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1.
Acc Chem Res ; 55(3): 429-441, 2022 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-35044167

RESUMO

ConspectusTransparent conducting oxides (TCOs) are inorganic electrical conductors with optical band gaps greater than 3.3 eV. TCOs have been extensively explored in functional windows, touch screen applications, transparent displays, solar cells, and even electronic circuits. Amorphous metal oxide (a-MO) semiconductors are a TCO class that has made impressive progress since the first 2004 demonstration of their utility as the semiconducting layer in thin-film transistors (TFTs). Their excellent counterintuitive electron mobilities in the amorphous state fill the performance gap between amorphous silicon and polysilicon, widening TFT applicability to high-value products such as high-resolution flat panel displays and emerging flexible/wearable electronics. The possibility of solution processing MO "inks" from air-stable precursors, via roll-to-roll and high-throughput printing, further expands their appeal. However, most MO TFTs fabricated using solution-processing require postdeposition film annealing at elevated temperatures (>400 °C) to ensure high-quality films and stable charge transport. Thus, MO fabrication on and TFT integration with inexpensive and typically temperature-sensitive flexible polymer substrates remains challenging, as does reducing MO processing times to those acceptable for high-throughput semiconductor circuit manufacture. Consequently, new MO film processing methodologies are being developed to meet these requirements. Among them, science-based combustion synthesis (CS) and polymer doping are promising complementary approaches to optimize materials quality and manufacturing efficiency; they are the topic of this Account.This Account summarizes the progress in CS and MO polymer doping research, made largely at Northwestern University over the past decade, to create high-performance MO TFTs. Regarding CS, we begin with an overview of combustion precursor chemistry that strongly affects the resulting film quality and device performance. Then, single fuel and dual fuel combustion syntheses for diverse MO systems are discussed. Representative examples highlight recent advances, with a focus on the relationship between (co)fuel-oxidizer types/amounts, thermal behavior, film microstructure, and TFT performance. Next, the discussion focuses on polymer doping of several MO matrices as a new approach to achieve semiconducting MO compositions with excellent performance and mechanical flexibility. Thus, the effect of the polymer architecture and content in the MO precursor formulations on the MO film composition, microstructure, electronic structure, and charge transport are discussed. The concluding remarks highlight challenges and emerging opportunities.

2.
Emerg Infect Dis ; 25(10): 1861-1867, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31538558

RESUMO

Carbapenem-resistant Pseudomonas aeruginosa (CRPA) is a public health concern worldwide, but comprehensive analysis of risk factors for CRPA remains limited in China. We conducted a retrospective observational study of carbapenem resistance in 71,880 P. aeruginosa isolates collected in Zhejiang Province during 2015-2017. We analyzed risk factors for CRPA, including the type of clinical specimen; the year, season, and region in which it was collected; patient information, including age, whether they were an outpatient or inpatient, and whether inpatients were in the intensive care unit or general ward; and the level of hospital submitting isolates. We found CRPA was more prevalent among isolates from patients >60 years of age and in inpatients, especially in intensive care units. In addition, specimen types and seasons in which they were collected were associated with higher rates of CRPA. Our findings can help hospitals reduce the spread of P. aeruginosa and optimize antimicrobial drug use.


Assuntos
Carbapenêmicos/uso terapêutico , Infecção Hospitalar/etiologia , Infecções por Pseudomonas/etiologia , Adolescente , Adulto , Fatores Etários , Criança , Pré-Escolar , China/epidemiologia , Infecção Hospitalar/tratamento farmacológico , Infecção Hospitalar/microbiologia , Humanos , Lactente , Recém-Nascido , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Infecções por Pseudomonas/tratamento farmacológico , Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa/efeitos dos fármacos , Estudos Retrospectivos , Fatores de Risco , Adulto Jovem , Resistência beta-Lactâmica
3.
Inorg Chem ; 53(13): 6585-95, 2014 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-24914731

RESUMO

Lithium iron borate (LiFeBO3) has a high theoretical specific capacity (220 mAh/g), which is competitive with leading cathode candidates for next-generation lithium-ion batteries. However, a major factor making it difficult to fully access this capacity is a competing oxidative process that leads to degradation of the LiFeBO3 structure. The pristine, delithiated, and degraded phases of LiFeBO3 share a common framework with a cell volume that varies by less than 2%, making it difficult to resolve the nature of the delithiation and degradation mechanisms by conventional X-ray powder diffraction studies. A comprehensive study of the structural evolution of LiFeBO3 during (de)lithiation and degradation was therefore carried out using a wide array of bulk and local structural characterization techniques, both in situ and ex situ, with complementary electrochemical studies. Delithiation of LiFeBO3 starts with the production of LitFeBO3 (t ≈ 0.5) through a two-phase reaction, and the subsequent delithiation of this phase to form Lit-xFeBO3 (x < 0.5). However, the large overpotential needed to drive the initial two-phase delithiation reaction results in the simultaneous observation of further delithiated solid-solution products of Lit-xFeBO3 under normal conditions of electrochemical cycling. The degradation of LiFeBO3 also results in oxidation to produce a Li-deficient phase D-LidFeBO3 (d ≈ 0.5, based on the observed Fe valence of ∼2.5+). However, it is shown through synchrotron X-ray diffraction, neutron diffraction, and high-resolution transmission electron microscopy studies that the degradation process results in an irreversible disordering of Fe onto the Li site, resulting in the formation of a distinct degraded phase, which cannot be electrochemically converted back to LiFeBO3 at room temperature. The Li-containing degraded phase cannot be fully delithiated, but it can reversibly cycle Li (D-Lid+yFeBO3) at a thermodynamic potential of ∼1.8 V that is substantially reduced relative to the pristine phase (∼2.8 V).

4.
Antimicrob Agents Chemother ; 56(5): 2278-82, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22354308

RESUMO

Nineteen carbapenem-nonsusceptible Proteus mirabilis isolates were recovered from intensive care units in the Second Affiliated Hospital of Zhejiang University during a 3-month period. The isolates showed a high level of resistance against ciprofloxacin, in addition to their resistance against the carbapenems. Pulsed-field gel electrophoresis (PFGE) analysis showed that these isolates belonged to three clonal strains. PCRs and DNA sequence analysis of the carbapenemase and other ß-lactamase genes indicated that all the isolates harbored the bla(KPC-2) gene. Twelve of 19 isolates harbored the plasmid-mediated quinolone resistance (PMQR) genes, both the qnrD and aac(6')-Ib-cr genes. Eight representative isolates with high levels of quinolone resistance carried the similar mutation profiles of S83I in gyrA, E466D in gyrB, and S80I in parC. Reduced carbapenem susceptibility was transferred to Escherichia coli (EC600) in a conjugation experiment, while the quinolone resistance was not. DNA hybridization showed that qnrD was located on a plasmid of approximately 4.5 kb. In summary, large clonally related isolates of KPC-2-producing P. mirabilis emerged in a Chinese hospital, and qnrD was detected in KPC-producing P. mirabilis for the first time.


Assuntos
Antibacterianos/uso terapêutico , Infecção Hospitalar/tratamento farmacológico , Farmacorresistência Bacteriana Múltipla/genética , Genes Bacterianos , Infecções por Proteus/tratamento farmacológico , Proteus mirabilis/genética , Antibacterianos/administração & dosagem , Proteínas de Bactérias/genética , Carbapenêmicos/administração & dosagem , Carbapenêmicos/uso terapêutico , China , Ciprofloxacina/administração & dosagem , Ciprofloxacina/uso terapêutico , Células Clonais , Conjugação Genética , Infecção Hospitalar/microbiologia , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Eletroforese em Gel de Campo Pulsado , Escherichia coli/genética , Genes Bacterianos/efeitos dos fármacos , Humanos , Plasmídeos/genética , Reação em Cadeia da Polimerase , Infecções por Proteus/microbiologia , Proteus mirabilis/isolamento & purificação , Quinolonas/administração & dosagem , Quinolonas/uso terapêutico , Análise de Sequência de DNA , beta-Lactamases/genética
5.
World J Gastroenterol ; 11(16): 2426-30, 2005 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-15832412

RESUMO

AIM: To evaluate the anti-tumor effects and possible involvement of anti-tumor immunity of electrochemotherapy (ECT) employing electroporation and bleomycin in human colon cancer xenografts in nude mice, and to establish the experimental basis for clinical application of ECT. METHODS: Forty nude mice, inoculated subcutaneously human colon cancer cell line LoVo for 3 wk, were allocated randomly into four groups: B+E+ (ECT), B+E- (administration of bleomycin alone), B-E+ (administration of electric pulses alone), and B-E- (no treatment). Tumor volumes were measured daily. The animals were killed on the 7th d, the weights of xenografts were measured, and histologies of tumors were evaluated. Cytotoxicity of spleen natural killer (NK) and lymphokine-activated killer (LAK) cells was then assessed by lactic dehydrogenase release assay. RESULTS: The mean tumor volume of group B+E+ was statistically different from the other three groups after the treatment (F = 36.80, P<0.01). There was one case of complete response, seven cases of partial response (PR) in group B+E+, one case of PR in group B+E- and group B-E+ respectively, and no response was observed in group B-E-. The difference of response between group B+E+ and the other three groups was statistically significant (chi2 = 25.67, P<0.01). Histologically, extensive necrosis of tumor cells with considerable vascular damage and inflammatory cells infiltration were observed in group B+E+. There was no statistical difference between the cytotoxicity of NK and LAK cells in the four treatment groups. CONCLUSION: ECT significantly enhances the chemosensitivity and effects of chemotherapy in human colon cancer xenografts in nude mice, and could be a kind of novel treatment modality for human colon cancer. The generation of T-cell-dependent, tumor-specific immunity might be involved in the process of ECT.


Assuntos
Antibióticos Antineoplásicos/farmacologia , Bleomicina/farmacologia , Neoplasias do Colo/tratamento farmacológico , Terapia por Estimulação Elétrica/métodos , Eletroporação/métodos , Animais , Linhagem Celular Tumoral , Neoplasias do Colo/imunologia , Neoplasias do Colo/patologia , Humanos , Células Matadoras Naturais/imunologia , Ativação Linfocitária , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Ensaios Antitumorais Modelo de Xenoenxerto
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