Hydrothermal-Assisted Cold Sintering Process: A New Guidance for Low-Temperature Ceramic Sintering

Sintering is a thermal treatment process that is generally applied to achieve dense bulk solids from particulate materials below the melting temperature. Conventional sintering of polycrystalline ceramics is prevalently performed at quite high temperatures, normally up to 1000 to 1200 °C for most ceramic materials, typically 50% to 75% of the melting temperatures. Here we present a new sintering route to achieve dense ceramics at extraordinarily low temperatures. This method is basically modified from the cold sintering process (CSP) we developed very recently by specifically incorporating the hydrothermal precursor solutions into the particles. BaTiO₃ nano polycrystalline ceramics are exemplified for demonstration due to their technological importance and normally high processing temperature under conventional sintering routes. The presented technique could also be extended to a much broader range of material systems than previously demonstrated via a hydrothermal synthesis using water or volatile solutions. Such a methodology is of significant importance, because it provides a chemical roadmap for cost-effective inorganic processing that can enable broad practical applications

Protocol for Ultralow-Temperature Ceramic Sintering: An Integration of Nanotechnology and the Cold Sintering Process

The sintering process is an essential step in taking particulate materials into dense ceramic materials. Although a number of sintering techniques have emerged over the past few years, the sintering process is still performed at high temperatures. Here we establish a protocol to achieve dense ceramic solids at extremely low temperatures (<200 °C) <i>via</i> integrating the particle nanotechnology into the recently developed cold sintering process (CSP). The sintering path has been appropriately tailored <i>via</i> effectively utilizing the large surface-to-volume ratio of nanoparticles. BaTiO₃ ceramics have been used for the illustration, given its importance in extensive electronic device applications, as well as its scientific interest, being a model material for many of the ferroelectric materials. Together with detailed experimental studies, the trends are also analyzed with a fundamental thermodynamic consideration. Such an impactful technique could have widespread application prospects in a wide variety of materials and would also provide a clear roadmap to guide future studies on ultralow-temperature ceramic sintering, ceramic materials related integration, and sustainable manufacturing practices

Effect of the Prosthetic Group on the Pharmacologic Properties of ¹⁸F‑Labeled Rhodamine B, a Potential Myocardial Perfusion Agent for Positron Emission Tomography (PET)

We recently reported the development of the 2-[¹⁸F]­fluoroethyl ester of rhodamine B as a potential positron emission tomography (PET) tracer for myocardial perfusion imaging. This compound, which was prepared using a [¹⁸F]­fluoroethyl prosthetic group, has significant uptake in the myocardium in rats but also demonstrates relatively high liver uptake and is rapidly hydrolyzed in vivo in mice. We have now prepared ¹⁸F-labeled rhodamine B using three additional prosthetic groups (propyl, diethylene glycol, and triethylene glycol) and found that the prosthetic group has a significant effect on the in vitro and in vivo properties of these compounds. Of the esters prepared to date, the diethylene glycol ester is superior in terms of in vitro stability and pharmacokinetics. These observations suggest that the prosthetic group plays a significant role in determining the pharmacological properties of ¹⁸F-labeled compounds. They also support the value of continued investigation of ¹⁸F-labeled rhodamines as PET radiopharmaceuticals for myocardial perfusion imaging

Cold Sintering Na₂Mo₂O₇ Ceramic with Poly(ether imide) (PEI) Polymer to Realize High-Performance Composites and Integrated Multilayer Circuits

The cold-sintering process is utilized to fabricate ceramic–polymer (Na₂Mo₂O₇-poly­(ether imide), PEI) composites and integrated multilayer circuits. The Na₂Mo₂O₇-PEI bulk composites cold-sintered at 120 °C show high densities (>90% theoretical). The permittivity at microwave frequencies decreases with increasing PEI content, following the classical logarithmic mixing law, and <i>Qf</i> values show no deterioration with the addition of PEI. Furthermore, the characteristic dielectric breakdown strength of the ceramic–polymer composite obtained from a Weibull plot increases dramatically from 55.1 to 107.5 MV/m with 10–20 vol % PEI additions. In the case of high PEI content where there is more segregation of the polymer within the ceramic matrix, there is a gradual decrease in the dielectric breakdown strength. Na₂Mo₂O₇-PEI-Ag bulk ring resonators can be obtained by post screen printing, and the mixing laws are used to calculate the permittivity of the ring resonators. As a prototype of integrated multilayer circuits, Na₂Mo₂O₇-PEI-Ag multilayer ring resonators with good microwave dielectric properties can be successfully densified by cold-sintered cofired ceramic-composite technology at 120 °C without delamination or warping, demonstrating the feasibility of cold sintering in the ceramic–polymer composite integrated multilayer circuits

Additional file 1: of Electronic nicotine devices to aid smoking cessation by alcohol- and drug-dependent clients: protocol for a pilot randomised controlled trial

SPIRIT checklist. (DOC 121 kb

Additional file 1: of Improving cardiovascular health and quality of life in people with severe mental illness: study protocol for a randomised controlled trial

SPIRIT 2013 Checklist: Recommended items to address in a clinical trial protocol and related documents*. (DOC 125 kb

Additional file 2: of Improving cardiovascular health and quality of life in people with severe mental illness: study protocol for a randomised controlled trial

Table S1. The Flinders Program Tools. (DOCX 16 kb

Additional file 2: Table S6. of Help-seeking for mental health problems by employees in the Australian Mining Industry

Workplace factors and attitudes associated with professional and non-professional help seeking (n = 1,319). (DOC 97 kb

Additional file 1: of Help-seeking for mental health problems by employees in the Australian Mining Industry

Survey. (DOC 377 kb

Additional file 1: of Study protocol for a systematic review of evidence for lifestyle interventions targeting smoking, sleep, alcohol/other drug use, physical activity, and healthy diet in people with bipolar disorder

Systematic review data extraction form. (PDF 75 kb