1,807 research outputs found
Rezension: Feminismus revisited: von Erica Fischer
No full textErica Fischer beschäftigt sich in „Feminismus revisited“ mit der Frage, inwieweit die in den 1970er-Jahren geführten feministischen Kämpfe noch heute Relevanz haben und weiter ausgefochten werden, was sich seit dem verändert hat und wo es Anknüpfungspunkte zwischen heutigen und damaligen feministischen Debatten gibt.In "Feminism revisited", Erica Fischer explores the extent to which the feminist struggles of the 1970s are still important today and continue to be relevant, what has changed since then and where there are links between contemporary and then feminist debates
Vicarious Victimhood as Post-Holocaust Jewish Identity in Erica Fischer\u27s Auto/Biography Aimée and Jaguar
No full textIn her article Vicarious Victimhood as Post-Holocaust Jewish Identity in Erica Fischer\u27s Auto/Biography Aimée and Jaguar Anne Rothe reads the Austrian-Jewish journalist\u27s interview-based dual biography in autobiographical terms. Taking recourse to such para-texts as the preface and epilogue, in which Fischer reflects on her own subject position, in addition to the auto/biographical narrative itself, Rothe critiques the notion of constructing secular Jewish identity based on the notion of vicarious or hereditary Holocaust victimhood. This provocative new reading reveals that the biography Fischer wrote constitutes a counter-narrative to the story her main collaborator, Lilly Wust, told the author about her short-lived love affair with Felice Schragenheim, who was killed in the Holocaust and whom Wust mourned for the rest of her life. Rothe furthermore argues that Fischer rewrites Wust\u27s story to the extent of denying her core identity of vicarious Holocaust victimhood, only to claim this epistemologically and ethically untenable but culturally dominant and coveted subject position for herself
FT Raman investigation of sodium cellulose sulfate
No full textFT Raman investigation of sodium cellulose sulfates (NaCS) was reported. Different NaCS were prepared by two diverse sulfation methods and their total degrees of substitution (DS) of sulfate groups were determined through either 13C-NMR spectroscopy or elemental analysis. Subsequently, these NaCS were characterized with FT Raman spectroscopy. The caused bands through the introduction of the sulfate groups in cellulose chain were explained and assigned. Additionally, a strong linear correlation between the areas under the bands ascribed to the stretching vibrations of C–O–S groups and the total DS of NaCS was presented. A rapid method of quantifying the total DS of NaCS was established. Finally, sodium sulfate (Na2SO4), a salt that is very often produced during the sulfation of cellulose, was found to be analyzable even with a weight content of 0.12% in NaCS. The method of quantifying the content of this salt in NaCS was investigated with Raman spectroscopy
Synthesis and spectroscopic analysis of cellulose sulfates with regulable total degrees of substitution and sulfation patterns via 13C NMR and FT Raman spectroscopy
No full textSynthesis and spectroscopic characterisation of cellulose sulfate (CS) were reported. Various CS exhibiting diverse degrees of sulfation (DSS) were prepared through acetosulfation or direct sulfation of cellulose. During the acetosulfation, intermediate product – cellulose acetate sulfate (CAS) – was formed after the comparative esterification and subsequent deacetylation of CAS led to CS. The direct sulfation proceeded quasi-homogeneously and heterogeneously in N,N-dimethylformamide (DMF) or homogeneously in N,N-dimethylacetamide (DMAc)/LiCl mixture. The total DSS between 0.21–2.59 and partial DSS6 as well as DSS2 of up to 1 were determined via elemental analysis and 13C NMR spectroscopy. Besides, solid-state CP/MAS 13C NMR could characterise CS regarding the sulfation. Subsequently, FT Raman investigation of obtained CS was conducted with the aim to establish analysis methods quantifying the total DSS. The intensities of Raman bands ascribed to the vibrations of OSO and C–O–S groups were used as analysis parameters, yielding calibration curves with high correlation coefficients of more than 0.96
Analysis of carboxylate groups in oxidized never-dried cellulose II catalyzed by TEMPO and 4-acetamide-TEMPO
No full textIn this report, never-dried regenerated celluloses, i.e. cellulose II, from their NaOH/urea/H2O solutions were subjected to TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl) or 4-acetamide-TEMPO-mediated oxidation. Water-soluble and -insoluble fractions of carboxyl cellulose (COC) were obtained and their DO were determined to be between 0.08 and 0.85. Apart from conductometric titration, complexometric titration with EDTA was used to analyze the DO of COC. The conductometric titration can be used for lowly or highly oxidized celluloses, while the complexometric titration with EDTA is only adequate for COC with DO lower than 0.6. FT Raman spectroscopy represents characteristic bands of carboxyl and carboxylate groups. It demonstrates the feasibility of establishing novel analyzing methods for DO of COC with high correlation coefficients of up to 0.9867. Moreover, long oxidation duration, high temperature and high amounts of oxidizing agents are important for the synthesis of COC with high DO and yields
Synthesis and characterization of low sulfoethylated cellulose
No full textThe synthesis and characterization of sulfoethyl cellulose (SEC) exhibiting low degrees of substitution ascribed to sulfoethyl groups (DSSE) were reported. The effects of reaction temperature, duration, reaction mediums as well as sulfoethylating agents on DSSE were investigated. The total DSSE was determined via elemental analysis and the structure of SEC was elucidated by FT Raman, one- (1D-) and two-dimensional (2D-) NMR spectroscopy. Based on the characterization, SEC with diverse total DSSE up to 0.65 were obtained and the primary hydroxyl groups were found to be preferably substituted. Finally, the feasibility of using FT Raman spectroscopy with the band at 1044, 811 or 747 cm−1 as marker band to determine total DSSE of SEC was presented
Fig. 1 in Study of some European wild hybrids of Erica L. (Ericaceae), with descriptions of a new nothospecies: Erica nelsonii Fagúndez and a new nothosubspecies: Erica veitchii nothosubsp. asturica Fagúndez
No full textFig. 1. – Erica ×nelsonii Fagúndez. A. Synflorescence of upper left fragment (typus); B. General view of upper right fragment. [P. F. Hunt 1636, K] [Drawn by the author]Published as part of Fagúndez, Jaime, 2012, Study of some European wild hybrids of Erica L. (Ericaceae), with descriptions of a new nothospecies: Erica nelsonii Fagúndez and a new nothosubspecies: Erica veitchii nothosubsp. asturica Fagúndez, pp. 51-57 in Candollea 67 (1) on page 53, DOI: 10.15553/c2012v671a7, http://zenodo.org/record/576238
Solid-State Spectroscopic Characterization of α-Chitins Deacetylated in Homogeneous Solutions
No full textControlling water transportation within hydrogels makes hydrogels attractive for diverse applications, but it is still a very challenging task. Herein, a novel type of dually electrostatically crosslinked nanocomposite hydrogel showing thermoresponsive water absorption, distribution, and dehydration processes are developed. The nanocomposite hydrogels are stabilized via electrostatic interactions between negatively charged poly(acrylic acid) and positively charged layered double hydroxide (LDH) nanosheets as well as poly(3‐acrylamidopropyltrimethylammonium chloride). Both LDH nanosheets as crosslinkers and the surrounding temperatures played pivotal roles in tuning the water transportation within these nanocomposite hydrogels. By changing the surrounding temperature from 60 to 4 °C, these hydrogels showed widely adjustable swelling times between 2 and 45 days, while the dehydration process lasted between 7 and 27 days. A swift temperature decrease, for example, from 60 to 25 °C, generated supersaturation within these nanocomposite hydrogels, which further retarded the water transportation and distribution in hydrogel networks. Benefiting from modified water transportation and rapidly alternating water uptake capability during temperature change, pre‐loaded compounds can be used to track and visualize these processes within nanocomposite hydrogels. At the same time, the discharge of water and loaded compounds from the interior of hydrogels demonstrates a thermoresponsive sustained release process
Synthesis of carboxyl cellulose sulfates with regioselective sulfation and regiospecific oxidation using cellulose trifluoroacetate as intermediates
No full textSynthesis of cellulose sulfates (CSs) and carboxyl cellulose sulfates (COCSs) with regioselectively or regiospecifically distributed functional groups within anhydroglucose units was reported. CS with regioselectively distributed sulfate groups at 2,3-O- or 2,6-O-position were homogeneously synthesized and cellulose trifluoroacetate (CTFA) was used as intermediates. The trifluoroacetyl groups were detected primarily at 6-O-position and their distributions could be altered by changing the amount of trifluoroacetyl anhydride (TFAA). Various sulfating agents were used for further homogeneous sulfation of CTFA. The total degree of sulfation (DSS) and the distribution of sulfate groups within the repeating units were affected by the amount of TFAA, the type and amount of sulfating agents. Subsequent homogenous 4-acetamide-TEMPO or TEMPO-mediated oxidation of CS led to COCS with carboxyl groups regiospecifically distributed at C6 position, which may be interesting structural mimics for natural occurring heparin
Synthesis and Bioactivity of Cellulose Derivatives
No full textCellulose derivatives having carboxyl‐ or carboxymethyl‐ and sulphate groups were synthesized with control of reaction conditions to regulate the distribution of substituents and molecular weights of the products. Sodium cellulose sulphates (NaCS) were synthesized through acetosulphation of cellulose or direct sulphating of cellulose and cellulose‐2.5‐acetate (C2.5A). The properties of the products were controlled by choice of starting materials and reaction parameters like reaction temperature and duration. Cellulose sulphates containing carboxyl groups were prepared through oxidation with 2,2,6,6‐tetramethylpiperidine‐1‐oxyl radical (TEMPO)/NaBr/NaClO in water or through carboxymethylation with chloroacetic acid after alkali treatment with sodium hydroxide. The biological activity of the products was analyzed with a binding assay to fibroblast growth factor (b‐FGF). It was found that NaCS with maximum O‐6‐sulfation and intermediate to high O‐2‐sulfation was able to bind b‐FGF comparable to natural heparin. Products being sulphated and afterwards carboxymethylated at all three positions were also able to bind substantial quantities of b‐FGF
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