Practical Enhancements in Current Density and Power Generation of Bifacial Semitransparent Ultrathin CIGSe Solar Cells via Utilization of Wide Bandgap Zn-Based Buffer.

Among many building-integrated semitransparent photovoltaics (BISTPVs), semitransparent ultrathin (STUT) Cu(Inx ,Ga1-x )Se2 (CIGSe) solar cells are distinguishable due to their potential high power conversion efficiency (PCE) among other thin-film solar cells, versatile applicability based on thin film deposition processes, high stability consisting of all inorganic compositions, and practical expandability to bifacial applications. However, the fundamental trade-off relationship between PCE and transparency limits the performance of BISTPV because implementing a higher semitransparency lowers the optical budget of incoming light. To expand the available optical budget and to enhance the PCE while maintaining a suitable transparency in STUT CIGSe solar cell with single-stage coevaporated 500-nm-thick absorber, an atomic layer deposited wide bandgap Zn(O,S) buffer is introduced as the replacement of conventional CdS buffer, which partially limits incoming light less than 520 nm in wavelength. As a replacement result, more incoming light becomes valid for power conversion, and the short circuit current density (Jsc ) has increased comparatively by 17%, which has directly lead to a large increase in PCE up to 12.41%. Furthermore, Zn(O,S) buffer in the STUT CIGSe solar cell also has enhanced the bifacial compatible efficiency (BCE), which has increased to 14.44% at 1.3 sun and 19.42% at 2.0 sun.

Near-Infrared to Visible Up-Conversion Luminescence Characteristics of Er, Yb Co-Doped LaVO4 Phosphors.

Er3+ and Yb3+ co-doped LaVO4 phosphors were synthesized by the facile solid state reaction method. Er3+ ions concentrations were changed from 0.01 to 0.2 mol for the fixed Yb3+ ions concentration at 0.15 mol. The crystalline structures of the phosphors were investigated by X-ray diffraction (XRD). The composition of the phosphors were investigated by X-ray photoelectron spectroscopy (XPS) analysis. The photoluminescence emissions based on the blue emission near 466 nm and green emission near 553 nm were observed and the highest emission intensity occurred for the sample LaVO4:Yb0.15, Er0.20. The green and red up-conversion emissions were observed in Er3+, Yb3+ co-doped LaVO4 phosphors under the excitation of 980 nm laser diode. LaVO3:Yb3+, Er3+ phosphors could be utilized to produce green colored LEDs by excitation for infra-red LED.

Up-Conversion Luminescence Properties of LaGaO3:Yb3+, Er3+ Phosphors.

LaGaO3:Er3+, Yb3+ powder with different Er3+ contents (0.01~0.10 mol) was synthesized by a conventional solid-state reaction. The structure, morphology and photoluminescence properties of the as-prepared phosphors were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and fluorescence spectrophotometer techniques, respectively. The photoluminescence (PL) emissions based on the green emission near 522 and 544 nm were observed and the highest emission intensity occurred for the sample LaGaO3:Yb0.15, Er0.07. The green and red up-conversion emissions were observed in Er3+, Yb3+ co-doped LaGaO3 phosphors under the excitation of 980 nm laser diode.

Reactivation of transgene expression by alleviating CpG methylation of the Rous sarcoma virus promoter in transgenic quail cells.

In this study, we investigated the relative expression of the Rous sarcoma virus (RSV) promoter-driven expression of enhanced green fluorescent protein (EGFP) in fibroblasts of transgenic quails. We analyzed the direct influence of CpG methylation of the RSV promoter on the transcriptional activity of delivered transgenes. Embryonic fibroblasts collected from homozygous transgenic quail (TQ2) were treated with 50 µM of DNA methyltransferase inhibitor followed by 5-aza-2'-deoxycytidine (5-azadC) for 48 h, and changes in expression were then analyzed by flow cytometry. The results show a significant increase of EGFP expression in TQ2 embryonic fibroblasts (QEFs) (2.64% to 79.84%). Subsequent methylation-specific amplification revealed that 5-azadC significantly reduced the CpG methylation status in the RSV promoters of the QEFs (86.42 to 48.41%); even after 5-azadC was withdrawn, CpG methylation remained decreased in expanded culture (16.28%). Further analysis showed that potential transcription factor binding sites existed in the CpG methylation site of the RSV promoter. These results may provide the basis for understanding the epigenetic mechanism responsible for transgenic animal production and genetic preservation.

Production of biofunctional recombinant human interleukin 1 receptor antagonist (rhIL1RN) from transgenic quail egg white.

Oviduct-specific expression of heterologous recombinant proteins in transgenic birds is a promising technology for the large-scale production of therapeutic proteins in eggs. We describe the production of recombinant human interleukin 1 receptor antagonist (rhIL1RN) in the eggs of transgenic quails. To drive tissue-specific expression of rhIL1RN, a 1.35-kb fragment of the chicken ovalbumin promoter, which contains both the steroid-dependent regulatory element and the negative regulatory element, was used. A transgenic quail was generated by microinjection of a concentrated stock of lentivirus into stage X blastodermal cells. A single copy of the transgene was integrated into the seventh intron of the gene for conserved oligomeric golgi complex protein 5 (COG5) on chromosome 1. As expected, rhIL1RN expression was restricted to oviductal tissue, and the amount of protein deposited in the eggs of homozygous transgenic quails ranged from 88.7 to 233.8 ng/ml. Transgene expression was conserved from the G(1) generation to the G(4) generation, and there was no evidence of transgene silencing. In a bioassay using the EL4.NOB-1/CTLL-2 coculture system, no significant difference was observed between the egg-produced rhIL1RN and a commercially available rhIL1RN (anakinra).

Generation of transgenic quail through germ cell-mediated germline transmission.

Here, we describe the production of transgenic quail via a germline transmission system using postmigratory gonadal primordial germ cells (gPGCs). gPGCs retrieved from the embryonic gonads of 5-day-old birds were transduced with a lentiviral vector and subsequently transferred into recipient embryos. Testcross and genetic analyses revealed that among three germline chimeric G0 quail, one male produced transgenic offspring; of 310 hatchlings from the transgenic germline chimera, 24 were identified as donor-derived offspring, and 6 were transgenic (6/310, 1.9%). Conventional transgenesis using stage X blastodermal embryos was also conducted, but the efficiency of transgenesis was similar between the two systems (<1.6 vs. 1.9% for the conventional and gPGC-mediated systems, respectively). However, substantial advantages can be gained from gPGC-mediated method in that it enables an induced germline modification, whereas direct retroviral transfer to stage X embryos causes mosaic integration. The use of gonadal PGCs for transgenesis may lead to the production of bioreactors.

MPSS profiling of embryonic gonad and primordial germ cells in chicken.

The massively parallel signature sequencing (MPSS) provides a greater depth of coverage than expressed sequence tag scan or microarray and provides a comprehensive expression profile. We used the MPSS technology to uncover gene expression profiling in the early embryonic gonads and primordial germ cells (PGCs) in the chicken. Total numbers of sequenced signatures were 1,012,533 and 995,676 for the PGCs and gonad, respectively. Using a noise distribution model, we found that 1.67% of all signatures are expressed at a higher level in PCGs and 2.81% of all signatures are expressed at a higher level in the gonad. The MPSS data are presented via an interactive web interface available at http://snugenome.snu.ac.kr/MPSS. The MPSS data have been submitted to the Gene Expression Omnibus of the National Center for Biotechnology Information (accession number GSM137300 and GSM137301 for PGCs and gonad, respectively).

A testis-mediated germline chimera production based on transfer of chicken testicular cells directly into heterologous testes.

In this study, we proposed a testis-mediated germline chimera production system based on the transplantation of testicular cells directly into heterologous testes. The testicular cells of juvenile (4-wk-old) or adult (24-wk-old) Korean Ogol chickens with a recessive pigmentation inhibitory gene, with or without prior culture, were injected (2 x 10(7) cells/head) into the seminiferous tubules of juvenile or adult recipients with White Leghorn with a dominant pigmentation inhibitory gene in a 2 x 2 factorial arrangement. The localization of transplanted cells into the inner space of the seminiferous tubules was confirmed within 24 h after injection. Subsequent testcross analyses showed that 7.8% (5/64) of the recipients had chimeric status in their testes. The periods of time from transfer to hatching of the first progeny with black feathers were 38 and 45 days for adult cells transplanted into an adult recipient, 188 days for adult cells into a juvenile recipient, and 137 days for juvenile cells into a juvenile recipient. Culture of the testicular cells derived both colony-forming and monolayer-forming cells. The colony-forming cells were stained positively for periodic acid Schiff solution, and further reacted with anti-SSEA-1, anti-SSEA-3, and anti-SSEA-4 antibodies both before and after culture for 15 days. In conclusion, it may be possible to develop the testis-mediated germline chimera production technique, which extends the feasibility of genetic manipulations in avian species.

Establishment of an in vitro culture system for chicken preblastodermal cells.

To develop an alternative source for chicken pluripotent cells, we examined (1) whether undifferentiated preblastodermal cells could be subcultured in vitro for an extended period and (2) how subculturing affected the physiological properties of preblastodermal cells. The average number of preblastodermal cells was 2,397 in stage V embryos and 36,345 in stage VII embryos; stage X embryos had an average of 53,857 blastodermal cells. The average cell size decreased significantly (70.63-18.83 microm in diameter; P < 0.0001) as the embryo grew; this was closely related to a reduction in the size and number of lipid vesicles in the cell cytoplasm. The culture conditions were optimized for the stage V preblastodermal cells and the control stage X blastodermal cells. On STO feeder cells, the preblastodermal cells achieved stable growth in vitro only in HES medium or a mixed medium of the Knockout DMEM and HES media. However, more than 10 passages of preblastodermal cells at intervals of 3-4 days was possible only by using the Knockout/HES mixed medium and BRL cell-conditioned HES medium for the primary cultures and subcultures, respectively. Colony-forming preblastodermal cells had well-delineated cytoplasm, which was positively stained for stem cell-specific markers by anti-stage-specific embryo antigen-1 antibody, periodic acid-Schiff's solution, and alkaline phosphatase. When preblastodermal cells with or without culturing were transferred into the blastodermal cavity of stage X embryos, only in vitro-cultured preblastodermal cells at stage V (4/5 = 80%) and stage VII (2/8 = 25%) induced somatic chimerism in recipient chickens. In conclusion, undifferentiated preblastodermal cells could be subcultured, and only the colony-forming preblastodermal cells that stained positively for stem cell markers could induce somatic chimerism.