bluuebunny/crossref_metadata_2025 huggingface dataset:
Unsteady Numerical Simulation of Flow in Draft Tube of a Hydroturbine Operating Under Various Conditions Using a Partially Averaged Navier–Stokes Model
Authors: Foroutan Hosein , Yavuzkurt Savas
Published: January 2015

The variable energy demand requires a great flexibility in operating a hydroturbine, which forces the machine to be operated far from its design point. One of the main components of a hydroturbine where undesirable flow phenomena occur under off-design conditions is the draft tube. Using computational fluid dynamics (CFD), the present paper studies the flow in the draft tube of a Francis turbine operating under various conditions. Specifically, four operating points with the same head and different flow rates corresponding to 70%, 91%, 99%, and 110% of the flow rate at the best efficiency point (BEP) are considered. Unsteady numerical simulations are performed using a recently developed partially averaged Navier–Stokes (PANS) turbulence model, and the results are compared to the available experimental data, as well as the numerical results of the traditionally used Reynolds-Averaged Navier–Stokes (RANS) models. Several parameters including the pressure recovery coefficient, mean velocity, and time-averaged and fluctuating wall pressure are investigated. It is shown that RANS and PANS both can predict the flow behavior close to the BEP operating condition. However, RANS results deviate considerably from the experimental data as the operating condition moves away from the BEP. The pressure recovery factor predicted by the RANS model shows more than 13% and 58% overprediction when the flow rate decreases to 91% and 70% of the flow rate at BEP, respectively. Predictions can be improved significantly using the present unsteady PANS simulations. Specifically, the pressure recovery factor is predicted by less than 4% and 6% deviation for these two operating conditions. A similar conclusion is reached from the analysis of the mean velocity and wall pressure data. Using unsteady PANS simulations, several transient features of the draft tube flow including the vortex rope and associated pressure fluctuations are successfully modeled. The formation of the vortex rope in partial load conditions results in severe pressure fluctuations exerting oscillatory forces on the draft tube. These pressure fluctuations are studied for several locations in the draft tube and the critical region with highest fluctuation amplitude is found to be the inner side of the elbow.
Impact Comminution of Solids Due to Progressive Crack Growth Driven by Kinetic Energy of High-Rate Shear
Authors: Bažant Zdeněk P. , Su Yewang
Published: January 2015

A new theory, inspired by analogy with turbulence, was recently proposed to model the apparent dynamic overstress due to the energy that is dissipated by material comminution during penetration of missiles into concrete walls. The high-rate interface fracture comminuting the material to small particles was considered to be driven by the release of kinetic energy of high-rate shear of the forming particles, and the corresponding energy dissipation rate was characterized in the damage constitutive law by additional viscosity. However, in spite of greatly improved predictions for missile impact and penetration, the calculation of viscosity involved two simplifications—one crude simplification in the calculation of viscosity from the shear strain rate, and another debatable simplification in treating the comminution as an instantaneous event, as in the classical rate-independent fracture mechanics. Presented is a refined theory in which both simplifications are avoided without making the theory significantly more complicated. The interface fracture is considered to be progressive and advance according to Evans' power law extended to the fast growth of interface crack area. The growth rate of interface cracks naturally leads to an additional viscosity, which allows close matching of the published test data. In combination with the microplane damage constitutive model M7 for concrete, the refined theory gives a close match of the exit velocities of missiles penetrating concrete walls of different thicknesses and of the penetration depths of missiles of different velocities into a massive block.
Unexpected maximum in the concentration dependency of the relaxation frequency of Brownian stress in a colloidal suspension
Authors: Dannert Rick , Sanctuary Roland , Baller Jörg
Published: January 2015

Concentrated and semidiluted sheared suspensions of silica nanoparticles in Diglycidyl Ether of Bisphenol A have recently been shown to exhibit a low-frequency relaxation process of the shear moduli measured by oscillatory rheology. This process, which is slower than the structural α-process of the matrix, was interpreted as Brownian stress relaxation resulting from strain-induced perturbations of the isotropic filler distribution. In this paper, we extend the rheological investigation of the low-frequency anomaly to ultra-diluted DGEBA/silica suspensions. We illustrate that the Brownian relaxation process depends in a complex manner on the filler volume concentration: For very dilute systems, the relaxation frequency increases with the concentration, whereas for semidilute or concentrated systems, the opposite behavior can be observed. This nonmonotonic dependency of the relaxation frequency leads to a maximum of the relaxation frequency at a volume concentration around 0.133. It can no longer be modeled by Peclet frequencies, since the classical Peclet frequencies depend only on a single concentration dependent physical quantity, viz., the suspension viscosity. A modified Peclet frequency depending on the suspension viscosity and the average surface-to-surface distance between the fillers as a structural, concentration dependent length scale allows for an accurate description of the Brownian relaxation for all concentrations.
Effect of Thermal State and Thermal Comfort on Cycling Performance in the Heat
Authors: Schulze Emiel , Daanen Hein A.M. , Levels Koen , Casadio Julia R. , Plews Daniel J. , Kilding Andrew E. , Siegel Rodney , Laursen Paul B.
Published: January 2015

Purpose:

To determine the effect of thermal state and thermal comfort on cycling performance in the heat.

Methods:

Seven well-trained male triathletes completed 3 performance trials consisting of 60 min cycling at a fixed rating of perceived exertion (14) followed immediately by a 20-km time trial in hot (30°C) and humid (80% relative humidity) conditions. In a randomized order, cyclists either drank ambient-temperature (30°C) fluid ad libitum during exercise (CON), drank ice slurry (−1°C) ad libitum during exercise (ICE), or precooled with iced towels and ice slurry ingestion (15g/kg) before drinking ice slurry ad libitum during exercise (PC+ICE). Power output, rectal temperature, and ratings of thermal comfort were measured.

Results:

Overall mean power output was possibly higher in ICE (+1.4% ± 1.8% [90% confidence limit]; 0.4 > smallest worthwhile change [SWC]) and likely higher PC+ICE (+2.5% ± 1.9%; 1.5 > SWC) than in CON; however, no substantial differences were shown between PC+ICE and ICE (unclear). Time-trial performance was likely enhanced in ICE compared with CON (+2.4% ± 2.7%; 1.4 > SWC) and PC+ICE (+2.9% ± 3.2%; 1.9 > SWC). Differences in mean rectal temperature during exercise were unclear between trials. Ratings of thermal comfort were likely and very likely lower during exercise in ICE and PC+ICE, respectively, than in CON.

Conclusions:

While PC+ICE had a stronger effect on mean power output compared with CON than ICE did, the ICE strategy enhanced late-stage time-trial performance the most. Findings suggest that thermal comfort may be as important as thermal state for maximizing performance in the heat.
Shoulder-Muscle Electromyography During Shoulder External-Rotation Exercises With and Without Slight Abduction
Authors: Sakita Kazuto , Seeley Matthew K. , Myrer Joseph William , Hopkins J. Ty
Published: January 2015

Context:

Standing and side-lying external-rotation exercises produce high activation of the deltoid and infraspinatus. Slight shoulder abduction during these exercises may decrease deltoid activity and increase infraspinatus activity.

Objective:

To determine if the addition of a towel under the arm during standing and side-lying external rotation affects infraspinatus, middle and posterior deltoid, and pectoralis major activation characteristics compared with a no-towel condition.

Design:

Controlled laboratory study.

Participants:

20 male volunteers (age 26 ± 3 y, height 1.80 ± 0.07 m, mass 77 ± 10 kg) who were right-hand dominant and had bilaterally healthy shoulders with no current cervical pathology and no skin infection or shoulder lesion.

Interventions:

External-rotation exercises without a towel roll (0° shoulder abduction) and with a towel roll (30° shoulder abduction) were performed in a standing and side-lying.

Main Outcome Measures:

Maximal voluntary isometric contraction for the infraspinatus, middle and posterior deltoid, and pectoralis major and external rotation in standing and side-lying with and without a towel roll were performed. Normalized average and peak surface EMG amplitude were compared between the towel conditions during standing and side-lying external rotation.

Results:

Both infraspinatus and pectoralis major activity had no significant differences between the towel conditions in standing and side-lying (P > .05). In standing and side-lying, posterior-deltoid activity was significantly greater with a towel roll (P < .05). Middle-deltoid activity had no significant differences between the towel conditions in standing (P > .05). However, in side-lying, middle-deltoid activity was significantly lower with a towel roll (P < .05).

Conclusion:

Middle-deltoid activity decreased with a towel roll during side-lying exercises. More data are needed to determine if a towel roll could be used to potentially reduce superior glide during external-rotation exercises.
Descriptive Analysis of Common Functional Limitations Identified by Patients With Shoulder Pain
Authors: Smith-Forbes Enrique V. , Moore-Reed Stephanie D. , Westgate Philip M. , Kibler W. Ben , Uhl Tim L.
Published: January 2015

Context:

Recent establishment of G-codes by the US government requires therapists to report function limitations at initial evaluation. Limited information exists specific to the most common limitations in patients with shoulder pain.

Objective:

To describe the most commonly expressed shoulder limitations with activities and their severity/level of impairment from a patient’s perspective on the initial evaluation.

Design:

Descriptive.

Setting:

Patients reporting pain with overhead activity and seeking medical attention from one orthopedic surgeon were recruited as part of a cohort study.

Patients:

176 with shoulder superior labral tear from anterior to posterior (SLAP), subacromial impingement, combined SLAP and rotator cuff, and nonspecific (female = 53, age = 41 ± 13 y; male = 123, age = 41 ± 12 y).

Interventions:

Data were obtained on the initial visit from the Patient-Specific Functional Scale (PSFS) questionnaire. Three researchers extracted meaningful concepts from the PSFS and linked them to the International Classification of Functioning (ICF) categories according to established ICF linking rules.

Results:

176 participants yielded 765 meaningful concepts that were linked to the ICF with a 66% agreement between researchers before consensus. There were no differences between diagnoses. Of all patients, 88% reported functional limitations coded into meaningful concepts as represented by 10 ICF codes; 634 (83%) meaningful concepts were linked to the activities and participation domain while 129 (17%) were linked to the body function domain. Only 2 reported functional limitations that were considered nondefinable (nd). The overall average initial impairment score on the PSFS = 4 ± 2.5 out of 10 points.

Conclusion:

Meaningful concepts from the activities and participation domain were most commonly identified as functional limitations and were more prevalent than limitations from the body function domain. This information helps identify some of the most common limitations in patients with shoulder pain that therapists can use to efficiently document patient functional impairment.
Effect of Salted Ice Bags on Surface and Intramuscular Tissue Cooling and Rewarming Rates
Authors: Hunter Eric J. , Ostrowski Jennifer , Donahue Matthew , Crowley Caitlyn , Herzog Valerie
Published: January 2015

Context:

Many researchers have investigated the effectiveness of different cryotherapy agents at decreasing intramuscular tissue temperatures. However, no one has looked at the effectiveness of adding salt to an ice bag.

Objective:

To compare the cooling effectiveness of different ice bags (wetted, salted cubed, and salted crushed) on cutaneous and intramuscular temperatures.

Design:

Repeated-measures counterbalanced design.

Setting:

University research laboratory.

Participants:

24 healthy participants (13 men, 11 women; age 22.46 ± 2.33 y, height 173.25 ± 9.78 cm, mass 74.51 ± 17.32 kg, subcutaneous thickness 0.63 ± 0.27 cm) with no lower-leg injuries, vascular diseases, sensitivity to cold, compromised circulation, or chronic use of NSAIDs.

Interventions:

Ice bags made of wetted ice (2000 mL ice and 300 mL water), salted cubed ice (intervention A; 2000 mL of cubed ice and 1/2 tablespoon of salt), and salted crushed ice (intervention B; 2000 mL of crushed ice and 1/2 tablespoon of salt) were applied to the posterior gastrocnemius for 30 min. Each participant received all conditions with at least 4 d between treatments.

Main Outcome Measure:

Cutaneous and intramuscular (2 cm plus adipose thickness) temperatures of nondominant gastrocnemius were measured during a 10-min baseline period, a 30-min treatment period, and a 45-min rewarming period.

Results:

Differences from baseline were observed for all treatments. The wetted-ice and salted-cubed-ice bags produced significantly lower intramuscular temperatures than the salted-crushed-ice bag. Wetted-ice bags produced the greatest temperature change for cutaneous tissues.

Conclusions:

Wetted- and salted-cubed-ice bags were equally effective at decreasing intramuscular temperature at 2 cm subadipose. Clinical practicality may favor salted-ice bags over wetted-ice bags.
Inherited landscapes and sea level change
Authors: Cloetingh Sierd , Haq Bilal U.
Published: January 2015

Volume and shape combine to find a level

How can we understand the geological record of sea level change? Sea level varies on time scales from decades to millions of years. These changes have local, regional, and global components and are caused by a wide variety of earth processes. Cloetingh and Haq review how the views of stratigraphers (who interpret the record of marine sediments) and geodynamicists (who consider changes in the shape of Earth caused by lithospheric and mantle processes) have begun to complement each other and are moving toward a more coherent interpretation of the history of sea level. They focus on cyclic sea-level changes 0.5 to 3.0 million years in duration that occurred in the Cretaceous period, approximately 145 to 65 million years ago.

Science
, this issue
10.1126/science.1258375
Hidden costs of infection: Chronic malaria accelerates telomere degradation and senescence in wild birds
Authors: Asghar M. , Hasselquist D. , Hansson B. , Zehtindjiev P. , Westerdahl H. , Bensch S.
Published: January 2015

Chronic malaria shortens telomeres

Chronic infections are assumed to cause little damage to the host, but is this true? Migrant birds can pick up various species of malaria parasite while overwintering in the tropics. After initial acute malaria, migrant great reed warblers, which nest in Sweden and overwinter in Africa, are asymptomatically infected for life. Asghar
et al.
discovered that these cryptically infected birds laid fewer eggs and were less successful at rearing healthy offspring than uninfected birds. Furthermore, infected birds had significantly shorter telomeres (the protective caps on the ends of chromosomes) and produced chicks with shortened telomeres.

Science
, this issue p.
436
A molecular census of 26
S
proteasomes in intact neurons
Authors: Asano Shoh , Fukuda Yoshiyuki , Beck Florian , Aufderheide Antje , Förster Friedrich , Danev Radostin , Baumeister Wolfgang
Published: January 2015

A detailed look at proteasomes in situ

The 26
S
proteasome is a protein machine that degrades intracellular proteins in the cytosol. The proteasome is critical for protein quality control and for the regulation of numerous cellular processes in eukaryotic cells. The structure of isolated proteasomes is well established, but how intact proteasomes look within the cell is less clear. Asano
et al.
used an improved approach to electron cryotomography to look at proteasomes in intact hippocampal neurons. Their analysis suggests that these cells only use about 20% of their proteasomes in an unstressed state, which leaves significant spare capacity to deal with proteotoxic stress.

Science
, this issue p.
439
The exceptionally powerful TeV γ-ray emitters in the Large Magellanic Cloud
Authors:   The H.E.S.S. Collaboration
Published: January 2015

A light on the origin of cosmic rays

There's a new lab for studying the origins of cosmic rays: our neighbor galaxy, the Large Magellanic Cloud. Astronomers are now making progress on this topic by examining the gamma rays that are produced when cosmic rays interact with gas or lower-energy photons. The H.E.S.S. Collaboration has detected three sources of gamma rays in a variety of forms in the galactic satellite to the Milky Way. The sources include the pulsar wind nebula of N 157B, the supernova remnant N 132D, and the superbubble 30 Dor C. Oddly, supernova 1987A was not detected.

Science
, this issue p.
406
Shock compression of stishovite and melting of silica at planetary interior conditions
Authors: Millot M. , Dubrovinskaia N. , Černok A. , Blaha S. , Dubrovinsky L. , Braun D. G. , Celliers P. M. , Collins G. W. , Eggert J. H. , Jeanloz R.
Published: January 2015

Melting silica in massive planets

To simulate the extreme conditions inside large planets requires extreme experiments. Millot
et al.
used high-pressure shock waves almost twice that of the center of Earth to melt silica, one of the primary components of planetary interiors. This was possible only by shocking a very dense form of silica called stishovite. Determining the melting point of silica is vital for developing better computational models of the interior of planets several times the mass of Earth. The high-pressure liquid was electrically conductive, a property that may contribute to magnetic dynamos in very large terrestrial exoplanets.

Science
, this issue p.
418
Tilt engineering of spontaneous polarization and magnetization above 300 K in a bulk layered perovskite
Authors: Pitcher Michael J. , Mandal Pranab , Dyer Matthew S. , Alaria Jonathan , Borisov Pavel , Niu Hongjun , Claridge John B. , Rosseinsky Matthew J.
Published: January 2015

Tilting toward two properties

Opposing electronic and symmetry constraints can make it difficult to combine some pairs of material properties in a single crystalline material. Magnetization and electrical polarization are such a pair, but their combination could be useful for applications such as magnetoelectric information storage. Pitcher
et al.
now show that careful design of chemical substitutions in a layered perovskite are both electrically polar and weakly ferromagnetic at temperatures up to 330 K.

Science
, this issue p.
420
Malaria may accelerate aging in birds
Authors: Vogel Gretchen
Published: January 2015

Infection erodes telomeres and life spans—hinting that there are no benign parasites.
Birth of a comet magnetosphere: A spring of water ions
Authors: Nilsson Hans , Stenberg Wieser Gabriella , Behar Etienne , Wedlund Cyril Simon , Gunell Herbert , Yamauchi Masatoshi , Lundin Rickard , Barabash Stas , Wieser Martin , Carr Chris , Cupido Emanuele , Burch James L. , Fedorov Andrei , Sauvaud Jean-André , Koskinen Hannu , Kallio Esa , Lebreton Jean-Pierre , Eriksson Anders , Edberg Niklas , Goldstein Raymond , Henri Pierre , Koenders Christoph , Mokashi Prachet , Nemeth Zoltan , Richter Ingo , Szego Karoly , Volwerk Martin , Vallat Claire , Rubin Martin
Published: January 2015

The Rosetta mission shall accompany comet 67P/Churyumov-Gerasimenko from a heliocentric distance of >3.6 astronomical units through perihelion passage at 1.25 astronomical units, spanning low and maximum activity levels. Initially, the solar wind permeates the thin comet atmosphere formed from sublimation, until the size and plasma pressure of the ionized atmosphere define its boundaries: A magnetosphere is born. Using the Rosetta Plasma Consortium ion composition analyzer, we trace the evolution from the first detection of water ions to when the atmosphere begins repelling the solar wind (~3.3 astronomical units), and we report the spatial structure of this early interaction. The near-comet water population comprises accelerated ions (<800 electron volts), produced upstream of Rosetta, and lower energy locally produced ions; we estimate the fluxes of both ion species and energetic neutral atoms.
The organic-rich surface of comet 67P/Churyumov-Gerasimenko as seen by VIRTIS/Rosetta
Authors: Capaccioni F. , Coradini A. , Filacchione G. , Erard S. , Arnold G. , Drossart P. , De Sanctis M. C. , Bockelee-Morvan D. , Capria M. T. , Tosi F. , Leyrat C. , Schmitt B. , Quirico E. , Cerroni P. , Mennella V. , Raponi A. , Ciarniello M. , McCord T. , Moroz L. , Palomba E. , Ammannito E. , Barucci M. A. , Bellucci G. , Benkhoff J. , Bibring J. P. , Blanco A. , Blecka M. , Carlson R. , Carsenty U. , Colangeli L. , Combes M. , Combi M. , Crovisier J. , Encrenaz T. , Federico C. , Fink U. , Fonti S. , Ip W. H. , Irwin P. , Jaumann R. , Kuehrt E. , Langevin Y. , Magni G. , Mottola S. , Orofino V. , Palumbo P. , Piccioni G. , Schade U. , Taylor F. , Tiphene D. , Tozzi G. P. , Beck P. , Biver N. , Bonal L. , Combe J.-Ph. , Despan D. , Flamini E. , Fornasier S. , Frigeri A. , Grassi D. , Gudipati M. , Longobardo A. , Markus K. , Merlin F. , Orosei R. , Rinaldi G. , Stephan K. , Cartacci M. , Cicchetti A. , Giuppi S. , Hello Y. , Henry F. , Jacquinod S. , Noschese R. , Peter G. , Politi R. , Reess J. M. , Semery A.
Published: January 2015

The VIRTIS (Visible, Infrared and Thermal Imaging Spectrometer) instrument on board the Rosetta spacecraft has provided evidence of carbon-bearing compounds on the nucleus of the comet 67P/Churyumov-Gerasimenko. The very low reflectance of the nucleus (normal albedo of 0.060 ± 0.003 at 0.55 micrometers), the spectral slopes in visible and infrared ranges (5 to 25 and 1.5 to 5% kÅ
−1
), and the broad absorption feature in the 2.9-to-3.6–micrometer range present across the entire illuminated surface are compatible with opaque minerals associated with nonvolatile organic macromolecular materials: a complex mixture of various types of carbon-hydrogen and/or oxygen-hydrogen chemical groups, with little contribution of nitrogen-hydrogen groups. In active areas, the changes in spectral slope and absorption feature width may suggest small amounts of water-ice. However, no ice-rich patches are observed, indicating a generally dehydrated nature for the surface currently illuminated by the Sun.
On the nucleus structure and activity of comet 67P/Churyumov-Gerasimenko
Authors: Sierks Holger , Barbieri Cesare , Lamy Philippe L. , Rodrigo Rafael , Koschny Detlef , Rickman Hans , Keller Horst Uwe , Agarwal Jessica , A’Hearn Michael F. , Angrilli Francesco , Auger Anne-Therese , Barucci M. Antonella , Bertaux Jean-Loup , Bertini Ivano , Besse Sebastien , Bodewits Dennis , Capanna Claire , Cremonese Gabriele , Da Deppo Vania , Davidsson Björn , Debei Stefano , De Cecco Mariolino , Ferri Francesca , Fornasier Sonia , Fulle Marco , Gaskell Robert , Giacomini Lorenza , Groussin Olivier , Gutierrez-Marques Pablo , Gutiérrez Pedro J. , Güttler Carsten , Hoekzema Nick , Hviid Stubbe F. , Ip Wing-Huen , Jorda Laurent , Knollenberg Jörg , Kovacs Gabor , Kramm J. Rainer , Kührt Ekkehard , Küppers Michael , La Forgia Fiorangela , Lara Luisa M. , Lazzarin Monica , Leyrat Cédric , Lopez Moreno Josè J. , Magrin Sara , Marchi Simone , Marzari Francesco , Massironi Matteo , Michalik Harald , Moissl Richard , Mottola Stefano , Naletto Giampiero , Oklay Nilda , Pajola Maurizio , Pertile Marco , Preusker Frank , Sabau Lola , Scholten Frank , Snodgrass Colin , Thomas Nicolas , Tubiana Cecilia , Vincent Jean-Baptiste , Wenzel Klaus-Peter , Zaccariotto Mirco , Pätzold Martin
Published: January 2015

Images from the OSIRIS scientific imaging system onboard Rosetta show that the nucleus of 67P/Churyumov-Gerasimenko consists of two lobes connected by a short neck. The nucleus has a bulk density less than half that of water. Activity at a distance from the Sun of >3 astronomical units is predominantly from the neck, where jets have been seen consistently. The nucleus rotates about the principal axis of momentum. The surface morphology suggests that the removal of larger volumes of material, possibly via explosive release of subsurface pressure or via creation of overhangs by sublimation, may be a major mass loss process. The shape raises the question of whether the two lobes represent a contact binary formed 4.5 billion years ago, or a single body where a gap has evolved via mass loss.
Play it again, SAM
Authors: Zahnle Kevin
Published: January 2015

Lasers shine new light on the drying of Mars while reviving the mystery of methane

[Also see Reports by

Mahaffy
et al.

and

Webster
et al.

]
Dust measurements in the coma of comet 67P/Churyumov-Gerasimenko inbound to the Sun
Authors: Rotundi Alessandra , Sierks Holger , Della Corte Vincenzo , Fulle Marco , Gutierrez Pedro J. , Lara Luisa , Barbieri Cesare , Lamy Philippe L. , Rodrigo Rafael , Koschny Detlef , Rickman Hans , Keller Horst Uwe , López-Moreno José J. , Accolla Mario , Agarwal Jessica , A’Hearn Michael F. , Altobelli Nicolas , Angrilli Francesco , Barucci M. Antonietta , Bertaux Jean-Loup , Bertini Ivano , Bodewits Dennis , Bussoletti Ezio , Colangeli Luigi , Cosi Massimo , Cremonese Gabriele , Crifo Jean-Francois , Da Deppo Vania , Davidsson Björn , Debei Stefano , De Cecco Mariolino , Esposito Francesca , Ferrari Marco , Fornasier Sonia , Giovane Frank , Gustafson Bo , Green Simon F. , Groussin Olivier , Grün Eberhard , Güttler Carsten , Herranz Miguel L. , Hviid Stubbe F. , Ip Wing , Ivanovski Stavro , Jerónimo José M. , Jorda Laurent , Knollenberg Joerg , Kramm Rainer , Kührt Ekkehard , Küppers Michael , Lazzarin Monica , Leese Mark R. , López-Jiménez Antonio C. , Lucarelli Francesca , Lowry Stephen C. , Marzari Francesco , Epifani Elena Mazzotta , McDonnell J. Anthony M. , Mennella Vito , Michalik Harald , Molina Antonio , Morales Rafael , Moreno Fernando , Mottola Stefano , Naletto Giampiero , Oklay Nilda , Ortiz José L. , Palomba Ernesto , Palumbo Pasquale , Perrin Jean-Marie , Rodríguez Julio , Sabau Lola , Snodgrass Colin , Sordini Roberto , Thomas Nicolas , Tubiana Cecilia , Vincent Jean-Baptiste , Weissman Paul , Wenzel Klaus-Peter , Zakharov Vladimir , Zarnecki John C.
Published: January 2015

Critical measurements for understanding accretion and the dust/gas ratio in the solar nebula, where planets were forming 4.5 billion years ago, are being obtained by the GIADA (Grain Impact Analyser and Dust Accumulator) experiment on the European Space Agency’s Rosetta spacecraft orbiting comet 67P/Churyumov-Gerasimenko. Between 3.6 and 3.4 astronomical units inbound, GIADA and OSIRIS (Optical, Spectroscopic, and Infrared Remote Imaging System) detected 35 outflowing grains of mass 10
−10
to 10
−7
kilograms, and 48 grains of mass 10
−5
to 10
−2
kilograms, respectively. Combined with gas data from the MIRO (Microwave Instrument for the Rosetta Orbiter) and ROSINA (Rosetta Orbiter Spectrometer for Ion and Neutral Analysis) instruments, we find a dust/gas mass ratio of 4 ± 2 averaged over the sunlit nucleus surface. A cloud of larger grains also encircles the nucleus in bound orbits from the previous perihelion. The largest orbiting clumps are meter-sized, confirming the dust/gas ratio of 3 inferred at perihelion from models of dust comae and trails.
Flexibility for specificity
Authors: Davis Mark M.
Published: January 2015

Human T cells show remarkable differentiation plasticity in responding to pathogens

[Also see Research Article by

Becattini
et al.

]
Vaccine Self-Assembling Immune Matrix Is a New Delivery Platform That Enhances Immune Responses to Recombinant HBsAg in Mice
Authors: Grenfell Rafaella F. Q. , Shollenberger Lisa M. , Samli E. Farah , Harn Donald A.
Published: January 2015

Vaccination remains the most effective public health tool to prevent infectious diseases. Many vaccines are marginally effective and need enhancement for immunocompromised, elderly, and very young populations. To enhance immunogenicity, we exploited the biphasic property of the (RADA)4 synthetic oligopeptide to create VacSIM (vaccine self-assembling immune matrix), a new delivery method. VacSIM solution can easily be mixed with antigens, organisms, and adjuvants for injection. Postinjection, the peptides self-assemble into hydrated nanofiber gel matrices, forming a depot with antigens and adjuvants in the aqueous phase. We believe the depot provides slow release of immunogens, leading to increased activation of antigen-presenting cells that then drive enhanced immunogenicity. Using recombinant hepatitis B virus surface antigen (rHBsAg) as a model immunogen, we compared VacSIM delivery to delivery in alum or complete Freund's adjuvant (CFA). Delivery of the rHBsAg antigen to mice via VacSIM without adjuvant elicited higher specific IgG responses than when rHBsAg was delivered in alum or CFA. Evaluating IgG subtypes showed a mixed Th1/Th2 type response following immunization with VacSIM, which was driven further toward Th1 with addition of CpG as the adjuvant. Increased specific IgG endpoint titers were observed in both C57BL/6 and BALB/c mice, representative of Th1 and Th2 environments, respectively. Restimulation of splenocytes suggests that VacSIM does not cause an immediate proinflammatory response in the host. Overall, these results suggest that VacSIM, as a new delivery method, has the potential to enhance immunogenicity and efficacy of numerous vaccines.
Discordance between Xpert MTB/RIF Assay and Bactec MGIT 960 Culture System for Detection of Rifampin-Resistant Mycobacterium tuberculosis Isolates in a Country with a Low Tuberculosis (TB) Incidence
Authors: Mokaddas Eiman , Ahmad Suhail , Eldeen Hanaa S. , Al-Mutairi Noura
Published: January 2015

Among 452 samples that were positive by the Xpert MTB/RIF (Xpert) assay and MGIT 960 system (MGIT), 440 and 10Mycobacterium tuberculosissamples were detected as rifampin susceptible and rifampin resistant, respectively. Two isolates that were rifampin susceptible by the MGIT system were rifampin resistant by the Xpert assay.rpoBsequencing identified a silent (CTG521TTG) mutation in one isolate and a missense (GAC516TAC) mutation in another. The detection of rifampin resistance is imperfect with both the Xpert assay and MGIT system. Any discordant rifampin resistance results should be confirmed by sequencing of therpoBgene.
Soluble T Cell Immunoglobulin Mucin Domain 3 Is Shed from CD8
+
T Cells by the Sheddase ADAM10, Is Increased in Plasma during Untreated HIV Infection, and Correlates with HIV Disease Progression
Authors: Clayton Kiera L. , Douglas-Vail Matthew B. , Rahman A. K. M. Nur-ur , Medcalf Karyn E. , Xie Irene Y. , Chew Glen M. , Tandon Ravi , Lanteri Marion C. , Norris Philip J. , Deeks Steven G. , Ndhlovu Lishomwa C. , Ostrowski Mario A.
Published: January 2015

Chronic HIV infection results in a loss of HIV-specific CD8
+
T cell effector function, termed “exhaustion,” which is mediated, in part, by the membrane coinhibitory receptor T cell immunoglobulin mucin domain-3 (Tim-3). Like many other receptors, a soluble form of this protein has been described in human blood plasma. However, soluble Tim-3 (sTim-3) is poorly characterized, and its role in HIV disease is unknown. Here, we show that Tim-3 is shed from the surface of responding CD8
+
T cells by the matrix metalloproteinase ADAM10, producing a soluble form of the coinhibitory receptor. Despite previous reports in the mouse model, no alternatively spliced, soluble form of Tim-3 was observed in humans. Shed sTim-3 was found in human plasma and was significantly elevated during early and chronic untreated HIV infection, but it was not found differentially modulated in highly active antiretroviral therapy (HAART)-treated HIV-infected subjects or in elite controllers compared to HIV-uninfected subjects. Plasma sTim-3 levels were positively correlated with HIV load and negatively correlated with CD4 counts. Thus, plasma sTim-3 shedding correlated with HIV disease progression. Despite these correlations, we found that shedding Tim-3 did not improve the function of CD8
+
T cells in terms of gamma interferon production or prevent their apoptosis through galectin-9. Further characterization studies of sTim-3 function are needed to understand the contribution of sTim-3 in HIV disease pathogenesis, with implications for novel therapeutic interventions.

IMPORTANCE
Despite the overall success of HAART in slowing the progression to AIDS in HIV-infected subjects, chronic immune activation and T cell exhaustion contribute to the eventual deterioration of the immune system. Understanding these processes will aid in the development of interventions and therapeutics to be used in combination with HAART to slow or reverse this deterioration. Here, we show that a soluble form of T cell exhaustion associated coinhibitory molecule 3, sTim-3, is shed from the surface of T cells. Furthermore, sTim-3 is elevated in the plasma of treatment-naive subjects with acute or chronic HIV infection and is associated with markers of disease progression. This is the first study to characterize sTim-3 in human plasma, its source, and mechanism of production. While it is still unclear whether sTim-3 contributes to HIV pathogenesis, sTim-3 may represent a new correlate of HIV disease progression.
Modulation of a Pore in the Capsid of JC Polyomavirus Reduces Infectivity and Prevents Exposure of the Minor Capsid Proteins
Authors: Nelson Christian D. S. , Ströh Luisa J. , Gee Gretchen V. , O'Hara Bethany A. , Stehle Thilo , Atwood Walter J.
Published: January 2015

JC polyomavirus (JCPyV) infection of immunocompromised individuals results in the fatal demyelinating disease progressive multifocal leukoencephalopathy (PML). The viral capsid of JCPyV is composed primarily of the major capsid protein virus protein 1 (VP1), and pentameric arrangement of VP1 monomers results in the formation of a pore at the 5-fold axis of symmetry. While the presence of this pore is conserved among polyomaviruses, its functional role in infection or assembly is unknown. Here, we investigate the role of the 5-fold pore in assembly and infection of JCPyV by generating a panel of mutant viruses containing amino acid substitutions of the residues lining this pore. Multicycle growth assays demonstrated that the fitness of all mutants was reduced compared to that of the wild-type virus. Bacterial expression of VP1 pentamers containing substitutions to residues lining the 5-fold pore did not affect pentamer assembly or prevent association with the VP2 minor capsid protein. The X-ray crystal structures of selected pore mutants contained subtle changes to the 5-fold pore, and no other changes to VP1 were observed. Pore mutant pseudoviruses were not deficient in assembly, packaging of the minor capsid proteins, or binding to cells or in transport to the host cell endoplasmic reticulum. Instead, these mutant viruses were unable to expose VP2 upon arrival to the endoplasmic reticulum, a step that is critical for infection. This study demonstrated that the 5-fold pore is an important structural feature of JCPyV and that minor modifications to this structure have significant impacts on infectious entry.

IMPORTANCE
JCPyV is an important human pathogen that causes a severe neurological disease in immunocompromised individuals. While the high-resolution X-ray structure of the major capsid protein of JCPyV has been solved, the importance of a major structural feature of the capsid, the 5-fold pore, remains poorly understood. This pore is conserved across polyomaviruses and suggests either that these viruses have limited structural plasticity in this region or that this pore is important in infection or assembly. Using a structure-guided mutational approach, we showed that modulation of this pore severely inhibits JCPyV infection. These mutants do not appear deficient in assembly or early steps in infectious entry and are instead reduced in their ability to expose a minor capsid protein in the host cell endoplasmic reticulum. Our work demonstrates that the 5-fold pore is an important structural feature for JCPyV.
Narrowing of Human Influenza A Virus-Specific T Cell Receptor α and β Repertoires with Increasing Age
Authors: Gil Anna , Yassai Maryam B. , Naumov Yuri N. , Selin Liisa K.
Published: January 2015

Alterations in memory CD8 T cell responses may contribute to the high morbidity and mortality caused by seasonal influenza A virus (IAV) infections in older individuals. We questioned whether memory CD8 responses to this nonpersistent virus, to which recurrent exposure with new strains is common, changed over time with increasing age. Here, we show a direct correlation between increasing age and narrowing of the HLA-A2-restricted IAV Vα and Vβ T cell repertoires specific to M1 residues 58 to 66 (M1
58–66
), which simultaneously lead to oligoclonal expansions, including the usage of a single identical VA12-JA29 clonotype in all eight older donors. The Vα repertoire of older individuals also had longer CDR3 regions with increased usage of G/A runs, whose molecular flexibility may enhance T cell receptor (TCR) promiscuity. Collectively, these results suggest that CD8 memory T cell responses to nonpersistent viruses like IAV in humans are dynamic, and with aging there is a reduced diversity but a preferential retention of T cell repertoires with features of enhanced cross-reactivity.

IMPORTANCE
With increasing age, the immune system undergoes drastic changes, and older individuals have declined resistance to infections. Vaccinations become less effective, and infection with influenza A virus in older individuals is associated with higher morbidity and mortality. Here, we questioned whether T cell responses directed against the highly conserved HLA-A2-restricted M1
58–66
peptide of IAV evolves with increasing age. Specifically, we postulated that CD8 T cell repertoires narrow with recurrent exposure and may thus be less efficient in response to new infections with new strains of IAV. Detailed analyses of the VA and VB TCR repertoires simultaneously showed a direct correlation between increasing age and narrowing of the TCR repertoire. Features of the TCRs indicated potentially enhanced cross-reactivity in all older donors. In summary, T cell repertoire analysis in older individuals may be useful as one of the predictors of protection after vaccination.
Transmission Properties of Atypical Creutzfeldt-Jakob Disease: a Clue to Disease Etiology?
Authors: Kobayashi Atsushi , Parchi Piero , Yamada Masahito , Brown Paul , Saverioni Daniela , Matsuura Yuichi , Takeuchi Atsuko , Mohri Shirou , Kitamoto Tetsuyuki
Published: January 2015

The genotype at polymorphic codon 129 of the
PRNP
gene has a profound influence on both phenotypic expression and prion strain susceptibility in humans. For example, while the most common sporadic Creutzfeldt-Jakob disease (CJD) subtype, sporadic CJD-MM1 (M1 strain), induces a single phenotype after experimental transmission regardless of the codon 129 genotype of the recipient animal, the phenotype elicited by sporadic CJD-VV2 (V2 strain), the second most common subtype, varies according to the host codon 129 genotype. In particular, the propagation of the V2 strain in codon 129 methionine homozygotes has been linked only to acquired forms of CJD such as plaque-type dura mater graft-associated CJD (dCJD), a subgroup of iatrogenic CJD with distinctive phenotypic features, but has never been observed in sporadic CJD cases. In the present report, we describe atypical CJD cases carrying codon 129 methionine homozygosity, in a neurosurgeon and in a patient with a medical history of neurosurgery without dural grafting, showing the distinctive phenotypic features and transmission properties of plaque-type dCJD. These findings raise the possibility that the two cases, previously thought to represent sporadic CJD, might actually represent acquired CJD caused by infection with the V2 strain. Thus, careful analyses of phenotypic features and transmission properties in atypical cases may be useful to distinguish acquired from sporadic cases of CJD.

IMPORTANCE
Susceptibility to and phenotypic expression of Creutzfeldt-Jakob disease (CJD) depend on both the prion strain and genotype at polymorphic codon 129 of the
PRNP
gene. For example, propagation of the second most common sporadic CJD strain (V2 strain) into codon 129 methionine homozygotes has been linked to plaque-type dura mater graft-associated CJD (dCJD), a subgroup of iatrogenic CJD with distinctive phenotypic features, but has never been observed in sporadic CJD. In the present report, we describe atypical CJD cases in a neurosurgeon and in a patient with a medical history of neurosurgery without dural grafting, showing the distinctive phenotypic features and transmission properties of plaque-type dCJD. These findings raise the possibility that the two cases, previously considered to represent sporadic CJD, might actually represent acquired CJD caused by infection with the V2 strain.
The Susceptibility of Primate Lentiviruses to Nucleosides and Vpx during Infection of Dendritic Cells Is Regulated by CA
Authors: Barateau Véronique , Nguyen Xuan-Nhi , Bourguillault Fanny , Berger Grégory , Cordeil Stéphanie , Cimarelli Andrea
Published: January 2015

The block toward human immunodeficiency virus type 1 (HIV-1) infection of dendritic cells (DCs) can be relieved by Vpx (viral protein X), which degrades sterile alpha motif-hydroxylase domain 1 (SAMHD1) or by exogenously added deoxynucleosides (dNs), lending support to the hypothesis that SAMHD1 acts by limiting deoxynucleoside triphosphates (dNTPs). This notion has, however, been questioned. We show that while dNs and Vpx increase the infectivity of HIV-1, only the latter restores the infectivity of a simian immunodeficiency virus of macaques variant, SIV
MAC
ΔVpx virus. This distinct behavior seems to map to CA, suggesting that species-specific CA interactors modulate infection of DCs.
Essential medicines for children
Authors: Hoppu Kalle , Sri Ranganathan Shalini
Published: January 2015

Millions of children die every year before they reach the age of 5 years, of conditions largely treatable with existing medicines. The WHO Model List of Essential Medicines was launched in 1977 to make the most necessary drugs available to populations whose basic health needs could not be met by the existing supply system. During the first 30 years of the Model List of Essential Medicines, children's needs were not systematically considered. After adoption of the ‘Better medicines for children’ resolution by the World Health Assembly, things changed. The first WHO Model List of Essential Medicines for Children was drawn up by a Paediatric Expert Subcommittee and adopted in October 2007. The most recent, 4th Model List of Essential Medicines for Children was adopted in 2013. Data from country surveys show that access to essential medicines for children is still generally poor; much more work is needed.
An index for quantifying female education and child health in emerging economies
Authors: Rodríguez Martín José Antonio , Holgado Molina María del Mar , Salinas Fernández José Antonio
Published: January 2015

Objective

To construct an index to measure female education and child health in the least developed countries (LDCs) of Asia.

Methods and results

The design of our index includes the variables of female education and child health defined in the goals of the Millennium Declaration. For this purpose, we used Pena's P2distance method for 2011, the last year for which data were available for the set of variables.

Conclusion

We have proposed a territorial measure and classification of female education and child health in the LDCs of Asia. We believe that the most striking differences between countries relate to basic female education variables such as girls’ primary completion rate, and female literacy.
4D flow preliminary investigation of a direct carotid cavernous fistula due to a ruptured intracavernous aneurysm
Authors: Nakagawa Shunsuke , Murai Yasuo , Wada Takeshi , Tateyama Kojiro
Published: January 2015

Inadequate information is available about the cerebral blood flow and surgical strategies of a direct aneurysmal carotid cavernous fistula (daCCF). We report a quantitative analysis of flow velocity and volume using preoperative time-resolved phase-contrast MRI (four-dimensional (4D) flow MRI) in a daCCF. This is the first report of 4D flow findings with a daCCF. A 55-year-old woman developed a sudden headache and bruit of the right orbit, and MRI suggested the presence of a daCCF. Quantitative analysis using preoperative 4D flow MRI revealed the flow volume of the right internal carotid artery. The daCCF was successfully treated by high-flow bypass using a radial artery graft and internal carotid artery trapping. Postoperative angiography showed a complete obliteration of the daCCF. Studies to collect data from additional cases are required so that 4D flow findings can be further used in the management of daCCFs.
Abdominal cocoon: idiopathic sclerosing encapsulating peritonitis
Authors: Frost Jason H , Price Elizabeth E
Published: January 2015

Abdominal cocoon, or idiopathic sclerosing encapsulating peritonitis, is a rare condition characterised by the presence of a dense fibrocollagenous membrane partially or totally encapsulating the small bowel leading to recurrent intestinal obstructions. We present the case of a patient who has presented for the fourth time with a small bowel obstruction. Previous laparoscopy revealed a plaque-like reactive process encapsulating much of the small bowel and the liver. After initial adhesiolysis, the patient's obstructions continued to reoccur. Further laparotomy was performed in order to excise the entirety of the cocoon membrane and free up loops of small bowel encapsulated by the process, hopefully preventing future obstructions.
Veterinary practice marketeer
Authors: Phillips Justin
Published: January 2015

Justin Phillips is marketing manager at White Cross Vets and the Veterinary Marketing Association's (VMA's) Young Veterinary Marketeer of the Year. Here, he describes what he does and why he believes other practices should embrace marketing to improve their quality and client care
Diary of a poultry intern
Authors: Garton William
Published: January 2015

Christmas is a demanding time for vets working in the poultry industry. As the memory of the season fades, William Garton reflects on his initial four months as a poultry intern.