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SrxBa1-xNb2O6 ceramics were prepared via the high-temperature solid-state reaction method. Structural, ferroelectric, electrocaloric effect and pyroelectric energy harvesting capabilities of SrxBa1-xNb2O6 ceramics were reported. The main structural phase of tetragonal tungsten bronze with Sr-doped was detected by X–ray diffraction. It was found that the ferroelectric hysteresis loops became slimmer after the temperature higher than Curie temperature of SrxBa1-xNb2O6 ceramics, which was a representative feature of relaxor ferroelectric. In addition, we presented the positive peak values of electrocaloric at vicinity of Curie temperature which was affected by the applied electric field for all samples. It is worth noting that the pyroelectric energy harvesting property is the first time investigated by using Olsen cycle for SrxBa1-xNb2O6 ceramic. The maximum pyroelectric energy harvesting density was 170 kJ m−3 for x = 0.6 in SrxBa1-xNb2O6 with the temperature range from 293 to 433 K. The experimental results indicated that better pyroelectric energy harvesting property and larger electrocaloric effect of SrxBa1-xNb2O6 ceramic benefited from the higher Sr/Ba ratio. Finally, energy-storage capacity for SrxBa1-xNb2O6 ceramic was obtained from the ferroelectric hysteresis loop and the maximum room-temperature energy-storage efficiency was 86.37% with x = 0.6 under 60 kV cm−1.

BaCexTi1−xO3 (BCT) ceramics at x = 0.025, 0.05, 0.075 and 0.1 were prepared by the traditional solid state reaction route and sintered at 1540 °C for 6 h. The microstructural, dielectric, electrocaloric, and pyroelectric performances of BCT were systematically explored. Hysteresis loops were measured under various temperatures, and the electrocaloric effect (ECE) was calculated for all samples. The results showed that BaCe0.075T0.925O3 had the best ECE which exhibited a large adiabatic temperature change of 0.81 K, an isothermal entropy change of 0.82 JK−1kg−1 and an electrocaloric strength of ∼0.28 Km/MV. Further, the pyroelectric figure of merits (FOMs) were analyzed and the results indicated that BaCe0.1T0.9O3 would be a better candidate for pyroelectric devices which exhibited high pyroelectric coefficient (p) of 7.82 × 10−4 Cm−2K−1 and FOM of high detectivity (Fd) of 10.39 μPa−1/2. These results in this work would facilitated the development of the electrocaloric and pyroelectric performance of Ce-doped BaTiO3 ceramics.

Objective Single-dose intravenous (IV) injection of ketamine has shown rapid but transient antidepressant effects. The strategy of repeated-dose ketamine infusions to maintain antidepressant effects has received little systematic study. This study was conducted to examine the efficacy and tolerability of six ketamine infusions in Chinese patients with unipolar and bipolar depression. Methods Ninety seven patients with unipolar (n = 77) and bipolar (n = 20) depression received repeated ketamine infusions (0.5 mg/kg over 40 min) with continuous vital sign monitoring. Depressive symptoms were measured by the Montgomery-Asberg Depression Rating Scale (MADRS). Suicidal ideation was assessed using the Scale for Suicidal Ideations (SSI)-part 1. Anxiety symptoms were evaluated with the 14-item Hamilton Anxiety Scale (HAMA). Adverse psychopathological and dissociative effects were assessed using the Brief Psychiatric Rating Scale (BPRS)-positive symptoms and Clinician Administered Dissociative States Scale (CADSS), respectively. Patients were assessed at baseline, 4 and 24 h, and 3, 4, 5, 6, 8, 9, 10, 11, 12, 13 and 26 days. Results After six ketamine infusions, the response and remission rates were 68.0% and 50.5%, respectively. There were significant decreases in MADRS, SSI-part 1, and HAMA scores within four hours following the first ketamine infusion, and the decreases were sustained over the subsequent infusion period. The nonresponder subgroup manifested rapid significant improvement in suicidal ideations throughout the course of treatment. After the six ketamine infusions, the response was positively associated with the response at 24 h after the first infusion (OR = 8.94), personal income ≥4000 yuan/month (OR = 3.04), and no history of psychiatric hospitalization (OR = 3.41). Only CADSS scores had a mild but marginally significant increase after the first infusion but with a significant BPRS score decrease. Conclusion Six ketamine infusions were safe and effective in patients with unipolar and bipolar depression. The rapid and robust antidepressant and antisuicidal effects of ketamine infusion within four hours were sustained following the subsequent infusions.

Lead-free ferroelectric ceramics (1-x) BaTiO3–xBi(Mg1/2Ti1/2)O3 (x = 0.0–0.07) were synthesized by conventional solid state reaction method and the correlation of structure, dielectric, ferroelectric and impedance properties were investigated. It was found that Tm and εm showed decreasing trend with the increase of BMT content. The high-temperature dielectric relaxation behaviour was observed in all the samples. The activation energy calculated from impedance (Ea) and conductivity (Econd), which revealed that the relaxation behaviours were linked with the migration of OVs. The values of Ea were almost equivalent to Econd. It was concluded that the short-range hopping of oxygen vacancy contributed to the dielectric relaxation and long-distance movement of doubly ionized oxygen vacancies contributed to the conduction. On the other hand, with increasing BMT contents, it was found that P-E loops became slimmer and slimmer, which indicated the increase of relaxor behaviour. The temperature dependence of P-E loops for 0.98BT–0.02BMT ceramic clearly showed the transition process from ferroelectric to relaxed ferroelectrics. Keywords: BT–BMT ceramic, Dielectric, Ferroelectric, Impedance, Oxygen vacancies

The microstructure, dielectric property and electrocaloric effect were investigated in the lead-free (1-x)BaTiO3–x (BiMg1/2Ti1/2)O3 ((1-x) BT–x BMT, x = 0.0–0.05) ferroelectric ceramics. Under the low electric field (E ≤ 20 kV cm−1), the coexistence of a positive and negative electrocaloric effect was obtained in (1-x)BT–x BMT (x ≤ 0.04) ceramics system using the Maxwell relation. Negative electrocaloric behavior disappears and the positive electrocaloric effect was only observed at high electric field (E ≥ 25 kV cm−1). Firstly, the values of both negative electrocaloric effect under low electric field of E ≤ 20 kV cm−1 (NECE) and positive electrocaloric effect in the high electric field of E ≥ 25 kV cm−1 (PECE) increase, then decrease with increasing BMT content in the ceramics. The 0.98BT-0.02BMT ceramic shows the excellent PECE and NECE capabilities. The corresponding giant electrocaloric effect values of −0.37 K (42 °C) at 20 kV cm−1 and 1.21 K (143 °C) at 55 kV cm−1 were observed. These results show great potential in achieving large cooling power as refrigerants.

Recently, the energy crisis become more and more intense and people are gradually committed to new energy storage devices to ease the pressure. Composite energy storage ceramics are extensively explored for its splendid dielectric/ferroelectric performances. In this research, it is the first time that the (1 − x)BaTiO3-xBi(Mg1/2Hf1/2)O3 (BT-BMH) lead-free ferroelectric ceramics are prepared by traditional solid-state method. By introducing BMH into BT lattice, normal ferroelectric can be induced to relaxor ferroelectric. Especially in the case of high BMH doping (x ≥ 0.05), the relaxation dispersion behaviors are more obvious. As addition BMH goes up, the hysteresis loops gradually shrink to sublinear, which is conducive to the high efficiency of energy storage performance of ceramic capacitors. Meanwhile, the recoverable energy of BT–BMH (x = 0.1) ceramics can reach 3.38 J/cm3 with efficiency of nearly 87% at a relatively low electric field of 240 kV/cm. In addition, the optimized ceramic samples possess excellent stability of variable temperatures and frequencies, showing the potential for storage application.

Northern hybridization with five HERV-K family members, previously cloned from human teratocarcinoma genomic DNA, indicated that two (HERV-(K)27 and -(K)67) of the five clones are expressed in these teratocarcinoma cells. These two clones are closely related (98.49%), however, and Northern blot hybridization lacks the specificity to distinguish between their respective mRNAs. Therefore, PCR analysis with mixed oligonucleotide primers homologous to conserved retroviral pol gene regions was employed to amplify cDNA synthesized from teratocarcinoma cell RNA. This amplification scheme yielded two novel HERV-K family members, HERV-(K)55 and HERV-(K)91. Clone HERV-(K)55 has approximately 98% nucleotide sequence identity to clones HERV-(K)27 and -(K)67. Subsequent RNase protection assays confirmed the expression of HERV-(K)55 and indicated that clones HERV-(K)27 and -(K)67 were not expressed in these cells. One interpretation is that the HERV-(K)27 and -(K)67 probes detected transcripts of clone HERV-(K)55 or other closely-related elements because of their high homologies. In addition, clone HERV-(K)91, which has approximately 81% nucleotide sequence identity to clones HERV-(K)27, -(K)67, and -(K)55, was obtained only from teratocarcinoma 2102E-Pr cells, but the RNase protection assay showed that this clone is also expressed in other human teratocarcinoma cell lines.