A novel transparent Al-doped ZnO (AZO)-gated Al 0.2 Ga 0.8 As/In 0.2 Ga 0.8 As pseudomorphic high-electron mobility transistor (pHEMT) has been comprehensively investigated. The proposed AZO-gated ...pHEMT has demonstrated superior temperature-dependent performance, including two-terminal gate-drain breakdown/turn-on voltages of - 63/3.4 (-56.4/3.4) V, an intrinsic voltage gain A V of 257 (176), and a gate voltage swing of 1.18 (1.13) V at 300 (450) K. An excellent thermal threshold coefficient ∂V th /ΘT of -1.8 mV/K was also obtained. A conventional Au-gated device with the same gate dimensions of 1 × 100 μm 2 was also fabricated in comparison. In addition, high optical transmittance values of 82%-98% for incident energy values of 1.24-3.54 eV are achieved in the AZO film. The present AZO-gated HEMT has demonstrated three-terminal tunable optical responsivity due to a photovoltaic effect. Photosensing characteristics under different radiation wavelengths of white light, red light (632 nm), and near infrared (980 nm) are also studied.
Deoxygenation of microalgal oil obtained by pyrolysis of microalgae was carried out for the production of hydrocarbon fuel from biomass by metal supported catalyst. Oleic acid was used as a model ...reactant to select an optimized catalyst. Effects of support, metal species, and metal loading on catalytic performance were investigated. Activated carbon showed better performance than silica as a support. Considering various factors in model reaction, such as metal loading, reaction temperature, activity for deoxygenation, and selectivity for decarboxylation, 5wt% platinum supported on activated carbon (5wt% Pt/C) was selected as an optimized catalyst. Based on these results, deoxygenation of the pyrolysis oil from Chlorella sp. KR-1 was conducted at 623 and 673K over this selected catalyst. The product after catalytic deoxygenation was mainly composed of pure hydrocarbons, and its oxygen content was below 2.0%. The fraction in the product of which the boiling point was less than 623K was about 90%. These properties could allow this upgraded oil to be used for transportation fuel. However, the degree of oxygen removal with microalgal pyrolysis oil was lower than that with oleic acid, implying that impurities in the pyrolysis oil may inhibit the deoxygenation reaction.
▸ For the transportation fuels production, deoxygenation of pyrolysis oil from microalgae using precious metal catalysts was investigated. ▸ The optimized catalyst for the dexoygenation of model reactant, oleic acid, was 5wt% Pt/C. ▸ The optimized catalyst, 5wt% Pt/C, showed reasonable catalytic activity for the deoxygenation of pyrolysis oil.
Volatile formation is an inevitable result of lipid oxidation, which impact the quality of lipid rich foods. In this study, moisture role on the formation of volatiles were evaluated using deuterium ...oxide (D
2
O) and possible steps of moisture involvement were suggested. Moisture content in corn oil with deuterium free water (H
2
O) was significantly (
p
< 0.05) higher than that in corn oil with D
2
O. The contents of some volatiles including pentane, hexanal, 2-hexenal, and
t
-2-heptenal in corn oil with D
2
O were higher than those in corn oil with H
2
O for the first 8 days. Volatiles containing deuterium appeared in the order of pentane,
t
-2-pentenal, and
t
-2-heptenal during oxidation. Deuterium incorporated volatiles could be formed after the β-scission of lipid hydroperoxides. Therefore, moisture plays important roles in the formation of volatiles as well as the locations of oxidation in bulk oils.
Polyfunctionality is a hallmark of protective immunity, yet the molecular mechanisms governing polyfunctional T cells are poorly understood. After TCR activation, naïve CD8+ T cells undergo ...proliferation and differentiation, which lead to effector functions and memory subset development. However only a portion of activated T cells develop into memory CD8+ T cells and with chronic stimulation become terminally differentiated and exhausted CD8+ T cells, as defined by CCR7-/CD45RA+, and functionally impair effective immune responses 1. We therefore probed the ability to reverse terminally differentiated antigen-specific cells using pharmacological agents. Stimulating human memory CD8+ T cells with cognate TCR stimulation in the presence of Wnt agonist enhances polyfunctionality and stemness. Both M1-influenza+ and CMV+ CD8+ T cell responses were reprogrammed and revealed sustained effects from initial Wnt pathway activation in vitro. Future work with cancer antigens and reprogramming of differentiated CD8+ responses could lead to improved in vitro culture conditions for adoptive immunotherapy.
This work provides comparative studies of AlGaN/GaN MOS-HEMT with the devised stacked La2O3/Al2O3 dielectric structure with respect to a conventional Schottky-gate HEMT and a reference ...La2O3-dielectric MOS-HEMT, which were all fabricated on the identical epitaxial layers. The La2O3/Al2O3 stacked dielectrics are formed by using RF magnetron sputter/H2O2 oxidization. Transmission electron microscopy (TEM), capacitance-voltage (C-V) measurement with different frequency, and low-frequency noise (LFN) analysis were used to study the interface and oxide quality. Comprehensive studies on electrical and thermal stability characteristics have been performed. Improved transconductance gain (gm), current drive, breakdown, and thermal stability at 300-480 K are achieved in the present MOS-HEMT design.
Comparative studies of double δ-doped InAlAs/InGaAs metal-oxide-semiconductor metamorphic high electron mobility transistors (MOS-MHEMTs) with different compressive-strained and tensile-strained ...channel structures have been made. In addition to the strain engineering of the heterostructure, the MOS-gate design is also integrated by using the cost-effective H2O2 oxidization technique. The tensile (compressive)-strained channel is devised by the In0.52Al0.48As/In0.41Ga0.59As (In0.52Al0.48As/In0.63Ga0.37As) heterostructure. Device characteristics with respect to different channel structures are physically studied. The impact-ionization-related kink effects in MHEMTs are significantly suppressed by the MOS-gate. Atomic force microscopy (AFM) and low-frequency noise (LFN) analysis were used to study the surface roughness and interface quality. As compared to the compressive-strained MOS-MHEMT and conventional Schottky-gate devices, the present tensile-strained MOS-MHEMT design has demonstrated improved transconductance gain (gm), current drive, intrinsic voltage gain (AV), and power performance.
T cell polyfunctionality is a hallmark of protective immunity against pathogens and cancer, yet the molecular mechanism governing it remains mostly elusive. We found that canonical Wnt agonists ...inhibited human memory CD8+ T cell differentiation while simultaneously promoting the generation of highly polyfunctional cells. Downstream effects of Wnt activation persisted after removal of the drug, and T cells remained polyfunctional following subsequent cell division, indicating the effect is epigenetically regulated. Wnt activation induced a gene expression pattern that is enriched with stem cell-specific gene signatures and upregulation of protein arginine methyltransferase 1 (PRMT1), a known epigenetic regulator. PRMT1+CD8+ T cells are associated with enhanced polyfunctionality, especially the ability to produce IL-2. In contrast, inhibition of PRMT1 ameliorated the effects of Wnt on polyfunctionality. Chromatin immunoprecipitation revealed that H4R3me2a, a permissive transcription marker mediated by PRMT1, increased at the IL-2 promoter loci following Wnt activation. In vivo, Wnt-treated T cells exhibited superior polyfunctionality and persistence. When applied to cytomegalovirus (CMV) donor-seropositive, recipient-seronegative patients (D+/R-) lung transplant patient samples, Wnt activation enhanced CMV-specific T cell polyfunctionality, which is important in controlling CMV diseases. These findings reveal a molecular mechanism governing T cell polyfunctionality and identify PRMT1 as a potential target for T cell immunotherapy.
Abstract
Polyfunctionality, a single T cell producing a set of different effector molecules, is a hallmark of protective immunity against infection and tumor, but the molecular pathways governing the ...polyfunction T cells were not well known. In our lab, we found that memory CD8 T cells treated with TWS119, a Wnt pathway activator, increased highly polyfunctional memory T cells formation during expansion. The treatment of TWS119 enhanced CD62L+, CD28+ and KLRG1- central memory T cell phenotype. We further analyzed the impact of Wnt activation on influenza virus or CMV(cytomegalovirus) antigen-specific stimulation, and found TWS119 also improved the polyfunctionality. Especially in CMV-specific T cells, terminal differentiated non-polyfunctional population, Wnt signaling reversed their non polyfunctional state. Wnt-activated T cells were capable of superior homeostatic proliferation and expressed more anti-apoptotic molecules. Mechanistically, RNA microarray analysis revealed that Wnt activation led the gene expression profile correlated with stem-cell specific gene expression pattern. Our findings provided the evidence that non-polyfunctional antigen-specific human CD8 T cells response can be pharmacologically reprogrammed and have important translational implications for immunotherapy against chronic viral infections and malignancies.
Abstract
Cytomegalovirus (CMV) infection is one of the most common persistent viral infections in humans worldwide and is epidemiologically associated with many adverse health consequences during ...aging. Previous studies yielded conflicting results regarding whether large, CMV-specific T-cell expansions maintain their function during human aging. In the current study, we examined the in vitro CMV-pp65-reactive T-cell response by comprehensively studying five effector functions (i.e., interleukin-2, tumor necrosis factor-α, interferon-γ, perforin, and CD107a expression) in 76 seropositive individuals aged 70 years or older. Two data-driven, polyfunctionality panels (IL-2-associated and cytotoxicity-associated) derived from effector function co-expression patterns were used to analyze the results. We found that, CMV-pp65-reactive CD8+ and CD4+ T cells contained similar polyfunctional subsets, and the level of polyfunctionality was related to the size of antigen-specific response. In both CD8+ and CD4+ cells, polyfunctional cells with high cytotoxic potential accounted for a larger proportion of the total response as the total response size increased. Notably, a higher serum CMV-IgG level was positively associated with a larger T-cell response size and a higher level of cytotoxic polyfunctionality. These findings indicate that CMV-pp65-specific CD4+ and CD8+ T cell undergo simultaneous cytotoxic polyfunctionality maturation during aging.
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