COF Groups Research Articles

Profile of F2-Isoprostane Level After 5-Day Administration of Robusta Coffee at a Steady State Dose in Subjects Performing Physical Exercise

This study aims to analyze the effect of robusta Dampit coffee on F2-isoprostane levels influenced by ROS due to excessive exercise. This study was an experimental study with a pre- and post-test control group design with coffee administration. The total sample was 18 untrained or sedentary male, divided into two groups: coffee group (COF, n=9) and control/placebo group (PLB, n=9). The COF group was given 2 cups of filtered coffee a day (100 ml/cup) at 12-hour intervals for 5 days. Both groups performed physical exercise with a step test on day 6. Blood samples were collected pre and two hours post exercise. F2-isoprostane concentration was analyzed using the F2-isoprostane biomarker and ELISA to measure the level of lipid peroxidation. Results showed a decrease in F2-isoprostane levels in both COF (pre: 1531.57±278.13 pg/mL; post: 1367.6±230.24 pg/mL; p=0.110) and PLB (pre: 1716.65±501.19 pg/mL; post: 1600.02±500.59 pg/mL; p=0.139) groups with a greater decrease in the COF group. However, this reduction was not significantly different between groups (p=0.734). Although not significantly different, exercising participants tended to have lower F2-isoprostane levels after consuming robusta coffee for five days at a steady state dose. Therefore, further investigation is needed to ascertain the physiological consequences of coffee administration over a longer period of time and its effect on recovery speed. Keywords: coffee, exercise, lipid peroxidation, and F2-isoprostane

Effects of dietary Ampithoe sp. supplementation on the growth, energy status, antioxidant capacity, and ammonia-N tolerance of the shrimp Litopenaeus vannamei: Continuous versus interval feeding

A 48-day feeding trial and an acute ammonia-N stress test were performed to investigate the effects on the growth performance, energy status, antioxidant status, and ammonia-N tolerance of Litopenaeus vannamei (5.0 ± 0.2 cm, 1.6 ± 0.4 g) when commercial feed was supplemented with freeze-dried powder of Ampithoe sp. (FDPA) on an interval and a continuous schedule. Shrimp fed with commercial feed were defined as the control group. For the interval feeding group (INF group), commercial feed supplemented with FDPA was provided once every 4 days, while commercial feed was used on the remaining days. The continuous feeding group (COF group) received commercial feed with added FDPA every day. The shrimp in the INF group and COF group showed better growth performance than did the control shrimp, and the survival rate and average yield in the COF group were significantly higher than those in the control group. During the culture period, the concentrations of glucose, triglycerides and total cholesterol in the hemolymph of shrimp were generally higher in the INF and COF groups than in the control group, and the concentrations in the COF group were generally higher than those in the INF group. Compared with the control group, shrimp in the INF and COF groups had elevated glutathione peroxidase (GSH-Px) activity, total antioxidant capacity (T-AOC), and expression levels of ATPase-α and PFK in the hemolymph or hepatopancreas, along with reduced malondialdehyde (MDA) concentrations and expressions of AMPK-α and FAS in the hepatopancreas. At 48 to 192 h during the ammonia-N stress test, the concentrations of urea-N and ammonia-N in the hemolymph generally remained lower in the INF group and COF groups than in the control group. At the end of the ammonia-N stress test, the shrimp mortality rates in the INF and COF groups were 28.1% and 40.6%, respectively, which were lower than the rate of 75.0% observed in the control group. In conclusion, dietary supplementation with FDPA had a positive influence on shrimp growth performance, energy status, antioxidant status and ammonia-N tolerance, and continuous feeding appeared to be more effective than interval feeding at improving antioxidant capacity.

Training professionals to implement a group model for alleviating loneliness among older people – 10-year follow-up study

ABSTRACTBackground and objectives: Although randomized controlled trials (RCTs) have been performed to alleviate loneliness among older people, little is known about how they have been implemented, or whether they are effective in real life. Our RCT-based model, “Circle of Friends” (CoF) proved to be effective in improving the wellbeing, health and cognition of lonely older people. Over 10 years we have systematically trained 752 professional facilitators of lonely older people’s CoF groups. This study aims to explain how this training has succeeded in practice and to describe the outcomes of CoF implementation. Research Design and Methods: Survey data were gathered in 2006–2016 from trained facilitators (n = 319) and CoF participants (n = 1041). Results: The CoF has been disseminated in 80 municipalities in Finland. The trained CoF facilitators have maintained the original key elements and structure of the model fairly well in its implementation and dissemination processes. The main objectives of CoF – the alleviation of loneliness, making new friends, and members continuing meetings on their own – have remained the facilitators’ priority. The CoF socially activates older participants, as 67% organized group meetings after the facilitated process. However, the CoF has become diluted in some aspects during its dissemination, as a small proportion of trained facilitators have implemented the model in their own way. Discussion and Implications: The CoF may be an encouraging example of how an original RCT model with a rigorous training program can be implemented and disseminated in real-life settings over 10 years.

Promotion of initial swim bladder inflation and effect of initial inflation failure on skeletal malformation in cultured seven-band grouperHyporthodus septemfasciatus(Thunberg)

The effects of the removal of the oily surface film on initial swim bladder inflation and survival in cultured seven-band grouper Hyporthodus septemfasciatus were investigated during the larval stage. Additionally, the relationship between swim bladder inflation failure and malformations in later stages was examined. To explore promotion conditions for inflation, duplicate experiments were conducted under three different water surface conditions: removal of the oily surface film (ROF group), covering the water surface with an oil film (COF group), and sealing the water surface with liquid paraffin (SLP group). Larval swim bladder inflation was first observed 14 days after hatching (DAH) in the ROF group; thereafter, swim bladder inflation rates increased to 11.1% and 38.7% until the end of the experiments. This indicates that initial swim bladder inflation occurs at the pre-flexion stage in larval development. Conversely, bladder inflation was rarely observed in the COF or SLP groups, indicating the promotional effect of surface film removal on larval swim bladder inflation and suggesting that gulping atmospheric air is necessary for initial inflation. Although larval water surface death occurred frequently in the ROF group, no significant difference existed in any group between the survival rates at 10 DAH and at the end of the experiment. The incidence rate of spinal curvature and deformation of the centra was significantly higher in individuals without initial swim bladder inflation, and these malformations mainly occurred in the caudal vertebra. Therefore, the removal of the oily surface film promotes initial swim bladder inflation and reduces larval malformations.

Properties of melt processable PTFE/PEEK blends: The effect of reactive compatibilization using electron beam irradiated melt processable PTFE

AbstractFor the first time, blends of melt processable polytetrafluoroethylene (MP PTFE) with polyetheretherketone (PEEK) in the MP PTFE/PEEK ratio of 100/0, 80/20, 50/50, 20/80, and 0/100 w/w were prepared and characterized. MP PTFE/PEEK blends are attractive materials due to the combination of low coefficient of friction and universal chemical resistance of MP PTFE with good wear resistance and mechanical strength of PEEK while maintaining high thermal stability of both. Miscibility, phase morphology, and mechanical properties of the new MP PTFE/PEEK blends were investigated. To improve their end‐use properties, an attempt of reactive compounding with the electron beam irradiated MP PTFE (e‐beam MP PTFE) was made. The reactive compounding was done in two steps, that is, the preparation of a masterbatch (MB) consisting of e‐beam MP PTFE/PEEK (50/50 w/w) and subsequent melt blending of MP PTFE/PEEK with varying concentrations of MB. The e‐beam irradiation of MP PTFE carried out in air atmosphere and at room temperature with a dose of 50 kGy results in its chain scission associated with formation of COF and COOH functional groups. Such modified MP PTFE can be used to compatibilize MP PTFE/PEEK blends. Reactive compatibilized blends exhibit improved phase morphology and mechanical properties. Especially for MP PTFE/PEEK 50/50 blends, a great improvement of almost 250% in strain at break, 40% in stress at break, and more than 600% in toughness was achieved. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

FTIR equivalent weight determination of perfluorosulfonate polymers

AbstractFourier transform infrared (FTIR) and attenuated total reflectance (ATR) spectroscopy studies of the sulfonyl fluoride, potassium salt, and sulfonic acid forms of long and short side chain perfluorosulfonate polymers revealed bands indicative of the sidegroup and backbone compositions, endgroups on the main chain, water content, monomer concentration, and degree of salt hydrolysis. The equivalent weight (EW) of the polymer was obtained by titration and NMR measurements which were then calibrated to either the CF/COC absorbance band ratio for thin (<1.1 mil) films or to a CF/SO2F absorbance band ratio for thick films (5 to 25 mils). An FTIR measurement of the film thickness based on the CF group concentration was found to be both a function of the actual thickness and the EW; a method for compensating for this EW dependence is described. Esterification and fluorination of the polymers yielded FTIR measurements of the endgroup compositions on the polymer backbone which were shown to consist of COF, COOH, CO2CH3, and CFCF2 groups. Thermogravimetric Analysis Infrared (TGA‐IR) spectroscopy of the acid form polymers indicates that degradation begins by the decomposition of the SO3H group at 320°C followed by bulk deterioration above 400°C. The FTIR techniques detailed herein have been developed for accurate, reproducible, and rapid compositional measurements of Nafion® and other perfluorosulfonate polymers. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

PTFE Micropowder Functionalized with Carboxylic Acid Groups

AbstractPTFE powder irradiated in air at room temperature was studied by infrared spectroscopy, potentiometric titration with sodium hydroxide, and polyelectrolyte titration with poly(diallyl dimethylammonium chloride). Through the radiation‐induced degradation COF groups are formed in the material, which can be hydrolyzed to COOH groups. About 10–20% of the COOH groups are located at the surface of the PTFE particle. The COOH groups start to decompose under oxidizing conditions at temperatures above 200 °C. The decarboxylation results in the formation of CFCF2 groups, which are oxidized to COF groups in the presence of air.magnified image

A Grounded Theory study of Circles of Friends groups: The power of the set-up meeting as a tool for opening the social field for isolated children in schools

‘Circle of Friends’ (CoF) was originally developed in Canada as a social tool for including vulnerable children or adults within their mainstream communities (Pearpoint, Forest & Snow, 1992). Within the UK context, CoF has been increasingly introduced by schools as a strategy for including pupils, with a range of challenging needs or behaviours, who have become rejected by or isolated from their peers.The initial set-up meeting plays a critical role in establishing CoF interventions. The present paper focuses on a review of relevant qualitative and quantitative literature and a Grounded Theory analysis of a research study undertaken by the lead author. The design involved interviews with 25 facilitators of CoF within mainstream schools in a large shire county and an outer London suburb. The children participating in the CoF groups ranged in age from seven to twelve years.The psycho-social theories emerging from the analysis contribute to our understanding of the part played by the set-up meeting and ‘perspective taking’ in the initial stages of the change process.At its highest level of conceptualisation the final theory describes how a ‘Circle of Friends’ can facilitate the movement of a pupil from a ‘closed’ or isolated social field to more ‘open’, peer based, social relationships. Hypotheses for subsequent social action and future research are discussed.

The structures of new forms of polytetrafluoroethylene obtained by modification of commercial PTFE using different methods

The structures of different polytetrafluoroethylene (PTFE) powder forms—PTFE-FORUM TMobtained by thermal treatment, PTFE-TOMFLON TM obtained by irradiation and crushing in vortex mill and PTFE-F4—were investigated by means of IR, ESR, NMR and X-ray spectroscopy methods. Ab initio calculations were used for interpretation of the experimental data. All the studied PTFE forms are in general crystals with amorphous regions in their structures. The nature of amorphism in FORUM TM differs from those in PTFE-F4 and TOMFLON TM. The molecular structure of PTFE remained mostly intact in all modified forms. FORUM TM is a low-molecular form of PTFE built from helixes with terminal – CF CF 2 and branching– CF 3 groups. The terminal –COF groups emerge in the chains in the PTFE-F4 and FORUM TM structures after irradiation in air. Unlike TOMFLON TM, in which structure radicals were detected, their presence in the structures of PTFE-F4 and FORUM TM was observed only after irradiation.

Identification of new chemical structures in poly(tetrafluoroethylene-co-perfluoropropyl vinyl ether) irradiated in vacuum at different temperatures

Electron beam irradiation of perfluorinated copolymer poly(tetrafluoroethylene-co-perfluoropropyl vinyl ether) (PFA) was carried out in vacuum at different temperatures between room temperature and temperature above the melting point of PFA. Changes of chemical structure were studied by 19F solid-state NMR and IR spectroscopy. Chain scissions and branching reactions occur simultaneously, which are indicated by formation of CF 3, COF and COOH end groups, CF branching points and CF 3 side groups. Branching density based on concentration of CF groups increases with increasing temperature. Formation of cross-links is concluded for PFA irradiated in molten state. Perfluoropropyl vinyl ether (PPVE) units are found to be more sensitive to radiation than tetrafluoroethylene units. COF and COOH groups are assumed to result from PPVE degradation.

Structure–property behaviour of electron beam irradiated polytetrafluoroethylene and polytetrafluoroethylene-co-hexafluoropropylene

The effect of various doses of electron beam (EB) irradiation in air on the structure, thermal and mechanical properties of polytetrafluoroethylene (PTFE) and polytetrafluoroethylene-co-hexaflouropropylene (FEP) has been investigated. IR spectroscopic analysis of EB irradiated polymers showed an absorption band due to carbonyl group (CO) stretching as a result of irradiation and hydrolysis of the COF groups to carboxylic acid groups. While EB irradiated PTFE displayed higher thermal stability than unirradiated polymer, an opposite behaviour was observed in the case of FEP polymer as shown by thermogravimetric analysis (TGA) thermograms. However, unirradiated PTFE polymer is more stable against thermal decomposition than unirradiated FEP polymer within the same range of temperatures. The calculated activation energies of the thermal decomposition reaction for both polymers give further support to these trends and indicate that the reaction is temperature-dependent and follows zero-order kinetics. The stress–strain curves of both PTFE and FEP either before or after EB irradiation showed no yield properties. Meanwhile, exposing both polymers to a dose of 125 kGy causes a dramatic drop in stress and strain at break suggesting the occurrence of oxidative degradation during EB irradiation. However, PTFE polymer is highly sensitive to EB irradiation compared to FEP polymer exposed to the same dose.

FTi.r. spectroscopy on electron irradiated polytetrafluoroethylene

The partial degradation of polytetrafluoroethylene caused by electron irradiation was investigated by infrared (i.r.) transmission, diffuse reflectance (DR) and photoacoustic (PAS) spectroscopy. We studied the influence of the radiation dose and the hydrolysis conditions on the structure. Irradiation produces COF groups with a band at 1884 cm −1 in the transmission spectra. Under ambient conditions these COF groups hydrolyse with the atmospheric humidity to free (1810 cm −1) and associated (1776–1792 cm −1) COOH groups. We could establish the presence and the nature of these groups in near surface regions and in the bulk phase. The formation of carboxylic groups in different states of association also depends on the hydrolysis conditions. Various forms of hydrogen bonding can be found for different associated COOH groups (1776 and 1792 cm −1). Hence we could assign the band at 1776 cm −1 to the vibration of a dimer consisting of two hydrogen bonded carboxyl groups. The band at 1792 cm −1 comes from ‘monomeric’ acid groups associated with water via hydrogen bonds. After hydrolysis under extreme conditions using alcoholic sodium hydroxide changes in band intensities and a strong new band at 1784 cm −1 were observed. This fact indicates a change of association states on the surface. Subsequently ester groups were formed in a surface acylation reaction of COF groups with ethanol which give this new band. From the DR and PAS spectra it can be concluded that most COOH groups are localized in the near surface region. In every case a small part of the COF groups remains after hydrolysis. The COF band in the spectra of hydrolysed PTFE only disappears when the permeation conditions for water vapour at the PTFE surface were improved. This fact indicates that COF groups in irradiated PTFE are not only localized on the surface of the PTFE particles. The results establish the hypothesis that a part of the COF groups is inaccessibly arranged in the inner part of the irradiated PTFE particle, and spontaneous hydrolysis is preferred in near-surface regions.

Surface modification of fluoropolymers

COF groups are formed by electron irradiation of PTFE [poly(tetrafluoroethylene)] powders in air, especially at the surface and in near-surface regions which can be easily hydrolysed to carboxyl groups by air humidity. The application of special additives during irradiation leads to modified micropowders. Fourier transform infrared (FTIR) spectroscopy enables the detection of carboxyl and COF groups. γ-Irradiation of PTFE mainly causes degradation of the polymer; the concentration of carboxyl groups is much lower. Carboxylated micropowders created via radiation treatment retain the essential properties of PTFE. With increasing radiation dose, the increasing concentration of functional groups in the micropowders causes an increase in the surface free energy. This diminishes the strong water and oil repellency of PTFE in such a way that homogeneous incorporation into aqueous and organic liquids or other polymers is possible. So, the special properties of PTFE can be made effective in these media. Modified PTFE micropowders have been successfully tested in many application areas. The aim of our present work was to increase the concentration and vary the nature of functional groups by radiation-chemical methods or chemical conversion of COF groups (polymer-analogous reactions). A highly modified PTFE powder was used to reduce the repellent properties of PTFE diaphragms for application in brine electrolysis. The COF groups of the micropowders were modified by γ-aminopropyltriethoxysilane. The irradiation of FEP [poly(tetrafluoroethylene-co-hexafluoropropylene)] and PFA [poly(tetrafluoroethylene-co-perfluoroalkylvinylether)] yields products which contain a higher content of carboxyl groups than PTFE.

Gas-phase structures and conformational compositions of some fluorocarbonyl compounds.

The gas-phase structures and conformational compositions of FC(O)NCO (1), FC(O)N 3 (2), FC(O)CH 2C(O)F (3) and FC(O)CF 2C(O)F (4) were determined by electron diffraction, vibrational analyses and ab initio calculations. All four comounds exist in the gas-phase as mixtures of at least two conformers. The main conformers of (1) (70 (5)%) and (2) (90 (5)%) are characterized by cis positions of the vicinal 1,3 double bonds, the less stable formsare planar trans in both cases. In malonyl fluoride (5) the low energy conformer possesses C 1 symmetry with one COF group rotated by δ(CCCO) of 112 (2) o and the other COF group lying in the CCC plane. The presence of 10 (10)% of a second conformer with C 2 symmetry and with both CO bonds eclipsing the CH bonds is likely. The main form of difluoromalonyl fluoride (4) possesses C 2 symmetry with both COF groups rotated by 120(2) o and the high energy conformer (30 (15)%) possesses C 1 symmetry with one CO bond eclipsing one vicinal CF bond, while the other CO bond eclipses the opposite CC bond.