Kockvelling4104

Herein we report how an anode is eroded and the eroded mass is deposited on the cathode surface at different arc currents ([Formula see text]) in a DC carbon arc discharge using roughly oriented graphite (ROG) as electrodes. It was found that the nature of anode erosion critically depends on [Formula see text] and has profound effects on the morphology of the as-synthesized cathode deposits (CDs), the conversion efficiency of the system to form the CDs and their compositions. By characterizing the as-synthesized CDs in their totality by transmission electron microscopy, Raman spectroscopy, and x-ray diffraction it was found that there exists a critical value of [Formula see text] below which the arc remains constricted, and above which the arc becomes intense. It was further found that the system can selectively generate both carbon nanotubes (CNTs) and layered-graphene sheets (LGs) when the carbon arc runs in constricted and intense modes, respectively. By the suitable adjustment of [Formula see text] it is possible to switchover between the aforementioned arc-modes. Based on the experimental results, a semi-empirical model encompassing the plausible effects of rapid and random movement of the anode spot on the used ROG anode surface was developed to provide new insights into the growth mechanism of arc-generated CNTs and LGs. The state-of-the-art presented in this paper could facilitate the carbon arc discharge route for the tailored synthesis of highly crystalline CNTs and LGs.In the past two decades, protein drugs have evolved to become the most successful and important strategy in cancer therapy. However, systematical administration of protein drugs may cause serious side effects. In order to prepare a new promising hydrophilic drugs carrier, we constructed a PEGylated hyaluronic acid nanogel (NI-MAHA-PEG nanogel) with hypoxia and enzymatic responsiveness, which can selectively release hydrophilic drugs interleukin-12 (IL-12) on demand in a tumor microenvironment. We observed that release of IL-12 from nanogels by hypoxia-responsive stimulation, nanogels have anti-tumor effects on melanoma. Compared with physiological conditions, the IL-12 release rate has achieved remarkable growth under hypoxic conditions. Similarly, the drug release rate increased significantly with the addition of 500 U ml-1 hyaluronidase. We provide a novel strategy to allow efficient delivery, on-demand release, and enhanced access of proteins to hypoxic tumor regions. The rational design of this nanogels drug delivery system can further explore the use of various drugs to treat many cancers.

In eyes closed condition, an increase of sleepiness level is associated with a decrease of the spectral electroencephalographic (EEG) power in the fast frequency rage (i.e., alpha activity) and with an increase of the power in the slow frequency range (i.e., theta activity). It was suggested that the changes in the fast and slow frequency ranges might determine two - the earlier and later - drowsiness stages preceding sleep onset, respectively.

We tested whether such spectral EEG signatures of sleepiness vary with age or gender.

The EEG signal was recorded with two-h intervals in 48 volunteers (15-67 years, 27 females) deprived from sleep between Friday evening to Sunday evening. The EEG signatures of sleepiness were calculated by the expressing each EEG spectrum as a deviation from the initial (Friday evening) EEG spectrum.

The age- and gender-specific variation in such signatures was found. Only the pattern of age-associated variation changed with an increase of sleepiness level. Two-stage response to the increase of sleepiness was confirmed, but only in younger study participants. Subjective sleepiness was associated with neither age nor gender.

In sleep deprivation research, the accounting for the age- and gender-specific variation in the spectral EEG measures of drowsiness might be recommended. The results did not reveal any disturbance of motivational function of subjective sleepiness in older study participants.

In sleep deprivation research, the accounting for the age- and gender-specific variation in the spectral EEG measures of drowsiness might be recommended. The results did not reveal any disturbance of motivational function of subjective sleepiness in older study participants.No Abstract required.The quality of reconstructed dynamic PET images, as well as the statistical reliability of the estimated pharmacokinetic parameters is often compromised by high levels of statistical noise, particularly at the voxel level. Many denoising strategies have been proposed, both in the temporal and spatial domain, which substantially improve the signal to noise ratio of the reconstructed dynamic images. However, although most filtering approaches are fairly successful in reducing the spatio-temporal inter-voxel variability, they may also average out or completely eradicate the critically important temporal signature of a transient neurotransmitter activation response that may be present in a non-steady state dynamic PET study. In this work, we explore an approach towards temporal denoising of non-steady state dynamic PET images using an artificial neural network, which was trained to identify the temporal profile of a time-activity curve, while preserving any potential activation response. We evaluated the performa higher variability in the estimated parameters of the activation response. Overall, the feed-forward network led to a similar performance as the HYPR filter in terms of spatial denoising, but led to notable improvements in terms of temporal denoising, which in turn improved the estimation activation parameters.The current review focuses towards the advancements made in the past decade in the field of nanotechnology for the early Alzheimer's disease (AD) diagnosis. This review includes the application of nanomaterials and nanosensors for the early detection of the main AD biomarkers (amyloid beta, phosphorylated tau, apolipoprotein E4 allele or APOE4, microRNAs, cholesterol, hydrogen peroxide etc) in biological fluids, to detect the biomarkers at a very low concentration ranging in pico, femto and even atto molar concentrations. The field of drug development has always aimed and is constantly working on developing disease modifying drugs, but these drugs will only succeed when given in the early disease stages. Thus, developing efficient diagnostic tools is of vital importance. Various nanomaterials such as liposomes; dendrimers; polymeric nanoparticles; coordination polymers; inorganic nanoparticles such as silica, manganese oxide, zinc oxide, iron oxide, super paramagnetic iron oxides; quantum dots, silver nanoparticles, gold nanoparticles, and carbon based nanostructures (carbon nanotubes, graphene oxide, nanofibres, nanodiamonds, carbon dots); Up-conversion nanoparticles; 2D nanomaterials; and radioactive nanoprobes have been used in constructing and improving efficiency of nano-sensors for AD biosensing at an early stage of diagnosis.Breath analysis is an alternative approach for disease diagnosis and for monitoring therapy. The lack of standardized procedures for collecting and analysing breath samples currently limits its use in clinical practice. In order to overcome this limitation, the "Peppermint Consortium" was established within the breath community to carry out breath wash-out experiments and define reference values for a panel of compounds contained in the peppermint oil capsule. Here, we present a needle trap micro-extraction technique coupled with gas chromatography and tandem mass spectrometry for a rapid and accurate determination of alpha-pinene, beta-pinene, limonene, eucalyptol, menthofuran, menthone, menthol and menthyl acetate in mixed breath samples. Detection limits between 1 and 20 pptv were observed when 25 mL of a humidified standard gas mixture were loaded into a needle trap device at a flow rate of 10 mL/min. Inter- and intra-day precisions were lower than 15%, thus confirming the reliability of the assay. Our procedure was used to analyse breath samples taken from a nominally healthy volunteer who were invited to swallow a 200 mg capsule of peppermint oil. Six samples were collected at various times within six hours of ingestion. Analyte concentrations were not affected by the sampling mode (i.e. mixed vs. end-tidal fraction), whereas respiratory rate and exhalation flow rate values slightly influenced the concentration of the target compounds in breath samples.The auditory brainstem response (ABR) audiometry is a means of assessing the functional status of the auditory neural pathway in clinic. The conventional click ABR lacks good neural synchrony and it mainly evaluates high-frequency hearing. Also, the common tone-burst ABR only detects hearing loss of a certain frequency per time. Besides, the existing chirp stimuli are designed based on average data of cochlear characteristics, ignoring individual differences amongst subjects. Therefore, this study designed a new stimulus approach based on a sweep-tone concept with a time-variant and spectrum characteristics that could be customized based on an individual's cochlear characteristics. To validate the efficiency of the proposed method, we compared its performances with the click and tone-bursts using ABR recordings from eleven normal-hearing adults. Experimental results showed that the proposed sweep-tone ABR achieved a higher amplitude compared with those elicited by the click and tone-bursts. Semagacestat chemical structure When the stimulus level or rate was varied, the sweep-tone ABR consistently elicited a larger response than the corresponding click ABR. Moreover, the sweep-tone ABR appeared earlier than the click ABR under the same conditions. Specifically, the mean wave V peak-peak amplitude of the sweep-tone ABR was 1.3 times that of the click ABR at 70 dB nHL and 20/s, in which the former saved 40% of test time. In summary, the proposed sweep-tone approach is found to be more efficient than the traditional click and tone-burst in eliciting ABR.Micropatterned cell cultures provide an important tool to understand dynamic biological processes, but often require specialized equipment and expertise. Here we present subtractive bioscribing (SuBscribe), a readily accessible and inexpensive technique to generate dynamic micropatterns in biomaterial monolayers on-the-fly. We first describe our modifications to a commercially available desktop xurographer and demonstrate the utility and limits of this system in creating micropatterned cultures by mechanically scribing patterns into a brittle, non-adhesive biomaterial layer. Patterns are sufficiently small to influence cell morphology and orientation and can be extended to pattern large areas with complex reproducible shapes. We also demonstrate the use of this system as a dynamic patterning tool for cocultures. Finally, we use this technique to explore and improve upon the well-established epithelial scratch assay, and demonstrate that robotic control of the scratching tool can be used to create custom-shaped wounds in epithelial monolayers, and that the scribing direction leaves trace remnants of matrix molecules that may significantly affect conventional implementations of this common assay.