316 research outputs found
The effect of urbanization on ant abundance and diversity
The aim of the study was to evaluate the effect of continuous and discontinuous growth hormone treatment in Noonan's syndrome (NS) on linear growth and bone maturation. Thirty-seven children with NS aged between 5.4 and 17.5 y were treated with growth hormone (GH) in a dose of 0.15 IU kg)(-1) per day; 23 of these children were randomly assigned to one of 2 groups in a 3 y partly controlled prospective multicentre study. Group A (n = 8) immediately started GH treatment and after 2 y discontinued GH treatment for 1 y; group B (n = 15) served as a control group during the first year and started GH treatment after 1 y. After the 3 y study period, 17 out of the 23 children continued GH treatment. An additional 14 children (group C) were treated according to the same protocol, but without discontinuation of GH treatment. The effect of GH treatment for up to 3 y was evaluated in terms of gain in height standard deviation score (H-SDS) for calendar age and for bone age. Gain in H-SDS over the first year was significantly higher in the GH treatment group (+0.5) than in the non-treated group (+0.0); mean bone maturation was significantly faster in the GH treatment group (1.2 vs 0.5 y/y). Discontinuation in group A in the third study year resulted in catch-down growth (mean deltaH-SDS -0.2). Over 3 y of GH treatment, mean AH-SDS for calendar age was not significantly different between discontinuous (A: +0.8) and continuous treatment (B: +0.8; C: +1.2). Mean gain in H-SDS for bone age in the 3 groups (+0.2, 0.0. +0.3) was minimal after 3 y of GH treatment. CONCLUSION: This study confirmed the gain in H-SDS CA in Noonan's syndrome during long-term GH treatment. However, the accelerating effect of GH on bone maturation seemed to compromise the final height prognosis
Minder en anders bemesten : onderzoeksresultaten tuinbouw op klei. Rozendaal, courgette 2009
In het kader van het project Minder en Anders Bemesten is op het bedrijf van Jan en Hans van Lierop een vervolgonderzoek uitgevoerd. In een veldexperiment in herhalingen is getracht de productie van courgette gelijkmatiger in het seizoen te verdelen door op twee peilers te steunen: een bescheiden bemesting om de productie in het begin van het seizoen te verhogen, en grasklaver als voorvrucht om de productie verderop in het seizoen te verhogen. De resultaten tonen dat deze aanpak werkt: met een relatief kleine bemesting is er geen sprake van een verlaagde opbrengst in de eerste helft van de productieperiode. Verder is de bodemstructuur verbeterd door de grasklaver en is de mestgift lager dan anders het geval zou zijn geweest
The principle of a virtual multi-channel lock-in amplifier and its application to magnetoelectric measurement system
This letter presents principles and applications of a virtual multi-channel
lock-in amplifier that is a simple but effective method to recover small ac
signal from noise with high presison. The fundamentals of this method are based
on calculation of cross-correlation function. Via this method, we successfully
built up a magnetoelectric measurement system which can perform precise and
versatile measurements without any analog lock-in amplifier. Using the virtual
multi-channel lock-in amplifier, the output of the magnetoelectric measurement
system is extensively rich in magnetoelectric coupling behaviors, including
coupling strength and phase lag, under various dc bias magnetic field and ac
magnetic field.Comment: 11 pages, 6 figures. To be submitted to Rev. Sci. Instr
Spectroscopic Analysis for the Identification of Loss Mechanisms in Back-Contact Perovskite Solar Cells
Back-contact perovskite solar cells offer a significant potential to reach high efficiency due to reduced parasitic absorption from the top surface. However, the currently reported efficiencies are considerably lower (<10%) than planar perovskite solar cells (>20%). Herein, back-contact perovskite solar cells are fabricated to study loss mechanisms that cause low device efficiency. This work spatially resolves the short-circuit current, open-circuit voltage, photoluminescence quantum yield, carrier lifetime, and external quantum efficiency of the devices. The results indicate that the front surface recombination, increased nonradiative recombination at hole contact layer/perovskite interface, and the extraction barriers are three main mechanisms limiting devices from achieving high efficiencies.</p
Planty Organic: voortgang 2018
Planty Organic is a project and an experimental field in which an arable farming system is developed based on 100% nitrogen input by fixation and non-ploughing. It is started in 2012. An evaluation report has been published (Van der Burgt et al., 2017b) on the period 2012-2016. The system can be used to earn new knowledge that can be applied in the organic or conventional agriculture, on the themes of nitrogen-, phosphorus- or soil-dynamics.This report focuses on the 2018 practice and results, referring to the evaluation report. The 2018 experiences confirm the system performance as described in the evaluation. All goals are achieved: it is a productive system with a high nitrogen efficiency and a very low environmental and climate impact.The production in 2017 was roughly the level as it is expected in the evaluation. This is confirmed in a system simulation with the Ndicea model. It is not plausible that the 2017 production level will be continuously realized. Research questions remain on the internal nutrient dynamics (nitrogen and phosphorus), soil life, rooting systems and CO2 footprint
Ni-PZT-Ni Trilayered Magnetoelectric composites Synthesized by Electro-deposition
We report the high strength of magnetoelectric (ME) coupling of trilayered
composites prepared by electro-deposition. The ME coupling of Ni-lead zirconate
titanate (PZT)-Ni trilayered structure was measured ranged from1 kHz to 120
kHz. The trilayered composites exhibit high magnetoelectric voltage coefficient
because of good bonding between piezoelectric and magnetostrictive layers. The
maximum magnetoelectric voltage coefficient can be up to 33 V/cm Oe at the
electromechanical resonance frequency. This magnetoelectric effect shows
promising application in transducers for magnetoelectric energy conversion.Comment: 13 pages, 4 figure
Novel lipochitin oligosaccharide structures produced by Rhizobium etli KIM5s
Microbial Biotechnolog
High-Performance Organic Electrochemical Transistors and Neuromorphic Devices Comprising Naphthalenediimide-Dialkoxybithiazole Copolymers Bearing Glycol Ether Pendant Groups
Organic electrochemical transistors (OECTs) have emerged as building blocks for low power circuits, biosensors, and neuromorphic computing. While p-type polymer materials for OECTs are well developed, the choice of high-performance n-type polymers is limited, despite being essential for cation and metabolite biosensors, and crucial for constructing complementary circuits. N-type conjugated polymers that have efficient ion-to-electron transduction are highly desired for electrochemical applications. In this contribution, three non-fused, planar naphthalenediimide (NDI)-dialkoxybithiazole (2Tz) copolymers, which systematically increase the amount of polar tri(ethylene glycol) (TEG) side chains: PNDI2OD-2Tz (0 TEG), PNDIODTEG-2Tz (1 TEG), PNDI2TEG-2Tz (2 TEG), are reported. It is demonstrated that the OECT performance increases with the number of TEG side chains resulting from the progressively higher hydrophilicity and larger electron affinities. Benefiting from the high electron mobility, excellent ion conduction capability, efficient ion-to-electron transduction, and low-lying lowest unoccupied molecular orbital energy level, the 2 TEG polymer achieves close to 105 on-off ratio, fast switching, 1000 stable operation cycles in aqueous electrolyte, and has a long shelf life. Moreover, the higher number TEG chain substituted polymer exhibits good conductance state retention over two orders of magnitudes in electrochemical resistive random-access memory devices, highlighting its potential for neuromorphic computing
IgA N- and O-glycosylation profiling reveals no association with the pregnancy-related improvement in rheumatoid arthritis
Background: The Fc glycosylation of immunoglobulin G (IgG) is well known to associate with rheumatoid arthritis (RA) disease activity. The same may be true for other classes of Igs. In the present study, we sought to determine whether the glycosylation of IgA was different between healthy subjects and patients with RA, as well as whether it was associated with RA disease activity, in particular with the pregnancy-associated improvement thereof or the flare after delivery. Methods: A recently developed high-throughput method for glycoprofiling of IgA1 was applied to affinity-captured IgA from sera of patients with RA (n = 252) and healthy control subjects (n = 32) collected before, during and after pregnancy. Results: IgA1 O-glycans bore more sialic acids in patients with RA than in control subjects. In addition, levels of bisecting N-acetylglucosamine of the N-glycans at asparagine 144 were higher in the patients with RA. The levels of several N-glycosylation traits were shown to change with pregnancy, similar to what has been shown before for IgG. However, the changes in IgA glycosylation were not associated with improvement or a flare of disease activity. Conclusions: The glycosylation of IgA differs between patients with RA and healthy control subjects. However, our data suggest only a minor, if any, association of IgA glycosylation with RA disease activity
Fragmentation processes of ionized 5-fluorouracil in the gas phase and within clusters
We have measured mass spectra for positive ions produced from neutral 5-fluorouracil by electron impact at energies from 0 to 100 eV. Fragment ion appearance energies of this (radio-)chemotherapy agent have been determined for the first time and we have identified several new fragment ions of low abundance. The main fragmentations are similar to uracil, involving HNCO loss and subsequent HCN loss, CO loss, or FCCO loss. The features adjacent to these prominent peaks in the mass spectra are attributed to tautomerization preceding the fragmentation and/or the loss of one or two additional hydrogen atoms. A few fragmentions are distinct for 5-fluorouracil compared to uracil, most notably the production of the reactive moiety CF+. Finally, multiphoton ionization mass spectra are compared for 5-fluorouracil from a laser thermal desorption source and from a supersonic expansion source. The detection of a new fragment ion at 114 u in the supersonic expansion experiments provides the first evidence for a clustering effect on the radiation response of 5-fluorouracil. By analogy with previous experiments and calculations on protonated uracil, this is assigned to NH3 loss from protonated 5-fluorouracil
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