Temperature dependence of tissue impedivity in electrical impedance tomography of cryosurgery

The temperature-dependent impedivity of rat liver, transverse abdominal muscle and full skin was determined in vitro as a function of frequency across the temperature range 5 degrees C to 37 degrees C and from 100 Hz to 10 kHz. This study was motivated by an increasing interest in using electrical impedance tomography (EIT) for imaging of cryosurgery and a lack of applicable data in the hypothermic range. Using a controlled-temperature impedance analyzer, it was found that as the temperature is reduced the resulting increase in tissue impedivity is more pronounced at low frequencies and that the beta dispersion, resulting from cell membrane polarization, shifts to lower frequencies. With these new data a simple case study of EIT of liver cryosurgery was examined, using a finite-element model incorporating the Pennes bio-heat equation, to determine the impact of this behavior on imaging accuracy. Overestimation of the ice-front position was found to occur if the EIT system ignored the effects of the low-temperature zone surrounding the frozen tissue. This error decreases with increasing blood perfusion and with higher measurement frequencies.     

Electrochemical behavior of carbon paste electrodes modified with methylene green immobilized on two different X type zeolites

Two new modified carbon paste electrodes (CPEs) based on two different X type zeolites, a natural zeolitic volcanic tuff (NZ) and a NaX type synthetic zeolite (SZ), modified with methylene green (MG) were developed. Cyclic voltammetry measurements revealed a reasonably fast electron transfer rate and a good stability for both investigated electrodes. The observed differences between the electrochemical behavior of MG-NZ-CPEs and MG-SZ-CPEs (the effect of pH on the formal standard potential, the magnitude of the rate constants for heterogeneous electron transfer and electrode response decay) were explained in terms of zeolites structure. The modified electrodes showed moderate electrocatalytic effect towards H₂O₂ reduction and a relatively low limit of detection (0.5 mM for MG-NZ-CPEs).     

Bellows textile muscle

The study of innovative textile muscles is useful for the construction of prototypes of active suits. These suits are obtained by inserting small pneumatic muscles into a vest. The muscles allow some movements of the upper limb to be made for rehabilitation or motor recuperation purposes. An innovative textile bellows muscle is presented in this paper, where its performances have been evaluated by means of both an analytic and a numerical model.     

Current Trends in Neurodegeneration: Cross Talks between Oxidative Stress,Cell Death,and Inflammation

The human body is highly complex and comprises a variety of living cells and extracellular material, which forms tissues, organs, and organ systems. Human cells tend to turn over readily to maintain homeostasis in tissues. However, postmitotic nerve cells exceptionally have an ability to regenerate and be sustained for the entire life of an individual, to safeguard the physiological functioning of the central nervous system. For efficient functioning of the CNS, neuronal death is essential, but extreme loss of neurons diminishes the functioning of the nervous system and leads to the onset of neurodegenerative diseases. Neurodegenerative diseases range from acute to chronic severe life-altering conditions like Parkinson’s disease and Alzheimer’s disease. Millions of individuals worldwide are suffering from neurodegenerative disorders with little or negligible treatment available, thereby leading to a decline in their quality of life. Neuropathological studies have identified a series of factors that explain the etiology of neuronal degradation and its progression in neurodegenerative disease. The onset of neurological diseases depends on a combination of factors that causes a disruption of neurons, such as environmental, biological, physiological, and genetic factors. The current review highlights some of the major pathological factors responsible for neuronal degradation, such as oxidative stress, cell death, and neuroinflammation. All these factors have been described in detail to enhance the understanding of their mechanisms and target them for disease management.     

Entrepreneurial universities and the dynamics of academic knowledge production: A case study of basic vs. applied research in Belgium

This paper explores issues related to the impact of Science-Industry relationships on the knowledge production of academic research groups, in particular on the alleged shift to the more applied research end under the influence of business partners' needs. Our findings from a case study of the Belgian Katholieke Universiteit Leuven ((K.U. Leuven) show a significant steady growth over time of publications produced by academic research groups involved in University-Industry linkages, closely related to factors both internal and external to the university that have stimulated academic entrepreneurial behaviour. On an aggregated level for 1985-2000, basic research publications appear to be more present than applied ones, both in total numbers and in growth rates. Our findings show that applied and basic research publications generally rose together in the same year. No clear and generalised evidence of a shift towards the applied research end determined by the involvement in U-I linkages was found, the weak indications of such a shift within groups coming only for groups that have already high applied versus basic orientation. These results suggest that the academic research groups examined have developed a record of applied publications without affecting their basic research publications and, rather than differentiating between applied and basic research publications, it is the combination of basic and applied publications that consolidate the group's R&D potential. Accordingly, critical assessments of the University side of the emerging 'Triple Helix' need to take into account the dynamic nature of the research dimension.     

Integration of binding peptide selection and multifunctional particles as tool-box for capture of soluble proteins in serum

In this paper, we report on a general approach for the detection of a specific tumoural biomarker directly in serum. Such detection is made possible using a protein-binding peptide selected through an improved phage display technique and then conjugated to engineered microparticles (MPs). Protein biomarkers represent an unlimited source of information for non-invasive diagnostic and prognostic tests; MP-based assays are becoming largely used in manipulation of soluble biomarkers, but their direct use in serum is hampered by the complex biomolecular environment. Our technique overcomes the current limitations as it produces a selective MP—engineered with an antifouling layer—that ‘captures’ the relevant protein staying impervious to the background. Our system succeeds in fishing-out the human tumour necrosis factor alpha directly in serum with a high selectivity degree. Our method could have great impact in soluble protein manipulation and detection for a wide variety of diagnostic applications.     

Numerical methods for minimizing real functions unimodal on a set

Abstract An extension of the classical concept of unimodality was recently proposed in [4] and slightly modified in [5]. Here we present a numerical method based on the idea of bisection for determining the minimum points of a real unimodal function on a set. A serial and a parallel algorithm are given.     

Effect of plasticizer on production of bioactive synthetic calcium phosphates/glass composites and their properties

Bioactive synthetic calcium phosphates/glass composites have been produced using PVA as a plasticizer (0, 10, 15, 20 mass%). Changes in the linear, volumetric and weight parameters of samples upon sintering at 800 °C as well as in the density, porosity and compression strength have been investigated. It was established that all of the ceramics studied (both produced with and without PVA) exhibit a linear (0.7–1.9%) and volumetric (2.3–4.9%) shrinkage, which increases with using PVA and raising its content. The microstructure examination of samples obtained with a plasticizer revealed a complex porous morphology and the presence of complex-shaped 10–50 µm pores. An increase in PVA amount led to transformation of a flake-like structure and formation of particles of regular rounded shape. The pycnometric density did not depend on using PVA and equaled 2.58–2.61 g/cm³. PVA promoted an increase in the total porosity from 24.7 to 35.8% and a decrease in the density by 1.66 to 1.89%. Porosity increased proportionally to the amount of introduced PVA and was the highest for composites produced with 20 mass% addition of PVA. Open porosity dominated in all of the composites with PVA addition. The ultimate compression strength was in the range 42–93 MPa and reduced with increasing PVA amount.     

Time-resolved explosion dynamics of H2O droplets induced by femtosecond laser pulses

Series of time-resolved still images of the explosion dynamics of micrometer-sized water droplets after femtosecond laser-pulse irradiation were obtained for different laser-pulse intensities. Amplified pulses centered around a wavelength of 805 nm with 1-mJ energy and 60-fs duration were focused onto the droplet to initiate the dynamics. Several effects, such as forward and backward plumes, jets, water films, and shock waves, were investigated. Additionally, the influence of different pulse durations produced by chirping the laser pulses was observed.