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1.
J Phys Chem Lett ; 15(9): 2550-2556, 2024 Mar 07.
Artículo en Inglés | MEDLINE | ID: mdl-38416028

RESUMEN

Chiral plasmonic nanostructures can produce strong chiral optical responses and have potential applications in photonics. Experimentally, metallic nanoparticle helices have been synthesized to achieve strong chiral responses. Strong coupling effects between the quantum emitters and the plasmon have attracted significant attention in the past decade and have been recently extended to the chiral plasmon of nanostructures. However, the strong coupling between molecules and metallic nanosphere helices has not been reported yet. In this article we study theoretically such an effect and examine the modulation of chiral and coupling effects by illumination light and molecular layer thickness. Our study may guide further experimental studies.

2.
Phys Chem Chem Phys ; 25(35): 23548-23554, 2023 Sep 13.
Artículo en Inglés | MEDLINE | ID: mdl-37650210

RESUMEN

3,4,9,10-Perylenetetracarboxylic-dianhydride (PTCDA) aggregates have unique optical properties and are model materials for studying exciton energy transfer (EET) in planar stacked molecular aggregates. In the framework of density matrix theory, a hierarchy of molecular transition operator expectation values could be constructed to derive the equations of motion of multi-exciton states. Realistic parameters for PTCDA molecules are used to study EET and the optical response of two-dimensional aggregates upon local excitation. Our simulations show that information about the dark state can be obtained with local field excitation and the inter-chain coupling results in a red-shift of the lowest excitonic energy level. Configuration effects, inter-chain detuning and multi-exciton states are discussed. The calculated lowest excitonic energy level of a 2D PTCDA aggregate is qualitatively consistent with the lowest experimental absorption peak of a PTCDA film. The obtained results are valuable for the study of aggregates in optical nanocavities and for the design of photoelectric devices.

3.
Environ Sci Technol ; 57(19): 7410-7420, 2023 05 16.
Artículo en Inglés | MEDLINE | ID: mdl-37134202

RESUMEN

Hot springs represent a major source of arsenic release into the environment. Speciation is typically reported to be dominated by arsenite, arsenate, and inorganic thiolated arsenates. Much less is known about the relevance and formation of methylated thioarsenates, a group with species of high mobility and toxicity. In hot spring samples taken from the Tengchong volcanic region in China, methylated thioarsenates contributed up to 13% to total arsenic. Enrichment cultures were obtained from the corresponding sediment samples and incubated to assess their capability to convert arsenite into methylated thioarsenates over time and in the presence of different microbial inhibitors. In contrast to observations in other environmental systems (e.g., paddy soils), there was no solid evidence, supporting that the sulfate-reducing bacteria contributed to the arsenic methylation. Methanosarcina, the sole genus of methanogens detected in the enrichment cultures, as well as Methanosarcina thermophila TM-1, a pure strain within the genus, did methylate arsenic. We propose that methylated thioarsenates in a typical sulfide-rich hot spring environment like Tengchong form via a combination of biotic arsenic methylation driven by thermophilic methanogens and arsenic thiolation with either geogenic sulfide or sulfide produced by sulfate-reducing bacteria.


Asunto(s)
Arsénico , Arsenitos , Manantiales de Aguas Termales , Manantiales de Aguas Termales/microbiología , Metilación , Sulfuros , Sulfatos
4.
Front Microbiol ; 14: 1295363, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-38287960

RESUMEN

Background: The burden of cryptococcosis in mainland China is enormous. However, the in vitro characterization and molecular epidemiology in Guangdong, a key region with a high incidence of fungal infection in China, are not clear. Methods: From January 1, 2010, to March 31, 2019, clinical strains of Cryptococcus were collected from six medical centres in Guangdong. The clinical information and characteristics of the strains were analysed. Furthermore, molecular types were determined. Results: A total of 84 strains were collected, mostly from male and young or middle-aged adult patients. Pulmonary and cerebral infections (82.1%) were most common. All strains were Cryptococcus neoformans, grew well at 37°C and had capsules around their cells. One melanin- and urea- and one melanin+ and urea- variants were found. Although most strains exhibited a low minimum inhibitory concentration (MIC) value for voriconazole (mean: 0.04 µg/mL) and posaconazole (mean: 0.12 µg/mL), the results for these isolates showed a high degree of variation in the MIC values of fluconazole and 5-fluorocytosine, and resistance was observed for 4 out of 6 drugs. A significant proportion of these strains had MIC values near the ECV values, particularly in the case of amphotericin B. The proportion of strains near the clinical breakpoints was as follows: fluconazole: 3.66%; voriconazole: 3.66%; itraconazole: 6.10%; posaconazole: 13.41%; amphotericin B: 84.15%; 5-fluorocytosine: 2.44%. These strains were highly homogeneous and were dominated by the Grubii variant (95.2%), VNI (94.0%), α mating (100%), and ST5 (89.3%) genotypes. Other rare types, including ST4, 31, 278, 7, 57 and 106, were also found. Conclusion: Phenotypically variant and non-wild-type strains were found in Guangdong, and a significant proportion of these strains had MIC values near the ECV values towards the 6 antifungal drugs, and resistance was observed for 4 out of 6 drugs. The molecular type was highly homogeneous but compositionally diverse, with rare types found. Enhanced surveillance of the aetiology and evolution and continuous monitoring of antifungal susceptibility are needed to provide references for decision-making in the health sector and optimization of disease prevention and control.

5.
Medicine (Baltimore) ; 101(46): e31911, 2022 Nov 18.
Artículo en Inglés | MEDLINE | ID: mdl-36401434

RESUMEN

Adjuvant endocrine therapy (AET) is known to reduce the risk of hormone receptor-positive (HR+) breast cancer (BC) recurrence and mortality rates, but its impact on cardiovascular disease (CVD) events is unclear. The primary objective of this study was to analyze the association of HR status with CVD mortality in patients with stage I to III BC. A retrospective study of patients with stage I to III BC was conducted using the 2004 to 2016 Surveillance, Epidemiology, and End Results (SEER) database, and patients were grouped according to their HR status. Propensity score matching (PSM) was used to adjust for heterogeneity between the groups. The cumulative incidence rate of CVD mortality was evaluated via a cumulative incidence curve. Univariate and multivariate Fine and Gray's competing risk regression models were used to identify risk factors associated with CVD mortality. In total, 399,209 patients with BC were included in this study, and 329,958 patients (82.65%) were HR-positive. The cumulative incidence of CVD death was 8.28% in stage I to III BC patients. In the constituent ratio analysis, primary BC was the leading cause of death (45.29%, N = 31,465), followed by heart disease (16.07%, N = 11,166). Compared to the second year following BC diagnosis, the risk of CVD-specific death gradually increased. After PSM, 65,952 pairs of patients were matched, which led to the equilibrium of all variables between the HR-negative cohort and HR+ cohort. Multivariate analysis indicated that HR status was not significantly associated with the risk of CVD mortality, with a hazard ratio of 1.01 (P = .895). This study highlights the importance of understanding the associations between risk factors and CVD for BC patients. HR status was not associated with the risk of CVD mortality in this study.


Asunto(s)
Neoplasias de la Mama , Enfermedades Cardiovasculares , Humanos , Femenino , Estudios Retrospectivos , Recurrencia Local de Neoplasia/complicaciones , Hormonas
6.
Front Endocrinol (Lausanne) ; 13: 1014558, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36213273

RESUMEN

Objective: This study aimed to examine the efficacy of HRT with gonadotropin-releasing hormone agonist (GnRH-a) pre-treatment in women with male-factor infertility who underwent a frozen embryo transfer (FET) programme. Design: Between January 2016 and October 2020, 2733 women with male-factor infertility who underwent the HRT protocol as the endometrial preparation method were enrolled at two Reproductive Medicine Centres. Patients were divided into two groups based on whether they had GnRH-a pre-treatment before HRTs: the GnRHa-HRT group and the HRT group. The inverse probability of treatment weighting (IPTW) method was conducted to balance patient baseline characteristics between treatment cohorts to reduce selection bias. The live birth rate was considered regarded as the primary pregnancy outcome. Results: Multivariate logistic regression adjusted for confounding factors, the GnRHa-HRT group showed a notably higher rate of live birth (OR 2.154, 95% CI 1.636~2.835, P<0.001) when compared to the HRT group. Additionally, the rate of miscarriage was significantly lower in the GnRHa-HRT group. The GnRHa-HRT group had significantly higher rates of biochemical pregnancy, clinical pregnancy, multiple pregnancy, and term birth. Conclusion: The endometrial preparation protocol of HRT with GnRH-a pre-treatment could obviously increase the live birth rate for women with male-factor infertility undergoing the FET programme.


Asunto(s)
Infertilidad , Resultado del Embarazo , Transferencia de Embrión/métodos , Femenino , Hormona Liberadora de Gonadotropina , Terapia de Reemplazo de Hormonas , Humanos , Masculino , Embarazo
7.
Cell Mol Biol (Noisy-le-grand) ; 67(6): 68-73, 2022 Feb 27.
Artículo en Inglés | MEDLINE | ID: mdl-35818212

RESUMEN

Prostate cancer is a common clinical disease in men. It is known that prostate cancer ranks 3rd in the incidence of malignant tumors of the male genitourinary system in China, which is able to evaluate the riskiness of life expectancy of male patients. Therefore, we investigated the expression of CD133, recombinant human kallikrein 3 (Klk3), grainy head like 2 (grhl2) in prostate cancer, and correlation with tumor characteristics in the present study. A total of 167 prostate cancer patients who underwent surgical treatment in our hospital from February 2017 to April 2021 were selected. Their cancer and adjacent tissues were resected, and CD133 was detected by double staining using immunohistochemistry, Klk3 and grhl2 were detected by RT-PCR analysis, and CD133, Klk3 were analyzed by Pearson's method in different clinical stages, Gleason grade Correlation of grhl2 with tumor characteristics. The expression of CD133, KLK3, and GRHL2 in cancer tissue was increased compared with adjacent tissue (P < 0.05). The expression of CD133, KLK3, and GRHL2 increased with the aggravation of the clinical stage and Gleason grade (P < 0.05). CD133, KLK3, and GRHL2 showed a positive correlation in prostate cancer. The Pearson method found a positive correlation between CD133, KLK3, GRHL2 and clinical stage, Gleason grade, and lymph node metastasis. In general, high CD133, Klk3, and grhl2 expression was observed in prostate cancer and increased with the disease. They presented a positive correlation in prostate cancer presence, and these three gene products correlated with tumor characteristics.


Asunto(s)
Antígeno AC133 , Proteínas de Unión al ADN , Calicreínas , Antígeno Prostático Específico , Neoplasias de la Próstata , Factores de Transcripción , Antígeno AC133/genética , China , Proteínas de Unión al ADN/genética , Humanos , Inmunohistoquímica , Calicreínas/genética , Masculino , Clasificación del Tumor , Antígeno Prostático Específico/genética , Neoplasias de la Próstata/genética , Neoplasias de la Próstata/patología , Factores de Transcripción/genética
8.
Sci Total Environ ; 827: 154016, 2022 Jun 25.
Artículo en Inglés | MEDLINE | ID: mdl-35271921

RESUMEN

Arsenic (As) from deep crust is transported by geothermal waters to the earth surface and retained by sediment through adsorption, which depends significantly on the occurring As species. Adsorption of oxyarsenic species (i.e. arsenite [iAs(III)] and arsenate [iAs(V)]) on pure minerals was intensively investigated, yet studies with natural sediments and less known As species are scarce. To fill this gap, we investigated adsorption kinetics of nine different As species onto three typical geothermal sediments with different sedimentary organic matter (SOM) and iron (Fe) levels under anaerobic, sulfidic conditions (pH = 6). A multispecies pseudo-second-order (MPSO) model was applied to extract the adsorption rates of individual As species. Results showed that only the sediment with both high SOM and high Fe exhibited considerable As adsorption capacity. Air exposure or rise of either SOM or Fe levels in sediment favoured de-thiolation of aqueous thioarsenates, except for dimethylated thioarsenates. The overall adsorbed amount of the spiked As was affected by concurrent (de-)thiolation of the initial species, and the rates of their adsorption to the high SOM and high Fe sediment decreased in the order of tetrathioarsenate (TetraTA) > monothioarsenate (MTA) > iAs(V) > monomethyl arsenate (MMA) > dimethyl arsenate (DMA) > iAs(III) > monomethyl monothioarsenate (MMMTA) > dimethyl monothioarsenate (DMMTA) > dimethyl dithioarsenate (DMDTA). The fastest and slowest adsorption were suggested for inorganic thioarsenates and methylated thioarsenates, respectively. Therefore, under typical geothermal scenarios, thiolation of inorganic As would not necessarily increase its mobility, but the formation of methylated oxyarsenates and their further thiolation would endow geothermal As with strong migration ability.


Asunto(s)
Arsénico , Arsenicales , Arseniatos , Metilación , Sulfuros
9.
Phys Chem Chem Phys ; 24(5): 3289-3295, 2022 Feb 02.
Artículo en Inglés | MEDLINE | ID: mdl-35048933

RESUMEN

Constructed via in-plane heterojunction contacts between the semiconducting 2H phase (as the channel) and the metallic 1T' phase (as the electrode), two-dimensional (2D) transition metal dichalcogenide (TMD) field-effect transistors (FETs) have received much recent attention because they significantly reduce contact resistance. In this paper, ab initio quantum transport simulation is done to study and predict the electronic states and contact properties of the 2H-MoS2/1T'-MX2 (WS2, TaSe2, NbSe2, MoSe2, TaS2, and NbS2) in-plane heterojunctions. It is found that the interfacial states are not obvious and the fluctuation of the average electron density at the 1T'/2H phase boundary is small for all 2H-MoS2/1T'-MX2 heterojunctions. The average electrostatic potential differences (ΔV) are all negative, which is beneficial to promote the charge transfer from 1T'-MX2 to 2H-MoS2. Moreover, the p-type Schottky contact of the 2H-MoS2/1T'-MX2 heterojunctions is formed and the ΦSB,P values are 0.609 eV, 0.625 eV, 0.641 eV, 0.617 eV, 0.469 eV and 0.477 eV for 1T'-WS2, 1T'-TaSe2, 1T'-NbSe2, 1T'-MoSe2, 1T'-TaS2, and 1T'-NbS2, respectively. The results provide theoretical guidance for designing two-dimensional material devices.

10.
Phys Chem Chem Phys ; 23(45): 25769-25775, 2021 Nov 24.
Artículo en Inglés | MEDLINE | ID: mdl-34755738

RESUMEN

Excitonic energy transfer among the zinc chlorin molecules is significant for the photovoltaic process because of their high sensitivities to harvesting sunlight. Zinc chlorin monomers and dimers can be synthesized experimentally, and they can form various self-assembled structures. Using the realistic parameters of zinc chlorin molecules, we assume that 20 molecules with J-, H- or J-H aggregation are arranged in a line and we investigate their dipole configuration effect on exciton dynamics. The expectation value approximation of operators is applied to derive the equations of motion of multi-exciton states. The temporal evolution of multi-exciton states is analyzed in the scheme of density matrix theory. Our simulations show that the inter-molecular coupling results in an exciton band and the wave-packet progressing excited by the resonant laser pulse exhibits attractive or repulsive behavior at the exciton level due to the dipole configuration effect. In the defined J-H coupling, the coherent wave-packet cannot overcome the configuration barrier to the no-excited part. The exciton dynamics revealed here might be helpful to better understand the energy transfer process in organic photovoltaic devices.

11.
Artículo en Inglés | MEDLINE | ID: mdl-34831998

RESUMEN

With the acceleration of industrialization and urbanization, the Yangtze River Economic Belt (YREB) is facing many environmental problems that need to be solved in the process of development. This paper aims to analyze the environmental governance effects of nine provinces and two municipalities in the Yangtze River Economic Belt from 2009 to 2018. Firstly, based on the input-output index, the slacks-based measure (SBM) undesirable model and Malmquist (ML) index were used to measure the green total factor productivity (GTFP) of the YREB from 2009 to 2018. The results showed that the technological progress index contributed the most to the GTFP of the YREB, followed by the pure technical efficiency index and the scale efficiency index. Environmental regulation has no significant impact on the GTFP of the YREB. Secondly, by analyzing the effect of environmental governance in the YREB, the results show that the main reasons for the ineffective environmental governance in the YREB are the redundant input of environmental resources, excessive unwanted output, and low harmless treatment rate of municipal solid waste, rather than the low level of urban environmental management. Finally, this paper provides recommendations for the ineffective provinces and municipalities of the YREB to further optimize the input-output factors of environmental governance.


Asunto(s)
Desarrollo Económico , Ríos , China , Ciudades , Conservación de los Recursos Naturales , Política Ambiental
12.
Arch Pharm (Weinheim) ; 353(3): e1900294, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-31894862

RESUMEN

A series of (3-benzyl-5-hydroxyphenyl)carbamates were evaluated as new antibacterial agents. Several compounds showed potent inhibitory activity against sensitive and drug-resistant Gram-positive bacteria. The compounds are ineffective against all tested Gram-negative bacteria. The structure of the ester group exerted a profound effect on antibacterial activity. 4,4-Dimethylcyclohexanyl carbamate 6h exhibited the most potent inhibitory activity against the standard and clinically isolated Staphylococcus aureus, Staphylococcus epidermidis, and Enterococcus faecalis (minimum inhibitory concentration = 4-8 µg/ml) strains. The preliminary experimental evidence indicated that these carbamates target the bacterial cell wall and share a similar mechanism of action with vancomycin.


Asunto(s)
Antibacterianos/farmacología , Carbamatos/farmacología , Enterococcus faecalis/efectos de los fármacos , Staphylococcus aureus/efectos de los fármacos , Staphylococcus epidermidis/efectos de los fármacos , Antibacterianos/síntesis química , Antibacterianos/química , Carbamatos/síntesis química , Carbamatos/química , Ensayos de Selección de Medicamentos Antitumorales , Pruebas de Sensibilidad Microbiana , Estructura Molecular , Relación Estructura-Actividad
13.
Microb Drug Resist ; 26(2): 100-109, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31441704

RESUMEN

ZTW-41, an indolizinoquinoline-5,12-dione derivative, was investigated for antibacterial activity against Gram-positive bacteria, especially methicillin-resistant Staphylococcus aureus (MRSA). In our study, the MIC90s (minimum inhibitory concentrations) of ZTW-41 against MRSA (MRSA, n = 200), methicillin-sensitive S. aureus (MSSA, n = 100), Enterococcus faecalis (E. faecalis, n = 32), and Enterococcus faecium (E. faecium n = 32) were 0.25, 0.25, 0.125, and 8 µg/mL, respectively, whereas the MBC90s (minimum bactericidal concentrations) were 2, 1, 1, and >32 µg/mL, respectively. ZTW-41 maintained its potency at different pH levels (range 5-9) and in starting inoculum size up to 107 CFU/mL. The presence of human serum (25-75%) increased ZTW-41 MICs by two- to eightfold. Time-kill curves showed that ZTW-41 had bactericidal activity against MRSA, MSSA, and E. faecalis strains within 8 hours, and rebound growth occurred after 8 hours except at higher multiples of the MIC (4 × and 8 × ). In the acute toxicity study, no mortality or signs of toxicity was noted in mice after 14 days of observation at doses <50 mg/kg. ZTW-41 exhibited good selectivity indices (SIs) (SI = IC50/MIC90) ranging from 1.12 to 71.76 against clinical isolates, demonstrating excellent therapeutic selectivity in MRSA, MSSA, and E. faecalis strains. Moreover, the in vivo efficacy (effective dose [ED]50 = 6.59 mg/kg) of ZTW-41 was found comparable with vancomycin. Collectively, our favorable results supported ZTW-41 as a promising investigational candidate for treating drug-resistant bacteria infection.


Asunto(s)
Antibacterianos/farmacología , Enterococcus/efectos de los fármacos , Staphylococcus aureus/efectos de los fármacos , Animales , Relación Dosis-Respuesta a Droga , Farmacorresistencia Bacteriana Múltiple , Humanos , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Ratones , Pruebas de Sensibilidad Microbiana , Unión Proteica
14.
Clin Infect Dis ; 67(suppl_2): S179-S188, 2018 11 13.
Artículo en Inglés | MEDLINE | ID: mdl-30423046

RESUMEN

Background: The global dissemination of carbapenem-resistant Acinetobacter baumannii clonal complex (CC) 92 has become an urgent public health concern. Methods: A. baumannii isolates were collected in 5 tertiary hospitals in south China during 2012-2015, and their clinical data were obtained. The clinical characterization was studied by statistical analysis. Whole-genome sequencing and a Galleria mellonella infection model were used to investigate the genetic characterization and pathogenicity of isolates, respectively. Results: Sequence type (ST)457, following ST195, become the second-most prevalent clone in our collection. Patients infected by ST457 had significantly higher 7-day mortality rates (44.4% vs 14.3%; P = .01) and proportions of 7-day deaths (70.6% vs 26.7%; P = .01) than those infected by the other STs of CC92, except for ST195 and ST208. Consistently, the day of death after culture was significantly sooner in patients infected with ST457 than those with the non-ST195/208 members of CC92 (8.71 ± 15.27 vs 25.20 ± 6.51; P = .02). This is accordant with results that ST457 had enhanced virulence with a high mortality rate through use of the G. mellonella larvae infection model. Genomic analysis suggests that ST457 evolved distinctly from the other CC92 members mainly via recombinations. This clone exclusively shared a few virulence factors with the hypervirulence strain LAC-4, including a capsule biosynthesis locus (KL49) that is supposed to be important for the hypervirulence in LAC-4. Conclusions: The rising trends in prevalence and enhanced virulence of ST457 highlight the urgent need for tailored surveillance to control the further dissemination of this clone.


Asunto(s)
Infecciones por Acinetobacter/mortalidad , Acinetobacter baumannii/genética , Acinetobacter baumannii/patogenicidad , Enfermedades Endémicas , Factores de Virulencia/genética , Infecciones por Acinetobacter/microbiología , Anciano , Anciano de 80 o más Años , Animales , Técnicas de Tipificación Bacteriana , Carbapenémicos/farmacología , China/epidemiología , Evolución Molecular , Femenino , Genómica , Neumonía Asociada a la Atención Médica/epidemiología , Neumonía Asociada a la Atención Médica/microbiología , Humanos , Larva , Masculino , Persona de Mediana Edad , Mariposas Nocturnas , Tipificación de Secuencias Multilocus , Prevalencia , Virulencia , Secuenciación Completa del Genoma
15.
Sci Rep ; 7(1): 15279, 2017 11 10.
Artículo en Inglés | MEDLINE | ID: mdl-29127419

RESUMEN

Acinetobacter baumannii has been a dreadful problem for ICU physicians for a long time. Bacteremic pneumonia (BP) caused by this organism has a higher mortality compared to other organisms. Between 2012 and 2015, 86 BP and 89 non-bacteremic pneumonia (NBP) patients from five ICUs were enrolled into the study. The 7-day and 14-day mortality rates were higher in BP patients than in NBP patients (P < 0.001). Procalcitonin elevation, high APACHEII score and recent surgery, were independently associated with BP episodes. Acute respiratory distress syndrome, coma, high APACHEII score and procalcitonin elevation, were independently associated with mortality in the BP group. Extensively drug-resistant isolates were detected in 34.9% of BP and 25.8% of NBP isolates. PFGE identified 12 and 9 genotypes in the BP and NBP isolates, respectively, with 6 genotypes shared by both groups. ST195 was the most prevalent type (40%), followed by ST457 (18.9%). The pandemic clonal complex 92 was predominant, accounting for 94.3% of the strains. For all studied periods, mortality remained higher in the BP than the NBP group. Disease severity was the main risk factor for high mortality in the BP group, and other factors related to mortality were infection, and not treatment or microbiology-related.


Asunto(s)
Infecciones por Acinetobacter , Acinetobacter baumannii , Bacteriemia , Farmacorresistencia Bacteriana , Unidades de Cuidados Intensivos , Neumonía Bacteriana , Síndrome de Dificultad Respiratoria , Infecciones por Acinetobacter/tratamiento farmacológico , Infecciones por Acinetobacter/microbiología , Infecciones por Acinetobacter/mortalidad , Anciano , Anciano de 80 o más Años , Bacteriemia/tratamiento farmacológico , Bacteriemia/microbiología , Bacteriemia/mortalidad , China/epidemiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Neumonía Bacteriana/tratamiento farmacológico , Neumonía Bacteriana/microbiología , Neumonía Bacteriana/mortalidad , Prevalencia , Síndrome de Dificultad Respiratoria/tratamiento farmacológico , Síndrome de Dificultad Respiratoria/microbiología , Síndrome de Dificultad Respiratoria/mortalidad
16.
Phys Chem Chem Phys ; 19(36): 24971-24978, 2017 Sep 20.
Artículo en Inglés | MEDLINE | ID: mdl-28875193

RESUMEN

In π-conjugated polymers for photovoltaic applications, intrinsic conjugation defects are known to play crucial roles in impacting exciton transport after photoexcitation. However, the understanding of the associated microscopic processes still remains limited. Here, we present a theoretical investigation of the effects of different conjugation defects on the dynamics of exciton transport in two linearly coupled poly(p-phenylene vinylene) (PPV) molecules. The model system is constructed by employing an extended version of the Su-Schrieffer-Heeger model and the exciton behaviors are simulated by means of a quantum nonadiabatic dynamics. We identify two types of conjugation defects, i.e., weakening conjugation and strengthening conjugation, which are demonstrated to play different roles in impacting the dynamics of exciton transport in the system. The weakening conjugation acts as an energy well inclined to trap a moving exciton, while the strengthening conjugation acts as an energy barrier inclined to block the exciton. We also systematically simulate both intrachain and interchain dynamics of exciton transport, and find that an exciton could experience a "short-time delaying", "trapping", "blocking", or "hopping" process, which is determined by the defect type, strength, and position. These findings provide a microscopic understanding of how the exciton transport dynamics can be impacted by conjugation defects in an actual polymer system.

17.
Eur J Med Chem ; 127: 166-173, 2017 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-28061346

RESUMEN

In our previous research, 9-bromo indolizinoquinoline-5,12-dione 1 has been found to be a good anti-MRSA agent. However, it had very low bioavailability in vivo possibly due to its low solubility in water. In order to obtain the derivatives with higher anti-MRSA activity and good water solubility, twenty eight bromo-substituted indolizinoquinoline-5,12-dione derivatives were synthesized in the present study. The antibacterial activity of the synthesized compounds was evaluated against one gram-negative and some gram-positive bacterial strains including 100 clinical MRSA strains. The UV assays were carried out to determine the solubility of six active compounds 16, 21, 23 and 27-29. The most potent compound 28 exhibited strong activity against clinical MRSA strains with both MIC50 and MIC90 values lower than 7.8 ng/mL. Compound 27 had good water solubility of 1.98 mg/mL and strong activity against clinical MRSA strains with MIC50 value of 63 ng/mL and MIC90 value of 125 ng/mL, 16-fold higher than that of Vancomycin.


Asunto(s)
Antibacterianos/síntesis química , Antibacterianos/farmacología , Quinolinas/síntesis química , Quinolinas/farmacología , Antibacterianos/química , Bacterias/efectos de los fármacos , Técnicas de Química Sintética , Humanos , Pruebas de Sensibilidad Microbiana , Quinolinas/química , Solubilidad , Agua/química
18.
Diagn Microbiol Infect Dis ; 85(1): 61-5, 2016 May.
Artículo en Inglés | MEDLINE | ID: mdl-26976720

RESUMEN

We report a case of mycotic keratitis caused by Bipolaris oryzae with predisposing trauma from a foreign body. The fungus was identified by sequencing the internal transcribed spacer region, translation elongation factor 1α (TEF1) gene, and partial glyceraldehyde-3-phosphate dehydrogenase (GPDH) gene, and the species identity was confirmed on the basis of its characteristic conidial phenotype. The patient was treated with surgical intervention and antifungal agents, including intravenous fluconazole (FLC), oral itraconazole, topical 0.15% amphotericin B eye drops, and 0.5% FLC eye drops. To our knowledge, this is the first report of mycotic keratitis caused by B. oryzae worldwide.


Asunto(s)
Ascomicetos , Queratitis/diagnóstico , Queratitis/microbiología , Infecciones Oportunistas/diagnóstico , Infecciones Oportunistas/microbiología , Anfotericina B/administración & dosificación , Anfotericina B/uso terapéutico , Antifúngicos/administración & dosificación , Antifúngicos/uso terapéutico , Ascomicetos/clasificación , Ascomicetos/citología , Ascomicetos/genética , Ascomicetos/ultraestructura , Genes Fúngicos , Humanos , Queratitis/tratamiento farmacológico , Masculino , Persona de Mediana Edad , Soluciones Oftálmicas , Infecciones Oportunistas/tratamiento farmacológico , Filogenia , Resultado del Tratamiento
19.
J Phys Condens Matter ; 27(13): 134209, 2015 Apr 10.
Artículo en Inglés | MEDLINE | ID: mdl-25764984

RESUMEN

A particular attempt to improve the efficiency of a dye sensitized solar cell is it's decoration with metal nano-particles (MNP). The MNP-plasmon induced enhancement of the local field enlarges the photoexcitation of the dyes and a subsequent improvement of the charge separation efficiency may result. In a recent work (2014 J. Phys. Chem. C 118 2812) we presented a theory of plasmon enhanced interfacial electron transfer for perylene attached to a TiO2 surface and placed in the proximity of a spherical MNP. These earlier studies are generalized here to the coupling of to up to four MNPs and to the use of somewhat altered molecular parameters. If the MNPs are placed close to each other strong hybridization of plasmon excitations appears and a broad resonance to which molecular excitations are coupled is formed. To investigate this situation the whole charge injection dynamics is described in the framework of the density matrix theory. The approach accounts for optical excitation of the dye coupled to the MNPs and considers subsequent electron injection into the rutile TiO2-cluster. Using a tight-binding model for the TiO2-system with about 10(5) atoms the electron motion in the cluster is described. We again consider short optical excitation which causes an intermediate steady state with a time-independent overall probability to have the electron injected into the cluster. This probability is used to introduce an enhancement factor which rates the influence of the MNP. Values larger than 500 are obtained.

20.
Nan Fang Yi Ke Da Xue Xue Bao ; 32(8): 1206-10, 2012 Aug.
Artículo en Chino | MEDLINE | ID: mdl-22931624

RESUMEN

OBJECTIVE: We report a case of cutaneous and subcutaneous phaeohyphomycosis caused by Exophiala jeanselmei after renal transplantation in Guangdong. A 66-year-old man who had a renal transplantation 6 years ago was admitted in October 2011 for the presence of 16 nodules (0.5-1.5 cm) found on his right middle finger, wrist and forearm for 5 months. Microscopic examination of the purulent exudate showed segmented and branched brown mycelium, and tissue biopsy and PAS staining showed fungal hyphae. The isolate was processed for morphological identification and molecular sequence analysis. A black colony was found after culture of the isolate on SDA at 26 degrees Celsius;, and small culture identified the isolate as Exophiala jeanselmei. ITS sequence analysis of the isolate showed a 100% homology with Exophiala jeanselmei. E-test strip was used in drug sensitivity test, and the isolate was sensitive to amphotericin B, voriconazole, itraconazole and fluconazole, but resistant to 5-flucytosine and caspofungin. Good response was obtained with surgical intervention, local injection and systemic antifungal treatment.


Asunto(s)
Exophiala/patogenicidad , Trasplante de Riñón/efectos adversos , Feohifomicosis/etiología , Anciano , Humanos , Masculino , Complicaciones Posoperatorias
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