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Nontoxic metal-halide perovskite materials have triggered a revolution of emitting devices as well as solar cells. In this work, we demonstrate a lead-free γ-CsSnI3 perovskite random lasing operate...

The CsPbBr3 microwires with unique isosceles right triangle cross-sections are commonly observed via chemical vapor deposition method. In this work, we study the correlations between measured multi-mode lasing behaviors and the simulation of the mode patterns inside the triangular-rod microcavity. We confirm that lasing action with higher-order transverse modes can well sustain, even when these modes experience large optical loss due to the isosceles triangle cross-section. By comparing the experimental and simulation results, the higher-order transverse modes tend to show up prior to the fundamental transverse modes for wider microwires. We attribute this behavior to the nonuniform field distribution caused by the high absorption efficiency of CsPbBr3. We also elaborate on the difficulties to sustain the whispering gallery mode in the CsPbBr3 triangular-rod microcavity, which implies that the lateral dimension and geometry of the cavity should be considered carefully for the future design of low threshold wire-based laser devices.

The thermal deposition of lead iodide (PbI2) results in the changes in the contact surface of a poly (3,4-ethylenedioxythiophene) poly (styrene sulfonate) (PEDOT:PSS) layer of solar cells (SCs). The changed contact surface of PEDOT:PSS layer after the thermal deposition of PbI2 remains stable after PbI2 is converted into perovskite and leaves the degraded perovskite/PEDOT:PSS interface. The degraded perovskite/pristine PEDOT:PSS interface leads to a low power conversion efficiency (η%) of SCs at 3.84%. The properties of the contact surface of the PEDOT:PSS layer during the thermal deposition of PbI2 can be retained by treating PEDOT:PSS with dimethyl sulfoxide (DMSO) and maintain the perovskite/PEDOT:PSS interface in good condition after PbI2 is converted. Perovskite SCs with DMSO-treated PEDOT:PSS substantially improves η% from 3.84% to 9.58%.

In this research, we demonstrate regular-type perovskite solar cells based on tungsten trioxide nanoparticles layer (WO3 NL) as the electron transport layer and methylammonium lead iodide nanowires (MAPbI3 NWs) as the absorbing layer. By adjusting the amount of the anti-solvent DMF, MAPbI3 NWs with different diameters ranging from 50 to 100 nm and lengths extending to several micrometers were obtained. [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) and cesium carbonate (Cs2CO3) were introduced between WO3 NL and MAPbI3 NWs to improve film morphology and charge transfer ability. Meanwhile, spiro-MeOTAD doped with bis(trifluoromethane)sulfonimide lithium salt (Li-TFSI) was utilized to enhance hole transport. Finally, the perovskite solar cells with the configuration of ITO/WO3 NL/Cs2CO3/PCBM/MAPbI3 NWs/spiro-MeOTAD/Au were fabricated and evaluated. To date, perovskite NWs treating with the proper amount of the anti-solvent DMF possess higher absorption, faster carrier transportation and lower recombination that are responsible for photovoltaic application.

Large-grained and well-oriented methylammonium lead tribromide (MAPbBr3) perovskite was formed from the conversion of amorphous lead bromide (PbBr2) doped with phenethylamine (PEA). The addition of PEA ions (with an optimized molar ratio of 0.008%) to the PbBr2 solution assisted the formation of a smooth PEA-doped PbBr2 layer by spin-coating. Then, the PEA-doped PbBr2 thin film would convert into large-grained and well-oriented MAPbBr3 with the help of a solid-vapor reaction under a vaporized methylammonium bromide (MABr) and choline chloride (CC) atmosphere. Furthermore, both PEA and CC would passivate the defects of perovskite to improve the crystal quality of perovskite. By applying this perovskite layer in perovskite light-emitting diodes (PeLEDs), the maximum luminance and current efficiency of PeLEDs could reach 20,869 cd/m2 and 3.99 cd/A, respectively; these values are approximately five and three times larger than those of PeLEDs without PEA. The perovskite converted from spin-coated PbBr2 with a PEA dopant remarkably improved the luminance and current efficiency of its PeLEDs.

Colorectal cancer (CRC) is a major health problem due to its high mortality rate. The incidence of CRC is increasing in young individuals. Oxaliplatin (OXA) is an approved third-generation drug and is used for first-line chemotherapy in CRC. Although current standard chemotherapy improves the overall survival of CRC patients, an increasing number of reports of OXA resistance in CRC therapy indicates that resistance has become an urgent problem in clinical applications. Dicer is a critical enzyme involved in miRNA maturation. The expression of Dicer has been reported to be involved in the resistance to various drugs in cancer. In the present study, we aimed to investigate the role of Dicer in OXA resistance in CRC. We found that OXA treatment inhibited Dicer expression through decreasing the protein stability. OXA-induced Dicer protein degradation occurred through both proteasomal and lysosomal proteolysis, while the CHIP E3 ligase was involved in OXA-mediated Dicer ubiquitination and degradation. We established stable OXA-resistant clones from CRC cells, and observed that the CHIP E3 ligase was decreased, along with the increased Dicer expression in OXA-resistant cells. Knockdown of Dicer resensitized CRC cells to OXA treatment. In this study, we have revealed the role of miRNA biogenesis factors in OXA resistance in CRC cells.

WD repeat and HMG-box DNA binding protein 1 (Wdhd1) is the mouse ortholog of budding yeast Chromosome Transmission Fidelity 4 (CTF4), the protein product of which integrates the MCM2-7 helicase and DNA polymerase α/primase complex to initiate DNA replication. Previous work in fruit flies, Xenopus egg extracts, and human cell lines suggest that Wdhd1 is required for efficient DNA synthesis. However, rigorous in vivo functional studies on Wdhd1 in mammals are unavailable. In the present study, we have successfully generated a Wdhd1 null allele in mice through CRISPR/Cas9-mediated genome editing to investigate the role of Wdhd1 in embryogenesis in vivo. We characterized Wdhd1 expression using quantitative reverse-transcription polymerase chain reaction, and assessed embryonic cell proliferation by histology in both pre- and peri-implantation embryos. While Wdhd1 heterozygous mutant mice were grossly normal and fertile, we observed a reduction in cell proliferation by the gastrulation stage in Wdhd1 homozygous null mutant embryos which severely hampered their growth and viability. These results indicate that Wdhd1 plays a major role in cell proliferation during embryogenesis in mice.

Single-crystal all-inorganic CsPbBr3 perovskite microplatelets were fabricated to realize lasing at room temperature. Upon optical excitation, whispering-gallery-mode (WGM) lasing was achieved at RT with low threshold (~2.8 μW) and high quality factor (~3000).

The electro-optical performance of nematic liquid crystals (NLCs) dispersed with gold nanoparticles (GNPs) was investigated in this study. The addition of a small amount of GNP dopant decreased the threshold voltage for LC reorientation due to the decreased elastic constant and increased dielectric anisotropy of the LC mixture. The response time of the LC cell was decreased with the addition of tiny amounts of GNPs because of decrease in rotational viscosity of LCs. The doped GNPs also shorten LC reorientation angle during voltage switching, further decreasing the response time of the LC cell. The addition of high amounts of GNPs slowed down the response time of the LC cell, because excess GNPs aggregated and formed networks in the cell, thus disturbing LC alignment and hindering LC reorientation. The measured dielectric spectra of the GNP-LC mixture revealed that the addition of GNPs decreased the relaxation time constant of the LCs. This result confirmed that the GNP dopant decreased the rotational viscosity and elastic constant of the LCs.

Chemotherapy has a good success rate in the treatment of colorectal cancer; however, recurrence of colorectal cancer is still frequent due to acquired resistance. Aurora-A, a cell cycle-regulated kinase, plays an important role in colorectal cancer development and drug resistance. Dicer, one of the key enzymes of the microRNA (miRNA) biogenesis pathway, may be involved in chemoresistance through regulating the expression of miRNAs. According to the TCGA database, the expression levels of Dicer and Aurora-A were increased in colorectal cancer, which may contribute to chemoresistance. Our results showed that the protein levels of Dicer and Aurora-A are increased in oxaliplatin resistant cell lines. Knocked-down expression of Dicer or Aurora-A can enhance drug sensitivity in oxaliplatin-resistant cells; in contrast, overexpression of Dicer or Aurora-A increased drug resistance in parental drug sensitive cells. By next-generation sequencing, we found that the expression of a set of miRNAs is increased in oxaliplatin resistant cells. Dicer overexpression enhances the expression of those miRNAs in drug sensitive parental cells. Clinical evaluation further confirmed the increased expression of those miRNA in the plasma of CRC patients with a poor response to oxaliplatin. Our results suggest that those miRNAs may act as biomarkers to predict oxaliplatin response in colorectal cancer by detecting their plasma miRNAs. The molecular mechanism of those miRNAs in regulating the drug response is currently under our investigation. Citation Format: Li Jyuan Lin, Liang-Yi Hung. Dicer overexpression contributes to chemoresistance in colorectal cancer via up-regulating a set of miRNAs [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3016.

Chemotherapy has a good success rate in colorectal cancer; however, recurrence of colorectal cancer is still frequent due to the development of drug resistance. MicroRNA (miRNA) is a type of non-coding RNA with a size of around 19-22 nucleotides and plays an important role in regulating many biological functions, the onset of diseases, as well as drug response. It was reported that Dicer, one of the key enzymes of the miRNA biogenesis pathway, may be involved in the chemoresistance through regulating the expression of miRNAs. Aurora-A, a cell cycle-regulated kinase, plays a vital role in cancer development and chemoresistance. According to the TCGA database, the expression levels of Dicer and Aurora-A are both increased in colorectal cancer. Here, we demonstrated that overexpressed Aurora-A can regulate the chemodrug response by influencing the miRNA biogenesis pathway via Dicer in colorectal cancer. Our results showed that the protein level, but not the mRNA expression, of Dicer was decreased upon 5-FU or oxaliplatin treatment in drug sensitive cells; whereas, the expression level of Dicer was increased in oxaliplatin resistant cell lines. Knockdown expression of Dicer in oxaliplatin resistant cell lines could reverse the resistance of oxaliplatin. The expression levels of several potential miRNAs changed upon chemodrugs treatment. Interestingly, we found that overexpressed Aurora-A could increase the expression of Dicer and potentiate drug resistance in colorectal cancer cells. In contrast, knockdown expression of Aurora-A decreased Dicer protein expression and led to enhanced drug sensitivity. Taken together, our results suggested that Aurora-A and Dicer can collaborate to regulate drug response through influencing the miRNA biogenesis pathway in colorectal cancer. The further mechanism of Dicer and Aurora-A in chemoresistance is currently under our investigation. Citation Format: Li Jyuan Lin. Aurora-A potentiates chemoresistance via regulating the microRNA biogenesis pathway [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5890.