were obtained from 12 Leonardite samples with the aim of identifying a clean, effective, and economic technique for the dissolution of Leonardite, a type of low-grade coal, in the production of humic acid (HA). The biodegradation ability and characteristics of the degraded products of the most effective bacterial community (MCSL-2), which degraded 50% of the Leonardite within 21 days, were further investigated. Analyses of elemental composition, (13)C NMR, and Fourier transform infrared revealed that the contents of C, O, and aliphatic carbon were similar in biodegraded humic acid (bHA) and chemically (alkali) extracted humic acid (cHA). However, the N and carboxyl carbon contents of bHA was higher than that of cHA. Furthermore, a positive correlation was identified between the degradation efficiency and the increasing pH of the culture medium, while increases of manganese peroxidase and esterase activities were also observed. These data demonstrated that both alkali production and enzyme reactions were involved in Leonardite solubilization by MCSL-2, although the former mechanism predominated. No fungus was observed by microscopy. Only four bacterial phylotypes were recognized, and Bacillus licheniformis-related bacteria were identified as the main group in MCSL-2 by analysis of amplified 16S rRNA genes, thus demonstrating that Leonardite degradation ability has a limited distribution in bacteria. Hormone-like bioactivities of bHA were also detected. In this study, a bacterial community capable of Leonardite degradation was identified and the products characterized. These data implicate the use of such bacteria for the exploitation of Leonardite as a biofertilizer. PMID:22075634

  17. Effect of sterilization dose on electron beam irradiated biodegradable polymers and coconut fiber based composites

    Energy Technology Data Exchange (ETDEWEB)

    Kodama, Yasko; Machado, Luci D.B., E-mail: ykodama@ipen.b, E-mail: lmachado@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Oishi, Akihiro; Nakayama, Kazuo, E-mail: a.oishi@aist.go.j, E-mail: kazuo-nakayama@jcom.home.ne.j [National Institute of Advanced Industrial Science and Technology (AIST), Ibaraki-ken (Japan). Research Institute for Sustainable Chemical Innovation; Nagasawa, Naotsugu; Tamada, Masao, E-mail: nagasawa.naotsugu@jaea.go.j [Japan Atomic Energy Agency (JAEA), Gunma-ken (Japan). Quantum Beam Science Directorate

    2009-07-01

    In Brazil, annual production of coconut fruit is 1.5 billion in a cultivated area of 2.7 million ha. Coconut fiber applications as reinforcement for polymer composites, besides reducing the coconut waste, would reduce cost of the composite. On the other hand, biodegradable polymers have been receiving much attention due to the plastic waste problem. Poly(e-caprolactone), PCL, and poly(lactic acid), PLA, besides being biodegradable aliphatic polyesters, are biocompatible polymers. Considering the biomedical application of PLA and PCL, their products must be sterilized for use, and ionizing radiation has been widely used for medical devices sterilization. It is important to study the effect of ionizing radiation on the blends and composites due to the fact that they are based on biocompatible polymers. Is this research, hot pressed samples based on PLA:PCL (80:20, ratio of weight:weight) blend and the composites containing chemically treated or untreated coconut fiber (5, 10%) were irradiated by electron beams and gamma radiation from Co-60 source at doses in the range up to 200 kGy. Thermal mechanical analysis (TMA) and gel fraction measurements were performed in irradiated samples. From TMA curves it can be observed that thermal stability of samples with untreated coconut fiber slightly decreased with increasing fiber content. On the other hand, deformation increased with increasing fiber content. Acetylated coconut fibers slightly decreased thermal stability of samples. It seems that no interaction occurs between the natural fibers and the polymeric matrix due to irradiation. PLLA undergoes to main chain scission under ionizing irradiation according to thermal stability results and also because no gel fraction was observed. In contrast, PCL cross-linking is induced by ionizing radiation that increases thermal stability and decreases deformation. (author)

  18. Effect of sterilization dose on electron beam irradiated biodegradable polymers and coconut fiber based composites

    International Nuclear Information System (INIS)

    In Brazil, annual production of coconut fruit is 1.5 billion in a cultivated area of 2.7 million ha. Coconut fiber applications as reinforcement for polymer composites, besides reducing the coconut waste, would reduce cost of the composite. On the other hand, biodegradable polymers have been receiving much attention due to the plastic waste problem. Poly(e-caprolactone), PCL, and poly(lactic acid), PLA, besides being biodegradable aliphatic polyesters, are biocompatible polymers. Considering the biomedical application of PLA and PCL, their products must be sterilized for use, and ionizing radiation has been widely used for medical devices sterilization. It is important to study the effect of ionizing radiation on the blends and composites due to the fact that they are based on biocompatible polymers. Is this research, hot pressed samples based on PLA:PCL (80:20, ratio of weight:weight) blend and the composites containing chemically treated or untreated coconut fiber (5, 10%) were irradiated by electron beams and gamma radiation from Co-60 source at doses in the range up to 200 kGy. Thermal mechanical analysis (TMA) and gel fraction measurements were performed in irradiated samples. From TMA curves it can be observed that thermal stability of samples with untreated coconut fiber slightly decreased with increasing fiber content. On the other hand, deformation increased with increasing fiber content. Acetylated coconut fibers slightly decreased thermal stability of samples. It seems that no interaction occurs between the natural fibers and the polymeric matrix due to irradiation. PLLA undergoes to main chain scission under ionizing irradiation according to thermal stability results and also because no gel fraction was observed. In contrast, PCL cross-linking is induced by ionizing radiation that increases thermal stability and decreases deformation. (author)

  19. Comparative study on the biodegradation and biocompatibility of silicate bioceramic coatings on biodegradable magnesium alloy as biodegradable biomaterial

    Science.gov (United States)

    Razavi, M.; Fathi, M. H.; Savabi, O.; Razavi, S. M.; Hashemibeni, B.; Yazdimamaghani, M.; Vashaee, D.; Tayebi, L.

    2014-03-01

    Many clinical cases as well as in vivo and in vitro assessments have demonstrated that magnesium alloys possess good biocompatibility. Unfortunately, magnesium and its alloys degrade too quickly in physiological media. In order to improve the biodegradation resistance and biocompatibility of a biodegradable magnesium alloy, we have prepared three types of coating include diopside (CaMgSi2O6), akermanite (Ca2MgSi2O6) and bredigite (Ca7MgSi4O16) coating on AZ91 magnesium alloy through a micro-arc oxidation (MAO) and electrophoretic deposition (EPD) method. In this research, the biodegradation and biocompatibility behavior of samples were evaluated in vitro and in vivo. The in vitro analysis was performed by cytocompatibility and MTT-assay and the in vivo test was conducted on the implantation of samples in the greater trochanter of adult rabbits. The results showed that diopside coating has the best bone regeneration and bredigite has the best biodegradation resistance compared to others.

  20. Characterization of a biosurfactant produced by Pseudomonas cepacia CCT6659 in the presence of industrial wastes and its application in the biodegradation of hydrophobic compounds in soil.

    Science.gov (United States)

    Silva, Elias J; Rocha e Silva, Nathália Maria P; Rufino, Raquel D; Luna, Juliana M; Silva, Ricardo O; Sarubbo, Leonie A

    2014-05-01

    The bacterium Pseudomonas cepacia CCT6659 cultivated with 2% soybean waste frying oil and 2% corn steep liquor as substrates produced a biosurfactant with potential application in the bioremediation of soils. The biosurfactant was classified as an anionic biomolecule composed of 75% lipids and 25% carbohydrates. Characterization by proton nuclear magnetic resonance ((1)H and (13)C NMR) revealed the presence of carbonyl, olefinic and aliphatic groups, with typical spectra of lipids. Four sets of biodegradation experiments were carried out with soil contaminated by hydrophobic organic compounds amended with molasses in the presence of an indigenous consortium, as follows: Set 1-soil+bacterial cells; Set 2-soil+biosurfactant; Set 3-soil+bacterial cells+biosurfactant; and Set 4-soil without bacterial cells or biosurfactant (control). Significant oil biodegradation activity (83%) occurred in the first 10 days of the experiments when the biosurfactant and bacterial cells were used together (Set 3), while maximum degradation of the organic compounds (above 95%) was found in Sets 1-3 between 35 and 60 days. It is evident from the results that the biosurfactant alone and its producer species are both capable of promoting biodegradation to a large extent.

  1. Intrinsic Photoluminescence Emission from Subdomained Graphene Quantum Dots.

    Science.gov (United States)

    Yoon, Hyewon; Chang, Yun Hee; Song, Sung Ho; Lee, Eui-Sup; Jin, Sung Hwan; Park, Chanae; Lee, Jinsup; Kim, Bo Hyun; Kang, Hee Jae; Kim, Yong-Hyun; Jeon, Seokwoo

    2016-07-01

    The photoluminescence (PL) origin of bright blue emission arising from intrinsic states in graphene quantum dots (GQDs) is investigated. The bright PL of intercalatively acquired GQDs is attributed to favorably formed subdomains composed of four to seven carbon hexagons. Random and harsh oxidation which hinders the energetically favorable formation of subdomains causes weak and redshifted PL. PMID:27153519

  2. Standards for photoluminescence quantum yield measurements in solution

    NARCIS (Netherlands)

    A.M. Brouwer

    2011-01-01

    The use of standards for the measurement of photoluminescence quantum yields (QYs) in dilute solutions is reviewed. Only three standards can be considered well established. Another group of six standards has been investigated by several independent researchers. A large group of standards is frequent

  3. Photoluminescence studies of single InGaAs quantum dots

    DEFF Research Database (Denmark)

    Leosson, Kristjan; Jensen, Jacob Riis; Hvam, Jørn Märcher

    1999-01-01

    Semiconductor quantum dots are considered a promising material system for future optical devices and quantum computers. We have studied the low-temperature photoluminescence properties of single InGaAs quantum dots embedded in GaAs. The high spatial resolution required for resolving single dots...

  4. Fractals of graphene quantum dots in photoluminescence of shungite

    Science.gov (United States)

    Razbirin, B. S.; Rozhkova, N. N.; Sheka, E. F.; Nelson, D. K.; Starukhin, A. N.

    2014-05-01

    Viewing shungite as loosely packed fractal nets of graphene-based (reduced graphene oxide, rGO) quantum dots (GQDs), we consider photoluminescence of the latter as a convincing proof of the structural concept as well as of the GQD attribution to individual rGO fragments. We study emission from shungite GQDs for colloidal dispersions in water, carbon tetrachloride, and toluene at both room and low temperatures. As expected, the photoluminescence of the GQD aqueous dispersions is quite similar to that of synthetic GQDs of the rGO origin. The morphological study of shungite dispersions shows a steady trend of GQDs to form fractals and to drastically change the colloid fractal structure caused by the solvent exchange. Spectral study reveals a dual character of the emitting centers: individual GQDs are responsible for the spectra position while the fractal structure of GQD colloids ensures high broadening of the spectra due to structural inhomogeneity, thus causing a peculiar dependence of the photoluminescence spectra on the excitation wavelength. For the first time, photoluminescence spectra of individual GQDs were observed in frozen toluene dispersions, which paves the way for a theoretical treatment of the GQD photonics.

  5. Photoluminescence of germanium quantum dots formed by pulsed laser ablation

    International Nuclear Information System (INIS)

    Time-resolved studies of photoluminescence in the energy range 1.4-3.2 eV are carried out for GeOx films (x ≤ 2) containing Ge nanoclusters. The relaxation times vary in the range from 50 ns to 20 μs. The films are produced by single-stage pulsed laser ablation and deposited from the direct and reverse fluxes of particles of the erosion spray in oxygen and argon atmosphere. The dependences of the photoluminescence properties of the films on the conditions of deposition and on doping with gold are studied. The photoluminescence bands, with peaks at the energies 1.42-2.1 eV, are narrow, slow, and close to each other in energy, whereas the other bands, with peaks near 2.5 eV and in the range 2.7-2.9 eV, are broad, faster, and only slightly overlapping in energy. The results are interpreted in the context of the model of photoluminescence in Ge quantum dots, whose dimensions are controlled by the conditions of their formation

  6. Photoluminescence of spray pyrolysis deposited ZnO nanorods

    Directory of Open Access Journals (Sweden)

    Mikli Valdek

    2011-01-01

    Full Text Available Abstract Photoluminescence of highly structured ZnO layers comprising well-shaped hexagonal rods is presented. The ZnO rods (length 500-1,000 nm, diameter 100-300 nm were grown in air onto a preheated soda-lime glass (SGL or ITO/SGL substrate by low-cost chemical spray pyrolysis method using zinc chloride precursor solutions and growth temperatures in the range of 450-550°C. We report the effect of the variation in deposition parameters (substrate type, growth temperature, spray rate, solvent type on the photoluminescence properties of the spray-deposited ZnO nanorods. A dominant near band edge (NBE emission is observed at 300 K and at 10 K. High-resolution photoluminescence measurements at 10 K reveal fine structure of the NBE band with the dominant peaks related to the bound exciton transitions. It is found that all studied technological parameters affect the excitonic photoluminescence in ZnO nanorods. PACS: 78.55.Et, 81.15.Rs, 61.46.Km

  7. Homoeologous GSL-ELONG gene replacement for manipulation of aliphatic glucosinolates in Brassica rapa L. by marker assisted selection

    Directory of Open Access Journals (Sweden)

    Arvind H. Hirani

    2013-03-01

    Full Text Available Aliphatic glucosinolates are the predominant sulphur-rich plant secondary metabolites in economically important Brassica crops. Glucosinolates and their hydrolysis products are involved in plant-microbe, plant-insect, plant-animal and plant-human interactions. It is, therefore, important to manipulate glucosinolate profiles and contents in Brassica species. In this study, aliphatic glucosinolates were genetically manipulated through homoeologous recombination in backcross lines followed by marker assisted selection in B. rapa. A resynthesized B. napus line, from a cross between B. rapa and B. oleracea, was backcrossed with Chinese cabbage doubled haploid line, RI16. Marker assisted selection for non-functional gene was performed in each backcross generations. Advanced backcross progenies (BC3F2 were developed to identify homoeologous gene replacement and/or introgression. Reduction in 5C aliphatic glucosinolates (gluconapoleiferin, glucoalyssin and glucobrassicanapin was observed in BC3F2 progenies of the recurrent parent that carried the GSL-ELONG gene. The GSL-ELONG positive backcross progenies were also screened by the A-genome and BraGSL-ELONG gene specific marker, which linked with 5C aliphatic glucosinolates. The A-genome specific marker was absent in the plants of advanced backcross progenies which showed reduction in 5C aliphatic glucosinolates. The results suggest that the functional allele had been replaced by the non-functional GSL-ELONG allele from B. oleracea. Some advanced backcross progenies (BC3F2 positive for the GSL-ELONG allele and the A-genome specific SCAR marker BraMAM1-1 did not show reduction in 5C aliphatic glucosinolates, suggesting that GSL-ELONG allele is recessive. Replacement of the functional locus in the A genome by non-functional counterpart in the C genome reduced the content of 5C aliphatic glucosinolates in B. rapa seeds with 20 micromoles per gram.

  8. Advances in Functionalization of Biodegradable Aliphatic Polycarbonates%生物可降解脂肪族聚碳酸酯功能化研究进展

    Institute of Scientific and Technical Information of China (English)

    王庆蓉; 王华芬; 冯俊; 卓仁禧; 程巳雪

    2015-01-01

    脂肪族聚碳酸酯是一类重要的可降解高分子,在生物医用领域有着广泛的应用.聚碳酸酯的功能化可以赋予其特定的性能以满足在不同应用领域的要求.如引入特定的功能基团以调节亲疏水性、改善生物相容性、赋予其生物活性等.文中综述了近年来生物可降解脂肪族聚碳酸酯的研究进展,着重介绍了功能化脂肪族聚碳酸酯的分类、合成方法及性能.

  9. 新型含酯基的可生物降解聚碳酸酯的合成%Synthesis of Novel Biodegradable Aliphatic Polycarbonate with Ester Groups

    Institute of Scientific and Technical Information of China (English)

    程巳雪; 王浩; 汪连生; 卓仁禧

    2004-01-01

    通过2,2-二羟甲基-丙二酸二甲酯与氯甲酸乙酯的反应合成了环状碳酸酯单体5,5-二甲氧羰基-1,3-二氧六环-2-酮,再以异辛酸亚锡为催化剂,在不同温度下进行本体开环聚合,得到新型含酯基的聚碳酸酯.单体和聚合物结构经红外光谱(IR)、核磁共振氢谱(1H NMR)及核磁共振碳谱(13C NMR)表征.结果表明,开环聚合反应的产率和分子量随温度的升高而增加,但温度高于100 ℃时开环聚合会发生一定程度的脱羧反应.研究得出该聚合反应合适的反应条件为:反应温度90 ℃,反应时间12 h,聚合过程中基本无脱羧反应发生.

  10. Biodegradable polymers in clinical use and clinical development

    CERN Document Server

    Domb, Abraham J

    2011-01-01

    The definitive guide to biodegradable polymer science-where we are and what's to come The most comprehensive review of biodegradable polymers already utilized or under development for clinical use, Biodegradable Polymers in Clinical Use and Clinical Development looks at the state of biodegradable polymers now and over the next five years. Implantable molecules that break down within the body over a predetermined period of time, biodegradable polymers have been employed as drug carriers, orthopedic fixation devices, and absorbable sutures. Yet while hundreds of such polymers have been deve

  11. Fate and biodegradability of sulfonated aromatic amines

    NARCIS (Netherlands)

    Tan, N.C.G.; Leeuwen, van A.; Voorthuizen, van E.M.; Slenders, P.; Prenafeta, F.X.; Temmink, H.; Lettinga, G.; Field, J.A.

    2005-01-01

    Ten sulfonated aromatic amines were tested for their aerobic and anaerobic biodegradability and toxicity potential in a variety of environmental inocula. Of all the compounds tested, only two aminobenzenesulfonic acid (ABS) isomers, 2- and 4-ABS, were degraded. The observed degradation occurred only

  12. Natural Biodegradation of Phenolic Compounds in Groundwater

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A combination of field data and theoretical approaches is used to assess the natural attenuation and status of a complex plume of phenolic compounds (phenol, cresols, xylenols) in a deep, consolidated, UK Permo-Triassic sandstone aquifer. Biodegradation of the phenolic compounds at concentrations up to 12500mg·L-1 is occurring under aerobic, NO-3-reducing, Mn/Fe-reducing, SO2-4-reducing and methanogenic conditions in the aquifer, with the accumulation of inorganic and organic metabolites in the plume. An electron and carbon balance for the plume suggests that only 6% of the source term has been degraded in 50 years. The residual contaminant mass in the plume significantly exceeds estimates of electron acceptor inputs, indicating that the plume will grow. Two detailed vertical profiles through the plume show that contaminant distributions are controlled more by source history than by biodegradation processes. Microbiological and mass balance studies show that biodegradation is greatest at the plume fringe where contaminant concentrations are diluted by transverse mixing. Active bacterial populations exist throughout the plume but biodegradation is inhibited in the plume core by high contaminant concentrations. Stable isotope studies show that SO2-4-reduction is particularly sensitive to contaminant concentration. The aquifer is not oxidant-deficient but natural attenuation of the phenolic compounds in this system is limited by toxicity from the pollutant load and the bioavailability of electron acceptors. Natural attenuation of these contaminants will increase only after increased dilution of the plume.

  13. Phyllosphere yeasts rapidly break down biodegradable plastics.

    Science.gov (United States)

    Kitamoto, Hiroko K; Shinozaki, Yukiko; Cao, Xiao-Hong; Morita, Tomotake; Konishi, Masaaki; Tago, Kanako; Kajiwara, Hideyuki; Koitabashi, Motoo; Yoshida, Shigenobu; Watanabe, Takashi; Sameshima-Yamashita, Yuka; Nakajima-Kambe, Toshiaki; Tsushima, Seiya

    2011-01-01

    The use of biodegradable plastics can reduce the accumulation of environmentally persistent plastic wastes. The rate of degradation of biodegradable plastics depends on environmental conditions and is highly variable. Techniques for achieving more consistent degradation are needed. However, only a few microorganisms involved in the degradation process have been isolated so far from the environment. Here, we show that Pseudozyma spp. yeasts, which are common in the phyllosphere and are easily isolated from plant surfaces, displayed strong degradation activity on films made from poly-butylene succinate or poly-butylene succinate-co-adipate. Strains of P. antarctica isolated from leaves and husks of paddy rice displayed strong degradation activity on these films at 30°C. The type strain, P. antarctica JCM 10317, and Pseudozyma spp. strains from phyllosphere secreted a biodegradable plastic-degrading enzyme with a molecular mass of about 22 kDa. Reliable source of biodegradable plastic-degrading microorganisms are now in our hands. PMID:22126328

  14. Transport of nonlinearly biodegradable contaminants in aquifers

    NARCIS (Netherlands)

    Keijzer, H.

    2001-01-01

    This thesis deals with the transport behavior of nonlinearly biodegradable contaminants in aquifers. Such transport occurs during in situ bioremediation which is based on the injection of an electron acceptor or electron donor. The main interests in this thesis are the mutual influences of underlyin

  15. Biodegradable polymersomes for targeted ultrasound imaging

    NARCIS (Netherlands)

    Zhou, W.; Meng, F.; Engbers, G.H.M.; Feijen, J.

    2006-01-01

    Biodegradable polymersomes with a sub-micron size were prepared by using poly(ethylene glycol)–polylactide (PEG–PDLLA) block-copolymers in aqueous media. Air-encapsulated polymersomes could be obtained by a lyophilization/rehydration procedure. Preliminary results showed that these polymersomes were

  16. Biodegradable Polymeric Microcapsules: Preparation and Properties

    NARCIS (Netherlands)

    Sawalha, H.I.M.; Schroën, C.G.P.H.; Boom, R.M.

    2011-01-01

    Biodegradable polymeric microcapsules can be produced through different methods of which emulsion solvent-evaporation/extraction is frequently used. In this technique, the polymer (often polylactide) is dissolved in a good solvent and is emulsified together with a poor solvent into a nonsolvent phas

  17. Fabrication of Environmentally Biodegradable Lignin Nanoparticles

    NARCIS (Netherlands)

    Frangville, C.; Rutkevicius, M.; Richter, A.P.; Velev, O.D.; Stoyanov, S.D.; Paunov, V.N.

    2012-01-01

    We developed a method for the fabrication of novel biodegradable nanoparticles (NPs) from lignin which are apparently non-toxic for microalgae and yeast. We compare two alternative methods for the synthesis of lignin NPs which result in particles of very different stability upon change of pH. The fi

  18. Biodegradable synthetic polymers for tissue engineering

    Directory of Open Access Journals (Sweden)

    Gunatillake P. A.

    2003-05-01

    Full Text Available This paper reviews biodegradable synthetic polymers focusing on their potential in tissue engineering applications. The major classes of polymers are briefly discussed with regard to synthesis, properties and biodegradability, and known degradation modes and products are indicated based on studies reported in the literature. A vast majority of biodegradable polymers studied belongs to the polyester family, which includes polyglycolides and polylactides. Some disadvantages of these polymers in tissue engineering applications are their poor biocompatibility, release of acidic degradation products, poor processability and loss of mechanical properties very early during degradation. Other degradable polymers such as polyorthoesters, polyanhydrides, polyphosphazenes, and polyurethanes are also discussed and their advantages and disadvantages summarised. With advancements in tissue engineering it has become necessary to develop polymers that meet more demanding requirements. Recent work has focused on developing injectable polymer compositions based on poly (propylene fumarate and poly (anhydrides to meet these requirements in orthopaedic tissue engineering. Polyurethanes have received recent attention for development of degradable polymers because of their great potential in tailoring polymer structure to achieve mechanical properties and biodegradability to suit a variety of applications.

  19. Enhancement of 4-chlorophenol biodegradation using glucose

    Energy Technology Data Exchange (ETDEWEB)

    Tarighian, Alireza; Hill, Gordon; Headley, John [Division of Environmental Engineering, University of Saskatchewan, 105 Maintenance Road, S7N 5C5, Saskatoon, SK (Canada); Pedras, Soledad [Department of Chemistry, University of Saskatchewan, 110 Science Place, S7N 5C9, Saskatoon, SK (Canada)

    2003-03-01

    Toxic, xenobiotic chemicals present challenging problems for the environment since they are normally resistant to biodegradation. Sometimes it is possible to induce biodegradation activity by the use of growth cosubstrates. In this study, pure solutions and binary mixtures of glucose, phenol and 4-chlorophenol have been metabolized in batch cultures by a pure strain of Pseudomonas putida. Following a lag period during which slow growth and low production of biomass occurred, phenol was metabolized according to the Monod model. Glucose was also metabolized according to the Monod model but exponential growth commenced immediately after inoculation with no noticeable lag phase. Biokinetic behavior for growth on a mixture of phenol and glucose paralleled the behavior on individual substrates with simultaneous consumption of both substrates. 4-chlorophenol was not consumed as a sole substrate by Pseudomonas putida but was consumed as a cometabolite with either glucose or phenol acting as the primary growth cosubstrate. Surprisingly, glucose was found to be the superior growth cosubstrate, suggesting that inexpensive sugars can be used to enhance the biodegradation of chlorophenol-contaminated sites. Glucose and the excreted metabolic products of the biodegradation process, including a bright yellow pigment, demonstrated negligible toxicity towards Artemia salina, unlike the phenol and 4-chlorophenol substrates. (orig.)

  20. Biodegradability of leathers through anaerobic pathway.

    Science.gov (United States)

    Dhayalan, K; Fathima, N Nishad; Gnanamani, A; Rao, J Raghava; Nair, B Unni; Ramasami, T

    2007-01-01

    Leather processing generates huge amounts of both solid and liquid wastes. The management of solid wastes, especially tanned leather waste, is a challenging problem faced by tanners. Hence, studies on biodegradability of leather become imperative. In this present work, biodegradability of untanned, chrome tanned and vegetable tanned leather under anaerobic conditions has been addressed. Two different sources of anaerobes have been used for this purpose. The effect of detanning as a pretreatment method before subjecting the leather to biodegradation has also been studied. It has been found that vegetable tanned leather leads to more gas production than chrome tanned leather. Mixed anaerobic isolates when employed as an inoculum are able to degrade the soluble organics of vegetable tanned material and thus exhibit an increased level of gas production during the initial days, compared to the results of the treatments that received the anaerobic sludge. With chrome tanned materials, there was not much change in the volume of the gas produced from the two different sources. It has been found that detanning tends to improve the biodegradability of both types of leathers. PMID:16740383

  1. Biodegradable elastomeric scaffolds for soft tissue engineering

    NARCIS (Netherlands)

    Pego, Ana Paula; Poot, André A.; Grijpma, Dirk W.; Feijen, Jan

    2003-01-01

    Elastomeric copolymers of 1,3-trimethylene carbonate (TMC) and ε-caprolactone (CL) and copolymers of TMC and D,L-lactide (DLLA) have been evaluated as candidate materials for the preparation of biodegradable scaffolds for soft tissue engineering. TMC-DLLA copolymers are amorphous and degrade more r

  2. Photoluminescence of Sequential Infiltration Synthesized ZnO nanostructures

    Science.gov (United States)

    Ocola, Leonidas; Gosztola, David; Yanguas-Gil, Angel; Connolly, Aine

    We have investigated a variation of atomic layer deposition (ALD), called sequential infiltration synthesis (SiS), as an alternate method to incorporate ZnO and other oxides inside polymethylmethacrylate (PMMA) and other polymers. Energy dispersive spectroscopy (EDS) results show that we synthesize ZnO up to 300 nm inside a PMMA film. Photoluminescence data on a PMMA film shows that we achieve a factor of 400X increase in photoluminescence (PL) intensity when comparing a blank Si sample and a 270 nm thick PMMA film, where both were treated with the same 12 alternating cycles of H2O and diethyl zinc (DEZ). PMMA is a well-known ebeam resist. We can expose and develop patterns useful for photonics or sensing applications first, and then convert them afterwards into a hybrid polymer-oxide material. We show that patterning does indeed affect the photoluminescence signature of native ZnO. We demonstrate we can track the growth of the ZnO inside the PMMA polymer using both photoluminescence and Raman spectroscopy and determine the point in the process where ZnO is first photoluminescent and also at which point ZnO first exhibits long range order in the polymer. This work was supported by the Department of Energy under Contract No. DE-AC02-06CH11357. Use of the Center for Nanoscale Materials was supported by the U. S. Department of Energy, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.

  3. On aerobic biodegradability of amine collectors%胺类捕收剂的好氧生物降解性能研究

    Institute of Scientific and Technical Information of China (English)

    鄢恒珍; 龚文琪; 梅光军; 刘晓烨; 陈绍华

    2011-01-01

    , we have also studied the biodegradation mechanism of amine collectors. As the result, two potential biodegradation pathways for ether amine were found: the rupture of C-N, firstly, and then via the oxidation of wand β, to produce ultima metabolites; the other is firstly to enact the rupture of C-O, and then to produce propylamine and fatty acid which will then be oxidized. In final analysis, for primary amine to be biodegraded is to rupture C-N, firstly. Then to oxidize the products of .NH3 and aliphatic alcohol. And in the case of quaternary ammonium salt, with the rupture of C-N. it is recommended that (CH, )3N and aliphatic alcohol be produced first, and aliphatic alcohol should be degraded to final product.%为了控制胺类捕收剂对环境造成的污染,借鉴表面括性剂等有机污染物的生物降解性评价体系,采用BOD5/CODCr法和OECD-301B(IS0 9439)标准对胺类捕收剂的生物降解性进行评价,考察分子结构对生物降解度的影响.研究表明,十二胺、十八胺、癸烷基丙基醚胺(醚胺609)、十二烷基丙基醚胺(醚胺601)、十二烷基三甲基氯化铵、十二烷基三甲基溴化铵28d最终好氧生物降解率分别为76.0%、50.6% 、63.2%、56.3%、63.4%、68.0%,生物降解指数分别为173.4、162.2、160.8、149.4、164.6、171.2,其中癸烷基丙基醚胺和十二烷基丙基醚胺对微生物有抑制作用,其抑制时间分别为2d和4d,除癸烷基丙基醚胺和十二烷基丙基醚胺的BOD,/CODC值小于0.3以外,其余4种药剂的BOD5/CODCr值均在0.3以上.综合两种评价方法,这6种胺类捕收剂均属于可生物降解有机物.其生物降解性从大到小为:十二胺、十二烷基三甲基溴化铵、十二烷基三甲基氯化铵、醚胺609、十八胺、醚胺601.相对来说,有机物碳链越长,其降解性能越差,另外,碳链中醚基的加入也影响有机物的生物降解性能.最后初步探讨了胺类捕收剂的生物降解机理.

  4. Ultrastructure of Escherichia coli cells under the action of a novel derivative of aryl aliphatic aminoalcohols

    Directory of Open Access Journals (Sweden)

    Dronova M.L.

    2014-12-01

    Full Text Available Background. Novel derivatives of aryl aliphatic aminoalcohols were examined for antimicrobial activity. Compound KVM-114 (4-(1,1,3,3-tetrabutyl phenoxy-3-dimethylamino-2-propanol hydrochloride was found as a selective against gram-negative bacteria. Objective. Investigation of compound KVM-114 influence on E. coli ultrastructure. Methods. Minimum inhibitory concentrations were determined by serial dilution method in Muller-Hinton broth. Bacteria (Escherichia coli for transmission electron microscopy samples preparation was grown to exponential phase and then was exposed to the subinhibitory concentration of KVM-114 for 1 h and 24 h. Results. Intact E. coli cells were rod-shaped with rounded ends. A light layer, allowing clear visualization of the cell wall, was observed between the сytoplasm and cytoplasmic membrane. Lipopolysaccharide layer was well distinguished as well. Cytoplasm was filled with ribosomes and polyribosomes. 1 hour exposition to KVM-114 at a subinhibitory concentration resulted in the absence of polyribosomes in the cytoplasm. Increase of electron density of lipopolysaccharide layer and cell wall indicate alteration of cell envelope. Prolongation of the incubation period to 24 hours led to cell recovery: no changes were observed, compared to control cells. The data obtained suggest compound’s ability to alter cell envelope and metabolic activity, however, subinhibitory concentration is apparently not sufficient for total inhibition of E. coli growth. Conclusion. The derivative of aryl aliphatic aminoalcohols, compound KVM-114, possesses inhibitory activity against gram-negative bacteria. E. coli treatment with this compound resulted in structural changes of the cell wall and alteration of intracellular processes. Citation: Dronova ML, Voychuk SI, Vrynchanu NO. [Ultrastructure of Escherichia coli cells under the action of a novel derivative of aryl aliphatic aminoalcohols]. Morphologia. 2014;8(4:26-9. Ukrainian.

  5. Industrialization of Technology on Bio-degradable Plastics

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    @@ On August 14, 2004, aresearch project titled "Preparation of Aliphatic Ester Polycarbonate and Degradable Foam Plastics by Using Carbon Dioxide" passed its technical appraisal by experts under the sponsorship of the National Bureau of Environmental Protection.

  6. Solid state and sub-cooled liquid vapour pressures of cyclic aliphatic dicarboxylic acids

    Directory of Open Access Journals (Sweden)

    A. M. Booth

    2010-10-01

    Full Text Available Knudsen Effusion Mass Spectrometry (KEMS has been used to measure for the first time the solid state vapour pressures of a series of aliphatic cyclic dicarboxylic acids with increasing ring size. Additionally the atmospherically important compounds; cis-pinonic acid and levoglucosan were also measured. Differential Scanning Calorimetry (DSC was used to measure melting points, enthalpies and entropies of fusion, which were used to determine sub-cooled liquid vapour pressures for the compounds. The sub-cooled liquid vapour pressure of straight chain, branched and cyclic dicarboxylic acids was compared to a selection of estimation methods.

  7. Simultaneous determination of aliphatic hydrocarbons, PCBs and PCTs in pork liver by gas chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Barros, C. [Dept. de Quimica Analitica, Nutricion y Bromatologia, Area Nutricion y Bromatologia, Facultad de Farmacia, Santiago de Compostela (Spain); Alvarez Pineiro, M.E. [Inst. de Investigacion y Analisis Alimentarios, Lab. de Bromatologia, Facultad de Farmacia, Santiago de Compostela (Spain); Simal Lozano, J. [Dept. de Quimica Analitica, Nutricion y Bromatologia, Area Nutricion y Bromatologia, Facultad de Farmacia, Santiago de Compostela (Spain); Lage Yusty, M.A. [Inst. de Investigacion y Analisis Alimentarios, Lab. de Bromatologia, Facultad de Farmacia, Santiago de Compostela (Spain)

    1996-10-01

    A multicomponent extraction/concentration procedure has been developed for the enrichment of PCBs, PCTs and aliphatic hydrocarbons (pristane, C{sub 18}, C{sub 19}, C{sub 20}, C{sub 22}, C{sub 24}, C{sub 28}, C{sub 32} and C{sub 36}) in pork liver. These components of the enriched extract were then simultaneously determined by gas chromatography. Mean recoveries ranged from 81.5% for pristane to 93% for PCBs; CV % (0.9-6.7) indicated the method to be both precise and reproducible. (orig.)

  8. Using the Griess colorimetric nitrite assay for measuring aliphatic β-nitroalcohols

    OpenAIRE

    Wen, Quan; Paik, David C

    2012-01-01

    Our recent studies suggest that aliphatic β-nitroalcohols (BNAs) may represent a useful class of compounds for topical therapeutic corneoscleral cross-linking agents. Thus, this study was undertaken in order to standardize a simple method for nitroalcohol quantitation based on a denitration step followed by colorimetric Griess nitrite assay. Conditions necessary for denitration included a pH of 7-9 and heating for 1 hour at 100°C. Standard curves for two mono-nitroalcohols (2-nitroethanol and...

  9. Abilities of some higher plants to hydrolyze the acetates of phenols and aromatic-aliphatic alcohols

    Directory of Open Access Journals (Sweden)

    Agnieszka Mironowicz

    2014-02-01

    Full Text Available In the biotransformations carried out under the same conditions, the whole intact plants of Spirodela punctata, Nephrolepis exaltata, Cyrtomium falcatum, Nephrolepis cordifolia and the suspension cultures of Helianthus tuberosus, Daucus carota and Petunia hybrida hydrolyze (partially or totally the ester bonds of the acetates of phenols and aromatic-aliphatic alcohols and also the menthyl acetate. Nevertheless, the methyl esters of aromatic acids, structurally similar to the former substrates, do not undergo hydrolysis. At the same time, the viability of first four plants was observed for different levels of acetate concentration. The method of continuous preparative hydrolysis of the same acetates was worked out in Cyrtomium falcatum culture.

  10. A QSPR STUDY OF NORMAL BOILING POINT OF ORGANIC COMPOUNDS (ALIPHATIC ALKANES USING MOLECULAR DESCRIPTORS

    Directory of Open Access Journals (Sweden)

    B. Souyei

    2013-12-01

    Full Text Available A quantitative structure–property relationship (QSPR study is carried out to develop correlations that relate the molecular structures of organic compounds (Aliphatic Alkanes to their normal boiling point (NBP and two correlations were proposed for constitutionals and connectivity indices Models. The correlations are simple in application with good accuracy, which provide an easy, direct and relatively accurate way to calculate NBP. Such calculation gives us a model that gives results in remarkable correlations with the descriptors of blokes constitutionals (CON, and connectivity indices (CI (R2 = 0.950, δ = 0.766 (R2 = 0.969, δ = 0.782 respectively.

  11. Design, Synthesis and Cytotoxic Activities of Novel Aliphatic Amino-Substituted Flavonoids

    OpenAIRE

    Guannan Liu; Zhen Ge; Mengdan Zhao; Yifeng Zhou

    2013-01-01

    A series of flavonoids 9a–f, 13b, 13d, 13e and 14a–f bearing diverse aliphatic amino moieties were designed, synthesized and evaluated for their cytotoxic activities against the ECA-109, A-549, HL-60, and PC-3 cancer cell lines. Most of the compounds exhibited moderate to good activities. The structure-activity relationships were studied, revealing that the chalcone skeleton is the most preferable for cytotoxic activities. Chalcone 9d was the most promising compound due to its high potency ag...

  12. Biodegradation of acetanilide herbicides acetochlor and butachlor in soil.

    Science.gov (United States)

    Ye, Chang-ming; Wang, Xing-jun; Zheng, He-hui

    2002-10-01

    The biodegradation of two acetanilide herbicides, acetochlor and butachlor in soil after other environmental organic matter addition were measured during 35 days laboratory incubations. The herbicides were applied to soil alone, soil-SDBS (sodium dodecylbenzene sulfonate) mixtures and soil-HA (humic acid) mixtures. Herbicide biodegradation kinetics were compared in the different treatment. Biodegradation products of herbicides in soil alone samples were identified by GC/MS at the end of incubation. Addition of SDBS and HA to soil decreased acetochlor biodegradation, but increased butachlor biodegradation. The biodegradation half-life of acetochlor and butachlor in soil alone, soil-SDBS mixtures and soil-HA mixtures were 4.6 d, 6.1 d and 5.4 d and 5.3 d, 4.9 d and 5.3 d respectively. The biodegradation products were hydroxyacetochlor and 2-methyl-6-ethylaniline for acetochlor, and hydroxybutachlor and 2,6-diethylaniline for butachlor.

  13. Development of biodegradable materials; balancing degradability and performance

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, J.M.; Allen, A.L.; Dell, P.A.; McCassie, J.E.; Shupe, A.E.; Stenhouse, P.J. Stenhouse, Welch, E.A.; Kaplan, D.L. [Army Natick Research Development, MA (United States)

    1993-12-31

    The development of biodegradable materials suitable for packaging must take into consideration various performance criteria such as mechanical and barrier properties, as well as rate of biodegradability in given environments. Individual or blended biopolymer films were obtained commercially or blown into film in the laboratory and tested for tensile strength, ultimate elongation and oxygen barrier. These films were then subjected to accelerated marine biodegradation tests as well as simulated marine respirometry. Starch/ethylene vinyl alcohol films exhibited good mechanical and excellent oxygen barrier properties, but were very slow to biodegrade in the simulated and excellent oxygen barrier properties, but were very slow to biodegrade in the simulated marine environment. Polyhydroxyalkanoates had good mechanical properties, average oxygen barrier and good biodegradability. Data indicate that performance and biodegradability of packaging can be tailored to needs by combining individual biopolymers in different proportions in blends and laminates.

  14. Improving the biodegradative capacity of subsurface bacteria

    International Nuclear Information System (INIS)

    The continual release of large volumes of synthetic materials into the environment by agricultural and industrial sources over the last few decades has resulted in pollution of the subsurface environment. Cleanup has been difficult because of the relative inaccessibility of the contaminants caused by their wide dispersal in the deep subsurface, often at low concentrations and in large volumes. As a possible solution for these problems, interest in the introduction of biodegradative bacteria for in situ remediation of these sites has increased greatly in recent years (Timmis et al. 1988). Selection of biodegradative microbes to apply in such cleanup is limited to those strains that can survive among the native bacterial and predator community members at the particular pH, temperature, and moisture status of the site (Alexander, 1984). The use of microorganisms isolated from subsurface environments would be advantageous because the organisms are already adapted to the subsurface conditions. The options are further narrowed to strains that are able to degrade the contaminant rapidly, even in the presence of highly recalcitrant anthropogenic waste mixtures, and in conditions that do not require addition of further toxic compounds for the expression of the biodegradative capacity (Sayler et al. 1990). These obstacles can be overcome by placing the genes of well-characterized biodegradative enzymes under the control of promoters that can be regulated by inexpensive and nontoxic external factors and then moving the new genetic constructs into diverse groups of subsurface microbes. ne objective of this research is to test this hypothesis by comparing expression of two different toluene biodegradative enzymatic pathways from two different regulatable promoters in a variety of subsurface isolates

  15. Hydrocarbons biodegradation in unsaturated porous medium

    International Nuclear Information System (INIS)

    Biological processes are expected to play an important role in the degradation of petroleum hydrocarbons in contaminated soils. However, factors influencing the kinetics of biodegradation are still not well known, especially in the unsaturated zone. To address these biodegradation questions in the unsaturated zone an innovative experimental set up based on a physical column model was developed. This experimental set up appeared to be an excellent tool for elaboration of a structured porous medium, with well defined porous network and adjusted water/oil saturations. Homogeneous repartition of both liquid phases (i.e., aqueous and non aqueous) in the soil pores, which also contain air, was achieved using ceramic membranes placed at the bottom of the soil column. Reproducible interfaces (and connectivity) are developed between gas, and both non mobile water and NAPL phases, depending on the above-defined characteristics of the porous media and on the partial saturations of these three phases (NAPL, water and gas). A respirometric apparatus was coupled to the column. Such experimental set up have been validated with hexadecane in dilution in an HMN phase. This approach allowed detailed information concerning n-hexadecane biodegradation, in aerobic condition, through the profile of the oxygen consumption rate. We have taken benefit of this technique, varying experimental conditions, to determine the main parameters influencing the biodegradation kinetics and compositional evolution of hydrocarbons, under steady state unsaturated conditions and with respect to aerobic metabolism. Impacts of the nitrogen quantity and of three different grain sizes have been examined. Biodegradation of petroleum cut, as diesel cut and middle distillate without aromatic fraction, were, also studied. (author)

  16. Biodegradable poly lactone-family polymer and their applications in medical field

    International Nuclear Information System (INIS)

    Poly lactone-family polymers such as poly lactide, poly glycolide and polycaprolactone are kind aliphatic polyester. Since they can degrade by hydrolysis reaction under all the ph condition and possess biocompatibility, biodegradability and other good properties, especially they included not peptide bond in their molecules, they are non-antigen and non-immunization, as well as have no-toxicity and no-stimulation. So they are interested biomaterials and very useful in medical field. However the properties of all of the homo-poly lactones can not be changed in a large range, the limited properties result in limited applications of these homo-poly lactones. Based on macromolecular design, a series of copolylactones such as poly(lactide-co-glycolide) (PLGA), poly(glycolide-co-lactide-co-caprolactone) tri- component copolymer (PGLC), tri- and multi-block poly lactide/poly(ethylene oxide) copolymer (TPLE and BPLE), as well as polycaprolactone/poly lactide/poly(ethylene oxide) copolymer (PCEL) et al were synthesized by copolymerization among various lactone monomers or lactone monomers with poly(ethylene glycol). These copolylactones have wide range of degradation life from several months to years and different mechanical properties. After plasma treatment the surface property of the copolylactones were improved further and cell affinity of the copolylactones was improved obviously. The applications of these poly lactone-family polymers in medical field for used as drug carrier in drug delivery system, and as cell scaffold in tissue engineering were discussed

  17. Surface modifications of photocrosslinked biodegradable elastomers and their influence on smooth muscle cell adhesion and proliferation.

    Science.gov (United States)

    Ilagan, Bernadette G; Amsden, Brian G

    2009-09-01

    Photocrosslinked, biodegradable elastomers based on aliphatic polyesters have many desirable features as scaffolds for smooth muscle tissue engineering. However, they lack cell adhesion motifs. To address this shortcoming, two different modification procedures were studied utilizing a high and a low crosslink density elastomer: base etching and the incorporation of acryloyl-poly(ethylene glycol) (PEG)-Gly-Arg-Gly-Asp-Ser (GRGDS) into the elastomer network during photocrosslinking. Base etching improved surface hydrophilicity without altering surface topography, but did not improve bovine aortic smooth muscle cell adhesion. Incorporation of PEG-GRGDS into the elastomer network significantly improved cell adhesion for both high and low crosslink density elastomers, with a greater effect with the higher crosslink density elastomer. Incorporation of GRGDS into the high crosslink density elastomer also enhanced smooth muscle cell proliferation, while proliferation on the low crosslink density unmodified, base etched, and PEG-GRGDS incorporated elastomers was significantly greater than on the high crosslink density unmodified and base etched elastomer. PMID:19375999

  18. The C--H Stretching Features at 3.2--3.5 Micrometer of Polycyclic Aromatic Hydrocarbons with Aliphatic Sidegroups

    CERN Document Server

    Yang, Xuejuan; Glaser, Rainer; Zhong, Jianxin

    2016-01-01

    The so-called unidentified infrared emission (UIE) features at 3.3, 6.2, 7.7, 8.6, and 11.3 micrometer are ubiquitously seen in a wide variety of astrophysical regions. The UIE features are characteristic of the stretching and bending vibrations of aromatic hydrocarbon materials, e.g., polycyclic aromatic hydrocarbon (PAH) molecules. The 3.3 micrometer aromatic C--H stretching feature is often accompanied by a weaker feature at 3.4 micrometer. The latter is often thought to result from the C--H stretch of aliphatic groups attached to the aromatic systems. The ratio of the observed intensity of the 3.3 micrometer aromatic C--H feature to that of the 3.4 micrometer aliphatic C--H feature allows one to estimate the aliphatic fraction of the UIE carriers, provided that the intrinsic oscillator strengths of the 3.3 micrometer aromatic C--H stretch (A3.3) and the 3.4 micrometer aliphatic C--H stretch (A3.4) are known. While previous studies on the aliphatic fraction of the UIE carriers were mostly based on the A3.4...

  19. Aliphatic and polycyclic aromatic hydrocarbons in sediments of the Slovenian coastal area (Gulf of Trieste, northern Adriatic).

    Science.gov (United States)

    Bajt, Oliver

    2012-12-01

    The distribution and sources of aliphatic and polycyclic aromatic hydrocarbons (PAH) were determined in sediments at seven sites around the Slovenian coastal area. The potential toxicological significance was also assessed using biological thresholds. The results of the analyses showed higher concentrations of hydrocarbons in the Port of Koper and in the Marina of Portoroz. The influence of pollution was also evident in rather higher concentrations of hydrocarbons in the surrounding area in the Bays of Koper and Piran. Concentrations of hydrocarbons decrease toward the central part of the Gulf of Trieste. The major component of the aliphatic fraction was the unresolved complex mixture. Concentrations of the total resolved aliphatic hydrocarbons were in a range from 689 to 3,164 ng g(-1). Concentrations of the total PAHs were between 330 and 1,173 ng g(-1). Polycyclic aromatic hydrocarbons are primarily of pyrolytic origin with some smaller contributions of the petrogenic, while the aliphatic are mostly of petrogenic origin with significant amounts of biogenic derived compounds of terrestrial and marine origin. Strong evidence of the diagenetic origin of perylene in the investigated area was also found. Quite a good linear relationship between PAH concentration and TOC and between aliphatic hydrocarbon concentrations and TOC was observed. The principal component analysis showed differences between the nearshore and offshore sites. In general, the investigated area is moderately contaminated by hydrocarbons. Concentrations of PAHs, hydrocarbons of high concern, are below the levels (effects range low and the effects range median) associated with adverse biological effects. PMID:22270593

  20. Halides with Fifteen Aliphatic C–H···Anion Interaction Sites

    Science.gov (United States)

    Shi, Genggongwo; Aliakbar Tehrani, Zahra; Kim, Dongwook; Cho, Woo Jong; Youn, Il-Seung; Lee, Han Myoung; Yousuf, Muhammad; Ahmed, Nisar; Shirinfar, Bahareh; Teator, Aaron J.; Lastovickova, Dominika N.; Rasheed, Lubna; Lah, Myoung Soo; Bielawski, Christopher W.; Kim, Kwang S.

    2016-07-01

    Since the aliphatic C–H···anion interaction is relatively weak, anion binding using hydrophobic aliphatic C–H (Cali–H) groups has generally been considered not possible without the presence of additional binding sites that contain stronger interactions to the anion. Herein, we report X-ray structures of organic crystals that feature a chloride anion bound exclusively by hydrophobic Cali–H groups. An X-ray structure of imidazolium-based scaffolds using Cali–H···A‑ interactions (A‑ = anion) shows that a halide anion is directly interacting with fifteen Cali–H groups (involving eleven hydrogen bonds, two bidentate hydrogen-bond-type binding interactions and two weakly hydrogen-bonding-like binding interactions). Additional supporting interactions and/or other binding sites are not observed. We note that such types of complexes may not be rare since such high numbers of binding sites for an anion are also found in analogous tetraalkylammonium complexes. The Cali–H···A‑ interactions are driven by the formation of a near-spherical dipole layer shell structure around the anion. The alternating layers of electrostatic charge around the anion arise because the repulsions between weakly positively charged H atoms are reduced by the presence of the weakly negatively charged C atoms connected to H atoms.

  1. Halides with Fifteen Aliphatic C-H···Anion Interaction Sites.

    Science.gov (United States)

    Shi, Genggongwo; Aliakbar Tehrani, Zahra; Kim, Dongwook; Cho, Woo Jong; Youn, Il-Seung; Lee, Han Myoung; Yousuf, Muhammad; Ahmed, Nisar; Shirinfar, Bahareh; Teator, Aaron J; Lastovickova, Dominika N; Rasheed, Lubna; Lah, Myoung Soo; Bielawski, Christopher W; Kim, Kwang S

    2016-01-01

    Since the aliphatic C-H···anion interaction is relatively weak, anion binding using hydrophobic aliphatic C-H (Cali-H) groups has generally been considered not possible without the presence of additional binding sites that contain stronger interactions to the anion. Herein, we report X-ray structures of organic crystals that feature a chloride anion bound exclusively by hydrophobic Cali-H groups. An X-ray structure of imidazolium-based scaffolds using Cali-H···A(-) interactions (A(-) = anion) shows that a halide anion is directly interacting with fifteen Cali-H groups (involving eleven hydrogen bonds, two bidentate hydrogen-bond-type binding interactions and two weakly hydrogen-bonding-like binding interactions). Additional supporting interactions and/or other binding sites are not observed. We note that such types of complexes may not be rare since such high numbers of binding sites for an anion are also found in analogous tetraalkylammonium complexes. The Cali-H···A(-) interactions are driven by the formation of a near-spherical dipole layer shell structure around the anion. The alternating layers of electrostatic charge around the anion arise because the repulsions between weakly positively charged H atoms are reduced by the presence of the weakly negatively charged C atoms connected to H atoms. PMID:27444513

  2. Using of mass spectrum for prognosis of melting temperature of monatomic aliphatic spirits

    International Nuclear Information System (INIS)

    In present article researching possibility of prediction of melting temperature (MT) of monatomic aliphatic spirits with using mass-spectra as descriptors structure of molecules. Mass-spectra of 84 aliphatic spirits were used. Mass-spectra were preliminarily transformed on special formula before calculations for receiving work dates of descriptors. Calculations fulfilled with help of the computer program PROGROC. Quality of prediction characterized by coefficient of R-correlation between predicted and experimental dates MT and standard s-deviation. Coefficient of R-correlation between experimental and calculated dates account for 0.9785, standard s-deviation = 11.25 deg. C. Singly R and S for training and control excerpt equally 0.9789 and 11.31 deg. C, 0,9789 and 8.87 deg. C accordingly. Advantage of workable by us method lie in that, what on comparable with literature data of accuracy for prediction property is enough to have only mass-spectrum of substance

  3. Aliphatic and aromatic hydrocarbons in particulate fallout of Alexandria, Egypt: Sources and implications

    Energy Technology Data Exchange (ETDEWEB)

    Aboul-Kassim, T.A.T.; Simoneit, B.R.T. [Oregon State Univ., Corvallis, OR (United States)

    1995-10-01

    Particulate fallout samples (PFS) were collected in Alexandria, and their aliphatic and aromatic hydrocarbon compositions were determined both quantitatively and qualitatively to characterize the homologous and biomarker compounds in terms of their original sources. The results show that all samples contain aliphatic hydrocarbons, including n-alkanes, UCM, isoprenoids, tri- and tetracyclic terpanes, hopanes, and steranes/diasteranes. The main source of these compounds is from petrochemical contamination with trace input of terrestrial higher plant wax. In addition, polycyclic aromatic hydrocarbons, which are considered to be combustion products from fossil fuels such as petroleum, are also widely distributed in all samples. Multivariate statistical analysis, including extended Q-mode factor analysis and linear programming technique, was performed in order to reduce the hydrocarbon data set into a meaningful number of end members (sources). This analysis indicates that there are two significant end members explaining 90% of the total variation among the samples and confirming petrochemical (79.6%), and thermogenic/pyrolytic (10.4%) sources in the PFS model. 65 refs., 7 figs., 4 tabs.

  4. Branched aliphatic alkanes of shell bar section in Qarhan Lake, Qaidam Basin and their paleoclimate significance

    Institute of Scientific and Technical Information of China (English)

    ZHANG HuCai; CHANG FengQin; LI Bin; LEI GuoLiang; CHEN Yue; ZHANG WenXiang; NIU Jie; FAN HongFang; YANG MingSheng

    2007-01-01

    Biomarkers of paleolake deposits from Qarhan Salt Lake in Qaidam Basin, northwest China were systematically analyzed and the A-C series compounds of branched aliphatic alkanes with quaternary substituted carbon atom (BAQCs) were identified. The homologous distinguished three series, A-C,were identified as 5,5-diethylalkanes, 6,6-diethylalkanes and 5-butyl, 5-ethylalkanes series, and their relative abundance was A > B > C. Series A and C were characterized by odd carbon numbers, whereas series B was characterized by even carbon numbers. The high values of series A corresponded with the high values of series B and C. Therefore, it can be concluded that series A, B and C possess a similar biological origin. The abundance of series A was relatively Iow in the lower part of the section compared with that in the upper part, implying that these series originated from bacteria and/or algae more prevalent in fresh-mesohaline water, and such kinds of bacteria and/or algae are most likely to be thermophilous species. The A25/nC25 ratio differences in the section show that such branched aliphatic alkanes can be treated as one kind of environmental change proxy for paleolake evolution and may provide important information for the climate reconstruction of the Late Pleistocene.

  5. Decomposition mechanisms of trinitroalkyl compounds: a theoretical study from aliphatic to aromatic nitro compounds.

    Science.gov (United States)

    Fayet, Guillaume; Rotureau, Patricia; Minisini, Benoit

    2014-04-14

    The chemical mechanisms involved in the decomposition of trinitroethyl compounds were studied for both aliphatic and aromatic derivatives using density functional theory calculations. At first, in the case of 1,1,1-trinitrobutane, used as a reference molecule, two primary channels were highlighted among the five investigated ones: the breaking of the C-N bond and the HONO elimination. Then, the influence of various structural parameters was studied for these two reactions by changing the length of the carbon chain, adding substituents or double bonds along the carbon chain. If some slight changes in activation energies were observed for most of these features, no modification of the competition between the two investigated reactions was highlighted and the breaking of the C-N bond remained the favoured mechanism. At last, the reactions involving the trinitroalkyl fragments were highlighted to be more competitive than reactions involving nitro groups linked to aromatic cycles in two aromatic systems (4-(1,1,1-trinitrobutyl)-nitrobenzene and 2-(1,1,1-trinitrobutyl)-nitrobenzene). This showed that aromatic nitro compounds with trinitroalkyl derivatives decompose from their alkyl part and may be considered more likely as aliphatic than as aromatic regarding the initiation of their decomposition process.

  6. Aliphatic esters as targets of esterase activity in the parsnip webworm (Depressaria pastinacella).

    Science.gov (United States)

    Zangerl, Arthur R; Liao, Ling-Hsiu; Jogesh, Tania; Berenbaum, May R

    2012-02-01

    As a specialist on the reproductive structures of Pastinaca sativa and species in the related genus Heracleum, the parsnip webworm (Depressaria pastinacella) routinely encounters a distinctive suite of phytochemicals in hostplant tissues. Little is known, however, about the detoxification mechanisms upon which this species relies to metabolize these compounds. In this study, larval guts containing hostplant tissues were homogenized, and metabolism was determined by incubating reactions with and without NADPH and analyzing for substrate disappearance and product appearance by gas chromatography-mass spectrometry. Using this approach, we found indications of carboxylesterase activity, in the form of appropriate alcohol metabolites for three aliphatic esters in hostplant tissues-octyl acetate, octyl butyrate, and hexyl butyrate. Involvement of webworm esterases in hostplant detoxification subsequently was confirmed with metabolism assays with pure compounds. This study is the first to implicate esterases in lepidopteran larval midgut metabolism of aliphatic esters, ubiquitous constituents of flowers and fruits. In addition, this method confirmed that webworms detoxify furanocoumarins and myristicin in their hostplants via cytochrome P450-mediated metabolism, and demonstrated that these enzymes also metabolize the coumarin osthol and the fatty acid derivative palmitolactone. PMID:22350520

  7. Extraction and solubility characteristics of metal aliphatic carboxylates in a hexane medium

    International Nuclear Information System (INIS)

    Extractions of 30 metal ions with aliphatic carboxylic acids into hexane were carried out to understand their extraction behavior. Results were expressed in an area-graph form for metal partitions among the three (aqueous, organic and/or solid) phases in the range pH 1-9. The difference in half-extraction pH (pH1/2) between various metals can be explained by the electrostatic effect (hard acids) and the polarizability. According to the solubility of the metal complexes into organic phase, the thirty metal ions were divided into two groups. The metal ions with high ionic potential (group A) were generally extractable by every carboxylic acid tested. The large size metal ions (group B) precipitated at the liquid/liquid interface by n-aliphatic carboxylic acids and were perfectly extracted by 2-ethylhexanoic acid. We propose that this difference in the group B is caused by interface-coagulation through inter-molecular hydrophobic bond formation in the former, while the branched chain in the carboxylic acid weakens the interaction in the latter. For group A, therefore, most of the extracted species would be origomers so that no coagulation would occur. (author)

  8. New aliphatic glycerophosphoryl-containing polyurethanes: synthesis, platelet adhesion and elution cytotoxicity studies.

    Science.gov (United States)

    Acetti, Daniela; D'Arrigo, Paola; Giordano, Carmen; Macchi, Piero; Servi, Stefano; Tessaro, Davide

    2009-04-01

    in this study new poly(ether)urethanes (PeUs) based on aliphatic diisocyanates were synthesized with phospholipid-like residues as chain extenders. The primary objective was to prepare new polyurethanes from diisocyanates that are less toxic than the aromatic ones widely used in medical-grade polyurethanes, in order to investigate the effect of the different aromatic or aliphatic hard segment content on the final properties of the materials. Some glycerophospho residues were simultaneously introduced to enhance the hemocompatibility of these materials. Polymers were prepared by a conventional two-step solution polymerization procedure using hexamethylene diisocyanate (HDi) and dodecametilendiisocyanate (DDi) and poly(1,4-butanediol) with molecular weight 1000 to form prepolymers, which were subsequently polymerized with 1-glycerophosphorylcholine (1-GPC) or glycerophosphorylserine (GPS) to act as chain extenders. The reference polymers bearing 1,4-butandiol (BD) were also synthesized. The polymers obtained were characterized by fourier transform infrared spectroscopy (fT-iR), nuclear magnetic resonance (1H nmR), and differential scanning calorimetry (DSC). The hemocompatibility of synthesized segmented polyurethanes was preliminarily investigated by platelet-rich plasma contact studies and related scanning electron microscopy (Sem) photographs as well as by cell viability assay after cell exposure to material elutions to assess the effect of any toxic leachables coming out from the samples. Two of the polymers gave interesting results, suggesting the desirability of further investigation into their possible use in biomedical devices. PMID:19569028

  9. Hyperbranched Aliphatic Polyester Modified Activated Carbon Particles with Homogenized Surface Groups

    Science.gov (United States)

    Liu, Peng; Zhang, Liuxue

    The hyperbranched aliphatic polyester grafted activated carbon (HAPE-AC), was successfully prepared by the simple "one-pot" method. The surface functional groups of commercial activated carbon particles were homogenized to hydroxyl groups by being oxidized with nitric acid and then reduced with lithium tetrahydroaluminate (LiAlH4) at first. Secondly, the surface hydroxyl groups were used as the active sites for the solution polycondensation of the AB2 monomer, 2, 2-bis(hydroxymethyl)propionic acid (bis-MPA), with the catalysis of p-toluenesulfonic acid (p-TSA). The homogenization of the surface groups of the activated carbon particles and the graft polymerization of the hyperbranched aliphatic polyester were investigated by X-ray photoelectron spectroscopy (XPS) technique. The products were also characterized with Fourier transform infrared (FT-IR) and scanning electron microscope (SEM). The competitive adsorption properties of the products toward the heavy metal ions (Cu(II), Hg(II), Zn(II), and Cd(II)) also proved the translations of the surface groups.

  10. Phase diagrams in blends of poly(3-hydroxybutyric acid with various aliphatic polyesters

    Directory of Open Access Journals (Sweden)

    2011-07-01

    Full Text Available Phase behavior with immiscibility, miscibility, crystalline morphology, and kinetic analysis in blends of poly(3-hydroxybutyric acid (PHB with aliphatic polyesters such as poly(butylene adipate (PBA, poly(ethylene adipate (PEA, poly(trimethylene adipate (PTA, or poly(ethylene succinate (PESu, respectively, were explored mainly using differential scanning calorimeter (DSC and polarized-light optical microscopy (POM. Immiscibility phase behavior with reversible upper-critical-solution-temperature (UCST is common in the PHB/polyester blends. The polyester/polyester blend of PHB/PTA is partially miscible with no UCST in melt and amorphous glassy states within a composition range of PTA less than 50 wt%. The miscible crystalline/crystalline blend exhibits ring-banded spherulites at Tc = 50~100°C, with inter-ring spacing dependent on Tc. All immiscible or partially miscible PHB/polyester blends, by contrast, exhibit disrupted ringbanded spherulites or discrete spherical phase domains upon cooling from UCST to crystallization. The blends of PHB with all other aliphatic polyesters, such as PESu, PEA, PBA, etc. are only partially miscible or immiscible with an upper critical solution temperature (UCST at 180~221°C depending on blend composition. UCST with reversibility was verified.

  11. Structure-property relationship in aliphatic polyamide/polyaniline surface layered composites

    Energy Technology Data Exchange (ETDEWEB)

    Fatyeyeva, K., E-mail: kateryna.fatyeyeva@univ-rouen.fr [Institute of Bioorganic Chemistry and Petrochemistry of National Academy of Science of Ukraine, 50 Kharkivske shose, Kyiv 02160 (Ukraine); Laboratoire de Physique de l' Etat Condense, UMR CNRS 6087, Universite du Maine, Av. Olivier Messiaen, 72085 Le Mans cedex 9 (France); Laboratoire Polymeres, Biopolymeres et Surfaces, UMR 6270 and FR 3038 CNRS, Universite de Rouen, Bd. Maurice de Broglie, 76821 Mont Saint Aignan cedex (France); Pud, A.A. [Institute of Bioorganic Chemistry and Petrochemistry of National Academy of Science of Ukraine, 50 Kharkivske shose, Kyiv 02160 (Ukraine); Bardeau, J.-F.; Tabellout, M. [Laboratoire de Physique de l' Etat Condense, UMR CNRS 6087, Universite du Maine, Av. Olivier Messiaen, 72085 Le Mans cedex 9 (France)

    2011-10-17

    Highlights: {yields} Synthesis of surface conducting polymers based on aliphatic polyamides and polyaniline. {yields} The study revealed the layered structure of the surface conductive composites. {yields} Different dielectric relaxation processes were found as a function of doping agent and polyaniline oxidation state. {yields} Conductivity value (10{sup -4}-10{sup -11} S cm{sup -1}) enables the use of such composites as antistatic/electrostatic discharge materials. - Abstract: Conducting polymer composite films based on different aliphatic polyamides (PA) (PA-6, PA-11 and PA-12) have been synthesized by in situ aniline polymerization inside a surface layer of the PA host matrix. Dielectric permittivity and dielectric loss of these films are explained in terms of the interfacial polarization. The real part of permittivity is found to be higher in the PA/polyaniline (PANI) composite films than in the virgin PA polymer matrix. Such behaviour is attributed to the interaction between PA and PANI molecular chains and to the conductivity increase after the aniline polymerization. The performed confocal Raman spectrometry and X-ray diffraction studies also confirmed the presence of interactions between PA and PANI molecular chains.

  12. Anaerobic biotransformation of chlorinated aliphatic hydrocarbons: Ugly duckling to beautiful swan

    Energy Technology Data Exchange (ETDEWEB)

    Parkin, G.F.

    1999-10-01

    For many years anaerobic biological processes were reputed to be more sensitive than aerobic processes to toxic substances such as chlorinated aliphatic hydrocarbons (CAH) and thus a poor choice for treating water containing these compounds. This was especially true for water containing perchloroethylene (PCE) or trichloroethylene (TCE) because vinyl chloride, a human carcinogen, is produced when these two compounds are degraded anaerobically. Aerobic treatment with organisms containing oxygenase enzyme systems, which could fortuitously degrade a wide variety of chlorinated aliphatics (but not PCE), was favored. Recently, however, several enrichments and organisms have been isolated that will convert PCE and TCE into ethene and ethane, as shown by field data. Because of this evidence, anaerobic processes are now considered a significant alternative treatment for CAH contamination. Recent work at the University of Iowa, Iowa City, has focused on the effect of mixtures of CAHs on biotransformation of individual organic compounds and the potential for a combined methanogen-iron (Fe(0)) system to improve CAH bioremediation. At the concentration ranges tested, the presence of a mixture of CAHs seems to decrease rate of transformation of individual organics. However, there are important exceptions; in some cases a mixture of CAHs seems to facilitate transformation of an individual organic compound. Combination of an active methanogenic population with Fe(0) increases the rate and extent of transformation of carbon tetrachloride and chloroform. Results with PCE and 1,1,1-trichloroethane are less clear.

  13. Determination of aliphatic aldehydes by liquid chromatography with pulsed amperometric detection.

    Science.gov (United States)

    Casella, Innocenzo G; Contursi, Michela

    2005-01-21

    An electrochemical detection method for short-chain saturated and unsaturated aliphatic aldehydes separated by liquid chromatography in moderately acidic medium is described. A triple-step waveform of the potentials applied to the polycrystalline platinum electrode, is proposed for sensitive detection of aliphatic aldehydes in flowing streams avoiding tedious pre- or post-column derivatization and/or cleanup procedures. The influences of the perchloric acid concentration and dissolved oxygen in the mobile phase, on the amperometric and chromatographic performance were evaluated and considered in terms of sensitivity and selectivity. Under the optimised experimental conditions (i.e., deoxygenated 50mM HClO4) the proposed analytical method allowed detection limits between 0.2 microM for acrolein and 2.5 microM for valeraldehyde. Regression analysis of calibration data indicates that responses for all investigated compounds are linear over about 2 orders of magnitude above the LOD, with correlation coefficients >0.990. The method was successfully applied to the determination of formaldehyde, acetaldehyde, propionaldehyde and acrolein in real matrices such as spiked water and red wines with good mean recoveries (81-97%). PMID:15700464

  14. Photoluminescence of silicone oil treated by fluorocarbon plasma

    Institute of Scientific and Technical Information of China (English)

    Chen Tian; Ye Chao; Yuan Ying; Deng Yan-Hong; Ge Shui-Bin; Xu Yi-Jun; Ning Zhao-Yuan; Pan Xiao-Ping; Wang Zhen-Ming

    2012-01-01

    We investigated photoluminescence characteristics of silicone oils treated by C2F6 and CHF3 plasma.The silicone oil treated by the C2F6 plasma emitted a white light mainly composed of 415 nm,469 nm,and 554 nm emissions,while that treated by the CHF3 plasma emitted a pink light (415 nm).Fourier transformed infrared spectroscopy and Raman spectroscopy studies showed that the photoluminescence was correlated with the Si-C bond,the carbon-related defects and the oxygen vacancies.It was suggested that the light emitting at 554 nm was related to the Si-C bond and the carbon-related defects,while the pink emission at 415 nm was related to the oxygen vacancies.

  15. The Photoluminescence Spectra of the Aeschynite Group Minerals

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Raman and photoluminescence spectra of the metamict and annealing recrystallization titanoaeschynite-(Nd) and nioboaeschynite-(Ce), found in Baiyunobo mineral deposit in China, were measured and discussed. The peaks or bands in the spectra of the metamic minerals are weak, broad and diffuse, but sharpen notably after heating. The results show that the distortion of the structure and disorder state of the elements exists in the minerals when natural crystalline minerals transformed into metamict minerals after a long period of self-irradiation structure damaging. And all bands in the photoluminescence spectra of the aeschynite group mineral stem from emission transitions of Nd3+, when 514.5nm laser is used as the excitation source.

  16. Preparation and Photoluminescence of ZnO Nanostructures

    Institute of Scientific and Technical Information of China (English)

    YAN Jin-Liang; ZHAO Yin-nu; SUN Xue-qing; GUO Chun

    2006-01-01

    Porous anodic alumina (PAA) hosts with ZnO nanoparticles loaded in were prepared by immersing PAA films in an aqueous solution of zinc acetate and then annealing at high temperatures. Highly ordered ZnO nanodot arrays were produced using the method in combination of PAA template with RF magnetron sputtering deposition. The photoluminescence of the ZnO/PAA composite and the highly ordered ZnO nanodot arrays were investigated by means of a fluorescent spectrometer. The ZnO/PAA composite exhibits intense and broad photoluminescence spectra with the peak position at around 485 nm. The ZnO nanodot arrays have a strong UV light emissive peak at about 380 nm and a wide light emissive peak at 460 nm-610 nm at the room temperature.

  17. Spatially resolved micro-photoluminescence imaging of porphyrin single crystals

    Science.gov (United States)

    Marin, Dawn M.; Castaneda, Jose; Kaushal, Meesha; Kaouk, Ghallia; Jones, Daniel S.; Walter, Michael G.

    2016-08-01

    We describe the collection of both time-resolved and steady-state micro-photoluminescence data from solution-grown single crystals of 5,15-bis(4-carbomethoxyphenyl)porphyrin (BCM2PP). Linking molecular orientation and structure with excited-state dynamics is crucial for engineering efficient organic solar cells, light-emitting diodes, and related molecular electronics. Photoluminescence features of single porphyrin crystals were imaged using a laser scanning confocal microscope equipped with time-correlated single photon counting (TCSPC). We show enhanced exciton lifetimes (τs1 = 2.6 ns) and stronger steady-state emission in crystalline BCM2PP samples relative to semicrystalline thin films (τs1 = 1.8 ns).

  18. Intensity dependent photoluminescence studies on zinc oxide nanowires

    Science.gov (United States)

    Tzolov, Marian; Epps, Andrew; Driscoll, Eric; Barcikowski, Zachary

    2012-02-01

    The ZnO nanowires were grown by the chemical vapor transport method using a thin gold film as a catalyst. Their light emission in the visible and near UV spectral range was studied using excitation sources with large variation of the pump intensity, e.g. Xenon lamp, UV LEDs, nitrogen laser. The photoluminescence spectrum consists typically of the exciton emission band and a defect related band in the green spectral range. We have observed drastic change in the photoluminescence spectrum at high pump intensities with drastically decreased intensity of the defect related band. The results have been interpreted within a model accounting for the surface effects and associated band banding at the surface. Cathodoluminescence measurements of ZnO nanowires and bulk films were performed, which support the proposed model.

  19. Modulation of mixed-phase titania photoluminescence by oxygen adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Pallotti, D.; Orabona, E.; Amoruso, S.; Maddalena, P. [Dipartimento di Fisica, Universitá degli Studi di Napoli “Federico II,” Via Cintia, I-80126 Napoli (Italy); Institute for Superconductors, Oxides and Innovative Materials and Devices, CNR-SPIN, U.O.S. Napoli, Via Cintia, I-80126 Napoli (Italy); Lettieri, S., E-mail: stefano.lettieri@spin.cnr.it [Institute for Superconductors, Oxides and Innovative Materials and Devices, CNR-SPIN, U.O.S. Napoli, Via Cintia, I-80126 Napoli (Italy)

    2014-07-21

    We investigate the effect of oxygen (O{sub 2}) adsorption on photoluminescence properties of mixed-phase titania nanoparticle films deposited by femtosecond pulsed laser deposition, aiming to assess preliminary conclusions about the feasibility of opto-chemical sensing based on titania. We evidence that O{sub 2} produces opposite responses in rutile and anatase photoluminescence efficiency, highlighting interesting potentialities for future double-parametric optical sensing based on titania. The results evidence an important role of lattice oxygen atoms, suggesting that the standard Schottky barrier mechanism driving the response toward gas species in most used metal-oxide sensors (e.g., tin dioxide) is not the only active mechanism in titania.

  20. Radioluminescence and photoluminescence of Th:CaF$_2$ crystals

    CERN Document Server

    Stellmer, Simon; Schumm, Thorsten

    2015-01-01

    We study thorium-doped CaF$_2$ crystals as a possible platform for optical spectroscopy of the Th-229 nuclear isomer transition. We anticipate two major sources of background signal that might cover the nuclear spectroscopy signal: VUV-photoluminescence, caused by the probe light, and radioluminescence, caused by the radioactive decay of Th-229 and its daughters. We find a rich photoluminescence spectrum at wavelengths above 260 nm, and radioluminescence emission above 220 nm. This is very promising, as fluorescence originating from the isomer transition, predicted at a wavelength shorter than 200 nm, could be filtered spectrally from the crystal luminescence. Furthermore, we investigate the temperature-dependent decay time of the luminescence, as well as thermoluminescence properties. Our findings allow for an immediate optimization of spectroscopy protocols for both the initial search for the nuclear transition using synchrotron radiation, as well as future optical clock operation with narrow-linewidth lase...

  1. Direct β-C(sp(3))-H Functionalization of Aliphatic Amines to α,β-Unsaturated Imines, Aldehydes, and Chromenes.

    Science.gov (United States)

    Mandal, Sumana; Mahato, Sujit; Jana, Chandan K

    2015-08-01

    A metal-free method for direct β-C(sp(3))-H functionalization of aliphatic amine was developed. The method is based on a reaction that yields enamine directly from the corresponding aliphatic amine, which otherwise requires the aid of metallic reagent and/or external oxidant. The reaction is operationally simple, general, and highly efficient in functionalizing both cyclic and acyclic amines. Structurally diverse unsaturated imines were obtained from N-heterocycles, while acyclic amines provided 2-alkyl cinnamaldehyde and benzopyran derivatives with excellent E/Z-selectivity. PMID:26204435

  2. Enhanced Photoluminescence Properties of Carbon Dots by Doping with Europium.

    Science.gov (United States)

    Chen, Yuan; Xu, Jiafu; Liu, Bitao; Li, Jiyun; Fang, Xiaomei; Xiong, Liqiong; Peng, Lingling; Han, Tao; Tu, Mingjing

    2016-04-01

    Europium (Eu) doped carbon dots (CDs) were synthesized via a rapid and simple microwave medi- ated method using polyethylene glycol (PEG) as a precursor, and characterized in detail. The results were that these as-prepared CDs showed a uniform and small particle size, and exhibit good pho- tostability and high photoluminescence quantum yields. Additionally, it also found that the doped Eu would change the fluorescence properties, which indicates potential applications in the field of biolabeling. PMID:27451699

  3. Controlling carbon nanotube photoluminescence using silicon microring resonators

    OpenAIRE

    Noury, Adrien; Roux, Xavier Le; Vivien, Laurent; Izard, Nicolas

    2015-01-01

    We report on coupling between semiconducting single-wall carbon nanotubes (s-SWNT) photoluminescence and silicon microring resonators. Polyfluorene extracted s-SWNT deposited on such resonators exhibit sharp emission peaks, due to interaction with the cavity modes of the microring resonators. Ring resonators with radius of 5 {\\mu}m and 10 {\\mu}m were used, reaching quality factors up to 4000 in emission. These are among the highest values reported for carbon nanotubes coupled with an integrat...

  4. Nonlinear Photoluminescence Spectroscopy of Carbon Nanotubes with Localized Exciton States

    OpenAIRE

    Iwamura, Munechiyo; Akizuki, Naoto; Miyauchi, Yuhei; Mouri, Shinichiro; Shaver, Jonah; Gao, Zhenghong; Cognet, Laurent; Lounis, Brahim; Matsuda, Kazunari

    2014-01-01

    International audience We report distinctive nonlinear behavior of photoluminescence (PL) intensities from localized exciton states embedded in single-walled carbon nanotubes (SWNTs) at room temperature. We found that PL from the local states exhibits strong nonlinear behavior with increasing continuous-wave excitation power density, whereas free exciton PL shows only weak sublinear behavior. The strong saturation behavior was observed regardless of the origin of the local states, and foun...

  5. Exciton resonances quench the photoluminescence of zigzag carbon nanotubes

    OpenAIRE

    Reich, Stephanie; Thomsen, Christian; Robertson, John

    2005-01-01

    We show that the photoluminescence intensity of single-walled carbon nanotubes is much stronger in tubes with large chiral angles - armchair tubes - because exciton resonances make the luminescence of zigzag tubes intrinsically weak. This exciton-exciton resonance depends on the electronic structure of the tubes and is found more often in nanotubes of the +1 family. Armchair tubes do not necessarily grow preferentially with present growth techniques; they just have stronger luminescence. Our ...

  6. Enhancing and redirecting carbon nanotube photoluminescence by an optical antenna

    OpenAIRE

    Böhmler, Miriam; Hartmann, Nicolai; Georgi, Carsten; Hennrich, Frank; Green, Alexander A.; Hersam, Mark C.; Hartschuh, Achim

    2010-01-01

    We observe the angular radiation pattern of single carbon nanotubes' photoluminescence in the back focal plane of a microscope objective and show that the emitting nanotube can be described by a single in-plane point dipole. The near-field interaction between a nanotube and an optical antenna modifies the radiation pattern that is now dominated by the antenna characteristics. We quantify the antenna induced excitation and radiation enhancement and show that the radiative rate enhancement is c...

  7. Photoluminescence properties of Co-doped ZnO nanocrystals

    DEFF Research Database (Denmark)

    Lommens, P.; Smet, P.F.; De Mello Donega, C.;

    2006-01-01

    We performed photoluminescence experiments on colloidal, Co -doped ZnO nanocrystals in order to study the electronic properties of Co in a ZnO host. Room temperature measurements showed, next to the ZnO exciton and trap emission, an additional emission related to the Co dopant. The spectral posit...... revealed a paramagnetic behaviour. © 2005 Elsevier B.V. All rights reserved....

  8. UV-VIS and photoluminescence spectroscopy for nanomaterials characterization

    CERN Document Server

    2013-01-01

    Second volume of a 40-volume series on nanoscience and nanotechnology, edited by the renowned scientist Challa S.S.R. Kumar. This handbook gives a comprehensive overview about UV-visible and photoluminescence spectroscopy for the characterization of nanomaterials. Modern applications and state-of-the-art techniques are covered and make this volume essential reading for research scientists in academia and industry in the related fields.

  9. Fractals of graphene quantum dots in photoluminescence of shungite

    OpenAIRE

    RAZBIRIN B.S.; ROZHKOVA N.N.; Sheka, E. F.; Nelson, D. K.; Starukhin, A. N.; Goryunov, A. S.

    2013-01-01

    Photoluminescence of graphene quantum dots (GQDs) of shungite, attributed to individual fragments of reduced graphene oxide (rGO), has been studied for the frozen rGO colloidal dispersions in water, carbon tetrachloride, and toluene. Morphological study shows a steady trend of GQDs to form fractals and a drastic change in the colloids fractal structure caused by solvent was reliably established. Spectral study reveals a dual character of emitting centers: individual GQDs are responsible for t...

  10. Biodegradable foam plastics based on castor oil.

    Science.gov (United States)

    Wang, Hong Juan; Rong, Min Zhi; Zhang, Ming Qiu; Hu, Jing; Chen, Hui Wen; Czigány, Tibor

    2008-02-01

    In this work, a simple but effective approach was proposed for preparing biodegradable plastic foams with a high content of castor oil. First of all, castor oil reacted with maleic anhydride to produce maleated castor oil (MACO) without the aid of any catalyst. Then plastic foams were synthesized through free radical initiated copolymerization between MACO and diluent monomer styrene. With changes in MACO/St ratio and species of curing initiator, mechanical properties of MACO foams can be easily adjusted. In this way, biofoams with comparable compressive stress at 25% strain as commercial polyurethane (PU) foams were prepared, while the content of castor oil can be as high as 61 wt %. The soil burial tests further proved that the castor oil based foams kept the biodegradability of renewable resources despite the fact that some petrol-based components were introduced.

  11. BIODEGRADATION OF REGENERATED CELLULOSE FILMS BY FUNGI

    Institute of Scientific and Technical Information of China (English)

    ZHANG Lina; LIU Haiqing; ZHENG Lianshuang; ZHANG Jiayao; DU Yumin; LIU Weili

    1996-01-01

    The biodegradability of Aspergillus niger (A. niger), Mucor (M-305) and Trichoderma (T-311) strains on regenerated cellulose films in media was investigated. The results showed that T-311 strain isolated from soil adhered on the cellulose film fragments has stronger degradation effect on the cellulose film than A. niger strain. The weights, molecular weights and tensile strengths of the cellulose films in both shake culture and solid media decreased with incubation time, accompanied by producing CO2 and saccharides. HPLC, IR and released CO2 analysis indicated that the biodegradation products of the regenerated cellulose films mainly contain oligosaccharides, cellobiose, glucose, arabinose, erythrose, glycerose,glycerol, ethanal, formaldehyde and organic acid, the end products were CO2 and water.After a month, the films were completely decomposed by fungi in the media at 30℃.

  12. The Prestige oil spill. 2. Enhanced biodegradation of a heavy fuel oil under field conditions by the use of an oleophilic fertilizer.

    Science.gov (United States)

    Jiménez, Núria; Viñas, Marc; Sabaté, Jordi; Díez, Sergi; Bayona, Josep M; Solanas, Anna M; Albaiges, Joan

    2006-04-15

    A field bioremediation assay using the oleophilic fertilizer S200 was carried out 10 months after the Prestige heavy fuel-oil spill on a beach of the Cantabrian coast (North Spain). The field survey showed that S200 significantly enhanced the biodegradation rate, particularly of high molecular weight n-alkanes, alkylcyclohexanes, and benzenes, and alkylated PAHs, paralleling the results previously found in vitro. The most significant molecular bioremediation indicators were the depletion of diasteranes and C-27 sterane components. Enhanced isomeric selectivity was also observed within the C1-phenanthrenes and dibenzothiophenes. Through the analysis of some target aliphatic and aromatic hydrocarbons a number of chemical indicators for assessing the efficiency of field bioremediation as well as identifying the source of highly weathered samples collected in the area after the spill are defined.

  13. Photoluminescence from Amino-Containing Polymer in the Presence of CO2: Carbamato Anion Formed as a Fluorophore

    OpenAIRE

    Xiaoyong Pan; Guan Wang; Chee Leng Lay; Beng Hong Tan; Chaobin He; Ye Liu

    2013-01-01

    Organic photoluminescent materials are important to many applications especially for diagnosis and detection, and most of organic photoluminescent materials contain fluorophores with extended conjugated structures. Recently some of amino-containing polymers without fluorophores with extended conjugated structure are observed to be photoluminescent, and one possible cause of the photoluminescence is oxidation of the amines. Here we show that photoluminescence can be produced by exposing a typi...

  14. Photoluminescence and Raman Spectroscopy Studies of Carbon Nitride Films

    Directory of Open Access Journals (Sweden)

    J. Hernández-Torres

    2016-01-01

    Full Text Available Amorphous carbon nitride films with N/C ratios ranging from 2.24 to 3.26 were deposited by reactive sputtering at room temperature on corning glass, silicon, and quartz as substrates. The average chemical composition of the films was obtained from the semiquantitative energy dispersive spectroscopy analysis. Photoluminescence measurements were performed to determine the optical band gap of the films. The photoluminescence spectra displayed two peaks: one associated with the substrate and the other associated with CNx films located at ≈2.13±0.02 eV. Results show an increase in the optical band gap from 2.11 to 2.15 eV associated with the increase in the N/C ratio. Raman spectroscopy measurements showed a dominant D band. ID/IG ratio reaches a maximum value for N/C ≈ 3.03 when the optical band gap is 2.12 eV. Features observed by the photoluminescence and Raman studies have been associated with the increase in the carbon sp2/sp3 ratio due to presence of high nitrogen content.

  15. Photoluminescence properties of S2 molecule trapped in Melanophlogite

    Science.gov (United States)

    Messina, Fabrizio; Todaro, Michela; Buscarino, Gianpiero; Vaccaro, Lavinia; Cannas, Marco; Gelardi, Franco M.

    2016-03-01

    We studied the photoluminescence properties of a sample of SiO2-clathrate Melanophlogite, a crystalline microporous material which is found in nature as a rare mineral. Upon β irradiation, the material displays an intense light emission under near-UV illumination. We studied in detail this optical activity by steady-state and time-resolved photoluminescence measurements as a function of temperature. The spectroscopic properties we find can be ascribed to a population of quasi-free molecules trapped within each of the two different types of cage available in the structure of this clathrate, although the spectroscopic properties of the guest molecules are affected by their interactions with the host matrix. Based on the available data, we attribute the observed photoluminescence to trapped S2 molecules, emitting from their excited 3Σ u - or 3Π u electronic states, depending on the cage they are trapped in and on temperature. Our results have an impact on the fundamental understanding of host-guest interactions characteristic of microporous systems such as clathrates. Indeed, the data highlight that even a relatively weak coupling between quasi-free S2 molecules and the two types of cages provided by the Melanophlogite host has a surprisingly complex influence on the optical properties of the guest.

  16. Biodegradation of Petroleum Hydrocarbons in Soil

    OpenAIRE

    MR Mehrasbi; B Haghighi; M.Shariat; S Naseri; Naddafi, K

    2003-01-01

    Biodegradation of petroleum hydrocarbons (20 g/kg dw soil) was investigated in 3 media, differing in the kind of petroleum fractions. In the laboratory experiments, during 5 months, the activities of petroleum hydrocarbon-degrading microorganisms and dehydrogenase activity of soil was determined. Gas chromatographic analysis showed the biological decontaminations for gas oil, kerosene and synthetic mixture (gas oil, kerosene and furnace oil) are 60 %, 36 % and 55 %, respectively. Dehydrogenas...

  17. Assessment of polymer-based nanocomposites biodegradability

    OpenAIRE

    Machado, A.V.; Araújo, Andreia Isabel Silva; Oliveira, Manuel

    2015-01-01

    The management of solid waste is a growing concern in many countries. Municipal solid waste is a major component of the total solid waste generated by society, and the composting of municipal solid waste has gained some attention even though a composting treatment for it is not yet widespread. It may not be realistic to replace large portions of these plastics with biodegradable materials, and it may be more important to separate plastics unsuitable for the composting process at the generatin...

  18. Biodegradation of hexachlorocyclohexane (HCH) by microorganisms.

    Science.gov (United States)

    Phillips, Theresa M; Seech, Alan G; Lee, Hung; Trevors, Jack T

    2005-08-01

    The organochlorine pesticide Lindane is the gamma-isomer of hexachlorocyclohexane (HCH). Technical grade Lindane contains a mixture of HCH isomers which include not only gamma-HCH, but also large amounts of predominantly alpha-, beta- and delta-HCH. The physical properties and persistence of each isomer differ because of the different chlorine atom orientations on each molecule (axial or equatorial). However, all four isomers are considered toxic and recalcitrant worldwide pollutants. Biodegradation of HCH has been studied in soil, slurry and culture media but very little information exists on in situ bioremediation of the different isomers including Lindane itself, at full scale. Several soil microorganisms capable of degrading, and utilizing HCH as a carbon source, have been reported. In selected bacterial strains, the genes encoding the enzymes involved in the initial degradation of Lindane have been cloned, sequenced, expressed and the gene products characterized. HCH is biodegradable under both oxic and anoxic conditions, although mineralization is generally observed only in oxic systems. As is found for most organic compounds, HCH degradation in soil occurs at moderate temperatures and at near neutral pH. HCH biodegradation in soil has been reported at both low and high (saturated) moisture contents. Soil texture and organic matter appear to influence degradation presumably by sorption mechanisms and impact on moisture retention, bacterial growth and pH. Most studies report on the biodegradation of relatively low (sources or other soil amendments is scattered and inconclusive. More in-depth assessments of amendment effects and evaluation of bioremediation protocols, on a large scale, using soil with high HCH concentrations, are needed.

  19. FTIR study of degradation products of aliphatic polyesters carbon fibres composites

    Science.gov (United States)

    Pamuła, Elżbieta; Błażewicz, Marta; Paluszkiewicz, Czesława; Dobrzyński, Piotr

    2001-09-01

    Biodegradable polymer composites based on polylactides and polyglycolides constitute a group of materials characterised by good biocompatibility. They are considered in tissue engineering as scaffolds for cells proliferation and controlled tissue regeneration. Two types of biodegradable polymers possessing different chemical structure, molecular weights and crystallinity degrees and two composite materials made up of them and carbon fibres were analysed in this study. The samples were incubated in aqueous media for 8 weeks and analysed by means of Fourier transform infrared spectroscopy in the attenuated total reflection mode (FTIR-ATR). Infrared spectroscopy enabled identification of degradation products and estimation of the influence of carbon fibres on hydrolytic degradation of analysed polymers. Analysis of the infrared spectra showed that hydrolytic degradation process depends on chemical structure, molecular weight and crystallinity of polymers. Catalytic effect of carbon fibres at the initial stage of polymer degradation was observed. Further degradation is dependent on the properties of polymer.

  20. Titanate nanotube coatings on biodegradable photopolymer scaffolds

    Energy Technology Data Exchange (ETDEWEB)

    Beke, S., E-mail: szabolcs.beke@iit.it [Department of Nanophysics, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova (Italy); Kőrösi, L. [Department of Biotechnology, Nanophage Therapy Center, Enviroinvest Corporation, Kertváros u. 2, H-7632, Pécs (Hungary); Scarpellini, A. [Department of Nanochemistry, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova (Italy); Anjum, F.; Brandi, F. [Department of Nanophysics, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova (Italy)

    2013-05-01

    Rigid, biodegradable photopolymer scaffolds were coated with titanate nanotubes (TNTs) by using a spin-coating method. TNTs were synthesized by a hydrothermal process at 150 °C under 4.7 bar ambient pressure. The biodegradable photopolymer scaffolds were produced by mask-assisted excimer laser photocuring at 308 nm. For scaffold coating, a stable ethanolic TNT sol was prepared by a simple colloid chemical route without the use of any binding compounds or additives. Scanning electron microscopy along with elemental analysis revealed that the scaffolds were homogenously coated by TNTs. The developed TNT coating can further improve the surface geometry of fabricated scaffolds, and therefore it can further increase the cell adhesion. Highlights: ► Biodegradable scaffolds were produced by mask-assisted UV laser photocuring. ► Titanate nanotube deposition was carried out without binding compounds or additives. ► The titanate nanotube coating can further improve the surface geometry of scaffolds. ► These reproducible platforms will be of high importance for biological applications.

  1. Titanate nanotube coatings on biodegradable photopolymer scaffolds

    International Nuclear Information System (INIS)

    Rigid, biodegradable photopolymer scaffolds were coated with titanate nanotubes (TNTs) by using a spin-coating method. TNTs were synthesized by a hydrothermal process at 150 °C under 4.7 bar ambient pressure. The biodegradable photopolymer scaffolds were produced by mask-assisted excimer laser photocuring at 308 nm. For scaffold coating, a stable ethanolic TNT sol was prepared by a simple colloid chemical route without the use of any binding compounds or additives. Scanning electron microscopy along with elemental analysis revealed that the scaffolds were homogenously coated by TNTs. The developed TNT coating can further improve the surface geometry of fabricated scaffolds, and therefore it can further increase the cell adhesion. Highlights: ► Biodegradable scaffolds were produced by mask-assisted UV laser photocuring. ► Titanate nanotube deposition was carried out without binding compounds or additives. ► The titanate nanotube coating can further improve the surface geometry of scaffolds. ► These reproducible platforms will be of high importance for biological applications

  2. Biodegradation of ion-exchange media

    International Nuclear Information System (INIS)

    Ion-exchange media, both bead resins and powdered filter media, are used in nuclear power plants to remove radioactivity from process water prior to reuse or environmental discharge. Since the ion- exchange media are made from synthetic hydrocarbon-based polymers, they may be susceptible to damage from biological activity. The purpose of this study was to investigate some of the more basic aspects of biodegradation of ion-exchange media, specifically to evaluate the ability of microorganisms to utilize the ion-exchange media or materials sorbed on them as a food source. The ASTM-G22 test, alone and combined with the Bartha Pramer respirometric method, failed to indicate the biodegradability of the ion-exchange media. The limitation of these methods was that they used a single test organism. In later phases of this study, a mixed microbial culture was grown from resin waste samples obtained from the BNL High Flux Beam Reactor. These microorganisms were used to evaluate the susceptibility of different types of ion-exchange media to biological attack. Qualitative assessments of biodegradability were based on visual observations of culture growths. Greater susceptibility was associated with increased turbidity in solution indicative of bacterial growth, and more luxuriant fungal mycelial growth in solution or directly on the ion-exchange resin beads. 21 refs., 9 figs., 18 tabs

  3. Macmillan ring-free oil biodegradation project

    International Nuclear Information System (INIS)

    Crude oil processing at the Macmillan Ring-Free Oil Company facility (Macmillan Oil Refinery) began in approximately 1929. Operations produced naphtha, diesel fuel, insulating oil, lubricating oil, and asphalt until approximately 1987. The waste material generated by the process was Resource Conservation and Recovery Act (RCRA) listed waste K048-Dissolved Air Flotation (DAF) float containing volatile and semivolatile organic compounds. On-site unlined surface impoundments used to store DAF and crude oil wastes have periodically overflowed and contaminated two adjacent creeks. A series of extensive site investigation activities in 1992 and 1993 addressed tank and drum, asbestos, lagoon and groundwater contamination at the site. The results of the investigation indicated that the majority of the contamination is contained within 10 lagoons and surrounding soils. Volume calculations indicate that approximately 45,000 cubic yards of contaminated soils and sediments required treatment. A field simulation of biodegradation of these wastes in a land treatment unit was implemented during removal actions. Results of the remedy selection biodegradation assessment provided evidence of a 61 to 96 percent reduction in contaminant concentrations. These concentrations are below land disposal and health risk-based criteria. The technology of biodegradation meets the EPA criteria for inclusion in the potential remedies for the Macmillan Oil Refinery

  4. Bacterial production of the biodegradable plastics polyhydroxyalkanoates.

    Science.gov (United States)

    Urtuvia, Viviana; Villegas, Pamela; González, Myriam; Seeger, Michael

    2014-09-01

    Petroleum-based plastics constitute a major environmental problem due to their low biodegradability and accumulation in various environments. Therefore, searching for novel biodegradable plastics is of increasing interest. Microbial polyesters known as polyhydroxyalkanoates (PHAs) are biodegradable plastics. Life cycle assessment indicates that PHB is more beneficial than petroleum-based plastics. In this report, bacterial production of PHAs and their industrial applications are reviewed and the synthesis of PHAs in Burkholderia xenovorans LB400 is described. PHAs are synthesized by a large number of microorganisms during unbalanced nutritional conditions. These polymers are accumulated as carbon and energy reserve in discrete granules in the bacterial cytoplasm. 3-hydroxybutyrate and 3-hydroxyvalerate are two main PHA units among 150 monomers that have been reported. B. xenovorans LB400 is a model bacterium for the degradation of polychlorobiphenyls and a wide range of aromatic compounds. A bioinformatic analysis of LB400 genome indicated the presence of pha genes encoding enzymes of pathways for PHA synthesis. This study showed that B. xenovorans LB400 synthesize PHAs under nutrient limitation. Staining with Sudan Black B indicated the production of PHAs by B. xenovorans LB400 colonies. The PHAs produced were characterized by GC-MS. Diverse substrates for the production of PHAs in strain LB400 were analyzed.

  5. Biodegradability evaluation of polymers by ISO 14855-2.

    Science.gov (United States)

    Funabashi, Masahiro; Ninomiya, Fumi; Kunioka, Masao

    2009-10-01

    Biodegradabilities of polymers and their composites in a controlled compost were described. Polycaprolactone (PCL) and poly(lactic acid) (PLA) were employed as biodegradable polymers. Biodegradabilities of PCL and PLA samples in a controlled compost were measured using a Microbial Oxidative Degradation Analyzer (MODA) according to ISO 14855-2. Sample preparation method for biodegradation test according to ISO/DIS 10210 was also described. Effects of sizes and shapes of samples on biodegradability were studied. Reproducibility of biodegradation test of ISO 14855-2 by MODA was confirmed. Validity of sample preparation method for polymer pellets, polymer film, and polymer products of ISO/DIS 10210 for ISO 14855-2 was confirmed. PMID:20111676

  6. Mortality of Bemisia tabaci biotype B (sternorrhyncha: aleyrodidae adults by aliphatic and aromatic synthetic sucrose esters

    Directory of Open Access Journals (Sweden)

    Mariangela Alves

    2008-12-01

    Full Text Available The B-strain of Bemisia tabaci Gennadius is a key pest of several crops and chemical control is the main control method used by growers, although reduction in efficacy due to insecticide resistance has already been reported. The aim of this work was to investigate the insecticidal effect of an array of synthetic sucrose esters with the aliphatic and aromatic groups on whitefly adults. Sucrose butyrate, caprate, octanoate, palmitate, oleate, octaacetate, phthalate, benzoate, and sucrose diacetate hexaisobutyrate were tested. The solutions were prepared and applied on the adults caught on yellow sticky traps using the Potter spray tower. Long-chains sucrose aliphatic esters were more effective against the silverleaf whiteflies and the highest mortality was obtained with sucrose oleate and sucrose octanoate. Since these compounds were tensoactive, sodium dodecylsulphate was also tested for the comparison but no effect was observed. Sucrose butyrate and other aliphatic and aromatic sucrose polyesters showed negligible effect on the silverleaf whiteflies.O biótipo B de B. tabaci Gennadius tem se destacado como uma praga-chave de diversas culturas. O controle químico tem sido a principal tática de controle utilizada, embora já se tenha observado redução na eficiência dos produtos devido ao desenvolvimento de resistência. Assim, o objetivo do presente trabalho foi avaliar o efeito de diversos ésteres de sacarose com grupos alifáticos ou aromáticos sobre adultos de mosca-branca. Butirato de sacarose, caprato, octanoato, palmitato, oleato, actaacetato, ftlato, benzoato e diacetato hexaisobutirato de sacarose foram testados. Soluções de éster de sacarose foram preparadas e aplicadas sobre adultos capturados em armadilhas adesivas utilizando Torre de Potter. Ésteres alifáticos de sacarose com longas cadeias foram mais efetivos contra mosca-branca e as maiores taxas de mortalidade foram obtidas com oleato e octanoato de sacarose. Uma vez que

  7. Degradation of Oxo-Biodegradable Plastic by Pleurotus ostreatus

    OpenAIRE

    José Maria Rodrigues da Luz; Sirlaine Albino Paes; Mateus Dias Nunes; Marliane de Cássia Soares da Silva; Maria Catarina Megumi Kasuya

    2013-01-01

    Growing concerns regarding the impact of the accumulation of plastic waste over several decades on the environmental have led to the development of biodegradable plastic. These plastics can be degraded by microorganisms and absorbed by the environment and are therefore gaining public support as a possible alternative to petroleum-derived plastics. Among the developed biodegradable plastics, oxo-biodegradable polymers have been used to produce plastic bags. Exposure of this waste plastic to ul...

  8. Facile synthesis of PbWO4: Applications in photoluminescence and photocatalytic degradation of organic dyes under visible light

    Science.gov (United States)

    Saraf, Rohit; Shivakumara, C.; Behera, Sukanti; Nagabhushana, H.; Dhananjaya, N.

    2015-02-01

    Stolzite polymorph of PbWO4 catalyst was prepared by the facile room temperature precipitation method. Structural parameters were refined by the Rietveld analysis using powder X-ray data. PbWO4 was crystallized in the scheelite-type tetragonal structure with space group I41/a (No. 88). Field emission scanning electron microscopy revealed leaf like morphology. Photoluminescence spectra exhibit broad blue emission (425 nm) under the excitation of 356 nm. The photocatalytic degradation of Methylene blue, Rhodamine B and Methyl orange dyes were measured under visible illumination. The 100% dye degradation was observed for MB and RhB dyes within 60 and 105 min. The rate constant was found to be in the decreasing order of MB > RhB > MO which followed the 1st order kinetic mechanism. Therefore, PbWO4 can be a potential candidate for blue component in white LEDs and also acts as a catalyst for the treatment of toxic and non-biodegradable organic pollutants in water.

  9. Strawberry under low-tunnel protected with experimental biodegradable films

    International Nuclear Information System (INIS)

    A research was carried out in order to test innovative biodegradable materials for the protected cultivation of strawberry in Southern Italy. A field test was carried out in order to evaluate the agronomic performances of the biodegradable materials in comparison with non biodegradable LDPE materials. Different kinds of biodegradable black films were used for soil mulching and transparent biodegradable films for the covering of the low tunnels. Climatic data of the site, air temperature and relative humidity inside the low tunnels and soil temperature under the mulching films were gathered during the test. Besides, laboratory radiometric tests were executed on the films in order to evaluate parameters such as the transmissivity in different wavelength ranges. The biodegradable materials showed a high capacity to induce greenhouse effect due to their very low transmissivity in the long wave infrared range. The yield obtained using biodegradable materials was on average 12% higher then the one obtained with traditional films. Concerning the earliness, at the first day of the harvest, the yield obtained with biodegradable materials was 70% higher in comparison with the case of LDPE films. The research showed that the biodegradable materials could be a sustainable alternative to the plastic films based on fossil raw materials

  10. Critical evaluation of biodegradable polymers used in nanodrugs.

    Science.gov (United States)

    Marin, Edgar; Briceño, Maria Isabel; Caballero-George, Catherina

    2013-01-01

    Use of biodegradable polymers for biomedical applications has increased in recent decades due to their biocompatibility, biodegradability, flexibility, and minimal side effects. Applications of these materials include creation of skin, blood vessels, cartilage scaffolds, and nanosystems for drug delivery. These biodegradable polymeric nanoparticles enhance properties such as bioavailability and stability, and provide controlled release of bioactive compounds. This review evaluates the classification, synthesis, degradation mechanisms, and biological applications of the biodegradable polymers currently being studied as drug delivery carriers. In addition, the use of nanosystems to solve current drug delivery problems are reviewed.

  11. Influence of inorganic salt on aerobic biodegradability of dyestuffs

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    this paper, the influence of inorganic salt on aerobic biodegradability of dyestuffs was studied by means of semicontinuous activated sludge method. It was found that: biodegradability of dyestuffs would decrease with the increase of the concentration of NaCl; however, biodegradability in the condition of NaCl = 30 g/L was better than that in the condition of NaCl =15 g/L; in the three NaCl conditions, biodegradability of tasted dyestuffs followed the following order: NaCl= 0 g/L > NaCl= 30g/L>NaCl= 15 g/L.

  12. Silicon microneedles array with biodegradable tips for transdermal drug delivery

    CERN Document Server

    Chen, B; Tay, Francis; Wong, Y T; Iliescu, C

    2008-01-01

    This paper presents the fabrication process, characterization results and basic functionality of silicon microneedles array with biodegradable tips. In order to avoid the main problems related to silicon microneedles : broking of the top part of the needles inside the skin, a simple solution can be fabrication of microneedles array with biodegradable tips. The silicon microneedles array was fabricated by using reactive ion etching while the biodegradable tips were performed using and anodization process that generates selectively porous silicon only on the top part of the skin. The paper presents also the results of in vitro release of calcein using microneedles array with biodegradable tips

  13. Critical evaluation of biodegradable polymers used in nanodrugs.

    Science.gov (United States)

    Marin, Edgar; Briceño, Maria Isabel; Caballero-George, Catherina

    2013-01-01

    Use of biodegradable polymers for biomedical applications has increased in recent decades due to their biocompatibility, biodegradability, flexibility, and minimal side effects. Applications of these materials include creation of skin, blood vessels, cartilage scaffolds, and nanosystems for drug delivery. These biodegradable polymeric nanoparticles enhance properties such as bioavailability and stability, and provide controlled release of bioactive compounds. This review evaluates the classification, synthesis, degradation mechanisms, and biological applications of the biodegradable polymers currently being studied as drug delivery carriers. In addition, the use of nanosystems to solve current drug delivery problems are reviewed. PMID:23990720

  14. Biodegradation of flax fiber reinforced poly lactic acid

    Directory of Open Access Journals (Sweden)

    2010-07-01

    Full Text Available Woven and nonwoven flax fiber reinforced poly lactic acid (PLA biocomposites were prepared with amphiphilic additives as accelerator for biodegradation. The prepared composites were buried in farmland soil for biodegradability studies. Loss in weight of the biodegraded composite samples was determined at different time intervals. The surface morphology of the biodegraded composites was studied with scanning electron microscope (SEM. Results indicated that in presence of mandelic acid, the composites showed accelerated biodegradation with 20–25% loss in weight after 50–60 days. On the other hand, in presence of dicumyl peroxide (as additive, biodegradation of the composites was relatively slow as confirmed by only 5–10% loss in weight even after 80–90 days. This was further confirmed by surface morphology of the biodegraded composites. We have attempted to show that depending on the end uses, we can add different amphiphilic additives for delayed or accelerated biodegradability. This work gives us the idea of biodegradation of materials from natural fiber reinforced PLA composites when discarded carelessly in the environment instead of proper waste disposal site.

  15. Catalytic activity of carbon nanotubes in the conversion of aliphatic alcohols

    Science.gov (United States)

    Zhitnev, Yu. N.; Tveritinova, E. A.; Chernyak, S. A.; Savilov, S. V.; Lunin, V. V.

    2016-06-01

    Carbon nanotubes (CNTs) obtained via the catalytic pyrolysis of hexane at 750°C were studied as the catalysts in conversion of C2-C4 alcohols. The efficiency of CNTs as catalysts in dehydration and dehydrogenation of ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, and tert-butanol was studied by means of pulse microcatalysis. The surface and structural characteristics of CNTs are investigated via SEM, TEM, DTA, BET, and XPS. CNTs are shown to be effective catalysts in the conversion of alcohols and do not require additional oxidative treatment. The regularities of the conversion of aliphatic alcohols, related to the properties of the CNTs surface and the structure of the alcohols are identified.

  16. Kinetics and mechanism of oxidation of aliphatic primary alcohols by quinolinium bromochromate

    Indian Academy of Sciences (India)

    Sonu Saraswat; Vinita Sharma; K K Banerji

    2003-02-01

    Oxidation of nine aliphatic primary alcohols by quinolinium bromochromate (QBC) in dimethylsulphoxide leads to the formation of the corresponding aldehydes. The reaction is first order with respect to both QBC and the alcohol. The reaction is catalysed by hydrogen ions. The hydrogen-ion dependence has the form: obs = + [H+]. The oxidation of [1,1-2H2]ethanol (MeCD2OH) exhibits a substantial primary kinetic isotope effect. The reaction has been studied in nineteen different organic solvents. The solvent effect was analysed using Taft’s and Swain's multiparametric equations. The rate of oxidation is susceptible to both polar and steric effects of the substituents. A suitable mechanism has been proposed.

  17. Kinetics and mechanism of oxidation of aliphatic alcohols by tetrabutylammonium tribromide

    Indian Academy of Sciences (India)

    Manju Baghmar; Pradeep K Sharma

    2001-04-01

    Oxidation of nine primary aliphatic alcohols by tetrabutylammonium tribromide (TBATB) in aqueous acetic acid leads to the formation of the corresponding aldehydes. The reaction is first order with respect to TBATB. Michaelis-Menten type kinetics is observed with respect to alcohols. The reaction failed to induce the polymerization of acrylonitrile. Tetrabutylammonium chloride has no effect on the reaction rate. The proposed reactive oxidizing species is the tribromide ion. The oxidation of [1,1-2H2]ethanol exhibits a substantial kinetic isotope effect. The effect of solvent composition indicates that the rate increases with increase in the polarity of the solvent. The reaction is susceptible to both polar and steric effects of substituents. A mechanism involving transfer of a hydride ion in the ratedetermining step has been proposed.

  18. Low-temperature microchip nonaqueous capillary electrophoresis of aliphatic primary amines: applications to Titan chemistry.

    Science.gov (United States)

    Cable, Morgan L; Stockton, Amanda M; Mora, Maria F; Willis, Peter A

    2013-01-15

    We demonstrate microchip nonaqueous capillary electrophoresis (μNACE) analysis of primary aliphatic amines (C1-C18) in ethanol down to -20 °C as a first step in adapting microfluidic protocols for in situ analysis on Titan. To our knowledge, this is the first report of a nonaqueous separation at -20 °C on-chip. Limits of detection (LODs) ranged from 1.0 nM to 2.6 nM, and we identified several primary amines ranging in length from C2 to C16 in Titan aerosol analogue (tholin) samples; new amines were also detected in a tholin sample exposed to oxygen and liquid water. This preliminary work validates the sensitivity and efficacy of microfluidic chemical analysis of complex organics with relevance to Titan aerosols and surface deposits. PMID:23214444

  19. Electrochemical oxidation of aliphatic amines and their attachment to carbon and metal surfaces.

    Science.gov (United States)

    Adenier, Alain; Chehimi, Mohamed M; Gallardo, Iluminada; Pinson, Jean; Vilà, Neus

    2004-09-14

    The electrochemical oxidation of aliphatic amines (primary, secondary, and tertiary) has been investigated by cyclic voltammetry and preparative electrolysis. The oxidation mechanisms have been established, and the lifetimes of the radical cations have been measured for secondary and tertiary amines. These results have been put in parallel with the attachment of amines to glassy carbon, Au, and Pt electrodes by cyclic voltammetry, X-ray photoelectron spectroscopy (XPS), and infrared reflection-absorption spectroscopy (IRRAS). It is then possible to show that it is not the radical cation but the radical obtained after the deprotonation which reacts with the electrode surface. XPS results also point to the existence of a covalent bond between Au or Pt and the organic moiety.

  20. Purification of wet process phosphoric acid by solvent extraction with long-chain aliphatic amines

    International Nuclear Information System (INIS)

    Purification of phosphoric acid by solvent extraction with long-chain aliphatic amines is investigated. Extraction of cadmium is extensively examined regarding the importance of the aqueous phase, the diluent and the amine. The solubility of tri-n-octyl-amine is determined in water and phosphoric acid solutions. Properties of valuable constituent such as uranium and yttrium are screened. Modelling of the system is performed by adapting Bromley's model for electrolytes to the different dissociation/association equilibria in the aqueous phase. In the organic phase simple expressions are used for the non-ideal behaviour. Amine-acid equilibria are investigated for all acids present in industrial phosphoric acid. New extraction constants are calculated for phosphoric and hydro- fluosilic acid. Calculations are compared with experiments both from binary and multicomponent acid mixtures

  1. Modification of nano-sized layered double hydroxides by long-chain organic aliphatic surfactants

    Directory of Open Access Journals (Sweden)

    RAMASAMY ANBARASAN

    2008-03-01

    Full Text Available The inter-layer anion of layered double hydroxides (LDH with a hydrotalcite (HT-like structure was ion-exchanged with various organic surfactants, particularly with long chain aliphatic surfactants. After the ion-exchange process, the basal spacing of the LDH was increased and the increase of the basal spacing depended on various factors, such as the intercalation capacity functionality and orientation capability of the surfactant. Of the employed surfactants, stearic acid intercalated LDH showed the highest increase of the basal spacing, which was confirmed by XRD analysis. FTIR results supported the interaction of the surfactants with the LDH. In addition, an increase in the thermal stability of the dodecanedioic acid intercalated HT was evidenced by the TGA method.

  2. Platinum-Catalyzed, Terminal-Selective C(sp(3))-H Oxidation of Aliphatic Amines.

    Science.gov (United States)

    Lee, Melissa; Sanford, Melanie S

    2015-10-14

    This Communication describes the terminal-selective, Pt-catalyzed C(sp(3))-H oxidation of aliphatic amines without the requirement for directing groups. CuCl2 is employed as a stoichiometric oxidant, and the reactions proceed in high yield at Pt loadings as low as 1 mol%. These transformations are conducted in the presence of sulfuric acid, which reacts with the amine substrates in situ to form ammonium salts. We propose that protonation of the amine serves at least three important roles: (i) it renders the substrates soluble in the aqueous reaction medium; (ii) it limits binding of the amine nitrogen to Pt or Cu; and (iii) it electronically deactivates the C-H bonds proximal to the nitrogen center. We demonstrate that this strategy is effective for the terminal-selective C(sp(3))-H oxidation of a variety of primary, secondary, and tertiary amines. PMID:26439251

  3. Propargyl-functional aliphatic polycarbonate obtained from carbon dioxide and glycidyl propargyl ether.

    Science.gov (United States)

    Hilf, Jeannette; Frey, Holger

    2013-09-01

    The synthesis of propargyl-functional poly(carbonate)s with different content of glycidyl propargyl ether (GPE) units is achieved via the copolymerization of propargyl glycidyl ether and carbon dioxide. A new type of functional poly(carbonate) synthesized directly from CO(2) and the glycidyl ether is obtained. The resulting polymers show moderate polydispersities in the range of 1.6-2.5 and molecular weights in the range of 7000-10 500 g mol(-1). The synthesized copolymers with varying number of alkyne functionalities and benzyl azide are used for the copper-catalyzed Huisgen-1,3-dipolar addition. Moreover, the presence of vicinal alkyne groups opens a general pathway to produce functional aliphatic poly(carbonate)s from a single polymer scaffold.

  4. Synthesis and reactivity of aliphatic sulfur pentafluorides from substituted (pentafluorosulfanyl)benzenes.

    Science.gov (United States)

    Vida, Norbert; Václavík, Jiří; Beier, Petr

    2016-01-01

    Oxidation of 3- and 4-pentafluorosulfanyl-substituted anisoles and phenols with hydrogen peroxide and sulfuric acid provided a mixture of SF5-substituted muconolactone, maleic, and succinic acids. A plausible mechanism for the formation of the aliphatic SF5 compounds was presented and their chemical reactivity was investigated. SF5-substituted para-benzoquinone was synthesized; its oxidation led to an improved yield of 2-(pentafluorosulfanyl)maleic acid. The reaction of SF5-substituted maleic anhydride and para-benzoquinone with cyclopentadiene afforded the Diels-Alder adducts. Decomposition of 3-(pentafluorosulfanyl)muconolactone in acidic, neutral and basic aqueous media was investigated and the decarboxylation of 2-(pentafluorosulfanyl)maleic acid provided 3-(pentafluorosulfanyl)acrylic acid. PMID:26877813

  5. Direct optical observation of the formation of some aliphatic alcohol radicals. A pulse radiolysis study

    Indian Academy of Sciences (India)

    E Janata

    2002-12-01

    The kinetics of the reactions of hydroxyl radicals and hydrogen atoms with some aliphatic alcohols in aqueous solutions were studied using pulse radiolysis. Based on the increase in optical absorption in the UV region, the rate constants for the reaction of hydroxyl radicals and hydrogen atoms with methanol, ethanol, 2-propanol or -butyl alcohol were determined to be 9.0 × 108, 2.2 × 109, 2.0 × 109, 6.2 × 108 and 1.1 × 106, 1.8 × 107, 5.3 × 107, 2.3 × 105 dm3 mol-1 s-1 respectively. The bimolecular decay rate constants for the alcohol radicals produced in methanol and ethanol were evaluated to be 2 .4 × 109 and 1.5 × 109 dm3 mol-1 s-1. The values observed are in fairly good agreement with those reported earlier.

  6. Design, Synthesis and Cytotoxic Activities of Novel Aliphatic Amino-Substituted Flavonoids

    Directory of Open Access Journals (Sweden)

    Guannan Liu

    2013-11-01

    Full Text Available A series of flavonoids 9a–f, 13b, 13d, 13e and 14a–f bearing diverse aliphatic amino moieties were designed, synthesized and evaluated for their cytotoxic activities against the ECA-109, A-549, HL-60, and PC-3 cancer cell lines. Most of the compounds exhibited moderate to good activities. The structure-activity relationships were studied, revealing that the chalcone skeleton is the most preferable for cytotoxic activities. Chalcone 9d was the most promising compound due to its high potency against the examined cancer cell lines (its IC50 values against ECA-109, A549, HL-60 and PC-3 cells were 1.0, 1.5, 0.96 and 3.9 μM, respectively.

  7. A systems biology approach identifies a R2R3 MYB gene subfamily with distinct and overlapping functions in regulation of aliphatic glucosinolates.

    Directory of Open Access Journals (Sweden)

    Ida Elken Sønderby

    Full Text Available BACKGROUND: Glucosinolates are natural metabolites in the order Brassicales that defend plants against both herbivores and pathogens and can attract specialized insects. Knowledge about the genes controlling glucosinolate regulation is limited. Here, we identify three R2R3 MYB transcription factors regulating aliphatic glucosinolate biosynthesis in Arabidopsis by combining several systems biology tools. METHODOLOGY/PRINCIPAL FINDINGS: MYB28 was identified as a candidate regulator of aliphatic glucosinolates based on its co-localization within a genomic region controlling variation both in aliphatic glucosinolate content (metabolite QTL and in transcript level for genes involved in the biosynthesis of aliphatic glucosinolates (expression QTL, as well as its co-expression with genes in aliphatic glucosinolate biosynthesis. A phylogenetic analysis with the R2R3 motif of MYB28 showed that it and two homologues, MYB29 and MYB76, were members of an Arabidopsis-specific clade that included three characterized regulators of indole glucosinolates. Over-expression of the individual MYB genes showed that they all had the capacity to increase the production of aliphatic glucosinolates in leaves and seeds and induce gene expression of aliphatic biosynthetic genes within leaves. Analysis of leaves and seeds of single knockout mutants showed that mutants of MYB29 and MYB76 have reductions in only short-chained aliphatic glucosinolates whereas a mutant in MYB28 has reductions in both short- and long-chained aliphatic glucosinolates. Furthermore, analysis of a double knockout in MYB28 and MYB29 identified an emergent property of the system since the absence of aliphatic glucosinolates in these plants could not be predicted by the chemotype of the single knockouts. CONCLUSIONS/SIGNIFICANCE: It seems that these cruciferous-specific MYB regulatory genes have evolved both overlapping and specific regulatory capacities. This provides a unique system within which to

  8. Amperometric detection and electrochemical oxidation of aliphatic amines and ammonia on silver-lead oxide thin-film electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Ge, Jisheng

    1996-01-08

    This thesis comprises three parts: Electrocatalysis of anodic oxygen-transfer reactions: aliphatic amines at mixed Ag-Pb oxide thin-film electrodes; oxidation of ammonia at anodized Ag-Pb eutectic alloy electrodes; and temperature effects on oxidation of ethylamine, alanine, and aquated ammonia.

  9. Selective preparation of terminal alkenes from aliphatic carboxylic acids by a palladium-catalysed decarbonylation-eliminiation reaction

    NARCIS (Netherlands)

    Notre, le J.E.L.; Scott, E.L.; Franssen, M.C.R.; Sanders, J.P.M.

    2010-01-01

    Trialkylamines were used as additives in the decarbonylation–elimination reaction catalysed by the combination of palladium(II) chloride and DPE-Phos. Aliphatic carboxylic acids were transformed at relatively low temperature into terminal alkenes in high yield and high selectivity, without the need

  10. STUDY ON THE SEQUENCE STRUCTURE OF SBR BY 13C- NMR METHOD Ⅱ . PEAK ASSIGNMENT FOR ALIPHATIC CARBONS SPECTRA

    Institute of Scientific and Technical Information of China (English)

    JIAO Shuke; CHEN Xiaonong; HU Liping; YAN Baozhen

    1990-01-01

    The study on 13C-NMR spectra of aliphatic carbon region of emulsion-processed and solution-processed ( by lithium catalyst ) SBR was carried out. The assignments for more than thirty odd peaks observed experimentally were made by using " corresponding analysis " method, combined with the empirical parameters reported in literature. The peak intensities were calculated based on Bernoullian statistic assumption.

  11. Liquid-phase synthesis of bridged peptides using olefin metathesis of a protected peptide with a long aliphatic chain anchor.

    Science.gov (United States)

    Aihara, Keisuke; Komiya, Chiaki; Shigenaga, Akira; Inokuma, Tsubasa; Takahashi, Daisuke; Otaka, Akira

    2015-02-01

    Bridged peptides including stapled peptides are attractive tools for regulating protein-protein interactions (PPIs). An effective synthetic methodology in a heterogeneous system for the preparation of these peptides using olefin metathesis and hydrogenation of protected peptides with a long aliphatic chain anchor is reported.

  12. Metalloradical-Catalyzed Selective 1,2-Rh-H Insertion into the Aliphatic Carbon-Carbon Bond of Cyclooctane

    NARCIS (Netherlands)

    Y.W. Chan; B. de Bruin; K.S. Chan

    2015-01-01

    The selective aliphatic carboncarbon activation of cyclo-octane (c-octane) was achieved via the Rh-II(ttp)-catalyzed 1,2-addition of Rh(ttp)H to give Rh(ttp)(n-octyl) (ttp = tetratolylporphyrinato dianion) in good yield under mild reaction conditions. This mechanism is further supported by DFT calcu

  13. Structural characterisation of aliphatic, non-hydrolyzable biopolymers in freshwater algae and a leaf cuticle by ruthenium tetroxide degradation

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Schouten, S.; Moerkerken, P.; Gelin, F.; Baas, M.; Leeuw, J.W. de

    1998-01-01

    Aliphatic, non-hydrolyzable biopolymers were subjected to RuO4-oxidation in order to examine the potential of this method in revealing details on their structures. The method was tested on model compounds first and found to cleave alkyl chains of aromatic moieties, double bonds and ether bonds. Oxid

  14. Intramolecular Acylation of Aryl- and Aroyl-Aliphatic Acids by the Action of Pyrophosphoryl Chloride and Phosphorus Oxychloride

    Directory of Open Access Journals (Sweden)

    Saleh Rayyan

    2001-03-01

    Full Text Available Both pyrophosphoryl chloride and phosphorus oxychloride react with aryl aliphatic acids to form mixed anhydrides which undergo intramolecular acylation to afford cyclic ketones without the addition of a Friedel-Crafts catalyst. Aryl and aroylbenzoic acids could be cyclized to the corresponding anthrones and anthraquinones respectively.

  15. STUDIES ON MISCIBILITY OF POLY (ε-CAPROLACTONE) AND ALIPHATIC POLYCARBONATE BLENDS AND DETERMINATION OF THEIR INTERACTION PARAMETER

    Institute of Scientific and Technical Information of China (English)

    CHEN Li; HUANG Yuhui; SONG Mo; CONG Guangmin

    1992-01-01

    In this paper the miscibility of poly (ε-caprolactone) (PCL) and aliphatic polycarbonate (AP C) is studied by using DSC. The results show that PCL and APC are miscible in all ranges of composition. The interaction parameter between the polymers is calculated from the melting point depression data. Using optical microscope, the shapes of the PCL spherulites in the blends are observed.

  16. Ru/Me-BIPAM-Catalyzed Asymmetric Addition of Arylboronic Acids to Aliphatic Aldehydes and α-Ketoesters

    Directory of Open Access Journals (Sweden)

    Momoko Watanabe

    2011-06-01

    Full Text Available A ruthenium-catalyzed asymmetric arylation of aliphatic aldehydes and α-ketoesters with arylboronic acids has been developed, giving chiral alkyl(arylmethanols and α-hydroxy esters in good yields. The use of a chiral bidentate phosphoramidite ligand (Me-BIPAM achieved excellent enantioselectivities.

  17. The impact of the absence of aliphatic glucosinolates on water transport under salt stress in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Mcarmen eMartinez-Ballesta

    2015-07-01

    Full Text Available Members of the Brassicaceae are known for their contents of nutrients and health-promoting phytochemicals, including glucosinolatesExposure to salinity increases the levels of several of these compounds, but their role in abiotic stress response is unclear. The effect of aliphatic glucosinolates on plant water balance and growth under salt stress, involving aquaporins, was investigated by means of Arabidopsis thaliana mutants impaired in aliphatic glucosinolate biosynthesis, which is controlled by two transcription factors: Myb28 and Myb29. The double mutant myb28myb29, completely lacking aliphatic glucosinolates, was compared to wild type Col-0 (WT and the single mutant myb28. A greater reduction in the hydraulic conductivity of myb28myb29 was observed under salt stress, when compared to the WT and myb28; this correlated with the abundance of both PIP1 and PIP2 aquaporin subfamilies. Also, changes in root architecture in response to salinity were genotype dependent. Treatment with NaCl altered glucosinolates biosynthesis in a similar way in WT and the single mutant and differently in the double mutant. The results indicate that short-chain aliphatic glucosinolates may contribute to water saving under salt stress

  18. Preparation and characterization of protein loaded microspheres based on a hydroxylated aliphatic polyester, poly (lactic-co-hydroxymethyl glycolic acid)

    NARCIS (Netherlands)

    Ghassemi, A.H.; van Steenbergen, M.J.; Talsma, H.; van Nostrum, C.F.; Jiskoot, W.; Crommelin, D.J.A.; Hennink, W.E.

    2009-01-01

    The purpose of this study was to investigate the suitability of a novel hydroxylated aliphatic polyester, poly (lactic-co-hydroxymethyl glycolic acid) (PLHMGA), as controlled release system for pharmaceutical proteins. Dextran Blue (as a macromolecular model compound) and lysozyme-loaded PLHMGA and

  19. Analysis of aliphatic carboxylic acids in anaerobic digestion process waters by ion-exclusion chromatography

    Institute of Scientific and Technical Information of China (English)

    Kazuaki ITO; Kazuhiko TANAKA; Jun SAKAMOTO; Kazuya NAGAOKA; Yohichi TAKAYAMA; Takashi KANAHORI; Hiroshi SUNAHARA; Tsuneo HAYASHI; Shinji SATO; Takeshi HIROKAWA

    2012-01-01

    The analysis of seven aliphatic carboxylic acids ( formic,acetic,propionic,iso-butyric,n-butyric,iso-valeric and n-valeric acid) in anaerobic digestion process waters for biogas production was examined by ion-exclusion chromatography with dilute acidic eluents (benzoic acid,perfluorobutyric acid (PFBA) and sulfuric acid) and non-suppressed conductivity/ultraviolet (UV) detection.The columns used were a styrene/divinylbenzene-based strongly acidic cation-exchange resin column ( TSKgel SCX) and a polymethacrylate-based weakly acidic cation-exchange resin column ( TSKgel Super IC-A/C ).Good separation was performed on the TSKgel SCX in shorter retention times.For the TSKgel Super IC-A/C,peak shape of the acids was sharp and symmetrical in spite of longer retention times.In addition,the mutual separation of the acids was good except for iso- and n-butyric acids.The better separation and good detection was achieved by using the two columns (TSKgel SCX and TSKgel Super IC-A/C connected in series),lower concentrations of PFBA and sulfuric acid as eluents,non-suppressed conductivity detection and UV detection at 210 nm.This analysis was applied to anaerobic digestion process waters.The chromatograms with conductivity detection were relatively simpler compared with those of UV detection.The use of two columns with different selectivities for the aliphatic carboxylic acids and the two detection modes was effective for the determination and identification of the analytes in anaerobic digestion process waters containing complex matrices.

  20. Seasonal variation of aliphatic amines in marine sub-micrometer particles at the Cape Verde islands

    Directory of Open Access Journals (Sweden)

    C. Müller

    2009-07-01

    Full Text Available Monomethylamine (MA, dimethylamine (DMA and diethylamine (DEA were detected at non-negligible concentrations in sub-micrometer particles at the Cap Verde Atmospheric Observatory (CVAO located on the island of São Vicente in Cape Verde during algal blooms in 2007. The concentrations of these amines in five stage impactor samples ranged from 0 to 30 pg m−3 for MA, 130 to 360 pg m−3 for DMA and 5 to 110 pg m−3 for DEA during the spring bloom in May 2007 and 2 to 520 pg m−3 for MA, 100 to 1400 pg m−3 for DMA, 90 to 760 pg m−3 for DEA during an unexpected winter algal bloom in December 2007. Anomalously high Saharan dust deposition and intensive ocean layer deepening were found at the Atmospheric Observatory and the associated Ocean Observatory during algal bloom periods. The highest amine concentrations in fine particles (impactor stage 2, 0.14–0.42 μm indicates that amines are likely taken up from the gas phase into the acidic sub-micrometer particles. The contribution of amines to the organic carbon (OC content ranged from 0.2 to 2.5%C in the winter months, indicating the importance of this class of compounds to the carbon cycle in the marine environment. Furthermore, aliphatic amines originating from marine biological sources likely contribute significantly to the organic nitrogen in the marine atmosphere. The average contribution of the amines to the total detected nitrogen content in submicron particles can be non-negligible, especially in the winter months (0.1% N to 1.5% N in the sum of nitrate, ammonium and amines. This indicates that these smaller aliphatic amines can be important for the carbon and the nitrogen cycles in the remote marine environment.

  1. Occurrence of selected aliphatic amines in source water of major cities in China

    Institute of Scientific and Technical Information of China (English)

    Haifeng Zhang; Shuoyi Ren; Jianwei Yu; Min Yang

    2012-01-01

    The formation of toxic nitrogenous disinfection byproducts (N-DBPs),such as nitrosamines,halonitromethanes and haloacetonitriles,from reactions between chlorine/chloramine and dissolved organic nitrogen in drinking water has caused great concern with regarding public health.This study revealed the occurrence of 17 aliphatic amines,some of which have been confirmed to be the precursors of N-DBPs,in source water across China.A sensitive method based on benzenesulfonyl chloride derivatization and liquid-liquid extraction followed by GC-MS analysis was established for the simultaneous analysis of the selected amines in aqueous samples.In total,37 source water samples from the capital cities of 20 provinces were collected for the survey.Among the 17 amines,14 were detected with an average frequency of detection of 36%.The most relevant amines in terms of frequency and maximum concentrations detected were dimethylamine (100%,24.82 μg/L),methylamine (78%,0.92 μg/L),N-methylethylamine (70%,8.84 μg/L),propylamine (59%,10.69 μg/L),diethylamine (54%,3.76 μg/L),N-methylbutylamine (35%,3.07 μg/L),N-ethylpropylamine (35%,0.52 μg/L),and piperidine (32%,2.35 μg/L).This is the first large scale survey of the aliphatic amines occurrence in source water in the world.The wide presence of nitrosamine precursors like dimethylamine,N-methylethylamine and diethylamine,and the precursors of haloacetonitriles and halonitromethanes like methylamine and propylamine suggests that better source water management is required to ensure the safety of drinking water.

  2. Analysis of aliphatic waxes associated with root periderm or exodermis from eleven plant species.

    Science.gov (United States)

    Kosma, Dylan K; Rice, Adam; Pollard, Mike

    2015-09-01

    Aliphatic waxes can be found in association with suberized tissues, including roots. Non-polar lipids were isolated by rapid solvent extraction of mature regions of intact roots from eleven angiosperms, including both monocots and dicots. The majority of roots analyzed were taproots or tuberous taproots that had undergone secondary growth and thus were covered by a suberized periderm. The exceptions therein were maize (Zea mays L.) and rice (Oryza sativa L.), which present a suberized exodermis. The analysis herein focused on aliphatic waxes, with particular emphasis on alkyl hydroxycinnamates (AHCs). AHCs were widely distributed, absent from only one species, were found in both aerial and subterranean portions of tuberous taproots, and were associated with the fibrous roots of both maize and rice. Most species also contained monoacylglycerols, fatty alcohols and/or free fatty acids. Carrot (Daucus carrota L.) was the outlier, containing only free fatty acids, sterols, and polyacetylenes as identified components. Sterols were the only ubiquitous component across all roots analyzed. Monoacylglycerols of ω-hydroxy fatty acids were present in maize and rice root waxes. For species within the Brassiceae, wax compositions varied between subspecies or varieties and between aerial and subterranean portions of taproots. In addition, reduced forms of photo-oxidation products of ω-hydroxy oleate and its corresponding dicarboxylic acid (10,18-dihydroxy-octadec-8-enoate, 9,18-dihydroxy-octadec-10-enoate and 9-hydroxyoctadec-10-ene-1,18-dioate) were identified as naturally occurring suberin monomers in rutabaga (Brassica napus subsp. rapifera Metzg.) periderm tissues.

  3. w,w'-端羟基脂肪族聚碳酸酯的合成、性质和应用%Synthesis Property and Application of w,w'-Hydroxyl-Ended Aliphatic Polycarbonate Polyols

    Institute of Scientific and Technical Information of China (English)

    刘保华; 陈立班

    2002-01-01

      w,w'-Hydroxyl-ended aliphatic polycarbonate polyols (APC-Polyols) are resin materials developed in the recent three decades. They can be obtained by phosgene reaction, ester exchange reaction, and ring-opening polymerization of cyclocarbonates, and can also be prepared by regulated copolymerization of CO2 and epoxides, which is a process significant for effective utilization of CO2. Some of these resins exhibit special properties such as low decomposition temperature, good biocompatibility, or obvious biodegradability. They have found wide applications in the areas of polyurethane, adhesives, surfactants and so on. The topic is reviewed with 19 references.%  w,w'-端羟基脂肪族聚聚碳酸酯是最近30年发展起来的一种新型高分子材料,它可以通过光气法、酯交换法、开环聚合法和调节聚合法合成。这类树脂具有一些独特性能,如较低的分解温度、较好的生物相容性和生物降解性。它可以广泛应用于聚氨酯、粘合剂、表面活性剂等领域。

  4. Gate-induced blueshift and quenching of photoluminescence in suspended single-walled carbon nanotubes

    OpenAIRE

    Yasukochi, S.; Murai, T.; Moritsubo, S.; Shimada, T; Chiashi, S.; Maruyama, S.; Kato, Y. K.

    2011-01-01

    Gate-voltage effects on photoluminescence spectra of suspended single-walled carbon nanotubes are investigated. Photoluminescence microscopy and excitation spectroscopy are used to identify individual nanotubes and to determine their chiralities. Under an application of gate voltage, we observe slight blueshifts in the emission energy. In addition, we find that the photoluminescence intensity decreases exponentially with gate voltage. Quenching of the K-momentum exciton emission is also obser...

  5. Gate-induced blueshift and quenching of photoluminescence in suspended single-walled carbon nanotubes

    OpenAIRE

    Yasukochi, S.; Murai, T.; Moritsubo, S.; Shimada, T; Chiashi, S.; Maruyama, S.; Kato, Y. K.

    2011-01-01

    Gate-voltage effects on photoluminescence spectra of suspended single-walled carbon nanotubes are investigated. Photoluminescence microscopy and excitation spectroscopy are used to identify individual nanotubes and to determine their chiralities. Under an application of gate voltage, we observe slight blueshifts in the emission energy and strong quenching of photoluminescence. The blueshifts are similar for different chiralities investigated, suggesting extrinsic mechanisms. In addition, we f...

  6. Quantum dots-nanogap metamaterials fabrication by self-assembly lithography and photoluminescence studies.

    Science.gov (United States)

    Tripathi, Laxmi Narayan; Kang, Taehee; Bahk, Young-Mi; Han, Sanghoon; Choi, Geunchang; Rhie, Jiyeah; Jeong, Jeeyoon; Kim, Dai-Sik

    2015-06-01

    We present a new and versatile technique of self-assembly lithography to fabricate a large scale Cadmium selenide quantum dots-silver nanogap metamaterials. After optical and electron microscopic characterizations of the metamaterials, we performed spatially resolved photoluminescence transmission measurements. We obtained highly quenched photoluminescence spectra compared to those from bare quantum dots film. We then quantified the quenching in terms of an average photoluminescence enhancement factor. A finite difference time domain simulation was performed to understand the role of an electric field enhancement in the nanogap over this quenching. Finally, we interpreted the mechanism of the photoluminescence quenching and proposed fabrication method of new metamaterials using our technique.

  7. ESTIMATION OF BIODEGRADATION AND BIO-CORROSION OF MATERIALS IN NATURAL ENVIRONMENTS

    Directory of Open Access Journals (Sweden)

    Varchenko E. A.

    2014-12-01

    Full Text Available The article analyzes the problems that arise when evaluating biodegradation of materials, items, structures and products in natural environments.. The causes of biodegradations are revealed

  8. Sociobiology of biodegradation and the role of predatory protozoa in biodegrading communities

    Indian Academy of Sciences (India)

    Tejashree Modak; Shalmali Pradhan; Milind Watve

    2007-06-01

    Predatory protozoa are known to enhance biodegradation by bacteria in a variety of systems including rumen. This is apparently counterintuitive since many protozoa do not themselves produce extracellular degradative enzymes and prey upon bacterial degraders. We propose a mechanism of protozoal enhancement of bacterial biodegradation based on the sociobiology of biodegradation. Since extracellular enzyme production by degraders involves a cost to the bacterial cell, cheaters that do not make the enzyme will have a selective advantage. In the presence of cheaters, degraders that physically attach to water-insoluble substrate will have a selective advantage over free-floating degraders. On the other hand, cheaters will benefit by being free floaters since they consume the solubilized products of extracellular enzymes. Predatory ciliated protozoa are more likely to consume free-floating cheaters. Thus, due to protozoan predation a control is exerted on the cheater population. We illustrate the dynamics of such a system with the help of a computer simulation model. Available data on rumen and other biodegradation systems involving protozoa are compatible with the assumptions and predictions of the model.

  9. Biodegradable and semi-biodegradable composite hydrogels as bone substitutes: morphology and mechanical characterization.

    Science.gov (United States)

    Sanginario, V; Ginebra, M P; Tanner, K E; Planell, J A; Ambrosio, L

    2006-05-01

    Biodegradable and semi-biodegradable composite hydrogels are proposed as bone substitutes. They consist of an hydrophilic biodegradable polymer (HYAFF 11) as matrix and two ceramic powders (alpha-TCP and HA) as reinforcement. Both components of these composites have been of great interest in biomedical applications due to their excellent biocompatibility and tissue interactions, however they have never been investigated as bone substitute composites. Morphological and mechanical analysis have shown that the two fillers behave in a very different way. In the HYAFF 11/alpha-TCP composite, alpha-TCP is able to hydrolyze in contact with water while in the HYAFF 11 matrix. As a result, the composite sets and hardens, and entangled CDHA crystals are formed in the hydrogel phase and increases in the mechanical properties are obtained. In the HYAFF11/HA composite the ceramic reinforcement acts as inert phase leading to lower mechanical properties. Both mechanical properties and microstructure analysis have demonstrated the possibility to design hydrophilic biodegradable composite structures for bone tissue substitution applications. PMID:16688585

  10. Biodegradable Long-Circulating Polymeric Nanospheres

    Science.gov (United States)

    Gref, Ruxandra; Minamitake, Yoshiharu; Peracchia, Maria Teresa; Trubetskoy, Vladimir; Torchilin, Vladimir; Langer, Robert

    1994-03-01

    Injectable nanoparticulate carriers have important potential applications such as site-specific drug delivery or medical imaging. Conventional carriers, however, cannot generally be used because they are eliminated by the reticulo-endothelial system within seconds or minutes after intravenous injection. To address these limitations, monodisperse biodegradable nanospheres were developed from amphiphilic copolymers composed of two biocompatible blocks. The nanospheres exhibited dramatically increased blood circulation times and reduced liver accumulation in mice. Furthermore, they entrapped up to 45 percent by weight of the drug in the dense core in a one-step procedure and could be freeze-dried and easily redispersed without additives in aqueous solutions.

  11. Lipase biocatalysis for useful biodegradable products

    Energy Technology Data Exchange (ETDEWEB)

    Linko, Y.Y.; Wang, Zhuo Lin; Uosukainen, E.; Seppaelae, J. [Helsinki Univ. of Technology, Espoo (Finland); Laemsae, M. [Raisio Group Oil Milling Industry, Raisio (Finland)

    1996-12-31

    It was shown that lipases can be used as biocatalysts in the production of useful biodegradable compounds such as 1-butyl oleate by direct esterification of butanol and oleic acid to decrease viscosity of biodiesel in winter use. By enzymic transesterification, a mixture of 2-ethyl-1-hexyl esters from rapeseed oil fatty acids can be obtained in good yields for use as a solvent, and of trimethylolpropane esters for use as a lubricant. Finally, it was demonstrated that polyesters with a mass average molar mass in excess of 75,000 g mol{sup -}1 can be obtained by esterification or transesterification by using lipase as biocatalyst. (author) (3 refs.)

  12. Development of biodegradable fungicide by radiation

    International Nuclear Information System (INIS)

    To develop the fungicide which is biodegradable and alternative to chemical pesticide that has an side effect of environmental pollution, Mutant induction of the enhanced antifungal activity was studied by using radiation. Characteristics and structure of antifungal biomaterials derived from these mutants were analysed. Two biomaterials related to the antifungal activity from the above mutant were isolated and purified. Microbial pesticide were manufactured in combination of various additives. Antiphytopathogenic effects were proven by pot experiment and It was promising to prevent pepper, Chinese cabbage and radish from anthrax, phytophthora and root rot

  13. Development of biodegradable fungicide by radiation

    International Nuclear Information System (INIS)

    To develop the fungicide which is biodegradable and alternative to chemical pesticide that has an side effect of environmental pollution, Mutant induction of the enhanced antifungal activity was studied by using radiation. Characteristics and structure of antifungal biomaterials derived from these mutants were analysed. Sixteen antifungal microbes were isolated and 4 antifungal activity enhanced mutants were induced by using radiation. P. lentimorbus WJ5a17 had 41% higher antifungal activity than the wild type. Two biomaterials related to the antifungal activity from the above mutant were isolated and purified

  14. Development of biodegradable fungicide by radiation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Youngkeun; Kim, Dongsub

    2012-03-15

    To develop the fungicide which is biodegradable and alternative to chemical pesticide that has an side effect of environmental pollution, Mutant induction of the enhanced antifungal activity was studied by using radiation. Characteristics and structure of antifungal biomaterials derived from these mutants were analysed. Two biomaterials related to the antifungal activity from the above mutant were isolated and purified. Microbial pesticide were manufactured in combination of various additives. Antiphytopathogenic effects were proven by field test and it was promising to prevent Chinese cabbage and radish from phytophthora and root rot.

  15. Development of biodegradable fungicide by radiation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Young Keun; Kim, Dong Sub [KAERI, Daejeon (Korea, Republic of)

    2011-01-15

    To develop the fungicide which is biodegradable and alternative to chemical pesticide that has an side effect of environmental pollution, Mutant induction of the enhanced antifungal activity was studied by using radiation. Characteristics and structure of antifungal biomaterials derived from these mutants were analysed. Two biomaterials related to the antifungal activity from the above mutant were isolated and purified. Microbial pesticide were manufactured in combination of various additives. Antiphytopathogenic effects were proven by pot experiment and It was promising to prevent pepper, Chinese cabbage and radish from anthrax, phytophthora and root rot

  16. Biodegradation of petroleum hydrocarbons in hypersaline environments

    Directory of Open Access Journals (Sweden)

    Luiz Fernando Martins

    2012-09-01

    Full Text Available Literature on hydrocarbon degradation in extreme hypersaline media presents studies that point to a negative effect of salinity increase on hydrocarbonoclastic activity, while several others report an opposite tendency. Based on information available in the literature, we present a discussion on the reasons that justify these contrary results. Despite the fact that microbial ability to metabolize hydrocarbons is found in extreme hypersaline media, indeed some factors are critical for the occurrence of hydrocarbon degradation in such environments. How these factors affect hydrocarbon degradation and their implications for the assessment of hydrocarbon biodegradation in hypersaline environments are presented in this review.

  17. Biodegradation of the Nitramine Explosive CL-20

    OpenAIRE

    Trott, Sandra; Nishino, Shirley F.; Hawari, Jalal; Spain, Jim C.

    2003-01-01

    The cyclic nitramine explosive CL-20 (2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane) was examined in soil microcosms to determine whether it is biodegradable. CL-20 was incubated with a variety of soils. The explosive disappeared in all microcosms except the controls in which microbial activity had been inhibited. CL-20 was degraded most rapidly in garden soil. After 2 days of incubation, about 80% of the initial CL-20 had disappeared. A CL-20-degrading bacterial strain, Agrobact...

  18. Biodegradable long-circulating polymeric nanospheres.

    Science.gov (United States)

    Gref, R; Minamitake, Y; Peracchia, M T; Trubetskoy, V; Torchilin, V; Langer, R

    1994-03-18

    Injectable nanoparticulate carriers have important potential applications such as site-specific drug delivery or medical imaging. Conventional carriers, however, cannot generally be used because they are eliminated by the reticulo-endothelial system within seconds or minutes after intravenous injection. To address these limitations, monodisperse biodegradable nanospheres were developed from amphiphilic copolymers composed of two biocompatible blocks. The nanospheres exhibited dramatically increased blood circulation times and reduced liver accumulation in mice. Furthermore, they entrapped up to 45 percent by weight of the drug in the dense core in a one-step procedure and could be freeze-dried and easily redispersed without additives in aqueous solutions.

  19. Photoluminescence of multiwalled carbon nanotubes excited at different wavelengths

    Institute of Scientific and Technical Information of China (English)

    Yuan Yan-Hong; Miao Run-Cai; Bai Jin-Tao; Hou Xun

    2006-01-01

    In this paper the multiwalled carbon nanotubes (MWNTs) were synthesized by a chemical vapour deposition and the SEM graph shows that the sample has good construction. The micro-Raman spectrum shows the characteristic line of the MWNTs and an additional line produced by the defects on the outer surface of MWNTs. The photoluminescence (PL) spectra observed experimentally are variable under different excitation wavelengths and the strong excitation wavelength dependence of luminescence indicates a distribution of emitters which include electron π in excited states and the Van Hove singularities. The absorption spectra confirm the transition channels which are consistent with the PL emission.

  20. Van Hove singularities and nonlinear photoluminescence in multiwalled carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    YUAN Yan-hong; MIAO Run-cai; LIU Bao-ying

    2006-01-01

    The absorption spectrum and photoluminescence spectrum of multiwalled carbon nanotubes(MWNTs) and the peaks related with Van Hove singularities(VHS) were obtained experimentally.Both the VHS formation and the change of band gaps in MWNTs depend on the intershell interaction.The VHS makes the probability of optical transitions enhanced,but the intershell interaction suppresses such radiative transitions.The excitation in the experiment involves a two-photon absorption process and the emission light has the effect of the optical frequency up-conversion.

  1. Enhancement of semiconducting single-wall carbon nanotubes photoluminescence

    OpenAIRE

    Gaufrès, Etienne; Izard, Nicolas; Vivien, Laurent; Kazaoui, Saïd; Marris-Morini, Delphine; Cassan, Eric

    2009-01-01

    International audience Photoluminescence properties of semiconducting single wall carbon nanotubes (s-SWNT) thin films with different metallic single wall carbon nanotubes (m-SWNT) concentrations are reported. s-SWNT purified samples are obtained by polymer assisted selective extraction. We show that a few m-SWNT in the sample generates a drastic quenching of the emission. Therefore, highly purified s-SWNT films are a strongly luminescent material and a good candidate for future applications in...

  2. INCREASING THE PHOTOLUMINESCENCE INTENSITY OF Ge ISLANDS BY CHEMICAL ETCHING

    Institute of Scientific and Technical Information of China (English)

    高斐; 黄昌俊; 黄大定; 李建平; 孔梅影; 曾一平; 李晋闽; 林兰英

    2001-01-01

    Self-assembled Ge islands were grown on Si(100) substrate by Si2H6-Ge molecular beam epitaxy. After beingsubjected to chemical etching, it is found that the photoluminescence from the etched Ge islands became more intense and shifted to the higher-energy side compared to that of the as-deposited Ge islands. This behaviour was explained by the effect of chemical etching on the morphology of the Ge islands. Our results demonstrate that chemical etching can be a way to change the luminescence property of the as-deposited islands.

  3. Controlling carbon nanotube photoluminescence using silicon microring resonators

    CERN Document Server

    Noury, Adrien; Vivien, Laurent; Izard, Nicolas

    2015-01-01

    We report on coupling between semiconducting single-wall carbon nanotubes (s-SWNT) photoluminescence and silicon microring resonators. Polyfluorene extracted s-SWNT deposited on such resonators exhibit sharp emission peaks, due to interaction with the cavity modes of the microring resonators. Ring resonators with radius of 5 {\\mu}m and 10 {\\mu}m were used, reaching quality factors up to 4000 in emission. These are among the highest values reported for carbon nanotubes coupled with an integrated cavity on silicon platform, which open up the possibility to build s-SWNT based efficient light source on silicon.

  4. TIME-RESOLVED PHOTOLUMINESCENCE OF SINTERED ZnO CERAMICS

    Institute of Scientific and Technical Information of China (English)

    WEN XIAO-MING(文小明); N.OHNO; ZHANG ZHONG-MING(张中明)

    2001-01-01

    The time-resolved photoluminescence (TRPL) of sintered ZnO ceramics was measured at low temperatures. A broad luminescence band was observed in the visible region. The TRPL experiment shows that photolurninescence decay behaviour can be depicted as t-π(r). The decay rate n(r) and lifetime are wavelength dependent, and the former varies exponentially with wavelength. The power-lowering behaviour of the luminescence intensity indicates that the luminescence band originates from the recombination of donor-acceptor pairs.

  5. Photoluminescence of a Te4+ center in zinc borate glass.

    Science.gov (United States)

    Masai, Hirokazu; Yamada, Yasuhiro; Okumura, Shun; Kanemitsu, Yoshihiko; Yoko, Toshinobu

    2013-10-01

    Photoluminescent (PL) properties related to Te(4+) species in zinc borate glasses are examined. Broad emission was observed by the excitation of the PL excitation peak of Te(4+) present at the optical absorption edge. The emission intensity of Te(4+) in 5TeO(2)-50ZnO-45B(2)O(3) glass was thermally quenched in a temperature region over 100 K, suggesting that concentration quenching preferentially occurred. The lifetime of the emission was approximately 2.5 μs, which is characteristic of relaxation from the triplet excitation state of an ns(2)-type center. PMID:24081051

  6. Optical characterization of semiconductors infrared, Raman, and photoluminescence spectroscopy

    CERN Document Server

    Perkowitz, Sidney

    1993-01-01

    This is the first book to explain, illustrate, and compare the most widely used methods in optics: photoluminescence, infrared spectroscopy, and Raman scattering. Written with non-experts in mind, the book develops the background needed to understand the why and how of each technique, but does not require special knowledge of semiconductors or optics. Each method is illustrated with numerous case studies. Practical information drawn from the authors experience is given to help establish optical facilities, including commercial sources for equipment, and experimental details. For industrial sci

  7. Photoluminescence and X-ray Diffraction of Distributed Bragg Reflector

    Institute of Scientific and Technical Information of China (English)

    LI Lin; LI Yong-da; LIU Wen-li; LU Bin; JU Guo-xian; ZHANG Yong-ming; HAO Yong-qin; SU Wei; ZHONG Jing-chang

    2004-01-01

    Spectral and structural characteristics of distributed Bragg reflector (DBR) in vertical-cavity surface-emitting lasers were studied with photoluminescence and double- crystal X- ray diffraction measurement. The expected high quality epitaxial DBR structure was verified. In the X- ray double- crystal rocking curves of DBR the zeroth- order peak, the first and second order satellite peaks were measured.Splitting of diffraction peak appeared in the rocking curves was analyzed. The effects of introduced deep energy levels on the structural perfection and optical properties were discussed.

  8. Measurement of Photoluminescence of Cu2O at 2 K

    Institute of Scientific and Technical Information of China (English)

    ZHOU Yu; ZHANG Gui-Zhong; XIANG Wang-Hua; KETTERSON J. B.

    2006-01-01

    @@ We present our measured photoluminescence of the quadrupolar transitions of the yellow series excitons of cuprous oxide at 2 K. By tuning the excitation energy in the two-photon quadrupolar absorption scheme of Cu2O, it is found that the band-gap value associated with this optical process can be characterized by a sharp resonance at 2.036eV at cryogenic temperature. This energy value is helpful to guide a proper excitation for creating cold excitonic gas in this crystal.

  9. Tuning Photoluminescence Response by Electric Field in Electrically Soft Ferroelectrics

    Science.gov (United States)

    Khatua, Dipak Kumar; Kalaskar, Abhijeet; Ranjan, Rajeev

    2016-03-01

    We show that an electrically soft ferroelectric host can be used to tune the photoluminescence (PL) response of rare-earth emitter ions by external electric field. The proof of this concept is demonstrated by changing the PL response of the Eu3 + ion by electric field on a model system Eu-doped 0.94 (Na1 /2Bi1 /2TiO3)-0.06 (BaTiO3) . We also show that new channels of radiative transitions, forbidden otherwise, open up due to positional disorder in the system, which can as well be tuned by electric field.

  10. The photoluminescence of Co-Al-layered double hydroxide

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    We report a new optical behaviour of pure Co-Al-layered double hydroxide (LDH). It was found that the Co-Al-LDH sample could emit fluorescence without any fluorescent substances intercalated. Its excitation spectrum shows a maximum peak near the wavelength 370 nm, the maximum emission peak appears at 430 nm and the photoluminescence colour of the Co-Al-LDH sample is blue. This new optical property will be expected to extend the potential applications of LDHs in optical materials field.

  11. Highly Photoluminescent and Stable Aqueous ZnS Quantum Dots

    OpenAIRE

    Li, Hui; Shih, Wan Y.; Shih, Wei-Heng

    2010-01-01

    We report an all-aqueous synthesis of highly photoluminescent and stable ZnS quantum dots (QDs) with water as the medium, i.e. first synthesizing ZnS QDs with 3-mercaptopropionic acid (MPA) as the capping molecule, followed by replacing some of MPA with (3-mercaptopropyl) trimethoxysilane (MPS). The resultant MPS-replaced ZnS QDs were about 5 nm in size with a cubic zinc blende crystalline structure, and had both MPA and MPS on the surface as confirmed by the Fourier Transform Infrared (FTIR)...

  12. Temperature-dependent photoluminescence of surface-engineered silicon nanocrystals

    Science.gov (United States)

    Mitra, Somak; Švrček, Vladimir; Macias-Montero, Manual; Velusamy, Tamilselvan; Mariotti, Davide

    2016-06-01

    In this work we report on temperature-dependent photoluminescence measurements (15–300 K), which have allowed probing radiative transitions and understanding of the appearance of various transitions. We further demonstrate that transitions associated with oxide in SiNCs show characteristic vibronic peaks that vary with surface characteristics. In particular we study differences and similarities between silicon nanocrystals (SiNCs) derived from porous silicon and SiNCs that were surface-treated using a radio-frequency (RF) microplasma system.

  13. Strong photoluminescence emission from resonant Fibonacci quantum wells.

    Science.gov (United States)

    Chang, C H; Chen, C H; Hsueh, W J

    2013-06-17

    Strong photoluminescence (PL) emission from a resonant Fibonacci quantum well (FQW) is demonstrated. The maximum PL intensity in the FQW is significantly stronger than that in a periodic QW under the Bragg or anti-Bragg conditions. Moreover, the peaks of the squared electric field in the FQW are located very near each of the QWs. The optimal PL spectrum in the FQW has an asymmetrical form rather than the symmetrical one in the periodic case. The maximum PL intensity and the corresponding thickness filling factor in the FQW become greater with increasing generation order. PMID:23787654

  14. Photoluminescence efficiency in AlGaN quantum wells

    Energy Technology Data Exchange (ETDEWEB)

    Tamulaitis, G.; Mickevičius, J. [Institute of Applied Research and Semiconductor Physics Department, Vilnius University, Sauletekio av. 9-III, Vilnius LT-10222 (Lithuania); Jurkevičius, J., E-mail: jonas.jurkevicius@ff.vu.lt [Institute of Applied Research and Semiconductor Physics Department, Vilnius University, Sauletekio av. 9-III, Vilnius LT-10222 (Lithuania); Shur, M.S. [Department of ECE and CIE, Rensselaer Polytechnic Institute (United States); Shatalov, M.; Yang, J.; Gaska, R. [Sensor Electronic Technology, Inc. (United States)

    2014-11-15

    Photoluminescence spectroscopy of AlGaN/AlGaN multiple quantum wells under quasi-steady-state conditions in the temperature range from 8 to 300 K revealed a strong dependence of droop onset threshold on temperature that was explained by the influence of carrier delocalization. The delocalization at room temperature results predominantly in enhancement of bimolecular radiative recombination, while being favorable for enhancement of nonradiative recombination at low temperatures. Studies of stimulated emission confirmed the strong influence of carrier localization on droop.

  15. Photoluminescence intermittency of semiconductor quantum dots in dielectric environments

    Energy Technology Data Exchange (ETDEWEB)

    Isaac, A.

    2006-08-11

    The experimental studies presented in this thesis deal with the photoluminescence intermittency of semiconductor quantum dots in different dielectric environments. Detailed analysis of intermittency statistics from single capped CdSe/ZnS, uncapped CdSe and water dispersed CdSe/ZnS QDs in different matrices provide experimental evidence for the model of photoionization with a charge ejected into the surrounding matrix as the source of PL intermittency phenomenon. We propose a self-trapping model to explain the increase of dark state lifetimes with the dielectric constant of the matrix. (orig.)

  16. Enhancing and redirecting carbon nanotube photoluminescence by an optical antenna.

    Science.gov (United States)

    Böhmler, Miriam; Hartmann, Nicolai; Georgi, Carsten; Hennrich, Frank; Green, Alexander A; Hersam, Mark C; Hartschuh, Achim

    2010-08-01

    We observe the angular radiation pattern of single carbon nanotubes' photoluminescence in the back focal plane of a microscope objective and show that the emitting nanotube can be described by a single in-plane point dipole. The near-field interaction between a nanotube and an optical antenna modifies the radiation pattern that is now dominated by the antenna characteristics. We quantify the antenna induced excitation and radiation enhancement and show that the radiative rate enhancement is connected to a directional redistribution of the emission. PMID:20721031

  17. Compared in vivo toxicity in mice of lung delivered biodegradable and non-biodegradable nanoparticles.

    Science.gov (United States)

    Aragao-Santiago, Letícia; Hillaireau, Hervé; Grabowski, Nadège; Mura, Simona; Nascimento, Thais L; Dufort, Sandrine; Coll, Jean-Luc; Tsapis, Nicolas; Fattal, Elias

    2016-01-01

    To design nanoparticle (NP)-based drug delivery systems for pulmonary administration, biodegradable materials are considered safe, but their potential toxicity is poorly explored. We here explore the lung toxicity in mice of biodegradable nanoparticles (NPs) and compare it to the toxicity of non-biodegradable ones. NP formulations of poly(d,l-lactide-co-glycolide) (PLGA) coated with chitosan (CS), poloxamer 188 (PF68) or poly(vinyl alcohol) (PVA), which renders 200 nm NPs of positive, negative or neutral surface charge respectively, were analyzed for their biodistribution by in vivo fluorescence imaging and their inflammatory potential after single lung nebulization in mice. After exposure, analysis of bronchoalveolar lavage (BAL) cell population, protein secretion and cytokine release as well as lung histology were carried out. The inflammatory response was compared to the one induced by non-biodegradable counterparts, namely, TiO2 of rutile and anatase crystal form and polystyrene (PS). PLGA NPs were mostly present in mice lungs, with little passage to other organs. An increase in neutrophil recruitment was observed in mice exposed to PS NPs 24 h after nebulization, which declined at 48 h. This result was supported by an increase in interleukin (IL)-6 and tumor necrosis factor α (TNFα) in BAL supernatant at 24 h. TiO2 anatase NPs were still present in lung cells 48 h after nebulization and induced the expression of pro-inflammatory cytokines and the recruitment of polymorphonuclear cells to BAL. In contrast, regardless of their surface charge, PLGA NPs did not induce significant changes in the inflammation markers analyzed. In conclusion, these results point out to a safe use of PLGA NPs regardless of their surface coating compared to non-biodegradable ones.

  18. Hydrocarbons biodegradation in unsaturated porous medium; Biodegradation des hydrocarbures en milieu poreux insature

    Energy Technology Data Exchange (ETDEWEB)

    Gautier, C

    2007-12-15

    Biological processes are expected to play an important role in the degradation of petroleum hydrocarbons in contaminated soils. However, factors influencing the kinetics of biodegradation are still not well known, especially in the unsaturated zone. To address these biodegradation questions in the unsaturated zone an innovative experimental set up based on a physical column model was developed. This experimental set up appeared to be an excellent tool for elaboration of a structured porous medium, with well defined porous network and adjusted water/oil saturations. Homogeneous repartition of both liquid phases (i.e., aqueous and non aqueous) in the soil pores, which also contain air, was achieved using ceramic membranes placed at the bottom of the soil column. Reproducible interfaces (and connectivity) are developed between gas, and both non mobile water and NAPL phases, depending on the above-defined characteristics of the porous media and on the partial saturations of these three phases (NAPL, water and gas). A respirometric apparatus was coupled to the column. Such experimental set up have been validated with hexadecane in dilution in an HMN phase. This approach allowed detailed information concerning n-hexadecane biodegradation, in aerobic condition, through the profile of the oxygen consumption rate. We have taken benefit of this technique, varying experimental conditions, to determine the main parameters influencing the biodegradation kinetics and compositional evolution of hydrocarbons, under steady state unsaturated conditions and with respect to aerobic metabolism. Impacts of the nitrogen quantity and of three different grain sizes have been examined. Biodegradation of petroleum cut, as diesel cut and middle distillate without aromatic fraction, were, also studied. (author)

  19. Biodegradable elastomers for biomedical applications and regenerative medicine

    NARCIS (Netherlands)

    Bat, Erhan; Zhang, Zheng; Feijen, Jan; Grijpma, Dirk W.; Poot, Andre A.

    2014-01-01

    Synthetic biodegradable polymers are of great value for the preparation of implants that are required to reside only temporarily in the body. The use of biodegradable polymers obviates the need for a second surgery to remove the implant, which is the case when a nondegradable implant is used. After

  20. Biodegradation of clofibric acid and identification of its metabolites

    Energy Technology Data Exchange (ETDEWEB)

    Salgado, R. [REQUIMTE/CQFB, Chemistry Department, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); ESTS-IPS, Escola Superior de Tecnologia de Setubal do Instituto Politecnico de Setubal, Rua Vale de Chaves, Campus do IPS, Estefanilha, 2910-761 Setubal (Portugal); Oehmen, A. [REQUIMTE/CQFB, Chemistry Department, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Carvalho, G. [REQUIMTE/CQFB, Chemistry Department, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Instituto de Biologia Experimental e Tecnologica (IBET), Av. da Republica (EAN), 2784-505 Oeiras (Portugal); Noronha, J.P. [REQUIMTE/CQFB, Chemistry Department, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Reis, M.A.M., E-mail: amr@fct.unl.pt [REQUIMTE/CQFB, Chemistry Department, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal)

    2012-11-30

    Graphical abstract: Metabolites produced during clofibric acid biodegradation. Highlights: Black-Right-Pointing-Pointer Clofibric acid is biodegradable. Black-Right-Pointing-Pointer Mainly heterotrophic bacteria degraded the clofibric acid. Black-Right-Pointing-Pointer Metabolites of clofibric acid biodegradation were identified. Black-Right-Pointing-Pointer The metabolic pathway of clofibric acid biodegradation is proposed. - Abstract: Clofibric acid (CLF) is the pharmaceutically active metabolite of lipid regulators clofibrate, etofibrate and etofyllinclofibrate, and it is considered both environmentally persistent and refractory. This work studied the biotransformation of CLF in aerobic sequencing batch reactors (SBRs) with mixed microbial cultures, monitoring the efficiency of biotransformation of CLF and the production of metabolites. The maximum removal achieved was 51% biodegradation (initial CLF concentration = 2 mg L{sup -1}), where adsorption and abiotic removal mechanisms were shown to be negligible, showing that CLF is indeed biodegradable. Tests showed that the observed CLF biodegradation was mainly carried out by heterotrophic bacteria. Three main metabolites were identified, including {alpha}-hydroxyisobutyric acid, lactic acid and 4-chlorophenol. The latter is known to exhibit higher toxicity than the parent compound, but it did not accumulate in the SBRs. {alpha}-Hydroxyisobutyric acid and lactic acid accumulated for a period, where nitrite accumulation may have been responsible for inhibiting their degradation. A metabolic pathway for the biodegradation of CLF is proposed in this study.

  1. Methods for Evaluating the Biodegradability of Environmentally Degradable Polymers

    NARCIS (Netherlands)

    Zee, van der M.

    2014-01-01

    This chapter presents an overview of the current knowledge on experimental methods for monitoring the biodegradability of polymeric materials. The focus is, in particular, on the biodegradation of materials under environmental conditions. Examples of in vivo degradation of polymers used in biomedica

  2. A Sensitive and Biodegradable Pressure Sensor Array for Cardiovascular Monitoring.

    Science.gov (United States)

    Boutry, Clementine M; Nguyen, Amanda; Lawal, Qudus Omotayo; Chortos, Alex; Rondeau-Gagné, Simon; Bao, Zhenan

    2015-11-18

    An array of highly sensitive pressure sensors entirely made of biodegradable materials is presented, designed as a single-use flexible patch for application in cardiovascular monitoring. The high sensitivity in combination with fast response time is unprecedented when compared to recent reports on biodegradable pressure sensors (sensitivity three orders of magnitude higher), as illustrated by pulse wave velocity measurements, toward hypertension detection.

  3. Nanocomposites with biodegradable polymers synthesis properties and future perspectives

    CERN Document Server

    2011-01-01

    Polymers are used in practically every facet of daily life. Most polymers come from fossil fuels and are not biodegradable, causing long-term environmental hazards. Biodegradable polymers provide an alternative class of materials. Composites of such polymers have high potential within a wide spectrum of applications.

  4. The use of biodegradable mulch films in muskmelon crop production

    Directory of Open Access Journals (Sweden)

    Artur Saraiva

    2012-10-01

    Full Text Available Due to the large amount of mulch films used in agricultural crops and to all the environmental problems related with their disposal, the biodegradable mulch films seems to be the best solution for replacing the conventional polyethylene mulches. The main goal of this work was to evaluate and compare the performance of biodegradable mulch films with the conventional polyethylene ones in muskmelon culture during two years. Beyond fruit productivity and quality, the impact of each plastic in the soil moisture and temperature were also assessed. Taking into account that there are no reported biodegradation studies realized in Portugal, it was also important to verify the biodegradability of this new mulch films under the Portuguese soil conditions. The biodegradable mulch films did not show significant differences in fruit productivity and quality. The biodegradation rate of the mulches tested was not as high as would be expected. From the overall results obtained, biodegradable mulch films appear to be a good solution for the replacement of the conventional polyethylene mulches, however the Research and Development should continue to be done ton improve their biodegradation rate.

  5. Critical evaluation of biodegradable polymers used in nanodrugs

    Directory of Open Access Journals (Sweden)

    Marin E

    2013-08-01

    Full Text Available Edgar Marin,1–3 Maria Isabel Briceño,2 Catherina Caballero-George11Unit of Pharmacology, Center of Biodiversity and Drug Discovery, Institute of Scientific Research and High Technology Services, 2Nano Dispersions Technology, Panama, Republic of Panama; 3Department of Biotechnology, Archaria Nagarjuna University, Guntur, IndiaAbstract: Use of biodegradable polymers for biomedical applications has increased in recent decades due to their biocompatibility, biodegradability, flexibility, and minimal side effects. Applications of these materials include creation of skin, blood vessels, cartilage scaffolds, and nanosystems for drug delivery. These biodegradable polymeric nanoparticles enhance properties such as bioavailability and stability, and provide controlled release of bioactive compounds. This review evaluates the classification, synthesis, degradation mechanisms, and biological applications of the biodegradable polymers currently being studied as drug delivery carriers. In addition, the use of nanosystems to solve current drug delivery problems are reviewed.Keywords: biodegradable polymers, nanoparticles, drug delivery, cellular uptake, biomedical applications

  6. [Progress on biodegradation of polylactic acid--a review].

    Science.gov (United States)

    Li, Fan; Wang, Sha; Liu, Weifeng; Chen, Guanjun

    2008-02-01

    Polylactic acid is a high molecular-weight polyester made from renewable resources such as corn or starch. It is a promising biodegradable plastic due to its mechanical properties, biocompatibility and biodegradability. To achieve natural recycling of polylactic acid, relative microorganisms and the underlying mechanisms in the biodegradation has become an important issue in biodegradable materials. Up to date, most isolated microbes capable of degrading polylactic acid belong to actinomycetes. Proteases secreted by these microorganisms are responsible for the degradation. However, subtle differences exist between these polylactic acid degrading enzymes and typical proteases with respect to substrate binding and catalysis. Amino acids relative to catalysis are postulated to be highly plastic allowing their catalytic hydrolysis of polylactic acid. In this paper we reviewed current studies on biodegradation of polylactic acid concerning its microbial, enzymatic reactions and the possible mechanisms. We also discussed the probability of biologically recycling PLA by applying highly efficient strains and enzymes. PMID:18438013

  7. Experimental studies of biodegradation of asphalt by microorganisms

    International Nuclear Information System (INIS)

    On the geological disposal system of the radioactive wastes, the activities of the microorganisms that could degrade the asphalt might be significant for the assessment of the system performance. As the main effects of the biodegradation of the asphalt, the fluctuation of leaching behavior of the nuclides included in asphalt waste has been indicated. In this study, the asphalt biodegradation test was carried out. The microorganism of which asphalt degradation ability was comparatively higher under aerobic condition and anaerobic condition was used. The asphalt biodegradation rate was calculated and it was evaluated whether the asphalt biodegradation in this system could occur. The results show that the asphalt biodegradation rate under anaerobic and high alkali condition will be 300 times lower than under aerobic and neutral pH. (author)

  8. Biodegradation of acetanilide herbicides acetochlor and butachlor in soil

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The biodegradation of two acetanilide herbicides,acetochlor and butachlor in soil after other environmental organicmatters addition were measured during 35 days laboratoryincubations. The herbicides were applied to soil alone, soil-SDBS(sodium dodecylbenzene sulfonate) mixtures and soil-HA (humic acid)mixtures. Herbicide biodegradation kinetics were compared in thedifferent treatment. Biodegradation products of herbicides in soilalone samples were identified by GC/MS at the end of incubation.Addition of SDBS and HA to soil decreased acetochlorbiodegradation, but increased butachlor biodegradation. Thebiodegradation half-life of acetochlor and butachlor in soil alone,soil-SDBS mixtures and soil-HA mixtures were 4.6d, 6.1d, 5.4d, and5.3d, 4.9d, and 5.3d respectively. The biodegradation products werehydroxyacetochlor and 2-methyl-6-ethylaniline for acetochlor, andhydroxybutachlor and 2,6-diethylaniline for butachlor.

  9. Evaluation of Artificial Intelligence Based Models for Chemical Biodegradability Prediction

    Directory of Open Access Journals (Sweden)

    Aleksandar Sabljic

    2004-12-01

    Full Text Available This study presents a review of biodegradability modeling efforts including a detailed assessment of two models developed using an artificial intelligence based methodology. Validation results for these models using an independent, quality reviewed database, demonstrate that the models perform well when compared to another commonly used biodegradability model, against the same data. The ability of models induced by an artificial intelligence methodology to accommodate complex interactions in detailed systems, and the demonstrated reliability of the approach evaluated by this study, indicate that the methodology may have application in broadening the scope of biodegradability models. Given adequate data for biodegradability of chemicals under environmental conditions, this may allow for the development of future models that include such things as surface interface impacts on biodegradability for example.

  10. The influence of antioxidant and post-synthetic treatment on the properties of biodegradable poly(butylene succinates modified with poly(propylene oxide

    Directory of Open Access Journals (Sweden)

    DRAGANA PEPIC

    2007-12-01

    Full Text Available Novel poly(ester–ethers based on poly(butylene succinate (PBS as the hard segments and 30 mass % of poly(propylene oxide (PPO as the soft segments were synthesized with varying amount of the antioxidant (N,N'-diphenyl-p-phenylenediamine, DPPD. The influences of the addition of DPPD and the impact of post-synthetic treatment by precipitation on the molecular structure, thermal and physical properties, as well as on the storage stability of the biodegradable aliphatic copolyesters, were investigated. The structure and composition of the copolymers were determined by means of 1H-NMR spectroscopy. The molecular weight and polydispersity of the poly(ester–ethers were evaluated from solution viscosity and GPC measurements. The thermal properties and stability were evaluated, respecttively, by means of DSC and non-isothermal thermogravimetry in an inert nitrogen atmosphere. The biodegradability potential of the polymers was studied in hydrolytic and enzymatic degradation tests with Candida cylindracea lipase by monitoring the weight loss of polymer films after incubation. The weight losses of the samples increased with time and were in the range from 1 to 5 mass % after 4 weeks. GPC analysis confirmed that there were changes in the molecular weight of the copolyesters during both hydrolytic and enzymatic degradation tests, leading to the conclusion that the degradation mechanism of poly(butylenes succinate modified with PPO occurred through surface erosion and bulk degradation.

  11. Polymeric Biodegradable Stent Insertion in the Esophagus

    Directory of Open Access Journals (Sweden)

    Kai Yang

    2016-04-01

    Full Text Available Esophageal stent insertion has been used as a well-accepted and effective alternative to manage and improve the quality of life for patients diagnosed with esophageal diseases and disorders. Current stents are either permanent or temporary and are fabricated from either metal or plastic. The partially covered self-expanding metal stent (SEMS has a firm anchoring effect and prevent stent migration, however, the hyperplastic tissue reaction cause stent restenosis and make it difficult to remove. A fully covered SEMS and self-expanding plastic stent (SEPS reduced reactive hyperplasia but has a high migration rate. The main advantage that polymeric biodegradable stents (BDSs have over metal or plastic stents is that removal is not require and reduce the need for repeated stent insertion. But the slightly lower radial force of BDS may be its main shortcoming and a post-implant problem. Thus, strengthening support of BDS is a content of the research in the future. BDSs are often temporarily effective in esophageal stricture to relieve dysphagia. In the future, it can be expect that biodegradable drug-eluting stents (DES will be available to treat benign esophageal stricture, perforations or leaks with additional use as palliative modalities for treating malignant esophageal stricture, as the bridge to surgery or to maintain luminal patency during neoadjuvant chemoradiation.

  12. Tailoring the biodegradability of porous silicon nanoparticles.

    Science.gov (United States)

    Hon, Nick K; Shaposhnik, Zory; Diebold, Eric D; Tamanoi, Fuyuhiko; Jalali, Bahram

    2012-12-01

    Porous silicon nanoparticles (PSiNPs) are attractive carriers for targeted drug delivery in nanomedicine. For in vivo applications, the biodegradation property of PSiNPs provides a pathway for their safe clearance from the body. Particles sizes of 80-120 nm are of particular interest as they are important for cellular applications, such as drug delivery for cancer therapy, because these nanoparticles can take advantage of the enhanced permeability and retention effect to deliver drug preferentially to tumors with leaky vasculature, yet large enough to avoid renal clearance. However, the biodegradability rate of such particles is often too fast, which limits particle half-life and potentially reduces their in vivo delivery efficiency. In this work, we focus on the degradation of nanoscale particles and study the effect of both thermal oxidation and silica coating on the stability of PSiNPs in phosphate buffered saline solution (a close mimic of a basic biological fluid). Using thermal oxidation, the half-life of PSiNPs can be varied from 10 min up to 3 h. Using silica coating, the half-life can be extended further to 8 h. The particles produced using both these techniques can be functionalized using standard silica surface chemistries developed for applications in drug delivery.

  13. Optimization of low ring polycylic aromatic biodegradation

    Science.gov (United States)

    Othman, N.; Abdul-Talib, S.; Tay, C. C.

    2016-07-01

    Polycyclic aromatic hydrocarbons (PAHs) are recalcitrance and persistence that finally turn into problematic environmental contaminants. Microbial degradation is considered to be the primary mechanism of PAHs removal from the environment due to its organic criteria. This study is carried out to optimize degradation process of low ring PAHs. Bacteria used in this study was isolated from sludge collected from Kolej Mawar, Universiti Teknologi MARA, Shah Alam, Selangor. Working condition namely, substrate concentration, bacteria concentration, pH and temperature were optimized. PAHs in the liquid sample was extracted by using solid phase microextractio equipped with a 7 µm polydimethylsiloxane (PDMS) SPME fibr. Removal of PAHs were assessed by measuring PAHs concentration using GC-FID. Results from the optimization study of biodegradation indicated that maximum rate of PAHs removal occurred at 100 mgL-1 of PAHs, 10% bacteria concentration, pH 7.0 and 30°C. These working condition had proved the effectiveness of using bacteria in biodegradation process of PAHs.

  14. Characterization and aerobic biodegradation of selected monoterpenes

    Energy Technology Data Exchange (ETDEWEB)

    Misra, G.; Pavlostathis, S.G.; Li, J.; Purdue, E.M. [Georgia Institute of Technology, Atlanta, GA (United States)

    1996-12-31

    Monoterpenes are biogenic chemicals and occur in abundance in nature. Large-scale industrial use of these chemicals has recently been initiated in an attempt to replace halogenated solvents and chlorofluorocarbons which have been implicated in the stratospheric depletion of ozone. This study examined four hydrocarbon monoterpenes (d-limonene, {alpha}-pinene, {gamma}-terpinene, and terpinolene) and four alcohols (arbanol, linalool, plinol, and {alpha}-terpineol). Water solubility, vapor pressure, and octanol/water partition coefficients were estimated. Aerobic biodegradability tests were conducted in batch reactors by utilizing forest soil extract and enriched cultures as inoculum. The hydrophobic nature and high volatility of the hydrocarbons restricted the investigation to relatively low aqueous concentrations. Each monoterpene was analyzed with a gas chromatograph equipped with a flame ionization detector after extraction from the aqueous phase with isooctane. Terpene mineralization was tested by monitoring liquid-phase carbon, CO{sub 2} production and biomass growth. All four hydrocarbons and two alcohols readily degraded under aerobic conditions. Plinol resisted degradation in assays using inocula from diverse sources, while arbanol degraded very slowly. The intrinsic biokinetics coefficients for the degradation of d-limonene and {alpha}-terpineol were estimated by using cultures enriched with the respective monoterpenes. Monoterpene biodegradation followed Monod kinetics.

  15. A REVIEW ON BIODEGRADABLE STARCH BASED FILM

    Directory of Open Access Journals (Sweden)

    Hooman Molavi

    2015-04-01

    Full Text Available In recent years, biodegradable edible films have become very important in research related to food, due to their compatibility with the environment and their use in the food packaging industry. Various sources can be used in the production of biopolymers as biodegradable films that include polysaccharides, proteins and lipids. Among the various polysaccharides, starch due to its low price and its abundance in nature is of significant importance. Several factors affect the properties of starch films; such as the source which starch is obtained from, as well as the ratio of constituents of the starch. Starch films have advantages such as low thickness, flexibility and transparency though; there are some downsides to mention, such as the poor mechanical properties and water vapor permeability. Thus, using starch alone to produce the film will led to restrictions on its use. To improve the mechanical properties of starch films and also increases resistance against humidity, several methods can be used; including the starch modifying techniques such as cross linking of starch and combining starch with other natural polymers. Other methods such as the use of lipid in formulations of films to increase the resistance to moisture are possible, but lipids are susceptible to oxidation. Therefore, new approaches are based on the integration of different biopolymers in food packaging.

  16. Biodegradability of industrial textile wastewater - batch tests.

    Science.gov (United States)

    Paździor, Katarzyna; Klepacz-Smółka, Anna; Wrębiak, Julita; Liwarska-Bizukojć, Ewa; Ledakowicz, Stanisław

    2016-01-01

    Following new trends we applied oxygen uptake rate (OUR) tests as well as long-term tests (in two batch bioreactors systems) in order to assess the biodegradability of textile wastewater. Effluents coming from a dyeing factory were divided into two streams which differed in inorganic and organic contaminants loads. Usefulness of the stream division was proved. Biodegradation of the low-loaded stream led to over 97% reduction of biochemical oxygen demand (BOD5) together with 80% reduction of chemical oxygen demand (COD) and total organic carbon (TOC). Most of the controlled parameter values were below the levels allowed by legislation for influents to surface water, whereas the high-loaded stream was so contaminated with recalcitrant organic compounds that despite the reduction of BOD5 by over 95%, COD, TOC, total nitrogen and total phosphorus levels exceeded permissible values. OUR tests were aimed at determination of the following kinetic parameters: maximum specific growth rate (μMax), half-saturation constant, hydrolysis constant and decay coefficient for activated sludge biomass for both types of textile wastewater studied. The values of kinetic parameters will be applied in activated sludge models used for prediction and optimisation of biological treatment of textile wastewater. PMID:27642827

  17. Monitoring Biodegradation of Magnesium Implants with Sensors

    Science.gov (United States)

    Zhao, Daoli; Wang, Tingting; Guo, Xuefei; Kuhlmann, Julia; Doepke, Amos; Dong, Zhongyun; Shanov, Vesselin N.; Heineman, William R.

    2016-04-01

    Magnesium and its alloys exhibit properties such as high strength, light weight, and in vivo corrosion that make them promising candidates for the development of biodegradable metallic implant materials for bone repair, stents and other medical applications. Sensors have been used to monitor the corrosion of magnesium and its alloys by measuring the concentrations of the following corrosion products: magnesium ions, hydroxyl ions and hydrogen gas. The corrosion characterization system with home-made capillary pH and Mg2+ microsensors has been developed for real-time detection of magnesium corrosion in vitro. A hydrogen gas sensor was used to monitor the corrosion of magnesium by measuring the concentration of the hydrogen gas reaction product in vivo. The high permeability of hydrogen through skin allows transdermal monitoring of the biodegradation of a magnesium alloy implanted beneath the skin by detecting hydrogen gas at the skin surface. The sensor was used to map hydrogen concentration in the vicinity of an implanted magnesium alloy.

  18. Modification of Biodegradable Polyesters Using Electron Beam

    International Nuclear Information System (INIS)

    Poly(4-Hydroxybutyrate) P4HB, Poly(butylene succinate-co-adipate) PBSA and Poly(ε-caprolactone) PCL were electron beam (EB)-irradiated. Poly(4-Hydroxybutyrate) was irradiated without any polyfunctional monomers (PFM). While PBSA and PCL were irradiated in the presence of polyfunctional monomers such as Trimethallyl isocyanurate (TMAIC), Polyethyleneglycol dimethacrylate (2G, 4G), Trimethylolpropane trimethacrylate (TMPT) and Tetramethylolmethane tetraacrylate (A-TMMT) at ambient temperature. Aim of the study is to improve the properties of biodegradable polyester. It was pointed out that crosslinking yield of P4HB (6.39% gel) was formed at dose of 90 kGy irradiated in vacuum conditions. Radiation degradation promoted, when P4HB was irradiated in air. The optimum crosslinking yield of PCL and PBSA respectively, were formed in the presence of 1% TMAIC at dose of 50 kGy. The biodegradability of the crosslinked PBSA evaluated by soil burial test is slightly retarded by increasing crosslinking yields. (author)

  19. Immunological Response to Biodegradable Magnesium Implants

    Science.gov (United States)

    Pichler, Karin; Fischerauer, Stefan; Ferlic, Peter; Martinelli, Elisabeth; Brezinsek, Hans-Peter; Uggowitzer, Peter J.; Löffler, Jörg F.; Weinberg, Annelie-Martina

    2014-04-01

    The use of biodegradable magnesium implants in pediatric trauma surgery would render surgical interventions for implant removal after tissue healing unnecessary, thereby preventing stress to the children and reducing therapy costs. In this study, we report on the immunological response to biodegradable magnesium implants—as an important aspect in evaluating biocompatibility—tested in a growing rat model. The focus of this study was to investigate the response of the innate immune system to either fast or slow degrading magnesium pins, which were implanted into the femoral bones of 5-week-old rats. The main alloying element of the fast-degrading alloy (ZX50) was Zn, while it was Y in the slow-degrading implant (WZ21). Our results demonstrate that degrading magnesium implants beneficially influence the immune system, especially in the first postoperative weeks but also during tissue healing and early bone remodeling. However, rodents with WZ21 pins showed a slightly decreased phagocytic ability during bone remodeling when the degradation rate reached its maximum. This may be due to the high release rate of the rare earth-element yttrium, which is potentially toxic. From our results we conclude that magnesium implants have a beneficial effect on the innate immune system but that there are some concerns regarding the use of yttrium-alloyed magnesium implants, especially in pediatric patients.

  20. Near-unity photoluminescence quantum yield in MoS₂.

    Science.gov (United States)

    Amani, Matin; Lien, Der-Hsien; Kiriya, Daisuke; Xiao, Jun; Azcatl, Angelica; Noh, Jiyoung; Madhvapathy, Surabhi R; Addou, Rafik; KC, Santosh; Dubey, Madan; Cho, Kyeongjae; Wallace, Robert M; Lee, Si-Chen; He, Jr-Hau; Ager, Joel W; Zhang, Xiang; Yablonovitch, Eli; Javey, Ali

    2015-11-27

    Two-dimensional (2D) transition metal dichalcogenides have emerged as a promising material system for optoelectronic applications, but their primary figure of merit, the room-temperature photoluminescence quantum yield (QY), is extremely low. The prototypical 2D material molybdenum disulfide (MoS2) is reported to have a maximum QY of 0.6%, which indicates a considerable defect density. Here we report on an air-stable, solution-based chemical treatment by an organic superacid, which uniformly enhances the photoluminescence and minority carrier lifetime of MoS2 monolayers by more than two orders of magnitude. The treatment eliminates defect-mediated nonradiative recombination, thus resulting in a final QY of more than 95%, with a longest-observed lifetime of 10.8 ± 0.6 nanoseconds. Our ability to obtain optoelectronic monolayers with near-perfect properties opens the door for the development of highly efficient light-emitting diodes, lasers, and solar cells based on 2D materials.

  1. Photoluminescence of 1,3-dimethyl pyrazoloquinoline derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Koscien, E. [1st Liceum, Sobieskiego 22, 42-700 Lubliniec (Poland); Gondek, E.; Pokladko, M. [Institute of Physics, Technical University of Krakow, Podhorazych 1, 30-084 Krakow (Poland); Jarosz, B. [Department of Chemistry, Hugon Kollotaj Agricultural University, Al. Mickiewicza 24/28, 30-059 Krakow (Poland); Vlokh, R.O. [Institute of Physical Optics, Dragomanova 23, 79005 Lviv (Ukraine); Kityk, A.V. [Department of Electrical Engineering, Czestochowa University of Technology, Al. Armii Krajowej 17, 42-200 Czestochowa (Poland)], E-mail: kityk@ap.univie.ac.at

    2009-04-15

    This paper presents absorption and photoluminescence of 6-F, 6-Br, 6-Cl, 7-TFM and 6-COOEt derivatives of 1,3-dimethyl-1H-Pyrazolo[3,4-b]quinoline (DMPQ). The measured absorption and emission spectra are compared with the quantum chemical calculations performed by means of the semi-empirical methods (AM1 or PM3) that are applied either to the equilibrium conformations in vacuo (T = 0 K) or combined with the molecular dynamics simulations (T = 300 K). The spectra calculated by the AM1 method appear to be for all dyes in practically excellent agreement with the measured ones. In particular, the position of the first absorption band is obtained with the accuracy up to a few nanometers, whereas the calculated photoluminescence spectra predict the positions of the emission maxima for a gas phase with the accuracy up to 10-18 nm. The photoemission spectra of DMPQ dyes are considerably less solvatochromic comparing to phenyl-containing pyrazoloquinoline derivatives. According to the quantum chemical analysis the reason for such behaviour lies in a local character of the electronic transitions of DMPQ dyes which are characterized by a relatively small difference between the excited state and ground state dipole moments. Importantly that the rotational dynamics of both methyl subunits does not change this situation.

  2. Photoluminescence of indium-rich copper indium sulfide quantum dots

    International Nuclear Information System (INIS)

    The enhanced photoluminescence (PL) for In-rich copper indium sulfide quantum dots (CIS QDs) was observed. The conduction electron-Cu vacancy recombination and the donor–acceptor pair (DAP) defect recombination were considered to exist in CIS QDs at the same time. The temperature-dependent PL study showed that the emission of these QDs might be mainly originated from the recombination between electrons in the quantized conduction band and holes in the copper vacancy acceptor when x was 0.500 (CuxIn1−xS). However, the temperature coefficient of PL peak position decreased when x was 0.237. That meant the DAP recombination increased in the In-rich CIS QDs. - Highlights: • The enhanced photoluminescence (PL) for In-rich CuInS2 QDs with [Cu]/[In] molar ratios of 0.31. • The conduction electron-Cu vacancy recombination and DAP were considered to exist and the temperature-independent DAP recombination was enhanced in the In-rich CuInS2 QDs

  3. Photoluminescence and Photonics: from miniaturised light sources to radiation detectors

    International Nuclear Information System (INIS)

    Photonics is the science of the harnessing of light. Photonics encompasses the generation of light, the detection of light, the management of light through guidance, manipulation, and amplification. Luminescence phenomena are widely used in solid state light sources and radiation detectors based on point defects in insulators. Among them, 2 ed F3+ aggregate colour centres are induced in lithium fluoride (LiF) by various kinds of ionizing radiation and are laser active in the visible spectral region. They have been studied and successfully used at Frascati ENEA Research Centre for realizing prototypes of both miniaturized light sources, in the form of waveguides and vertical optical micro cavities for integrated optics, and of novel X-ray imaging detectors, based on the optical reading of photoluminescence of the locally induced defects. The highest intrinsic spatial resolution on a wide field of view and their versatility, achieved by the growth of LiF thin films by thermal evaporation, allow using such detectors in the frameworks of nano photonics, life science and energy. Recently, they have been also used in the advanced diagnostics of proton beams, with promising results in imaging and dosimetry based on photoluminescence

  4. Application of Topology Index in Aliphatic Aldehydes,Fatty Amines and Aliphatic Hydrocarbons Boiling Point%拓扑指数在脂肪醛、脂肪胺及脂肪烃沸点中的应用

    Institute of Scientific and Technical Information of China (English)

    周长会; 吴启勋; 侯庆高; 高宴梓; 李洪囡; 张瑞

    2013-01-01

    Two matrices and a topological index W were defined,then,topological index W was put into nonlinear regression with the boiling point of aliphatic aldehydes, fatty amines and aliphatic hydrocarbons, respectively, and with good results,the correlation coefficient reaches a good level. The established topological index and two kinds of matrix are easy and convenient to use, which can quickly predict the boiling point of the molecule.%定义了两种矩阵和一种拓扑指数W,将拓扑指数W分别与脂肪醛、脂肪胺及脂肪烃的沸点进行非线性回归,取得了较好的结果,相关性系数达到了良好级别.建立的拓扑指数和两种矩阵简洁方便,可以快速预测分子的沸点.

  5. Different aliphatic dicarboxylates affected assemble of new coordination polymers constructed from flexible-rigid mixed ligands

    International Nuclear Information System (INIS)

    In this article, seven coordination polymers: [Cd(C5H6O4)(C10H8N2)]n (1), [Zn(C5H6O4)(C10H8N2)]n (2), [Cd(C6H8O4)(C10H8N2)]n (3), {[Mn(C10H8N2)(H2O)4] (C4H4O4).4H2O}n (4), [Mn5(C4H4O4)4(O)]n (5), [Cd(C4H4O4)(C10H8N2)(H2O)]n (6) and [Zn(C6H6O4)(C12H8N2)(H2O)]n (7) were synthesized and characterized by single-crystallographic X-ray diffraction. Compounds 1 and 2 are two-dimensional layers connected by glutarate anions and 4,4'-bpy. Unlike compounds 1 and 2, compound 3 is a two-fold interpenetration network. Compound 4 is a one-dimensional chain-like structure, which is further extended to two-dimensional supramolecular layer structure with hydrogen bond. During the synthesis of compound 4, to our surprise, we got compound 5; compound 5 is an interesting three-dimensional network composed of pentanuclear Mn(II) building units and succinate anions. Compound 6 is also a two-dimensional supramolecular layer structure composed of one-dimensional chain-like structure with hydrogen bonds and Π-Π interactions. Compound 7 is also a one-dimensional chain-like structure, which is further connected with the same kind of interaction to generate two-dimensional supramolecular layer structure. Furthermore, compounds 1 and 2 both exhibit fluorescent property at room temperature. - Graphical abstract: Seven complexes composed by 3D metal ions, aliphatic acid ligand and rigid bidentate nitrogen ligands: 4,4'-bpy, 2,2'-bpy and 1,10'-phen. With the change of the carbon number of the backbone of aliphatic dicarboxylate ligand, we can synthesize different complexes with various structures

  6. Seasonal variation of aliphatic amines in marine sub-micrometer particles at the Cape Verde islands

    Directory of Open Access Journals (Sweden)

    H. Herrmann

    2009-12-01

    Full Text Available Monomethylamine (MA, dimethylamine (DMA and diethylamine (DEA were detected at non-negligible concentrations in sub-micrometer particles at the Cap Verde Atmospheric Observatory (CVAO located on the island of São Vicente in Cape Verde during algal blooms in 2007. The concentrations of these amines in five stage impactor samples ranged from 0–30 pg m−3 for MA, 130–360 pg m−3 for DMA and 5–110 pg m−3 for DEA during the spring bloom in May 2007 and 2–520 pg m−3 for MA, 100–1400 pg m−3 for DMA and 90–760 pg m−3 for DEA during an unexpected winter algal bloom in December 2007. Anomalously high Saharan dust deposition and intensive ocean layer deepening were found at the Atmospheric Observatory and the associated Ocean Observatory during algal bloom periods. The highest amine concentrations in fine particles (impactor stage 2, 0.14–0.42 μm indicate that amines are likely taken up from the gas phase into the acidic sub-micrometer particles. The contribution of amines to the organic carbon (OC content ranged from 0.2–2.5% C in the winter months, indicating the importance of this class of compounds to the carbon cycle in the marine environment. Furthermore, aliphatic amines originating from marine biological sources likely contribute significantly to the nitrogen content in the marine atmosphere. The average contribution of the amines to the detected nitrogen species in sub-micrometer particles can be non-negligible, especially in the winter months (0.1% N–1.5% N in the sum of nitrate, ammonium and amines. This indicates that these smaller aliphatic amines can be important for the carbon and the nitrogen cycles in the remote marine environment.

  7. Green Aza-Michael Reaction of Aliphatic Amines to á,(a)-Unsaturated Compounds in Water

    Institute of Scientific and Technical Information of China (English)

    XU Li-Wen; XIA Chun-Gu

    2004-01-01

    The hydroamination of olefins is a long-standing goal for transition metal catalysis. And the metal-catalyzed addition of amines to carbon-carbon double bonds is an unsolved, synthetically important problem. Although recent advances have made using lanthanide and precious metal complexes, there are few excellent catalyst that display broad functional group tolerance and useful rates for an intermolecular aza-Michael addition. As such, the development of efficient synthetic methods leading to a-amino carbonyl compounds and derivatives has attracted much attention in organic synthesis. Although recent advances have made this route more attractive, development of cheaper, simpler, and more efficient metal catalyst is highly desirable. We also have been interested in developing a reaction that uses catalytic quantities of minimally toxic, readily available, economic reagent should greatly contribute to the creation of environmental benign processes.The recent interest in aqueous medium metal-mediated carbon-carbon and carbon-heteroatom and formations led to the contributors for such reactions. Furthermore, development of organic reactions in water will contribute to the progress of green and quasi-nature catalysis chemistry. Surprisingly however, there is few report on conjugate additions of amines to a,a-unsaturated carbonyl compounds in water.Herein, we report a new protocol that employs air stable copper salts as efficient catalyst in the aza-Michael reaction under mild reaction conditions. Advantages of the protocol include high-yielding reactions that can be conducted at ambient temperature; the use of readily available and stable copper salts as the catalyst, and the reaction was successfully performed in environmental benign solvent, water.Finally, we have utilized a variety of aliphatic amines successfully with different á,(a)-unsaturated compounds catalyzed by simple hydrophilic ionic liquid, bmimBF4 in water. Interestingly, all the aliphatic amines gave

  8. Studies of the physical, yield and failure behavior of aliphatic polyketones

    Science.gov (United States)

    Karttunen, Nicole Renee

    This thesis describes an investigation into the multiaxial yield and failure behavior of an aliphatic polyketone terpolymer. The behavior is studied as a function of: stress state, strain rate, temperature, and sample processing conditions. Results of this work include: elucidation of the behavior of a recently commercialized polymer, increased understanding of the effects listed above, insight into the effects of processing conditions on the morphology of the polyketone, and a description of yield strength of this material as a function of stress state, temperature, and strain rate. The first portion of work focuses on the behavior of a set of samples that are extruded under "common" processing conditions. Following this reference set of tests, the effect of testing this material at different temperatures is studied. A total of four different temperatures are examined. In addition, the effect of altering strain rate is examined. Testing is performed under pseudo-strain rate control at constant nominal octahedral shear strain rate for each failure envelope. A total of three different rates are studied. An extension of the first portion of work involves modeling the yield envelope. This is done by combining two approaches: continuum level and molecular level. The use of both methods allows the description of the yield envelope as a function of stress state, strain rate and temperature. The second portion of work involves the effects of processing conditions. For this work, additional samples are extruded with different shear and thermal histories than the "standard" material. One set of samples is processed with shear rates higher and lower than the standard. A second set is processed at higher and lower cooling rates than the standard. In order to understand the structural cause for changes in behavior with processing conditions, morphological characterization is performed on these samples. In particular, the effect on spherulitic structure is important. Residual

  9. Photoluminescence-based quality control for thin film absorber layers of photovoltaic devices

    Energy Technology Data Exchange (ETDEWEB)

    Repins, Ingrid L.; Kuciauskas, Darius

    2015-07-07

    A time-resolved photoluminescence-based system providing quality control during manufacture of thin film absorber layers for photovoltaic devices. The system includes a laser generating excitation beams and an optical fiber with an end used both for directing each excitation beam onto a thin film absorber layer and for collecting photoluminescence from the absorber layer. The system includes a processor determining a quality control parameter such as minority carrier lifetime of the thin film absorber layer based on the collected photoluminescence. In some implementations, the laser is a low power, pulsed diode laser having photon energy at least great enough to excite electron hole pairs in the thin film absorber layer. The scattered light may be filterable from the collected photoluminescence, and the system may include a dichroic beam splitter and a filter that transmit the photoluminescence and remove scattered laser light prior to delivery to a photodetector and a digital oscilloscope.

  10. Studying of the photoluminescence characteristics of Au(0)@Au(I)-thiolate core–shell nanoclusters

    International Nuclear Information System (INIS)

    The photoluminescence characteristics of Au(0)@Au(I)-thiolate Core–shell nanoclusters (Au-NCs), whose size is <2 nm, are investigated. We use the time-resolved single-photon counting technique and the transient absorption technique to distinguish the mechanism of the photoluminescence of Au-NCs. The dynamic spectral data show that the photoluminescence mechanism should be composed of the fluorescence and the phosphorescence. Meanwhile, Au-NCs have the aggregation induced photoluminescence enhancement property, which is attributed to the suppression of conversion from the singlet state to triplet state when they aggregated together. In addition, the photoluminescence characteristics of aggregated Au-NCs should be further improved through infiltrating them into photonic crystals

  11. Syntheses of Enantiopure Aliphatic Secondary Alcohols and Acetates by Bioresolution with Lipase B from Candida antarctica

    Directory of Open Access Journals (Sweden)

    Richele P. Severino

    2012-07-01

    Full Text Available The lipase B from Candida antarctica (Novozym 435®, CALB efficiently catalyzed the kinetic resolution of some aliphatic secondary alcohols: (±-4-methylpentan-2-ol (1, (±-5-methylhexan-2-ol (3, (±-octan-2-ol (4, (±-heptan-3-ol (5 and (±-oct-1-en-3-ol (6. The lipase showed excellent enantioselectivities in the transesterifications of racemic aliphatic secondary alcohols producing the enantiopure alcohols (>99% ee and acetates (>99% ee with good yields. Kinetic resolution of rac-alcohols was successfully achieved with CALB lipase using simple conditions, vinyl acetate as acylating agent, and hexane as non-polar solvent.

  12. Thermotropic liquid crystalline polyesters derived from bis-(4-hydroxybenzoyloxy)-2-methyl-1,4-benzene and aliphatic dicarboxylic acid chlorides

    Indian Academy of Sciences (India)

    Khudbudin Mulani; Mohasin Momin; Nitin Ganjave; Nayaku Chavan

    2015-09-01

    A series of thermotropic liquid crystalline polyesters derived from bis-(4-hydroxybenzoyloxy)-2-methyl-1,4-benzene (BHBOMB) and aliphatic dicarboxylic acid chlorides were investigated. All these polyesters were synthesized by interfacial polycondensation method and characterized by differential scanning calorimetry and wide-angle X-ray diffractometer. These polyesters consist of BHBOMB as a mesogenic diol and aliphatic diacid chlorides were used as flexible spacers. The length of oligomethylene units in polymer was varied from the trimethylene to the dodecamethylene groups. The transition temperatures and thermodynamic properties were studied for all these polymers. All these polyesters were soluble in chlorinated solvents such as chloroform, dichloromethane, dichloroethane, etc. More importantly, all these polyesters exhibited very large mesophase stability.

  13. One- and two-dimensional divalent copper coordination polymers based on kinked organodiimine and long flexible aliphatic dicarboxylate ligands

    Science.gov (United States)

    Mallika Krishnan, Subhashree; Supkowski, Ronald M.; LaDuca, Robert L.

    2008-11-01

    Hydrothermal synthesis under acidic conditions has afforded a pair of divalent copper coordination polymers containing the kinked dipodal tethering organodiimine 4,4'-dipyridylamine (dpa) and flexible long-chain aliphatic dicarboxylate ligands. The new materials were characterized by single crystal X-ray structure determination, infrared spectroscopy, and thermogravimetric analysis. [CuCl(suberate) 0.5(dpa)] ( 1) manifests 1-D ladder-like motifs aggregated into 3-D through hydrogen bonding and copper-mediated supramolecular interactions. Extension of the aliphatic chain within the dicarboxylate ligand by one methylene unit resulted in {[Cu(azelate)(dpa)(H 2O)] · 3H 2O} ( 2), a (4,4) rhomboid grid 2-D coordination polymer encapsulating acyclic water molecule trimers.

  14. Are bioassays useful tools to assess redox processes and biodegradation?

    DEFF Research Database (Denmark)

    Albrechtsen, Hans-Jørgen; Pedersen, Philip Grinder; Ludvigsen, L.

    2002-01-01

    When evaluating potentials for natural attenuation, assessment of ongoing redox processes are important. Terminal electron accepting processes (TEAPs) such as denitrification, Fe(Ill), Mn(IV), and sulphate reduction and methane production have been assessed by several approaches including redox s...... of aromatic and chlorinated aliphatic compounds in landfill leachate plumes, and of pesticides in aquifers with various redox conditions....

  15. Secondary organic aerosol formation from primary aliphatic amines with NO3 radical

    Directory of Open Access Journals (Sweden)

    M. E. Erupe

    2008-07-01

    Full Text Available Primary aliphatic amines are an important class of nitrogen containing compounds found to be emitted from automobiles, waste treatment facilities and agricultural animal operations. A series of experiments conducted at the UC-Riverside/CE-CERT Environmental Chamber is presented in which oxidation of methylamine, ethylamine, propylamine, and butylamine with NO3 has been investigated. Very little aerosol formation is observed in the presence of O3 only. However, after addition of NO, and by extension NO3, large yields of aerosol mass loadings (~44% for butylamine are seen. Aerosol generated was determined to be organic in nature due to the small fraction of NO and NO2 in the total signal (<17% for all amines tested as detected by an aerosol mass spectrometer (AMS. We propose a reaction mechanism between carbonyl containing species and the parent amine leading to formation of particulate imine products. These findings can have significant impacts on rural communities and lead to elevated nighttime PM loadings, when significant levels on NO3 exist.

  16. Synthesis of Carbon Nanotubes of Few Walls Using Aliphatic Alcohols as a Carbon Source

    Directory of Open Access Journals (Sweden)

    Francisco Espinosa-Magaña

    2013-06-01

    Full Text Available Carbon nanotubes with single and few walls are highly appreciated for their technological applications, regardless of the limited availability due to their high production cost. In this paper we present an alternative process that can lead to lowering the manufacturing cost of CNTs of only few walls by means of the use of the spray pyrolysis technique. For this purpose, ferrocene is utilized as a catalyst and aliphatic alcohols (methanol, ethanol, propanol or butanol as the carbon source. The characterization of CNTs was performed by scanning electron microscopy (SEM and transmission electron microscopy (TEM. The study of the synthesized carbon nanotubes (CNTs show important differences in the number of layers that constitute the nanotubes, the diameter length, the quantity and the quality as a function of the number of carbons employed in the alcohol. The main interest of this study is to give the basis of an efficient synthesis process to produce CNTs of few walls for applications where small diameter is required.

  17. Aliphatic ketones from Ruta chalepensis (Rutaceae) induce paralysis on root knot nematodes.

    Science.gov (United States)

    Ntalli, Nikoletta G; Manconi, Francesca; Leonti, Marco; Maxia, Andrea; Caboni, Pierluigi

    2011-07-13

    This paper reports on the use of Ruta chalepensis L. extracts as a potential nematicide against root knot nematodes Meloidogyne incognita and Meloidogyne javanica . The essential oil (REO) and methanol extract (RME) of R. chalepensis were tested against second-stage juveniles, with REO inducing paralysis in both species (EC(50/1d) = 77.5 and 107.3 mg/L) and RME being selective for M. incognita (EC(50/1d) = 1001 mg/L). Chemical characterization of extracts was done by means of GC-MS and LC-MS, revealing mainly aliphatic ketones and coumarins, respectively. The first-ranking volatile nematicidal component in terms of individual activity against both species was 2-undecanone (EC(50) = 20.6 and 22.5 mg/L for M. incognita and M. javanica, respectively). This fact together with its high concentration in the most active extract found in this study, namely, REO (2926 mg/kg), categorizes 2-undecanone among the nematicidal principles of R. chalepensis. On the contrary, coumarins rutin and 8-methoxypsoralen were not found to be nematicidal at concentrations of ≤500 mg/L. Interestingly, M. incognita was found more sensitive than M. javanica.

  18. Sum frequency generation image reconstruction: aliphatic membrane under spherical cap geometry.

    Science.gov (United States)

    Volkov, Victor

    2014-10-01

    The article explores an opportunity to approach structural properties of phospholipid membranes using Sum Frequency Generation microscopy. To establish the principles of sum frequency generation image reconstruction in such systems, at first approach, we may adopt an idealistic spherical cap uniform assembly of hydrocarbon molecules. Quantum mechanical studies for decanoic acid (used here as a representative molecular system) provide necessary information on transition dipole moments and Raman tensors of the normal modes specific to methyl terminal - a typical moiety in aliphatic (and phospholipid) membranes. Relative degree of localization and frequencies of the normal modes of methyl terminals make nonlinearities of this moiety to be promising in structural analysis using Sum Frequency Generation imaging. Accordingly, the article describes derivations of relevant macroscopic nonlinearities and suggests a mapping procedure to translate amplitudes of the nonlinearities onto microscopy image plane according to geometry of spherical assembly, local molecular orientation, and optical geometry. Reconstructed images indicate a possibility to extract local curvature of bilayer envelopes of spherical character. This may have practical implications for structural extractions in membrane systems of practical relevance. PMID:25296798

  19. Sum frequency generation image reconstruction: Aliphatic membrane under spherical cap geometry

    Energy Technology Data Exchange (ETDEWEB)

    Volkov, Victor [Bereozovaya 2A, Konstantinovo, Moscow Region 140207 (Russian Federation)

    2014-10-07

    The article explores an opportunity to approach structural properties of phospholipid membranes using Sum Frequency Generation microscopy. To establish the principles of sum frequency generation image reconstruction in such systems, at first approach, we may adopt an idealistic spherical cap uniform assembly of hydrocarbon molecules. Quantum mechanical studies for decanoic acid (used here as a representative molecular system) provide necessary information on transition dipole moments and Raman tensors of the normal modes specific to methyl terminal – a typical moiety in aliphatic (and phospholipid) membranes. Relative degree of localization and frequencies of the normal modes of methyl terminals make nonlinearities of this moiety to be promising in structural analysis using Sum Frequency Generation imaging. Accordingly, the article describes derivations of relevant macroscopic nonlinearities and suggests a mapping procedure to translate amplitudes of the nonlinearities onto microscopy image plane according to geometry of spherical assembly, local molecular orientation, and optical geometry. Reconstructed images indicate a possibility to extract local curvature of bilayer envelopes of spherical character. This may have practical implications for structural extractions in membrane systems of practical relevance.

  20. Comparison of decomposition characteristics between aromatic and aliphatic VOCs using electron beam

    International Nuclear Information System (INIS)

    The removal efficiency of n-decane (C10H22) by electron beam was the highest among aliphatic VOCs of concern, and that of n-hexane (C6H14), n-butane (C4H10), and methane (CH4) followed. On the other hand, in terms of aromatic VOC decomposition efficiencies, benzene (C6H6) decomposition was the lowest and that of toluene (C7H8), ethylbenzene (C8H10), and p-xylene (C8H10) were similar. It was also found that there was increase in by-product (untreated VOC, CO, CO2, O3, and other compounds) formation as well as all VOC removal efficiencies. It was demonstrated that the removal efficiency of VOC increased as its concentration decreased and the irradiation dose increased. In addition, low removal efficiency was observed because helium was relatively stable compared to the other gases, and nothing but electrons produced by electron accelerator reacted with VOC. It was also found that relative humidity had some effects on the decomposition rates of VOC. The removal efficiency at the 100% RH condition was slightly higher than that at 7.4% RH (dry condition) due to OH radical formation. (author)

  1. A Novel Guided Bone Regeneration Membrane Composed of Nano-hydroxyapatite and Aliphatic Polyester-amide

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Hydrothermally synthesized nano-hydroxyapatite ( n-HA ) varing in weight from 10% to 30%was used as filler to make guided bone regeneration (GBR) composite membranes with novel aliphatic polyesteramide (PEA). The structure and properties of PEA and its n- HA composites were investigated through TEM, IR,XRD , SEM and EDX. The shape and size of the n-HA crystals are similar to the apatite crystals in natural bone.Molecule interactions are present between the n- HA and PEA in the composite, which allows the uniform dispersion of n- HA in PEA matrix. This contributes enhanced mechanical property and bioactivity to the composite. The cytocompatibility of the composites has been investigated by culturing osteoblasts on the membranes. Good cell attachment and proliferation manner were observed on the membranes after 1 week. These results suggest that the PEA/n- HA composite membrane prepared in this study may serve as barrier membranes for guided bone regeneration and potential candidate scaffold for tissue engineering.

  2. Secondary organic aerosol formation from primary aliphatic amines with NO3 radical

    Directory of Open Access Journals (Sweden)

    P. J. Silva

    2009-03-01

    Full Text Available Primary aliphatic amines are an important class of nitrogen containing compounds emitted from automobiles, waste treatment facilities and agricultural animal operations. A series of experiments conducted at the UC-Riverside/CE-CERT Environmental Chamber is presented in which oxidation of methylamine, ethylamine, propylamine, and butylamine with O3 and NO3 have been investigated. Very little aerosol formation is observed in the presence of O3 only. However, after addition of NO, and by extension NO3, large aerosol mass yields (~44% for butylamine are seen. Aerosol generated was determined to be organic in nature due to the small fraction of NO and NO2 in the total signal (<1% for all amines tested as detected by an aerosol mass spectrometer (AMS. We propose a reaction mechanism between carbonyl containing species and the parent amine leading to formation of particulate imine products. These findings can have significant impacts on rural communities with elevated nighttime PM loadings, when significant levels of NO3 exist.

  3. Solid, double-metal cyanide catalysts for synthesis of hyperbranched polyesters and aliphatic polycarbonates

    Indian Academy of Sciences (India)

    Joby Sebastian; Srinivas Darbha

    2014-03-01

    Fe-Zn and Co-Zn double-metal cyanide (DMC) complexes exhibit highly efficient and selective catalytic activity for synthesis of hyperbranched polyesters (glycerol-succinic acid (G-SA) and glycerol-adipic acid (G-AA)) and aliphatic polycarbonates (via., alternative co-polymerization of cyclohexene oxide and CO2), respectively. The influence of method of preparation of DMC, in particular the mode of addition of reagents, on its physicochemical and catalytic properties was investigated. Co-Zn DMC was found highly selective for polycarbonate (than polyethers) formation. Catalysts prepared using tert-butanol and PEG-4000 as complexing and co-complexing agents, respectively, were found superior to those prepared without these agents. Apart from its role as a coordinating ligand, tert-butanol activated the Lewis acidic Zn2+ sites for reactions in polyester and polycarbonate formation. Hydrophobicity, micro-mesoporosity, acid strength and the amount of coordinated complexing agent are some of the crucial factors influenced the catalytic activity of DMC complexes.

  4. [Biodegradation Coefficients of Typical Pollutants in the Plain Rivers Network].

    Science.gov (United States)

    Feng, Shuai; Li, Xu-yongl; Deng, Jian-cai

    2016-05-15

    Biodegradation is a significant part of pollutant integrated degradation, the process rate of which is represented by the biodegradation coefficient. To investigate the biodegradation law of typical pollutants in the plain rivers network located in the upstream of the Lake Taihu, experiments were conducted in site in September 2015, one order kinetics model was used to measure the biodegradation coefficients for permanganate index, ammonia, total nitrogen and total phosphorus, and influencing factors of the biodegradation coefficients were also analyzed. The results showed that the biodegradation coefficients for permanganate index, ammonia, total nitrogen and total phosphorus were 0.008 3-0.126 4 d⁻¹, 0.002 1-0.213 8 d⁻¹, 0.002 1-0.090 5 d⁻¹ and 0.011 0- 0.152 8 d⁻¹, respectively. The influencing factors of the biodegradation coefficients for permanganate index were permanganate index and pH; those for ammonia were ammonia concentration and pH; those for total nitrogen were inorganic nitrogen concentration, total dissolved solid concentration and nitrite concentration; and those for total phosphorus were background concentration and pH. The research results were of important guiding significance for pollutants removal and ecological restoration of the plain rivers network located in the unstream of the Lake Taihu. PMID:27506025

  5. Degradation of oxo-biodegradable plastic by Pleurotus ostreatus.

    Science.gov (United States)

    da Luz, José Maria Rodrigues; Paes, Sirlaine Albino; Nunes, Mateus Dias; da Silva, Marliane de Cássia Soares; Kasuya, Maria Catarina Megumi

    2013-01-01

    Growing concerns regarding the impact of the accumulation of plastic waste over several decades on the environmental have led to the development of biodegradable plastic. These plastics can be degraded by microorganisms and absorbed by the environment and are therefore gaining public support as a possible alternative to petroleum-derived plastics. Among the developed biodegradable plastics, oxo-biodegradable polymers have been used to produce plastic bags. Exposure of this waste plastic to ultraviolet light (UV) or heat can lead to breakage of the polymer chains in the plastic, and the resulting compounds are easily degraded by microorganisms. However, few studies have characterized the microbial degradation of oxo-biodegradable plastics. In this study, we tested the capability of Pleurotus ostreatus to degrade oxo-biodegradable (D2W) plastic without prior physical treatment, such as exposure to UV or thermal heating. After 45 d of incubation in substrate-containing plastic bags, the oxo-biodegradable plastic, which is commonly used in supermarkets, developed cracks and small holes in the plastic surface as a result of the formation of hydroxyl groups and carbon-oxygen bonds. These alterations may be due to laccase activity. Furthermore, we observed the degradation of the dye found in these bags as well as mushroom formation. Thus, P. ostreatus degrades oxo-biodegradable plastics and produces mushrooms using this plastic as substrate. PMID:23967057

  6. Degradation of oxo-biodegradable plastic by Pleurotus ostreatus.

    Directory of Open Access Journals (Sweden)

    José Maria Rodrigues da Luz

    Full Text Available Growing concerns regarding the impact of the accumulation of plastic waste over several decades on the environmental have led to the development of biodegradable plastic. These plastics can be degraded by microorganisms and absorbed by the environment and are therefore gaining public support as a possible alternative to petroleum-derived plastics. Among the developed biodegradable plastics, oxo-biodegradable polymers have been used to produce plastic bags. Exposure of this waste plastic to ultraviolet light (UV or heat can lead to breakage of the polymer chains in the plastic, and the resulting compounds are easily degraded by microorganisms. However, few studies have characterized the microbial degradation of oxo-biodegradable plastics. In this study, we tested the capability of Pleurotus ostreatus to degrade oxo-biodegradable (D2W plastic without prior physical treatment, such as exposure to UV or thermal heating. After 45 d of incubation in substrate-containing plastic bags, the oxo-biodegradable plastic, which is commonly used in supermarkets, developed cracks and small holes in the plastic surface as a result of the formation of hydroxyl groups and carbon-oxygen bonds. These alterations may be due to laccase activity. Furthermore, we observed the degradation of the dye found in these bags as well as mushroom formation. Thus, P. ostreatus degrades oxo-biodegradable plastics and produces mushrooms using this plastic as substrate.

  7. {Polycyclic aromatic hydrocarbons (PAHs) and aliphatic hydrocarbons in gas and particle phases in two sites of Mexico: MILAGRO project}

    Science.gov (United States)

    Amador-Muñoz, O.; Villalobos-Pietrini, R.; Castro, T.; Gaspariano-Larino, R.

    2009-04-01

    Aliphatic hydrocarbons are markers of anthropogenic and biogenic emission sources1; meanwhile PAHs are generated by incomplete combustion sources2. The last ones are important compounds due to their carcinogenic and mutagenic properties3,4. The aim of this study was to identify and quantify aliphatic hydrocarbons and PAHs in gas and particles phases of the atmospheric aerosol and to determine the day and night time behavior during the MILAGRO (Megacity Initiative: Local Global and Research Observations) campaign. The gas phase was collected on polyurethane foam, while particles less than 2.5 m (PM2.5) were collected on glass fiber filters covered with Teflon (TIGF, pallflex) of 8x10 in. Samplings were carried out with a high volume sampler (Tisch) with a flow of 1.13 m3 min-1 at two sites: Instituto Mexicano del Petróleo (T0) and Tecamac (T1) located at North and Northeast of Mexico City, respectively during day (7:00 am-7:00 pm) and night time (7:00 pm-7:00 am) from 1 to 29 of March, 2006. Ninteen PAHs and 23 aliphatic hydrocarbons from n-C13H28 to n-C35H72 were analyzed by gas chromatography coupled to mass spectrometry in impact mode. The samples were spiked with deuterads PAHs and aliphatics hydrocarbons before ultrasound extraction. Medians comparisons were made with Mann-Whitney U test. PAHs with molecular weight (MW) less than 228 g mol-1 were distributed in the gas phase, in both sites. Higher concentrations of PAHs ≥ 228 g mol-1 in PM2.5, were observed during night period (p

  8. Composition and sources of aliphatic lipids and sterols in sediments of a tropical island, southern South China Sea: preliminary assessment.

    Science.gov (United States)

    Mohd Tahir, N; Pang, S Y; Abdullah, N A; Suratman, S

    2013-12-01

    Near-shore surface sediment was collected from five stations off Redang Island located on the eastern coast of Peninsular Malaysia. Freeze-dried sediments were Soxhlet extracted and then fractionated using column chromatography into aliphatic and polar fractions. Determination of these fractions was carried out using gas chromatography mass spectrometry. The concentration of total resolved aliphatic hydrocarbons in sediments ranged from 157 to 308 ng/g. The distribution of aliphatic fraction showed the presence of n-alkanes ranging from nC15 to nC33 with a minor odd-to-even predominance exhibiting carbon maximum, depending on station, at nC17, nC26, nC29 or nC31. Calculation of Carbon Preference Index (CPI) for CPI(15-33) gave values ranging from 1.09 to 1.46. n-Alkanol in all sediment exhibits even-to-odd carbon predominance ranging from nC16 to nC28 and maximising at nC22. n-Fatty acids distribution ranged from nC14 to nC24 with a dominant maximum at nC16 and exhibiting high values of short chain fatty acids (≤nC20) to long chain fatty acids (>nC20) ratios. Unsaturated fatty acids, particularly nC16:1 and nC18:1 is also ubiquitous in all samples. Cholesterol is the most abundant compound amongst the sterol group ranging from 42.8 to 62.6% of the total sterols. β-Sitosterol, brassicasterol and stigmasterol, are also present but of relatively lower amount. These observations suggest that the aliphatic lipids and sterols in the study area originate, mainly, from biogenic sources of marine microbial with minor contribution from epiticular waxes of terrestrial plants.

  9. Synthesis and properties of novel aliphatic polycarbonate from carbon dioxide with 1,2-butylene oxide and ε-caprolactone

    Institute of Scientific and Technical Information of China (English)

    Yan Fei Liu; Ke Long Huang; Dong Ming Peng; Su Qin Liu; Hong Wu

    2007-01-01

    A new degradable aliphatic poly(butylene-co-ε-caprolactone carbonate) (PBCL) was synthesized through the terpolymerization of carbon dioxide, 1,2-butylene oxide (BO) and ε-caprolactone (CL), a polymer supported bimetallic complex (PBM) was used as a catalyst. The terpolymers prepared were characterized by FT-IR, 1H NMR, 13C NMR, WXRD and DSC. The hydrolysis tests were carried out to appraise the degradability of the copolymers.

  10. Analysis of. gamma. -radiolysis products of aqueous solutions of esters of aliphatic amino acids by the PMR method

    Energy Technology Data Exchange (ETDEWEB)

    Panin, V.I.; Sidorov, P.S.; Usatyi, A.F.

    1987-09-01

    The ..gamma..-radiolysis of aqueous solutions of methyl esters of aliphatic amino acids and peptides was investigated by the method of nuclear (proton) magnetic resonance (PMR). The resonance lines appearing in the PMR spectra of the irradiated systems were identified, and a conclusion was drawn about the molecular structure of the radiolysis products. The kinetics of the accumulation of radiolysis products was studied, and the values of their radiation yields were estimated.

  11. Biodegradation of methyl tert-butyl ether by cometabolism with hexane in biofilters inoculated with Pseudomonas aeruginosa.

    Science.gov (United States)

    Salazar, Margarita; Morales, Marcia; Revah, Sergio

    2012-01-01

    Biodegradation of methyl tert-butyl ether (MTBE) vapors by cometabolism with gaseous hexane (n-hexane > 95%) was investigated using Pseudomonas aeruginosa utilizing short chain aliphatic hydrocarbon (C(5)-C(8)). Kinetic batch experiments showed that MTBE was degraded even when hexane was completely exhausted with a cometabolic coefficient of 1.06 ± 0.16 mg MTBE mg hexane(-1). Intermediate tert-butyl alcohol (TBA) accumulation was observed followed by its gradual consumption. A maximum MTBE elimination capacity (EC(MAX)) of 35 g m(-3) h(-1) and removal efficiency (RE) of 70% were attained in mineral medium amended biofilters having an empty bed residence time (EBRT) of 1 min. For these experimental conditions, a maximum hexane EC of approximately 60 g m(-3) h(-1) was obtained at a load of 75 g m(-3) h(-1). Experiments under transient conditions revealed a competitive substrate interaction between MTBE and hexane. Biomass densities between 5.8 and 12.6 g L(biofilter) (-1) were obtained. Nevertheless, production of biopolymers caused non-uniform distribution flow rates that reduced the performance. Residence time distribution profiles showed an intermediate dispersion flow rate with a dispersion coefficient of 0.8 cm(2) s(-1).

  12. Biodegradation of fluoranthene by a newly isolated strain of Bacillus stratosphericus from Mediterranean seawater of the Sfax fishing harbour, Tunisia.

    Science.gov (United States)

    Hentati, Dorra; Chebbi, Alif; Loukil, Slim; Kchaou, Sonia; Godon, Jean-Jacques; Sayadi, Sami; Chamkha, Mohamed

    2016-08-01

    A physico-chemical characterization of seawater taken from the fishing harbour of Sfax, Tunisia, revealed a contamination by organic and inorganic micropollutants. An aerobic marine halotolerant Bacillus stratosphericus strain FLU5 was isolated after enrichment on fluoranthene, a persistent and toxic polycyclic aromatic hydrocarbon (PAH). GC-MS analyses showed that strain FLU5 was capable of degrading almost 45 % of fluoranthene (100 mg l(-1)), without yeast extract added, after 30 days of incubation at 30 g l(-1) NaCl and 37 °C. In addition, the isolate FLU5 showed a remarkable capacity to grow on a wide range of aliphatic, aromatic and complex hydrocarbons. This strain could also synthesize a biosurfactant which was capable of reducing the surface tension of the cell-free medium, during the growth on fluoranthene. The biodegradative abilities of PAHs are promising and can be used to perform the bioremediation strategies of seawaters and marine sediments contaminated by hydrocarbons. PMID:27083911

  13. In-situ micro-FTIR Study of Thermal Changes of Organics in Tagish Lake Meteorite: Behavior of Aliphatic Oxygenated Functions and Effects of Minerals

    Science.gov (United States)

    Kebukawa, Yoko; Nakashima, Satoru; Nakamura-Messenger, Keiko; Zolensky, Michael E.

    2007-01-01

    Systematic in-situ FTIR heating experiments of Tagish Lake meteorite grains have been performed in order to study thermal stability of chondritic organics. Some aliphatic model organic substances have also been used to elucidate effects of hydrous phyllosilicate minerals on the thermal stability of organics. The experimental results indicated that organic matter in the Tagish Lake meteorite might contain oxygenated aliphatic hydrocarbons which are thermally stable carbonyls such as ester and/or C=O in ring compounds. The presence of hydrous phyllosilicate minerals has a pronounced effect on the increase of the thermal stability of aliphatic and oxygenated functions. These oxygenated aliphatic organics in Tagish Lake can be formed during the aqueous alteration in the parent body and the formation temperature condition might be less than 200 C, based especially on the thermal stability of C-O components. The hydrous phyllosilicates might provide sites for organic globule formation and protected some organic decomposition

  14. Distribution and sources of aliphatic hydrocarbons and fatty acids in surface sediments of a tropical estuary south west coast of India (Cochin estuary)

    Digital Repository Service at National Institute of Oceanography (India)

    Gireeshkumar, T.R.; Deepulal, P.M.; Chandramohanakumar, N.

    Surface sediments samples from the Cochin estuary were measured for elemental, stable isotopic and molecular biomarkers (aliphatic hydrocarbons and fatty acids) to study the sources and distribution of sedimentary organic matter. Concentrations...

  15. Aliphatic acid-conjugated antimicrobial peptides--potential agents with anti-tumor, multidrug resistance-reversing activity and enhanced stability.

    Science.gov (United States)

    Deng, Xin; Qiu, Qianqian; Ma, Ke; Wang, Xuekun; Huang, Wenlong; Qian, Hai

    2015-07-28

    Compared with traditional therapeutics, antimicrobial peptides as novel anti-tumor agents have prominent advantages of higher specificity and circumvention of multi-drug resistance. In a previous study, we found that B1, an antimicrobial peptide derived from Cathelicidin-BF15, presented specific anti-tumor activity against several tumor cells. Since aliphatic chain-conjugated peptides have shown ameliorative activity and stability, we conjugated aliphatic acids with different lengths to the amino terminal of B1. All the conjugated peptides exhibited improved anti-tumor activity over B1. Further investigations revealed that the peptides were capable of disrupting the cell membrane, stimulating cytochrome c release into the cytosol, which results in apoptosis. The peptides also acted against multidrug resistant cells and had multidrug resistance-reversing effects. Additionally, conjugation of aliphatic acid enhanced the peptide stability in plasma. In summary, aliphatic acid-modified peptides might be promising anti-tumor agents in the future. PMID:26083110

  16. Segregation and Alteration of Phenolic and Aliphatic Components of Root and Leaf Litter by Detritivores and Microbes

    Science.gov (United States)

    Filley, T. R.; Altmann, J.; Szlavecz, K. A.; Kalbitz, K.; Gamblin, D.; Nierop, K.

    2012-12-01

    The physical and microbial transformation of plant detritus in the litter layer and soil is accompanied by chemical separation of progressively soluble fractions and their movement into the rhizosphere driving subsequent soil processes. We investigated the combined action of specific detritivores, microbial decay, and leaching on the chemical separation of plant aromatic and aliphatic components from root, wood, and leaf tissue using 13C-TMAH thermochemolysis. This method enabled the simultaneous analysis of hydrolyzable tannin and lignin fragments, substituted fatty acids, and condensed tannin composition and revealed process-specific chemical transformations to plant secondary compounds. Long-term incubation and field sampling demonstrated how plant residues are progressively leached of the water soluble, oxidized fragments generated through decay. The residues appeared only slightly altered, in the case of brown rot wood, or enriched in aliphatic fragments, in the case of leaf and root tissue. Water extractable fractions were always selectively dominated by polyphenolics, either as demethylated lignin or tannins, and nearly devoid of aliphatic materials, despite high concentrations in the starting materials. Additionally, for plant materials with high tannin contents, such as pine needles, consumption and passage through some arthropod guts revealed what appeared to be microbially-mediated methylation of phenols, and a loss of tannins in leachates. These findings are indications for an in-situ phenol detoxification mechanism. This research provides important information regarding the links between biochemical decay and the chemical nature of organic matter removed and remaining in the soil profile.

  17. Purified terephthalic acid wastewater biodegradation and toxicity

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xu-xiang; LUO Xiang; GU Ji-dong; WAN Yu-qiu; CHENG Shu-pei; SUN Shi-lei; ZHU Cheng-jun; LI Wei-xin; ZHANG Xiao-chun; WANG Gui-lin; LU Jian-hua

    2005-01-01

    The biodegradation and toxicity of the purified terephthalic acid(PTA) processing wastewater was researched at NJYZ pilot with the fusant strain Fhhh in the carrier activated sludge process(CASP). Sludge loading rate(SLR) for Fhhh to COD of the wastewater was 1.09 d-1 and to PTA in the wastewater was 0.29 d-1. The results of bioassay at the pilot and calculation with software Ebis3 showed that the 48h-LC50 (median lethal concentration) to Daphnia magna for the PTA concentration in the wastewater was only 1/10 of that for the chemical PTA. There were 5 kinds of benzoate pollutants and their toxicities existing in the wastewater at least. The toxicity parameter value of the pure chemical PTA cannot be used to predicate the PTA wastewater toxicity. The toxicity of the NJYZ PTA wastewater will be discussed in detail in this paper.

  18. Biodegradation of Petroleum Hydrocarbons in Soil

    Directory of Open Access Journals (Sweden)

    MR Mehrasbi

    2003-09-01

    Full Text Available Biodegradation of petroleum hydrocarbons (20 g/kg dw soil was investigated in 3 media, differing in the kind of petroleum fractions. In the laboratory experiments, during 5 months, the activities of petroleum hydrocarbon-degrading microorganisms and dehydrogenase activity of soil was determined. Gas chromatographic analysis showed the biological decontaminations for gas oil, kerosene and synthetic mixture (gas oil, kerosene and furnace oil are 60 %, 36 % and 55 %, respectively. Dehydrogenase activity which was assessed by TTC technique, correlated significantly positive with the numbers of microorganisms. The Spearman rank correlation coefficients(r in contaminated soils with gas oil, kerosene and synthetic mixture were 0.79, 0.80 and 0.69, respectively.

  19. Gas foamed open porous biodegradable polymeric microspheres.

    Science.gov (United States)

    Kim, Taek Kyoung; Yoon, Jun Jin; Lee, Doo Sung; Park, Tae Gwan

    2006-01-01

    Highly open porous biodegradable polymeric microspheres were fabricated for use as injectable scaffold microcarriers for cell delivery. A modified water-in-oil-in-water (W1/O/W2) double emulsion solvent evaporation method was employed for producing the microspheres. The incorporation of an effervescent salt, ammonium bicarbonate, in the primary W1 droplets spontaneously produced carbon dioxide and ammonia gas bubbles during the solvent evaporation process, which not only stabilized the primary emulsion, but also created well inter-connected pores in the resultant microspheres. The porous microspheres fabricated under various gas foaming conditions were characterized. The surface pores became as large as 20 microm in diameter with increasing the concentration of ammonium bicarbonate, being sufficient enough for cell infiltration and seeding. These porous scaffold microspheres could be potentially utilized for cultivating cells in a suspension manner and for delivering the seeded cells to the tissue defect site in an injectable manner. PMID:16023197

  20. Biodegradation of the nitramine explosive CL-20.

    Science.gov (United States)

    Trott, Sandra; Nishino, Shirley F; Hawari, Jalal; Spain, Jim C

    2003-03-01

    The cyclic nitramine explosive CL-20 (2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane) was examined in soil microcosms to determine whether it is biodegradable. CL-20 was incubated with a variety of soils. The explosive disappeared in all microcosms except the controls in which microbial activity had been inhibited. CL-20 was degraded most rapidly in garden soil. After 2 days of incubation, about 80% of the initial CL-20 had disappeared. A CL-20-degrading bacterial strain, Agrobacterium sp. strain JS71, was isolated from enrichment cultures containing garden soil as an inoculum, succinate as a carbon source, and CL-20 as a nitrogen source. Growth experiments revealed that strain JS71 used 3 mol of nitrogen per mol of CL-20. PMID:12620886