Effect of orlistat on fat absorption in rats: A comparison of normal rats and rats with diverted bile and pancreatic juice

Orlistat is a specific inhibitor of pancreatic and gastric lipases leading to decreased absorption of fat. In the present study, we measured the effect of orlistat on lymphatic fat transport in rats following intake of oils very different in FA composition and TAG structure, and compared this with the transport in normal rats and rats with fat malabsorption. Rats were subjected to cannulation of the main mesenteric lymph duct, and a feeding catheter was inserted into the stomach. In addition, malabsorbing rats were cannulated in the common bile and pancreatic duct. Emulsified safflower, fish, and randomized oils were administered, and lymph was collected for 24 h and analyzed for FA composition. Administration of 25 mg orlistat together with the dietary oils resulted in very small changes from baseline lymphatic transport, indicating that inhibition of the fat absorption was almost complete and furthermore that the source of fat had no influence on the inhibitory effect of orlistat. Orlistat did not interfere with the absorption of the hydrolysis products, since high absorption of sn-2 MAG and FFA (oleic acid) mixed with orlistat was observed. The baseline lymphatic transport in the orlistat group was higher than in the malabsorbing group, but this was the result of generally lower transport of endogenous FA in the malabsorbing group, presumably caused by the absence of bile FA. The transport of FA in normal rats was several-fold higher than the transport after orlistat addition and in malabsorbing rats. Thus, this study showed that orlistat inhibited fat hydrolysis, and thereby lymphatic absorption, almost completely independently of the fat administered.     

Dialysis and gel filtration of isolated low density lipoproteins do not cause a significant loss of low density lipoprotein tocopherol and carotenoid concentration

The resistance of isolated low density lipoprotein (LDL) to copper-initiated oxidation is often used as a measure of effectiveness of an antioxidant intervention. Prior to oxidation excess salt and EDTA are removed via dialysis or gel filtration of the LDL sample. However, there is concern over whether the antioxidant content of dialyzed or gel-filtered LDL is truly representative of native LDL extracted from a blood sample. Previously, the experiments done after the storage of native and dialyzed LDL at −80°C showed that the dialysis step can cause a loss of up to 60% in the tocopherol and carotenoid content of LDL. In the present study, a comparison of the micronutrient concentration in freshly prepared dialyzed and native LDL from 35 subjects showed that after the correction for cholesterol, only lycopene (13%, P<0.001) and to a lesser extent α-carotene (8%, P<0.02) were significantly decreased, and the absolute fall in concentration was far smaller than previously reported. Other experiments done with smaller numbers of samples suggested that there were minimal micronutrient losses following gel filtration and that it was important to include 10 μmol/L EDTA in the dialysis and elution buffer; otherwise micronutrient losses did occur. In summary, immediate dialysis of freshly isolated LDL in the presence of 10 μmol/L. EDTA does not cause any major loss in the concentration of tocopherol and most carotenoids.     

Double take: Parallel processing by the cerebral hemispheres reduces attentional blink.

Recent data have shown that parallel processing by the cerebral hemispheres can expand the capacity of visual working memory for spatial locations (J. F. Delvenne, 2005) and attentional tracking (G. A. Alvarez & P. Cavanagh, 2005). Evidence that parallel processing by the cerebral hemispheres can improve item identification has remained elusive. The authors used a novel variant of the attentional blink paradigm to show that the attentional blink is reduced if targets are divided between the hemispheres rather than directed to a single hemisphere. Parallel processing by the cerebral hemispheres can thus expand the capacity of processes involved in item identification. The authors also show that prior engagement of the attentional system may compromise the processing of items directed to the right visual field. This pseudoextinction may explain the failures of previous attempts to demonstrate that parallel processing can improve item identification (J. F. Delvenne, 2005; S. J. Luck, S. A. Hillyard, G. R. Mangun, & M. S. Gazzaniga, 1989). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Location Management in PCS Networks by Caching Two-Level Forwarding-Pointers

One of the challenging tasks in Personal Communication Services (PCS) is to efficiently maintain the location of PCS subscribers who move from one region to another (hereafter called mobile users). When a mobile user receives a call, the network has to quickly determine its current location. The existing location management scheme suffers from high signaling traffic in locating the mobile users. Two-level forwarding pointer scheme has been proposed from per-user forwarding pointer scheme to reduce the cost of signaling traffic. In this paper, we enhance the two-level forwarding pointer scheme. When a mobile user moves from its current Registered Area (RA), which is served by Mobile Switching Center (MSC), to another RA the local switch that acts as a parent of those two MSCs maintains this movement in its memory (hereafter called cache entry). A cache entry is used to locate rapidly the mobile user instead of querying the Home Location Register (HLR) and waiting for its reply. HLR is centralized in the network and far away from the mobile users so that the signaling traffic crossing it is expensive. Sometimes the cache entry may be failed to reach the mobile user then a two-level forwarding pointers will be created from the corresponding Visitor Location Register (VLR), attached to its MSC, through a correct path to locate the mobile user. Thus, there is a saving in cost of querying the underlying HLR. The analytical results indicate that such proposal efficiently reduces the signaling traffic cost for all values of Call to Mobility Ratio (CMR), this is especially considerable when CMR ≥1, without any increase in the call setup delay. Salah M. Ramadan (samohra@yahoo.com) received the BS and MS degrees from Computers Engineering Department, Al-Azhar University, Cairo, Egypt, in 1995 and 2002, respectively. From 2002, he was a Ph.D. student in Computers Engineering Department at Al-Azhar University and is currently pursuing the Ph.D. degree, where he is a research assistant in the Wireless Networks Branch. His research interests include traffic management in ATM networks, routing protocols, mobility management in PCS networks, and mobile computing. He is currently an instructor in Cisco Academy, Egypt. Ahmed M. El-Sherbini (Sherbini@mcit.gov.eg) received the Ph.D. in Electrical and Communication Engineering, Case Western University, U.S.A. March 1983 and M.Sc. in Communication Engineering, Cairo University, Giza, Egypt, June 1980. (M. Sc. Research Studies at the Ecole Nationale Superieure des Telecommunications (ENST), Paris, France). He is the Director, National Telecommunication Institute – Ministry of Communications and Information Technology, Egypt and Professor of Electrical and Communication Engineering Dept. Faculty of Engineering, Cairo University, Egypt. M. I. Marie received his B.Sc., M.Sc. and Ph.D. in electronic and communication engineering from Cairo University on 1972, 1981, 1985, respectively. Now he is a professor of communications at Computer and System Engineering department Al-Azhar University, Cairo, Egypt. His fields of interest includes digital communication, computer networks and protocols development. M. Zaki (azhar@mailer.scu.eun.eg) is the professor of software engineering, Computer and System Engineering Department, Faculty of Engineering, Al-Azhar University at Cairo. He received his B.Sc. and M.Sc. degrees in electrical engineering from Cairo University in 1968 and 1973 respectively. He received his Ph.D. degrees in computer engineering from Warsaw Technical University, Poland in 1977. His fields of interest include artificial intelligence, soft computing, and distributed system.     

Level set X‐FEM non‐matching meshes: application to dynamic crack propagation in elastic–plastic media

This paper develops two aspects improving crack propagation modelling with the X‐FEM method. On the one hand, it explains how one can use at the same time a regular structured mesh for a precise and efficient level set update and an unstructured irregular one for the mechanical model. On the other hand, a new numerical scheme based on the X‐FEM method is proposed for dynamic elastic–plastic situations. The simulation results are compared with two experiments on PMMA for which crack speed and crack path are provided. Copyright © 2006 John Wiley & Sons, Ltd.     

Analysis of DNA Replication by Optical Mapping in Nanochannels

DNA replication is essential to maintain genome integrity in S phase of the cell division cycle. Accumulation of stalled replication forks is a major source of genetic instability, and likely constitutes a key driver of tumorigenesis. The mechanisms of regulation of replication fork progression have therefore been extensively investigated, in particular with DNA combing, an optical mapping technique that allows the stretching of single molecules and the mapping of active region for DNA synthesis by fluorescence microscopy. DNA linearization in nanochannels has been successfully used to probe genomic information patterns along single chromosomes, and has been proposed to be a competitive alternative to DNA combing. Yet this conjecture remains to be confirmed experimentally. Here, two complementary techniques are established to detect the genomic distribution of tracks of newly synthesized DNA in human cells by optical mapping in nanochannels. Their respective advantages and limitations are compared, and applied them to detect deregulations of the replication program induced by the antitumor drug hydroxyurea. The developments here thus broaden the field of applications accessible to nanofluidic technologies, and can be used in the future as part for molecular diagnostics in the context of high throughput cancer drug screening.     

Model‐Driven and Risk‐Based Performance Analysis of Industrial Emergency Plans

This paper presents a methodology for the assessment of the performance of industrial hazardous materials emergency plans. This approach is based on a structuro‐functional model of the emergency plan, which highlights the plan's functions, resources, support services and interactions. A resource taxonomy is used to manage the complexity of the emergency response system. The model can be used both as a planning guide and for the analysis of the performance of the emergency response system, based on the risk assessment of the system. The failure probability is estimated through the plan's functions and resources fault trees. The failure severity of each function is determined by using the facility's hazard study. The failure criticality of each function is hence obtained.     

A comparison of Landsat TM and MODIS vegetation indices for estimating forage phenology in desert bighorn sheep (Ovis canadensis nelsoni) habitat in the Sonoran Desert,USA

Sonoran Desert bighorn sheep (Ovis canadensis mexicana) occupy rugged upland areas that experience irregular periods of vegetation growth associated with precipitation events. These episodic and often spatially limited events provide important forage and preformed water resources that may be important drivers of animal movement and habitat use. Habitat-use models that incorporate forage phenology would broaden our understanding of desert bighorn ecology and have considerable potential to inform conservation efforts for the species. Field-based methods are of limited utility to characterize vegetation phenology across large areas. Vegetation indices (VI) derived from satellite imagery are a viable alternative, but may be confounded by areas of high relief and shadow effects that can degrade VI values. The varying spatial and temporal resolutions of readily available satellite sensors, such as the Landsat thematic mapper (TM) and moderate-resolution imaging spectrometer (MODIS), present additional challenges. In this study, we sought to minimize degrading effects of terrain on TM- and MODIS-based estimates of vegetation phenology. We compared effects of high topographic relief on time series MODIS- and TM-based VI such as the normalized difference vegetation index (NDVI) and enhanced vegetation index (EVI) using VI departures from average (DA) in shaded and unshaded areas. Sun elevation angle negatively impacted TM-derived NDVI and EVI values in areas of steep terrain. In contrast, MODIS-derived NDVI values were insensitive to sun elevation and terrain effects, whereas MODIS-derived EVI was degraded in areas of steep terrain. Time series MODIS NDVI and EVI DA values differed significantly during months of low sun elevation angle. Average MODIS EVI departure values were ≥20% lower than NDVI under these conditions, confounding time series estimates of plant phenology. Our best results were obtained from MODIS 16-day composited NDVI. These remote-sensing-based VI estimates of seasonal plant phenology and productivity can be used to inform models of habitat use and movements of desert bighorn over large areas.     

Online multi-coloring on the path revisited

Multi-coloring on the path is a model for frequency assignment in linear cellular networks. Two models have been studied in previous papers: calls may either have finite or infinite duration. For hexagonal networks, a variation of the models where limited frequency reassignment is allowed has also been studied. We add the concept of frequency reassignment to the models of linear cellular networks and close these problems by giving matching upper and lower bounds in all cases. We prove that no randomized algorithm can have a better competitive ratio than the best deterministic algorithms. In addition, we give an exact characterization of the natural greedy algorithms for these problems. All of the above results are with regard to competitive analysis. Taking steps towards a more fine-grained analysis, we consider the case of finite calls and no frequency reassignment and prove that, even though randomization cannot bring the competitive ratio down to one, it seems that the greedy algorithm is expected optimal on uniform random request sequences. We prove this for small paths and indicate it experimentally for larger graphs.