Effect of high temperature on mechanical and physical properties of lightweight cement based refractory including expanded vermiculite

Four different composite mixtures with varying amounts of expanded vermiculite were exposed to high temperatures of 300, 600, 900 and 1100 degrees C for 6 h. Physical and mechanical properties including unit weight, porosity, water absorption, residual compressive strength, residual splitting tensile strength and also ultrasonic pulse velocity were determined after air cooling. Microstructures were investigated by scanning electron microscopy. Lightweight concrete with vermiculite shows a good performance at elevated temperatures. Expanded vermiculite is a significant lightweight aggregate for cementitious materials which are used for fire resistance applications. Concrete with vermiculite can be used as cement based refractory

Combined effect of steel fibre and expanded vermiculite on properties of lightweight mortar at elevated temperatures

The goal of this research is to evaluate the influence of steel fibres and expanded vermiculite on some physical and mechanical properties of lightweight mortar at elevated temperatures. An experimental program has been carried out on lightweight mortar specimens exposed to high temperatures up to 1100 degrees C, combining different concentrations of both, steel fibres as a reinforcement of the mortar and expanded vermiculite. The target properties of the mortar to be determined were the flexural strength, the compressive strength and the ultrasonic pulse velocity of hardened mortar after air cooling. Non-linear models derived from a regression analysis and 3D graphics for the measured properties with good agreement to the test results are also presented. Lightweight mortar with expanded vermiculite shows a good performance at elevated temperatures that improves as the percentage of added fibre increases

Site-specific proteasome phosphorylation controls cell proliferation and tumorigenesis

Despite the fundamental importance of proteasomal degradation in cells, little is known about whether and how the 26S proteasome itself is regulated in coordination with various physiological processes. Here we show that the proteasome is dynamically phosphorylated during the cell cycle at Thr 25 of the 19S subunit Rpt3. CRISPR/Cas9-mediated genome editing, RNA interference and biochemical studies demonstrate that blocking Rpt3-Thr25 phosphorylation markedly impairs proteasome activity and impedes cell proliferation. Through a kinome-wide screen, we have identified dual-specificity tyrosine-regulated kinase 2 (DYRK2) as the primary kinase that phosphorylates Rpt3-Thr25, leading to enhanced substrate translocation and degradation. Importantly, loss of the single phosphorylation of Rpt3-Thr25 or knockout of DYRK2 significantly inhibits tumour formation by proteasome-addicted human breast cancer cells in mice. These findings define an important mechanism for proteasome regulation and demonstrate the biological significance of proteasome phosphorylation in regulating cell proliferation and tumorigenesis

Common Childhood Epilepsy Mimics

Unusual movements in children frequently generate concern of underlying seizures from parents and lead to professional review. Stigma associated with epilepsy heightens anxiety and a wish to confirm or exclude the diagnosis as soon as possible. These considerations could lead to a wrong diagnosis of epilepsy being given with unwarranted exposure to medications with potential side effects and cost burden to families. This chapter seeks to provide practitioners in pediatric epilepsy with an exploration of practical differential diagnoses for epilepsy in children, particularly for convulsive seizures. Evaluation of all epilepsy mimics requires a precise and relevant history to help arrive at a diagnosis. Epilepsy mimics across various ages will be reviewed, with the most common differential diagnoses presented first. Examples of common potential epilepsy mimics include benign sleep myoclonus, which is frequently observed in infants and may be a challenge to differentiate from myoclonic seizures in infants. It is a very common phenomenon in pre-term infants with an incidence of 57–132 per 1000 live births. Breath-holding spells among toddlers are common and may be mistaken for epilepsy, as can reflex anoxic seizures. Self-gratification phenomena have been observed from infancy onward and may resemble clonic seizures. Inattention in school-going children is a differential diagnosis for absence seizures and both conditions may co-exist. Stressed or traumatized children may present with non-epileptic psychogenic seizures, as can children with established seizures. Lack of concurrent electrophysiological correlates and absence of stereotypic presentation help differentiate inattention and non-epileptic seizures from childhood epilepsy. Sleep-related activity such as hallucinations, parasomnias, and hypnagogic jerks could also be mistaken for epilepsy in children. Video electroencephalogram (video-EEG) telemetry evaluation is invaluable in such cases. Lack of video-EEG services, simple videos, or EEG studies in resource-poor settings makes diagnosis of epilepsy imitators challenging. The differences between epilepsy and common differential diagnoses for practitioners in resource-limited settings who may lack access to requisite investigative tools will be addressed in the following text. The outcome for most epilepsy mimics is excellent with minimal morbidity and mortality. The potential danger posed by unnecessary medical interventions caused by misdiagnosis of epilepsy makes it imperative that this possibility is minimized