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Severe acute respiratory syndrome-associated coronavirus 2 is a major global health issue and is driving the need for new therapeutics. The surface spike protein, which plays a central role in virus infection, is currently the target for vaccines and neutralizing treatments. The emergence of novel variants with multiple mutations in the spike protein may reduce the effectiveness of neutralizing antibodies by altering the binding activity of the protein with angiotensin-converting enzyme 2 (ACE2). To understand the impact of spike protein mutations on the binding interactions required for virus infection and the effectiveness of neutralizing monoclonal antibody (mAb) therapies, the binding activities of the original spike protein receptor binding domain (RBD) sequence and the reported spike protein variants were investigated using surface plasmon resonance (SPR). In addition, the interactions of the ACE2 receptor, an anti-spike monoclonal antibody (mAb1), a neutralizing monoclonal antibody (mAb2), the original spike RBD sequence, and mutants D614G, N501Y, N439K, Y453F, and E484K were assessed. Compared to the original RBD, the Y453F and N501Y mutants displayed a significant increase in ACE2 binding affinity, whereas D614G had a substantial reduction in binding affinity. All mAb-RBD mutant proteins displayed a reduction in binding affinities relative to the original RBD, except for the E484K-mAb1 interaction. The potential neutralizing capability of mAb1 and mAb2 was investigated. Accordingly, mAb1 failed to inhibit the ACE2-RBD interaction and mAb2 inhibited the ACE2-RBD interactions for all RBD mutants, except mutant E484K, which only displayed partial blocking., Graphical abstract Image 1

A series of layered double hydroxides (MgxAl-LDHs) catalysts is successfully prepared and effectively transesterificated triglycerides to produce biodiesel and glycerol carbonate, respectively. MgxAl-LDHs catalysts are synthesized by changing the Mg/Al ratio of the LDH hosts and fully characterized by several techniques, including XRD, N2 adsorption, SEM. The effects of ratios of Mg/Al catalyst, reaction temperature, catalyst dosage are thoroughly investigated to determine the optimal reaction conditions. A yield of biodiesel and glycerol carbonate could reach up to 87.5% and 93.4%, respectively, over Mg5Al-LDHs catalyst under batch condition. The transesterification glycerol for glycerol carbonate is successfully carried out in a stirring packed-bed reactor with MgxAl-LDHs coating on the spherical α-Al2O3 catalysts. Additionally, extra-particle mass transfer and intra-particle diffusion do not control the reaction rate. The yield of glycerol carbonate could reach up to 80.2% over Mg5Al-LDHs/α-Al2O3 catalyst.

In this study, a series of 2,2′ and 3,3′ substituted thienoisoindigo (TII)-based small molecules (H3–H7) were synthesized by using 1,3-di(9H-carbazol-9-yl) benzene, N-phenylcarbazole, triphenylamin...

Longans, which are produced in tropical countries, are rich in nutrients and high in commercial value. To extend their shelf life, fresh longans are roasted to dry them out. For the convenience of cooking applications, the dried longan pulp is peeled and seeded beforehand. Presently, this is done manually, thus, this research aims to automate this process. A cutting tool with a serrated bending angle is used to cut the dried longan pulp, and then the longan is fixed by a lifting mechanism. The pulp is breached with a cutting tool and this breach is pushed up against a 6 mm hole in the silicone soft plate of the lifting mechanism to separate out the seed by squeezing. Commercially available dried longans are used in this experiment. The cutting surface width of the cutter designed in this study is 20 mm, and the serration bending angle is 30&deg, This cutter operates at a speed of 29 cm/s on dried longan pulp, attaining a success rate of 85%. The lifting mechanism also presented in this study fixes the dried longan and uses a squeezing motion to separate the flesh from the seed with a silicone soft plate. Here, a lifting speed of 28 mm/s achieves the highest rate of success at peeling, and the success rate of pulp-and-seed separation can reach 86.7%.

In this manuscript, a series of amine tagged short cyclic molecules (cyclopropylamine, cyclobutylamine, cyclopentylamine and cyclohexylamine) were thermally grafted onto p-type silicon (111) hydride surfaces via nucleophilic addition. The chemistries of these grafting were verified via XPS, AFM and sessile droplet measurements. Confocal microscopy and cell viability assay was performed on these surfaces incubated for 24 hours with triple negative breast cancer cells (MDA-MB 231), gastric adenocarcinoma cells (AGS) endometrial adenocarcinoma (Hec1A). All cell types had shown a significant reduction when incubated on these ring-strain cyclic monolayer surfaces than compared to standard controls. The expression level of focal adhesion proteins (vinculin, paxilin, talin and zyxin) were subsequently quantified for all three cell types via qPCR analysis. Cells incubate on these surface grafting were observed to have reduced levels of adhesion protein expression than compared to positive controls (collagen coating and APTES). A potential application of these anti-adhesive surfaces is the maintenance of the chondrocyte phenotype during in-vitro cell expansion. Articular chondrocytes cultured for 6 days on ring strained cyclopropane-modified surfaces was able to proliferate but had maintained a spheroid/aggregated phenotype with higher COL2A1 and ACAN gene expression. Herein, these findings had help promote grafting of cyclic monolayers as an viable alternative for producing antifouling surfaces.

Pyridine-2-carboxylate (pic) has been employed extensively as a blue-shifting ancillary ligand in the production of cyclometalated iridium complexes used in OLEDs, but surprisingly, further elaboration of this ligand has largely been unexplored. In this work we demonstrate a simple and versatile route for modifying picolinate ligands coordinated to iridium. Reacting a μ-chloro iridium(C∧N) dimer (where C∧N is a phenylpyridine-based ligand) with 4-bromopicolinic acid (HpicBr) yields the corresponding iridium(C∧N)2(picBr) complexes, which were readily modified by a Suzuki–Miyaura reaction to give the corresponding aryl-substituted picolinate complexes. The luminescent behavior of these complexes shows that by restricting the torsional angle between the substituent and pic the emission can be shifted by up to 77 nm.

A series of thienoisoindigo (TII)-based dyes (TII 1–4) using different electron-donating moieties (D) and π-linkers were synthesized. The experimental results show that the maximum absorption band of TII 1–4 was located at 611–749 nm. Moreover, their absorption onset was extended to 741–901 nm that covers the near infrared (NIR) region. The bulk-heterojunction solar cell device fabricated by using TII 3/PC61BM as the active layer exhibited a power conversion efficiency (PCE) of 0.82%, showing the potential of TII-based dyes for NIR organic photovoltaics (OPVs). In order to study the structural effect of dyes on the PCE of solar cells, we further designed four TII-based dyes (TII 5–8) and the photophysical and photovoltaic properties for TII 1–8 were investigated through theoretical calculations. Calculated results demonstrate that carbazole group, whose has strong electron-donating ability than D moieties in this study, leads to generate long lifetime of the first excited state and whose generate large short-circuit current (Jsc). Thiophene group, whose has weak resonance energy than other π-linkers, can improve the π delocalization effect throughout whole molecule and generate large open-circuit voltage (Voc). According to these results, TII 3 and TII 8 with the carbazole as D moiety and thiophene as π-linker should be useful in development of a new SM-OPV device.

Osteopontin (OPN) is a multi-functional phospho-glycoprotein that can stimulate angiogenesis through acting on endothelial cells. As angiogenic sprouting involves endothelial-to-mesenchymal transition (EndoMT), we are intrigued to know whether OPN exerts an effect on EndoMT. Clinically, we indeed detected EndoMT-derived cells next to OPN-expressing cells in colorectal cancer tissues. Furthermore, we treated OPN to primary cultures of endothelial cells to investigate the EndoMT-inducing activity and the underlying mechanisms. Integrin αVβ3 rather than CD44 is involved in OPN-induced EndoMT. OPN-integrin αVβ3 engagement induces HIF-1α expression through a PI3K/Akt/TSC2-mediated and mTORC1-dependent protein synthesis pathway, which in turn trans-activates TCF12 gene expression. TCF12 further interacts with EZH2 and histone deacetylases to transcriptionally repress VE-cadherin gene and thus facilitates EndoMT. Like cancer-associated fibroblasts, EndoMT-derived cells promote tumor growth and metastasis by secreting certain proteins. Secreted HSP90α is a candidate suggested by microwestern array assay, and is herein verified to induce stemness properties in colorectal cancer cells. As OPN is overexpressed in human cancers, OPN-induced EndoMT and EndoMT-derived cells can be potentially taken as cancer therapeutic targets.

A simple and versatile route for modifying picolinate ligands coordinated to iridium is described. Reacting a μ-chloro iridium(C∧N) dimer (where C∧N is a phenylpyridine-based ligand) with bromopicolinic acid (HpicBr) yields the corresponding iridium(C∧N)2(picBr) complexes (1–4 and 11), which were readily modified by a Sonogashira reaction to give eight alkyne-substituted picolinate complexes (5–10, 12, and 13). The luminescent behavior of these complexes shows that the position of substitution about the picolinate ring has an effect on both photophysical behavior as well as the reactivity.

Cisplatin is a potent anti-cancer drug, however, its accompanied organ-toxicity hampers its clinical applications. Cisplatin-associated kidney injury is known to result from its accumulation in the renal tubule with excessive generation of reactive oxygen species. In this study, we encapsulated honokiol, a natural lipophilic polyphenol constituent extracted from Magnolia officinalis into nano-sized liposomes (nanosome honokiol) and examined the in vivo countering effects on cisplatin-induced renal injury. We observed that 5 mg/kg body weight. nanosome honokiol was the lowest effective dosage to efficiently restore renal functions of cisplatin-treated animals. The improvement is likely due the maintenance of cellular localization of cytochrome c and thus preserves mitochondria integrity and their redox activity, which as a consequence, reduced cellular oxidative stress and caspase 3-associated apoptosis. These improvements at the cellular level are later reflected on the observed reduction of kidney inflammation and fibrosis. In agreement with our earlier in vitro study showing protective effects of honokiol on kidney cell lines, we demonstrated further in the current study, that nanosuspension-formulated honokiol provides protective effects against cisplatin-induced chronic kidney damages in vivo. Our findings not only benefit cisplatin-receiving patients with reduced renal side effects, but also provide potential alternative and synergic solutions to improve clinical safety and efficacy of cisplatin treatment on cancer patients.

Erbium-doped magnesium zinc oxides were prepared through spray pyrolysis deposition at 450 &deg, C with an aqueous solution containing magnesium nitrate, zinc acetate, erbium acetate, and indium nitrate precursors. Diodes with different erbium-doped magnesium zinc oxide thicknesses were fabricated. The effect of erbium-doped magnesium zinc oxide was investigated. The crystalline structure and surface morphology were analyzed using X-ray diffraction and scanning electron microscopy. The films exhibited a zinc oxide structure, with (002), (101), and (102) planes and tiny rods in a mixed hexagonal flakes surface morphology. With the photoluminescence analyses, defect states were identified. The diodes were fabricated via a metallization process in which the top contact was Au and the bottom contact was In. The current&ndash, voltage characteristics of these diodes were characterized. The structure resistance increased with the increase in erbium-doped magnesium zinc oxide thickness. With a reverse bias in excess of 8 V, the light spectrum, with two distinct green light emissions at wavelengths of 532 nm and 553 nm, was observed. The light intensity that resulted when using a different operation current of the diodes was investigated. The diode with an erbium-doped magnesium zinc oxide thickness of 230 nm shows high light intensity with an operational current of 80 mA. The emission spectrum with different injection currents for the diodes was characterized and the mechanism is discussed.

In this study, the spray pyrolysis method was used to prepare unintentionally doped and nitrogen-doped calcium zinc oxide films by using zinc acetate, calcium nitrate precursor, and ammonium acetate precursor. Morphological and structural analyses were conducted using scanning electron microscopy and X-ray diffraction. The results indicated that film grain size decreased as the nitrogen doping was increased. Both calcium oxide and zinc oxide structures were identified in the unintentionally doped calcium zinc oxide. When nitrogen doping was introduced, the film mainly exhibited a zinc oxide structure with preferred (002) and (101) orientations. The concentration and mobility were investigated using a Hall measurement system. P-type films with a mobility and concentration of 10.6 cm 2 V −1 s −1 and 2.8×10 17 cm −3 , respectively, were obtained. Moreover, according to a temperature-dependent conductivity analysis, an acceptor state with activation energy 0.266 eV dominated the p-type conduction for the unintentionally doped calcium zinc oxide. By contrast, a grain boundary with a barrier height of 0.274–0.292 eV dominated the hole conduction for the nitrogen-doped calcium zinc oxide films.

A study of the dark-blue insoluble precipitate that makes up gall ink using bamboo nib-spray mass spectrometry (PS-MS) is described. A ferrous tannate complex is formed, i.e. an insoluble organic metal complex - iron gallate ink (IGI) is produced when tannin is mixed with iron sulfate. Since it is not possible to detect this IGI precipitate by conventional electrospray ionization (ESI) mass spectrometry, we report on an attempt to resolve this problem by a new method in this study in an. The method involved “two steps” using bamboo nib-spray/MS. A gallic acid solution was initially used as a model sample and the ESI mode was operated under a negative voltage. This approach permitted the optimized position between the spray-tip and the mass inlet (either distance or angle) to be determined. Following this, the ESI applied voltage was changed to positive and, at this moment, a ferrous sulfate solution was added to the spray-tip, both reactants are sprayed out immediately and are simultaneously ionized while a complex binding reaction occurs. This permits the IGI dark-blue insoluble precipitate to be ionized and detected. As a result, several specific peaks could be observed. The resulting m/z = 153, 225, 243, 431 peaks are assigned to [C7H5O4]+, [C7H5O5Fe]+, [C7H5O5Fe‧H2O]+, and [(C6H3O3) (C6H4O3)Fe2‧4H2O]+, respectively.

Diodes with an erbium and nitrogen codoped magnesium zinc oxide (MgZnO:Er,N) active layer were fabricated by spray pyrolysis on Si substrate with aqueous solutions including magnesium nitrate, zinc acetate, erbium acetate, ammonium acetate, and indium nitrate precursors. Diodes with different nitrogen content in their precursor were prepared and their properties were investigated. With scanning electron microscopy, film surface with mixed hexagonal flakes and tiny blocks was characterized for all samples. Certain morphologies varied for samples with different N contents. In the photoluminescence analyses, the intensity of the oxygen-related defects peak increased with the increasing of nitrogen content. The diodes were fabricated with an Au and In deposition on the top and backside. The diode current&ndash, voltage as well as capacitance&ndash, voltage characteristics were examined. An ununiformed n-type concentration distribution with high concentration near the interface in the MgZnO:Er,N layer was characterized for all samples. Diodes with high nitrogen content exhibit reduced breakdown voltage and higher interface concentration characteristics. Under reversed bias conditions with an injection current of 50 mA, a light spectrum with two distinct green emissions around wavelengths 532 and 553 nm was observed. A small spectrum variation was characterized for diodes prepared from different nitrogen content. The diode luminescence characteristics were examined and the diode prepared from N/Zn=1 in the precursor showed an optimal injection current-to-luminescence property. The current and luminescence properties of the diode were characterized and discussed.

Improving the spatial alignment of emitting molecules has long been a goal of organic-light-emitting-diode development to improve device efficiencies and to generate polarized emission. Herein we describe a simple approach employing Sonogashira coupling with alkyne iridium(phenylpyridine)2(acetylacetone) synthons (2-5) to generate eight linear iridium complexes (6-13) with crystallographically determined lengths of up to 5 nm. By embedding these "long" complexes into a polymer matrix and stretching it, an improvement of the polarization ratio of unstretched and stretched films of up to 7.1 times was achieved. Additionally, through the inclusion of "twists" in the complexes, the electronic coupling between the iridium center and substituent was controlled, giving a system where the emission behavior is independent of the length.

We detected a significant elevation of serum HSP90α levels in pancreatitis patients and even more in pancreatic ductal adenocarcinoma (PDAC) patients. However, there was no significant difference in the serum HSP90α levels between patients with early-stage and late-stage PDAC. To study whether elevation of serum HSP90α levels occurred early during PDAC development, we used LSL-KrasG12D/Pdx1-Cre transgenic mice as a studying model. Elevated serum HSP90α levels were detected before PDAC formation and an extracellular HSP90α (eHSP90α) inhibitor effectively prevented PDAC development. Both serum HSP90α level and pancreatic lesion were suppressed when the mice were administered a CD11b-antagonizing antibody, suggesting that CD11b+-myeloid cells were associated with eHSP90α levels and pancreatic carcinogenesis. Consistently, in CD11b-DTR-EGFP transgenic mouse model with CD11b+-myeloid cells depletion, serum HSP90α levels were suppressed and Panc-02 cell grafts failed to develop tumors. Macrophages and granulocytes are two common tissue-infiltrating CD11b+-myeloid cells. Duplex in situ hybridization assays suggested that macrophages were predominant HSP90α-expressing CD11b+-myeloid cells during PDAC development. Immunohistochemical and immunohistofluorescent staining results revealed that HSP90α-expressing cells included not only macrophages but also pancreatic ductal epithelial (PDE) cells. Cell culture studies also indicated that eHSP90α could be produced by macrophages and macrophage-stimulated PDE cells. Macrophages not only secreted significant amount of HSP90α, but also secreted interleukin-6 and interleukin-8 to induce a JAK2−STAT3 signaling axis in PDE cells, stimulating them to express and secrete HSP90α. eHSP90α further promoted cellular epithelial-mesenchymal transition, migration, and invasion in PDE cells. Besides myeloid cells, eHSP90α can be potentially taken as a target to suppress PDAC pathogenesis.

The potential of intramolecular π-π interactions to influence the photophysical properties of diiridium complexes is an unexplored topic, and provides the motivation for the present study. A series of diarylhydrazide-bridged diiridium complexes functionalised with phenylpyridine (ppy)-based cyclometalating ligands is reported. It is shown by NMR studies in solution and single crystal X-ray analysis that intramolecular π-π interactions between the bridging and cyclometalating ligands rigidify the complexes leading to high luminescence quantum efficiencies in solution and in doped films. Fluorine substituents on the phenyl rings of the bridge promote the intramolecular π-π interactions. Notably, these non-covalent interactions are harnessed in the rational design and synthesis of the first examples of highly emissive sky-blue diiridium complexes featuring conjugated bridging ligands, for which they play a vital role in the structural and photophysical properties. Experimental results are supported by computational studies.

Aminopeptidase P, a metalloprotease, targets Xaa-Proline peptides for cleavage [1-4]. There are two forms of human AMPP, a membrane-bound form (hmAMPP) and a soluble cytosolic form (hcAMPP)[5]. Similar to the angiotensin-I-converting enzyme, AMPP plays an important role in the catabolism of inflammatory and vasoactive peptides, known as kinins. The plasma kinin, bradykinin, was used as the substrate to conduct enzymatic activity analyses and to determine the Michaelis constant (Km) of 174 μM and the catalytic rate constant (kcat) of 10.8 s-1 for hcAMPP. Significant differences were observed in the activities of Y527F and R535A hcAMPP mutants, which displayed a 6-fold and 13.5-fold for decrease in turnover rate, respectively. Guanidine hydrochloride restored the activity of R535A hcAMPP, increasing the kcat/Km 20-fold, yet it had no impact on the activities of the wild-type or Y527F mutant hcAMPPs. Activity restoration by guanidine derivatives followed the order guanidine hydrochloride >> methyl-guanidine > amino-guanidine > N-ethyl-guanidine. Overall, the results indicate the participation of R535 in the hydrogen bond network that forms a proton relay system. The quaternary structure of hcAMPP was determined by using analytical ultracentrifugation (AUC). The results show that alanine replacement of Arg535 destabilizes the hcAMPP dimer and that guanidine hydrochloride restores the native monomer-dimer equilibrium. It is proposed that Arg535 plays an important role in hcAMMP catalysis and in stabilization of the catalytically active dimeric state.

A series of diiridium complexes 13–16 bridged by diarylhydrazine ligands and cyclometalated by phenylpyridine or phenylpyrazole ligands was synthesized. In all cases the ΛΔ meso and ΛΛ/ΔΔ rac diastereomers were separated and characterized by single-crystal X-ray diffraction, revealing intramolecular π–π stacking between arenes of the bridging and cyclometalating ligands. Density functional theory (DFT) calculations show that in general the HOMOs are mainly localized on the iridium centers, the cyclometalating phenyl moieties, and the central hydrazide components of the bridging ligands, while the LUMOs are primarily localized on the N-heterocycles (pyridine or pyrazole) of the cyclometalating ligands. This series of complexes, especially with the separated diastereomers, provides an ideal opportunity to study the effects of subtle structural changes on the optoelectronic properties of diiridium systems: significant differences are observed between the rac and meso isomers in some cases. A cyclic voltammetric study of the electrochemical properties of the eight complexes reveals strong intramolecular interactions between the iridium centers. The photophysical properties are reported in solution and in rigid poly(methyl methacrylate) (PMMA) and 2-methyltetrahydrofuran (2-MeTHF) (at 77 K) matrices, where some of the complexes are strongly emissive in the turquoise and green regions (ΦPL = 42–68 ± 10%) due to matrix-induced restricted intramolecular motion (RIM).

Aerosol from the burning two types of sandalwood-based incense, Hsing Shan and Lao Shan , was analyzed to characterize the chemical profile of total particulate matter emitted. The total particulate matter (PM) mass emission factors were 46.3 ± 2.68 mg g −1 of Hsing Shan incense and 43.7 ± 1.08 mg g −1 of Lao Shan incense. Chemical analysis of emissions from the two types of incense revealed that of the 25 components in four groups characterized, anhydrosugars formed the major group, at 46.7–52.2% w/w of the identified particulate and 1078.3–1169.8 μg g −1 of incense, followed by inorganic salts at 30.4–31.8% w/w of identified particulate and 681.6–734.0 μg g −1 of incense, carboxylic acids at 12.0–17.1% w/w of the identified particulate and 268.6–392.8 μg g −1 of incense, and sugar alcohols at 4.44–5.38% w/w of the identified particulate and 102.3–120.6 μg g −1 of incense. More anhydrosugars and sugar alcohols were emitted from Lao Shan incense than from Hsing Shan incense whereas more carboxylic acids and organic salts were emitted from Hsing Shan than from Lao Shan . These differences were due to structural and functional differences in the young sandalwood used to make Hsing Shan and the aged sandalwood used to make Lao Shan . The anhydrosugar levoglucosan, used as a marker of biomass burning, was always the most abundant species in emitted PM for both incenses ( Lao Shan 21.7 mg g −1 of PM and Hsing Shan 18.7 mg g −1 ). K + and Cl − were the second most abundant components (K + and Cl − were summed), accounting for 10.6 mg g −1 of Hsing Shan PM and 9.85 mg g −1 of Lao Shan PM. The most abundant carboxylic acids in the emissions were formic, acetic, succinic, glutaric and phthalic acid. The latter is a fragrance ingredient and a potential health hazard and was twice as prevalent in Lao Shan emissions. Xylitol was the most prevalent of the sugar alcohols at 35.7–36.6% w/w of total identified sugar alcohols. These abundant species are potential markers for incense burning. K + , levoglucosan, mannosan and xylitol are already reported in discriminator ratios for wood burning and it is proposed here that these can and should also apply to incense burning. The calculated discriminator ratios for two types of incense burning reported here are 0.229–0.288 for K/Levo, 12.5–13.5 for Levo/Manno, and 21.5–23.7 for the novel discriminator ratio Levo/Xylitol.

Until now, there is no optimal technique for repairing oronasal fistula in patients with prior head and neck radiotherapy and trismus. Use of the silicone button is a safe, office-based, and validated method in this situation. The indications of this procedure are also clarified in this study. This is a retrospective study of four patients who underwent a newly designed endoscopic repair of oronasal fistula with silicone button under local anesthesia from July 2012 to August 2012. Data on the size of the defect, length of operation, symptom relief, and post-operative complications were collected. Four patients underwent endoscopic repair of oronasal fistula with silicone button under local anesthesia. The diagnoses were benign palate lesion s/p operation, oral cancer s/p operation and radiotherapy. The defect diameter varied from 1 to 1.5 cm. The operation durations were between 20 and 30 min. In all cases, nasal regurgitation symptoms were relieved. The hypernasality of one case improved, while another had decreased nasal crusting and foul odors. No major complications were noted. There was a minor complication in one case, which exhibited frequent crusting around the silicone button. Silicon button can act as a temporary obturator to improve quality of life of patients. The indications for this procedure include patient undergone head and neck radiotherapy with (1) chronic fistula (>6 months); (2) small defect (1–2 cm); and (3) trismus. Level of evidence: 4.

ZnO thin film was fabricated by thermally oxidized Zn at 600°C for 1 h. A surface containing nanostructured dumbbell and lines was observed by scanning electron microscope (SEM). The ZnO resistor device was formed after the following Ti/Au metallization. The device resistance was characterized at different oxygen pressure environment in the dark and under ultraviolet (UV) light illumination coming from the mercury lamp with a short pass filter. The resistance increases with the increase of oxygen pressure. The resistance decreases and response increases with the increase of light intensity. Models considering the barrier height variation caused by the adsorbed oxygen related species were used to explain these results. The UV light illumination technology shows an effective method to enhance the detection response for this ZnO resistor oxygen sensor.

Epitaxies of AlGaN/AlN/GaN high electron mobility transistor (HEMT) structures with different thickness of nano-scale AlN interlayers have been realized by metalorganic chemical vapor deposition (MOCVD) technology. After epitaxy, high resolution X-ray diffraction (HRXRD), temperature-dependent Hall Effect and atomic force microscopy (AFM) measurements were used to characterize the properties of these samples. First, it was found that the Al composition of AlGaN layer increases from 21.6 to 34.2% with increasing the thickness of AlN interlayer from 0 to 5 nm under the same AlGaN growth conditions. This result may due to the influences of compressive stress and Al incorporation induced by the AlN interlayer. Then, we also found that the room-temperature (RT) electron mobility stays higher than 1500 cm 2 /Vs in the samples within AlN interlayer thickness range of 1.5 nm, on the other hand, the low-temperature (80K) electron mobility drops dramatically from 8180 to 5720 cm 2 /Vs in the samples with AlN interlayer thickness increasing from 1 to 1.5 nm. Furthermore, it was found that the two-dimensional electron gas (2DEG) density increases from 1.15×10 13 to 1.58×10 13 cm -2 beyond the AlN interlayer thickness of 1 nm. It was also found that the temperature independent 2DEG densities are observed in the samples with AlN interlayer thickness of 0.5 and 1 nm. The degenerated characteristics of the samples with AlN thickness thicker than 1.5 nm show the degraded crystalline quality which matched the observation of surface defects and small cracks formations from their AFM images. Finally, the 2DEG mobilities of the proposed structures can be achieved as high as 1705 and 8180 cm 2 /Vs at RT and 80K, respectively.

Thin film samples of (Cu,Ga)InSe 2 (CIGS) were prepared by DC magnetron sputtering and the selenisation process onto soda lime glass substrates. All samples had the same deposition conditions, and the optimal sputtering thickness of samples with one CuGa/In pair and two CuGa/In pairs are also the same. After sample deposition, X-ray diffraction (XRD), scanning electron microscope (SEM) and Hall effect measurements were used to characterize the properties of these samples. From XRD measurement results, excepting an extra small CuSe peak existing in the samples with two CuGa/In pairs, the XRD peaks of all samples are perfectly matched with the phase diagram of CuGa 0.3 In 0.7 Se 2 material. It was also found that the grain sizes of the samples with one CuGa/In pair are larger than those with two CuGa/In pairs from SEM images. All these observations on samples with two CuGa/In pairs can be attributed to the fact that the less In incorporation in CIGS films, which it has been proven that the sample with low In-to-CuGa ratio has stronger CuSe peak from XRD result. Furthermore, the p-type carrier characteristics can be observed for all samples from Hall measurement results. The carrier mobility and concentration of the samples with one CuGa/In pair can be achieved as high as 15.28 cm 2 /Vs and as low as 1.50×10 16 cm -3 , respectively, while the carrier mobility and concentration of the ones with two CuGa/In pairs can be achieved as 6.4 cm 2 /Vs and 6.27×10 17 cm -3 , respectively. The results of superior electrical properties of samples with one CuGa/In pair agree well with the observations form XRD and SEM results. In the final, the optimal value of In-to-CuGa ratio during CuGa/In layers deposition in this study is 0.625.

Boron doping on the structural, optical and electrical properties in BZO films fabricated by spray pyrolysis were investigated. The carrier concentration of ∼1019cm−3 and optical transmittance about 90% in the infrared region was achieved.

Thin films of Cuprous Oxide (Cu 2 O) with different deposition temperatures have been deposited on glass substrates by spray pyrolysis. The films were investigated in terms of morphological surface, structural and electrical properties exhibited p-type conduction.

A new type of competitive human GST inhibitors has been developed via the bioisostere and structure activity profile strategies; we report their discovery, preparation, inhibitory activity, and synergetic effect in combination with chemotherapy drugs against breast cancer cells.

An enzyme capable of hydrolyzing organophosphate compounds is of biological as well as environmental significance. We evaluated the possibility of human cytosolic aminopeptidase P (hcAMPP) as an attractive bioscavenger candidate by measuring the enzymatic rates of hydrolysis for a wide variety of organophosphorus compounds. The comparison of substrate specificity exhibited by hcAMPP and E. coli aminopeptidase P (E. coli AMPP) was studied. We cloned, expressed, and purified hcAMPP from HeLa cells and AMPP from Escherichia coli. The pH-rate profiles of hcAMPP were measured in the presence of organophosphate compound 3 or 5. All of the organophosphorus compounds, 1-19, were synthesized by using the approach of phosphorus chemistry described in a previous publication. The relative activity of hcAMPP and E. coli AMPP in hydrolyzing a series of organophosphorus analogues, 1-17, was evaluated in a spectrophotometric assay by monitoring the difference of accumulation of 4-nitrophenol at 400 nm. The overall substrate preference of hcAMPP is as follows: methylphosphonates>ethylphosphonates> or =organophosphates. Interestingly, the observed enhancement in the activity of hcAMPP with methyl phosphonates, 8, 10, 12, and 13, suggests that there is particularly special about the substructure of both methyl moiety and P=O ligand, since the values of specific activity with hcAMPP for the methylphosphonates 8, 10, 12, and 13 are 2- to 73-fold greater than those for the ethylphosphonates 14-17 and the organophosphates 1-7. Similarly, in E. coli AMPP toward ethylphosphonates 14-17, the results indicate that the regions of both MeO moiety and P=O ligand may be located in the vicinity of the substrate-binding site, which have not been altered within the active site of enzyme upon mutation of Trp88, Arg153, and Arg370. These studies demonstrate that E. coli AMPP and hcAMPP display different substrate preference toward organophosphorus compounds. Evidence here, therefore, represents the first example of hcAMPP that might serve as a valuable bioscavenger candidate as E. coli AMPP due to the promise from the hydrolysis of these toxic chemicals.

A primary pathway for metabolism of electrophilic compounds in Schistosoma japonicum involves glutathione S-transferase (SjGST)-catalyzed formation of glutathione (GSH) conjugates. As part of a program aimed at gaining a better understanding of the defense system of parasites, a series of aromatic halides (1-8), aliphatic halides (9, 10), epoxides (11-20), alpha,beta-unsaturated esters (21, 22), and alpha,beta-unsaturated amides (23, 24) were prepared, and their participation in glutathione conjugate formation was evaluated. Products from enzymatic and nonenzymatic reactions of these substances with glutathione were characterized and quantified by using reverse-phase high-performance liquid chromatography (HPLC), NMR, and fast atom bombardment mass spectrometry (FAB-MS) analysis. Mechanisms for formation of specific mono(glutathionyl) or bis(glutathionyl) conjugates are proposed. Although the results of this effort indicate that SjGST does not catalyze addition or substitution reactions of 1, 3, 4, 7-9, 11-13, 15-17, 19-21, and 24, they demonstrate that 2, 5, 6, 14, 18, and 23 undergo efficient enzyme-catalyzed conjugation reactions. The kcat values for SjGST with 23 and 18 are about 886-fold and 14-fold, respectively, larger than that for 5. This observation suggests that 23 is a good substrate in comparison to other electrophiles. Furthermore, the initially formed conjugation product, 23a, is also a substrate for SjGST in a process that forms the bis(glutathionyl) conjugate 23b. Products arising by enzymatic and nonenzymatic pathways are generated under the conditions of SjGST-activated GSH conjugation. Interestingly, production of nonenzymatic GSH conjugates with electrophilic substrates often overwhelms the activity of the enzyme. The nonenzymatic GSH conjugates, 9a-11a, 16a, 21a, and 22a, are inhibitors of SjGST with respective IC50 values of 1.95, 75.5, 0.96, 19.0, 152, and 0.36 microM, and they display moderate inhibitory activities against human GSTA2. Direct evidence has been gained for substrate inhibition by 10 toward SjGST and GSTA2 that is more potent than that of its GSH conjugate 10a. The significance of this work is found in the development of a convenient NMR-based technique that can be used to characterize glutathione conjugates derived from small molecule libraries as part of efforts aimed at uncovering specific potent SjGST and GSTA2 inhibitors. This method has potential in applications to the identification of novel inhibitors of other GST targets that are of chemotherapeutic interest.

Boron-doped zinc oxide (BZO) thin films have been fabricated by spray pyrolysis on a glass substrate. The morphology and electrical properties of the thin films were investigated. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses were performed. It was found that [B]/[Zn] ratio altered both the microstructure and concentration of the BZO thin films. The film grain size was reduced by increasing the [B]/[Zn] ratio. The highest Hall mobility was 3.65 cm2 V-1 s-1 for the undoped ZnO thin film, and the highest carrier concentration of 1.0×1019 cm-3 was achieved for the as-deposited BZO thin film with [B]/[Zn] = 1.5 at. %. Conductivity was determined at different measurement temperatures and shallow donors provided the dominate conduction mechanism for the as-deposited BZO thin films. After 600 °C annealing, shallow level reduction and donors with a high activation energy of 129±6 meV in the BZO thin films were characterized, and the shallow donors that dominate the carrier concentration for the as-deposited spray-pyrolized BZO thin film were eliminated.