Search results for " network"
showing 10 items of 6428 documents
Hybrid Materials Formed by Two Molecular Networks. Towards Multiproperty Materials
1999
Abstract The possibilities offered by hybrid materials formed by two molecular networks in the context of the molecular magnets are illustrated. Molecule-based layered magnets are used as anionic hosts for electroactive molecules, with the aim of obtaining multiproperty materials exhibiting in addition to the cooperative magnetism other interesting properties according to the nature of the inserted molecules. In particular, hybrid molecular compounds containing molecular species giving rise to paramagnetic, conducting, or bi-stable properties are reported.
Non-exponential relaxation in disordered materials: Phenomenological correlations and spectrally selective experiments
1998
Abstract In most glass-forming materials external perturbations are relaxed in a non-exponential fashion. It is shown that the degree of non-exponentiality is phenomenologically correlated with the departure from simple thermally activated behavior as measured by the fragility index m. In model glass formers such as the Ge-As-Se ternary alloy, and to some degree for amorphous materials in general, the correlations with these properties are observed also for other characteristic features. These include the specific heat step and the aging kinetics in the glass transformation range. While phenomenological correlations have proven very useful for rationalizing the properties of many glass form…
Artificial neural network for quantitative determination of total protein in yogurt by infrared spectrometry
2009
Abstract A method has been introduced for quantitative determination of protein content in yogurt samples based on the characteristic absorbance of protein in 1800–1500 cm− 1 spectral region by mid-FTIR spectroscopy and chemometrics. Successive Projection Algorithm (SPA) wavelength selection procedure, coupled with feed forward Back-Propagation Artificial Neural Network (BP-ANN) model was the benefited chemometric technique. Relative Error of Prediction (REP) in BP-ANN and SPA-BP-ANN methods for training set was 7.25 and 3.70 respectively. Considering the complexity of the sample, the ANN model was found to be reliable, while the proposed method is rapid and simple, without any sample prepa…
Measurements of Tumor Blood Flow Using Intraperitoneal Deuterium and 2H-NMR Spectroscopy
1992
Tumors usually have a sparse, disorganized, and inefficient vascular network that leaves a large fraction of the tumor cells in an oxygen deprived and hostile metabolic microenvironment. Hence tumor blood flow, or more correctly nutritive perfusion, has important interactions with treatment efficacy. For example, hypoxic tumor cells, which occur in tumors with low blood flow, are less susceptible to radiation and are probably responsible for most radiation treatment failures (Adams, 1981). Similarly, cytotoxic drug delivery could be predicted by blood flow measurements, with clear implications regarding the expected success of chemotherapy. Thus, the ability to conveniently measure tumor bl…
Childhood Adversities and Adult Headache in Poland and Germany.
2015
Objective Various childhood adversities have been found to be associated with chronic pain in adulthood. However, associations were moderate in most studies, i.e. odds ratios (OR) were between one and two. Method An internet survey was performed in 508 Polish and 500 German subjects. A total of 19 childhood adversities were selected and their associations with headaches explored. Age, gender and country were included as potential confounders, as well as their two-way interaction with the risk factors. Results Two strong risk factors were identified. (1) A combined score for physical and emotional neglect showed an odds ratio (OR) of 2.78 (p < .002) to the frequency of headache in adulthood …
Wireless MAC processors: programming MAC protocols on commodity hardware
2012
Programmable wireless platforms aim at responding to the quest for wireless access flexibility and adaptability. This paper introduces the notion of wireless MAC processors. Instead of implementing a specific MAC protocol stack, Wireless MAC processors do support a set of Medium Access Control “commands” which can be run-time composed (programmed) through software-defined state machines, thus providing the desired MAC protocol operation. We clearly distinguish from related work in this area as, unlike other works which rely on dedicated DSPs or programmable hardware platforms, we experimentally prove the feasibility of the wireless MAC processor concept over ultra-cheap commodity WLAN hardw…
Chlorophyll Concentration Retrieval by Training Convolutional Neural Network for Stochastic Model of Leaf Optical Properties (SLOP) Inversion
2020
Miniaturized hyperspectral imaging techniques have developed rapidly in recent years and have become widely available for different applications. Combining calibrated hyperspectral imagery with inverse physically based reflectance models is an interesting approach for estimating chlorophyll concentrations that are good indicators of vegetation health. The objective of this study was to develop a novel approach for retrieving chlorophyll a and b values from remotely sensed data by inverting the stochastic model of leaf optical properties using a one-dimensional convolutional neural network. The inversion results and retrieved values are validated in two ways: A classical machine learning val…
Topological structure analysis of chromatin interaction networks.
2019
Abstract Background Current Hi-C technologies for chromosome conformation capture allow to understand a broad spectrum of functional interactions between genome elements. Although significant progress has been made into analysis of Hi-C data to identify biologically significant features, many questions still remain open, in particular regarding potential biological significance of various topological features that are characteristic for chromatin interaction networks. Results It has been previously observed that promoter capture Hi-C (PCHi-C) interaction networks tend to separate easily into well-defined connected components that can be related to certain biological functionality, however, …
Approaches to estimate the time and height at the peak maximum in liquid chromatography based on a modified Gaussian model
2011
The time and height at the peak maximum are key parameters to describe a chromatographic peak with prediction or optimization purposes, or in the qualitative/quantitative analysis of samples. Three different approaches to estimate these parameters, using the experimental points in the peak maximum region, are here described and compared. The approaches are based on the reliable description of the peak profile using a modified Gaussian model with a parabolic variance (PVMG). In the first approach, non-linear fitting of the chromatographic data to the PVMG model is carried out to obtain the time and height at the peak maximum (Approach I). In the other two approaches, the PVMG model is linear…
Characterization of chromatographic peaks using the linearly modified Gaussian model. Comparison with the bi-Gaussian and the Foley and Dorsey approa…
2017
To characterize column performance in liquid chromatography, several parameters must be obtained from experimental data. These parameters can be computed through the numerical integration of the net signal to calculate the moments after subtraction of the baseline. This requires the establishment of the peak integration limits. The whole process introduces significant uncertainty. For this reason, several alternative procedures have been proposed to measure the area, mean time and variance, based on the assumption that the chromatographic peak can be described with a mathematical function. This allows the calculation of the peak position and variance making use of the values of the experime…