Dielectric spectroscopy studies of aqueous ionic solutions ACl/H, 0 (A = Li, Rb, Cs) were carried out at frequencies between 45 MHz and 20 GHz, using recently developed coaxial measurement techniques. The behavior of the static dielectric constant es0 and the dielectric relaxation time Q-, of the solutions were studied as functions of ion size and concentration. For moderate concentrations both es0 and r, decrease linearly with solution conductivity. While the behavior of gso can be understood in terms of either static or Hubbard-Onsager kinetic polarization models, the experimental results for 7. are at present not understood quantitatively in terms of these models. However we point out the good correlation of the 7. data with empirical viscosity results, which suggests an alternative explanation based upon the solution viscosity, modified by ion size effects, which play an important role in the dielectric response. We also discuss the various length scales relevant to dielectric and conductivity processes in the solutions.Dielectric spectroscopy can be a powerful probe of microscopic processes in a liquid, particularly when carried out over a broad range of frequency. The frequency dependence of the dielectric function e(w) of a liquid (pure, solution or mixture), reflects the dynamic response of the constituents of the liquid, whether ionic or dipolar.'-3 An ionic solution may be considered to consist of 3 constituents: the charged anions and cations, "hydration" solvent molecules near the vicinity of the ions, and "free" solvent molecules. At high concentration, an additional component may exist in the form of ion pairs due to incomplete dissociation.4'5 The distinction between the hydration and free solvent molecules is largely a matter of the time scales involved, and the strength of the ion-solvent interaction. Furthermore, the dynamical processes are affected by the ion size and charge. These aspects are some of the issues addressed in this work.While ionic conductivity and viscosity has been the subject of intense research,6 the dynamic aspects of the dielectric properties of ionic solutions have received less attention. Certain phenomena, such as the (static) dielectric decrement, are well known.' Reliable experimental data on the dynamic aspects, such as the relaxation time TV, have not been easily available, partly because of the higher frequencies required ( -10 GHz) particularly for aqueous solutions. In this paper we present detailed studies and analysis of the dielectric spectra of AC1 (A = Li, Rb, Cs) in H,O. The complex dielectric functions E(O) = E)(w)k" (w) were measured between 45 MHz and 20 GHz at 25 C, using recently developed techniques8*9 which enables the measurement of continuous spectra in this frequency range. E' and (T = E"WE" (E, = 8.85 X 10 -'* F/m) vs frequency for RbCl/H,O for various concentrations are shown in Figs.

Detailed measurements of the complex dielectric function ε=ε′−iε″ as functions of frequency between 45 MHz and 20 GHz and concentration c are presented and analyzed for LiCl/H2O solutions. In this frequency range, the dielectric response is due to free water molecules and the response of the bound water occurs at lower frequencies and is not observed. From the data, several parameters—the static and high frequency limiting values ε0 and ε∞, the dc conductivity σdc, the dielectric relaxation time τd, and the hydration number nhyd—are extracted. The dissociation is observed to be incomplete suggesting the presence of undissociated ion pairs. A dissociation parameter is inferred from the σdc data. A model which views the liquid as composed of free water, hydrated single ions, and hydrated ion pairs is used to analyze the ε0 data. With inclusion of the dissociation parameter, the model describes the data reasonably well for c≤5.1 M. At higher concentrations, a unique relaxation time is not observed indicating glasslike behavior.

BackgroundWhether hypothyroidism is an independent risk factor for cardiovascular events is still disputed. We aimed to assess the association between hypothyroidism and risks of cardiovascular events and mortality.MethodsWe searched PubMed and Embase from inception to 29 February 2016. Cohort studies were included with no restriction of hypothyroid states. Priori main outcomes were ischemic heart disease (IHD), cardiac mortality, cardiovascular mortality, and all-cause mortality.ResultsFifty-five cohort studies involving 1,898,314 participants were identified. Patients with hypothyroidism, compared with euthyroidism, experienced higher risks of IHD (relative risk (RR): 1.13; 95% confidence interval (CI): 1.01–1.26), myocardial infarction (MI) (RR: 1.15; 95% CI: 1.05–1.25), cardiac mortality (RR: 1.96; 95% CI: 1.38–2.80), and all-cause mortality (RR: 1.25; 95% CI: 1.13–1.39); subclinical hypothyroidism (SCH; especially with thyrotropin level ≥10 mIU/L) was also associated with higher risks of IHD and cardiac mortality. Moreover, cardiac patients with hypothyroidism, compared with those with euthyroidism, experienced higher risks of cardiac mortality (RR: 2.22; 95% CI: 1.28–3.83) and all-cause mortality (RR: 1.51; 95% CI: 1.26–1.81).ConclusionsHypothyroidism is a risk factor for IHD and cardiac mortality. Hypothyroidism is associated with higher risks of cardiac mortality and all-cause mortality compared with euthyroidism in the general public or in patients with cardiac disease.Electronic supplementary materialThe online version of this article (doi:10.1186/s12916-017-0777-9) contains supplementary material, which is available to authorized users.

Background: The purpose of this study is to evaluate the status quo and factors that influence the preferences of the elderly for the combination of medical care and pension (CMCP) in long-term care (LTC) facilities and to provide an evidence-based basis for building a multi-tiered, continuous LTC system with CMCP. Methods: Using a multi-stage sampling method, face-to-face questionnaire surveys were conducted on 3260 elderly people aged 60 years or over in 44 communities in 16 sub-districts in six districts in Xiamen. Based on the Andersen model, the chi-square test was used to analyze differences in population distribution, and binary logistic regression analysis was used to analyze the factors affecting the elderly’s preference for CMCP in LTC institutions in terms of the factors of predisposition, enablement, and personal needs. Results: Most elderly people choose traditional home care (82.01%), and only 12.89% choose LTC facilities with CMCP. This choice is influenced by a number of predisposing factors. The elderly who are at the upper end of the age range, have a higher education level, and live in rural areas are more likely to choose CMCP (odds ratio (OR) value greater than 1, p < 0.05). With regard to enabling factors, the elderly who were married, mainly taken care of by spouses, and had better economic status also tended to choose CMCP (OR > 1, p < 0.01). In terms of personal needs, the elderly with worse self-care status tended to choose CMCP (OR > 1, p < 0.01). Enabling factors have the largest contribution to the model, and they have the greatest impact on elder preference for CMCP services. In addition, the elderly with higher age and education level, non-remarried, with better economic status, and with poorer health status have a demand for a wider variety of CMCP services. Compared to those in urban areas, the elderly in rural areas have greater needs, mainly related to personal care, medical care, and psychological counseling. Conclusion: The preference of the elderly for CMCP are lower compared to their preference for home care in Xiamen, China. Preference for CMCP is affected by a range of factors such as age, education level, residence, income, and self-care ability, among which the enabling factors have the greatest impact.