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1.
Proc Natl Acad Sci U S A ; 119(20): e2202812119, 2022 05 17.
Artículo en Inglés | MEDLINE | ID: mdl-35533282

RESUMEN

Developing facile approaches for preparing efficient electrocatalysts is of significance to promote sustainable energy technologies. Here, we report a facile iron-oxidizing bacteria corrosion approach to construct a composite electrocatalyst of nickel­iron oxyhydroxides combined with iron oxides. The obtained electrocatalyst shows improved electrocatalytic activity and stability for oxygen evolution, with an overpotential of ∼230 mV to afford the current density of 10 mA cm−2. The incorporation of iron oxides produced by iron-oxidizing bacteria corrosion optimizes the electronic structure of nickel­iron oxyhydroxide electrodes, which accounts for the decreased free energy of oxygenate generation and the improvement of OER activity. This work demonstrates a natural bacterial corrosion approach for the facile preparation of efficient electrodes for water oxidation, which may provide interesting insights in the multidisciplinary integration of innovative nanomaterials and emerging energy technologies.


Asunto(s)
Níquel , Oxígeno , Microbiología del Agua , Corrosión , Compuestos Férricos , Hierro , Agua
2.
Small ; 19(38): e2301558, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37118852

RESUMEN

Electrochemical CO2  reduction reaction (CO2 RR) is an effective approach to address CO2  emission, promote recycling, and synthesize high-value multi-carbon (C2+ ) chemicals for storing renewable electricity in the long-term. The construction of multilayer-bound nanoreactors to achieve management of intermediate CO is a promising strategy for tandem to C2+ products. In this study, a series of Ag@Cu2 O nanoreactors consisting of an Ag-yolk and a multilayer confined Cu shell is designed to profile electrocatalytic CO2 RR reactions. The optimized Ag@Cu2 O-2 nanoreactor exhibits a 74% Faradaic efficiency during the C2+ pathway and remains stable for over 10 h at a bias current density of 100 mA cm-2 . Using the finite element method, this model determines that the certain volume of cavity in the Ag@Cu2 O nanoreactors facilitates on-site CO retention and that multilayers of Cu species favor CO capture. Density functional theory calculations illustrate that the biased generation of ethanol products may arise from the (100)/(111) interface of the Cu layer. In-depth explorations in multilayer-bound nanoreactors provide structural and interfacial guidance for sequential coupling of CO2 RR intermediates for efficient C2+ generation.

3.
Small ; 19(15): e2207474, 2023 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-36604992

RESUMEN

Developing bifunctional catalysts for oxygen electrochemical reactions is essential for high-performance electrochemical energy devices. Here, a Mott-Schottky heterojunction composed of porous cobalt-nitrogen-carbon (Co-N-C) polyhedra containing abundant metal-phosphides for reversible oxygen electrocatalysis is reported. As a demonstration, this catalyst shows excellent activity in the oxygen electrocatalysis and thus delivers outstanding performance in rechargeable zinc-air batteries (ZABs). The built-in electric field in the Mott-Schottky heterojunction can promote electron transfer in oxygen electrocatalysis. More importantly, an appropriate d-band center of the heterojunction catalyst also endows oxygen intermediates with a balanced adsorption/desorption capability, thus enhancing oxygen electrocatalysis and consequently improving the performance of ZABs. The work demonstrates an important design principle for preparing efficient multifunctional catalysts in energy conversion technologies.

4.
Small ; 19(37): e2300926, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37150851

RESUMEN

Metal single-atom and internal structural defects typically coexist in M-N-C materials obtained through the existing basic pyrolysis processes. Identifying a correlation between them to understand the structure-activity relationship and achieve efficient catalytic performance is important, particularly for the rare-earth (RE) elements with rich electron orbitals and strong coordination capabilities. Herein, a novel single-atom catalyst based on the RE element lutetium is successfully synthesized on a N-C support. Structural and simulation analyses demonstrate that the formation of a LuN6 structural site with an individual defect because of pyrolysis is thermodynamically favorable in Lu-N-C. Using KHCO3 -based electrolytes facilitates the fall of the K+ cations into the defective sites of Lu-N-C, thus enabling improved CO2 capture and activation, which increases the catalyst conductivity for Lu-N-C. In this study, the catalyst exhibits a Faradaic efficiency of 95.1% for CO at a current density of 18.2 mA cm-2 during carbon dioxide reduction reaction. This study thus provides new insights into understanding RE-N-C materials for energy utilization.

5.
Chemistry ; 29(64): e202302232, 2023 Nov 16.
Artículo en Inglés | MEDLINE | ID: mdl-37583085

RESUMEN

Transition metals and organic ligands combine to form metal-organic frameworks (MOFs), which possess distinct active sites, large specific surface areas and stable porous structures, giving them considerable promise for CO2 reduction electrocatalysis. In the present study, using spin polarisation density-functional theory, a series of 2D MOFs constructed from 3d transition metal and hexamethylene dipyrazoline quinoxaline(HADQ) were investigated. The calculated binding energies between HADQ and metal atoms for the ten TM-HADQ monolayers were strong sufficient to stably disperse the metal atoms in the HADQ monolayers. Of the ten catalysts tested, seven (Sc, Ni, Cu, Zn, Ti, V and Cr) exhibited high CO2 reduction selectivity, while Mn, Fe and Co required pH values above 2.350, 6.461 and 6.363, respectively, to exhibit CO2 reduction selectivity. HCOOH was the most important producer for Sc, Zn, Ni and Mn, while CH4 was the main producer for Ti, Cr, Fe and V. Cu and Co were less selective, producing HCHO, CH3 OH, and CH4 simultaneously at the same rate-determining step and limiting potential. The Cu-HADQ catalyst had a high overpotential for the HCHO product (1.022 V), while the other catalysts had lower overpotentials between 0.016 V and 0.792 V. Thus, these results predict TM-HADQ to show excellent activity in CO2 electrocatalytic reduction and to become a promising electrocatalyst for CO2 reduction.

6.
Org Biomol Chem ; 21(42): 8603-8616, 2023 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-37861432

RESUMEN

An efficient, mild method for direct regioselective acylation of quinazolines under metal-free conditions was developed with bis(trifluoroacetoxy)iodobenzene and trimethylsilyl azide at ambient temperature. The acylation reaction of quinazolines with aldehydes gave the corresponding acyl quinazolines in ethyl acetate with good to excellent yields and excellent functional group tolerance and site selectivity. In addition, the mechanism of the direct acylation of quinazolinone was investigated through HPLC-HRMS (high pressure liquid chromatography-high resolution mass spectrometry) and EPR (electron paramagnetic resonance) strategies.

7.
Phys Chem Chem Phys ; 25(30): 20381-20394, 2023 Aug 02.
Artículo en Inglés | MEDLINE | ID: mdl-37465923

RESUMEN

Single-atom catalysts fabricated using rare earth elements have emerged for electrocatalytic carbon dioxide reduction, but they need to be studied systematically and intensively. Herein, density functional theory was employed to determine the electrocatalytic CO2 reduction activity of rare earth-N6 porous carbon (Re = Ce, Nd, Sm, Eu, Gd, Tb, Er, Tm, Yb, and Lu) single-atom catalysts. The results revealed that the binding energy of the rare-earth atoms to the N6C monolayers in the ten studied Re-N6C monatomic catalysts is much more negative than the cohesion energy of the bulk rare-earth metal, which makes rare-earth atoms stably dispersed in the N6C skeleton. CO is the primary chemical product of electrocatalytic CO2 reduction by Ce, Eu, and Lu. The primary product of the six monatomic species, i.e., Nd, Sm, Tb, Er, Tm, and Yb, is HCOOH. The dominant product of Gd is CH4. The limiting potentials of these catalysts are in the range of 0.31-0.786 V and their overpotentials are in the range of 0.06-0.707 V, all of which are relatively low, showing that they are potential and promising electrocatalysts for CO2 reduction. Subsequently, Eu-N6C was experimentally synthesized and used for electrocatalytic CO2 reduction to obtain CO products, and the overpotential showed good agreement with the theoretically calculated values.

8.
Inorg Chem ; 61(31): 12190-12196, 2022 Aug 08.
Artículo en Inglés | MEDLINE | ID: mdl-35876745

RESUMEN

It is a significant challenge to construct chiral metal-organic frameworks (CMOFs) by developing a facile and green preparation strategy. In this work, CMOFs were first synthesized via a mechanochemical process by combining a truncated mixed ligand strategy and defect engineering theory. The simple, green, and rapid construction strategy could solvent-freely harvest gram-scale CMOFs with a hierarchical micro/mesoporous structure. The as-synthesized CMOFs were evaluated by Aldol asymmetric catalysis and exhibited excellent catalytic performance (conversion was up to 97.1%, the ee value was 44.3%, and the activity was still good after 5 cycles).

9.
Fish Shellfish Immunol ; 128: 91-100, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-35921932

RESUMEN

The effects of cottonseed protein concentrate (CPC) in place of fishmeal on the growth performance, immune response, digestive ability and intestinal microbiota of Litopenaeus vannamei were investigated in this study. L. vannamei (initial body weight: 0.42 ± 0.01g) was fed for 8 weeks by four isonitrogenous and isolipid feeds with CPC replacing fishmeal (FM) at 0% (control), 15% (CPC15), 30% (CPC30) and 45% (CPC45), respectively. At the end of the study, the final body weight (FBW), weight gain rate (WGR), specific growth rate (SGR) and protein efficiency ratio (PER) of L. vannamei in CPC15 and CPC30 groups were significantly increased, while the feed conversion ratio (FCR) of L. vannamei in the CPC30 group was significantly reduced when compared with the FM group (P < 0.05). After Vibrio parahaemolyticus infection, the cumulative mortality of L. vannamei in CPC15 within 24 hpi was significantly lower than that of the control group (P < 0.05). When compared with the control group, the activities and expression of the immunity-related enzymes in the hepatopancreas had almost the same obvious change trend in the CPC-containing groups, which indicated that the replacement for fishmeal by CPC led to significant immune response in L. vannamei. Besides, significant up-regulation of the digestive enzyme activities were observed in the CPC-containing groups. Analysis of intestinal microbiota showed that significant difference in alpha diversity existed between the CPC-containing groups and the control group. The relative abundances of several top 10 dominated species at the phylum and genus levels were significantly changed in the CPC-containing groups compared with the control group (P < 0.05). Functional prediction of the microbiota indicated that the pathway of protein digestion and absorption was significantly more abundant while the pathways of nitrotoluene degradation, aminobenzoate degradation, atrazine degradation, dioxin degradation and xylene degradation were significantly less abundant in the CPC-containing groups than the FM group (P < 0.05). In summary, optimal dietary CPC replacement of FM could improve the growth, immunity, digestive capacity and the diversities of the intestinal microbial flora of L. vannamei. However, parts of the functions of the intestinal microbial flora were decline.


Asunto(s)
Atrazina , Dioxinas , Microbioma Gastrointestinal , Penaeidae , Aminobenzoatos/farmacología , Alimentación Animal/análisis , Animales , Peso Corporal , Aceite de Semillas de Algodón , Dieta/veterinaria , Dioxinas/farmacología , Peces , Inmunidad , Inmunidad Innata , Intestinos , Xilenos/análisis , Xilenos/farmacología
10.
BMC Public Health ; 21(1): 809, 2021 04 28.
Artículo en Inglés | MEDLINE | ID: mdl-33906613

RESUMEN

BACKGROUND: As the outbreak of COVID-19, traditional face-to-face psychological intervention are difficult to achieve, so hotline becomes available and recommended strategies. The callers' characteristic could help us to study their experiences of emotional distress, as well as the reasons for calling during the pandemic, which can be used to inform future service design and delivery. METHODS: The information of 1558 callers called our hospital' s hotline for help from February 3, 2020, to March 16, 2020 were collected in the form of Tick-box and Free text, and the inductive content analysis was undertaken focusing on the reasons for caller engagement. RESULTS: It was indicated that more than half of the callers are female (59.7%), mostly between the age of 18-59 (76.5%). The average age was 37.13 ± 13.76 years old. The average duration of a call to the hotline was 10.03 ± 9.84 min. The most frequent description emotional state were anxious (45.1%) and calm (30.3%), with the sub-sequence of scared (18.2%), sad (11.9%), and angry (6.9%). All callers displayed a wide range of reasons for calling, with needing support around their emotion (64.6%), seeking practical help (44.0%), and sleep problems (20.3%) constituting the majority of calls. Among the subthemes, 314 callers thought the epidemic has made them upset, 198 asked questions about the epidemic, and 119 reported their life routines were disrupted. The prevalence of key reasons does not appear to differ over time. Through their feedback, 79.1% agreed that they felt emotionally better after calling, and 95.0% agreed that hotline had helped them. CONCLUSIONS: During the epidemic, the most concern of the public is still related to epidemics and its adverse effects. Fortunately, the hotline can be an active and effective rescue measure after an emergency happened.


Asunto(s)
COVID-19 , Líneas Directas , Adulto , China/epidemiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Pandemias , SARS-CoV-2 , Adulto Joven
11.
BMC Genomics ; 21(1): 441, 2020 Jun 26.
Artículo en Inglés | MEDLINE | ID: mdl-32590932

RESUMEN

BACKGROUND: Viruses are the most abundant biological entities on earth and play import roles in marine biogeochemical cycles. Here, viral communities in the surface water of the East China Sea (ECS) were collected from three representative regions of Yangshan Harbor (YSH), Gouqi Island (GQI), and the Yangtze River Estuary (YRE) and explored primarily through epifluorescence microscopy (EM), transmission electron microscopy (TEM), and metagenomics analysis. RESULTS: The virus-like particles (VLPs) in the surface water of the ECS were measured to be 106 to 107 VLPs/ml. Most of the isolated viral particles possessed a head-and-tail structure, but VLPs with unique morphotypes that had never before been observed in the realm of viruses were also found. The sequences related to known viruses in GenBank accounted for 21.1-22.8% of the viromic datasets from YSH, GQI, and YRE. In total, 1029 viral species were identified in the surface waters of the ECS. Among them, tailed phages turn out to make up the majority of viral communities, however a small number of Phycodnaviridae or Mimiviridae related sequences were also detected. The diversity of viruses did not appear to be a big difference among these three aquatic environments but their relative abundance was geographically variable. For example, the Pelagibacter phage HTVC010P accounted for 50.4% of the identified viral species in GQI, but only 9.1% in YSH and 11.7% in YRE. Sequences, almost identical to those of uncultured marine thaumarchaeal dsDNA viruses and magroviruses that infect Marine Group II Euryarchaeota, were confidently detected in the ECS viromes. The predominant classes of virome ORFs with functional annotations that were found were those involved in viral biogenesis. Virus-host connections, inferred from CRISPR spacer-protospacer mapping, implied newly discovered infection relationships in response to arms race between them. CONCLUSIONS: Together, both identified viruses and unknown viral assemblages observed in this study were indicative of the complex viral community composition found in the ECS. This finding fills a major gap in the dark world of oceanic viruses of China and additionally contributes to the better understanding of global marine viral diversity, composition, and distribution.


Asunto(s)
Metagenómica/métodos , Agua de Mar/virología , Virus/clasificación , Virus/ultraestructura , China , Bases de Datos Genéticas , Estuarios , Microscopía Electrónica de Transmisión , Microscopía Fluorescente , Filogenia , Virus/genética , Virus/aislamiento & purificación
12.
J Psychiatry Neurosci ; 44(2): 89-101, 2019 03 01.
Artículo en Inglés | MEDLINE | ID: mdl-30354038

RESUMEN

Background: The literature on grey-matter volume alterations in bipolar disorder is heterogeneous in its findings. Methods: Using effect-size differential mapping, we conducted a meta-analysis of grey-matter volume alterations in patients with bipolar disorder compared with healthy controls. Results: We analyzed data from 50 studies that included 1843 patients with bipolar disorder and 2289 controls. Findings revealed lower grey-matter volumes in the bilateral superior frontal gyri, left anterior cingulate cortex and right insula in patients with bipolar disorder and in patients with bipolar disorder type I. Patients with bipolar disorder in the euthymic and depressive phases had spatially distinct regions of altered grey-matter volume. Meta-regression revealed that the proportion of female patients with bipolar disorder or bipolar disorder type I was negatively correlated with regional grey-matter alteration in the right insula; the proportion of patients with bipolar disorder or bipolar disorder type I taking lithium was positively correlated with regional grey-matter alterations in the left anterior cingulate/paracingulate gyri; and the proportion of patients taking antipsychotic medications was negatively correlated with alterations in the anterior cingulate/paracingulate gyri. Limitations: This study was cross-sectional; analysis techniques, patient characteristics and clinical variables in the included studies were heterogeneous. Conclusion: Structural grey-matter abnormalities in patients with bipolar disorder and bipolar disorder type I were mainly in the prefrontal cortex and insula. Patients' mood state might affect grey-matter alterations. Abnormalities in regional grey-matter volume could be correlated with patients' specific demographic and clinical features.


Asunto(s)
Trastorno Bipolar/patología , Corteza Cerebral/patología , Sustancia Gris/patología , Imagen por Resonancia Magnética , Neuroimagen , Adulto , Trastorno Bipolar/diagnóstico por imagen , Corteza Cerebral/diagnóstico por imagen , Estudios Transversales , Sustancia Gris/diagnóstico por imagen , Humanos
13.
Int J Mol Sci ; 20(24)2019 Dec 10.
Artículo en Inglés | MEDLINE | ID: mdl-31835605

RESUMEN

Leaves of C. porrectum are rich in essential oils containing monoterpenes, sesquiterpenes and aromatic compounds, but the molecular mechanism of terpenoid biosynthesis in C. porrectum is still unclear. In this paper, the differences in the contents and compositions of terpenoids among three chemotypes were analyzed using gas chromatography mass spectrometry (GC/MS). Furthermore, the differential expression of gene transcripts in the leaf tissues of the three C. porrectum chemotypes were analyzed through a comparison of full-length transcriptomes and expression profiles. The essential oil of the three C. porrectum chemotypes leaves was mainly composed of monoterpenes. In the full-length transcriptome of C. porrectum, 104,062 transcripts with 306,337,921 total bp, an average length of 2944 bp, and an N50 length of 5449 bp, were obtained and 94025 transcripts were annotated. In the eucalyptol and linalool chemotype, the camphor and eucalyptol chemotype, and the camphor and linalool chemotype comparison groups, 21, 22 and 18 terpene synthase (TPS) unigenes were identified respectively. Three monoterpene synthase genes, CpTPS3, CpTPS5 and CpTPS9, were upregulated in the eucalyptol chemotype compared to the linalool chemotype and camphor chemotype. CpTPS1 was upregulated in the camphor chemotype compared to the linalool chemotype and the eucalyptol chemotype. CpTPS4 was upregulated in the linalool chemotype compared to the camphor chemotype and the eucalyptol chemotype. Different unigenes had different expression levels among the three chemotypes, but the unigene expression levels of the 2-C-methyl-D-erythritol 4phosphate (MEP) pathway were generally higher than those of the mevalonate acid (MVA) pathway. Quantitative reverse transcription PCR(qRT-PCR) further validated these expression levels. The present study provides new clues for the functional exploration of the terpenoid synthesis mechanism and key genes in different chemotypes of C. porrectum.


Asunto(s)
Vías Biosintéticas , Cinnamomum/genética , Perfilación de la Expresión Génica/métodos , Monoterpenos/análisis , Cinnamomum/metabolismo , Cromatografía de Gases y Espectrometría de Masas , Regulación de la Expresión Génica de las Plantas , Anotación de Secuencia Molecular , Monoterpenos/metabolismo , Aceites Volátiles/análisis , Aceites Volátiles/metabolismo , Hojas de la Planta/genética , Hojas de la Planta/metabolismo , Proteínas de Plantas/genética , Secuenciación del Exoma
14.
Hum Brain Mapp ; 39(12): 4707-4723, 2018 12.
Artículo en Inglés | MEDLINE | ID: mdl-30096212

RESUMEN

Psychotic bipolar disorder (P-BD) is a specific subset that presents greater risk of relapse and worse outcomes than nonpsychotic bipolar disorder (NP-BD). To explore the neuroanatomical bases of psychotic dimension in bipolar disorder (BD), a systematic review was carried out based on the gray matter volume (GMV) among P-BD and NP-BD patients and healthy controls (HC). Further, we conducted a meta-analysis of GMV differences between P-BD patients and HC using a whole-brain imaging approach. Our review revealed that P-BD patients exhibited smaller GMVs mainly in the prefronto-temporal and cingulate cortices, the precentral gyrus, and insula relative to HC both qualitatively and quantitatively. Qualitatively the comparison between P-BD and NP-BD patients suggested inconsistent GMV alterations mainly involving the prefrontal cortex, while NP-BD patients showed GMV deficits in local regions compared with HC. The higher proportions of female patients and patients taking psychotropic medication in P-BD and P-BD type I were associated with smaller GMV in the right precentral gyrus, and the right insula, respectively. In conclusions, psychosis in BD might be associated with specific cortical GMV deficits. Gender and psychotropic medication might have effects on the regional GMVs in P-BD patients. It is necessary to distinguish psychotic dimension in neuroimaging studies of BD.


Asunto(s)
Trastornos Psicóticos Afectivos/patología , Trastorno Bipolar/patología , Sustancia Gris/patología , Neuroimagen , Adulto , Trastornos Psicóticos Afectivos/diagnóstico por imagen , Trastornos Psicóticos Afectivos/fisiopatología , Trastorno Bipolar/diagnóstico por imagen , Trastorno Bipolar/fisiopatología , Sustancia Gris/diagnóstico por imagen , Humanos , Neuroimagen/métodos , Neuroimagen/estadística & datos numéricos
15.
Chemistry ; 24(50): 13205-13212, 2018 Sep 06.
Artículo en Inglés | MEDLINE | ID: mdl-29878461

RESUMEN

Organic micro- and nanostructures are expected to be promising candidates for micro- and nanophotonic materials with desirable properties owing to their low cost, flexible molecular design, and tunable self-assembly. Among these candidates, well-known squaraine dyes (SQs) have rarely been investigated because of their nonfluorescent properties in the solid state and because their optical behavior varies with changes in morphology. In this contribution, two novel 1,2-SQs, SQM and SQB, with strong bright-yellow to red fluorescence emission in the crystalline state, were designed and structured at the molecular level and by solvent adjustment. Their self-assembly behavior was studied, and it was revealed that the SQM assembly provided 1D microrods, whereas 1D microrods (Z-SQB⋅CH2 Cl2 ) and 2D microplates (E-SQB⋅2 CH3 OH) could be obtained from SQB assemblies through a solution-based self-assembly method. The varied assembly behaviors of these SQs were attributed to different π-π stacking interactions that resulted in different molecular conformations and packing modes. These assemblies exhibited distinct optical properties, and in particular, SQB⋅solvent assemblies showed multiple thermo- and vapochromic effects. Thus, the SQB assemblies are potential fluorescent sensors for organic solvent vapors. More importantly, favorable optical-waveguide properties were observed in these SQ-based microstructures.

16.
Angew Chem Int Ed Engl ; 57(26): 7649-7653, 2018 06 25.
Artículo en Inglés | MEDLINE | ID: mdl-29696766

RESUMEN

Water electrolysis is a promising source of hydrogen; however, technological challenges remain. Intensive efforts have focused on developing highly efficient and earth-abundant electrocatalysts for water splitting. An effective strategy is proposed, using a bifunctional tubular cobalt perselenide nanosheet electrode, in which the sluggish oxygen evolution reaction is substituted with anodic hydrazine oxidation so as to assist energy-efficient hydrogen production. Specifically, this electrode produces a current density of 10 mA cm-2 at -84 mV for hydrogen evolution and -17 mV for hydrazine oxidation in 1.0 m KOH and 0.5 m hydrazine electrolyte. An ultralow cell voltage of only 164 mV is required to generate a current density of 10 mA cm-2 for 14 hours of stable water electrolysis.

17.
Sensors (Basel) ; 17(10)2017 Oct 17.
Artículo en Inglés | MEDLINE | ID: mdl-29039772

RESUMEN

A pulsed time-of-flight (TOF) measurement-based Light Detection and Ranging (LiDAR) system is more effective for medium-long range distances. As a key ranging unit, a time-pickoff circuit based on automatic gain control (AGC) and constant fraction discriminator (CFD) is designed to reduce the walk error and the timing jitter for obtaining the accurate time interval. Compared with Cramer-Rao lower bound (CRLB) and the estimation of the timing jitter, four parameters-based Monte Carlo simulations are established to show how the range precision is influenced by the parameters, including pulse amplitude, pulse width, attenuation fraction and delay time of the CFD. Experiments were carried out to verify the relationship between the range precision and three of the parameters, exclusing pulse width. It can be concluded that two parameters of the ranging circuit (attenuation fraction and delay time) were selected according to the ranging performance of the minimum pulse amplitude. The attenuation fraction should be selected in the range from 0.2 to 0.6 to achieve high range precision. The selection criterion of the time-pickoff circuit parameters is helpful for the ranging circuit design of TOF LiDAR system.

18.
Arch Virol ; 161(11): 3189-201, 2016 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-27568013

RESUMEN

Infectious hypodermal and hematopoietic necrosis virus (IHHNV) is prevalent among farmed shrimp and results in significant reductions in shrimp production. In order to gain a better understanding of the prevalence of IHHNV in the Litopenaeus vannamei shrimp population of Shanghai, China, samples were collected during two cultivation seasons and subjected to diagnostic PCR. The results of this study showed that 167 out of 200 shrimp were positive for IHHNV, indicating a high viral prevalence (83.5 %) in farmed shrimp populations. Our results also indicated that there was a moderate correlation between IHHNV prevalence and water temperature, salinity and pH and only a slight correlation with the concentration of dissolved oxygen (DO). A mathematical model was developed in order to predict the relationship between these four characteristics of water quality and IHHNV prevalence, ultimately resulting in an estimate of the best water quality criteria (IHHNV prevalence = 0) where T = 30 °C pH = 8.0, DO = 18.3 mg/L, and salinity = 1.5 ‰. Additionally, two IHHNV genotypes were identified, the sequencing of which revealed a high similarity to the known IHHNV genotypes based on a comparison of their nucleotide and amino acid sequences. Two types of repetitive sequences were detected at both the 5' and 3' ends of the non-coding regions, which are commonly found in other IHHNV genomic sequences. Phylogenetic analysis indicated that the IHHNV Shanghai genotypes were closely related to strains from Ganyu and Sheyang, but not to strains originating from Fujian, China. This finding suggests that IHHNVs have emerged independently several times in China.


Asunto(s)
Densovirinae/clasificación , Densovirinae/aislamiento & purificación , Penaeidae/crecimiento & desarrollo , Penaeidae/virología , Animales , Acuicultura , China , Análisis por Conglomerados , ADN Viral/química , ADN Viral/genética , Densovirinae/genética , Genoma Viral , Genotipo , Concentración de Iones de Hidrógeno , Modelos Teóricos , Filogenia , Reacción en Cadena de la Polimerasa , Prevalencia , Salinidad , Análisis de Secuencia de ADN , Homología de Secuencia , Temperatura , Agua/química
19.
Analyst ; 140(15): 5099-104, 2015 Aug 07.
Artículo en Inglés | MEDLINE | ID: mdl-26102232

RESUMEN

In the present paper, a "light-up" chemsensor with a high specificity for carbon dioxide detection using a pyrimido[1,2-a]benzimidazole derivative (P1H) in liquid media has been developed. The results show that P1H reacts with carbon dioxide activated by a basic ion to form a carboxylic acid compound (P1-COOH). These results also provide a possible method for carboxylation reactions of P1H using carbon dioxide based on a vinyl carbanion. The complete reaction mechanism cycle was also described using DFT calculations.

20.
Phys Chem Chem Phys ; 17(17): 11375-81, 2015 May 07.
Artículo en Inglés | MEDLINE | ID: mdl-25850074

RESUMEN

The synergistic effect of graphene and MoS2 was investigated by using density functional theory (DFT) calculations on the enhanced photocatalytic H2 production activity of TiO2/graphene/MoS2 ternary nanoparticles. Our results indicate that it can form a weak covalent bond between the Ti atom of TiO2 nanocluster and the nearest C atom on graphene, which not only makes the original degenerate C(2p) orbital level of the graphene (part of the conduction band energy level) split, resulting in the production of a lower level of C(2p) that makes it easier to accept the excited electron from the Ti(3d) orbital, but also forms a +/- sequence electric field in the interface between them. It is conclusive that the electron moves from the TiO2 cluster to the graphene. In addition, we also find that the band gap of the TiO2 cluster can be doped by the graphene and MoS2, and the conduction band consists predominantly of C(2p), S(3p) and Mo(4d) orbital energy level near the Fermi level. These results illustrate that the excited electron will eventually accumulate in the graphene or MoS2 film, which can effectively enhance the separation between the excited electrons and the holes in the TiO2 clusters, thereby increasing the efficiency of hydrogen evolution. Our results are consistent with the experimental results, and can provide some valuable information for the design of photocatalytic composites.

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