Intraepithelial leukocytes of the intestinal mucosa in normal man and in Whipple's disease

Intraepithelial lymphocytes (IEL) of the intestinal mucosa of normal man and of patients with Whipple's disease were studied by light microscopy of 1-μm-thick sections, and by electron microscopy of thin sections. IEL in normal human intestine tend to be elongated in outline, have few cytoplasmic organelles, have compact nuclei, and are unattached to epithelial cells. IEL in Whipple's disease are more likely to be activated in appearance, ie, to be larger and to contain more cytoplasmic organelles than IEL of normal intestine. The number of IEL/100 intestinal epithelial cells is similar in normal man and in patients with Whipple's disease. Other intraepithelial (IE) cells found in normal intestine include eosinophils and mast cells, and we note for the first time the presence of IE macrophages. There are no “globule leukocytes” in the intestine of normal man or of patients with Whipple's disease. Other IE cells found in the intestine in Whipple's disease include eosinophils, polymorphonuclear (PMN) leukocytes, and macrophages in untreated disease and intraepithelial macrophages in treated disease. These IE cells may be involved in the acute and chronic immune responses of the intestine.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44392/1/10620_2005_Article_BF01296750.pd

Monte Carlo investigations of the effect of beam divergence on thick, segmented crystalline scintillators for radiotherapy imaging

The use of thick, segmented scintillators in electronic portal imagers offers the potential for significant improvement in x-ray detection efficiency compared to conventional phosphor screens. Such improvement substantially increases the detective quantum efficiency (DQE), leading to the possibility of achieving soft-tissue visualization at clinically practical (i.e. low) doses using megavoltage (MV) cone-beam computed tomography. While these DQE increases are greatest at zero spatial frequency, they are diminished at higher frequencies as a result of degradation of spatial resolution due to lateral spreading of secondary radiation within the scintillator—an effect that is more pronounced for thicker scintillators. The extent of this spreading is even more accentuated for radiation impinging the scintillator at oblique angles of incidence due to beam divergence. In this paper, Monte Carlo simulations of radiation transport, performed to investigate and quantify the effects of beam divergence on the imaging performance of MV imagers based on two promising scintillators (BGO and CsI:Tl), are reported. In these studies, 10–40 mm thick scintillators, incorporating low-density polymer, or high-density tungsten septal walls, were examined for incident angles corresponding to that encountered at locations up to ~15 cm from the central beam axis (for an imager located 130 cm from a radiotherapy x-ray source). The simulations demonstrate progressively more severe spatial resolution degradation (quantified in terms of the effect on the modulation transfer function) as a function of increasing angle of incidence (as well as of the scintillator thickness). Since the noise power behavior was found to be largely independent of the incident angle, the dependence of the DQE on the incident angle is therefore primarily determined by the spatial resolution. The observed DQE degradation suggests that 10 mm thick scintillators are not strongly affected by beam divergence for detector areas up to ~30 × 30 cm2. For thicker scintillators, the area that is relatively unaffected is significantly reduced, requiring a focused scintillator geometry in order to preserve spatial resolution, and thus DQE.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/85404/1/pmb10_13_006.pd

Specialized dynamical properties of promiscuous residues revealed by simulated conformational ensembles

The ability to interact with different partners is one of the most important features in proteins. Proteins that bind a large number of partners (hubs) have been often associated with intrinsic disorder. However, many examples exist of hubs with an ordered structure, and evidence of a general mechanism promoting promiscuity in ordered proteins is still elusive. An intriguing hypothesis is that promiscuous binding sites have specific dynamical properties, distinct from the rest of the interface and pre-existing in the protein isolated state. Here, we present the first comprehensive study of the intrinsic dynamics of promiscuous residues in a large protein data set. Different computational methods, from coarse-grained elastic models to geometry-based sampling methods and to full-atom Molecular Dynamics simulations, were used to generate conformational ensembles for the isolated proteins. The flexibility and dynamic correlations of interface residues with a different degree of binding promiscuity were calculated and compared considering side chain and backbone motions, the latter both on a local and on a global scale. The study revealed that (a) promiscuous residues tend to be more flexible than nonpromiscuous ones, (b) this additional flexibility has a higher degree of organization, and (c) evolutionary conservation and binding promiscuity have opposite effects on intrinsic dynamics. Findings on simulated ensembles were also validated on ensembles of experimental structures extracted from the Protein Data Bank (PDB). Additionally, the low occurrence of single nucleotide polymorphisms observed for promiscuous residues indicated a tendency to preserve binding diversity at these positions. A case study on two ubiquitin-like proteins exemplifies how binding promiscuity in evolutionary related proteins can be modulated by the fine-tuning of the interface dynamics. The interplay between promiscuity and flexibility highlighted here can inspire new directions in protein-protein interaction prediction and design methods. © 2013 American Chemical Society

Gastric xanthomatosis and cholestasis

We report two cases of gastric xanthomatosis which developed in patients with marked cholestasis. In both cases, one with acute and one with chronic cholestasis, the gastric xanthomas disappeared with resolution of the cholestasis. A review of the literature is also provided.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44402/1/10620_2005_Article_BF01303212.pd

Electrocatalytic performance of SiO2-SWCNT nanocomposites prepared by electroassisted deposition

“The final publication is available at Springer via http://dx.doi.org/10.1007/s12678-013-0144-3”Composite materials made of porous SiO2 matrices filled with single-walled carbon nanotubes (SWCNTs) were deposited on electrodes by an electroassisted deposition method. The synthesized materials were characterized by several techniques, showing that porous silica prevents the aggregation of SWCNT on the electrodes, as could be observed by transmission electron microscopy and Raman spectroscopy. Different redox probes were employed to test their electrochemical sensing properties. The silica layer allows the permeation of the redox probes to the electrode surface and improves the electrochemical reversibility indicating an electrocatalytic effect by the incorporation of dispersed SWCNT into the silica films.This work was financed by the following research projects: MAT2010-15273 of the Spanish Ministerio de Economia y Competitividad and FEDER, PROMETEO/2013/038 of the GV, and CIVP16A1821 of the Fundacion Ramon Areces. Alonso Gamero-Quijano and David Salinas-Torres acknowledge Generalitat Valenciana (Santiago Grisolia Program) and Ministerio de Economia y Competitividad, respectively, for the funding of their research fellowships.Gamero-Quijano, A.; Huerta, F.; Salinas-Torres, D.; Morallón, E.; Montilla, F. (2013). Electrocatalytic performance of SiO2-SWCNT nanocomposites prepared by electroassisted deposition. Electrocatalysis. 4(4):259-266. https://doi.org/10.1007/s12678-013-0144-3S25926644P. Alivisatos, Nat. Biotechnol. 22, 47 (2004)S. Stankovich, D.A. Dikin, G.H. Dommett, K.M. Kohlhaas, E.J. Zimney, E.A. Stach, R.D. Piner, S.T. Nguyen, R.S. Ruoff, Nature 442, 282 (2006)D.W. Schaefer, R.S. Justice, Macromolecules 40, 8501 (2007)M. Endo, M.S. Strano, P.M. Ajayan, Carbon Nanotubes 111, 13 (2008)C.E. Banks, R.G. Compton, Analyst 131, 15 (2006)R.H. Baughman, A.A. Zakhidov, W.A. de Heer, Science 297, 787 (2002)Y.H. Lin, F. Lu, Y. Tu, Z.F. Ren, Nano Letters 4, 191 (2004)B.R. Azamian, J.J. Davis, K.S. Coleman, C.B. Bagshaw, M.L.H. Green, J. Am. Chem. Soc. 124, 12664 (2002)W. Yang, K. Ratinac, S. Ringer, P. Thordarson, J.G. Gooding, F. Braet, Angew. Chem. Int. Ed. 49, 2114 (2010)C.E. Banks, R.G. Compton, Analyst 130, 1232 (2005)L. Mazurenko, M. Etienne, O. Tananaiko, V. Zaitsev, A. Walcarius, Electrochim. Acta 83, 359 (2012)J.M.P. Paloma Yáñez-Sedeño, J. Riu, F.X. Rius, TrAC Trends in Analytical Chemistry 29, 939 (2010)Z.J. Wang, M. Etienne, S. Poller, W. Schuhmann, G.W. Kohring, V. Mamane, A. Walcarius, Electroanalysis 24, 376 (2012)R. Bandyopadhyaya, E. Nativ-Roth, O. Regev, R. Yerushalmi-Rozen, Nano Letters 2, 25 (2002)C. Park, Z. Ounaies, K.A. Watson, R.E. Crooks, J. Smith, S.E. Lowther, J.W. Connell, E.J. Siochi, J.S. Harrison, T.L.S. Clair, Chem. Phys. Lett. 364, 303 (2002)O. Matarredona, H. Rhoads, Z.R. Li, J.H. Harwell, L. Balzano, D.E. Resasco, Journal of Physical Chemistry B 107, 13357 (2003)L. Vaisman, H. Wagner, G. Marom, Advances in Colloid and Interface Science 128, 37 (2006)Y.C. Xing, Journal of Physical Chemistry B 108, 19255 (2004)J.J. Liang, Y. Huang, L. Zhang, Y. Wang, Y.F. Ma, T.Y. Guo, Y.S. Chen, Adv. Funct. Mater. 19, 2297 (2009)D. Salinas-Torres, F. Huerta, F. Montilla, E. Morallón, Electrochim. Acta 56, 2464 (2011)Z.F. Ren, Z.P. Huang, J.W. Xu, J.H. Wang, P. Bush, M.P. Siegal, P.N. Provencio, Science 282, 1105 (1998)W.Z. Li, S.S. Xie, L.X. Qian, B.H. Chang, B.S. Zou, W.Y. Zhou, R.A. Zhao, G. Wang, Science 274, 1701 (1996)M. Terrones, N. Grobert, J. Olivares, J.P. Zhang, H. Terrones, K. Kordatos, W.K. Hsu, J.P. Hare, P.D. Townsend, K. Prassides, A.K. Cheetham, H.W. Kroto, D.R.M. Walton, Nature 388, 52 (1997)R. Toledano, D. Mandler, Chem. Mater. 22, 3943 (2010)J.H. Rouse, Langmuir 21, 1055 (2005)X.B. Yan, B.K. Tay, Y. Yang, Journal of Physical Chemistry B 110, 25844 (2006)J. Lim, P. Malati, F. Bonet, B. Dunn, J. Electrochem. Soc. 154, A140 (2007)L.D. Zhu, C.Y. Tian, J.L. Zhai, R.L. Yang, Sensors and Actuators B-Chemical 125, 254 (2007)F. Montilla, M.A. Cotarelo, E. Morallón, J. Mater. Chem. 19, 305 (2009)D. Salinas-Torres, F. Montilla, F. Huerta, E. Morallón, Electrochim. Acta 56, 3620 (2011)T. Dobbins, R. Chevious, Y. Lvov, Polymers 3, 942 (2011)R. Esquembre, J.A. Poveda, C.R. Mateo, Journal of Physical Chemistry B 113, 7534 (2009)M.L. Ferrer, R. Esquembre, I. Ortega, C.R. Mateo, F. del Monte, Chem. Mater. 18, 554 (2006)M.J. O'Connell, S. Sivaram, S.K. Doorn, Physical Review B 69, 235415 (2004)C. Domingo, G. Santoro, Opt. Pura Apl 40, 175 (2007)M.S. Dresselhaus, G. Dresselhaus, R. Saito, A. Jorio, Physics Reports 409, 47 (2005)R.L. McCreery, Chem. Rev. 108, 2646 (2008)C.G. Zoski, in Handbook of Electrochemistry, 1st ed (Elsevier, Amsterdam, 2007

The Utilization of Data Analysis Techniques in Predicting Student Performance in Massive Open Online Courses (MOOCs)

The growth of the Internet has enabled the popularity of open online learning platforms to increase over the years. This has led to the inception of Massive Open Online Courses (MOOCs) that enrol, millions of people, from all over the world. Such courses operate under the concept of open learning, where content does not have to be delivered via standard mechanisms that institutions employ, such as physically attending lectures. Instead learning occurs online via recorded lecture material and online tasks. This shift has allowed more people to gain access to education, regardless of their learning background. However, despite these advancements in delivering education, completion rates for MOOCs are low. In order to investigate this issue, the paper explores the impact that technology has on open learning and identifies how data about student performance can be captured to predict trend so that at risk students can be identified before they drop-out. In achieving this, subjects surrounding student engagement and performance in MOOCs and data analysis techniques are explored to investigate how technology can be used to address this issue. The paper is then concluded with our approach of predicting behaviour and a case study of the eRegister system, which has been developed to capture and analyse data. Keywords: Open Learning; Prediction; Data Mining; Educational Systems; Massive Open Online Course; Data Analysi

Health Policy and Systems Research in Twelve Eastern Mediterranean Countries: a stocktaking of production and gaps (2000-2008)

<p>Abstract</p> <p>Background</p> <p>The objectives of this study are to: (1) profile the production of Health Policy and Systems Research (HPSR) published between 2000 and 2008 in 12 countries in the Eastern Mediterranean Region (EMR): Bahrain, Egypt, Jordan, Lebanon, Libya, Morocco, Oman, Palestine, Sudan, Syria, Tunisia, and Yemen; (2) identify gaps; and (3) assess the extent to which existing HPSR produced in the region addresses regional priorities pertaining to Health Financing, Human Resources for Health and the Role of the Non-State Sector. This is the first stocktaking paper of HPSR production and gaps in the EMR.</p> <p>Methods</p> <p>Articles indexed on Medline between years 2000 and 2008 for the 12 study countries were selected. A MeSH term based search was conducted using country names. Articles were assessed using a coding sheet adapted for the region which included themes on: Governance Arrangements, Financial Arrangements, Delivery Arrangements, and Implementation Strategies. Identified articles were matched against regional research priorities to assess the extent to which research production aligns with priorities.</p> <p>Results</p> <p>A total of 1,487 articles (11.94%) fit the criteria in the coding sheet. Results showed an increase in HPSR production which peaked after 2005. Most identified articles focused on Delivery Arrangements (68.1%), and Implementation Strategies (24.4%). Most HPSR addressed priorities in Human Resources for Health (39%<b>)</b>, and some articles focused on Health Financing (12%) and Role of the Non-State Sector (6.1%).</p> <p>Conclusions</p> <p>Despite global calls for producing and translating HPSR into policy, there are still significant gaps in the EMR. More efforts are needed to produce HPSR and align production and translation with the demand for evidence by policymakers. Findings can help inform and direct future plans and activities for the Evidence Informed Policy Network- EMR, World Health Organization- EMR, and the Middle East and North Africa Health Policy Forum, in addition to being useful for countries that host or are planning to host KT platforms in the region.</p

Utilisation of an operative difficulty grading scale for laparoscopic cholecystectomy

Background A reliable system for grading operative difficulty of laparoscopic cholecystectomy would standardise description of findings and reporting of outcomes. The aim of this study was to validate a difficulty grading system (Nassar scale), testing its applicability and consistency in two large prospective datasets. Methods Patient and disease-related variables and 30-day outcomes were identified in two prospective cholecystectomy databases: the multi-centre prospective cohort of 8820 patients from the recent CholeS Study and the single-surgeon series containing 4089 patients. Operative data and patient outcomes were correlated with Nassar operative difficultly scale, using Kendall’s tau for dichotomous variables, or Jonckheere–Terpstra tests for continuous variables. A ROC curve analysis was performed, to quantify the predictive accuracy of the scale for each outcome, with continuous outcomes dichotomised, prior to analysis. Results A higher operative difficulty grade was consistently associated with worse outcomes for the patients in both the reference and CholeS cohorts. The median length of stay increased from 0 to 4 days, and the 30-day complication rate from 7.6 to 24.4% as the difficulty grade increased from 1 to 4/5 (both p < 0.001). In the CholeS cohort, a higher difficulty grade was found to be most strongly associated with conversion to open and 30-day mortality (AUROC = 0.903, 0.822, respectively). On multivariable analysis, the Nassar operative difficultly scale was found to be a significant independent predictor of operative duration, conversion to open surgery, 30-day complications and 30-day reintervention (all p < 0.001). Conclusion We have shown that an operative difficulty scale can standardise the description of operative findings by multiple grades of surgeons to facilitate audit, training assessment and research. It provides a tool for reporting operative findings, disease severity and technical difficulty and can be utilised in future research to reliably compare outcomes according to case mix and intra-operative difficulty

Everyday legitimacy and international administration: global governance and local legitimacy in Kosovo

International administrations are a very specific form of statebuilding. This paper examines the limits illustrated by the experience in Kosovo. Here, the international administration faced the same requirements of any legitimate, Liberal government, but without the checks and balances normally associated with Liberal governance. Thus, the international administration was granted full authority and the power thereby associated, but without the legitimacy upon which the Liberal social contract rests. The state-building agenda put forth came to be seen as more exogenous, reinforcing the delegitimization process. This paper will specifically address the influence of the Weberian approach to legitimacy on the statebuilding literature, as well as its limits. It will then propose other possible avenues for statebuilding, more in line with a wider understanding of legitimacy and intervention