Biomedical subjects

J Orduna

Publications and source records attributed to J Orduna.

6 recordsLinked to original sources

PubMed2001

Tetrathiafulvalene derivatives as NLO-phores: synthesis, electrochemistry, Raman spectroscopy, theoretical calculations, and NLO properties of novel TTF-derived donor-pi-acceptor dyads.

Novel pi-conjugated donor-acceptor chromophores, based on the strong electron-donating tetrathiafulvalene moiety and different electron-withdrawing acceptors, exhibit large second-order optical nonlinearities. The effect of increasing the length of the polyenic spacer and the influence of the nature of the acceptor moiety on the NLO properties have been studied by using the electric field-induced second-harmonic generation (EFISH) technique as well as by semiempirical and ab initio theoretical calculations. A charge-transfer band has been observed in the absorption spectra of these D-pi-A compounds that undergoes an hypsochromic shift when increasing the number of vinylenic spacer units connecting both donor and acceptor moieties. The degree of the intramolecular charge transfer from the donor to the acceptor has also been analyzed by means of Raman spectroscopy.

Journal Article↗

PubMed2001

Tetrathiafulvalene crowns: redox-switchable ligands.

A series of redox-responsive ligands that associate the electroactive tetrathiafulvalene core with polyether subunits of various lengths has been synthesized. X-ray structures are provided for each of the free ligands. The requisite structural criteria for reaching switchable ligands are satisfied for the largest macrocycles, that is, planarity of the 1,1',3,3'-tetrathiafulvalene (TTF) pi system and correctly oriented coordinating atoms. The ability of these ligands to recognize various metal cations as a function of the cavity size has been investigated by various techniques (LSIMS, 1H NMR, and UV/Vis spectroscopy, cyclic voltammetry). These systems exhibit an unprecedented high coordination ability among TTF crown ethers. Their switchable ligating properties have been confirmed by cyclic voltammetry, and metal-cation complexation has been illustrated by X-ray structures of three of the corresponding metal complexes (Pb2+, Sr2+, and Ba2+). Solid-state structures of these complexes display original packing modes with channel-like arrangements.

Journal Article↗

PubMed2001

School health services and community nutrition: a historical perspective.

The Bilbao School Health Service was created at the beginning of the century with the aim of preventing transmittable diseases among children as well as improving nutrition. At that time such services were established in many other countries. Since then, according to evolving societal changes and emerging needs, the Service has reoriented its scope and structure towards the Health Promotion scheme. Current tasks include health screening examinations and hygiene surveillance as well as preventive and health education programmes.

Adolescent↗

PubMed2001

Community-based programme to promote physical activity among elderly people: the GeroBilbo study.

BACKGROUND: Physical activity in the elderly contributes to maintain muscle function and tone, mobility of joints and fosters social relationships when practised in a social setting, thus contributing to physical, psychological and social well-being. OBJECTIVE: To assess objective and perceived health of elderly people involved in the physical activity programme of Bilbao. DESIGN: Community-based cross-sectional study. Study protocol considered length of involvement in the programme; age, gender, perceived health, remarkable facts in personal and family disease history, as well as consumption of pharmaceutical drugs, tobacco, alcohol and physical activity (n=1500). In a subsample, (n=596; 122 men and 474 women), age range 60 to 89 years, anthropometrical measurements were collected. RESULTS: A considerable proportion (69%) had an active lifestyle and practised other physical exercise or sports, apart from the programme gymnastic sessions. Improvement in physical well-being, entertainment and social contacts were key motivations to participate in the programme. About 70% of the sample had been involved in the programme at least for three years. Mean weight was 75.8 +/-10 kg for men and 66 +/- 9.14 kg for women; mean height was 164.6 +/- 6.5 cm for men and 153 +/- 5.5 cm in the female subgroup. Body Mass Index was (BMI) 27.8 +/-2.8 kg/m2 in the male group and 28.1 +/- 3.6 kg/m2 among females. Prevalence of obesity (BMI > or = 30) was 22.7% for men and 28.9 % for women. CONCLUSION: Community interventions targeted to the elderly with a focus in physical activity, particularly when they are based in group physical exercise and implemented through existing networks are rewarding for old people and highly accepted. They are perceived as a positive influence in their health. Such interventions provide a forum which facilitates implementation of other community health initiatives addressed to this population group.

Activities of Daily Living↗

PubMed2000

Efficient charge separation in C60-based dyads: triazolino

Triazoline[4,5][60]fullerenes are strong electron acceptors that form with tetrathiafulvalene (TTF), a novel type of donor-acceptor dyad exhibiting efficient improved electron-transfer dynamics. In particular, a rapid photoinduced intramolecular electron transfer, forming a charge-separated state, is followed by a slow charge recombination to generate the fullerene triplet excited state in moderate quantum yields.

Journal Article↗

PubMed2000

pi conjugation across the tetrathiafulvalene core: synthesis of extended tetrathiafulvalene derivatives and theoretical analysis of their unusual electrochemical properties

A series of extended tetrathiafulvalene (TTF) derivatives bearing one or two 1,4-dithiafulven-6-yl substitutents has been prepared. The new compounds present remarkable electrochemical singularities compared with other TTF derivatives, which are strongly affected by the nature of the substitution on the lateral heterocycle(s). This unusual electrochemical behaviour follows a square-scheme sequence and is attributed to structural changes upon oxidation of the pi-donating molecules. Digital simulations of the electrochemical data have been used to reach the values of the kinetic and thermodynamic constants involved in the square scheme. Theoretical calculations establish an important contribution of a highly delocalised resonant form involving a tetravalent sulphur in oxidised species, which could justify the occurrence of an electrochemical behaviour distinct from that of TTF. Finally, third-order susceptibilities chi 3 of two of these systems, for which electron-donating and electron-withdrawing substituents coexist and are conjugated through the TTF pi system, are given.

Journal Article↗