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  1. AU="Abilio J. F. N. Sobral"
  2. AU="Geller, Alan"
  3. AU=Petrat Sren
  4. AU="Sterling, Shanique"
  5. AU="Qi, Zeqiang"
  6. AU="Thongstisubskul, A"
  7. AU="Daniel C. Schneider, PhD"
  8. AU="Völker, Christoph"
  9. AU="El Aoud, S"
  10. AU="Yi, Tongpei"
  11. AU="Anil K. Mantha"
  12. AU="Artzner, Christoph"
  13. AU=Diana Giovanni
  14. AU="Kinloch, Sabine"
  15. AU="Nuertey, David"
  16. AU="Ojubolamo, Olakunle"

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  1. Article: Bio-based (chitosan/PVA/ZnO) nanocomposites film: Thermally stable and photoluminescence material for removal of organic dye

    Kumar, Santosh / Abilio J.F.N. Sobral / Balu Krishnakumar / Joonseok Koh

    Carbohydrate polymers. 2019 Feb. 01, v. 205

    2019  

    Abstract: Preparation of hitherto unreported chitosan/poly(vinyl alcohol)/ZnO nanocomposites film (designated as CS/PVA/ZnO) as an efficient bio-based nanocomposites is carried out by a greener approach involving mixing, solution casting and solvent evaporation. ... ...

    Abstract Preparation of hitherto unreported chitosan/poly(vinyl alcohol)/ZnO nanocomposites film (designated as CS/PVA/ZnO) as an efficient bio-based nanocomposites is carried out by a greener approach involving mixing, solution casting and solvent evaporation. Synthesized chitosan-based nanocomposites films are characterized by various analytical techniques such as Fourier-transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The photoluminescent properties of CS/PVA/ZnO films are thoroughly studied and compared with CS/PVA. The outcome suggested that the addition of ZnO nanoparticles increased the intensities and red shifting with respect to CS/PVA. The toxicity of chitosan-based nanocomposites films was examined by MTT assay using the NIH3T3 cells. The viability of chitosan-based nanocomposites films was found to be better than native chitosan and PVA films. Furthermore, the adsorption property of prepared chitosan-based nanocomposites films was tested for the removal of AB 1 dye.
    Keywords adsorption ; chitosan ; differential scanning calorimetry ; dyes ; evaporation ; Fourier transform infrared spectroscopy ; mixing ; nanocomposites ; nanoparticles ; photoluminescence ; polyvinyl alcohol ; scanning electron microscopy ; solvents ; thermal stability ; thermogravimetry ; toxicity ; toxicity testing ; transmission electron microscopy ; viability ; X-ray diffraction ; zinc oxide
    Language English
    Dates of publication 2019-0201
    Size p. 559-564.
    Publishing place Elsevier Ltd
    Document type Article
    ZDB-ID 1501516-6
    ISSN 1879-1344 ; 0144-8617
    ISSN (online) 1879-1344
    ISSN 0144-8617
    DOI 10.1016/j.carbpol.2018.10.108
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  2. Article: Flucytosine analogues obtained through Biginelli reaction as efficient combinative antifungal agents

    Wani, Mohmmad Younus / Abilio J.F.N. Sobral / Aijaz Ahmad / Santosh Kumar

    Microbial pathogenesis. 2017 Apr., v. 105

    2017  

    Abstract: Invasive fungal infection is a problem that continues to challenge the healthcare sector. New antifungals and new therapeutic strategies are needed to address this challenge. We previously reported that the combination of a synthetic compound with a drug ...

    Abstract Invasive fungal infection is a problem that continues to challenge the healthcare sector. New antifungals and new therapeutic strategies are needed to address this challenge. We previously reported that the combination of a synthetic compound with a drug with known mechanism of action is a good strategy to treat aggressive and resistant fungi. Here we revisited our approach and synthesized structural analogues of flucytosine, which is a synthetic antifungal and is being studied for its use in combination therapy with other antifungal drugs. Pyrimidin-one and –thione (often known as DHPM's) as flucytosine analogues were obtained through a Biginelli reaction of corresponding aldehydes, ethylacetoacetate and urea/thiourea. Structure was confirmed by FTIR, 1HNMR, 13CNMR, COSY and MS (ESI+) analysis. All the newly synthesized derivatives were evaluated for the antifungal activity alone and in combination of two most commonly used antifungal drugs, amphotericin B and fluconazole against different clinically isolated Candida albicans strains. Minimum inhibitory concentration results confirmed that BG4 possess high antifungal activity against all the tested strains (MIC = 1–32 μg/ml). For all the combinations with amphotericin B and fluconazole, 37% were synergistic followed by 30% additive and 24% indifferent interactions. Interestingly, 9% antagonistic interaction was observed when BG1 and BG3 were combined with fluconazole, however, no antagonistic interaction was observed with amphotericin B. In-depth studies of all the synergies were done by constructing isobolograms with nine different ratio combinations. These results warrant the use of DHPM derivatives as chemosensitising agents which could lower down the dosages of the antifungal drugs to treat invasive fungal diseases.
    Keywords aldehydes ; amphotericin B ; antifungal properties ; Candida albicans ; chemosensitization ; drugs ; fluconazole ; flucytosine ; Fourier transform infrared spectroscopy ; fungi ; health services ; mechanism of action ; minimum inhibitory concentration ; thiourea ; urea
    Language English
    Dates of publication 2017-04
    Size p. 57-62.
    Publishing place Elsevier Ltd
    Document type Article
    ZDB-ID 632772-2
    ISSN 1096-1208 ; 0882-4010
    ISSN (online) 1096-1208
    ISSN 0882-4010
    DOI 10.1016/j.micpath.2017.02.006
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  3. Article ; Online: Characterization of phenolic constituents and evaluation of antioxidant properties of leaves and stems of Eriocephalus africanus

    Marcelo D. Catarino / Artur M.S. Silva / Susana C. Saraiva / Abilio J.F.N. Sobral / Susana M. Cardoso

    Arabian Journal of Chemistry, Vol 11, Iss 1, Pp 62-

    2018  Volume 69

    Abstract: Eriocephalus africanus, an Asteraceae plant endemic from South Africa and naturalized in the Mediterranean region, is commonly used in culinary and in traditional medicine. Despite the claimed health benefits attributed to this plant by the folk medicine, ...

    Abstract Eriocephalus africanus, an Asteraceae plant endemic from South Africa and naturalized in the Mediterranean region, is commonly used in culinary and in traditional medicine. Despite the claimed health benefits attributed to this plant by the folk medicine, there is still a lack of scientific data to support this information. The present study describes the main phenolic composition of hydroethanolic extracts from stems and leaves of E. africanus, along with the assessment of their antioxidant properties. The identification of the phenolic constituents on the stems and leaves from E. africanus was carried out by LC-DAD-ESI/MSn, and the structures of the two major HPLC-eluted compounds were further confirmed by NMR analysis. Both extracts were rich in mono- and di-caffeoylquinic acids, which accounted for approximately 90% and 74% of total quantified phenolics, for the stems and leaves extracts, respectively. Besides, eriodictyol-hexuronide was found in considerable amounts in the extract from the leaves. One must highlight that these compounds together with other minor phenolic acids (namely other caffeoyl, ferulic and protocatechuic acid derivatives) and flavonoids (including hesperetin and eriodictyol) were herein identified for the first time. Furthermore, through three in vitro methods, namely 2,2-diphenyl-1-picrylhydrazyl (DPPH·) radical scavenging, ferric reducing antioxidant power and lipid peroxidation inhibition capacity assays, the antioxidant capacity of the extracts was measured, revealing promising properties. Overall, these results are an important contribution for the elucidation of the phenolic composition of E. africanus, as well as for the understanding of the biological properties of this medicinal plant species.
    Keywords Eriocephalus africanus ; Phenolic compounds ; Caffeoylquinic acid ; Antioxidant ; Mass spectrometry ; Nuclear magnetic resonance ; Chemistry ; QD1-999
    Subject code 540
    Language English
    Publishing date 2018-01-01T00:00:00Z
    Publisher Elsevier
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  4. Article ; Online: Development and validation of a RP-HPLC method for the simultaneous analysis of paracetamol, ibuprofen, olanzapine, and simvastatin during microalgae bioremediation

    Telma Encarnação / António Aguiar / Cátia Palito / Alberto A.C.C. Pais / Maria G. Campos / Abílio J.F.N. Sobral / Hugh D. Burrows

    MethodsX, Vol 7, Iss , Pp 101083- (2020)

    2020  

    Abstract: A rapid reverse phase high-performance liquid chromatography (RP-HPLC) method was developed and validated for the simultaneous quantification of paracetamol, ibuprofen, olanzapine, simvastatin and simvastatin acid in the context of microalgae ... ...

    Abstract A rapid reverse phase high-performance liquid chromatography (RP-HPLC) method was developed and validated for the simultaneous quantification of paracetamol, ibuprofen, olanzapine, simvastatin and simvastatin acid in the context of microalgae bioremediation. The method was validated according to the guidelines of the US Food and Drug Administration (FDA), the International Conference on Harmonization (ICH), and Eurachem with respect to system suitability, linearity, accuracy, precision, recovery, limits of detection and quantification, ruggedness, selectivity and specificity. The estimated limits of detection and quantification were, respectively, 0.03 and 0.10 µg mL−1 for paracetamol, 0.03 and 0.09 µg mL−1 for ibuprofen, 0.04 and 0.13 µg mL−1 for olanzapine, 0.27 and 0.83 µg mL−1 for simvastantin, and 0.05 and 0.14 µg mL−1 for simvastantin acid. The inter-day and intra-day precision results were within the acceptance limit of relative standard deviation (%RSD) of less than 2, and the percentage recovery was found to be within the required limits of 80–110%. The developed method is rapid, linear, precise, robust and accurate, and has been successfully applied to the determination of the above common pharmaceutical products during microalgae bioremediation.
    Keywords Bioremediation ; HPLC ; Method validation ; Microalgae ; Pharmaceuticals ; Wastewater ; Science ; Q
    Subject code 540
    Language English
    Publishing date 2020-01-01T00:00:00Z
    Publisher Elsevier
    Document type Article ; Online
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  5. Article: Effects of biochar addition to estuarine sediments

    Ojeda, Gerardo / Abilio J. F. N. Sobral / Joana Patrício / Stefania Mattana

    Journal of soils and sediments. 2016 Oct., v. 16, no. 10

    2016  

    Abstract: PURPOSE: Biochar is a carbon-rich product, able to enhance soil fertility and mitigate CO₂ emissions. While biochar effects on agriculture are becoming known, its impact elsewhere, e.g., on estuarine ecosystems, has yet to be assessed. The main aim of ... ...

    Abstract PURPOSE: Biochar is a carbon-rich product, able to enhance soil fertility and mitigate CO₂ emissions. While biochar effects on agriculture are becoming known, its impact elsewhere, e.g., on estuarine ecosystems, has yet to be assessed. The main aim of the present study was to determine the effect of biochar on sediment–water retention, CO₂ emissions from sedimentary organic carbon decomposition, sediment pH and electrical conductivity, in aerobic conditions similar to those observed at low tide. MATERIALS AND METHODS: Sediments from the Mondego Estuary (Portugal) were mixed with pine gasification biochar at different doses (5, 10, 14 %) and immersed in water with different salinity values (15, 25, 30) for 96 h. The influence of biochar on water retention, the residence time of water and CO₂ emissions between −0.75 and −1.5 MPa, total organic carbon, pH and electrical conductivity (EC) were determined. Carbon chemical composition and polycyclic aromatic hydrocarbon (PAH) concentrations were determined in sediments and biochar. Differences between biochar treatments after immersion in different water salinities were analysed using the Kruskal–Wallis test. RESULTS AND DISCUSSION: Results showed that biochar was able to (a) increase sediment–water content in terms of quantity and residence time, (b) decrease CO₂ emissions, but only with a specific soil–water content and at the highest biochar dose, (c) increase sediment pH at all biochar doses and (d) increase sediment EC at the highest biochar dose. In contrast, the percentage of carbon mineralised was not modified. Biochar carbon was rich in PAHs and less decomposable than sedimentary carbon. The increments observed in sediment pH and EC were unable to change sediment alkaline or saline status according to standard classifications. CONCLUSIONS: Our results suggest that the remarkable water adsorption capacity of biochar–sediment mixtures may be considered the main factor in regulating CO₂ emission rates from sediments, together with high PAH concentrations, which probably restrain the organic matter decomposition process.
    Keywords adsorption ; aerobic conditions ; biochar ; carbon ; carbon dioxide ; ecosystems ; electrical conductivity ; estuaries ; estuarine sediments ; gasification ; greenhouse gas emissions ; organic matter ; pH ; polycyclic aromatic hydrocarbons ; salinity ; soil fertility ; soil water content ; Portugal
    Language English
    Dates of publication 2016-10
    Size p. 2482-2491.
    Publishing place Springer Berlin Heidelberg
    Document type Article
    ZDB-ID 2050898-0
    ISSN 1614-7480 ; 1439-0108
    ISSN (online) 1614-7480
    ISSN 1439-0108
    DOI 10.1007/s11368-016-1493-3
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    In stock of ZB MED Bonn / Germany

    Z 7702: Show issues

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  6. Article: Carbon dioxide capture and conversion by an environmentally friendly chitosan based meso-tetrakis(4-sulfonatophenyl) porphyrin

    Kumar, Santosh / Abilio J.F.N. Sobral / Joana de A. e Silva / João M. Gil / Mohmmad Y. Wani

    Carbohydrate polymers. 2017 Nov. 01, v. 175

    2017  

    Abstract: We have demonstrated the facile, environmentally friendly and sustainable preparation of chitosan based meso-tetrakis(4-sulfonatophenyl)porphyrin (CS-TPPS) for adsorption and catalytic conversion of carbon-dioxide (CO2). The ionic complexation between ... ...

    Abstract We have demonstrated the facile, environmentally friendly and sustainable preparation of chitosan based meso-tetrakis(4-sulfonatophenyl)porphyrin (CS-TPPS) for adsorption and catalytic conversion of carbon-dioxide (CO2). The ionic complexation between chitosan (CS) and meso-tetrakis(4-sulfonatophenyl)porphyrin (TPPS) is confirmed by ultraviolet-visible (UV–vis) and Fourier transform infrared spectroscopy (FTIR). Physical properties, such as crystallinity, thermal stability, surface morphology and porosity were analyzed by X-ray diffraction, thermal analysis, scanning electron microscopy and BET isotherm analysis. CS-TPPS shows adsorption capacity of 0.9mmol CO2/g compared to the adsorption capacity of 0.05mmol CO2/g of pure chitosan and an adsorption capacity of 0.2mmol CO2/g of pure TPPS. It also exhibits higher conversion of CO2 and propylene oxide into cyclic carbonate (66%), compared to pure chitosan (31%). The results are encouraging, and may open new perspectives for the use of biopolymers involving porphyrin based material in environmental and industrial applications.
    Keywords adsorption ; biopolymers ; carbon dioxide ; chitosan ; crystal structure ; Fourier transform infrared spectroscopy ; industrial applications ; porosity ; porphyrins ; propylene oxide ; scanning electron microscopy ; thermal analysis ; thermal stability ; ultraviolet-visible spectroscopy ; X-ray diffraction
    Language English
    Dates of publication 2017-1101
    Size p. 575-583.
    Publishing place Elsevier Ltd
    Document type Article
    ZDB-ID 1501516-6
    ISSN 1879-1344 ; 0144-8617
    ISSN (online) 1879-1344
    ISSN 0144-8617
    DOI 10.1016/j.carbpol.2017.08.031
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  7. Article: Monitoring oil production for biobased feedstock in the microalga Nannochloropsis sp.: a novel method combining the BODIPY BD-C12 fluorescent probe and simple image processing

    Encarnação, Telma / Abílio J. F. N. Sobral / Alberto A. C. C. Pais / Cláudia T. Arranja / Hugh D. Burrows / Maria G. Campos / Tânia F. G. G. Cova

    Journal of applied phycology. 2018 Aug., v. 30, no. 4

    2018  

    Abstract: A simple reliable method with fast response for lipid detection and quantification is proposed, combining a new highly lipophilic fluorescent probe BODIPY BD-C12 and image analysis to determine the algal lipid content and the lipid production in the ... ...

    Abstract A simple reliable method with fast response for lipid detection and quantification is proposed, combining a new highly lipophilic fluorescent probe BODIPY BD-C12 and image analysis to determine the algal lipid content and the lipid production in the microalgae Nannochloropsis sp. Lipid bodies stained with BODIPY BD-C12 have a characteristic multicolor fluorescence, and their volumes were determined using a sphere volume approach. The method developed was applied in the evaluation of lipid accumulation by Nannochloropsis sp. under different cultivation conditions (varying nitrate and salinity concentrations and combined effect of these two variables). The results show an increase of lipid content in Nannochloropsis sp. cultivated in nitrogen replete and depleted conditions, from 9.4 to 40.8 μm3 cell−1 and 35.5 to 73.5%, respectively. The findings are also compared with conventional methods for determination of neutral lipids and with results obtained from the dyes Nile Red and BODIPY 505/515. A reasonable agreement between neutral lipid production measured by BODIPY BD-C12 and gravimetric methods (correlation coefficient of 0.98) was obtained. The neutral lipids production decreased from 964.6 to 244.8 mg L−1 and from 809.1 to 396.7 mg L−1, as the nitrate concentration increased from 0 to 0.3 g L−1. It is observed that, with the two commercially available dyes, lipid quantification using Nile Red leads to an overestimation of lipids, while the use of BODIPY 505/515 promoted unreliable measures due to rapid bleaching of the chromophore. The method proposed shows excellent potential to become a standard, yet advanced, strategy for rapid evaluation and quantification of intracellular lipids in microalgae, a crucial step of the scaling-up process involved in the production of biobased products.
    Keywords biobased products ; bleaching ; feedstocks ; fluorescence ; fluorescent dyes ; gravimetry ; image analysis ; lipid bodies ; lipid content ; lipophilicity ; microalgae ; monitoring ; Nannochloropsis ; nitrates ; nitrogen ; oils ; salinity ; triacylglycerols
    Language English
    Dates of publication 2018-08
    Size p. 2273-2285.
    Publishing place Springer Netherlands
    Document type Article
    ZDB-ID 1002324-0
    ISSN 1573-5176 ; 0921-8971
    ISSN (online) 1573-5176
    ISSN 0921-8971
    DOI 10.1007/s10811-018-1437-y
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    In stock of ZB MED Bonn / Germany

    Z 89/703: Show issues

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  8. Article ; Online: Poly[μ2-aqua-μ4-[1-(4-chlorophenyl)-4,4,4-trifluorobutane-1,3-dionato]-potassium]

    João P. Martins / Cláudia C. Arranja / Abílio J. F. N. Sobral / Manuela Ramos Silva

    Acta Crystallographica Section E, Vol 69, Iss 7, Pp m422-m

    2013  Volume 423

    Abstract: In the title compound, [K(C10H5ClO2F3)(H2O)]n, the two independent K+ ions are located on a twofold rotation axis. For each of the cations, the distorted cubic coordination environment is defined by two F and four O atoms of symmetry-related 1,4- ... ...

    Abstract In the title compound, [K(C10H5ClO2F3)(H2O)]n, the two independent K+ ions are located on a twofold rotation axis. For each of the cations, the distorted cubic coordination environment is defined by two F and four O atoms of symmetry-related 1,4-chlorophenyl-4,4,4-trifluorobutane-1,3-dionate anions and by two O atoms of water molecules. The μ4-bridging character of the anion and the μ2-bridging of the water molecule lead to the formation of layers parallel to (100). The coordinating water molecules are also involved in O—H.O hydrogen bonds that reinforce the molecular cohesion within the layers, which are stacked along [100]. The β-diketonate anion is not planar, with an angle of 31.78 (10)° between the mean planes of the diketonate group and the chlorophenyl ring.
    Keywords Chemistry ; QD1-999
    Language English
    Publishing date 2013-07-01T00:00:00Z
    Publisher International Union of Crystallography
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  9. Article ; Online: 4,7-Diphenyl-1,10-phenanthroline methanol hemisolvate

    João P. Martins / Pablo Martín-Ramos / Abílio J. F. N. Sobral / Manuela Ramos Silva

    Acta Crystallographica Section E, Vol 69, Iss 7, Pp o1018-o

    2013  Volume 1018

    Abstract: The asymmetric unit of the title compound, C24H16N2·0.5CH3OH, is comprised of two independent bathophenanthroline molecules (systematic name: 4,7-diphenyl-1,10-phenanthroline) and one methanol molecule. The bathophenanthroline molecules are not planar as ...

    Abstract The asymmetric unit of the title compound, C24H16N2·0.5CH3OH, is comprised of two independent bathophenanthroline molecules (systematic name: 4,7-diphenyl-1,10-phenanthroline) and one methanol molecule. The bathophenanthroline molecules are not planar as there is a considerable rotation of all terminal phenyl rings with respect to the central phenanthroline units [dihedral angles in the range 52.21 (12)–62.14 (10)°]. In addition, a non-negligible torsion is apparent in one of the phenanthroline units: the angle between the mean planes of the two pyridine rings is 14.84 (13)°. The methanol solvent molecule is linked to both N atoms of a bathophenanthroline molecule through a bifurcated O—H.(N,N) hydrogen bond.
    Keywords Chemistry ; QD1-999
    Language English
    Publishing date 2013-07-01T00:00:00Z
    Publisher International Union of Crystallography
    Document type Article ; Online
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  10. Article ; Online: Photophysical Characterization and in Vitro Phototoxicity Evaluation of 5,10,15,20-Tetra(quinolin-2-yl)porphyrin as a Potential Sensitizer for Photodynamic Therapy

    Letícia D. Costa / Joana de A. e Silva / Sofia M. Fonseca / Cláudia T. Arranja / Ana M. Urbano / Abilio J.F.N. Sobral

    Molecules, Vol 21, Iss 4, p

    2016  Volume 439

    Abstract: Photodynamic therapy (PDT) is a selective and minimally invasive therapeutic approach, involving the combination of a light-sensitive compound, called a photosensitizer (PS), visible light and molecular oxygen. The interaction of these per se harmless ... ...

    Abstract Photodynamic therapy (PDT) is a selective and minimally invasive therapeutic approach, involving the combination of a light-sensitive compound, called a photosensitizer (PS), visible light and molecular oxygen. The interaction of these per se harmless agents results in the production of reactive species. This triggers a series of cellular events that culminate in the selective destruction of cancer cells, inside which the photosensitizer preferentially accumulates. The search for ideal PDT photosensitizers has been a very active field of research, with a special focus on porphyrins and porphyrin-related macrocycle molecules. The present study describes the photophysical characterization and in vitro phototoxicity evaluation of 5,10,15,20-tetra(quinolin-2-yl)porphyrin (2-TQP) as a potential PDT photosensitizer. Molar absorption coefficients were determined from the corresponding absorption spectrum, the fluorescence quantum yield was calculated using 5,10,15,20-tetraphenylporphyrin (TPP) as a standard and the quantum yield of singlet oxygen generation was determined by direct phosphorescence measurements. Toxicity evaluations (in the presence and absence of irradiation) were performed against HT29 colorectal adenocarcinoma cancer cells. The results from this preliminary study show that the hydrophobic 2-TQP fulfills several critical requirements for a good PDT photosensitizer, namely a high quantum yield of singlet oxygen generation (Φ∆ 0.62), absence of dark toxicity and significant in vitro phototoxicity for concentrations in the micromolar range.
    Keywords photodynamic therapy ; photosensitizers ; porphyrins ; cancer ; HT29 cells ; Organic chemistry ; QD241-441
    Subject code 610
    Language English
    Publishing date 2016-03-01T00:00:00Z
    Publisher MDPI AG
    Document type Article ; Online
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