The difficulties in synthesizing phase pure BiFeO3 are well known. In this letter we are reporting the optimized synthesis conditions for obtaining phase pure BiFeO3 ceramic. The oxide mixing technique followed by leaching with dilute nitric acid has been used for the synthesis. X-ray diffraction pattern indicated that the sample is phase pure. Scanning electron microscopy along with energy dispersive x-ray fluorescence analysis confirmed the chemical homogeneity of the sample. No segregation of the impurity phase in the matrix was detected. Moreover, Bi/Fe atomic ratio is observed to be ∼1. The ferroelectric transition of the sample at 836 °C has been detected by differential thermal analysis.
The likelihood of rupture of unruptured intracranial aneurysms that were less than 10 mm in diameter was exceedingly low among patients in group 1 and was substantially higher among those in group 2. The risk of morbidity and mortality related to surgery greatly exceeded the 7.5-year risk of rupture among patients in group 1 with unruptured intracranial aneurysms smaller than 10 mm in diameter.
Dielectric, magnetic, and magnetoelectric properties of Ti substituted bismuth ferrite (BiFeO3) ceramic synthesized by solid state reaction are reported. Ti substitution for Fe in BiFeO3 increased the room temperature electrical resistivity by approximately six orders of magnitude and also increased the dielectric constant and reduced the loss tangent. The remanent polarization, coercive field, and maximum polarization were 0.081μC∕cm2, 2.571kV∕cm, and 0.658μC∕cm2, respectively at 20kV∕cm. An anomaly in the dielectric constant and loss tangent around Néel temperature was observed. The ferroelectric and magnetic hysteresis loops were measured which are not really saturated in BiFe0.75Ti0.25O3 compound and represented a partial reversal. The magnetoelectric coupling between electric dipoles and magnetic dipoles at room temperature was demonstrated by measuring the effect of magnetic poling on ferroelectric hysteresis loop and the change in the dielectric constant with the external magnetic field.
Psychological distress is common in the terminally ill. It is often underdetected and undertreated and has significant impact on the individual and family. There is a growing consensus on a broader concept of psychological suffering conceptualized as "distress" in the palliative care setting. Psychological screening programs play an important role in improving detection and management of distress. National and international guidelines recommend routine screening. This systematic review summarizes the evidence for screening for psychological distress in a palliative care setting. The review includes studies that compare screening questionnaires against a gold standard criterion of semistructured or structured psychiatric interview. Eight studies were identified which examined the performance of 10 screening questionnaires, ranging from single items to multidimensional questionnaires with up to 33 items. The performances of these questionnaires are described in terms of their sensitivity, specificity, and positive and negative predictive values. There are very few studies that examine the validity of questionnaires against credible criteria such as psychiatric interview and most studies have so far focused on depression. Unidimensional scales appear to perform equally well compared to the longer versions. This review summarizes the evidence, the quality of this evidence, and future challenges to improve identification and management of distress in palliative care.
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