Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Resultados 1 - 20 de 39
Filtrar
1.
BMC Plant Biol ; 24(1): 703, 2024 Jul 25.
Artículo en Inglés | MEDLINE | ID: mdl-39054445

RESUMEN

BACKGROUND: Fulvic acid enhances plant growth and interacts synergistically with phosphate fertilizer to alleviate the agricultural production problem of low phosphorus fertilizer utilization efficiency. However, the underlying mechanism of its action remains poorly understood. In this study, we investigated the impact of fulvic acid application with varying concentrations (0, 40, 60, 80 and 120 mg/L) on rice performance in plants grown in a hydroponic system subjected to low phosphorus stress. The rice growth phenotypes, biomass, root morphology, phosphorus uptake, and the impact of fulvic acid on the rhizosphere environment of rice, were assessed. RESULTS: The findings showed that adding appropriate concentrations of exogenous fulvic acid could promote the growth performance of rice under low phosphorus stress. Particularly at T1 (40 mg/L) and T2 (60 mg/L) over the control effectively increased rice biomass by 25.42% and 24.56%, respectively. Fulvic acid treatments stimulated root morphogenesis, up-regulated phosphate transporter genes, and facilitated phosphorus absorption and accumulation. Especially T1 (20.52%), T2 (18.10%) and T3 (20.48%) treatments significantly increased phosphorus uptake in rice, thereby alleviating low phosphorus stress. Additionally, fulvic acid elevated organic acids concentration in roots and up-regulated plasma membrane H+-ATPase genes, promoting organic acids secretion. This metabolic alteration can also alleviate low phosphorus stress in rice. CONCLUSIONS: The effect of exogenous fulvic acid on physiological indicators is concentration-dependent under low phosphorus stress, enhances rice performance and reduces reliance on phosphorus fertilizer. This provides new insights to shed light on the mechanism of alleviating low phosphorus stress in rice through fulvic acid application, an eco-friendly tool.


Asunto(s)
Benzopiranos , Oryza , Fósforo , Plantones , Oryza/efectos de los fármacos , Oryza/crecimiento & desarrollo , Oryza/metabolismo , Fósforo/metabolismo , Benzopiranos/farmacología , Plantones/efectos de los fármacos , Plantones/crecimiento & desarrollo , Plantones/metabolismo , Estrés Fisiológico/efectos de los fármacos , Raíces de Plantas/efectos de los fármacos , Raíces de Plantas/crecimiento & desarrollo , Raíces de Plantas/metabolismo , Fertilizantes , Rizosfera , Hidroponía
2.
Small ; 19(26): e2207808, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-36942684

RESUMEN

Optimizing the coordination structure and microscopic reaction environment of isolated metal sites is promising for boosting catalytic activity for electrocatalytic CO2 reduction reaction (CO2 RR) but is still challenging to achieve. Herein, a newly electrostatic induced self-assembly strategy for encapsulating isolated Ni-C3 N1 moiety into hollow nano-reactor as I-Ni SA/NHCRs is developed, which achieves FECO  of 94.91% at -0.80 V, the CO partial current density of ≈-15.35 mA cm-2 , superior to that with outer Ni-C2 N2 moiety (94.47%, ≈-12.06 mA cm-2 ), or without hollow structure (92.30%, ≈-5.39 mA cm-2 ), and high FECO of ≈98.41% at 100 mA cm-2 in flow cell. COMSOL multiphysics finite-element method and density functional theory (DFT) calculation illustrate that the excellent activity for I-Ni SA/NHCRs should be attributed to the structure-enhanced kinetics process caused by its hollow nano-reactor structure and unique Ni-C3 N1 moiety, which can enrich electron on Ni sites and positively shift d-band center to the Fermi level to accelerate the adsorption and activation of CO2 molecule and *COOH formation. Meanwhile, this strategy also successfully steers the design of encapsulating isolated iron and cobalt sites into nano-reactor, while I-Ni SA/NHCRs-based zinc-CO2 battery assembled with a peak power density of 2.54 mW cm--2 is achieved.

3.
Crit Rev Eukaryot Gene Expr ; 32(2): 11-24, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35381128

RESUMEN

Immune imbalance has become an important factor in the progression of chronic kidney disease (CKD). Molecular typing of CKD may be key to achieving precise treatment. xCell allows immune cell phenotyping in CKD. We integrated two independent microarray datasets and divided 87 CKD patients into two subgroups using unsupervised consensus clustering to study the correlation between CKD and patient sex, age, and CKD stage. We found different expression patterns and clinical characteristics between the two groups. CKD stage was more advanced in cluster I than in cluster II, and the weighted gene coexpression network analysis module characteristics showed enrichment of interferon and leukocyte-associated immune pathways in cluster I. Differentially expressed gene analysis revealed the 12 most significantly changed genes, of which sirtuin 1 (SIRT1) was significantly downregulated in cluster I. Gene set enrichment analysis identified multiple immune-related processes involved in CKD. xCell immune infiltration analysis revealed the significant upregulation of natural killer T (NKT) cells and the significant downregulation of most T and B cell types in cluster I. SIRT1 showed a significant negative correlation with NKT cell infiltration but a positive correlation with CD4+ T cell and natural killer cell infiltration. We systematically studied the molecular typing of the CKD transcriptome and estimated the degree of immune cell infiltration based on molecular subtypes. Our results indicate that different subgroups may have unique gene expression patterns and immune dysregulation patterns, thus providing a basis for precise treatment and immune research in CKD.


Asunto(s)
Perfilación de la Expresión Génica , Insuficiencia Renal Crónica , Análisis por Conglomerados , Redes Reguladoras de Genes , Humanos , Insuficiencia Renal Crónica/genética , Transcriptoma/genética
4.
Artículo en Inglés | MEDLINE | ID: mdl-34582328

RESUMEN

A strictly anaerobic, thermophilic, Gram-stain-negative bacterium, named as strain S15T, was isolated from oily sludge of Shengli oilfield in PR China. Cells of strain S15T were straight or slightly curved rods with 0.4-0.8 µm width × 1.4-3 µm length and occurred mostly in pairs or short chains. Endospore-formation was not observed. The strain grew optimally at 55 °C (range from 30-65 °C), pH 6.5 (pH 6.0-8.5) and 0-30 g l-1 NaCl (optimum with 10 g l-1 NaCl). Yeast extract was an essential growth factor for strain S15T. The major cellular fatty acid was iso-C15 : 0 (58.2 %), and the main polar lipids were amino phospholipid (APL), glycolipids (GLs) and phosphatidylethanolamine (PE). The G+C content of DNA of strain S15T was 52.2 mol%. Strain S15T shared 89.8 % 16S rRNA gene similarity with the most related organism Acetomicrobium hydrogeniformans DSM 22491T in the phylum Synergistetes. The paired genomic average amino acid identity (AAI) and percentage of conserved proteins (POCP) values showed relatedness of less than 58.0 and 39.7 % with type strains of the species in the phylum Synergistetes. On the basis of phenotypic, phylogenetic and phylogenomic evidences, strain S15T constitutes a novel species in a novel genus, for the name Thermosynergistes pyruvativorans gen. nov., sp. nov. is proposed. The type strain is S15T (=CCAM 583T=JCM 33159T). Thermosynergistaceae fam. nov. is also proposed.


Asunto(s)
Yacimiento de Petróleo y Gas , Ácido Pirúvico , Anaerobiosis , Bacterias , Técnicas de Tipificación Bacteriana , Composición de Base , ADN Bacteriano/genética , Ácidos Grasos/química , Fosfolípidos , Filogenia , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN
5.
Ann Vasc Surg ; 71: 56-64, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-32949748

RESUMEN

BACKGROUND: Abdominal aortic enlargement (AAE) is a commonly seen complication after thoracic endovascular aortic repair (TEVAR) for type B aortic dissection (TBAD). This study assessed the relationship between preoperative abdominal false lumen-perfused small branches (pre-AFLSBs) and risk of AAE after TEVAR for TBAD extending through the abdominal aorta. METHODS: One hundred and eighty-four patients with TBAD who had been treated by TEVAR at 4 hospitals in China were stratified in accordance with median pre-AFLSBs: ≤8 (group A) and >8 (group B). AAE was defined as ≥20% increase in abdominal total aortic volume, measured using imaging software featuring centerline analysis, on most recent postoperative computed tomography angiography relative to preoperative examination. Multivariable Cox proportional hazard regression was used to evaluate the relationship between the number of pre-AFLSBs and the risk of AAE after TEVAR. RESULTS: At median 12.4 months imaging follow-up, AAE was present in 65 patients at higher cumulative rate (log-rank test P < 0.001) in group B, which had more frequent partially thrombosed or patent abdominal false lumen than group A at 6-12 months (P < 0.01) and 12-24 months (P = 0.03) of follow-up. In a multivariable Cox proportional hazard regression model, the number of pre-AFLSBs was independently associated with risk of AAE after TEVAR (hazard ratio [for one increase], 1.10; 95% confidence interval, 1.00-1.21; P = 0.04) after adjustment for age, gender, dissection chronicity, Society for Vascular Surgery risk score, preoperative maximum descending aortic diameter, false lumen status of the abdominal aorta, numbers of false lumen-perfused visceral arteries, abdominal intimal larger tears, and preoperative abdominal intimal small tears, and dissection length and descending aortic length ratio. CONCLUSIONS: The number of pre-AFLSBs was positively associated with the risk of AAE after TEVAR for TBAD extending through the abdominal aorta.


Asunto(s)
Aorta Abdominal/fisiopatología , Aneurisma de la Aorta Torácica/cirugía , Disección Aórtica/cirugía , Implantación de Prótesis Vascular , Procedimientos Endovasculares , Remodelación Vascular , Adulto , Disección Aórtica/diagnóstico por imagen , Disección Aórtica/fisiopatología , Aorta Abdominal/diagnóstico por imagen , Aneurisma de la Aorta Torácica/diagnóstico por imagen , Aneurisma de la Aorta Torácica/fisiopatología , Implantación de Prótesis Vascular/efectos adversos , China , Procedimientos Endovasculares/efectos adversos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Sistema de Registros , Estudios Retrospectivos , Medición de Riesgo , Factores de Riesgo , Factores de Tiempo , Resultado del Tratamiento
6.
Int J Syst Evol Microbiol ; 70(5): 3361-3373, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-32375973

RESUMEN

A novel obligately anaerobic, thermophilic and formate-utilizing bacterium K32T was isolated from Shengli oilfield of China. Cells were straight rods (0.4-0.8 µm × 2.5-8.0 µm), Gram-stain-positive, non-spore-forming and slightly motile. Optimum growth occurred with pH of 7 and 0.5 g l-1 NaCl under temperature of 55-60 °C. Nitrate could be reduced into nitrite, syntrophic formate oxidation to methane and carbon dioxide occurred when co-culturing strain K32T and Methanothermobacter thermautotrophicus ΔH. The main cellular fatty acids were iso-C15 : 0 (24.0 %), anteiso-C15 : 0 (21.7 %), C16 : 0 (12.7 %) and C14 : 0 (10.8 %), and the main polar lipid was phosphatidylglycerol. The G+C content of the genomic DNA was 46.3 mol%. The 16S rRNA gene sequence of K32T shared ≤90.4 % of sequence similarity to closest type strains of Desulfitibacter alkalitolerans, Calderihabitans maritimus and members of the genus Moorella. Based on the phenotypic, biochemical and genotypic characterization, Zhaonella formicivorans gen. nov., sp. nov. is proposed with K32T (=CCAM 584T =DSM 107278T=CGMCC1.5297T) as the type strain, which is the first representative of Zhaonellaceae fam. nov. In addition, the order Thermoanaerobacterales and family Peptococcaceae were reclassified, and three novel families in the novel order of Moorellales ord. nov. were also proposed.


Asunto(s)
Firmicutes/clasificación , Formiatos/metabolismo , Yacimiento de Petróleo y Gas/microbiología , Filogenia , Anaerobiosis , Bacterias Anaerobias/clasificación , Bacterias Anaerobias/aislamiento & purificación , Técnicas de Tipificación Bacteriana , Composición de Base , China , ADN Bacteriano/genética , Ácidos Grasos/química , Firmicutes/aislamiento & purificación , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN
7.
Int J Syst Evol Microbiol ; 69(12): 3891-3902, 2019 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-31513009

RESUMEN

A Gram-stain-negative, rod-shaped, chemoorganotrophic and anaerobic bacterium, strain SK-G1T, was isolated from oily sludge sampled at the Shengli oilfield in PR China. Growth occurred with 0-30 g l-1 NaCl, at 40-65 °C and at pH 6.0-8.5. The predominant fatty acids were C14 : 0 and C13 : 0, and the major cellular polar lipids were phosphatidylglycerol and phosphatidylethanolamine. No respiratory quinone was detected. The genomic G+C content was 43.9 mol%. The strain had highest 16S rRNA gene sequence similarity (93.2 % identity) to Tepidanaerobacter syntrophicus DSM 15584T. The phylogenetic, phenotypic and chemotaxonomic data showed that strain SK-G1T (=CCAM 530T=KCTC 15783T=JCM 33158T) represents a novel species of a new genus Biomaibacteracetigenes gen. nov., sp. nov. The results of phylogenetic and phylogenomic analyses indicated that the genera Biomaibacter, Caldanaerovirga, Fervidicola, Tepidanaerobacter, Thermosediminibacter, Thermovenabulum and Thermovoraxformed a clade with high bootstrap support distinguishing to other taxon within the order Thermoanaerobacterales. This clade is proposed as Thermosediminibacterales ord. nov. and includes Tepidanaerobacteraceae fam. nov. and Thermosediminibacteraceae fam. nov. Emended descriptions of the order Thermoanaerobacterales and family Syntrophomonadaceae are also provided.


Asunto(s)
Bacilos Gramnegativos Anaerobios Rectos, Curvos y Espirales/clasificación , Yacimiento de Petróleo y Gas/microbiología , Filogenia , Aguas del Alcantarillado/microbiología , Técnicas de Tipificación Bacteriana , Composición de Base , China , ADN Bacteriano/genética , Ácidos Grasos/química , Bacilos Gramnegativos Anaerobios Rectos, Curvos y Espirales/aislamiento & purificación , Fosfolípidos/química , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN
8.
Clin Nephrol ; 92(1): 25-35, 2019 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-31079598

RESUMEN

BACKGROUND: In order to elucidate the epigenetic mechanism and explore new biomarkers for diabetes and diabetic nephropathy, circulating lncRNA and mRNA expression profiles of normal control, diabetes mellitus, and diabetic nephropathy patients were analyzed. MATERIALS AND METHODS: Serum samples from diabetic nephropathy patients (DN), diabetes mellitus patients without microalbuminuria (DM), and healthy controls (N) were collected. Arraystar Human LncRNA/mRNA V3.0 expression spectrum biochips were used for serum lncRNA and mRNA expression profile analysis. RESULTS: The urinary microalbumin/creatinine ratio and serum creatinine level were higher in diabetic nephropathy patients, and the estimated glomerular filtration rate (eGFR) was significantly decreased compared to that in diabetic patients and healthy controls (< 0.05). Compared with healthy controls, 245 upregulated and 680 downregulated lncRNAs were identified in the serum of diabetic patients, and 45 and 813 lncRNAs were up- and downregulated in the serum of diabetic nephropathy patients compared with diabetic patients. Levels of lncRNA-ARAP1-AS2 gradually increased during the progression of diabetes and diabetic nephropathy (2.82 times in DM/N and 2.47 times in DN/DM), whereas those of lncRNA-ARAP1-AS1 gradually decreased (2.24 times in DM/N, 4.79 times in DN/DM). Additionally, mRNA levels of their target gene ARAP1 (ArfGAP with RhoGAP domain, ankyrin repeat, and PH domain 1) gradually increased (2.25 times in DM/N and 2.45 times in DN/DM). CONCLUSION: lncRNA-ARAP1-AS1 and ARAP1-AS2 enhanced ARAP1 mRNA expression and may be involved in the pathogenesis of diabetes and DN. Circulating lncRNA-ARAP1-AS1, ARAP1-AS2, and ARAP1 may serve as new biomarkers for diabetes and diabetic nephropathy.


Asunto(s)
Proteínas Portadoras/genética , Diabetes Mellitus/genética , Nefropatías Diabéticas/genética , Proteínas Activadoras de GTPasa/genética , ARN Largo no Codificante/sangre , ARN Largo no Codificante/genética , ARN Mensajero/sangre , Adulto , Albuminuria/orina , Biomarcadores/sangre , Estudios de Casos y Controles , Creatinina/sangre , Creatinina/orina , Diabetes Mellitus/sangre , Nefropatías Diabéticas/sangre , Progresión de la Enfermedad , Regulación hacia Abajo , Femenino , Expresión Génica , Tasa de Filtración Glomerular , Humanos , Masculino , Persona de Mediana Edad , Regulación hacia Arriba
9.
Mikrochim Acta ; 186(12): 853, 2019 11 28.
Artículo en Inglés | MEDLINE | ID: mdl-31781954

RESUMEN

An electrochemical method was designed for the determination and simultaneous reduction of 4-nitrophenol (4-NP). A nitrogen-rich carbon aerogel was synthesized from the precursor of phenol, formaldehyde and melamine. Then, copper nanoparticles were embedded into the aerogel, and the resulting material was used to modify a glassy carbon electrode (GCE), which displayed excellent electrocatalytic activity. Sensitive determination of 4-NP by cyclic voltammetry in 0.5 M sulfuric acid was accomplished. Among the various compositions of Cux@NC, the electrode modified with Cu3@NC showed the strongest reduction peak, typically at a potential of -0.30 V vs. reversible hydrogen electrode (RHE). A further study shows the cyclic voltammetry potential range to extend from -0.46 to +0.44 V (vs. RHE) at a scan rate of 100 mV s-1. Differential pulse voltammetric determination of 4-NP gave a lower detection limit of 53 nM and a current sensitivity of 0.7 µA µM-1 cm-2. The method was applied to the determination of 4-NP in spiked water samples, with comparable results of HPLC. The excellent performance was attributed to the highly graphitized structure of the aerogel with its large surface area and small pore size, and the presence of Cu-N structures as active sites. Graphical abstractSchematic representation of electrochemical determination and reduction of 4-nitrophenol under the glassy carbon electrode modified with highly dispersed Cu nanoparticles embedded on nitrogen-rich carbon aerogel. W: working electrode; R: reference electrode; C: counter electrode). Left: copper nanoparticles embedded in an aerogel.

10.
J Nat Prod ; 81(1): 98-105, 2018 01 26.
Artículo en Inglés | MEDLINE | ID: mdl-29281282

RESUMEN

Concise total syntheses of the natural phytoalexins 2-hydroxy-8-(4-hydroxyphenyl)phenalen-1-one (1), 2-hydroxy-8-(3,4-dihydroxyphenyl)phenalen-1-one (2), and hydroxyanigorufone (4), together with regioisomer 3 are accomplished in 11 or 12 steps. The synthetic strategy features a Friedel-Crafts acylation to construct the 1H-phenalen-1-one tricyclic core followed by a Suzuki cross-coupling to obtain the target compounds.


Asunto(s)
Fenalenos/química , Sesquiterpenos/química , Acilación , Productos Biológicos/química , Fitoalexinas
11.
Water Sci Technol ; 77(5-6): 1179-1185, 2018 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-29528305

RESUMEN

Anti-fouling copper hydroxide nanowires (CHNs)-graphene oxide (GO) nanocomposites membrane was fabricated by a vacuum-assisted filtration self-assembly process. CHNs were covered on the surface and inserted into the interlayers of the GO nanosheets to form the rough surface and nanostructure channels. The membrane with water contact angles (CAs) of 53° and oil CAs of 155° exhibited superior stability, hydrophilicity, underwater superoleophobicity and ultralow oil adhesion, and hence it could separate the oil-water emulsion with a high efficiency of >99%. This membrane showed the combined advantages of high oil rejection rate and ultralow membrane fouling, making it promising for practical oil-water emulsion separation applications.


Asunto(s)
Cobre/química , Grafito/química , Hidróxidos/química , Membranas Artificiales , Nanocompuestos/química , Agua/química , Emulsiones , Filtración , Interacciones Hidrofóbicas e Hidrofílicas , Eliminación de Residuos Líquidos , Contaminantes Químicos del Agua , Purificación del Agua
12.
Plant Cell ; 26(7): 2939-61, 2014 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-25035401

RESUMEN

Tapetal programmed cell death (PCD) is a prerequisite for pollen grain development in angiosperms, and cysteine proteases are the most ubiquitous hydrolases involved in plant PCD. We identified a papain-like cysteine protease, CEP1, which is involved in tapetal PCD and pollen development in Arabidopsis thaliana. CEP1 is expressed specifically in the tapetum from stages 5 to 11 of anther development. The CEP1 protein first appears as a proenzyme in precursor protease vesicles and is then transported to the vacuole and transformed into the mature enzyme before rupture of the vacuole. cep1 mutants exhibited aborted tapetal PCD and decreased pollen fertility with abnormal pollen exine. A transcriptomic analysis revealed that 872 genes showed significantly altered expression in the cep1 mutants, and most of them are important for tapetal cell wall organization, tapetal secretory structure formation, and pollen development. CEP1 overexpression caused premature tapetal PCD and pollen infertility. ELISA and quantitative RT-PCR analyses confirmed that the CEP1 expression level showed a strong relationship to the degree of tapetal PCD and pollen fertility. Our results reveal that CEP1 is a crucial executor during tapetal PCD and that proper CEP1 expression is necessary for timely degeneration of tapetal cells and functional pollen formation.


Asunto(s)
Apoptosis , Proteínas de Arabidopsis/metabolismo , Arabidopsis/enzimología , Regulación de la Expresión Génica de las Plantas , Arabidopsis/genética , Arabidopsis/fisiología , Arabidopsis/ultraestructura , Proteínas de Arabidopsis/genética , Diferenciación Celular , Proteasas de Cisteína/genética , Proteasas de Cisteína/metabolismo , Flores/enzimología , Flores/genética , Flores/fisiología , Flores/ultraestructura , Modelos Genéticos , Mutación , Infertilidad Vegetal , Polen/enzimología , Polen/genética , Polen/fisiología , Polen/ultraestructura , Transporte de Proteínas , Factores de Tiempo , Vacuolas/ultraestructura
13.
Water Sci Technol ; 74(8): 1936-1945, 2016 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-27789894

RESUMEN

Through sol-gel and dip-coating processes, commercial polyurethane sponge modified by polysiloxane was fabricated under low temperature (60 °C) and atmosphere. The contact angle of the obtained polysiloxane/polyurethane sponge is 145 ± 5°. Hence, the polysiloxane/polyurethane sponge could float on water and selectively absorb organics from the surface of the water, indicating simultaneous properties of hydrophobicity and oleophilicity. The absorbent maximum value is 50-150 times of its own weight. The polysiloxane/polyurethane sponge exhibited excellent recyclability, which could be reused by squeezing the sponge due to its high mechanical stability and flexibility. Thermogravimetry-differential thermal analysis test indicated that the polysiloxane/polyurethane sponge exhibited good thermal stability and the stable contact angle of samples tested under increasing temperature indicated its good weather resistance. Due to the commercial property of polyurethane sponge and easy-handling of polysiloxane, the polysiloxane/polyurethane sponge can be easily scaled up to recover a large-area oil spill in water and further work based on the designed equipment has been under consideration.


Asunto(s)
Contaminación por Petróleo/prevención & control , Poliuretanos/química , Reciclaje , Siloxanos/química , Eliminación de Residuos Líquidos/métodos , Adsorción , Interacciones Hidrofóbicas e Hidrofílicas , Eliminación de Residuos Líquidos/economía
14.
Opt Express ; 23(3): 2879-88, 2015 Feb 09.
Artículo en Inglés | MEDLINE | ID: mdl-25836149

RESUMEN

Thermal and high speed modulation characteristics are investigated for a unidirectional-emission microdisk laser with a radius of 7 µm surrounded by BCB-cladding layer, with a threshold current of 1.5 mA at the temperature of 287 K. The lasing spectra under different widths of pulsed current are measured to characterize the temperature rise during the pulse period, and the thermal distribution in the microdisk laser is simulated by the finite-element modeling technique. A temperature rise of 25 K is estimated for the microdisk laser biased at 20 mA. Furthermore, small signal modulation response with 3dB bandwidth up to 20 GHz is obtained for the microdisk laser at the biasing current of 18 mA, and eye-diagrams at the modulation bit rates of 20, 25, and 30 GHz are also measured at the temperature of 287 K.

15.
Chem Commun (Camb) ; 60(35): 4675-4678, 2024 Apr 25.
Artículo en Inglés | MEDLINE | ID: mdl-38591667

RESUMEN

The design of stable and variable aryl linkers for conjugating drug moieties to the metabolism-related thiols is of importance in drug discovery. We disclosed that thioimidazolium groups are unique scaffolds for the thiol-(hetero)arene conjugation under mild conditions. The drug bound thioimidazolium salts, which are easily accessible via a copper-mediated Chan-Lam process in gram-scale, could be successfully applied to the late-stage coupling of bioactive thiols to construct a broad array of drug-like molecules.

16.
Opt Express ; 21(2): 2165-70, 2013 Jan 28.
Artículo en Inglés | MEDLINE | ID: mdl-23389197

RESUMEN

Defected circular resonators laterally confined by a metal layer with a flat side as an emitting window are numerically investigated based on the boundary element method for realizing unidirectional emission microlasers. The results indicate that Fabry-Pérot (FP) modes become high Q confined modes in the defected circular resonator with a metallic layer. The mode coupling between the FP mode and chaotic-like mode can result in high Q confined mode for unidirectional emission with a narrow far field pattern.


Asunto(s)
Interferometría/instrumentación , Rayos Láser , Lentes , Metales , Refractometría/instrumentación , Transductores , Diseño de Equipo , Análisis de Falla de Equipo
17.
Opt Express ; 21(13): 16069-74, 2013 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-23842394

RESUMEN

Vertical radiation loss and far-field pattern are investigated for microcylinder lasers by 3D FDTD simulation and experimentally. The numerical results show that an output waveguide connected to the microcylinder resonator can result in additional vertical radiation loss for high Q coupled modes and affect the far field pattern. The vertical radiation loss can be controlled by adjusting the up cladding layer thickness. Furthermore, two lobes of vertical far-field patterns are observed for a 15-µm-radius microcylinder laser connected with an output waveguide, which confirms the vertical radiation loss.

18.
Opt Lett ; 38(19): 3807-10, 2013 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-24081058

RESUMEN

A four-wavelength microdisk laser array laterally coupled with a bus waveguide is demonstrated numerically and experimentally. The coupled-mode characteristics as well as scattering loss in the bus waveguide caused by the connected microdisks are simulated by a 2D finite-difference time-domain technique. An AlGaInAs/InP microdisk laser array with circular radii of 10.1, 10.2, 10.3, and 10.4 µm is designed and fabricated by common photolithography and an inductively coupled-plasma etching technique. Continuous-wave electrically injected operation is realized at room temperature with the lowest threshold current of 3 mA. Four-wavelength lasing operation is realized with wavelength intervals of 3-4 nm and side mode suppression ratios larger than 25 dB. Finally, the influences of heating effect and thermal cross talk on lasing mode wavelength tuning are investigated experimentally.

19.
Front Chem ; 11: 1207947, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37601903

RESUMEN

This paper addresses the risk for environmental transmission of pathogenic microorganisms in confined spaces and the serious health hazards for personnel, and research on efficient eradication methods for the pathogenic microorganisms was carried out to provide technical support for ensuring the health of personnel in confined spaces. A series of graphene-MnO2 (G-MnO2) catalytic materials was prepared by hydrothermal and precipitation methods, and processing parameters such as the graphene doping method, the raw material ratio and the plasma action time were optimized. It was shown that G-MnOX-P/HAC prepared by a one-step precipitation method and with a graphene doping ratio of 10% had the best bactericidal effect in a dielectric barrier discharge (DBD) reactor after 4 min of reaction. The eradication rates for Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), coronavirus and Aspergillus niger were all greater than 99.9%. The characterization techniques TEM, SEM, XRD, XPS, BET and FT-IR showed that the G-MnOX-P samples prepared by the one-step precipitation method had larger specific surface areas with more oxygen vacancies and functional groups on the surfaces, which was conducive to decomposition of the ozone generated by the dissociated plasma and formation of reactive oxygen species (ROS) for the microbial eradication process. Finally, by comparing the ozone-decomposition activity with the plasma co-catalytic performance, it was verified that efficient decomposition of the ozone facilitated the eradication of microorganisms. Based on this, an analysis of the mechanism for efficient eradication was carried out.

20.
Opt Lett ; 37(11): 1977-9, 2012 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-22660093

RESUMEN

We experimentally investigate the coherence of a single mode InAlGaAs/InP cylindrical microlaser with two output waveguides. For a cylindrical microlaser with a radius of 15 µm and two 2 µm-wide output waveguides, single mode operation with a side mode suppression ratio of 30 dB is realized, and a far-field interferometric pattern similar to a Young's interferometer is observed. The results indicate that the microlasers with two output waveguides can be used as the light source for an optical sensor by monitoring the phase change of the output emission from one port versus that of the other port.

SELECCIÓN DE REFERENCIAS
Detalles de la búsqueda