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We investigated strontium oxide (SrO) as an interlayer material to enhance the UV stability of a CH3NH3PbI3 perovskite solar cell. Moisture and over 400 nm wavelength of light were excluded to investigate the effect of UV light only. Two different interlayer fabrication processes were examined to optimize the performance of this solar cell. Devices fabricated by dipping for 30 min in SrO solution exhibited photoconversion efficiencies of 15.5%, whereas those fabricated with 60-min dipping showed photoconversion efficiencies of 15% and exhibited local Sr agglomeration. Devices with SrO displayed lower initial efficiencies than those without any SrO layer (17.6%), However, a device without SrO retained only 34.4% of its initial efficiency after 100 h of UV exposure. In contrast, SrO-incorporated devices retained almost 60.0% of their initial efficiency. Severe μ-PL mapping intensity degradation was observed in devices that did not include the interlayer, but no degradation was observed in those with the SrO interlayer. This can be attributed to the passivation of the degradation sites by SrO.

Recently, the need for rapid, reliable, and low-cost drug susceptibility testing (DST) methods has increased due to the emergence of multidrug-resistant Mycobacterium tuberculosis. Colorimetric methods of DST provide results more quickly than standard culture methods and are inexpensive than molecular methods. Thus, colorimetric methods, such as the nitrate reductase assay (NRA), are being recommended. We searched Medline PubMed for reports on the NRA for DST of M. tuberculosis written in English and published within the last five years. We selected 20 reports on six major anti-TB drugs and conducted a meta-analysis using Meta-Disc software. The pooled sensitivities for isoniazid, rifampicin, streptomycin, ethambutol, ofloxacin, and kanamycin were 95.4%, 96.4%, 91.5%, 93.1%, 99.3%, and 88.4%, and the pooled specificities were 98.5%, 99.2%, 92.9%, 97.8%, 97.4%, and 99.4%, respectively. The area under the summary receiver operator curve for all drugs was 0.9723-0.9952. The time to results (TTR) for the direct and indirect NRAs was 7-28days and 6-15days, respectively. Quality assessments were conducted using the quality of diagnostic accuracy studies tool (QUADAS-2) items, and most reports showed good performance. However, ethambutol, streptomycin, and kanamycin showed relatively low sensitivity. We performed a quantitative NRA in liquid media at various inoculum concentrations. The TTR at 4.94×106, 1.67×104, and 2.27×102CFU/mL was 4, 14, and 14days, respectively. The minimum absorbance and nitrite concentration for positive samples were 0.8 and 168μM, respectively. We propose a quantitative standard to determine sample positivity to address the problems with the current standard NRA which is much less expensive than the conventional assay conducted on solid medium.

In this study, perovskite thin films (PFs) were conformally deposited on 100 cm2 textured silicon substrates using a two-step vacuum process. The PFs were fabricated by converting thin films of a sputtered-PbO precursor using the chemical vapor deposition process. The conversion of PbO thin films into PFs was confirmed by X-ray diffractometry. The uniformity of reflectance and thickness was higher than 86% and 92%, respectively, on 100 cm2 textured substrate. We appliedmethylammoniumvapor treatment for complete conversion without residual layer and the power conversion efficiency was 10.2% on a glass/FTO/TiO2/MAPbI3/Spiro-MeOTAD/Au structure.

Vertical alignment (VA) of a liquid crystal display (LCD) device with a stable pretilt angle has been achieved on ion-bombarded silicon nitride (SiN x) surfaces. The surface energy variation of the SiN x surface with the bonding conversion achieved via ion beam bombardment makes it possible to control the liquid crystal (LC) pretilt angle. X-ray photoelectron spectroscopy revealed that the vertical orientation of the LC molecules occurs on the SiO 2 surface and that this orientation is directionally transformed upon ion bombardment of SiN x thin films. Moreover, the upgraded electro-optical characteristics of VA-LCDs showed potential for high-performance LCD applications on modified SiN x surfaces.

We investigated the electrical properties of polycrystalline silicon (poly-Si) thin film transistors (TFTs) employing field-enhanced solid phase crystallization (FESPC). An n+ amorphous silicon (n+ a-Si) layer was deposited to improve the contact resistance between the active Si and source/drain (S/D) metal instead of ion doping. By using C–V measurement method, we could explain the diffused phosphorous ions (P+ ions) on the channel surface caused a negatively shifted threshold voltage (VTH) of −7.81 V at a drain bias of 0.1 V, and stretched out a subthreshold swing (S) of 1.698 V/dec. This process was almost compatible with the widely used hydrogenated amorphous silicon (a-Si:H) TFT fabrication process and also offers a better uniformity when compared to the conventional laser-crystallized poly-Si TFT process because of non-laser crystallization.

A new method for fabricating large-area well-aligned ZnMgO nanowire arrays, using radio frequency (RF) magnetron co-sputtering, is reported. ZnO nanowire arrays, prepared by metal organic chemical vapor deposition (MOCVD), were used as seed layers for ZnMgO nanowires. For the fabrication of ZnMgO nanowires, RF powers and sputtering pressure were varied to control the supersaturation condition and the kinetic energies of the sputtered materials. Vertically aligned ZnMgO nanowires with [0 0 0 1] preferred orientation were obtained at a working pressure of 20 × 10−3 Torr, RF power of 50 W and 15 W for ZnO and Mg targets, respectively. Crystallinity of the nanostructures were improved with rapid thermal annealing (RTA) at 900 °C. Furthermore, the blue shift in the near-band-edge emission of RTA-treated ZnMgO nanowires was observed during photoluminescence study.

We fabricate a low noise erbium-doped fiber ring laser that can be continuously tuned over 102 nm by insertion of the fiber Fabry–Perot tunable filter (FFP-TF) in the ring cavity with a novel cavity structure and the optimal gain medium length. As an application of this fiber ring laser, we performed the absorption spectroscopy of acetylene (13C2H2) and hydrogen cyanide (H13C14N) and measure the absorption spectra of more than 50 transition lines of these gases with an excellent signal to noise ratio (SNR). The pressure broadening coefficients of four acetylene transition lines are obtained using this fiber ring laser and an external cavity laser diode.

CKII plays a significant role in cell proliferation and cell cycle control. In this report, yeast two-hybrid assay and pull-down assay demonstrate that CKBBP2/CRIF1 associates with the beta subunit of CKII in vitro and in vivo. Recombinant CKBBP2/CRIF1 is phosphorylated in vitro by purified CKII and by CKII inhibitor apigenin-sensitive protein kinase in HEK293 cell extract. Phosphoamino acid analysis and mutational analysis indicate that CKII phosphorylates serine at residue 221 within CKBBP2/CRIF1. Furthermore, serine to alanine mutation at residue 221 abrogates the phosphorylation of CKBBP2/CRIF1 observed in HEK293 cell extract, indicating that CKII is a major kinase that is responsible for phosphorylation of CKBBP2/CRIF1. As compared with the wild-type CKBBP2/CRIF1 or nonphosphorylatable mutant CKBBP2(S221A) (in which the serine-221 is replaced by alanine), overexpression of CKBBP2(S221E) in COS7 cells promotes cell proliferation. Taken together, the present results suggest that CKII may be involved in cell proliferation, at least in part, through the phosphorylation of serine-221 within CKBBP2/CRIF1.

The HIV-1 envelope glycoprotein transmembrane subunit, gp41, mediates the fusion of viral and target cell membranes. The 2 helical regions in the ectodomain of gp41, the N-helix and the C-helix, form a helical bundle complex that has been suggested as a fusion-active conformation. Previously, an enzyme-linked immunosorbent assay (ELISA) method had been established to measure the interaction of 2 helical regions of gp41. In this study, the ELISA method was modified to apply high-throughput screening (HTS) of an organic compound library. A few compounds had been identified to prevent the interaction between 2 helical regions of gp41, and they were further shown to inhibit the gp41-mediated viral infection. In addition, they specifically quenched the fluorescence of tryptophan in the N-helix region, indicating that these compounds bound to the N-helix rather than the C-helix of gp41. These results suggested that this assay method targeting gp41 could be used for HTS of HIV fusion inhibitors. (Journal of Biom...

A novel enzyme drug delivery system, Antibody, Targeted, Triggered, Electrically, Modified, Prodrug, Type, Strategy ("ATTEMPTS"), was developed in our laboratory to attenuate the toxicity associated with drug activity at non-targeted tissues. Tissue plasminogen activator is a prime example of an enzyme drug that exhibits systemic toxicity due to its indiscriminate activation of both targeted (i.e., clot-bound) and non-targeted (i.e., systemic) plasminogen. In brief, tissue plasminogen activator (t-PA) was modified to contain positive surface charges and then rendered inactive upon electrostatic binding with a negatively charged heparin-antifibrin antibody conjugate. After targeting the complex to the clot site, t-PA activity was restored by administration of protamine, a clinical heparin antidote. Cation-modified t-PA (CM-tPA) was obtained by chemical conjugation of t-PA with a poly(Arg)7Cys peptide using the crosslinker N-succinimidyl 3-2-(pyridlydithio)propionate (SPDP). Anti-fibrin IgG was chemically conjugated with heparin via oxidation of the carbohydrate moiety on its Fc region. Both in vitro characterization and in vivo studies using a rat thrombosis model clearly demonstrated that heparin-IgG conjugate induced inhibition of CM-tPA could be effectively reversed upon addition of protamine. Overall, the ATTEMPTS system was proven to induce clot dissolution without causing t-PA associated systemic toxicity due to the degradation of critical plasma factors by systemic plasmin production.

A novel surface modi"cation method has been developed to improve biocompatibility of polymeric biomaterials. This approach involves ozonation and then followed by graft polymerization with acrylates containing PEG, sulfonated PEG or by coupling of PEG derivatives. All the reactions were con"rmed by ATR FT-IR and ESCA. The degree of ozonation measured by the iodide method was dependent on the ozone permeability of the polymers used. Surface hydrophilicity was investigated by measuring the contact angles. Ozonation itself yielded a slight increase in hydrophilicity and a decrease in platelet adhesion, but PEG immobilization showed a signi"cant e!ect on surface hydrophilicity and platelet adhesion to con"rmwell-known PEG 's passivity which minimize the adhesion of blood components on polymer surfaces. Both graft polymerization and coupling were e!ective for PU. In contrast, only grafting gave enough yields for PMMA and silicone. Platelet adhesion results demonstrated that all PEG modi"ed surfaces adsorbed lower platelet adhesion than untreated or ozonated ones. Polymers coupled with sulfonated PEG exhibited the lowest platelet adhesion when compared with control and PEG coupled ones by virtue of the synergistic e!ect of non-adhesive PEG and negatively charged SO groups. This PEG or sulfonated PEG immobilization technology using ozonation is relatively simple for introducing uniformsurface modi "cation and therefore very useful for practical application of blood contacting medical devices. 2001 Elsevier Science Ltd. All rights reserved.

Novel poly(ethylene glycol) (PEG) and sulfonated PEG (PEG-SO(3)) acrylate copolymers have been prepared and characterized to apply as coating and blending materials for biomedical applications. The modified surfaces using acrylate copolymers demonstrated increased hydrophilicity, possibly due to the hypothesized reorientation of PEG/PEG-SO(3) chains into water phase. All copolymer surfaces demonstrated less platelet adhesion than control. In addition, platelet adhesion on copolymer surfaces decreased as the chain length of PEG and sulfonated PEG in copolymers increases. All copolymer surfaces reduced bacterial adhesion significantly and the adhesion level differs depending on surfaces as well as media. The obtained results attest to the usefulness of these copolymers as a coating or additive material to improve the blood compatibility of blood contacting devices.

Human Nopp140 is a highly phosphorylated nucleolus protein and involved in the biogenesis of the nucleolus. It interacts with a variety of proteins related to the synthesis and assembly of the ribosome including a ubiquitous protein kinase CK2 which mediates cell growth and prevents apoptosis. We showed that hNopp140 is a highly intrinsically disordered protein (IDP) lacking stable secondary structures over its entire sequence of 710 residues. In this work, we employed various biophysical approach, for example, Circular Dichroism (CD), Electron Paramagnetic Resonance (EPR) and Forster resonance energy transfer (FRET), to investigate the intrinsic nature of hNopp140 and its structural changes by various conditions, interaction with CK2alpha.