bluuebunny/crossref_metadata_2025 huggingface dataset:
Poroelastic Loading of an Aquifer Due to Upstream Dam Releases
Authors: Boutt David F.
Published: January 2010

Short‐term changes in the hydraulic head of surface water bodies are known to influence the shallow response of hydraulically connected groundwaters. Associated with these fluctuations is the physical increase in stream water creating a mechanical load on the ground surface. This load is supported by the geologic materials (sediment or rock) and the pore fluid contained within the pores. Changes in this surface load have a direct effect on the total stress of the aquifer causing either a change in effective stress or fluid pressure. This response, predicted by the framework of linear poroelasticity, is a well‐understood phenomenon in geologic materials. Currently, field measurements of the hydraulic response (i.e., fluid pressure) of aquifer materials are undergoing poroelastic loading due to dam releases in the Deerfield River Watershed in Massachusetts. An increase in stream stage from upstream dam releases causes an instantaneous pore fluid pressure increase at multiple depths and locations in the aquifer. This increase lasts anywhere from 15 to 40 minutes depending on the magnitude of the rise in the stream stage. Pore‐pressure changes are well correlated to stream stage fluctuations for all of the recorded events. Poroelastic models created using basin stratigraphy and hydraulic properties of the aquifer response match the field observations well. Model results suggest that the overall stratigraphy is important in controlling the magnitude and duration of the poroelastic response. An improved understanding of responses such as these can be used to constrain uncertainties in model calibration and simulations of the contaminant migration in low permeability fine‐grained (compressive) materials.
Arsenic Management Through Well Modification and Simulation
Authors: Halford Keith J. , Stamos Christina L. , Nishikawa Tracy , Martin Peter
Published: January 2010

Arsenic concentrations can be managed with a relatively simple strategy of grouting instead of completely destroying a selected interval of well. The strategy of selective grouting was investigated in Antelope Valley, California, where groundwater supplies most of the water demand. Naturally occurring arsenic typically exceeds concentrations of 10 µg/L in the water produced from these long‐screened wells. The vertical distributions of arsenic concentrations in intervals of the aquifer contributing water to selected supply wells were characterized with depth‐dependent water‐quality sampling and flow logs. Arsenic primarily entered the lower half of the wells where lacustrine clay deposits and a deeper aquifer occurred. Five wells were modified by grouting from below the top of the lacustrine clay deposits to the bottom of the well, which reduced produced arsenic concentrations to less than 2 µg/L in four of the five wells. Long‐term viability of well modification and reduction of specific capacity was assessed for well 4‐54 with AnalyzeHOLE, which creates and uses axisymmetric, radial MODFLOW models. Two radial models were calibrated to observed borehole flows, drawdowns, and transmissivity by estimating hydraulic‐conductivity values in the aquifer system and gravel packs of the original and modified wells. Lithology also constrained hydraulic‐conductivity estimates as regularization observations. Well encrustations caused as much as 2 µg/L increase in simulated arsenic concentration by reducing the contribution of flow from the aquifer system above the lacustrine clay deposits. Simulated arsenic concentrations in the modified well remained less than 3 µg/L over a 20‐year period.
Estimation of Degradation Rates by Satisfying Mass Balance at the Inlet
Authors: Batu Vedat
Published: January 2010

Using a steady‐state mass conservative solute transport analytical solution that is based on the third‐type (or flux‐type or Cauchy) source condition, a method is developed to estimate the degradation parameters of solutes in groundwater. Then, the inadequacy of the methods based on the first‐type source‐based analytical solute transport solution is presented both theoretically and through an example. It is shown that the third‐type source analytical solution exactly satisfies the mass balance constraint at the inlet location. It is also shown that the first‐type source (or constant source concentration or Dirichlet) solution fails to satisfy the mass balance constraint at the inlet location and the degree of the failure depends on the value of the degradation as well as the flow and solute transport parameters. The error in the first‐type source solution is determined with dimensionless parameters by comparing its results with the third‐type source solution. Methods for estimating the degradation parameter values that are based on the first‐type steady‐state solute transport solution may significantly overestimate the degradation parameter values depending on the values of flow and solute transport parameters. It is recommended that the third‐type source solution be used in estimating degradation parameters using measured concentrations instead of the first‐type source solution.
Seasonal Variation in Measured Solar Ultraviolet Radiation Exposure of Adults in Subtropical Australia
Authors: Neale Rachel E. , Hamilton Abbey R. , Janda Monika , Gies Peter , Green Adele C.
Published: January 2010

Generating accurate population‐specific public health messages regarding sun protection requires knowledge about seasonal variation in sun exposure in different environments. To address this issue for a subtropical area of Australia, we used polysulphone badges to measure UVR for the township of Nambour (26° latitude) and personal UVR exposure among Nambour residents who were taking part in a skin cancer prevention trial. Badges were worn by participants for two winter and two summer days. The ambient UVR was approximately three times as high in summer as in winter. However, participants received more than twice the proportion of available UVR in winter as in summer (6.5%vs 2.7%, P < 0.05), resulting in an average ratio of summer to winter personal UVR exposure of 1.35. The average absolute difference in daily dose between summer and winter was only one‐seventh of a minimal erythemal dose. Extrapolating from our data, we estimate that ca. 42% of the total exposure received in the 6 months of winter (June–August) and summer (December–February) is received during the three winter months. Our data show that in Queensland a substantial proportion of people’s annual UVR dose is obtained in winter, underscoring the need for dissemination of sun protection messages throughout the year in subtropical and tropical climates.
Does A1c consistently reflect mean plasma glucose?
Authors: SHROM David , SARWAT Samiha , ILAG Liza , BLOOMGARDEN Zachary T.
Published: January 2010

Background:  A1c, a surrogate measure of glycemic control, is known to have a strong linear correlation with mean plasma glucose (MPG) when analyzed in populations of patients. However, clinically significant intersubject variability in this relationship exists, which suggests that A1c measurements may not reflect actual glycemic control in some patients. In the present study we explored the extent to which A1c accurately represents glycemic control, as measured by MPG, for individual patients.

Methods:  Data were pooled from randomized clinical trials in which A1c and self‐monitored plasma glucose (SMPG) profiles were collected by patients with Type 2 diabetes treated with insulin analog regimens. MPG levels were calculated from SMPG profiles. Distributions of MPG were analyzed for patients within similar ranges of A1c (<6.5%, 6.5%–<7.5%, 7.5%–<8.5%, 8.5%–<9.5%, and ≥9.5%) and distributions of A1c were analyzed in patients within similar ranges of MPG (<6.1, 6.1–<7.8, 7.8–<9.4, 9.4–<11.1, and ≥11.1 mmol/L).

Results:  Substantial proportions of patients had clinically significant differences between A1c and MPG. For example, among 260 patients with A1c between 6.5% and 7.5%, 10% had MPG levels <6.4 mmol/L, whereas 10% had MPG >9.5 mmol/L. Among the 224 patients with MPG levels ≥6.1 mmol/L and <7.8 mmol/L, 10% had A1c <6% and 10% had A1c >8.1%.

Conclusions:  In the absence of SMPG, A1c may inadequately represent glycemic control for many diabetic patients.
Tumour necrosis factor inhibitors and risk of serious infection in rheumatoid arthritis
Authors: KATIKIREDDI Veera S. , WHITTLE Samuel L. , HILL Catherine L.
Published: January 2010

Tumour necrosis factor inhibitors have demonstrated significant clinical and radiological benefits in rheumatoid arthritis (RA). However, they have important adverse effects including an association with infection. Results from current studies, including meta‐analyses of randomized controlled trials and observational studies, are conflicting regarding the risk of serious infection in RA patients treated with TNF inhibitors. The majority of data suggest an increased risk, in particular of respiratory, skin and soft tissue infections, including tuberculosis. This increased risk of tuberculosis is of particular concern in the APLAR region. However, adverse event analysis remains a difficult area to study and decisions regarding initiation of TNF inhibitors must be made on a case‐by‐case basis after carefully considering the risks and benefits.
Rethinking the Work–Life Interface: It's Not about Balance, It's about Resource Allocation
Authors: Grawitch Matthew J. , Barber Larissa K. , Justice Logan
Published: January 2010

This article re‐conceptualises the framework surrounding work–life balance. Though previous research has focused primarily on the ways in which work life and non‐work life influence each other (mostly negatively), we present an alternative perspective that focuses on personal pursuits and the management of personal resources. We introduce a personal resource allocation (PRA) framework that treats all life demands—whether preferred or required—as forcing individuals to make choices about where, when, and how they expend their personal resources across the life domain. Building on self‐regulatory theories, such as control theory, self‐determination theory, and conservation of resources theory, we suggest ways in which effective personal resource allocation not only decreases negative outcomes (which has been the emphasis in work–life balance research), but also how effective personal resource allocation can actually contribute to positive outcomes. We conclude by providing some practical implications for individuals and organisations based on the PRA framework and suggest future research opportunities.
Evaluation of a Program on Systematic Self‐Monitoring and Reflection of Health Behavior in Organisations: Results of Two Randomised Controlled Studies on Well‐Being and Absenteeism of Employees and Skilled Workers
Authors: Krampen Günter
Published: January 2010

Effects of a group health promotion program on well‐being and absenteeism of employees and skilled workers were tested. The objectives of the program are systematic self‐monitoring and reflection on everyday life health behavior as well as the promotion of health‐ and development‐related cognitions and well‐being. Randomised group designs were employed to evaluate the program's effects on well‐being, psychosomatic complaints, personal regulation of own development, and absenteeism. Program effects were confirmed with reference to these outcome measures administered at the end of the 8‐week treatment and at 2‐month follow‐up in samples of 56 public employees (Study 1) and 39 skilled workers (Study 2). Results demonstrate the effectiveness and usability of the SySeRe program as an economical individual‐level health promotion intervention in occupational health psychology with large effect sizes in psychometric measures of well‐being and in the reduction of employee sick leave as well.
Interaction between Vibrio mimicus and Acanthamoeba castellanii
Authors: Abd Hadi , Valeru Soni Priya , Sami Susan Marouf , Saeed Amir , Raychaudhuri Saumya , Sandström Gunnar
Published: January 2010

Vibrio mimicus is a Gram‐negative bacterium, which causes gastroenteritis and is closely related to Vibrio cholerae. The environmental reservoir of this bacterium is far from defined. Acanthamoeba as well as Vibrio species are found in diverse aquatic environments. The present study was aimed to investigate the ability of A. castellanii to host V. mimicus, the role of bacterial protease on interaction with A. castellanii and to disclose the ability of cysts to protect intracellular V. mimicus. Co‐cultivation, viable counts, gentamicin assay, electron microscopy and statistical analysis showed that co‐cultivation of wild type and luxO mutant of V. mimicus strains with A. castellanii did not inhibit growth of the amoeba. On the other hand co‐cultivation enhanced growth and survival of V. mimicus strains. Vibrio mimicus showed intracellular behaviour because bacteria were found to be localized in the cytoplasm of amoeba trophozoites and remain viable for 14 days. The cysts protected intracellular V. mimicus from high level of gentamicin. The intracellular growth of V. mimicus in A. castellanii suggests a role of A. castellanii as a host for V. mimicus.
Uneven frequency of Vibrio alginolyticus‐group isolates among different populations of Galápagos marine iguana (Amblyrhynchus cristatus)
Authors: Thaller Maria C. , Ciambotta Marco , Sapochetti Manuela , Migliore Luciana , Tapia Whashington , Cedeño Virna , Gentile Gabriele
Published: January 2010

The presence of Vibrio isolates was investigated in cloacal swabs from the Galápagos marine iguana (Amblyrhyncus cristatus). Such unique iguana is endemic to the Galápagos Archipelago, it is listed as vulnerable in the IUCN Red List (2009), and is strictly protected by CITES and Ecuador laws. Our results revealed an uneven isolation frequency of vibrios from animals living in different settings: maximal among the Santa Fe population, scarce at Bahía Tortuga but practically absent in the samples from Puerto Ayora and Plaza Sur. A 16S sequencing confirmed that the isolates belonged to the genus Vibrio, placing them within the V. alginolyticus group; the biochemical identification was, indeed, consistent with V. alginolyticus features. The reason of the observed discrepancy is not clear, but could be either linked to a higher pollution in the inhabited or more touristic places or to differential influence of chemical and physical parameters at a local scale. As V. alginolyticus is an opportunistic pathogen for man and it is known to cause disease in sea‐living animals, the ability of these vibrios to enter and persist to a certain extent in the marine iguana gut should be regarded as a risk for health of both the animals and the human personnel involved in monitoring activities.
Neuropathy induced by exogenously administered advanced glycation end‐products in rats
Authors: Nishizawa Yusuke , Wada Ryu‐ichi , Baba Masayuki , Takeuchi Masayoshi , Hanyu‐Itabashi Chieko , Yagihashi Soroku
Published: January 2010

Aims/Introduction:  Advanced glycation end‐products (AGE) have been implicated in the development of diabetic neuropathy. It still remains unknown, however, how AGE cause functional and structural changes of the peripheral nerve in diabetes. To explore the role of AGE in diabetic neuropathy, we examined the peripheral nerve by injecting AGE into normal Wistar rats.

Materials and Methods:  Young, normal male Wistar rats were injected intraperitoneally (i.p.) daily for 12 weeks with purified AGE prepared by incubating D‐glucose with bovine serum albumin (BSA). A control group received BSA alone. A group of rats given AGE were co‐treated with aminoguanidine (50 mg/kg/day, i.p.). Peripheral nerve function and structure, as well as nerve Na+,K+‐ATPase activity, were examined in these rats. Immunohistochemical expressions of 8‐hydroxy‐2′‐deoxyguanosine (8OHdG) and nuclear factor‐κB (NF‐κB)p65 were also examined.

Results:  Serum AGE levels were increased two to threefold in the AGE‐treated group compared with those in the BSA‐treated control group. AGE‐treated rats showed a marked slowing of motor nerve conduction velocity (MNCV) and decreased nerve Na+,K+‐ATPase activity compared with those in the BSA‐treated group. These changes were accompanied by intensified expressions of 8OHdG and NF‐κBp65 in endothelial cells and Schwann cells. Aminoguanidine treatment corrected MNCV delay, Na+,K+‐ATPase activity, and suppressed the expression of 8OHdG and NF‐κB, despite there being no influence on serum AGE levels.

Conclusions:  The results suggest that an elevated concentration of blood AGE might be one of the contributing factors to the development of neuropathic changes in diabetes.
A Review of Surface Roughness Effects in Gas Turbines
Authors: Bons J. P.
Published: January 2010

The effects of surface roughness on gas turbine performance are reviewed based on publications in the open literature over the past 60 years. Empirical roughness correlations routinely employed for drag and heat transfer estimates are summarized and found wanting. No single correlation appears to capture all of the relevant physics for both engineered and service-related (e.g., wear or environmentally induced) roughness. Roughness influences engine performance by causing earlier boundary layer transition, increased boundary layer momentum loss (i.e., thickness), and/or flow separation. Roughness effects in the compressor and turbine are dependent on Reynolds number, roughness size, and to a lesser extent Mach number. At low Re, roughness can eliminate laminar separation bubbles (thus reducing loss) while at high Re (when the boundary layer is already turbulent), roughness can thicken the boundary layer to the point of separation (thus increasing loss). In the turbine, roughness has the added effect of augmenting convective heat transfer. While this is desirable in an internal turbine coolant channel, it is clearly undesirable on the external turbine surface. Recent advances in roughness modeling for computational fluid dynamics are also reviewed. The conclusion remains that considerable research is yet necessary to fully understand the role of roughness in gas turbines.
Adjoint Aerodynamic Design Optimization for Blades in Multistage Turbomachines—Part II: Validation and Application
Authors: Wang D. X. , He L. , Li Y. S. , Wells R. G.
Published: January 2010

This is the second part of a two-part paper. First, the design-optimization system based on the adjoint gradient solution approach as described in Part I is introduced. Several test cases are studied for further validation and demonstration of the methodology and implementation. The base-line adjoint method as applied to realistic 3D configurations is demonstrated in the redesign of the NASA rotor 67 at a near-choke condition, leading to a 1.77% efficiency gain. The proposed adjoint mixing plane is applied to the redesign of a transonic compressor stage (DLR compressor stage) and an IGV-rotor-stator configuration of a Siemens industrial compressor at a single-operating point, both producing measurably positive efficiency gains. An examination on the choice of the operating mass flow condition as the basis for the performance optimization, however, highlights the limitation of the single-point approach for practical applications. For the three-row compressor configuration, a near peak-efficiency point based redesign leads to a measurable reduction in the choke mass flow, while a near-choke point based redesign leads to a significant performance drop in other flow conditions. Subsequently, a parallel multipoint approach is implemented. The results show that a two-point design optimization can produce a consistently better performance over a whole range of mass flow conditions compared with the original design. In the final case, the effectiveness of the present method and system is demonstrated by a redesign applied to a seven-row industrial compressor at the design point, leading to a remarkable 2.4% efficiency gain.
Improvement of Stalling Characteristics of an Axial-Flow Fan by Radial-Vaned Air-Separators
Authors: Yamaguchi Nobuyuki , Ogata Masayuki , Kato Yohei
Published: January 2010

An improved construction of air-separator device, which has radial-vanes embedded within its inlet circumferential opening with their leading-edges facing the moving tips of the fan rotor-blades so as to scoop the tip flow, was investigated with respect to the stall-prevention effect on a low-speed, single-stage, lightly loaded, axial-flow fan. Stall-prevention effects by the separator layout, relative location of the separator to the rotor-blades, and widths of the openings of the air-separator inlet and exit were parametrically surveyed. As far as the particular fan is concerned, the device together with the best relative location has proved to be able to eliminate effectively the stall zone having existed in the original solid-wall characteristics, which has confirmed the promising potential of the device. Guidelines were obtained from the data for optimizing relative locations of the device to the rotor-blades, maximizing the stall-prevention effect of the device, and minimizing the axial size of the device for a required stall-prevention effect, at least for the particular fan and possibly for fans of similar light-load fans. The data suggest the changing internal flow conditions affected by the device conditions.
Detailed Heat Transfer Measurements in a Model of an Integrally Cast Cooling Passage
Authors: Ieronymidis Ioannis , Gillespie David R. H. , Ireland Peter T. , Kingston Robert
Published: January 2010

Detailed measurements of the heat transfer coefficient (htc) distributions on the internal surfaces of a novel gas turbine blade cooling configuration were carried out using a transient liquid crystal technique. The cooling geometry, in which a series of racetrack passages are connected to a central plenum, provides high heat transfer coefficients in regions of the blade in good thermal contact with the outer blade surface. The Reynolds number changes along its length because of the ejection of fluid through a series of 19 transfer holes in a staggered arrangement, which are used to connect ceramic cores during the casting process. Heat transfer coefficient distributions on these holes surface are particularly important in the prediction of blade life, as are heat transfer coefficients within the hole. The results at passage inlet Reynolds numbers of 21,667, 45,596, and 69,959 are presented along with in-hole htc distributions at Rehole=5930, 12,479, 19,147; and suction ratios of 0.98, 1.31, 2.08, and 18.67, respectively. All values are engine representative. Characteristic regions of high heat transfer downstream of the transfer holes were observed with enhancement of up to 92% over the Dittus–Boelter level. Within the transfer holes, the average htc level was strongly affected by the cross-flow at the hole entrance. htc levels were low in these short (l/d=1.5) holes fed from regions of developed boundary layer.
Numerical Investigation on the Self-Induced Unsteadiness in Tip Leakage Flow for a Transonic Fan Rotor
Authors: Du Juan , Lin Feng , Zhang Hongwu , Chen Jingyi
Published: January 2010

A numerical investigation on the self-induced unsteadiness in tip leakage flow is presented for a transonic fan rotor. NASA Rotor 67 is chosen as the computational model. It is found that under certain conditions the self-induced unsteadiness can be originated from the interaction of two important driving “forces:” the incoming main flow and the tip leakage flow. Among all the simulated cases, the self-induced unsteadiness exists when the size of the tip clearance is equal to or larger than the design tip clearance. The originating mechanism of the unsteadiness is clarified through time-dependent internal flow patterns in the rotor tip region. It is demonstrated that when strong enough, the tip leakage flow impinges the pressure side of neighboring blade and alters the blade loading significantly. The blade loading in turn changes the strength of the tip leakage flow and results in a flow oscillation with a typical signature frequency. This periodic process is further illustrated by the time-space relation between the driving forces. A correlation based on the momentum ratio of tip leakage flow over the incoming main flow at the tip region is used as an indicator for the onset of the self-induced unsteadiness in tip leakage flow. It is discussed that the interaction between shock wave and tip leakage vortex does not initiate the self-induced unsteadiness, but might be the cause of other types of unsteadiness, such as broad-banded turbulence unsteadiness.
Heat Transfer in Radially Rotating Pin-Fin Channel at High Rotation Numbers
Authors: Chang Shyy Woei , Liou Tong-Miin , Yang Tsun Lirng , Hong Guo Fang
Published: January 2010

Endwall heat transfer measurements for a radially rotating rectangular pin-fin channel with the width-to-height ratio (aspect ratio) of 8 are performed at the parametric conditions of 5000≤Re≤20,000, 0≤Ro≤1.4, and 0.1≤Δρ/ρ≤0.21. Centerline heat transfer levels along the leading and trailing endwalls of the rotating pin-fin channel are, respectively, raised to 1.77–3.72 and 3.06–5.2 times of the Dittus–Boelter values. No previous attempt has examined the heat transfer performances for the pin-fin channel at such high rotation numbers. A selection of experimental data illustrates the individual and interactive Re, Ro, and buoyancy number (Bu) effects on heat transfer. Spanwise heat transfer variations between two adjoining pin rows are detected with the averaged Nusselt numbers (Nu) determined. A set of empirical equations that calculates Nu values over leading and trailing endwalls in the developed flow region is derived to correlate all the heat transfer data generated by this study and permits the evaluation of interactive and individual effects of Re, Ro, and Bu on Nu. With the aid of the Nu correlations derived, the operating conditions with the worst heat transfer scenarios for this rotating pin-fin channel are identified.
Measurement of adsorption isotherms in the gas phase on native titanium dioxide surfaces by quartz crystal microbalance technique
Authors: Marx A. , Langel W.
Published: January 2010

The surface of air exposed titanium dioxide is known to be significantly covered with hydrocarbons, which modify the properties of titanium based materials such as used for human implants. The n alcohols are among the most important organic contaminants in the ambient atmosphere with typical partial pressures of 5×10−3 Pa [50 ppb (parts per 109)]. The authors measured adsorption isotherms of H2O and n alcohols up to butanol in the pressure range of 10−6–1000 Pa in a UHV chamber with a quartz crystal microbalance. The crystals were covered by physical vapor deposition titanium layers passivated in oxygen atmosphere. Significant adsorption was observed in the pressure range equivalent to atmospheric contamination. The data were fitted by sums of Brunauer, Emmett and Teller (BET) isotherms with a spectrum of adsorption energies ranging from the evaporation enthalpies of about 40 to 100 kJ/mol. Due to the high energy contributions, significant coverage of TiO2 by n alcohols is already possible at their typical partial pressures in air.
Wind in the Solar System
Authors: McIntosh Gordon
Published: January 2010

As an astronomy instructor I am always looking for commonly experienced Earthly phenomena to help my students and me understand and appreciate similar occurrences elsewhere in the solar system. Recently I wrote short TPT articles on frost1 and precipitation.2 The present article is on winds in the solar system. A windy day or storm might motivate the inclusion of this subject into a lecture.
Online Self-Reporting of Pencil-and-Paper Homework
Authors: Trawick Matthew L.
Published: January 2010

Physics teachers are most effective when their students are active learners who think and participate in every class. This extends beyond the classroom too: ideally, students would tackle challenging questions and exercises after every class—not just before the exam or the night before the weekly homework is due.1 Just-in-Time-Teaching2 was developed to encourage this by having students submit daily homework online; their answers can be quickly graded (by hand) and then used as a springboard for class discussions that day. More recently, online homework services have become available that can automate the grading process and provide instantaneous feedback to students. Unfortunately in both of these cases, the range of possible questions is limited to what can be easily answered via computer. But while pencil and paper is still an easier medium for expressing diagrams and equations, daily collection of paper homework is cumbersome and does not allow same-day feedback. This paper describes a hybrid strategy in which students solve what may be “standard” pencil-and-paper homework problems, and then use a simple online form to self-report their degree of success.
Poisson spot with magnetic levitation
Authors: Hoover Matthew , Everhart Michael , D'Arruda Jose
Published: January 2010

In this paper we describe a unique method for obtaining the famous Poisson spot without adding obstacles to the light path, which could interfere with the effect. A Poisson spot is the interference effect from parallel rays of light diffracting around a solid spherical object, creating a bright spot in the center of the shadow.
Getting impulsive
Authors: Riendeau Diane
Published: January 2010

Special thanks to Shannon Mandel, Barrington High School, Barrington, IL, and Toby Dittrich, Portland Community College, Portland, OR. If you have a favorite YouTube video you use in class, please forward the link and a brief description to Diane at driendeau@dist113.org
Rules for Biologically Inspired Adaptive Network Design
Authors: Tero Atsushi , Takagi Seiji , Saigusa Tetsu , Ito Kentaro , Bebber Dan P. , Fricker Mark D. , Yumiki Kenji , Kobayashi Ryo , Nakagaki Toshiyuki
Published: January 2010

Miniature Transport Engineers

In its vegetative phase, the slime moldPhysarum polycephalum“slimes” its way through the world seeking food. As it explores, it links previously found food sources with tubular structures.Teroet al.(p.439) report that if food sources are deposited on a plate in a pattern corresponding in miniature to the positions of the cities that surround Tokyo, the resulting network ofPhysarumtubules that develops is rather similar in structure to the railroad network that connects the Japanese cities. A model was produced that describes the adaptive network development displayed by the slime mold. This biologically inspired model might provide insight into how to implement properties like resistance of transport systems to local failures into similar human-designed systems.
Slip in the 1857 and Earlier Large Earthquakes Along the Carrizo Plain, San Andreas Fault
Authors: Zielke Olaf , Arrowsmith J Ramón , Ludwig Lisa Grant , Akçiz Sinan O.
Published: January 2010

Slip, Tripped, and Faulted

Earthquake risk assessment can be improved if we were able to quantify the recurrence and magnitude of slip events. Until recently though, a lack of sophisticated seismometers has forced us to rely on anecdotal evidence from those who survived major earthquakes or to look for clues in the landscape.

Zielke
et al.

(p.
1119
, published online 21 January; see the Perspective by

Scharer

) analyzed high-resolution images of the San Andreas Fault in southern California. The data showed that major surface ruptures, such as the 1857 Fort Tejon earthquake, resulted from slips of only about 5 meters; much less than previously thought. In a study that lends support to this discovery,

Grant Ludwig
et al.

(p.
1117
, published online 21 January; see the Perspective by

Scharer

) suggest from analysis of the geomorphic features of this region that several smaller earthquakes have occurred during recent centuries rather than infrequent but larger movements. The Perspective by
Scharer
(p.
1089
) discusses how paleoseismological studies like these may be valuable for feeding data into earthquake prediction.
Did They Fail? Could They Choose?
Questioning Collapse
Human Resilience, Ecological Vulnerability, and the Aftermath of Empire

Patricia A. McAnany and Norman Yoffee, Eds.

Cambridge University Press, Cambridge, 2010. 390 pp. $90, £55. ISBN 9780521515726. Paper, $29.99, £17.99. ISBN 9780521733663.
Authors: Lewis Krista
Published: January 2010

The contributors argue that the paths and causes of societal declines are generally complex and that despite pressures of population and environmental degradation, societies demonstrate considerable resilience.
Subversion from the Sidelines
Authors: Agarwal Nisheeth , Bishai William R.
Published: January 2010

A bacterial peptide subverts epithelial cells, resulting in a remodeling that promotes the early progression of tuberculosis.
Amoeba-Inspired Network Design
Authors: Marwan Wolfgang
Published: January 2010

Computational models of biological self-organizing systems may have real-world applications for optimizing dynamic technological networks.
The Tangled Roots of Agriculture
Authors: Balter Michael
Published: January 2010

A once-popular view that climate change led the Near East's ancient Natufians to begin domesticating plants and animals is under increasing attack, but alternative paradigms are still being formed.
Snapshots From the Meeting
Authors: Kerr Richard A.
Published: January 2010

Snapshots from the fall meeting of the American Geophysical Union include training people how to evacuate safely in the event of a tsunami and the finding that nanodiamonds really do litter the sedimentary record at the geologic moment that the mammoths disappeared.
Nasolacrimal Duct Closure Modulates Ocular Mucosal and Systemic CD4+T-Cell Responses Induced following Topical Ocular or Intranasal Immunization
Authors: Chentoufi Aziz Alami , Dasgupta Gargi , Nesburn Anthony B. , Bettahi Ilham , Binder Nicholas R. , Choudhury Zareen S. , Chamberlain Winston D. , Wechsler Steven L. , BenMohamed Lbachir
Published: January 2010

Both topical ocular and topical intranasal immunizations have been reported to stimulate the ocular mucosal immune system (OMIS) and the systemic immune system. Nasolacrimal ducts (NLDs) are the connecting bridges between the OMIS and nasal cavity-associated lymphoid tissue (NALT). These ducts drain topical ocularly administrated solutions into the inferior meatus of the nose to reach the NALT. Inversely, NLDs also drain intranasally administrated solutions to the mucosal surface of the eye and thus the OMIS. This unique anatomical connection between the OMIS and NALT systems provoked us to test whether the OMIS and NALT are immunologically interdependent. In this report, we show that both topical ocular administration and topical intranasal administration of a mixture of immunodominant CD4+T-cell epitope peptides from herpes simplex virus type 1 (HSV-1) glycoprotein D (gD) emulsified with the CpG2007mucosal adjuvant are capable of inducing local (in conjunctiva) as well as systemic (in spleen) HSV-peptide-specific CD4+T-cell responses. Interestingly, surgical closure of NLDs did not significantly alter local ocular mucosal CD4+T-cell responses induced following topical ocular immunization but did significantly enhance systemic CD4+T-cell responses (as measured by both T-cell proliferation and gamma interferon (IFN-γ) production;P< 0.005). In contrast, NLD closure significantly decreased ocular mucosal, but not systemic, CD4+T-cell responses following intranasal administration of the same vaccine solution (P< 0.001). The study suggests that NALT and the OMIS are immunologically interconnected.
Expression of Homing Receptors on IgA1 and IgA2 Plasmablasts in Blood Reflects Differential Distribution of IgA1 and IgA2 in Various Body Fluids
Authors: Pakkanen Sari H. , Kantele Jussi M. , Moldoveanu Zina , Hedges Spencer , Häkkinen Miikka , Mestecky Jiri , Kantele Anu
Published: January 2010

Although secretory IgA is the most abundantly produced Ig isotype, the mechanisms underlying the differential distribution of IgA subclasses in various body fluids remain unclear. To explore these mechanisms, we examined the distribution of IgA subclasses, the influence of the nature and sites of encounters with antigens, and the correlation between IgA subclass distribution and homing potentials of circulating IgA plasmablasts. IgA1 predominated in serum, tears, nasal wash fluid, and saliva; the levels of IgA1 and IgA2 were comparable in vaginal wash fluid; and IgA2 predominated in intestinal lavage fluids. Seventy-one percent of circulating IgA plasmablasts secreted IgA1. The intestinal homing receptor (HR), α4β7, was expressed more frequently on IgA2 than on IgA1 plasmablasts, with no differences in the expression of other HRs. IgA subclass distribution among circulating antigen-specific antibody-secreting cells (ASC) was dependent on the nature of the antigen: following vaccination withSalmonella entericaserovar Typhi, unconjugated pneumococcal polysaccharide, orHaemophilus influenzaepolysaccharide-diphtheria toxoid conjugate, the proportions of specific IgA1 ASC were 74%, 47%, 56%, and 80%, respectively. HR expression depended on the route of administration: expression of HRs was different after oral than after parenteral vaccination, while no difference was seen between HR expression of antigen-specific IgA1 and IgA2 ASC induced via the same route. The key factors determining IgA subclass distribution in a given secretion are the nature of the antigens encountered at a particular site and the site-specific homing instructions given to lymphocytes at that site. These two factors are reflected as differences in the homing profiles of the total populations of circulating IgA1 and IgA2 plasmablasts.
Sequence Polymorphism and PCR-Restriction Fragment Length Polymorphism Analysis of the Flagellin Gene of
Burkholderia pseudomallei
Authors: Tay Sun Tee , Cheah Pui Ching , Puthucheary Savithiri D.
Published: January 2010

Four flagellin allelic types (I to IV) of
Burkholderia pseudomallei
were identified based on their sequence variation and restriction fragment length polymorphism (RFLP) analysis of the amplified flagellin gene. Flagellin allelic type I was the most predominantly (75.0%) found among the 100 clinical isolates of
B. pseudomallei
investigated in this study.
Evaluation of a Chromogenic Agar under Development To Screen for VRE Colonization
Authors: Kallstrom George , Doern Christopher D. , Dunne W. Michael
Published: January 2010

BBL CHROMagar VanRE (CVRE) was compared with bile esculin azide agar plus vancomycin to screen for vancomycin-resistant enterococcus (VRE) colonization. CVRE distinguishes
Enterococcus faecalis
(green colonies) from
Enterococcus faecium
(mauve colonies) on the basis of chromogenic substrate use. CVRE sensitivity and specificity were 98.6% and 99.1%. Positive and negative predictive values were 95.9% and 99.7%.
Evolutionary Genetics of Human Enterovirus 71: Origin, Population Dynamics, Natural Selection, and Seasonal Periodicity of the VP1 Gene
Authors: Tee Kok Keng , Lam Tommy Tsan-Yuk , Chan Yoke Fun , Bible Jon M. , Kamarulzaman Adeeba , Tong C. Y. William , Takebe Yutaka , Pybus Oliver G.
Published: January 2010

Human enterovirus 71 (EV-71) is one of the major etiologic causes of hand, foot, and mouth disease (HFMD) among young children worldwide, with fatal instances of neurological complications becoming increasingly common. Global VP1 capsid sequences (
n
= 628) sampled over 4 decades were collected and subjected to comprehensive evolutionary analysis using a suite of phylogenetic and population genetic methods. We estimated that the common ancestor of human EV-71 likely emerged around 1941 (95% confidence interval [CI], 1929 to 1952), subsequently diverging into three genogroups: B, C, and the now extinct genogroup A. Genealogical analysis revealed that diverse lineages of genogroup B and C (subgenogroups B1 to B5 and C1 to C5) have each circulated cryptically in the human population for up to 5 years before causing large HFMD outbreaks, indicating the quiescent persistence of EV-71 in human populations. Estimated phylogenies showed a complex pattern of spatial structure within well-sampled subgenogroups, suggesting endemicity with occasional lineage migration among locations, such that past HFMD epidemics are unlikely to be linked to continuous transmission of a single strain of virus. In addition, rises in genetic diversity are correlated with the onset of epidemics, driven in part by the emergence of novel EV-71 subgenogroups. Using subgenogroup C1 as a model, we observe temporal strain replacement through time, and we investigate the evidence for positive selection at VP1 immunogenic sites. We discuss the consequences of the evolutionary dynamics of EV-71 for vaccine design and compare its phylodynamic behavior with that of influenza virus.
Internalization of Coxsackievirus A9 Is Mediated by β2-Microglobulin, Dynamin, and Arf6 but Not by Caveolin-1 or Clathrin
Authors: Heikkilä Outi , Susi Petri , Tevaluoto Tuire , Härmä Heidi , Marjomäki Varpu , Hyypiä Timo , Kiljunen Saija
Published: January 2010

Coxsackievirus A9 (CAV9) is a member of the human enterovirus B species within the
Enterovirus
genus of the family
Picornaviridae
. It has been shown to utilize αV integrins, particularly αVβ6, as its receptors. The endocytic pathway by which CAV9 enters human cells after the initial attachment to the cell surface has so far been unknown. Here, we present a systematic study concerning the internalization mechanism of CAV9 to A549 human lung carcinoma cells. The small interfering RNA (siRNA) silencing of integrin β6 subunit inhibited virus proliferation, confirming that αVβ6 mediates the CAV9 infection. However, siRNAs against integrin-linked signaling molecules, such as Src, Fyn, RhoA, phosphatidylinositol 3-kinase, and Akt1, did not reduce CAV9 proliferation, suggesting that the internalization of the virus does not involve integrin-linked signaling events. CAV9 endocytosis was independent of clathrin or caveolin-1 but was restrained by dynasore, an inhibitor of dynamin. The RNA interference silencing of β2-microglobulin efficiently inhibited virus infection and caused CAV9 to accumulate on the cell surface. Furthermore, CAV9 infection was found to depend on Arf6 as both silencing of this molecule by siRNA and the expression of a dominant negative construct resulted in decreased virus infection. In conclusion, the internalization of CAV9 to A549 cells follows an endocytic pathway that is dependent on integrin αVβ6, β2-microglobulin, dynamin, and Arf6 but independent of clathrin and caveolin-1.
Dendritic Cell Migration Limits the Duration of CD8+T-Cell Priming to Peripheral Viral Antigen
Authors: Schell Amanda M. , Granger Erica L. , Koczot Frank , Fischer Matthew A. , Norbury Christopher C.
Published: January 2010

CD8+T cells (TCD8+) play a crucial role in immunity to viruses. Antiviral TCD8+are initially activated by recognition of major histocompatibility complex (MHC) class I-peptide complexes on the surface of professional antigen-presenting cells (pAPC). Migration of pAPC from the site of infection to secondary lymphoid organs is likely required during a natural infection. Migrating pAPC can be directly infected with virus or may internalize antigen derived from virus-infected cells. The use of experimental virus infections to assess the requirement for pAPC migration in initiation of TCD8+responses has proven difficult to interpret because injected virus can readily drain to secondary lymphoid organs without the need for cell-mediated transport. To overcome this ambiguity, we examined the generation of antigen-specific TCD8+after immunization with recombinant adenoviruses that express antigen driven by skin-specific or ubiquitous promoters. We show that the induction of TCD8+in response to tissue-targeted antigen is less efficient than the response to ubiquitously expressed antigen and that the resulting TCD8+fail to clear all target cells pulsed with the antigenic peptide. This failure to prime a fully functional TCD8+response results from a reduced period of priming to peripherally expressed antigen versus ubiquitously expressed antigen and correlated with a brief burst of pAPC migration from the skin, a requirement for induction of the response to peripheral antigen. These results indicate that a reduced duration of pAPC migration after virus infection likely reduces the amplitude of the TCD8+response, allowing persistence of the peripheral virus.
Influence of Disulfide-Stabilized Structure on the Specificity of Helper T-Cell and Antibody Responses to HIV Envelope Glycoprotein gp120
Authors: Mirano-Bascos Denise , Steede N. Kalaya , Robinson James E. , Landry Samuel J.
Published: January 2010

CD4+helper T cells specific for human immunodeficiency virus type 1 (HIV-1) are associated with control of viremia. Nevertheless, vaccines have had limited effectiveness thus far, in part because sequence variability and other structural features of the HIV envelope glycoprotein deflect the immune response. Previous studies indicated that CD4+T-cell epitope dominance is controlled by antigen three-dimensional structure through its influence on antigen processing and presentation. In this work, three disulfide bonds in the outer domain of gp120 were individually deleted in order to destabilize the local three-dimensional structure and enhance the presentation of nearby weakly immunogenic epitopes. However, upon immunization of groups of BALB/c mice, the CD4+T-cell response was broadly reduced for all three variants, and distinct epitope profiles emerged. For one variant, antibody titers were sharply increased, and the antibody exhibited significant CD4-blocking activity.
Structure Function Studies of Vaccinia Virus Host Range Protein K1 Reveal a Novel Functional Surface for Ankyrin Repeat Proteins
Authors: Li Yongchao , Meng Xiangzhi , Xiang Yan , Deng Junpeng
Published: January 2010

Poxvirus host tropism at the cellular level is regulated by virus-encoded host range proteins acting downstream of virus entry. The functioning mechanisms of most host range proteins are unclear, but many contain multiple ankyrin (ANK) repeats, a motif that is known for ligand interaction through a concave surface. We report here the crystal structure of one of the ANK repeat-containing host range proteins, the vaccinia virus K1 protein. The structure, at a resolution of 2.3 Å, showed that K1 consists entirely of ANK repeats, including seven complete ones and two incomplete ones, one each at the N and C terminus. Interestingly, Phe82 and Ser83, which were previously shown to be critical for K1's function, are solvent exposed and located on a convex surface, opposite the consensus ANK interaction surface. The importance of this convex surface was further supported by our additional mutagenesis studies. We found that K1's host range function was negatively affected by substitution of either Asn51 or Cys47 and completely abolished by substitution of both residues. Cys47 and Asn51 are also exposed on the convex surface, spatially adjacent to Phe82 and Ser83. Altogether, our data showed that K1 residues on a continuous convex ANK repeat surface are critical for the host range function, suggesting that K1 functions through ligand interaction and does so with a novel ANK interaction surface.