RESUMO
We report the first demonstration of inkjet-printed 4-terminal microelectromechanical (MEM) relays and inverters with hyper-abrupt switching that exhibit excellent electrical and mechanical characteristics. This first implementation of a printed 4-terminal device is critically important, since it allows for the realization of full complementary logic functions. The floated fourth terminal (body electrode), which allows the gate switching voltage to be adjusted, is bonded to movable channel beams via a printed epoxy layer in a planar structure, which can move downward together via the electrostatic force between the gate electrodes and body such that the channel can also actuate downward and touch the drain electrode. Because the body, channel, and drain electrodes are completely electrically separated, no detectable leakage or electrical interference between the electrodes is observed. The printed MEM relay exhibited an on-state resistance of only 3.48 Ω, immeasurable off-state leakage, subthreshold swing <1 mV/dec, and a stable operation over 10(4) cycles with a switching delay of 47 µs, and the relay inverter exhibits abrupt transitions between on/off states. The operation of the printed 4-terminal MEM relay was also verified against the results of a 3-dimensional (3D) finite element simulation.
RESUMO
Chemical inhibitors of histone deacetylase (HDAC) activity are used as experimental tools to induce histone hyperacetylation and deregulate gene transcription, but it is not known whether the inhibition of HDACs plays any part in the normal physiological regulation of transcription. Using both in vitro and in vivo assays, we show that lactate, which accumulates when glycolysis exceeds the cell's aerobic metabolic capacity, is an endogenous HDAC inhibitor, deregulating transcription in an HDAC-dependent manner. Lactate is a relatively weak inhibitor (IC(50) 40 mM) compared to the established inhibitors trichostatin A and butyrate, but the genes deregulated overlap significantly with those affected by low concentrations of the more potent inhibitors. HDAC inhibition causes significant up and downregulation of genes, but genes that are associated with HDAC proteins are more likely to be upregulated and less likely to be downregulated than would be expected. Our results suggest that the primary effect of HDAC inhibition by endogenous short-chain fatty acids like lactate is to promote gene expression at genes associated with HDAC proteins. Therefore, we propose that lactate may be an important transcriptional regulator, linking the metabolic state of the cell to gene transcription.
Assuntos
Regulação da Expressão Gênica , Inibidores de Histona Desacetilases/farmacologia , Ácido Láctico/farmacologia , Acetilação , Ânions , Butiratos/farmacologia , Linhagem Celular , Meios de Cultura/química , Regulação da Expressão Gênica/efeitos dos fármacos , Histonas/metabolismo , Humanos , Ácido Láctico/análiseRESUMO
Aurora rings are prominent endoscopic features of the inverted colonic diverticulum (ICD), and their appearance alongside a colonic lipoma is an unprecedented phenomenon. The present study reports a case of colonic lipoma with Aurora rings, contradicting the assumption that Aurora rings are indicative of ICD. A 52-year-old male patient presented with left-sided abdominal pain for >1 year, associated with constipation in the form of the decreased frequency of bowel motions every 4 to 5 days. A physical examination revealed an obese, protuberant abdomen and a mildly tender left iliac fossa region without other notable findings. A transabdominal ultrasonography revealed a thickening of the large bowel wall (<7 mm) with a suspected inflammatory lesion on the left side of the colon. During an ileocolonoscopy, multiple diffuse diverticula of various sizes were observed, affecting the entire colonic mucosa. Furthermore, a large (1.5 cm) pedunculated polyp with a thick stalk was found in the sigmoid colon, exhibiting positive Aurora rings. A polypectomy was conducted with the deployment of two hemoclips at the polyp base to prevent perforation. The histopathological examination of the specimen, a 1.3 cm polyp, revealed the presence of a colonic lipoma, rather than an ICD. The identification of Aurora rings has emerged as a significant endoscopic feature in the diagnosis of ICD; nevertheless, the underlying etiology of these rings remains elusive. Based on an extensive search of the literature, no study was found mentioning the appearance of Aurora rings in an endoscopic screening of other colonic conditions other than ICD. The appearance of Aurora rings alongside a colonic lipoma has not previously been mentioned, at least to the best of our knowledge, which renders the differentiation of ICD from lipomas and polyps more challenging.
RESUMO
Gravure printing is an attractive technique for patterning high-resolution features (<5 µm) at high speeds (>1 m/s), but its electronic applications have largely been limited to depositing nanoparticle inks and polymer solutions on plastic. Here, we extend the scope of gravure to a new class of materials and on to new substrates by developing viscous sol-gel precursors for printing fine lines and films of leading transparent conducting oxides (TCOs) on flexible glass. We explore two strategies for controlling sol-gel rheology: tuning the precursor concentration and tuning the content of viscous stabilizing agents. The sol-gel chemistries studied yield printable inks with viscosities of 20-160 cP. The morphology of printed lines of antimony-doped tin oxide (ATO) and tin-doped indium oxide (ITO) is studied as a function of ink formulation for lines as narrow as 35 µm, showing that concentrated inks form thicker lines with smoother edge morphologies. The electrical and optical properties of printed TCOs are characterized as a function of ink formulation and printed film thickness. XRD studies were also performed to understand the dependence of electrical performance on ink composition. Printed ITO lines and films achieve sheet resistance (Rs) as low as 200 and 100 Ω/â¡, respectively (ρ≈2×10(-3) Ω-cm) for single layers. Similarly, ATO lines and films have Rs as low as 700 and 400 Ω/â¡ with ρ≈7×10(-3) Ω-cm. High visible range transparency is observed for ITO (86-88%) and ATO (86-89%). Finally, the influence of moderate bending stress on ATO films is investigated, showing the potential for this work to scale to roll-to-roll (R2R) systems.
RESUMO
The impressive 18th Century Ardgour House again played host to the seventh annual Exploratory Measurement Science Group Symposium. The Symposium was organised as a study retreat for young and established scientists who share a common interest in the development and application of advanced analytical instrumentation. Speakers from a wide range of backgrounds in academia, industry and government were invited to present and discuss their research interests surrounded by the stunning Highland scenery of Fort William.