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We report the synthesis, crystal structure and magnetic properties of a new heteronuclear polymeric complex based on non-Kramers Tb ions and carboxylic α-fur = C4H3OCOO ligands: {[Tb2Ba(α-fur)8(H2O)4]·2H2O}n. The α-furoate ligands consolidate 1D zig-zag chains running along the c-axis, formed by Tb2 dimers separated by Ba ions. Ab initio calculations, in combination with the fit of experimental data, predict that the single-ion magnetic ground state is highly anisotropic () and consists of a quasi-doublet with a ΔTb/kB = 3.22 K gap, well separated from the next excited state, while the gap for the Tb2 dimer is Δ2Tb/kB = 2.58 K. Static magnetization and heat capacity measurements show that, magnetically, the system can be modeled as dimers of non-Kramers Tb ions, coupled by an antiferromagnetic intradimer interaction J'*/kB = -1.6 K. Dipolar interactions couple the Tb ions in the dimer with their first neighbour ions along the chain, with J''*/kB = -0.15 K, and with the surrounding ions out of the chain, with maximum J'''*/kB = -0.03 K. Ac susceptibility measurements in H = 0 performed down to 50 mK temperatures have enabled us to observe slow relaxation of magnetization, with an Orbach-like activation energy of U/kB = 1.1 K. It is assigned to the sluggish response of the 3D spin system due to a short-range ordering, possibly enhanced by the presence of disorder caused by defects in the polymeric chains. Under the application of a magnetic field, the system slowly relaxes by two distinct direct processes, strongly affected by a phonon bottleneck effect. We discuss the different relaxational phenomenology of the new complex in comparison with that of the isostructural {[Dy2Ba(α-fur)8(H2O)4]·2H2O}n, differing only in the Kramers nature of the ions, and the mononuclear {Ln(α-fur)3(H2O)3}n (Ln = Tb, Dy) complexes, previously reported.
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INTRODUCTION: In recent years, the increase of the consumption of supplements reveals problems concerning the safety of use. Current legislation states that supplements must be free of any therapeutic purpose and must have quality guarantees for the users' safety. The operators of the of Hygiene, Food and Nutrition Service (SIAN) of ASL TO 3 (province of Turin) conducted a surveillance in order to asses the situation on the territory, to know the use and consumption in local gyms. During the official control at the manufacturers / packers of supplements, located on the territory of the ASL TO 3, labels of supplement produced / packed were acquired, to analyze the components indicated, to carry out a deep evaluation of the individual product . METHODS: Updating of the register of companies located in the territory of the ASL TO 3 was carried out; and during the period October 2011-March 2013 the labels of the products of these companies have been found and analyzed. The detailed content of the labels (ingredients, dose, method of recruitment, composition, etc. ..) was written in a database. It was also checked how many local gyms marketed supplements, and, in a small sample, a questionnaire was administered to visitors, in order to assess consumption. RESULTS: 355 labels were acquired and loaded on the database. 80% of them falls within the category of supplements based on ingredients derived from plants or similar. For these products was evaluated the presence on the label of not allowed plant extracts (according to the Ministerial Decree of 9 July 2012): only 2 products (of the same company) contained an ingredient not allowed. In all the examined labels was evaluated the presence of the substances for which there are specific warnings: 97% of the label is compliant and 3% are not in compliance. In the analyzed products the indications for use mainly found on the labels are related to increased demand and/or reduced intake, followed by antioxidant action. The study also evaluated the sale of supplements at gyms located on the territory of ASLTO3: 59 gyms are available on territory, but only in one of them supplements are sold. Some customers of these gyms have filled a questionnaire concerning the consumption of supplements. The processing of the questionnaires showed that 27% of respondents in the past 2 years used only occasionally food supplements. For 42% of the subjects the use of these products was to achieve weight loss, for 33% for athletes and 17% have used specific products in the case of particular physiological situations such as pregnancy and lactation. The reasons that lead to the use of dietary supplements, in all cases, are attributed to the improvement of health status. In addition, in 50% of cases the pharmacist has led to the use of these products or, alternatively, friends and relatives. The general practitioner is often not informed even in case of disturbances introduced after their use (seen in 8% of our sample). The majority of the sample (58%) said that they had benefited from the use of supplements and they are aware (68%) that there could be contraindications. CONCLUSIONS: A greater knowledge of the topic, with attention focused on the entire supply chain of the product, is essential to ensure the safety of consumers in the use of food supplements. For these reasons a more detailed check on the procedure is essential: selection and verification of suppliers (especially for raw materials coming from Eastern countries, because they are not subjected to a thorough inspection); traceability of products marketed; correspondence between manufactured and authorized products. Finally, promote an awareness campaign at all levels is necessary, including general practitioners for a conscious purchase.
