bluuebunny/crossref_metadata_2025 huggingface dataset:
Aquifer Vulnerability Assessment Based on Sequence Stratigraphic and 39Ar Transport Modeling
Authors: Sonnenborg Torben O. , Scharling Peter B. , Hinsby Klaus , Rasmussen Erik S. , Engesgaard Peter
Published: May 2015

A large‐scale groundwater flow and transport model is developed for a deep‐seated (100 to 300 m below ground surface) sedimentary aquifer system. The model is based on a three‐dimensional (3D) hydrostratigraphic model, building on a sequence stratigraphic approach. The flow model is calibrated against observations of hydraulic head and stream discharge while the credibility of the transport model is evaluated against measurements of 39Ar from deep wells using alternative parameterizations of dispersivity and effective porosity. The directly simulated 3D mean age distributions and vertical fluxes are used to visualize the two‐dimensional (2D)/3D age and flux distribution along transects and at the top plane of individual aquifers. The simulation results are used to assess the vulnerability of the aquifer system that generally has been assumed to be protected by thick overlaying clayey units and therefore proposed as future reservoirs for drinking water supply. The results indicate that on a regional scale these deep‐seated aquifers are not as protected from modern surface water contamination as expected because significant leakage to the deeper aquifers occurs. The complex distribution of local and intermediate groundwater flow systems controlled by the distribution of the river network as well as the topographical variation (Tóth 1963) provides the possibility for modern water to be found in even the deepest aquifers.
Graphitization of carbonaceous material in sedimentary rocks on short geologic time‐scales: An example from the Kinsho‐zan area, central Japan
Authors: Mori Natsumi , Wallis Simon , Mori Hiroshi
Published: May 2015

Initially amorphous carbonaceous material becomes more crystalline with heating. The structural change depends not only on the maximum attained temperature but also the time‐scale of heating. Raman spectroscopy of natural samples that have been heated for time‐scales of 105 years or greater show that the degree of crystallinity has reached steady‐state. In contrast, laboratory studies show very little change in crystallinity of carbonaceous material (CM) after heating at 1000°C for a time of 3.5 weeks. Better constraints on the time‐scale for crystallization require experiments on time‐scales of years to thousands of years; such long time‐scales can only be derived from natural examples of CM‐bearing rocks that have been heated for a known length of time. Thermal modeling of contact metamorphism developed around a 13 m dike within the Akasaka Limestone in Gifu Prefecture shows the time‐scale of heating is of the order of 1–100 years. Raman spectroscopy reveals a significant increase in the crystallinity of the CM in a region within 3 m from the dike. A comparison between the temperature predicted for the contact aureole and the degree of crystallinity of the carbonaceous material shows that even close to the dike the CM has not reached steady‐state. This change began at over 550°C (modeled temperature) for a time‐scale of heating of a few years. Attaining steady‐state in the crystallization of CM under natural geological condition requires heating on time‐scales greater than about one hundred years. This study shows the utility of using natural laboratory studies to determine the kinetics of CM crystallization in rocks.
Business models and opportunity creation: How IT entrepreneurs create and develop business models under uncertainty
Authors: Ojala Arto
Published: May 2015

How can entrepreneurs develop business models for markets in which the technology is constantly changing—or create business models for markets that do not exist? These are fundamental questions for information technology (IT) entrepreneurs, and for information systems (IS) scholars who seek to develop a theoretical understanding of business models. The case study presented in this paper addressed these questions, demonstrating how a small software firm developed its business model over a 15‐year period in cloud gaming markets. Based on the empirical findings, a preliminary theoretical model is presented. The aim of the model is to increase scholarly understanding of how business models are created and developed in markets in which the future directions of a technology are uncertain. It demonstrates the ways in which a business model may evolve through reassessment and development phases, which can be seen as transition elements linking old and new business models.
‘Porosome’ discovered nearly 20 years ago provides molecular insights into the kiss‐and‐run mechanism of cell secretion
Authors: Jena Bhanu P.
Published: May 2015

Secretion is a fundamental cellular process in living organisms, from yeast to cells in humans. Since the 1950s, it was believed that secretory vesicles completely merged with the cell plasma membrane during secretion. While this may occur, the observation of partially empty vesicles in cells following secretion suggests the presence of an additional mechanism that allows partial discharge of intra‐vesicular contents during secretion. This proposed mechanism requires the involvement of a plasma membrane structure called ‘porosome’, which serves to prevent the collapse of secretory vesicles, and to transiently fuse with the plasma membrane (Kiss‐and‐run), expel a portion of its contents and disengage. Porosomes are cup‐shaped supramolecular lipoprotein structures at the cell plasma membrane ranging in size from 15 nm in neurons and astrocytes to 100–180 nm in endocrine and exocrine cells. Neuronal porosomes are composed of nearly 40 proteins. In comparison, the 120 nm nuclear pore complex is composed of >500 protein molecules. Elucidation of the porosome structure, its chemical composition and functional reconstitution into artificial lipid membrane, and the molecular assembly of membrane‐associated t‐SNARE and v‐SNARE proteins in a ring or rosette complex resulting in the establishment of membrane continuity to form a fusion pore at the porosome base, has been demonstrated. Additionally, the molecular mechanism of secretory vesicle swelling, and its requirement for intra‐vesicular content release during cell secretion has also been elucidated. Collectively, these observations provide a molecular understanding of cell secretion, resulting in a paradigm shift in our understanding of the secretory process.
Relationship of social support and decisional conflict to advance directives attitude in Korean older adults: A community‐based cross‐sectional study
Authors: Lee JuHee , Jung Dukyoo , Choi MoonKi
Published: May 2015

Aim

The aim of this study was to clarify the relationship between social support, decisional conflict, and attitude towards advance directives, and determine whether decisional conflict mediates the relation between social support and advance directives attitude among older adults in South Korea.

Methods

In total, 209 community‐based older adults (mean age, 74.82 years) participated in this cross‐sectional study. Demographic characteristics, self‐perceived health status, social support, decisional conflict, and advance directives attitude were investigated via a structured questionnaire. Data analysis was carried out using Pearson's correlation and path analyses.

Results

The mean score of advance directives attitude was 48.01 (range, 35–61). Decisional conflict and social support were both significantly related to advance directives attitude (P < 0.001). Additionally, decisional conflict was a mediator between social support and advance directives attitudes.

Conclusion

The results confirmed the importance of social support for reducing decisional conflict and encouraging positive attitudes toward advance directives. Future studies are needed to support the development of culturally sensitive educational approaches regarding advance directives for older adults in Korea.
Keynesian Inefficiency and Optimal Policy: A New Monetarist Approach
Authors: WILLIAMSON STEPHEN D.
Published: May 2015

A simple model of monetary/labor search is constructed to study Keynesian indeterminacy and optimal policy. In the model, economic agents have trouble splitting the surplus from exchange appropriately, and we consider monetary and fiscal policies that correct this Keynesian inefficiency. A Taylor rule neither implies determinacy, nor does it support an efficient outcome. An optimal policy yields an efficient and determinate allocation of resources, but equilibrium policy actions, wages, and prices are indeterminate at the optimum.
Using Survey Data of Inflation Expectations in the Estimation of Learning and Rational Expectations Models
Authors: ORMEÑO ARTURO , MOLNÁR KRISZTINA
Published: May 2015

Does survey data contain useful information for estimating macroeconomic models? We address this question by using survey data of inflation expectations to estimate the New Keynesian model by Smets and Wouters () and compare its performance under rational expectations and adaptive learning. The survey information serves as an additional moment restriction and helps us to determine the learning agents' forecasting model for inflation. Adaptive learning fares similarly to rational expectations in fitting macro data, but clearly outperforms rational expectations in fitting macro and survey data simultaneously. In other words, survey data contain additional information that is not present in the macro data alone.
Do Central Bank Forecasts Influence Private Agents? Forecasting Performance versus Signals
Authors: HUBERT PAUL
Published: May 2015

Focusing on a set of central banks that publish inflation forecasts in real time, this paper aims to establish whether central bank inflation forecasts influence private inflation forecasts. The response is positive in the five countries studied: Sweden, the United Kingdom, Canada, Switzerland, and Japan. Three hypotheses may explain this central bank influence: central bank forecasts are more accurate than private ones, are based on different information sets, and/or convey signals about future policy decisions and policymakers’ preferences and objectives. We provide evidence that the source of these central banks’ influence is not linked to their forecasting performance.
Anterior migration of lateral plate mesodermal cells during embryogenesis of the pufferfish Takifugu niphobles: insight into the rostral positioning of pelvic fins
Authors: Tanaka Mikiko , Yu Reiko , Kurokawa Daisuke
Published: May 2015

In vertebrates, paired appendages (limbs and fins) are derived from the somatic mesoderm subsequent to the separation of the lateral plate mesoderm into somatic and splanchnic layers. This is less clear for teleosts, however, because the developmental processes of separation into two layers and of extension over the yolk have rarely been studied. During teleost evolution, the position of pelvic fins has generally shifted rostrally (Rosen; Nelson, 1982, 1994), although at the early embryonic stage the presumptive pelvic fin cells are initially located near the future anus region – the anterior border of hoxc10a expression in the spinal cord – regardless of their final destination. Our previous studies in zebrafish (abdominal pelvic fins) and Nile tilapia (thoracic pelvic fins) showed that the presumptive pelvic fin cells shift their position with respect to the body trunk after its protrusion from the yolk surface. Furthermore, in Nile tilapia, presumptive pelvic fin cells migrate anteriorly on the yolk surface. Here, we examined the embryonic development of the lateral plate mesoderm at histological levels in the pufferfish Takifugu niphobles, which belongs to the highly derived teleost order Tetraodontiformes, and lacks pelvic fins. Our results show that, in T. niphobles, the lateral plate mesoderm bulges out as two separate layers of cells alongside the body trunk prior to its further extension to cover the yolk sphere. Once the lateral plate mesoderm extends laterally, it rapidly covers the surface of the yolk. Furthermore, cells located near the anterior border of hoxc10a expression in the spinal cord reach the anterior‐most region of the yolk surface. In light of our previous and current studies, we propose that anterior migration of presumptive pelvic fin cells might be required for them to reach the thoracic or more anterior positions as is seen in other highly derived teleost groups.
Genetically induced abnormal cranial development in human trisomy 18 with holoprosencephaly: comparisons with the normal tempo of osteogenic–neural development
Authors: Reid Shaina N. , Ziermann Janine M. , Gondré‐Lewis Marjorie C.
Published: May 2015

Craniofacial malformations are common congenital defects caused by failed midline inductive signals. These midline defects are associated with exposure of the fetus to exogenous teratogens and with inborn genetic errors such as those found in Down, Patau, Edwards' and Smith–Lemli–Opitz syndromes. Yet, there are no studies that analyze contributions of synchronous neurocranial and neural development in these disorders. Here we present the first in‐depth analysis of malformations of the basicranium of a holoprosencephalic (HPE) trisomy 18 (T18; Edwards' syndrome) fetus with synophthalmic cyclopia and alobar HPE. With a combination of traditional gross dissection and state‐of‐the‐art computed tomography, we demonstrate the deleterious effects of T18 caused by a translocation at 18p11.31. Bony features included a single developmentally unseparated frontal bone, and complete dual absence of the anterior cranial fossa and ethmoid bone. From a superior view with the calvarium plates removed, there was direct visual access to the orbital foramen and hard palate. Both the eyes and the pituitary gland, normally protected by bony structures, were exposed in the cranial cavity and in direct contact with the brain. The middle cranial fossa was shifted anteriorly, and foramina were either missing or displaced to an abnormal location due to the absence or misplacement of its respective cranial nerve (CN). When CN development was conserved in its induction and placement, the respective foramen developed in its normal location albeit with abnormal gross anatomical features, as seen in the facial nerve (CNVII) and the internal acoustic meatus. More anteriorly localized CNs and their foramina were absent or heavily disrupted compared with posterior ones. The severe malformations exhibited in the cranial fossae, orbital region, pituitary gland and sella turcica highlight the crucial involvement of transcription factors such as TGIF, which is located on chromosome 18 and contributes to neural patterning, in the proper development of neural and cranial structures. Our study of a T18 specimen emphasizes the intricate interplay between bone and brain development in midline craniofacial abnormalities in general.
Health value & perceived control over health: behavioural constructs to support Type 2 diabetes self‐management in clinical practice
Authors: Nugent Linda Elizabeth , Carson Maggie , Zammitt Nicola Naomi , Smith Graeme Drummond , Wallston Kenneth A
Published: May 2015

Aims and objectives

To explore health value and perceived control over health in relation to self‐management behaviours in adults with Type 2 diabetes mellitus.

Background

Helping people to modify health related behaviour in diabetes is complex due to a multitude of factors. Exploring the meaning of the constructs of Modified Social Learning Theory could be beneficial to identifying people at risk of poor diabetes self‐management.

Design

An exploratory qualitative study.

Methods

Thirteen adults with insulin‐treated Type 2 diabetes mellitus were purposively sampled. Data were collected through semi‐structured interviews. An in‐depth thematic analysis was carried out.

Results

Health became a value priority on diagnosis of Type 2 diabetes mellitus. Participants described holding both terminal (relating to desired end states) and instrumental (a means to an end) health values pre‐diagnosis but these became instrumental post‐diagnosis to meet new lifestyle needs and maintain their quality of life. Descriptions of ‘conflicts’ in locus of control beliefs when managing Type 2 diabetes mellitus demonstrated influences on levels of self‐efficacy and health value. Common themes that impacted on diabetes self‐management included co‐morbidities, medication management, blood glucose monitoring and reasoning for Type 2 diabetes mellitus.

Conclusions

Locus of control beliefs, levels of self‐efficacy and health value were influenced by complications associated with Type 2 diabetes mellitus. The findings on Modified Social Learning Theory and instrumental health value as a moderator to health behaviour resulted in the development of a proposed framework with potential practical utility.

Relevance to clinical practice

This research demonstrates the relevance of exploring the constructs of Modified Social Learning Theory (MSLT) in relation to diabetes self‐management behaviours in Type 2 diabetes mellitus. The proposed Type 2 diabetes mellitus Self‐management Behaviour Support framework incorporates Modified Social Learning Theory and instrumental health value as the theoretical basis for development and could provide clinical nurses and doctors with a tool that will allow for in‐depth assessment and planning of Type 2 diabetes mellitus patients' self‐management behaviours.
NLRP3 gene polymorphisms in Iranian patients with recurrent aphthous stomatitis
Authors: Bidoki Alireza Zare , Harsini Sara , Sadr Maryam , Soltani Samaneh , Mohammadzadeh Mahsa , Najafi Shamsolmoulouk , Rezaei Nima
Published: May 2015

Background

Recurrent aphthous stomatitis (RAS) is a common disorder with an unclear etiopathogenesis. Involvement of the immune system in the development of this condition is strongly suggested. As the variations in the inflammasome‐related NLRP3 gene have been suggested to affect immune system activity, this case–control study was performed to determine whether these genetic variants are associated with RAS.

Methods

We studied a group of 69 Iranian patients with RAS in comparison with 56 healthy controls. We determined four single nucleotide polymorphisms (SNPs) of NLRP3 and performed association analyses of NLRP3. Genotyping was conducted using the TaqMan method.

Results

The NLRP3 rs3806265 T allele was significantly more frequent in the patients with RAS than in the healthy controls (P = 0.003). While a significant negative association was found between the C allele at the same position with RAS (P = 0.003), the TT genotype was significantly more frequent at position rs3806265 in NLRP3 in patient group than in the controls (P = 0.002). However, the frequency of CT genotype at the same position was significantly higher in healthy controls than in the case category (P = 0.002).

Conclusions

Considering the high frequency of the presence of NLRP3 rs3806265 TT genotype in patients with RAS, it seems that this gene polymorphism could affect individual susceptibility to RAS.
Occurrence of Passalora Leaf Spot Caused by Passalora ampelopsidis on Virginia Creeper in Korea
Authors: Park Ji‐Hyun , Park Mi‐Jeong , Han Kyung‐Sook , Cho Sung‐Eun , Shin Hyeon‐Dong
Published: May 2015

A previously unknown leaf spot disease was observed on Virginia creeper (Parthenocissus quinquefolia) vines in Seoul, Korea. Affected plants exhibited leaf spots and discoloration, resulting in leaf blight and premature defoliation. The causal agent of the disease was identified as Passalora ampelopsidis by comparing morphological characteristics and analyzing the internal transcribed spacer region of the rDNA. Pathogenicity tests were conducted twice with the same results, fulfilling Koch's postulates. Passalora leaf spot on Virginia creeper vines was first recorded in the United States in 1878. Recent reports of Passalora leaf spots on Virginia creeper vines in 2005 in Germany, in 2012 in China and now in Korea indicate the prevalence of the disease.
Connecting genotypes, phenotypes and fitness: harnessing the power of CRISPR/Cas9 genome editing
Authors: Bono Jeremy M. , Olesnicky Eugenia C. , Matzkin Luciano M.
Published: May 2015

One of the fundamental goals in evolution and ecology is to identify the genetic basis of adaptive phenotypes. Unfortunately, progress towards this goal has been hampered by a lack of genetic tools available for nonmodel organisms. The exciting new development of the CRISPR (clustered regularly interspaced short palindromic repeat)/Cas9 (CRISPR‐associated nuclease 9) genome‐editing system now promises to transform the field of molecular ecology by providing a versatile toolkit for manipulating the genome of a wide variety of organisms. Here, we review the numerous applications of this groundbreaking technology and provide a practical guide to the creation of genetic knockouts, transgenics and other related forms of gene manipulation in nonmodel organisms. We also specifically discuss the potential uses of the CRISPR/Cas9 system in ecological and evolutionary studies, which will further advance the field towards the long‐standing goal of connecting genotypes, phenotypes and fitness.
A Nicotiana attenuata cell wall invertase inhibitor (NaCWII) reduces growth and increases secondary metabolite biosynthesis in herbivore‐attacked plants
Authors: Ferrieri Abigail P. , Arce Carla C. M. , Machado Ricardo A. R. , Meza‐Canales Ivan D. , Lima Eraldo , Baldwin Ian T. , Erb Matthias
Published: May 2015

Plant invertases are sucrolytic enzymes that are essential for the regulation of carbohydrate metabolism and source–sink relationships. While their activity has been well documented during abiotic and biotic stresses, the role of proteinaceous invertase inhibitors in regulating these changes is unknown.

Here, we identify a putative Nicotiana attenuata cell wall invertase inhibitor (NaCWII) which is strongly up‐regulated in a jasmonate (JA)‐dependent manner following simulated attack by the specialist herbivore Manduca sexta. To understand the role of NaCWII in planta, we silenced its expression by RNA interference and measured changes in primary and secondary metabolism and plant growth following simulated herbivory.

NaCWII‐silenced plants displayed a stronger depletion of carbohydrates and a reduced capacity to increase secondary metabolite pools relative to their empty vector control counterparts. This coincided with the attenuation of herbivore‐induced CWI inhibition and growth suppression characteristic of wild‐type plants.

Together our findings suggest that NaCWII may act as a regulatory switch located downstream of JA accumulation which fine‐tunes the plant's balance between growth and defense metabolism under herbivore attack. Although carbohydrates are not typically viewed as key factors in plant growth and defense, our study shows that interfering with their catabolism strongly influences plant responses to herbivory.
Photophysics and Rotational Dynamics of a Hydrophilic Molecule in a Room Temperature Ionic Liquid
Authors: Chatterjee Aninda , Maity Banibrata , Ahmed Sayeed Ashique , Seth Debabrata
Published: May 2015

We have studied the photophysics and rotational diffusion of hydrophilic solute 7‐(N, N′‐diethylamino)coumarin‐3‐carboxylic acid (7‐DCCA) in a room temperature ionic liquid methyltrioctylammonium bis(trifluoromethylsulfonyl) imide ([N1888][NTf2]). Comparison of activation energies of viscous flow and nonradiative decay shows that the photophysical properties of 7‐DCCA are not guided by the bulk viscosity of the medium but are dependent on the specific solute solvent interaction and structural heterogeneity of the medium. The rotational relaxation behaviour of 7‐DCCA in [N1888][NTf2] shows significant deviation from the Stokes Einstein Debye hydrodynamic model of rotational diffusion. This is indicative of the influence of specific solute solvent interaction on the rotational relaxation behaviour of 7‐DCCA. Comparison of activation energy of rotational relaxation with activation energy of viscous flow clearly reinforces our assumption that the structural heterogeneity of the medium and specific solute solvent interaction plays a dominant role on the rotational diffusion instead of bulk viscosity.
The Trade Consequences of Maritime Insecurity: Evidence from Somali Piracy
Authors: Burlando Alfredo , Cristea Anca D. , Lee Logan M.
Published: May 2015

In the past decade (2000–2010), pirates from Somalia have carried out thousands of attacks on cargo ships sailing through the Gulf of Aden and the Indian Ocean, causing what others have identified as significant damage to maritime trade. In this paper, we use variations in the spread and intensity of Somali piracy to estimate its effect on the volume of international trade. By comparing trade volume changes along shipping routes located in pirate waters to those that are not, we estimate that Somali piracy reduced bulk commodities trade passing through the Gulf of Aden by 4.1% per year from 2000 to 2010. We find smaller reductions in total trade, consistent with the fact that not all goods are shipped by sea or are targets of pirate attacks. While our estimates suggest that the trade costs of piracy are much lower than what has been suggested in the existing literature, we find that they remain significant and unevenly distributed, with five countries and the EU shouldering 70% of the total costs.
Teaching telehealth consultation skills
Authors: Rienits Helen , Teuss Greg , Bonney Andrew
Published: May 2015

Background

Although teleconsultations have been used for many years in Australia, there has been a recent increase following new government incentives. There is a paucity of literature on enabling medical students to acquire the relevant skills. With a focus on equipping students for practice in rural and remote areas, our medical school has developed an innovative clinical skills lesson to prepare our students for their rural practice placements.

Methods

This lesson was delivered to all students in their third year of training in small groups to enable interactive learning. The objectives of the lesson were to familiarise students with: the various methods of conducting teleconsultations currently in use; the legal and ethical considerations; the technical and procedural issues; and the barriers and benefits for patients and doctors. Students rotated through four different stations over 2 hours and the lesson was evaluated using a student survey.

Results

Medical students self‐reported statistically significant improvements in understanding the issues and procedures, and in confidence in conducting a telehealth consultation.

Discussion

Analysis of the results and student comments demonstrated that students recognise the value of telemedicine learning, and benefit from formal teaching on all aspects of telemedicine, including technology, ethics and protocols. Interestingly, the students found the opportunity to discuss areas such as the ethics of, and barriers to, the use of teleconsultations to be the most challenging and helpful of all of the stations.

There is a paucity of literature on enabling medical students to acquire the relevant [teleconsultation] skills
Competitive ability of ALS‐inhibitor herbicide‐resistant Fimbristylis miliacea
Authors: Schaedler C E , Burgos N R , Noldin J A , Alcober E A , Salas R A , Agostinetto D
Published: May 2015

Fimbristylis miliacea, a weed in rice, has evolved resistance to acetolactate synthase (ALS) inhibitors. This study aimed to investigate the competitive abilities of ALS‐resistant (R) and ALS‐susceptible (S) F. miliacea with rice. A replacement series experiment was conducted in the glasshouse at the Federal University of Pelotas, Brazil. The proportions of rice to F. miliacea were 100:0, 75:25, 50:50, 25:75 and 0:100, with 1060 plants m−2. The experimental units were arranged in a completely randomised design with four replications. A follow‐up study was conducted at the University of Arkansas, Fayetteville, USA, in a split‐plot design with four replications. The main plot was species mixture (rice × R, rice × S, R × S). The subplot was competition partitioning (below‐ and above‐ground, below‐ground only, above‐ground only and no interspecific competition). Leaf area, plant height and shoot dry mass were recorded. Rice was more competitive than the R or S F. miliacea. In equal proportions of rice and F. miliacea, regardless of ecotype, the relative leaf area, height and dry mass of rice were greater than that of F. miliacea. The ALS‐resistant ecotype was less competitive with rice than the S ecotype. Intraspecific competition among rice plants was stronger than rice competition with F. miliacea. Competition for below‐ground resources was the most critical aspect of interference among rice and F. miliacea. In production fields, high infestation levels of F. miliacea results in significant yield losses; thus, resistance to ALS inhibitors needs to be curtailed.
Indirect activation elicits strong correlations between light and electrical responses in ON but not OFF retinal ganglion cells
Authors: Im Maesoon , Fried Shelley I.
Published: May 2015

Key points

To improve the quality of vision elicited by retinal prosthetics, elicited neural activity should resemble physiological signalling patterns; here, we hypothesized that electric stimulation that activates the synaptic circuitry of the retina would lead to closer matches than that which activates ganglion cells directly.

We evaluated this hypothesis by comparing light and electrical responses in different types of ganglion cells.

In contrast to the similarity in their light responses, electrical responses in ON and OFF cells of the same type were quite distinct. Further, electrical and light responses in the same cell were much better correlated in ON vs. OFF ganglion cells. Stimuli that activated photoreceptors yielded better correlations than those which activated bipolar cells.

Our results suggest that the closer match to physiology in the ON signal transmitted to the brain may help to explain preferential reports of ‘bright’ phosphenes during earlier clinical trials.

To improve the efficacy of microelectronic retinal prosthetics it will be necessary to better understand the response of retinal neurons to electric stimulation. While stimulation that directly activates ganglion cells generally has the lowest threshold, the similarity in responsiveness across cells makes it extremely difficult for such an approach to re‐create cell‐type specific patterns of neural activity that arise normally in the healthy retina. In contrast, stimulation that activates neurons presynaptic to ganglion cells utilizes at least some of the existing retinal circuitry and therefore is thought to produce neural activity that better matches physiological signalling. Surprisingly, the actual benefit(s) of this approach remain unsubstantiated. Here, we recorded from ganglion cells in the rabbit retinal explant in response to electrical stimuli that activated the network. Targeted cells were first classified into known types via light responses so that the consistency of electrical responses within individual types could be evaluated. Both transient and sustained ON ganglion cells exhibited highly consistent electrical response patterns which were distinct from one another. Further, properties of the response (interspike interval, latency, peak firing rate, and spike count) in a given cell were well correlated to the corresponding properties of the light response for that same cell. Electric responses in OFF ganglion cells formed two groups, distinct from ON groups, and the correlation levels between electric and light responses were much weaker. The closer match in ON pathway responses may help to explain some preferential reporting of bright stimuli during psychophysical testing.
Simulation of Secondary Contact to Generate Very High Accelerations
Authors: Douglas Stuart T. , Al-Bassyiouni Moustafa , Dasgupta Abhijit , Gilman Kevin , Brown Aaron
Published: May 2015

This paper investigates the design of a typical commercially available drop system for generating very high shock and drop accelerations. Some commercially available drop towers produce accelerations greater than 5000 G by utilizing the dynamics of secondary impact, using an attachment termed a dual mass shock amplifier (DMSA). Depending on the design, some DMSAs are capable of repeatedly generating accelerations as high as 100,000 G. The results show that a finite element model (FEM) can capture the peak acceleration for the drop tower and the DMSA within 15%. In this paper, a detailed description of the test equipment and modeling techniques is provided. The effects of different design parameters, such as table mass, spring stiffness, and programmer material properties, on the drop profile, are investigated through parametric modeling. The effects of contact parameters on model accuracy are explored, including constraint enforcement algorithms, contact stiffness, and contact damping. Simple closed-form analytic models are developed, based on the basic principles of a single impact and the dynamics of secondary impact. Model predictions are compared with test results. Details of the test methodology and simulations guidelines are provided. Detailed finite element analysis (FEA) is conducted and validated against the experimental tests and compared to the simplified theoretical simulations. Benefits in exploring FEM to simulate contact between materials can be extrapolated to different architectures and materials such that with minimal experimental validation impact acceleration can be determined.
Load Carrying Capacities of Butt Welded Joints in High Strength Steels
Authors: Khurshid M. , Barsoum Z. , Barsoum I.
Published: May 2015

The aim of this study is to investigate the influence of yield strength of the filler material and weld metal penetration on the load carrying capacity of butt welded joints in high-strength steels (HSS) (i.e., grade S700 and S960). These joints are manufactured with three different filler materials (under-matching, matching, and over-matching) and full and partial weld metal penetrations. The load carrying capacities of these mentioned joints are evaluated with experiments and compared with the estimations by finite element analysis (FEA), and design rules in Eurocode3 and American Welding Society Code AWS D1.1. The results show that load carrying estimations by FEA, Eurocode3, and AWS D1.1 are in good agreement with the experiments. It is observed that the global load carrying capacity and ductility of the joints are affected by weld metal penetration and yield strengths of the base and filler materials. This influence is more pronounced in joints in S960 steel welded with under-matched filler material. Furthermore, the base plate material strength can be utilized in under-matched butt welded joints provided appropriate weld metal penetration and width is assured. Moreover, it is also found that the design rules in Eurocode3 (valid for design of welded joints in steels of grade up to S700) can be extended to designing of welds in S960 steels by the use of correlation factor of one.
Cyclic Constitutive Response and Effective S–N Diagram of M50 NiL Case-Hardened Bearing Steel Subjected to Rolling Contact Fatigue
Authors: Bhattacharyya Abir , Pandkar Anup , Subhash Ghatu , Arakere Nagaraj
Published: May 2015

A combined experimental and numerical method is developed to estimate the continuously evolving cyclic plastic strain amplitudes in plastically deformed subsurface regions of a case-hardened M50 NiL steel rod subjected to rolling contact fatigue (RCF) over several hundred million cycles. The subsurface hardness values measured over the entire plastically deformed regions and the elastoplastic von Mises stresses determined from the three-dimensional (3D) Hertzian contact finite element (FE) model have been used in conjunction with Neuber's rule to estimate the evolved cyclic plastic strain amplitudes at various points within the RCF-affected zone. The cyclic stress–strain plots developed as a function of case depth revealed that cyclic hardening exponent of the material is greater than the monotonic strain-hardening exponent. Effective S–N diagram for the RCF loading of the case-hardened steel has been presented and the effect of compressive mean stress on its fatigue strength has been explained using Haigh diagram. The compressive mean stress correction according to Haigh diagram predicts that the allowable fatigue strength of the steel increases by a factor of two compared to its fatigue limit before mean stress correction, thus potentially allowing the rolling element bearings to operate over several hundred billion cycles. The methodology presented here is generalized and can be adopted to obtain the constitutive response and S–N diagrams of both through- and case-hardened steels subjected to RCF.
Why We Retweet: Factors Influencing Intentions to Share Sport News on Twitter
Authors: Boehmer Jan , Tandoc Edson C.
Published: May 2015

The current study explored factors influencing content sharing on Twitter in the context of sport news. It employed a 2-step text-based analysis combining qualitative and quantitative approaches and found that 3 main categories of factors are influencing retweeting decisions: characteristics of the source, characteristics of the message, and characteristics of the user. A subsequent hierarchical-regression analysis revealed that factors related to a user’s encounter of a Tweet are the best predictor of retweeting intentions. More specifically, interest in the exact topic of the tweet, the perceived relevance that the tweet might have for the user’s own followers, and similarity in opinion play important roles. Implications for communication practitioners, as well as research investigating human behavior on social media, are discussed.
Advances in addiction research: Applying genetic biomarkers to personalize treatments
Authors: Brooks Andrew , Baurley James
Published: May 2015

Advancements in genetics, sequencing technology, and bioinformatics are changing the principles of current medical practice and transforming the standards of patient care. Genetic detection of common and rare variants within populations provides valuable information about predisposition and vulnerability to complex human disease. Data from large-scale genome-wide association studies have identified genetic variations correlated to biological events, enabling combinations of genetic and non-genetic markers to be translated into potential diagnostic tools. However, aspects of these programs are still evolving, including best practices for protocol development, sample processing, genetic/genomic analysis, data management, and quality control. In this webinar, our expert panel will discuss how to better define these procedures and maximize the use of precious, limited clinical samples by utilizing recent innovations, advances in technology, and current best practices.

View the Webinar
Reading the tea leaves for effects of climate change
Authors: Larson Christina
Published: May 2015

Cloudy forecast for crops cherished for their complex flavors.
Debate sharpens over proposed criteria for NSF grants
Authors: Mervis Jeffrey
Published: May 2015

Supporters say new laws would bolster national priorities; critics see political interference.
A close view of photosystem I
Authors: Croce Roberta
Published: May 2015

A high-resolution structure provides insight into solar energy conversion during photosynthesis

[Also see Research Article by

Qin
et al.

]
Fast and furious: Why all CARs are not made equal
Authors: Dronca Roxana
Published: May 2015

4-1BB can mitigate CAR endodomain-induced T cell exhaustion and prolong T cell survival.
Herpes Simplex Virus 1 Suppresses the Function of Lung Dendritic Cells via Caveolin-1
Authors: Wu Bing , Geng Shuang , Bi Yanmin , Liu Hu , Hu Yanxin , Li Xinqiang , Zhang Yizhi , Zhou Xiaoyu , Zheng Guoxing , He Bin , Wang Bin
Published: May 2015

Caveolin-1 (Cav-1), the principal structural protein of caveolae, has been implicated as a regulator of virus-host interactions. Several viruses exploit caveolae to facilitate viral infections. However, the roles of Cav-1 in herpes simplex virus 1 (HSV-1) infection have not fully been elucidated. Here, we report that Cav-1 downregulates the expression of inducible nitric oxide synthase (iNOS) and the production of nitric oxide (NO) in dendritic cells (DCs) during HSV-1 infection. As a result, Cav-1 deficiency led to an accelerated elimination of virus and less lung pathological change following HSV-1 infection. This protection was dependent on iNOS and NO production in DCs. Adoptive transfer of DCs with Cav-1 knockdown was sufficient to confer the protection to wild-type (WT) mice. In addition, Cav-1 knockout (KO) (Cav-1−/−) mice treated with an iNOS inhibitor exhibited significantly reduced survival compared to that of the nontreated controls. We found that Cav-1 colocalized with iNOS and HSV-1 in caveolae in HSV-1-infected DCs, suggesting their interaction. Taken together, our results identified Cav-1 as a novel regulator utilized by HSV-1 to evade the host antiviral response mediated by NO production. Therefore, Cav-1 might be a valuable target for therapeutic approaches against herpesvirus infections.
Pediatric Staphylococcus aureus Isolate Genotypes and Infections from the Dawn of the Community-Associated Methicillin-Resistant S. aureus Epidemic Era in Chicago, 1994 to 1997
Authors: David Michael Z. , Acree Mary Ellen , Sieth Julia J. , Boxrud Dave J. , Dobbins Ginette , Lynfield Ruth , Boyle-Vavra Susan , Daum Robert S.
Published: May 2015

Widespread infections with community-associated (CA) methicillin-resistant
Staphylococcus aureus
(MRSA) have occurred in the United States with the dissemination of the USA300 strain beginning in 2000. We examined 105 isolates obtained from children treated at the University of Chicago from 1994 to 1997 (75 methicillin-susceptible
S. aureus
[MSSA] and 30 MRSA isolates) in order to investigate for possible evidence of USA300 during this period. Infections were defined epidemiologically based on medical record review. The isolates underwent multilocus sequence typing (MLST), as well as assays for the Panton-Valentine leukocidin (PVL) genes, the protein A gene (
spa
), and
arcA
and
opp3
, proxy markers for the arginine catabolic mobile element (ACME), characteristic of USA300 MRSA. MRSA isolates also underwent staphylococcal cassette chromosome
mec
(SCC
mec
) typing and pulsed-field gel electrophoresis (PFGE) subtyping. MSSA isolates belonged to 17 sequence type (ST) groups. The 12 epidemiologically defined CA-MRSA infection isolates were either ST1 (
n
= 4) or ST8 (
n
= 8). They belonged to 3 different PFGE types: USA100 (
n
= 1), USA400 (
n
= 5), and USA500 (
n
= 6). Among the CA-MRSA infection isolates, 8 (67%) were PVL
+
. None of the MRSA or MSSA isolates contained
arcA
or
opp3
. Only one MRSA isolate was USA300 by PFGE. This was a health care-associated (HA) MRSA isolate, negative for PVL, that carried SCC
mec
type II. USA300 with its characteristic features was not identified in the collection from the years 1994 to 1997.
Rapid High-Resolution Melt Analysis of Cytauxzoon felis CytochromebTo Aid in the Prognosis of Cytauxzoonosis
Authors: Schreeg Megan E. , Marr Henry S. , Tarigo Jaime L. , Cohn Leah A. , Levy Michael G. , Birkenheuer Adam J.
Published: May 2015

Cytauxzoon felisis a virulent, tick-transmitted, protozoan parasite that infects felines. Cytauxzoonosis was previously thought to be uniformly fatal in domestic cats. Treatment combining atovaquone and azithromycin (A&A) has been associated with survival rates of over 60%. Atovaquone, a ubiquinone analogue, targetsC. feliscytochromeb(cytb), of which 30 unique genotypes have been identified. TheC. feliscytbgenotypecytb1is associated with increased survival rates in cats treated with A&A. The purpose of this study was to design a PCR panel that could distinguishC. felis cytb1from other cytochromebgenotypes. Primer pairs were designed to span five different nucleotide positions at which single-nucleotide polymorphisms in theC. felis cytbgene had been identified. Through the use of high-resolution melt analysis, this panel was predicted to distinguishcytb1from othercytbgenotypes. Assays were validated using samples from 69 cats with cytauxzoonosis for which theC. felis cytbgenotypes had been characterized previously. The PCR panel identifiedC. felis cytb1with 100% sensitivity and 98.2% specificity. High-resolution melt analysis can rapidly provide prognostic information for clients considering A&A treatment in cats with cytauxzoonosis.
Nonglycosylated G-Protein Vaccine Protects against Homologous and Heterologous Respiratory Syncytial Virus (RSV) Challenge, while Glycosylated G Enhances RSV Lung Pathology and Cytokine Levels
Authors: Fuentes Sandra , Coyle Elizabeth M. , Golding Hana , Khurana Surender
Published: May 2015

New efforts are under way to develop a vaccine against respiratory syncytial virus (RSV) that will provide protective immunity without the potential for vaccine-associated disease enhancement such as that observed in infants following vaccination with formalin-inactivated RSV vaccine. In addition to the F fusion protein, the G attachment surface protein is a target for neutralizing antibodies and thus represents an important vaccine candidate. However, glycosylated G protein expressed in mammalian cells has been shown to induce pulmonary eosinophilia upon RSV infection in a mouse model. In the current study, we evaluated in parallel the safety and protective efficacy of the RSV A2 recombinant unglycosylated G protein ectodomain (amino acids 67 to 298) expressed inEscherichia coli(REG) and those of glycosylated G produced in mammalian cells (RMG) in a mouse RSV challenge model. Vaccination with REG generated neutralizing antibodies against RSV A2 in 7/11 BALB/c mice, while RMG did not elicit neutralizing antibodies. Total serum binding antibodies against the recombinant proteins (both REG and RMG) were measured by surface plasmon resonance (SPR) and were found to be >10-fold higher for REG- than for RMG-vaccinated animals. Reduction of lung viral loads to undetectable levels after homologous (RSV-A2) and heterologous (RSV-B1) viral challenge was observed in 7/8 animals vaccinated with REG but not in RMG-vaccinated animals. Furthermore, enhanced lung pathology and elevated Th2 cytokines/chemokines were observed exclusively in animals vaccinated with RMG (but not in those vaccinated with REG or phosphate-buffered saline [PBS]) after homologous or heterologous RSV challenge. This study suggests that bacterially produced unglycosylated G protein could be developed alone or as a component of a protective vaccine against RSV disease.

IMPORTANCENew efforts are under way to develop vaccines against RSV that will provide protective immunity without the potential for disease enhancement. The G attachment protein represents an important candidate for inclusion in an effective RSV vaccine. In the current study, we evaluated the safety and protective efficacy of the RSV A2 recombinant unglycosylated G protein ectodomain produced inE. coli(REG) and those of glycosylated G produced in mammalian cells (RMG) in a mouse RSV challenge model (strains A2 and B1). The unglycosylated G generated high protective immunity and no lung pathology, even in animals that lacked anti-RSV neutralizing antibodies prior to RSV challenge. Control of viral loads correlated with antibody binding to the G protein. In contrast, the glycosylated G protein provided poor protection and enhanced lung pathology after RSV challenge. Therefore, bacterially produced unglycosylated G protein holds promise as an economical approach to a protective vaccine against RSV.