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Over the past decades, organometallic complexes with precious elements, such as ruthenium and iridium, are widely used as visible-light photoredox catalysts. Recently, more and more complexes based on earth-abundant and inexpensive elements have been used as sensitizers in photochemistry. Although the photoexcited state lifetimes of iron complexes are typically shorter than those of traditional photosensitizers, the utilization of iron catalysts in photochemistry has sprung up owing to their abundance, low price, nontoxicity, and novel properties, including exhibiting ligand to metal charge transfer states. This concept focuses on recent advances in light-driven iron catalysis in organic transformations, including iron/photoredox dual catalysis, light-induced iron photoredox catalysis and light-induced generation of active iron catalysts. The prospect for the future of this field is also discussed.

The first thiocarboxylation of styrenes and acrylates with CO2 was realized by using visible light as a driving force and catalytic iron salts as promoters. A variety of important β-thioacids were obtained in high yields. This multicomponent reaction proceeds in an atom- and redox-economical manner with broad substrate scope under mild reaction conditions. Notably, high regio-, chemo-, and diasteroselectivity are observed. Mechanistic studies indicate that a radical pathway can account for the unusual regioselectivity.

Background MicroRNAs (miRNAs) are short, noncoding RNAs that inhibit the expression of target genes that play roles in tumorigenesis. MiR-21, miR-31, and miR-184 are oncogenic miRNAs for head and neck squamous cell carcinoma (HNSCC). Factor-inhibiting hypoxia (FIH)-inducible factor is known to inactivate hypoxia-induced downstream effectors and is involved in HNSCC suppression. This study investigates whether miR-21, miR-31, and miR-184 target FIH in HNSCC. Methods Reporter assays, Western blot analysis, quantitative reverse transcriptase-polymerase chain reaction (PCR) analysis, and phenotypic assays were used to prove that miR-21, miR-31, and miR-184 directly target FIH. Clinicopathological implications of the gene expression were also analyzed. Results MiR-21, miR-31, and miR-184 directly bind to various sites in the 3′ untranslated region (UTR) of FIH transcript, and this binding is associated with decreased FIH protein expression in HNSCC cells. Treatment with the precursors of these miRNAs increases the proliferation and migration of HNSCC cells. Concomitant treatment with precursors repressed FIH and enhanced oncogenicity most profoundly. Upregulation of miR-21, miR-31, and miR-184 expression is found in more than 80% of HNSCC tumors and 72% of tumors have concordant upregulation of these 3 oncogenic miRNAs. The highest expression of these miRNAs is present in T4b and stage IVB tumors. Downregulation of FIH mRNA expression is noted in 69% of HNSCC tumors, and in tumors exhibiting high expression of these miRNAs, the FIH mRNA expression is consistently downregulated. Conclusion This study provides novel clues indicating that miR-21, miR-31, and miR-184 co-target FIH tumor suppressor during pathogenesis in the vast majority of HNSCC. © 2014 Wiley Periodicals, Inc. Head Neck, 2015

J Oral Pathol Med (2011) 40: 560–566 Backgrounds: MicroRNAs are small noncoding RNAs involved in posttranscriptional gene regulation, which play an important role in both physiological functioning and pathological progression. The miR-221/miR-222 microRNA family has been shown to be related to the neoplastic process in a number of different types of cancers; nevertheless, its function in oral squamous cell carcinoma (OSCC) remained uncertain. Materials and Methods: Paired OSCC and matched noncancerous oral mucosa were examined for miR-221/miR-222 expression using quantitative reverse-transcription PCR. Ectopic expression of miR-221/miR-222 by lentiviral infection was investigated to explore its in vitro and in vivo impact on the oncogenic phenotype and the expression of various target genes. The expression of Cip/Kip cell cycle regulator p27 in tumors was analyzed with immunohistochemistry. Results: The expression levels of miR-221 and miR-222 were highly correlated in OSCC. Increased miR-221/miR-222 expression was found in 40% of OSCC tissues. The ectopic expression of miR-221 or of miR-222 increased growth and anchorage-independent colony formation of OSCC cell lines. It also resulted in an increase in the tumorigenesis of an OSCC cell line in nude mice. Western blot analysis suggested that p27 and p57 might be the targets of miR-221/miR-222. p27 expression was reversely associated with the miR-221 and miR-222 expression level in OSCC tissues. Conclusions: Our findings suggested that increased miR-221/miR-222 expression was associated with the OSCC cell growth.

New fully integrated single-chip impulse ultra-wideband (UWB) transmitter front-ends, integrating tunable impulse or monocycle pulse generator with bi-phase shift keying (BPSK) modulator, has been developed using a standard low-cost 0.18-μm CMOS process. The monocycle pulse generator component produces 0.7–0.75 V peak-to-peak monocycle pulse with 140–350 ps tunable pulse duration. The impulse generator generates 0.95–1.05 V peak-to-peak Gaussian-type impulse signal with 100–300 ps tunable pulse duration. The BPSK modulator controls the pulse generator to generate positive or negative pulse signal depending on the “1” or “0” digital data information. The pulse signals produced by the developed transmitters are useful for various UWB applications, especially those requiring the capability of changing ranges and resolutions using only a single system. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1609–1614, 2010; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/mop.25250

Oral Diseases (2010) 16, 360–364 Backgrounds: Oral squamous cell carcinoma (OSCC) is a worldwide disease. MicroRNAs are endogenously expressed non-coding RNAs that have important biological and pathological functions. miR-31 was found markedly up-regulated in OSCC and several other malignancies. However, miR-31 expression was also down-regulated in the metastasis process of breast carcinoma. Materials and methods: Using quantitative RT-PCR analysis, we identified plasma miR-31 in OSCC patients (n = 43) and case controlled individuals (n = 21). Nine OSCC patients saliva were also analyzed. The Mann–Whitney test and Wilcoxon matched pairs test were used to compare the differences among the various clinical variants. Results: miR-31 in plasma was significantly elevated in OSCC patients relative to age and sex-matched control individuals. This marker yielded a receiver operating characteristic curve area of 0.82 and an accuracy of 0.72 defined by leave-one-out cross-validation. In addition, the plasma miR-31 in patients was remarkably reduced after tumor resection suggesting that this marker is tumor associated. Our preliminary analysis also demonstrated the feasibility of detecting the increase of miR-31 in patient’s saliva. Conclusion: This study concluded that plasma miR-31 could be validated a marker of OSCC for diagnostic uses.

A single-chip broadband CMOS receiver front-end, integrating a low-noise amplifier (LNA), a correlator, and a template pulse generator, was investigated in nonsinusoidal time-domain environment for possible use as an impulse-type ultra-wideband (UWB) receiver front-end. Particularly, the CMOS LNA and the multiplier making up the core component of the correlator were designed, fabricated, and tested to verify operation in the UWB range. Time-domain results of the integrated CMOS receiver front-end demonstrate its workability as a receiver for nonsinusoidal UWB applications. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2590–2595, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24682

A new compact, low-cost uniplanar impulse generator using coplanar waveguide structure has been designed, built, and tested. This uniplanar circuit consists of three functions: initial impulse generation, impulse amplification, and impulse compression, which are realized by a step-recovery diode and two-stage GaAs MESFET circuits, respectively. The impulse response has an amplitude of 2.3 V and a half-power pulse width of 115 pS. It has larger amplitude and narrower pulse width than the impulse generated by the SRD circuit alone. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 470–472, 2003