Universal selective transfer printing via micro-vacuum force.

Transfer printing of inorganic thin-film semiconductors has attracted considerable attention to realize high-performance soft electronics on unusual substrates. However, conventional transfer technologies including elastomeric transfer printing, laser-assisted transfer, and electrostatic transfer still have challenging issues such as stamp reusability, additional adhesives, and device damage. Here, a micro-vacuum assisted selective transfer is reported to assemble micro-sized inorganic semiconductors onto unconventional substrates. 20 µm-sized micro-hole arrays are formed via laser-induced etching technology on a glass substrate. The vacuum controllable module, consisting of a laser-drilled glass and hard-polydimethylsiloxane micro-channels, enables selective modulation of micro-vacuum suction force on microchip arrays. Ultrahigh adhesion switchability of 3.364 × 106, accomplished by pressure control during the micro-vacuum transfer procedure, facilitates the pick-up and release of thin-film semiconductors without additional adhesives and chip damage. Heterogeneous integration of III-V materials and silicon is demonstrated by assembling microchips with diverse shapes and sizes from different mother wafers on the same plane. Multiple selective transfers are implemented by independent pressure control of two separate vacuum channels with a high transfer yield of 98.06%. Finally, flexible micro light-emitting diodes and transistors with uniform electrical/optical properties are fabricated via micro-vacuum assisted selective transfer.

Caffeine-induced hypokalemia: a case report.

BACKGROUND: With an increase in the global popularity of coffee, caffeine is one of the most consumed ingredients of modern times. However, the consumption of massive amounts of caffeine can lead to severe hypokalemia. CASE PRESENTATION: A 29-year-old man without a specific past medical history was admitted to our hospital with recurrent episodes of sudden and severe lower-extremity weakness. Laboratory tests revealed low serum potassium concentration (2.6-2.9 mmol/L) and low urine osmolality (100-130 mOsm/kgH2O) in three such prior episodes. Urinary potassium/urinary creatinine ratio was 12 and 16 mmol/gCr, respectively. The patient was not under medication with laxatives, diuretics, or herbal remedies. Through an in-depth interview, we found that the patient consumed large amounts of caffeine-containing beverages daily, which included > 15 cups of coffee, soda, and various kinds of tea. After the cessation of coffee intake and concomitant intravenous potassium replacement, the symptoms rapidly resolved, and the serum potassium level normalized. CONCLUSIONS: An increased intracellular shift of potassium and increased loss of potassium in urine due to the diuretic action have been suggested to be the causes of caffeine-induced hypokalemia. In cases of recurring hypokalemia of unknown cause, high caffeine intake should be considered.

Protein polyglutamylation catalyzed by the bacterial calmodulin-dependent pseudokinase SidJ.

Pseudokinases are considered to be the inactive counterparts of conventional protein kinases and comprise approximately 10% of the human and mouse kinomes. Here, we report the crystal structure of the Legionella pneumophila effector protein, SidJ, in complex with the eukaryotic Ca2+-binding regulator, calmodulin (CaM). The structure reveals that SidJ contains a protein kinase-like fold domain, which retains a majority of the characteristic kinase catalytic motifs. However, SidJ fails to demonstrate kinase activity. Instead, mass spectrometry and in vitro biochemical analyses demonstrate that SidJ modifies another Legionella effector SdeA, an unconventional phosphoribosyl ubiquitin ligase, by adding glutamate molecules to a specific residue of SdeA in a CaM-dependent manner. Furthermore, we show that SidJ-mediated polyglutamylation suppresses the ADP-ribosylation activity. Our work further implies that some pseudokinases may possess ATP-dependent activities other than conventional phosphorylation.

Trichogenic Photostimulation Using Monolithic Flexible Vertical AlGaInP Light-Emitting Diodes.

Alopecia is considered an aesthetic, psychological, and social issue among modern people. Although laser-induced skin stimulation is utilized for depilation treatment, such treatment has significant drawbacks of high energy consumption, huge equipment size, and limited usage in daily life. Here, we present a wearable photostimulator for hair-growth applications using high-performance flexible red vertical light-emitting diodes (f-VLEDs). Flexible microscale LEDs were effectively fabricated by a simple monolithic fabrication process, resulting in high light output (∼30 mW mm-2), low forward voltage (∼2.8 V), and excellent flexibility for wearable biostimulation. Finally, trichogenic stimulation of a hairless mouse was achieved using high-performance red f-VLEDs with high thermal stability, device uniformity, and mechanical durability.

Inverse regulation of Fe- and Ni-containing SOD genes by a Fur family regulator Nur through small RNA processed from 3'UTR of the sodF mRNA.

Superoxide dismutases (SODs) are widely distributed enzymes that convert superoxides to hydrogen peroxide and molecular oxygen, using various metals as cofactors. Many actinobacteria contain genes for both Ni-containing (sodN) and Fe-containing (sodF) SODs. In Streptomyces coelicolor, expression of the sodF and sodN genes is inversely regulated by nickel-specific Nur, a Fur-family regulator. With sufficient nickel, Nur directly represses sodF transcription, while inducing sodN indirectly. Bioinformatic search revealed that a conserved 19-nt stretch upstream of sodN matches perfectly with the sodF downstream sequence. We found that the sodF gene produced a stable small-sized RNA species (s-SodF) of ∼ 90 nt that harbors the anti-sodN sequence complementary to sodN mRNA from the 5'-end up to the ribosome binding site. Absence of nearby promoters and sensitivity to 5'-phosphate-specific exonuclease indicated that the s-SodF RNA is a likely processed product of sodF mRNA. The s-SodF RNA caused a significant decrease in the half-life of the sodN mRNA. Therefore, Nur activates sodN expression through inhibiting the synthesis of sodF mRNA, from which inhibitory s-SodF RNA is generated. This reveals a novel mechanism by which antagonistic regulation of one gene is achieved by small RNA processed from the 3'UTR of another gene's mRNA.

Anti-proliferative effect of Klimaktoplan® on human breast cancer cells.

OBJECTIVE: With the health concerns of menopausal hormone replacement therapy, alternatives have been sought. Klimaktoplan® is a homeopathic formulation consisting of four main components and has been used for relief of menopausal symptoms for a long time. The study investigated the safety of Klimaktoplan® through its effect on the proliferation of breast cancer (MCF-7) and non-malignant mammary epithelial cells (MCF-10A). METHODS: MCF-7 and MCF-10A cells were cultured in 312.5, 625, and 1,250 µg/ml Klimaktoplan®. 17-Beta estradiol (E2) and medroxyprogesterone 17-acetate (MPA) were used for comparison with Klimaktoplan®. E2 only (0.001, 0.01, and 0.1 µM), and the combination of E2 (0.001, 0.01, and 0.1 µM) and MPA (0.01, 0.1, and 1 µM) were tested. Control cells for Klimaktoplan® and E2 groups were treated with dimethylsulfoxide (DMSO), and DMSO + ethanol was used for the combination group. Cellular proliferation was evaluated by the formation of insoluble formazan after incubation of 4 days. RESULTS: Klimaktoplan® had a concentration-dependent anti-proliferative effect on breast cancer cells at 625 and 1,250 µg/ml, while not affecting proliferation of non-malignant mammary cells at any tested concentration. The effect of lactose was evaluated as lactose (the adjuvant of Klimaktoplan®) affect cell growth. E2 and lactose increased the proliferation of both malignant and non-malignant cells. The effect of E2 + MPA on the proliferation of malignant and non-malignant mammary cells was lower than estradiol only, but was higher than control. CONCLUSIONS: Klimaktoplan® has an anti-proliferative effect on breast cancer cells, but not for non-malignant mammary epithelial cells, unlike E2 and E2 + P. With further research, KP would be a good alternative or additive in women with menopausal symptoms who wish to avoid conventional E or E + P hormone therapy.