Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 41
Filtrar
Más filtros

Banco de datos
Tipo del documento
Intervalo de año de publicación
1.
Appl Microbiol Biotechnol ; 105(1): 67-76, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33191460

RESUMEN

Our previous work showed that there is a limitation in the use of dihydrofolate reductase (dhfr)/methotrexate (MTX)-mediated gene amplification systems in dhfr-non-deficient HEK293 cells, as endogenous dhfr may interfere with the amplification process. In the present study, we successfully generated Epstein-Barr virus nuclear antigen-1 (EBNA-1)-amplified HEK293 cells in a dhfr-non-deficient HEK293 cell background using a single-plasmid vector-based gene amplification system with shRNA targeting the 3'-UTR of endogenous dhfr. The introduction of this shRNA efficiently downregulated the expression of endogenous dhfr in the HEK293 cells without affecting exogenous dhfr expression. The downregulation of endogenous dhfr improved the efficiency of EBNA-1 amplification, as evidenced by a comparison with the amplification extent in cells lacking shRNA expression at the same MTX concentration. The EBNA-1 expression levels from the EBNA-1-amplified clones selected in this study were higher than those obtained from EBNA-1-amplified clones that were generated using the conventional amplification in our previous study. Consistent with previous studies, EBNA-1 amplification improved the production of the Fc-fusion protein through a specific protein productivity (qp)-enhancing effect, rather than by improving cell growth or transfection efficiency. In addition, the N-glycan profiles in the Fc-fusion protein produced using this transient gene expression (TGE) system were not affected by EBNA-1 amplification. These results indicate the potential utility of EBNA-1-amplified mammalian cells, developed using a single-plasmid vector-based gene amplification system, for efficient protein production. KEY POINTS: • EBNA-1-amplified HEK293 cells were established using gene amplification system. • EBNA-1 amplification in TGE system can increase the Fc-fusion protein productivity. • EBNA-1 amplification does not affect the N-glycan profile in the Fc-fusion protein.


Asunto(s)
Infecciones por Virus de Epstein-Barr , Amplificación de Genes , Animales , Células CHO , Cricetinae , Antígenos Nucleares del Virus de Epstein-Barr/genética , Expresión Génica , Células HEK293 , Herpesvirus Humano 4/genética , Humanos , Metotrexato , Plásmidos/genética , Tetrahidrofolato Deshidrogenasa/genética , Tetrahidrofolato Deshidrogenasa/metabolismo
2.
Small ; 14(6)2018 02.
Artículo en Inglés | MEDLINE | ID: mdl-29211321

RESUMEN

Black phosphorus (BP) has drawn enormous attention for both intriguing material characteristics and electronic and optoelectronic applications. In spite of excellent advantages for semiconductor device applications, the performance of BP devices is hampered by the formation of phosphorus oxide on the BP surface under ambient conditions. It is thus necessary to resolve the oxygen-induced degradation on the surface of BP to recover the characteristics and stability of the devices. To solve this problem, it is demonstrated that a 1,2-ethanedithiol (EDT) treatment is a simple and effective way to remove the bubbles formed on the BP surface. The device characteristics of the degraded BP field-effect transistor (FET) are completely recovered to the level of the pristine cases by the EDT treatment. The underlying principle of bubble elimination on the BP surface by the EDT treatment is systematically analyzed by density functional theory calculation, atomic force microscopy, and X-ray photoelectron spectroscopy analysis. In addition, the performance of the hexagonal boron nitride-protected BP FET is completely retained without changing device characteristics even when exposed to 30 d or more in air. The EDT-induced recovering effect will allow a new route for the optimization of electronic and optoelectronic devices based on BP.

3.
FASEB J ; 31(4): 1608-1619, 2017 04.
Artículo en Inglés | MEDLINE | ID: mdl-28069826

RESUMEN

Androgen-deprivation therapy has been identified to induce oxidative stress in prostate cancer (PCa), leading to reactivation of androgen receptor (AR) signaling in a hormone-refractory manner. Thus, antioxidant therapies have gained attention as adjuvants for castration-resistant PCa. Here, we report for the first time that human endostatin (ES) prevents androgen-independent growth phenotype in PCa cells through its molecular targeting of AR and glucocorticoid receptor (GR) and downstream pro-oxidant signaling. This reversal after ES treatment significantly decreased PCa cell proliferation through down-regulation of GR and up-regulation of manganese superoxide dismutase and reduced glutathione levels. Proteome and biochemical analyses of ES-treated PCa cells further indicated a significant up-regulation of enzymes in the major reactive oxygen species (ROS) scavenging machinery, including catalase, glutathione synthetase, glutathione reductase, NADPH-cytochrome P450 reductase, biliverdin reductase, and thioredoxin reductase, resulting in a concomitant reduction of intracellular ROS. ES further augmented the antioxidant system through up-regulation of glucose influx, the pentose phosphate pathway, and NAD salvaging pathways. This shift in cancer cell redox homeostasis by ES significantly decreased the effect of protumorigenic oxidative machinery on androgen-independent PCa growth, suggesting that ES can suppress GR-induced resistant phenotype upon AR antagonism and that the dual targeting action of ES on AR and GR can be further translated to PCa therapy.-Lee, J. H., Kang, M., Wang, H., Naik, G., Mobley, J. A., Sonpavde, G., Garvey, W. T., Darley-Usmar, V. M., Ponnazhagan, S. Endostatin inhibits androgen-independent prostate cancer growth by suppressing nuclear receptor-mediated oxidative stress.


Asunto(s)
Antineoplásicos/farmacología , Proliferación Celular/efectos de los fármacos , Endostatinas/farmacología , Estrés Oxidativo , Neoplasias de la Próstata/metabolismo , Receptores Androgénicos/metabolismo , Catalasa/genética , Catalasa/metabolismo , Línea Celular Tumoral , Regulación hacia Abajo , Glutatión Reductasa/genética , Glutatión Reductasa/metabolismo , Humanos , Masculino , NADPH-Ferrihemoproteína Reductasa/genética , NADPH-Ferrihemoproteína Reductasa/metabolismo , Receptores de Glucocorticoides/metabolismo , Superóxido Dismutasa/genética , Superóxido Dismutasa/metabolismo , Reductasa de Tiorredoxina-Disulfuro/genética , Reductasa de Tiorredoxina-Disulfuro/metabolismo
4.
Appl Microbiol Biotechnol ; 102(11): 4729-4739, 2018 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-29654557

RESUMEN

Despite the relatively low transfection efficiency and low specific foreign protein productivity (qp) of Chinese hamster ovary (CHO) cell-based transient gene expression (TGE) systems, TGE-based recombinant protein production technology predominantly employs CHO cells for pre-clinical research and development purposes. To improve TGE in CHO cells, Epstein-Barr virus nuclear antigen-1 (EBNA-1)/polyoma virus large T antigen (PyLT)-co-amplified recombinant CHO (rCHO) cells stably expressing EBNA-1 and PyLT were established using dihydrofolate reductase/methotrexate-mediated gene amplification. The level of transiently expressed Fc-fusion protein was significantly higher in the EBNA-1/PyLT-co-amplified pools compared to control cultures. Increased Fc-fusion protein production by EBNA-1/PyLT-co-amplification resulted from a higher qp attributable to EBNA-1 but not PyLT expression. The qp for TGE-based production with EBNA-1/PyLT-co-amplified rCHO cells (EP-amp-20) was approximately 22.9-fold that of the control culture with CHO-DG44 cells. Rather than improved transfection efficiency, this cell line demonstrated increased levels of mRNA expression and replicated DNA, contributing to an increased qp. Furthermore, there was no significant difference in N-glycan profiles in Fc-fusion proteins produced in the TGE system. Taken together, these results showed that the use of rCHO cells with co-amplified expression of the viral elements EBNA-1 and PyLT improves TGE-based therapeutic protein production dramatically. Therefore, EBNA-1/PyLT-co-amplified rCHO cells will likely be useful as host cells in CHO cell-based TGE systems.


Asunto(s)
Antígenos Transformadores de Poliomavirus/genética , Antígenos Nucleares del Virus de Epstein-Barr/genética , Amplificación de Genes , Técnicas de Amplificación de Ácido Nucleico/métodos , Animales , Células CHO , Cricetinae , Cricetulus , Proteínas Recombinantes/genética , Transfección
5.
Proc Natl Acad Sci U S A ; 112(5): 1392-7, 2015 Feb 03.
Artículo en Inglés | MEDLINE | ID: mdl-25605930

RESUMEN

Acquired resistance to androgen receptor (AR)-targeted therapies compels the development of novel treatment strategies for castration-resistant prostate cancer (CRPC). Here, we report a profound effect of endostatin on prostate cancer cells by efficient intracellular trafficking, direct interaction with AR, reduction of nuclear AR level, and down-regulation of AR-target gene transcription. Structural modeling followed by functional analyses further revealed that phenylalanine-rich α1-helix in endostatin-which shares structural similarity with noncanonical nuclear receptor box in AR-antagonizes AR transcriptional activity by occupying the activation function (AF)-2 binding interface for coactivators and N-terminal AR AF-1. Together, our data suggest that endostatin can be recognized as an endogenous AR inhibitor that impairs receptor function through protein-protein interaction. These findings provide new insights into endostatin whose antitumor effect is not limited to inhibiting angiogenesis, but can be translated to suppressing AR-mediated disease progression in CRPC.


Asunto(s)
Antagonistas de Andrógenos/metabolismo , Endostatinas/farmacología , Neoplasias de la Próstata/metabolismo , Receptores Androgénicos/metabolismo , Sitios de Unión , Núcleo Celular/metabolismo , Humanos , Masculino
6.
Phys Chem Chem Phys ; 19(7): 5121-5126, 2017 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-28138674

RESUMEN

We propose a novel hybrid structure for improving the efficiency of crystalline silicon solar cells. By employing first-principles calculations, we demonstrate that ordered, nanoporous silicon (np-Si), when filled with polythiophene (PT) inside the pores, exhibits a substantially enhanced absorption coefficient compared to both np-Si and the bulk, which makes the np-Si/PT heterojunction a superior light absorbing material. In addition, the PT-filled porous structure forms a staggered gap, or type II, heterojunction at the interfaces, where the valence band maximum and conduction band minimum of the composite reside on PT and np-Si, respectively. Moreover, the pore-filling polymer brings about a highly dispersive valence band, which provides a major pathway for hole transport. These results suggest that such a hybrid structure, which may be easier to scale up than nanowire-based approaches, will efficiently dissociate photo-induced electron-hole pairs and reduce the amount of material for light absorption, thus leading to a cost-effective and high-performance solar cell.

7.
Prostate ; 76(7): 624-36, 2016 May.
Artículo en Inglés | MEDLINE | ID: mdl-26856684

RESUMEN

BACKGROUND: A growing body of evidence indicates a positive correlation between expression of human antimicrobial peptide leucin leucin 37 (LL-37) and progression of epithelial cancers, including prostate cancer (PCa). Although the molecular mechanisms for this correlation has not yet been elucidated, the primary function of LL-37 as a chemotactic molecule for innate immune effector cells suggests its possible association in coordinating protumorigenic mechanisms, mediated by tumor-infiltrating immune cells. METHODS: To investigate protumorigenic role(s) of cathelicidin-related antimicrobial peptide (CRAMP), a murine orthologue of LL-37, the present study compared tumor growth kinetics between mouse PCa cell lines with and without CRAMP expression (TRAMP-C1 and TRAMP-C1(CRAMP-sh) , respectively) in immunocompetent mice. CRAMP-mediated chemotaxis of different innate immune cell types to the tumor microenvironment (TME) was observed in vivo and confirmed by in vitro chemotaxis assay. The role of CRAMP in differentiation and polarization of immature myeloid progenitors (IMPs) to protumorigenic type 2 macrophages (M2) in TME was determined by adoptive transfer of IMPs into mice bearing CRAMP(+) and CRAMP(-) tumors. To differentiate protumorigenic events mediated by tumor-derived CRAMP from host immune cell-derived CRAMP, tumor challenge study was performed in CRAMP-deficient mice. To identify mechanisms of CRAMP function, macrophage colony stimulating factor (M-CSF) and monocyte chemoattractant protein 1 (MCP-1) gene expression was analyzed by QRT-PCR and STAT3 signaling was determined by immunoblotting. RESULTS: Significantly delayed tumor growth was observed in wild-type (WT) mice implanted with TRAMP-C1(CRAMP-sh) cells compared to mice implanted with TRAMP-C1 cells. CRAMP(+) TME induced increased number of IMP differentiation into protumorigenic M2 macrophages compared to CRAMP(-) TME, indicating tumor-derived CRAMP facilitates differentiation and polarization of IMPs toward M2. Tumor challenge study in CRAMP deficient mice showed comparable tumor growth kinetics with WT mice, suggesting tumor-derived CRAMP plays a crucial role in PCa progression. In vitro study demonstrated that overexpressed M-CSF and MCP-1 in TRAMP-C1 cells through CRAMP-mediated autocrine signaling, involving p65, regulates IMP-to-M2 differentiation/polarization through STAT3 activation. CONCLUSION: Altogether, the present study suggests that overexpressed CRAMP in prostate tumor initially chemoattracts IMPs to TME and mediates differentiation and polarization of early myeloid progenitors into protumorigenic M2 macrophages during PCa progression. Thus, selective downregulation of CRAMP in tumor cells in situ may benefit overcoming immunosuppressive mechanisms in PCa.


Asunto(s)
Péptidos Catiónicos Antimicrobianos/metabolismo , Diferenciación Celular/genética , Polaridad Celular/genética , Quimiotaxis/genética , Macrófagos/metabolismo , Células Progenitoras Mieloides/metabolismo , Neoplasias de la Próstata/metabolismo , Animales , Péptidos Catiónicos Antimicrobianos/genética , Línea Celular Tumoral , Quimiocina CCL2/genética , Quimiocina CCL2/metabolismo , Regulación de la Expresión Génica , Factor Estimulante de Colonias de Macrófagos/genética , Factor Estimulante de Colonias de Macrófagos/metabolismo , Macrófagos/patología , Masculino , Ratones , Células Progenitoras Mieloides/patología , Neoplasias de la Próstata/genética , Neoplasias de la Próstata/patología , Microambiente Tumoral , Catelicidinas
8.
Phys Chem Chem Phys ; 18(31): 21949-53, 2016 Aug 03.
Artículo en Inglés | MEDLINE | ID: mdl-27440199

RESUMEN

The Poisson's ratio νij = -ε/ε, where ε and ε (i,j = x, y, z) are applied and resulting strain, respectively, are computed from first-principles for Si with an array of cylindrical, nanometer-sized pores aligned in the z direction (nanoporous Si, or np-Si). Through density functional theory calculations, it is demonstrated that the periodic arrangement of pores introduces strong anisotropy in the Poisson's ratio of np-Si: while νyz remains close to the Poisson's ratio of the bulk, νzx and νxy exhibit an increase and a sharp decrease from the bulk value, respectively, as the volume fraction of pores (ϕ) becomes large. It is shown that the characteristic dependence of the Poisson's ratio on ϕ originates from the difference in the actual stress on np-Si, which is caused by the dissimilar surface geometry. Unlike random porous materials, this finding signifies the importance of structural details in determining the mechanical response of ordered systems at a nanoscale.

9.
Nano Lett ; 14(9): 5081-4, 2014 Sep 10.
Artículo en Inglés | MEDLINE | ID: mdl-25153784

RESUMEN

Elastic properties of nanoporous Si (np-Si), which is composed of bulk Si containing ordered, nanometer-sized cylindrical pores, are investigated based on first-principles density functional theory calculations. By separately varying the pore size and spacing, it is demonstrated that the elastic stiffness of np-Si under the shear strain perpendicular to the pore axis turns negative when the volume fraction of pores becomes greater than a critical value. The total energy calculations reveal that the negative values in the stiffness originate from the enhanced strain energy, which leads to significant rotation in bonds near the pore surface. Moreover, the high sensitivity of the elastic stiffness to shear induces a structural transformation in np-Si from tetragonal (D2d) to orthorhombic (C2v) phase, which makes it necessary to properly take the effect of external strain due to substrates or electrical leads into account in np-Si-based applications.

10.
Phys Chem Chem Phys ; 16(6): 2425-9, 2014 Feb 14.
Artículo en Inglés | MEDLINE | ID: mdl-24356280

RESUMEN

Increasing demand for energy with fossil fuel supplies decreasing makes it an urgent task to develop novel and cost-effective materials that can supply environmentally benign and sustainable energy. To address this important issue, in the present work we carry out a systematic study on the effect of external strain on the room-temperature thermoelectric properties of Si containing cylindrical pores in a periodic arrangement (nanoporous Si, or np-Si), based on density functional theory and the Boltzmann transport equation. Within the relaxation time approximation, it is demonstrated that the electrical conductivity (σ) and Seebeck coefficient (S) of np-Si remain unchanged from the strain-free values under biaxial or shear strain. However, orthorhombic strain increases σ and S by as large as 68% and 110% compared to the unstrained structure, respectively, which is found to originate from the broken planar symmetry induced by the applied strain. Combined with the thermal conductivity, the improvement in σ and S of orthorhombically strained np-Si can enhance the maximum value of the thermoelectric figure of merit to as high as 0.8, which makes strain engineering particularly attractive for high-performance thermoelectrics.

11.
Nanoscale Adv ; 6(11): 2919-2927, 2024 May 29.
Artículo en Inglés | MEDLINE | ID: mdl-38817424

RESUMEN

Phonon transport in two-dimensional materials has been the subject of intensive studies both theoretically and experimentally. Recently observed unique phenomena such as Poiseuille flow at low temperature in graphene nanoribbons (GNRs) initiated strong interest in similar effects at higher temperatures. Here, we carry out massive molecular dynamics simulations to examine thermal transport in GNRs at room temperature (RT) and demonstrate that non-diffusive behaviors including Poiseuille-like local thermal conductivity and second sound are obtained, indicating quasiballistic thermal transport. For narrow GNRs, a Poiseuille-like thermal conductivity profile develops across the nanoribbon width, and wider GNRs exhibit a mixed nature of phonon transport in that diffusive transport is dominant in the middle region whereas non-uniform behavior is observed near lateral GNR boundaries. In addition, transient heating simulations reveal that the driftless second sound can propagate through GNRs regardless of the GNR width. By decomposing the atomic motion into out-of-plane and in-plane modes, it is further shown that the observed quasiballistic thermal transport is primarily contributed by the out-of-plane motion of C atoms in GNRs.

12.
Phys Rev Lett ; 110(19): 196802, 2013 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-23705733

RESUMEN

Although the stoichiometry of bulk lead sulfide (PbS) is exactly 1:1, that of quantum dots (QDs) can be considerably different from this crystalline limit. Employing first-principles calculations, we show that the impact of PbS QD stoichiometry on the electronic structure can be enormous, suggesting that control over the overall stoichiometry in the QD will play a critical role for improving the efficiency of optoelectronic devices made with PbS QDs. In particular, for bare PbS QDs, we find that: (i) stoichiometric PbS QDs are free from midgap states even without ligand passivation and independent of shape, (ii) off stoichiometry in PbS QDs introduces new states in the gap that are highly localized on certain surface atoms, and (iii) further deviations in stoichiometry lead to QDs with "metallic" behavior, with a dense number of energy states near the Fermi level. We further demonstrate that this framework holds for the case of passivated QDs by considering the attachment of ligand molecules as stoichiometry variations. Our calculations show that an optimal number of ligands makes the QD stoichiometric and heals unfavorable electronic structure, whereas too few or too many ligands cause effective off stoichiometry, resulting in QDs with defect states in the gap.

13.
Nanoscale ; 14(8): 3004-3012, 2022 Feb 24.
Artículo en Inglés | MEDLINE | ID: mdl-35170602

RESUMEN

Low- or self-powered infrared sensors can be used in a broad range of applications, including networking mobile edge devices and image recognition for autonomous driving technology. Here, we show state-of-the-art self-powered near-infrared (NIR) sensors using graphene/In/InSe/Au as a photoactive region. The self-powered NIR sensors show outstanding performance, achieving a photoresponsivity of ∼8.5 A W-1 and a detectivity of ∼1012 Jones at 850 nm light. Multiple self-powered InSe photodetectors with different device structures and contacts were systematically investigated. In particular, the asymmetrically assembled graphene/In/InSe/Au vertical heterostructure offers a high built-in field, which gives rise to efficient electron-hole pair separation and transit time that is shorter than the photocarrier lifetime. The built-in potential across the InSe was estimated using the Schottky barrier height at each metal contact with InSe, obtained using density functional theory calculations. We also demonstrate InSe vertical field-effect transistors and provide an out-of-plane carrier mobility of InSe. Using the out-of-plane mobility and structural parameters of each device, the built-in field, drift velocity, and corresponding transit time are estimated.

14.
Anal Biochem ; 412(1): 79-84, 2011 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-21262192

RESUMEN

Short tandem repeat (STR) loci are routinely analyzed by capillary electrophoresis. However, this method has several disadvantages, including long operational time, low throughput, and inaccuracy. As a result of the introduction of matrix-associated laser desorption/ionization time-of-flight (MALDI-TOF) and electrospray ionization (ESI), mass spectrometry has become an alternative method for genotyping polymorphic STR loci. Here we established a restriction fragment mass polymorphism (RFMP) assay for genotyping STR locus, TPOX, by typeIIS restriction endonuclease cleavage of polymerase chain reaction (PCR) amplicon followed by MALDI-TOF mass spectrometry. The resulting TPOX genotypes from this assay were in good agreement with the results from direct DNA sequencing and GeneScan assays. Our results showed that the RFMP assay is an accurate and high-throughput method for analyzing long DNA fragments such as STR markers. Further research with multiple STR loci may allow this assay to be used for diverse applications such as forensics, paternity tests, and detection of genetic disorders.


Asunto(s)
Yoduro Peroxidasa/genética , Repeticiones de Microsatélite , Polimorfismo de Longitud del Fragmento de Restricción , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción/métodos , Alelos , Sitios Genéticos , Genotipo , Humanos
15.
ACS Appl Mater Interfaces ; 13(40): 47749-47755, 2021 Oct 13.
Artículo en Inglés | MEDLINE | ID: mdl-34582182

RESUMEN

The natural abundance of magnesium together with its high volumetric energy capacity and less-dendritic anodes makes Mg-ion batteries an appealing alternative to the widely used Li-ion batteries. However, Mg cathode materials under current investigation suffer from various shortcomings such as low operation voltage and high energy barrier for ion migration, resulting in poor battery performance. Here, we propose a garnet-type intercalation cathode active material, Mg3Si3(MoO6)2, for high-performance Mg-ion batteries. Through first-principles density functional theory calculations, it is demonstrated that Mg3Si3(MoO6)2 possesses a high average discharge voltage (2.35 V vs Mg/Mg2+), a low ion migration barrier (∼0.2 eV), and a minimal volume change (∼4%) concurrently, which comprises excellent intercalation cathode chemistry. The small energy barrier for ion migration is shown to arise from the favorable change in the Mg coordination along the migration route within the garnet host. These findings present an additional direction to develop competent Mg-ion batteries for future energy storage applications.

16.
ACS Appl Mater Interfaces ; 13(1): 531-540, 2021 Jan 13.
Artículo en Inglés | MEDLINE | ID: mdl-33390000

RESUMEN

The influence of N-substituent and pKa of azole rings has been investigated for the performance of high-temperature polymer electrolyte membrane fuel cells (HT-PEMFCs). Imidazole, benzimidazole, and triazole groups were functionalized on the side chains of poly(phenylene oxide), respectively. Each azole group is categorized by their N-substituent into two types: unsubstituted and methyl-substituted azoles. The membranes with methyl-substituted azoles showed higher phosphoric acid (PA) doping levels with an average increase of 20% compared to those with unsubstituted azoles in the full-doped states. However, unsubstituted azoles more effectively improved the proton conductivity and the membrane with unsubstituted imidazole (IMPPO-H) showed a high anhydrous proton conductivity of 153 mS/cm at 150 °C. In contrast, the membranes with methyl-substituted azoles showed a higher PA retention with an average increase of 81% compared to those with unsubstituted azoles. The higher PA retention of methyl-substituted azoles also led to the higher fuel cell performance with the maximum increase of 95% in the power density. It was also revealed that higher pKa of azoles enhanced the PA retention and the fuel cell performance. Based on the experimental results of PA retention and density functional theory calculations, the PA loss mechanism was also proposed.

17.
Phys Rev Lett ; 104(1): 016602, 2010 Jan 08.
Artículo en Inglés | MEDLINE | ID: mdl-20366377

RESUMEN

We investigate the effect of O impurities on the thermoelectric properties of ZnSe from a combination of first-principles and analytic calculations. It is demonstrated that dilute amounts of O impurities introduce peaks in the density of states (DOS) above the conduction band minimum, and that the charge density near the DOS peaks is substantially attracted toward O atoms due to their high electronegativity. The impurity-induced peaks in the DOS result in a sharp increase of the room-temperature Seebeck coefficient and power factor from those of O-free ZnSe by a factor of 30 and 180, respectively. Furthermore, this effect is found to be absent when the impurity electronegativity well matches the host that it substitutes. The results suggest that highly electronegativity-mismatched alloys can be designed for high performance thermoelectric applications.

18.
Cancer Res ; 80(8): 1615-1623, 2020 04 15.
Artículo en Inglés | MEDLINE | ID: mdl-32066566

RESUMEN

Therapeutic interventions to harness the immune system against tumor cells have provided mixed results in the past for several solid tumors and hematologic malignancies. However, immunotherapy has advanced considerably over the last decade and is becoming an integral combination for treating patients with advanced solid tumors. In particular, prostate cancer immunotherapy has shown modest efficacy for patients in the past. With several key discoveries on immune mechanisms and advanced molecular diagnostic platforms recently, immunotherapy is re-emerging as a viable option for prostate cancer, especially castration-resistant prostate cancer (CRPC), to stimulate antitumor immunity. Combination of patient-tailored immunotherapy and immune checkpoint blockers with conventional cytotoxic agents and androgen receptor-targeted therapies should move the field forward. With a recent adaptation that the application of immune checkpoint inhibitors has been successful in the treatment of more than a dozen solid tumors, including melanoma, lymphoma, liver, cervical, gastrointestinal, and breast cancers, it is a timely endeavor to harness immunotherapy for prostate cancer. Here, we provide an account on the progression of immunotherapy with new discoveries and precision approaches for tumors, in particular CRPC, from mechanistic standpoint to emerging limitations and future directions.


Asunto(s)
Inmunoterapia/métodos , Neoplasias de la Próstata/terapia , Antagonistas de Receptores Androgénicos/uso terapéutico , Anticuerpos Biespecíficos/uso terapéutico , Antineoplásicos/uso terapéutico , Antígeno B7-H1/antagonistas & inhibidores , Antígeno CTLA-4/antagonistas & inhibidores , Terapia Combinada/métodos , Predicción , Humanos , Inmunización Pasiva/métodos , Inmunoterapia/tendencias , Inmunoterapia Activa/métodos , Masculino , Células Madre Neoplásicas/inmunología , Medicina de Precisión/métodos , Receptor de Muerte Celular Programada 1/antagonistas & inhibidores , Neoplasias de la Próstata/etiología , Neoplasias de la Próstata/inmunología , Neoplasias de la Próstata Resistentes a la Castración/inmunología , Neoplasias de la Próstata Resistentes a la Castración/terapia , Prostatitis/complicaciones
19.
ACS Appl Mater Interfaces ; 12(3): 4129-4134, 2020 Jan 22.
Artículo en Inglés | MEDLINE | ID: mdl-31880145

RESUMEN

Contact engineering for two-dimensional (2D) transition metal dichalcogenides (TMDCs) is crucial for realizing high-performance 2D TMDC devices, and most studies on contact properties of 2D TMDCs have mainly focused on Fermi level unpinning. Here, we investigated electrical and photoelectrical properties of chemical vapor deposition (CVD)-grown molybdenum disulfide (MoS2) monolayer devices depending on metal contacts, Ti/Pt, Ti/Au, Ti, and Ag, and particularly demonstrated the essential role of defects in MoS2 in contact properties. Remarkably, MoS2 devices with Ag contacts show a field-effect mobility of 12.2 cm2 V-1 s-1, an on/off current ratio of 7 × 107, and a photoresponsivity of 1020 A W-1, which are outstanding compared to similar devices with other metal contacts. These improvements are attributed to a reduced Schottky barrier height, thanks to the small work function of Ag and Ag-MoS2 orbital hybridization at the interface, which facilitates efficient charge transfer between MoS2 and Ag. Interestingly, X-ray photoelectron spectroscopic analysis reveals that Ag2S was formed in our defect-containing CVD-grown MoS2 monolayer, but such orbital hybridization is not observed in a nearly defect-free exfoliated MoS2. This distinction shows that defects existing in MoS2 enable Ag to effectively couple to MoS2 and correspondingly enhance multiple electrical and photoelectrical properties.

20.
Mol Cancer Ther ; 19(12): 2585-2597, 2020 12.
Artículo en Inglés | MEDLINE | ID: mdl-33199500

RESUMEN

Complexities in treating breast cancer with bone metastasis are enhanced by a vicious protumorigenic pathology, involving a shift in skeletal homeostasis toward aggressive osteoclast activity and polarization of immune cells supporting tumor growth and immunosuppression. Recent studies signify the role of receptor activator of NF-κB ligand (RANKL) beyond skeletal pathology in breast cancer, including tumor growth and immunosuppression. By using an osteoprotegerin (OPG) variant, which we developed recently through protein engineering to uncouple TNF-related apoptosis-inducing ligand (TRAIL) binding, this study established the potential of a cell-based OPGY49R therapy for both bone damage and immunosuppression in an immunocompetent mouse model of orthotopic and metastatic breast cancers. In combination with agonistic death receptor (DR5) activation, the OPGY49R therapy significantly increased both bone remolding and long-term antitumor immunity, protecting mice from breast cancer relapse and osteolytic pathology. With limitations, cost, and toxicity issues associated with the use of denosumab, bisphosphonates, and chemotherapy for bone metastatic disease, use of OPGY49R combination could offer a viable alternate therapeutic approach.


Asunto(s)
Remodelación Ósea/efectos de los fármacos , Remodelación Ósea/genética , Neoplasias/inmunología , Neoplasias/metabolismo , Osteoprotegerina/genética , Ligando Inductor de Apoptosis Relacionado con TNF/antagonistas & inhibidores , Ligando Inductor de Apoptosis Relacionado con TNF/metabolismo , Animales , Antineoplásicos Inmunológicos/farmacología , Neoplasias Óseas/diagnóstico por imagen , Neoplasias Óseas/metabolismo , Neoplasias Óseas/secundario , Línea Celular Tumoral , Citocinas , Modelos Animales de Enfermedad , Femenino , Humanos , Inmunohistoquímica , Macrófagos/efectos de los fármacos , Macrófagos/inmunología , Macrófagos/metabolismo , Ratones , Neoplasias/tratamiento farmacológico , Neoplasias/patología , Osteoprotegerina/metabolismo , Unión Proteica , Receptor Activador del Factor Nuclear kappa-B/metabolismo , Linfocitos T/efectos de los fármacos , Linfocitos T/inmunología , Linfocitos T/metabolismo , Microtomografía por Rayos X
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA