A Spin Resonance Investigation of Magnetism and Dynamics in the Charge-transfer Salts β"-(BEDT-TTF)4[(H3O)M(C2O4)3]S

We report a spin resonance study of the family of quasi-two-dimensional organic (super)conductors β”-(BEDT-TTF)₄[(H₃O)M(C₂O₄)₃]S, where M is a 3d transition metal ion and S is a host solvent molecule. The spin systems for M = Cr³⁺ (S = 3/2) and M = Fe³⁺ (S = 5/2) are investigated by means of both resonant and field modulation techniques in the frequency range between 50 and 313 GHz. The role of the different solvent molecules in determining the degree of spin-orbit coupling and the local symmetry at the metal ion site is established. The low temperature behaviour of intensities, positions and widths of the resonant lines shows significant modifications of the spin-orbit coupling, and of the inter-and intra-ionic spin-spin inter actions. Despite the onset of a weak antiferromagnetic internal field at low temperature, the ultimate narrowing of the lines suggests spin-lattice interactions may still be the dominant relaxation process. Diamagnetic screening in the mixed state of the superconducting samples for fields parallel to the quasi-two-dimensional layers induces additional lineshifts only below B = 2.5T and T = 4K, determining the threshold of full field penetration within the anion layers.     

Follow-up report on a randomized controlled trial of laser laparoscopy in the treatment of pelvic pain associated with minimal to moderate endometriosis

OBJECTIVE: To assess the longer term efficacy of laparoscopic laser surgery in the treatment of painful pelvic endometriosis and to observe the natural history of the disease at second-look laparoscopy in a control group. DESIGN: One-year follow-up of a prospective, randomized, double-blind controlled trial. SETTING: A referral center for the laparoscopic laser treatment of endometriosis. PATIENT(S): Sixty-three patients with pelvic pain and minimal to moderate endometriosis. INTERVENTION(S): After the 6-month follow-up visit, the randomization code was broken, and follow-up was continued to 1 year. Symptomatic patients were offered second-look laser laparoscopy. MAIN OUTCOME MEASURE(S): Continued symptom relief at 1 year after treatment and findings at second-look laparoscopy in symptomatic controls. RESULT(S): Symptom relief continued at 1 year in 90% of those who initially responded. All symptomatic controls had a second-look procedure, with 7 (29%) showing disease progression, 7 (29%) showing disease regression, and 10 (42%) having static disease. CONCLUSION(S): The benefits of laser laparoscopy for painful pelvic endometriosis are continued in the majority of patients at 1 year. Untreated painful endometriosis will progress or remain static in the majority of patients but will spontaneously improve in others.     

Copolymerization via zwitterion

Summary Copolymers of 2-methyl-2-oxazoline and phtalic anhydride without initiator were prepared at 60°C in DMF, CH₃CN and in bulk. The copolymers were statistical rich in 2-methyl-2-oxazoline and the -COCH₃ groups are partially hydrolized. The composition and the degree of hydrolysis of the copolymers were determined by ¹H-NMR. ¹³C-NMR proved that the hydrolisis did not occur during the polymerization process. A scheme of copolymerization via zwitterion is presented.     

Genesis of “Solitary Cations” Induced by Atomic Hydrogen

Substitution of constituent atoms and/or changes of crystal structure are routinely used to tailor the fundamental properties of a semiconductor. Here, it is shown that such a tailoring can also be realized thanks to a novel hydrogen effect. Four hydrogen atoms can screen the effect the crystal potential has on a constituent cation, thus generating a solitary cation: an effectively isolated impurity, so chemically different from the unscreened constituent cations that it strongly perturbs the electronic properties of the material by increasing its fundamental band‐gap energy. Such a hydrogen‐induced screening effect is removed by thermal treatments, thus permitting reversible modifications of both the “crystal chemistry” and material's properties. This phenomenon, observed in InN and other topical nitrides, should permit the development of a new class of materials as well as the fabrication of photonic devices and optical integrated circuits with distinct, tailor‐made regions emitting or absorbing light, all integrated onto a monolithic semiconductor structure.     

Poly[N-(hydroxyethyl)ethyleneimine-co-phenyl succinic anhydride] Synthesis and structure

Summary Five copolymers from N-(hydroxyethyl)ethyleneimine as nucleophilic monomer and phenylsuccinic anhydride (PhSAn) as electrophilic monomer, were synthesized according to the spontaneous copolymerization concept. These copolymers were characterized by elemental analysis, FT-IR, ¹H-NMR, and ¹³C-NMR spectroscopy. The copolymer composition determined from the ¹H-NMR spectra showed that the copolymers are not alternating. According to all the data, it was suggested a copolymer structure which includes ester and anhydride bonds. The molecular weights determined by vapor pressure osmometry ranged between 5.100 and 6.100 g/mol. Received: 12 February 1999/Revised version: 5 October 1999/Accepted: 5 October 1999     

Growth and kinetics of Lactobacillus plantarum in the fermentation of edible Irish brown seaweeds

The aim of the present study was to see the applicability of using brown edible seaweeds as a sole source of nutrition for the growth of lactic acid bacteria. Growth kinetics of lactic acid bacteria (LAB; Lactobacillus plantarum) was studied using three species of edible Irish brown seaweeds Himanthalia elongata, Laminaria digitata and Laminaria saccharina. As part of the screening process, growth of the LAB was carried out on raw and heat treated forms of seaweeds. The seaweed species in their raw state could not support the growth of L. plantarum. Heat treatment resulted in almost 4 times increase in the total sugar content in L. digitata and L. saccharina broth which allowed the growth of L. plantarum for 24 h after which the cell number started decreasing. The Laminaria spp. contains a high content of laminaran polysaccharide which can be fermented by LAB. In case of H. elongata, neither raw nor heat treated forms could be fermented; even though the total sugar content increased 4.6 times upon the application of heat. Kinetics of cell growth, lactic acid and acetic acid production was evaluated at different agitation rates in heat treated seaweeds. A maximum log CFU/ml of 10 was achieved at the end of 16-24 h of fermentation for L. saccharina and L. digitata, respectively. The cell growth increased and lactic acid accumulation decreased as the agitation speed was increased from 0 to 100 rpm. Maximum lactic acid accumulation of 2.5 g/l was achieved under static (0 rpm) conditions. The production of acetic acid was very minimal during the entire course of fermentation. Experimental data was mathematically modelled to optimize the cell growth and lactic acid production with respect to the different rotation conditions. The results of this study present an indication of the potential of fermentation of seaweeds using LAB with a possibility towards the development of a range of functional foods.     

Retention properties of efficient adsorbent to silver(I)

The binding capability of crosslinked poly(acrylic acid‐co‐2‐acrylamide‐2‐methyl‐1‐propane sulfonic acid) for silver(I) ions by the batch equilibrium method is investigated. The effects of the pH, temperature, time of contact, and resin–metal ion molar ratio on the retention ability are studied. The retention for silver(I) increases from 21.7% at pH 1 to 94.6% at pH 5. The adsorption capacity at pH 5 is 1.18 meq/g dry resin. The maximum load capacity at the optimum pH is determined. In order to recover the resin, elution runs in acid and basic media are carried out. The best eluent is 4M HNO₃ (84.9%). Moreover, retention–elution cycles are performed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1501–1506, 2002     

Interaction of heavy metal ions with an ion exchange resin obtained from a natural polyelectrolyte

An ion exchange resin was synthesized by using a natural polyelectrolyte, sodium alginate, and barium ion as a cross-linker reagent. Resin was characterized by TGA and SEM. Equilibrium and kinetic experiments of Pb²⁺, Hg²⁺, Ni²⁺, Co²⁺, Fe²⁺, and Fe³⁺ ions uptake by barium alginate beads were carried out in batch-type experiments under different values of pH. The removal efficiency increases with increasing pH. The uptake of metal ions occurs rapidly in the first hour. Maximum retention capacity was also determined being Fe(II) > Fe(III) > Co(II) > Ni(II) > Pb(II) > Hg(II) in mmol/g dry beads basis. Elution from the loaded resins at maximum capacity was studied by using HCl and HNO₃ as eluents at different concentrations.     

Liquid phase equilibrium of phenol extraction from bio-oil produced by biomass pyrolysis using thermodynamic models

Utilization of biomass as a new and renewable energy source is being actively conducted by various parties. One of the technologies for utilizing or converting biomass as an energy source is pyrolysis, to convert biomass into a more valuable product which is bio-oil. Bio-oil is a condensed liquid from the vapor phase of biomass pyrolysis such as coconut shells and coffee shells. Biomass composition consisting of hemicellulose, cellulose, and lignin will oxidize to phenol which is the main content in bio-oil. The total phenolic compounds contained in bio-oil are 47.03% (coconut shell) and 45% (coffee shell). The content of phenol compounds in corrosive bio-oils still quite high, the use of this bio-oil directly will cause various difficulties in the combustion system due to high viscosity, low calorific value, corrosivity, and instability. Phenol compounds have some benefits as one of the compounds for floor cleaners and disinfectants which are contained in bio-oil.The correlation between experimental data and calculations shows that the UNIQUAC Functional-group Activity Coefficients (UNIFAC) equilibrium model can be used to predict the liquid–liquid equilibrium in the phenol extraction process of the coconut shell pyrolysis bio-oil. While the Non-Random Two Liquid (NRTL) equilibrium model can be used to predict liquid–liquid equilibrium in the extraction process of phenol from bio-oil pyrolysis of coffee shells.