3-[4-(Trifluoro­meth­yl)phen­yl]propanoic acid

In crystal of the the title compound, C10H9F3O2, inversion dimers linked by pairs of O—H⋯O hydrogen bonds occur

Nanoscale Nitrogen Doping in Silicon by Self-Assembled Monolayers

International audienceThis Report presents a nitrogen-doping method by chemically forming self-assembled monolayers on silicon. Van der Pauw technique, secondary-ion mass spectroscopy and low temperature Hall effect measurements are employed to characterize the nitrogen dopants. The experimental data show that the diffusion coefficient of nitrogen dopants is 3.66 × 10−15 cm2 s−1, 2 orders magnitude lower than that of phosphorus dopants in silicon. It is found that less than 1% of nitrogen dopants exhibit electrical activity. The analysis of Hall effect data at low temperatures indicates that the donor energy level for nitrogen dopants is located at 189 meV below the conduction band, consistent with the literature valu

The significance of Notch ligand expression in the peripheral blood of children with hand, foot and mouth disease (HFMD)

BACKGROUND: Hand, foot and mouth disease (HFMD), a virus-induced infectious disease that usually affects infants and children, has an increased incidence in China in recent years. This study attempted to investigate the role of the Notch signaling pathway in the pathogenesis of HFMD. METHODS: Eighty-two children diagnosed with HFMD were enrolled into this study. The HFMD group was further divided into the uncomplicated HFMD and HFMD with encephalitis groups. The control group included 40 children who underwent elective surgery for treatment of inguinal hernias. RESULTS: Children with HFMD displayed significantly reduced CD3+, CD3+CD4+ and CD3+CD8+ cell subsets, but substantially enhanced CD3−CD19+ cell subset (p < 0.05 versus control subjects). The expression levels of Notch ligands Dll1 and Dll4 in the peripheral blood of the HFMD group were significantly higher than those in the control group (p < 0.05). There were statistically significant differences in CD3+, CD3+CD4+ and CD3−CD19+ cell subsets, but not in Notch ligand expression, between the uncomplicated HFMD and HFMD with encephalitis groups. Dll4 expression in HFMD subjects correlated negatively with the CD3+ and CD3+CD8+ cell subsets (p < 0.05), but positively with the CD3−CD19+ cell subset (p < 0.05). Furthermore, Dll4 expression in HFMD with encephalitis subjects correlated positively with total white blood cell (WBC) counts and total protein contents in cerebrospinal fluid (CSF) (p < 0.05). CONCLUSIONS: The Notch ligand Dll4 exhibits a strong correlation with the CD3+, CD3+CD8+ and CD3−CD19+ cell subsets in children with HFMD, indicating that the Notch signaling may be involved in the development of HFMD by affecting the number and status of peripheral lymphocytes

An improved progressive triangular irregular network densification filtering algorithm for airborne LiDAR data

Airborne lidar is a technology for mapping surface spatial information and has been widely used in many areas of geospatial information disciplines. The filtering process of removing non-ground points has always been the focus of research. PTD (Progressive Triangular Irregular Network Densification) filtering algorithm is a widely used filtering algorithm for airborne lidar data. However, this algorithm has shortcomings in retaining ground points in steep areas, leading to large type Ⅰ errors. Therefore, this paper proposes an improved PTD algorithm. The improvement is the addition of the seed points filtering. Specifically, after the potential seed points are obtained by the progressive morphological filter, the seed points filtering is performed on it to remove the non-ground points, so that the obtained seed points are more accurate. The benchmark dataset of ISPRS (International Society for Photogrammetry and Remote Sensing) Working Group III is used to assess the proposed method. Results show that the method is effective in decreasing type Ⅰ error in steep areas. Comparing with the classic PTD algorithm, the type Ⅰ error and total error are decreased by 8.46% and 5.06% respectively. In addition, the proposed method shows a great advantage in computational efficiency, that is eight times more efficient than the classic PTD algorithm

Representatiivsete proovide võtmine reostunud pinnase kuhjadest

Töö keskendub representatiivsete proovide võtmisele reostunud pinnase kuhjadest. Töö esimeses pooles antakse ülevaade proovivõtu teoreetilistest alustest. Käsitletakse pinnase partii mõõtmelisust ja heterogeensust ning kirjeldatakse proovivõtul tekkivaid võimalikke proovivõtu vigu. Samuti kirjeldatakse erinevaid viise, mida saab kasutada proovi massi vähendamiseks. Töö raames viidi läbi patendi teemauuring, et saada ülevaadet leiutistest, mida saaks rakendada proovide võtmisel saastunud pinnase kuhjadest. Uuringuga leiti viis sellekohast leiutist ning nende rakendatavust on töös võrreldud. Töö raames viidi läbi ka akrediteeringu-uuring, et tuvastada, millised Eestis tegutsevad asutused ja ettevõtted omavad akrediteeringut pinnaseproovide võtmiseks ja analüüsimiseks. Leiti kolm ettevõtet akrediteeringuga naftasaaduste sisalduse määramiseks pinnases ja neist ühel on ka akrediteering pinnaseproovide võtmiseks, kuid akrediteeritud meetod ei hõlma proovivõttu pinnasekuhjadest. Proovivõtu teoorias toodud praktilisi võtteid katsetati võrdleval proovivõtmisel saastunud pinnase töötlemise väljakul ja jääkreostuse likvideerimistöö objektil. Proove võeti kokku neljast pinnasekuhjast erinevatel meetoditel ning proovi massi vähendamiseks kasutati samuti erinevaid võtteid. Saadud proovides määrati akrediteeritud laborites naftasaaduste sisaldused ning saadud tulemusi on analüüsitud ning nende põhjal on antud hinnanguid kasutatud proovivõtu meetodite kohta. Töös on antud ka praktilised soovitused representatiivseks proovivõtuks pinnasekuhjadest. Töö eesmärk kirjeldada representatiivse proovivõtu metoodika reostunud pinnase kuhjadest proovide võtmiseks on täidetud. Kuna katsetulemused ei kinnitanud esimese auna puhul olulist erinevust representatiivse ja vähem representatiivse proovivõtu metoodika vahel, siis on antud töö baasil võimalik edasi uurida proovivõtu vigade ilmnemist suurema arvu proovivõtu puhul. Samuti on võimalik katseliselt kindlaks teha, kui kaua püsivad läbisegatud aunas 0D partii omadused ehk millise aja möödudes ei anna auna pinnalt proovide võtmine enam usaldusväärseid tulemusi

Recent advances in polyoxometalate-based lanthanide–oxo clusters

Polyoxometalate (POM)-based lanthanide-oxo clusters (LnOCs) are a class of polynuclear lanthanide–oxygen complexes formed by polyoxometalate stabilization through oxygen bridges in which POMs can be viewed as multidentate inorganic ligands. POM-based LnOCs have received interest owing to their interesting structures and potential applications. In this paper, we summarize the classification, synthesis strategies, and properties of POM-based LnOCs. POM-based LnOCs are classified into three main categories according to their metal core element type and quantity: pure 4f clusters, 5d–4f clusters, and 3d–4f clusters. Their synthetic strategies are divided into four categories based on the source of the POM involved in the structural assembly: the lacunary POMs ligand-directed method, the in-situ transformation of lacunary POMs ligand-directed method, the in-situ generation of lacunary POMs ligand-directed method, and mixed synthesis strategies. In addition, the single-molecule magnets of POM-based LnOCs and their proton conduction properties are summarized

Bioactivities of berberine metabolites after transformation through CYP450 isoenzymes

<p>Abstract</p> <p>Background</p> <p>Berberine (BBR) is a drug with multiple effects on cellular energy metabolism. The present study explored answers to the question of which CYP450 (Cytochrome P450) isoenzymes execute the phase-I transformation for BBR, and what are the bioactivities of its metabolites on energy pathways.</p> <p>Methods</p> <p>BBR metabolites were detected using LC-MS/MS. Computer-assistant docking technology as well as bioassays with recombinant CYP450s were employed to identify CYP450 isoenzymes responsible for BBR phase-I transformation. Bioactivities of BBR metabolites in liver cells were examined with real time RT-PCR and kinase phosphorylation assay.</p> <p>Results</p> <p>In rat experiments, 4 major metabolites of BBR, berberrubine (M1), thalifendine (M2), demethyleneberberine (M3) and jatrorrhizine (M4) were identified in rat's livers using LC-MS/MS (liquid chromatography-tandem mass spectrometry). In the cell-free transformation reactions, M2 and M3 were detectable after incubating BBR with rCYP450s or human liver microsomes; however, M1 and M4 were below detective level. CYP2D6 and CYP1A2 played a major role in transforming BBR into M2; CYP2D6, CYP1A2 and CYP3A4 were for M3 production. The hepatocyte culture showed that BBR was active in enhancing the expression of insulin receptor (InsR) and low-density-lipoprotein receptor (LDLR) mRNA, as well as in activating AMP-activated protein kinase (AMPK). BBR's metabolites, M1-M4, remained to be active in up-regulating InsR expression with a potency reduced by 50-70%; LDLR mRNA was increased only by M1 or M2 (but not M3 and M4) with an activity level 35% or 26% of that of BBR, respectively. Similarly, AMPK-α phosphorylation was enhanced by M1 and M2 only, with a degree less than that of BBR.</p> <p>Conclusions</p> <p>Four major BBR metabolites (M1-M4) were identified after phase-I transformation in rat liver. Cell-free reactions showed that CYP2D6, CYP1A2 and CYP3A4 seemed to be the dominant CYP450 isoenzymes transforming BBR into its metabolites M2 and M3. BBR's metabolites remained to be active on BBR's targets (InsR, LDLR, and AMPK) but with reduced potency.</p