On a hierarchy of models for electrical conduction in biological tissues

In this paper we derive a hierarchy of models for electrical conduction in a biological tissue, which is represented by a periodic array of period ε of conducting phases surrounded by dielectric shells of thickness εη included in a conductive matrix. Such a hierarchy will be obtained from the Maxwell equations by means of a concentration process η → 0, followed by a homogenization limit with respect to ε. These models are then compared with regard to their physical meaning and mathematical issues. Copyright © 2005 John Wiley & Sons, Ltd.     

The dam problem in unbounded domains

Summary The time dependent dam problem in a general unbounded domain is studied and an existence theorem is proved by means of a rather general approximation procedure. Moreover the propagation of the support of the solution is studied in a number of geometrical situations of interest. The corresponding stationary problem is also studied and an existence theorem is proved. Finally several one-dimensional examples are given in which the solution can be either written explicitely or found solving an ordinary differential equation.This work has been supported by MURST (Italy), by I.A.N.-C.N.R. of Pavia (Italy), and by SFB 123 of University of Heidelberg (Germany).     

Some necessary and sufficient conditions for the convergence of sequences of unilateral convex sets

We establish some necessary and sufficient conditions for the convergence in $\text{W}{}_0{}^{\mathrm{1,p}}\text{(Ω)}$ of sequences of convex sets determined by obstacles. These conditions are expressed in terms of properties of the p-capacities of the level sets of the obstacles.     

Studies on the synthesis of heterocyclic compounds. XV. Preparation of a new series of macrocycles with the diglycolyl moiety

A new series of macrocycles containing the diglycolyl moiety have been prepared. The compounds prepared were: 7,9,18,20-tetrahydrodibenzo[b,k][1,4,7,10,13,16]hexaoxacyclooctadecin-6,10,17,21-tetraone ( 1 ), 1,4,7,10,13,16-hexaoxacyclooctadecane-2,6,11,15-tetraone ( 2 ), 8,7,17,18-tetramethyl-1,4,7,10,13,16-hexaoxa-cyclooctadecane-2,6,11,15-tetraone ( 3 ) and 2,5,8,15,18,21 -hexaoxatricyclo[20,4,0,0^9.14]hexacosan-3,7,16,20-tetraone ( 4 ). The compound 4 has been isolated in the four diastereoisomers: trans-syn-trans 4a , trans-anti-trans 4b , cis-syn-cis 4c and cis-anti-cis 4d .     

Electron impact mass spectrometry of some cyclic tetraesters containing a tartaric moiety

The mass spectrometric behaviour of some cyclic tetraesters containing tartaric moiety is described and discussed in detail with the aid of linked scans and exact mass measurements. The peculiar fragmentation patterns are emphasized.     

Reconstruction of cosmic and beam-halo muons with the CMS detector

The powerful muon and tracker systems of the CMS detector together with dedicated reconstruction software allow precise and efficient measurement of muon tracks originating from proton-proton collisions. The standard muon reconstruction algorithms, however, are inadequate to deal with muons that do not originate from collisions. This note discusses the design, implementation, and performance results of a dedicated cosmic muon track reconstruction algorithm, which features pattern recognition optimized for muons that are not coming from the interaction point, i.e., cosmic muons and beam-halo muons. To evaluate the performance of the new algorithm, data taken during Cosmic Challenge phases I and II were studied and compared with simulated cosmic data. In addition, a variety of more general topologies of cosmic muons and beam-halo muons were studied using simulated data to demonstrate some key features of the new algorithm.     

Influence of Freezing and Different Drying Methods on Volatile Profiles of Strawberry and Analysis of Volatile Compounds of Strawberry Commercial Jams

Strawberry is the most consumed berry fruit worldwide due to its unique aroma and flavor. Drying fruits to produce a powder represents one of the possible conservation methods to extend their shelf-life. The aim of the present study was to compare the influence of freezing and different drying methods on the volatile profile of strawberry using the HS-SPME/GC–MS method, in addition to analysis of strawberry jam volatiles. A total of 165 compounds were identified, accounting for 85.03–96.88% of the total volatile compositions. Results and PCA showed that freezing and each drying process affected the volatile profile in a different way, and the most remarkable representative differential volatiles were ethyl hexanoate, hexyl acetate, (E)-2-hexenyl acetate, mesifurane, (E)-nerolidol, γ-decalactone, 1-hexanol, and acetoin. Shade air-dried, frozen, freeze-dried, and oven-dried 45 °C samples retained more of the fruity and sweet aromas of strawberry, representing more than 68% of the total aroma intensity according to the literature. In contrast, the microwave-drying method showed drastic loss of fruity esters. Strawberry jams demonstrated complete destruction of esters and alcohols in most jams, while terpenes were significantly increased. These findings help better understand the aroma of strawberry and provide a guide for the effects of drying, freezing, and jam processing.     

Analysis of carbamate and phenylurea pesticide residues in fruit juices by solid-phase microextraction and liquid chromatography-mass spectrometry

A new analysis method to detect carbamates and phenylurea pesticide residues in fruit juices was developed using solid-phase microextraction (SPME) coupled with liquid chromatography-single quadrupole mass spectrometry (LC/MS) and liquid chromatography-quadrupole ion trap mass spectrometry (LC/QIT-MS). The pesticide residues present in watery matrices as fruit juices were extracted using three types of fibers: 50-microm Carbowax/templated resin (CW/TPR), 60-mum poly(dimethylsiloxane)/divinylbenzene (PDMS/DVB) and 85-microm polyacrylate. The different extraction conditions were evaluated choosing as the best parameters 90 min (time), 20 degrees C (temperature) and 1 ml (volume). After extraction, the desorption (in a static mode) was performed in the specific interface chamber SPME/HPLC, previously filled with 70% methanol and 30% water. The best recoveries, evaluated at two fortification levels (0.2 and 0.5 mg kg(-1)) in fruit juices, were obtained using PDMS/DVB and CW/TPR fibers, and ranged from 25 to 82% (monolinuron, diuron and diethofencarb), with relative standard deviations (RSDs) from 1 to 17%. All the limits of quantification (LOQs) were in the range of 0.005-0.05 microg ml(-1) and, in any case, equal to, or lower than, maximum residue limits (MRLs) established by Italian and Spanish legislations. The mass spectrometry analyses were carried out using an electrospray ionization (ESI) source operating in the positive mode both for single quadrupole and for QIT mass analysers, operating in selected ion monitoring (SIM) and in multiple reaction monitoring (MRM) modes, respectively. The proposed new method can be applied to the determination of selected pesticides in real samples of fruit juices.     

Well-posedness and long-time behaviour for a singular phase field system of conserved type

In this paper, we study the well-posedness of a singular non-linearpartial differential equation system and the long-time behaviourof its solutions. Namely, an equation ruling the evolution ofthe absolute temperature of the system (recently introducedin BONETTI, E., COLLI, P., FABRIZIO, M. & GILARDI, G. (2006)Modelling and long-time behaviour for phase transitions withentropy balance and thermal memory conductivity. Discrete Contin.Dyn. Syst. Ser. B, 6, 1001–1026 (electronic) and BONETTI,E., COLLI, P., FABRIZIO, M. & GILARDI, G. (2007) Globalsolution to a singular integrodifferential system related tothe entropy balance. Nonlinear Anal., 66, 1949–1979) iscoupled with a generalization of the well-known Cahn–Hilliardequation for the order parameter . In particular, under suitableassumptions on the non-linearities involved, we prove that theelements of the -limit set (i.e. the cluster points) of thetrajectories solve the steady-state system that is naturallyassociated to the evolution problem.