26 research outputs found

    Systematic hydrolysis of PIM-1 and electrospinning of hydrolyzed PIM-1 ultrafine fibers for an efficient removal of dye from water

    Get PDF
    In this study, the Polymer of Intrinsic Microporosity (PIM-1) was systematically hydrolyzed in the presence of sodium hydroxide by varying the concentration of base, washing procedure and the time of the reaction. The chemical structure analyses confirmed that PIM-1 could be hydrolyzed by 65% up to 99% conversion depending on the synthesis procedure. The hydrolyzed PIM-1 samples have shown improved solubility which facilitates the fabrication of hydrolyzed PIM-1 ultrafine fibers by electrospinning technique. Extensive optimization studies were performed for the electrospinning of uniform and bead-free fibers from hydrolyzed PIM-1 with different degree of hydrolysis (65%, 86%, 94% and 99%). The electrospun hydrolysed PIM-1 fibrous samples have average fiber diameters (AFD) ranging from 0.58 ± 0.15 μm to 1.21 ± 0.15 μm, depending on the polymer concentration and applied electrospinning parameters. After electrospinning, self-standing hydrolyzed PIM-1 fibrous membranes were obtained which is useful as a filtering material for the adsorption of organic dyes from wastewater. Here, the capability of hydrolyzed PIM-1 electrospun fibrous membranes for the removal of dyes from aqueous solutions was investigated by using a batch adsorption process. The maximum adsorption capacity of fully hydrolyzed PIM-1 fibers was found 157 ± 16 mg g− 1 for Methylene Blue and 4 mg g− 1 for Congo red when the adsorption was conducted by 20 mg L− 1 dye solution without using any dilution. Moreover, maximum dye adsorption was also studied by using concentrated Methylene Blue solutions showing up to 272 mg g− 1 adsorption maximum. In addition, the self-standing fibrous hydrolyzed PIM-1 membrane was employed to separate Methylene Blue from an aqueous system by filtration without the necessity of additional driving force. The results indicate that hydrolyzed PIM-1 electrospun nanofibrous membranes can be a promising filtering material for wastewater treatment © 2017 Elsevier B.V

    Comparison of pure and mixed gas permeation of the highly fluorinated polymer of intrinsic microporosity PIM-2 under dry and humid conditions: Experiment and modelling

    Get PDF
    This manuscript describes the gas separation performance of PIM-2, a partially fluorinated linear copolymer synthesized from 5,5',6,6'-tetrahydroxy-3,3,3',3'-tetramethylspirobisindane (TTSBI) and decafluorobiphenyl (DFBP). As one of the early members of the family of polymers of intrinsic microporosity, it had never been tested as a gas separation membrane because of insufficient mechanical resistance. This has been solved only recently, allowing the preparation of robust self-standing films. Molecular modelling studies demonstrated a high fractional free volume (34%) and an elevated surface area (642 m2 g-1), and the latter is in good agreement with experimental BET results. Pure gas permeabilities measured on a fixed-volume time-lag instrument at 1 bar compare well with the results of mixed separation tests on a variable volume setup from 1-6 bar(a). Molecular modelling and independent sorption measurements on a gravimetric sorption balance both show strong dual-mode sorption behaviour, especially for CO2 and to a lesser extent for CH4. Temperature-dependent pure gas permeation measurements show typical Arrhenius behaviour, with a clear increase in the activation energy for diffusion with the increasing molecular size of the gas, indicating high size-selectivity. This is in agreement with the highly rigid PIM structure, determined by AFM force spectroscopy measurements. The dual-mode behaviour results in a moderate pressure dependence of the CO2 permeability and the CO2/N2 and CO2/CH4 selectivity, all slightly decreasing with increasing pressure. The presence of humidity in the gas stream has a remarkable small effect on the membrane performance, which is probably due to the high fluorine content and the consequently low water vapour solubility in the polymer, as confirmed by gravimetric sorption measurements. The manuscript describes an extensive study on the structure-property relationships in PIM-2. © 2019 Elsevier B.V.European Commission, EC Grantová Agentura Ceské Republiky, GA Ä?R: 18-05484S --Research on biogas upgrading presented in this work was supported by EU structural funding in the frame of Operational Programme Research, Development and Education, project No. CZ.02.1.01./0.0/0.0/17_049/0008419 “COOPERATION”. This work was further supported by the CNR-CAS bilateral agreement 2016–2018 “Innovative polymeric membranes for pervaporation and advanced gas and vapour separations” and by the Czech Science Foundation (grant no. 18-05484S ). Appendix A -

    Spawning of bluefin tuna in the black sea: historical evidence, environmental constraints and population plasticity

    Get PDF
    <div><p>The lucrative and highly migratory Atlantic bluefin tuna, <em>Thunnus thynnus</em> (Linnaeus 1758<em>;</em> Scombridae), used to be distributed widely throughout the north Atlantic Ocean, Mediterranean Sea and Black Sea. Its migrations have supported sustainable fisheries and impacted local cultures since antiquity, but its biogeographic range has contracted since the 1950s. Most recently, the species disappeared from the Black Sea in the late 1980s and has not yet recovered. Reasons for the Black Sea disappearance, and the species-wide range contraction, are unclear. However bluefin tuna formerly foraged and possibly spawned in the Black Sea. Loss of a locally-reproducing population would represent a decline in population richness, and an increase in species vulnerability to perturbations such as exploitation and environmental change. Here we identify the main genetic and phenotypic adaptations that the population must have (had) in order to reproduce successfully in the specific hydrographic (estuarine) conditions of the Black Sea. By comparing hydrographic conditions in spawning areas of the three species of bluefin tunas, and applying a mechanistic model of egg buoyancy and sinking rate, we show that reproduction in the Black Sea must have required specific adaptations of egg buoyancy, fertilisation and development for reproductive success. Such adaptations by local populations of marine fish species spawning in estuarine areas are common as is evident from a meta-analysis of egg buoyancy data from 16 species of fish. We conclude that these adaptations would have been necessary for successful local reproduction by bluefin tuna in the Black Sea, and that a locally-adapted reproducing population may have disappeared. Recovery of bluefin tuna in the Black Sea, either for spawning or foraging, will occur fastest if any remaining locally adapted individuals are allowed to survive, and by conservation and recovery of depleted Mediterranean populations which could through time re-establish local Black Sea spawning and foraging.</p> </div

    Amidoxime functionalized Polymers of Intrinsic Microporosity (PIM-1) electrospun ultrafine fibers for rapid removal of uranyl ions from water

    No full text
    The Polymers of Intrinsic Microporosity (PIM-1) is considered as one of the most promising polymer candidates for adsorption applications owing to its high surface area and the ability to tailor the functionality for the targeted species. This study reports a facile method for the preparation of amidoxime functionalized PIM-1 fibrous membrane (AF-PIM-FM) by electrospinning technique and its practical use for the extraction of U(VI) ions from aqueous systems via column sorption under continuous flow. Fibrous membrane form of amidoxime functionalized PIM-1 (AF-PIM-FM) was prepared by electrospinning method owing to its excellent processability in dimethylformamide. Bead-free and uniform fibers were obtained as confirmed by SEM imaging and average fiber diameter was 1.69 ± 0.34 μm for AF-PIM-FM. In addition, electrospun PIM-1 fibrous membrane (PIM-FM) was prepared as a control group. Structural and thermal characterization of powder and membrane forms of the materials were performed using FT-IR, 1 H NMR, XPS, Elemental analyses, TGA, and DSC. The porosity of the samples was measured by N2 sorption isotherms confirming amidoxime PIM-1 still maintain their porosity after functionalization. Amidoxime functionality along with membrane structure makes AF-PIM-FM a promising material for uranyl adsorption. First, a comparison between powder and membrane form of amidoxime functionalized PIM-1 was investigated using batch adsorption process. Although membrane form has shown slightly lower adsorption performance in the batch adsorption process, the advantage of using the membrane in column adsorption processes makes membrane form more feasible for real applications. In addition, amidoxime modification enhanced the uranium adsorption ability of PIM-FM up to 20 times. The effect of initial concentration and pH were investigated along with regeneration of the adsorbents. AF-PIM-FM was successfully used for five adsorption-desorption cycles without having any damage on the fibrous structure

    Samples of Kidney Transplant Patients

    No full text
    Solid organ transplantation is an important therapeutic choice to improve the life quality of patients with end-stage renal disease. Renal transplant recipients have to take immunosuppressive therapy to prevent transplant rejection. However, this treatment increases susceptibility to infection. Bartonella henselae causes systemic, disseminated and silent manifestations in healthy individuals, while the mortality rate is high in immunosuppressive patients in the case of untreated bartonellosis. The diagnosis of B.henselae infections is usually based on serological methods since they are practical, simple and rapid. Recent reports indicated that bartonellosis seen after liver or kidney transplantation have been increased. The aim of this study was to present the antibody seropositivity of B.henselae detected in the serum and plasma samples of renal transplant recipients. This study was aimed to evaluate the antibody seroprevalence in renal transplant recipients and also to compare the antibody results obtained from serum and plasma samples. A total of 59 renal transplant recipients (32 male, 27 female; age range: 20-65 years) followed by Transplantation Unit of Health, Research and Training Center of Pamukkale University, were included in the study. After suspension of lyophilised B.henselae ATCC 49882 (Houston-1); B.henselae co-cultivation to Vero cell culture was performed by the method recommended by Zbinden et al. [Clin Diagn Lab Immunol 1995; 2(6): 693-5]. The cells were taken to co-cultivation in flasks after development of monolayers. In house immunofluorescence antibody (IFA) method was performed with the use of infected cell-coated slides. B.henselae antibodies were studied at 1/64 screening dilution both in serum and plasma samples. In our study B.henselae antibody positivity rates found in serum and plasma samples of the patients were 16.9% (10/59) and 6.8% (4/59), respectively (Cohen kappa = 0.37). This detected kappa value indicated that the results of serum and plasma samples revealed "fair agreement". It should be kept in mind that the use of plasma samples in IFA tests would increase the false negative results. Thus the results of this study supported the general approach for the preference of serum samples for serological tests

    Samples of Kidney Transplant Patients

    No full text
    Solid organ transplantation is an important therapeutic choice to improve the life quality of patients with end-stage renal disease. Renal transplant recipients have to take immunosuppressive therapy to prevent transplant rejection. However, this treatment increases susceptibility to infection. Bartonella henselae causes systemic, disseminated and silent manifestations in healthy individuals, while the mortality rate is high in immunosuppressive patients in the case of untreated bartonellosis. The diagnosis of B.henselae infections is usually based on serological methods since they are practical, simple and rapid. Recent reports indicated that bartonellosis seen after liver or kidney transplantation have been increased. The aim of this study was to present the antibody seropositivity of B.henselae detected in the serum and plasma samples of renal transplant recipients. This study was aimed to evaluate the antibody seroprevalence in renal transplant recipients and also to compare the antibody results obtained from serum and plasma samples. A total of 59 renal transplant recipients (32 male, 27 female; age range: 20-65 years) followed by Transplantation Unit of Health, Research and Training Center of Pamukkale University, were included in the study. After suspension of lyophilised B.henselae ATCC 49882 (Houston-1); B.henselae co-cultivation to Vero cell culture was performed by the method recommended by Zbinden et al. [Clin Diagn Lab Immunol 1995; 2(6): 693-5]. The cells were taken to co-cultivation in flasks after development of monolayers. In house immunofluorescence antibody (IFA) method was performed with the use of infected cell-coated slides. B.henselae antibodies were studied at 1/64 screening dilution both in serum and plasma samples. In our study B.henselae antibody positivity rates found in serum and plasma samples of the patients were 16.9% (10/59) and 6.8% (4/59), respectively (Cohen kappa = 0.37). This detected kappa value indicated that the results of serum and plasma samples revealed "fair agreement". It should be kept in mind that the use of plasma samples in IFA tests would increase the false negative results. Thus the results of this study supported the general approach for the preference of serum samples for serological tests

    Screen use habits among children and adolescents with psychiatric disorders: A cross-sectional study from Turkey

    No full text
    In this cross-sectional study, we investigated screen use habits, problematic internet use (PIU), and screen-psychopathology relationship in a clinical sample of children and adolescents. The study included 277 children and adolescents (129 [46.4%] girls) aged between 6-17 years referred to a psychiatry outpatient setting for various reasons. All parents completed the Strengths and Difficulties Questionnaire (SDQ), while adolescents also completed the Internet Addiction Test (IAT). The mean screen time was 3.85 (SD = 2.72) hours per day. Longer screen times were found among children and adolescents with specific psychiatric disorders compared to those with no psychiatric symptoms; especially among those with internalizing disorders (i.e., an anxiety disorder and/or depression), but also with attention deficit/hyperactivity disorder and/or conduct disorder. Longer screen time may be related with more functioning impairments. Based on the IAT, 2.1% of adolescents may have PIU. The findings from this study suggest that children and adolescents with psychiatric symptoms may have prolonged screen times. This needs to be taken into account during diagnostic and therapeutic procedures. © 2020 by authors

    Disorders: A Cross-Sectional Study from Turkey

    No full text
    In this cross-sectional study, we investigated screen use habits, problematic internet use (PIU), and screen-psychopathology relationship in a clinical sample of children and adolescents. The study included 277 children and adolescents (129 [46.4%] girls) aged between 6-17 years referred to a psychiatry outpatient setting for various reasons. All parents completed the Strengths and Difficulties Questionnaire (SDQ), while adolescents also completed the Internet Addiction Test (IAT). The mean screen time was 3.85 (SD = 2.72) hours per day. Longer screen times were found among children and adolescents with specific psychiatric disorders compared to those with no psychiatric symptoms; especially among those with internalizing disorders (i.e., an anxiety disorder and/or depression), but also with attention deficit/hyperactivity disorder and/or conduct disorder. Longer screen time may be related with more functioning impairments. Based on the IAT, 2.1% of adolescents may have PIU. The findings from this study suggest that children and adolescents with psychiatric symptoms may have prolonged screen times. This needs to be taken into account during diagnostic and therapeutic procedures.C1 [Basay, Burge Kabukcu; Basay, Omer; Akdogan, Cemre; Karaisli, Seyma; Satilmis, Merve; Gozen, Burcu; Sekerci, Naci Bahadir; Co, Omerbasaygmail] Pamukkale Univ, Med Fac, Child & Adolescent Psychiat Dept, Denizli, Turkey
    corecore