4,686 research outputs found
Trust and obfuscation principles for quality of information in emerging pervasive environments
Non peer reviewedPostprin
The place of D-dimer and L-lactate levels in the early diagnosis of acute mesenteric ischemia
INTRODUCTION: Acute mesenteric ischemia (AMI) is an abdominal-vascular emergency which is rare and has high mortality rates (60-80 %) due to late diagnosis (1-3). Although it is known that extravascular reasons like intestinal intussusception, volvulus, strangulated hernias and obstructions can cause intestinal gangrene, these are rarely the cause of AMI (1). MATERIALS AND METHODS: In this study, we used male Wistar-Albino rats weighing 250-300 grams obtained from Pamukkale University Experimental Research Laboratory. Animals were exposed to light-dark cycles for 12 hours and had free access to food and water. They were kept in cages for 7 days to stabilise their intestinal flora. In animals of group I, nothing was made other than taking 0.5 ml blood intracardially. In other animals, abdomen was reached with midline laparotomy and superior mesenteric artery (SMA) was located. In group II (operative control group), SMA was isolated and manipulated but was not ligated. In Group III (intestinal ischemia group), SMAwas isolated and ligated with 3/0 silk tie distally to the aorta. After this process, intestinal ischemia was achieved which was confirmed by paleness and pulselessness of intestines, caecum and right colon. Later on, abdomen was closed with double 3/0 polyglactin sutures. At postoperative 1st, 4th and 6th hours 0.5 ml blood was taken intracardially from the animals in groups II and III in order to quantify D-dimer and L-lactate levels. LABORATORY TESTS: D-dimer: Blood samples which were put into tubes containing sodium citrate, were seperated from plasma with centrifugation at 4000 rpm for 7 minutes. L-lactate: Blood L-lactate levels were determined from blood taken into capillary tubes with the help of immobilised enzyme electrode technology using YSI 1500 Sport portative lactate analyzer (Yellow Springs Instruments Inc., Ohio-USA). HISTOPATHOLOGIC VERIFICATION: Two cm long intestinal samples were taken from animals in which SMA was ligated in order to achieve mesenteric ischemia and these samples were fixed in 10 % formol. DISCUSSION: As a result, in rats with SMA occlusion serum D-dimer levels were not increased significantly when compared either in the group or with the basal values of the control group and values in operative control group. Therefore, it is concluded that D-dimer is not a useful marker for early diagnosis of AMI. On the other hand, it is revealed that blood L-lactate levels began to increase significantly following 4th hour of mesenteric ischemia and it is shown that this increase continued at the 6th hour. In addition, considering the utmost importance of the early diagnosis in patients with the clinical suspicion of AMI, L-lactate seems to be a suitable marker to use in emergency departments because it is achieved with a portable device that gives fast and accurate results. Nevertheless, our results are need to be supported by clinical studies with larger patient series (Tab. 2, Fig. 11, Ref. 39). Text in PDF www.elis.sk
Migrant networks: empirical implications for the Italian bilateral trade
A significant number of empirical studies, focusing on different countries, have found a
positive link between migration and trade. This paper studies the relationship between emigration, immigration and trade using Italian data. The sample regards 51 foreign trading partners and spans from 1990 to 2005. The results suggest that: networks of Italian emigrants in foreign countries boost bilateral trade. The effects of immigrants are weak, on exports, or negative, on imports.
Results do not change when the cultural and institutional dissimilarities between countries are considered
Emigrants and immigrants networks in FDI
This paper studies the relationship between emigration, immigration and the bilateral foreign direct investments (FDI), inward and outward, between Italy and 51 foreign countries. The results suggest that the networks of Italian emigrants abroad significantly promote both inward and outward bilateral FDI. The overall influence of immigrants is weaker. Their role is positively dependent on distance for FDI inward, only
On the probabilistic min spanning tree Problem
We study a probabilistic optimization model for min spanning tree, where any vertex vi of the input-graph G(V,E) has some presence probability pi in the final instance G′ ⊂ G that will effectively be optimized. Suppose that when this “real” instance G′ becomes known, a spanning tree T, called anticipatory or a priori spanning tree, has already been computed in G and one can run a quick algorithm (quicker than one that recomputes from scratch), called modification strategy, that modifies the anticipatory tree T in order to fit G ′. The goal is to compute an anticipatory spanning tree of G such that, its modification for any G ′ ⊆ G is optimal for G ′. This is what we call probabilistic min spanning tree problem. In this paper we study complexity and approximation of probabilistic min spanning tree in complete graphs under two distinct modification strategies leading to different complexity results for the problem. For the first of the strategies developed, we also study two natural subproblems of probabilistic min spanning tree, namely, the probabilistic metric min spanning tree and the probabilistic min spanning tree 1,2 that deal with metric complete graphs and complete graphs with edge-weights either 1, or 2, respectively
Modeling convection-diffusion-reaction systems for microfluidic molecular communications with surface-based receivers in Internet of Bio-Nano Things.
We consider a microfluidic molecular communication (MC) system, where the concentration-encoded molecular messages are transported via fluid flow-induced convection and diffusion, and detected by a surface-based MC receiver with ligand receptors placed at the bottom of the microfluidic channel. The overall system is a convection-diffusion-reaction system that can only be solved by numerical methods, e.g., finite element analysis (FEA). However, analytical models are key for the information and communication technology (ICT), as they enable an optimisation framework to develop advanced communication techniques, such as optimum detection methods and reliable transmission schemes. In this direction, we develop an analytical model to approximate the expected time course of bound receptor concentration, i.e., the received signal used to decode the transmitted messages. The model obviates the need for computationally expensive numerical methods by capturing the nonlinearities caused by laminar flow resulting in parabolic velocity profile, and finite number of ligand receptors leading to receiver saturation. The model also captures the effects of reactive surface depletion layer resulting from the mass transport limitations and moving reaction boundary originated from the passage of finite-duration molecular concentration pulse over the receiver surface. Based on the proposed model, we derive closed form analytical expressions that approximate the received pulse width, pulse delay and pulse amplitude, which can be used to optimize the system from an ICT perspective. We evaluate the accuracy of the proposed model by comparing model-based analytical results to the numerical results obtained by solving the exact system model with COMSOL Multiphysics
Infrared multiple photon dissociation spectroscopy of protonated histidine and 4-phenyl imidazole
pre-printThe gas-phase structures of protonated histidine (His) and the side-chain model, protonated 4-phenyl imidazole (PhIm), are examined by infrared multiple photon dissociation (IRMPD) action spectroscopy utilizing light generated by the free electron laser FELIX. To identify the structures present in the experimental studies, the measured IRMPD spectra are compared to spectra calculated at a B3LYP/6-311+G(d,p) level of theory. Relative energies of various conformers are provided by single point energy calculations carried out at the B3LYP, B3P86, and MP2(full) levels using the 6-311+G(2d,2p) basis set. On the basis of these experiments and calculations, the IRMPD action spectrum for H+(His) is characterized by a mixture of [Nπ,Nα] and [Nπ,CO] conformers, with the former dominating. These conformers have the protonated nitrogen atom of imidazole adjacent to the side-chain (Nπ) hydrogen bonding to the backbone amino nitrogen (Nα) and to the backbone carbonyl oxygen, respectively. Comparison of the present results to recent IRMPD studies of protonated histamine, the radical His°+ cation, (HisArg),H22+(HisArg), and M+(His), where M+ = Li+, Na+, K+, Rb+, and Cs+, allows evaluation of the vibrational motions associated with the observed bands
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