bluuebunny/crossref_metadata_2025 huggingface dataset:
A biomechanical model of feeding kinematics forDunkleosteus terrelli(Arthrodira, Placodermi)
Authors: Anderson Philip S. L. , Westneat Mark W.
Published: April 2009

Biomechanical models illustrate how the principles of physics and physiology determine function in organisms, allowing ecological inferences and functional predictions to be based on morphology. Dynamic lever and linkage models of the mechanisms of the jaw and skull during feeding in fishes predict function from morphology and have been used to compare the feeding biomechanics of diverse fish groups, including fossil taxa, and to test ideas in ecological morphology. Here we perform detailed computational modeling of the four-bar linkage mechanism in the skull and jaw systems ofDunkleosteus terrelli, using software that accepts landmark morphological data to simulate the movements and mechanics of the skull and jaws during prey capture. The linkage system is based on the quadrate and cranio-thoracic joints: Cranial elevation around the cranio-thoracic joint forces the quadrate joint forward, which, coupled with a jaw depressor muscle connecting the jaw to the thoracic shield, causes the jaw to rotate downward during skull expansion. Results show a high speed transmission for jaw opening, producing a rapid expansion phase similar to that in modern fishes that use suction during prey capture. During jaw closing, the model computes jaw and skull rotation and a series of mechanical metrics including effective mechanical advantage of the jaw lever and kinematic transmission of the skull linkage system. Estimates of muscle cross-sectional area based on the largest of five specimens analyzed allow the bite force and strike speed to be estimated. Jaw-closing muscles ofDunkleosteuspowered an extraordinarily strong bite, with an estimated maximal bite force of over 6000 N at the jaw tip and more than 7400 N at the rear dental plates, for a large individual (10 m total length). This bite force capability is among the most powerful bites in animals. The combination of rapid gape expansion and powerful bite meant thatDunkleosteus terrellicould both catch elusive prey and penetrate protective armor, allowing this apex predator to potentially eat anything in its ecosystem, including other placoderms.
Hadrosaurid migration: inferences based on stable isotope comparisons among Late Cretaceous dinosaur localities
Authors: Fricke Henry C. , Rogers Raymond R. , Gates Terry A.
Published: April 2009

Stable carbon and oxygen isotope ratios were measured for carbonate in samples of hadrosaurid tooth enamel and dentine, and gar scale ganoine and dentine from five geologically “contemporaneous“ (two-million-year resolution) and geographically distant late Campanian formations (Two Medicine, Dinosaur Park, Judith River, Kaiparowits, and Fruitland) in the Western Interior Basin. In all cases, isotopic offsets were observed between enamel and dentine from the same teeth, with dentine being characterized by higher and more variable carbon and oxygen isotope ratios. Isotopic offsets were also observed between gar ganoine and hadrosaur enamel in all sites analyzed. Both of these observations indicate that diagenetic overprinting of enamel isotope ratios did not entirely obfuscate primary signals. Decreases in carbon and oxygen isotope ratios were observed in hadrosaur enamel from east to west, and overlap in isotope ratios occurred only between two of the sampled sites (Dinosaur Park and Judith River Formations).

The lack of isotopic overlap for enamel among localities could be due to diagenetic resetting of isotope ratios such that they reflect local groundwater effects rather than primary biogenic inputs. However, the large range in carbon isotope ratios, the consistent taxonomic offsets for enamel/ganoine data, and comparisons of enamel-dentine data from the same teeth all suggest that diagenesis is not the lone driver of the signal. In the absence of major alteration, the mostly likely explanation for the isotopic patterns observed is that hadrosaurids from the targeted formations were eating plants and drinking waters with distinct isotopic ratios. One implication of this reconstruction is that hadrosaurids in the Late Cretaceous of the Western Interior did not migrate to an extent that would obscure local isotopic signatures.
Carbon Dioxide Fixation within Mine Wastes of Ultramafic-Hosted Ore Deposits: Examples from the Clinton Creek and Cassiar Chrysotile Deposits, Canada
Authors: Wilson Sasha , Dipple Gregory M. , Power Ian M. , Thom James M. , Anderson Robert G. , Raudsepp Mati , Gabites Janet E. , Southam Gordon
Published: April 2009

Carbon dioxide (CO2) is sequestered through the weathering and subsequent mineralization of the chrysotile mine tailings at Clinton Creek, Yukon Territory, and Cassiar, British Columbia, Canada. Accelerated weathering is attributed to a dramatic increase in surface area, which occurs during the milling of ore. We provide a detailed account of the natural process of carbon trapping and storage as it occurs at Clinton Creek and Cassiar, including mineralogy, modes of occurrence, methods of formation for carbonate alteration, light stable isotope geochemistry, and radiocarbon analysis. Powder X-ray diffraction data were used to identify weathering products as the hydrated magnesium carbonate minerals nesquehonite [MgCO3·3H2O], dypingite [Mg5(CO3)4 (OH)2·5H2O], hydromagnesite [Mg5(CO3)4(OH)2·4H2O], and less commonly lansfordite [MgCO3·5H2O]. Textural relationships suggest that carbonate precipitates formed in situ after milling and deposition of tailings. Samples of efflorescent nesquehonite are characterized by δ13C values between 6.52 and 14.36 per mil, δ18O values between 20.93 and 26.62 per mil, and F14C values (fraction of modern carbon) between 1.072 and 1.114, values which are consistent with temperature-dependent fractionation of modern atmospheric CO2 during mineralization. Samples of dypingite ± hydromagnesite collected from within 0.2 m of the tailings surface give δ13C values between −1.51 and +10.02 per mil, δ18O values between +17.53 and +28.40 per mil, and F14C values between 1.026 and 1.146, which suggests precipitation from modern atmospheric CO2 in a soil-like environment. Field observations and isotopic data suggest that hydrated magnesium carbonate minerals formed in two environments. Nesquehonite formed in an evaporative environment on the surface of tailings piles, and dypingite and hydromagnesite formed in the subsurface environment with characteristics similar to soil carbonate. In both cases, these minerals have been trapping and storing the greenhouse gas, CO2, directly from the atmosphere. Combined use of δ13C, δ18O, and F14C data has been applied effectively as a tool for verifying and monitoring sequestration of atmospheric CO2 within mine tailings. A number of other deposit types produce tailings suitable for CO2 sequestration, including Cu-Ni-PGE deposits, diamondiferous kimberlite pipes, and podiform chromite deposits. Our results suggest that conversion of about 10 wt percent of tailings to carbonate minerals could offset the greenhouse gas emissions from many ultramafic-hosted mining operations.
A Critical Review for Proper Use of Water/Oil/Gas Transfer Functions in Dual-Porosity Naturally Fractured Reservoirs: Part I
Authors: Ramirez B. , Kazemi H. , Al-Kobaisi M. , Ozkan E. , Atan S.
Published: April 2009

Accurate calculation of multiphase-fluid transfer between the fracture and matrix in naturally fractured reservoirs is a crucial issue. In this paper, we will present the viability of the use of simple transfer functions to account accurately for fluid exchange resulting from capillary, gravity, and diffusion mass transfer for immiscible flow between fracture and matrix in dual-porosity numerical models. The transfer functions are designed for sugar-cube or match-stick idealizations of matrix blocks.

The study relies on numerical experiments involving fine-grid simulation of oil recovery from a typical matrix block by water or gas in an adjacent fracture. The fine-grid results for water/oil and gas/oil systems were compared with results obtained with transfer functions. In both water and gas injection, the simulations emphasize the interaction of capillary and gravity forces to produce oil, depending on the wettability of the matrix.

In gas injection, the thermodynamic phase equilibrium, aided by gravity/capillary interaction and, to a lesser extent, by molecular diffusion, is a major contributor to interphase mass transfer. For miscible flow, the fracture/matrix mass transfer is less complicated because there are no capillary forces associated with solvent and oil; nevertheless, gravity contrast between solvent in the fracture and oil in the matrix creates convective mass transfer and drainage of oil.

Using the transfer functions presented in this paper, fracture-and matrix-flow calculations can be decoupled and solved sequentially—reducing the complexity of the computation. Furthermore, the transfer-function equations can be used independently to calculate oil recovery from a matrix block.
A New Azimuthal Deep-Reading Resistivity Tool for Geosteering and Advanced Formation Evaluation
Authors: Bittar M. , Klein J. , Beste R. , Hu G. , Wu M. , Pitcher J. , Golla C. , Althoff G. , Sitka M. , Minosyan V. , Paulk M.
Published: April 2009

Drilling services and oil companies have long been interested in acquiring the capability of landing a well accurately in a hydrocarbon reservoir and remaining in it for optimal drainage. Although traditional logging-while-drilling (LWD) propagation resistivity tools can help to achieve this goal, their overall effectiveness is not satisfactory because they lack azimuthal sensitivity. Ideally, geosteering and advanced formation-evaluation methods, such as anisotropy calculations, require azimuthally sensitive measurements.

This paper discusses a newly developed propagation resistivity tool that is designed to be azimuthally sensitive for use in geosteering and formation evaluation while drilling. It uses the tilted-antenna concept to produce directionally sensitive measurements that are lacking in traditional LWD propagation tools. This paper also discusses the theory and the development of this tool, as well as the experimentation and numerical-modeling data used to characterize its azimuthal capability. Advanced application algorithms used to calculate the horizontal and the vertical resistivity (anisotropy calculation), as well as dipping angle, will be explained in detail. Finally, the paper presents and discusses field examples to demonstrate that this newly developed tool is a two-in-one service: geosteering and advanced formation evaluation.

The azimuthal deep-reading resistivity is shown to bear promise for use in optimization of well trajectory and well placement and in advanced formation evaluation while drilling. This newly developed tool is superior to traditional propagation tools in locating bed boundaries and in keeping the well in the desired pay zone. In addition to providing traditional multiple-depth-of-investigation resistivity measurements, this new tool provides multiple-depth-of-investigation azimuthal resistivity measurements.
Dry Gas Reinjection in a Strong Waterdrive Gas/Condensate Field Increases Condensate Recovery—Case Study: The Sleipner Øst Ty Field, South Viking Graben, Norwegian North Sea
Authors: Eikeland Kjersti M. , Hansen Helga
Published: April 2009

The Sleipner Øst Ty field is a strong waterdrive gas/condensate field, with in-place volumes of 59×109Sm3 dry gas and 52×10 Sm unstabilized condensate. The reservoir consists of deepwater turbidite sandstones and associated mudstones, which act as baffles to flow. The reservoir qualities are very good, with high porosity and permeability in the range of 100 to 1,000 md.

The first production in the area began at the Sleipner Øst Ty field in 1993. The initial reservoir pressure of 244 bar (2.44 × 104 kPa) is only a few bar above the dewpoint pressure. Massive dry-gas reinjection started in 1996, and the reservoir pressure increased during the next two years, which caused an increase in the condensate-to-gas ratio. During the injection period, which lasted until 2005, 29× 109Sm3 of dry gas was injected. The main focus during these years was to obtain good vertical and areal sweep of the dry gas in order to vaporize the dropped-out condensate. Chemical gas tracers were injected and analyzed for in the production wells to monitor the movement of the dry gas through the reservoir. This knowledge was used to identify unswept areas, and to change the drainage pattern by conducting well interventions and drilling infill wells.

The injection was stopped primarily because of high probability of trapping gas. Compositional reservoir simulation showed that from 10 to 20% of the injected dry-gas volume could be trapped in the northern region, which has no producers. The risk of not being able to back-produce the injected dry gas was considered high, since the saddle area separating the producers in the south from the injectors in the north was invaded by the aquifer.

The gas cycling program has increased the condensate recovery factor substantially; from the originally planned 50% by pressure depletion, to the current estimated ultimate recovery of 81%. As of July 2007, the condensate recovery factor was 76%.
Estimation of Fracture Porosity of Naturally Fractured Reservoirs With No Matrix Porosity Using Fractal Discrete Fracture Networks
Authors: Kim Tae H. , Schechter David S.
Published: April 2009

Matrix porosity is relatively easy to measure and estimate compared to fracture porosity. On the other hand, fracture porosity is highly heterogeneous and very difficult to measure and estimate. When matrix porosity of naturally fractured reservoirs (NFRs) is negligible, it is very important to know fracture porosity to evaluate reservoir performance. Because fracture porosity is highly uncertain, fractal discrete fracture network (FDFN) generation codes were developed to estimate fracture porosity. To reflect scale-dependent characteristics of fracture networks, fractal theories are adopted. FDFN modeling technique enables the systematic use of data obtained from image log and core analysis for estimating fracture porosity. As a result, each fracture has its own fracture aperture distribution, so that generated FDFN are similar to actual fracture systems. The results of this research will contribute to properly evaluating the fracture porosity of NFRs where matrix porosity is negligible.
Estimation of In Vivo Water Content of the Stratum Corneum from Electrical Measurements
Authors: Johnsen Gorm Krogh , Martinsen Ø.G , Grimnes S
Published: April 2009

In vivowater content in the epidermal stratum corneum can be estimated by means of low frequency susceptance measurements. In thein vitrocalibration necessary to find thein vivowater content, the stratum corneum will have a uniform distribution of water across its thickness. However,in vivostratum corneum has an increasing water concentration profile from the outermost towards the innermost parts. This paper will investigate the possibility of estimating the equilibrium water content in thein vivostratum corneum non-invasively from electrical susceptance measurements. Given a known shape of the water concentration profile in thein vivostratum corneum and the dependence of susceptance on the water content, it is possible to calculate the water contentin vivobased on analytically derived expressions for the water concentration profile. A correspondence betweenin vivoandin vitrowater content needed for this purpose is also established.
A Pictorial Technique for Mass Screening of Sorghum Germplasm for Anthracnose (Colletotrichum sublineolum) Resistance
Authors: Prom Louis K. , Perumal Ramasamy , Erpelding John , Isakeit Thomas , Montes-Garcia Noe , Magill Clint W.
Published: April 2009

Globally, the foliar phase of anthracnose is one of the most destructive diseases of sorghum. In most cases,
anthracnose resistance screening relies on the use of a spore suspension. This method is usually conducted after sundown
and when there is the possibility of dew formation the following morning. Using a spore suspension for sorghum
anthracnose field evaluation in College Station, Texas over five years (1996, 1997, 1999-2001) yielded inconsistent
linkage results and failed to identify any closely linked molecular markers. For large scale screening of sorghum
germplasm for anthracnose (Colletotrichum sublineolum) resistance, plants are inoculated in the field or in the green
house at either 30 d after planting or at the 8-10 leaf-stage. In field inoculation, the use of C. sublineolum-colonized
sorghum grains was shown to be the most efficient and effective in identifying resistant sources. For effective, efficient,
fast and accurate infection, approximately 10-20 seeds are placed in each plant leaf whorl and it takes about 16.7 kg of
colonized grains to cover a 0.4 ha area. In the greenhouse, though colonized grains are equally effective, spray inoculation
is preferred for easy and uniform coverage. Using this method of inoculum preparation, spore suspension was extracted
and sprayed (106 conidia·ml-1), followed by 10 hr/d misting for 30 sec at 30-45 min interval continuously for a period of
one month resulted in effective infection.
Creating Diversity in a Baccalaureate Nursing Program: A Case Study
Authors: Barton Amanda J. , Swider Susan M
Published: April 2009

Minority groups in the United States experience disparity in the health care services they receive and in their health related outcomes. Minority healthcare providers are more likely to serve minority under-served populations, thus addressing this healthcare disparity in an effective culturally competent manner (Robert Wood Johnson 2005; Sullivan, 2004). The purpose of the project was to increase the number of racial and ethnic minority students who are successfully recruited and admitted to the nursing program at Hope College in Holland, Michigan. The project involved the identification of perceived barriers to increased minority participation in nursing at the college, review of the literature to identify evidence-based interventions, and implementation of selected interventions to overcome the identified barriers. Implementation and evaluation are still on-going but showing early success.
Cultural divergence and performance evaluation systems: A comparative study of three Serbian companies
Authors: Bogicevic-Milikic Biljana , Janicijevic Nebojsa
Published: April 2009

Many authors have argued that human resource systems are the business practices most likely to be affected by the cultural context within which they are applied. Among other HRM practices cultural differences significantly affect performance evaluation, causing various difficulties and inefficiencies in the implementation of performance evaluation systems (PES). In order to provide for a deeper understanding of difficulties in the implementation of PES within specific cultural contexts, this paper therefore intends to explore the design and implementation of performance evaluation systems in three Serbian companies. The research findings point out the importance of building more culturally sensitive PES, calling attention to some possible directions, particularly in Serbia.
How to join the World Trade Organization: Some aspects of the accession process
Authors: Markovic Ivan
Published: April 2009

The World Trade Organization is the first international organization responsible for supervising global trade relations. It was established on January 1st 1995. The most important bodies of its organizational structure are the Ministerial Conference, the General Council and the Secretariat. It currently has 153 Members with many candidates involved in accession negotiations. Accession to the World Trade Organization is a highly organized process which can be divided into several steps or stages. The successful fulfillment of the conditions of one stage is the condition for movement to the next. Many challenges and opportunities are incorporated in that process and it is up to candidates for the Membership to find a way to face the challenges and use the opportunities.
Analysis of shocks affecting Europe: EMU and some central and eastern acceding countries
Authors: Ben Arfa
Published: April 2009

This paper deals with the synchronization of business cycles and economic shocks between the euro area and acceding countries. We therefore extract the business cycle component of output by using Hodrick-Prescott filter. Supply and demand shocks are recovered from estimated structural VAR models of output growth and inflation using long run restriction (Blanchard and Quah). We then check the (A) symmetry of these shocks by calculating the correlation between euro area shocks and those of the different acceding countries. We find that several acceding countries have a quite high correlation of demand shocks with the euro area however supply shocks are asymmetric; the correlation between euro area and central and east European countries (CEECs) is negative. We therefore conclude that joining the European Monetary Union is not yet possible: central and east European countries have to make structural changes to join the European Monetary Union.
Seasonal co-integration: An extention of the Johansen and Schaumburg approach with an exclusion test
Authors: Tasseven Ozlem
Published: April 2009

In this paper, the Johansen and Schaumburg method for seasonal cointegration has been tried to be applied for testing an a priori hypothesized cointegrating money demand variable space. We aim to provide a comprehensive discussion of the significance of the variables in the long-run context as stationary relationships for both zero and bi-annual frequencies. For this purpose, several restrictions have been used to impose for identification purposes of the relevant vectors. We also touch upon the possibility that most time series data have been subject to the stochastic seasonality as opposed to the general acceptance in empirical papers. Our results employing data from the Turkish economy show that it is not possible to estimate only a single theory-accepted money demand relationship in the long-run variable space for both zero and bi-annual frequences, but we are able to identify different vectors somewhat consistent with theoretical arguments for the annual frequency.
The search for co-integration between money, prices and income: Low frequency evidence from the Turkish economy
Authors: Saatçioğlu Cem , Korap Levent
Published: April 2009

In this paper, we aim to test the empirical validity of the QTM relationship for the Turkish economy. Using some contemporaneous time series estimation techniques, our estimation results reveal that stationarity characteristics of the velocities of currency in circulation and the broad money aggregate in the economy cannot be rejected through a quantity theoretical co-integrating long-term variable space. We find that there exists an about one-to-one proportionality between money and prices and money and real income, and that exogeneity of money cannot be rejected for the currency in circulation in the economy. But, the exception here comes from the broad monetary aggregate used in the QTM equation such that money seems to be endogenous as for the long-term variable space.
Long term dynamic of real exchange rate, trade liberalization and financial integration: The case of south-east Mediterranean countries
Authors: Amor Hadj , El Araj
Published: April 2009

The purpose of this paper is to estimate the effects of the trade liberalization and of the international financial integration on the long-term behavior of Real Exchange Rate (RER) for the South East Mediterranean countries. So the following question: how does the new trade and financial context affect the Equilibrium RER? We refer to the econometric technique of time series analysis, (the unit root tests of Dickey-Fuller (1979) and we apply the cointegration test of Engle and Granger (1987) of single equation for six South East Mediterranean countries (Algeria, Egypt, Lebanon, Morocco, Tunisia and Turkey) over the period of 1979-2004. Our estimates suggest that, for the six countries, long-term RER behavior depends essentially on economic specificity of each country and in particular on their degree of financial integration and trade opening. Our results also show that the evolution of the RER misalignment during our sample period, seem to be for some countries persistant and recurrent, but with decrease.
Challenges for monetary policy in the enlarged European monetary Union
Authors: Radovic Irena
Published: April 2009

The eastward enlargement of the Euro area entails significant implications for the accession candidates in Central and Eastern Europe (CEE), the existing Euro system and the monetary policy of the European Central Bank (ECB). The present analysis assesses the challenges and critical aspects in monetary policy modeling with special emphasis to enlargement. The focus is on the difficulty of implementing a unique currency policy in view or growing heterogeneity within the enlarged monetary union, and secondly - the issue of the voting mechanism within the ECB. When analyzing those two issues, it is conclusive that the difficulties for the ECB and the current Euro zone members will increase. For the enlarged Euro zone, which is becoming more divergent, it will be very hard to find adequate recipes to meet the needs and requirements of all. The big question is: whether centralization of monetary policy is a sustainable and superior solution?.
Projecting an Image: Film-Induced Festivals in the American West
Authors: Frost Warwick
Published: April 2009

Film and television are major forces in shaping destination image and encouraging tourism visitation. A growing literature reports on how film and television either directly attract tourists or are incorporated into destination marketing campaigns. However, there has been little research
examining how film and television may be used in festivals and events and how destinations may actively use such festivals as a medium for creating their destination image. This article considers film-induced festivals in the small American towns of Lone Pine and Jamestown. Both have been
extensively used as film locations since the 1920s, primarily for Westerns. Lone Pine has been the location for over 350 films, and Jamestown has been the location for 150 films. Through film-themed festivals, these towns have reshaped their destination images as idealized and romanticized
Western locales. In contrast, other aspects of their heritage have been downplayed, causing some dissonance between stakeholders.
RV and Camping Shows: A Motivation-Based Market Segmentation
Authors: Barbieri Carla , Mahoney Edward , Palmer Robert
Published: April 2009

Consumer shows are widely used throughout the world by recreational organizations. Although their use is rampant, little empirical research has been completed to understand the motivations of visitors they attract. The main purpose of this study was to identify different segments of
visitors attending RV and camping shows based on the underlying dimensions of their motivations. A total of 411 attendees to four RV and camping shows conducted in Michigan during 2005 were surveyed. Factor analysis performed on the motivations for attendance showed five underlying dimensions
for show attendance while subsequent k-means cluster analysis distinguished five segments of visitors. Chi-square and ANOVA tests revealed that these market segments are significantly different regarding their purchase cycle stage, product usage, and show behavior. Recognition of different
types of show customers have important marketing implications, especially regarding customer retention and market development, which this article discusses.
Innovation in Pop Festivals by Cocreation
Authors: van Limburg Bob
Published: April 2009

Cocreation, the latest marketing development concept using experienced lead users, their companies, and their communities were the foundation of this study. Cocreation adds a new dimension into the marketing policy of a company, thus developing the ultimate product or service. The lead
user analysis method of von Hippel, involving three steps, was followed in order to do explorative research about applying cocreation within the multiday pop festival branch. First the trends within this branch were identified. The next steps were to locate the lead users and then to analyze
their experiences. Useful tools within this explorative research are communities, which are used to gain information of lead users. The experiences of lead users in the multiday pop festival branch showed the problems and needs in this branch. These findings are both scientific and practical.
The scientific contribution is the question for more research of cocreation stimulating environments. The other scientific finding is the quest for research in order to make the lead user a better lead user and so more of value to a firm. The practical contribution is the delivery of a seven-step
model festival managers can use to implement cocreation in their festival.
Comparing Perceptions of Event Management Curriculum: A Factor-Correspondence Analysis
Authors: Lee Kyong Mo , Lee Myong Jae , Kim Hee Jung
Published: April 2009

This study aims to provide some insights into the current status of event management curriculum in Korea as perceived by major stakeholders in event management higher education: industry professionals, students, and educators. Responses to 408 questionnaires were analyzed using factor-correspondence
analysis. The factor analysis finds three most important dimensions of event management curriculum: Event Planning & Operations, Event Sponsorship and Marketing, and Field Experiences. A correspondence analysis further exhibits the relationship between major stakeholders and the curriculum
factors. The implications for event management higher education are also presented.
Destination Selection Criteria: Key Success Factors Evolve and Dominate
Authors: Rompf Paul D. , Breiter Deborah , Severt Kimberly
Published: April 2009

Billions of dollars are spent annually on events that span a variety of genres. Furthermore, different types of events demonstrate their own unique goals and objectives. Physical and operational requirements may change by organizational size, budgetary constraints, and internal business policies. The importance of event type in the choice of a host destination is of considerable interest. Previous studies pertaining to destination selection criteria have focused on specific destination characteristics without taking into consideration the various event types. The current study investigated similarities and differences in destination selection criteria based on event type. The results provide evidence that event planners assign different levels of importance to destination selection criteria based on event type. The study compares results to previous studies that utilized the same methodology and data analysis approach. Over time, it appears there may be melding of importance for multiple destination criteria as a result of industry and global standards.
Deacylases—structure, function, and relationship to diseases
Authors: Wang Shuxian , Xing Xiaoke , Ma Jialin , Zheng Sihao , Song Qibin , Zhang Pingfeng
Published: April 2024

Reversible S‐acylation plays a pivotal role in various biological processes, modulating protein functions such as subcellular localization, protein stability/activity, and protein–protein interactions. These modifications are mediated by acyltransferases and deacylases, among which the most abundant modification is S‐palmitoylation. Growing evidence has shown that this rivalrous pair of modifications, occurring in a reversible cycle, is essential for various biological functions. Aberrations in this process have been associated with various diseases, including cancer, neurological disorders, and immune diseases. This underscores the importance of studying enzymes involved in acylation and deacylation to gain further insights into disease pathogenesis and provide novel strategies for disease treatment. In this Review, we summarize our current understanding of the structure and physiological function of deacylases, highlighting their pivotal roles in pathology. Our aim is to provide insights for further clinical applications.
Long-term effects of iopamidol as a contrast medium for computed tomography in Cloudy Catsharks Scyliorhinus torazame
Authors: Ito Takaomi , Furuya Masaru , Tanaka Toshiyuki , Yoshii Yusuke , Murata Mikito , Sasai Kazumi
Published: April 2024

Objective

The use of computed tomography (CT) in aquarium animals, including elasmobranchs, has increased dramatically. To take advantage of CT, contrast medium is used to enhance internal organs and provide contrast since elasmobranchs lack visceral fat. In this study, the contrast effects of iopamidol were examined for up to 260 days after intravenous administration to establish the time course of the CT values for the target organs in eight mature Cloudy Catsharks Scyliorhinus torazame.

Methods

A micro-CT system was used to measure the CT values of the designated region of interest in the target organs (ventricular cavity, kidneys, liver, gallbladder, ovarian follicles, uterine horn cavity) over time and the eggs laid, following administration of iopamidol (700 mg of iodine/kg).

Result

The CT values of the ventricular cavity and kidneys peaked at 30 min and showed low values after day 22. The CT values for the liver increased over time and peaked at day 200, whereas values for the gallbladder and ovarian follicles peaked on day 6, with the gallbladder showing a low value and the ovarian follicles still showing a high value on day 260. Computed tomography images with identifiable enhancement within bilateral uterine horns were followed from days 1 to 35. The mean and maximum CT values of yolk and jelly in eggs laid after day 30 were significantly higher than the values for eggs laid up to day 29; embryonic development was confirmed in 88.7% of the eggs.

Conclusion

There was no mortality or morbidity of the sharks during the experiment, indicating that the administration of iopamidol at 700 mg of iodine/kg did not result in any adverse effects for 260 days. This is the first study to describe the long-term contrast effects of iopamidol, thus contributing new information about the application of contrast studies in Cloudy Catsharks.

Abstract

Impact statement In elasmobranchs, which include species facing extinction, there is limited knowledge on diagnostic imaging of computed tomography (CT). Soft tissue organs require intravascular administration of a contrast medium for CT imaging, yet data on the contrast effects and duration have been unknown. In this study, conducting CT scans on a Cloudy Catshark over 260 days after contrast medium administration yielded practical new insights into the diagnostic imaging for elasmobranchs.
Breast density quantification in dual‐energy mammography using virtual anthropomorphic phantoms
Authors: Pacheco Gustavo , Castillo‐Lopez Jorge Patricio , Villaseñor‐Navarro Yolanda , Brandan María‐Ester
Published: April 2024

Purpose

Breast density is a significant risk factor for breast cancer and can impact the sensitivity of screening mammography. Area‐based breast density measurements may not provide an accurate representation of the tissue distribution, therefore volumetric breast density (VBD) measurements are preferred. Dual‐energy mammography enables volumetric measurements without additional assumptions about breast shape. In this work we evaluated the performance of a dual‐energy decomposition technique for determining VBD by applying it to virtual anthropomorphic phantoms.

Methods

The dual‐energy decomposition formalism was used to quantify VBD on simulated dual‐energy images of anthropomorphic virtual phantoms with known tissue distributions. We simulated 150 phantoms with volumes ranging from 50 to 709 mL and VBD ranging from 15% to 60%. Using these results, we validated a correction for the presence of skin and assessed the method's intrinsic bias and variability. As a proof of concept, the method was applied to 14 sets of clinical dual‐energy images, and the resulting breast densities were compared to magnetic resonance imaging (MRI) measurements.

Results

Virtual phantom VBD measurements exhibited a strong correlation (Pearson's ) with nominal values. The proposed skin correction eliminated the variability due to breast size and reduced the bias in VBD to a constant value of −2%. Disagreement between clinical VBD measurements using MRI and dual‐energy mammography was under 10%, and the difference in the distributions was statistically non‐significant. VBD measurements in both modalities had a moderate correlation (Spearman's = 0.68).

Conclusions

Our results in virtual phantoms indicate that the material decomposition method can produce accurate VBD measurements if the presence of a third material (skin) is considered. The results from our proof of concept showed agreement between MRI and dual‐energy mammography VBD. Assessment of VBD using dual‐energy images could provide complementary information in dual‐energy mammography and tomosynthesis examinations.
Fabrication of Size‐Coded Amphiphilic Particles with a Configurable 3D‐Printed Microfluidic Device for the Formation of Particle‐Templated Droplets
Authors: Akhtar Muhammad Usman , Sahin Mehmet Akif , Werner Helen , Destgeer Ghulam
Published: April 2024

Compartmentalizing an aqueous media into numerous nanoliter‐scale droplets has substantially improved the performance of amplification assays. Particle‐templated droplets or dropicles offer a user‐friendly workflow for creating uniform volume compartments upon simple mixing of reagents and particles using common laboratory apparatus. Amphiphilic shape‐coded particles are demonstrated to spontaneously hold aqueous droplets within hydrophilic cavities for multiplexed diagnostic assays. Here, a configurable 3D‐printed microfluidic device is proposed for the tunable fabrication of amphiphilic size‐coded particles. The device is configured with multiple outlet tubings of different diameters and photomasks of variable slit lengths to fabricate a wide range of size‐coded particles. a range of unique particle codes are fabricated using a single reconfigurable device. The cross‐sectional profile of the particles is further engineered by tuning the flow rate ratios of precursor streams to vary the inner and outer diameters of the particles and the thicknesses of the inner hydrophilic and outer hydrophobic layers. A range of cavity diameters and particle lengths enabled dropicle volumes of ≈1 nL to ≈30 nL. The fabricated particles are characterized by their ability to hold uniform droplet volumes and to orient themselves facing upward or sideways in a well plate based on their aspect ratios.
Solar Steam Generator with Divergent Microchannels for Highly Efficient and Salt‐Resistant Brine Evaporation
Authors: Choi Jihun , Jeon Sangmin
Published: April 2024

A novel solar steam generator featuring divergent microchannels (SSG‐DM) is developed via directional freezing of a polypyrrole (PPy)–cellulose nanofiber (CNF) suspension in an inverted frustum mold. Contrary to the conventional 3D SSGs characterized by random micropores (SSG‐RM), SSGs incorporating vertical microchannels (SSG‐VM), fabricated through directional freezing procedure, demonstrate increased evaporation performance due to enhanced water transport to the top surface. However, SSG‐VM manifests a limitation in the form of reduced salt resistance on its side surfaces where water transport is restricted. This issue is addressed by directional freezing of a PPy–CNF suspension in an inverted frustum mold, followed by freeze‐thawing gelation in an AlCl3 solution. The fabricated SSG features divergent microchannels that spanned from the bottom surface to the top and side surfaces, with a gradual increase in diameter. The evaporation rate of SSG‐DM is recorded at 2.42 kg m−2h−1 under 1‐sun illumination; this rate further increases to 15.73 kg m−2h−1 in the presence of a 4 m s−1 wind. Notably, SSG‐DM demonstrates excellent salt resistance in highly saline brine (10 wt%) under windy conditions (4 m s−1), whereas SSG‐RM and SSG‐VM are ineffective under the same conditions.
Safety Through Visibility: Tracing Hydrogen in Colors with Highly Customizable and Flexibly Applicable Supraparticle Additives
Authors: Reichstein Jakob , Groppe Philipp , Stockinger Nina , Cuadrado Collados Carlos , Thommes Matthias , Wintzheimer Susanne , Mandel Karl
Published: April 2024

The flammability of H2‐air mixtures demands timely detection and precise localization of H2 leakages to ensure safety and targeted maintenance measures in the anticipated hydrogen economy. Herein, H2 indicator supraparticles (SPs) are demonstrated that meet this demand by making H2 visible to the naked eye by a rapid (ir)reversible color change. Their toolbox‐like manufacturing from SiO2 nanoparticles (NPs), Pt NPs, and indicator dye molecules   via spray‐drying allows for engineering their structure, texture, and detection performance by systematically tuning their composition. It is demonstrated that decreasing the SiO2 NP size, increasing the Pt NP concentration, and adjusting the amount of dye molecules improve the SPs’ response times. This opens up the option for multidimensional customization of their detection performance. Furthermore, the toolbox of H2 indicator SPs containing the established resazurin system is expanded to other indicator dyes, which makes a color change and reversibility of choice feasible. H2 indicator SPs meet many of the target characteristics for H2 detectors, e.g., low limit of detection, cycle stability, and high selectivity. Moreover, the SPs’ particulate nature allows for their flexible application as an additive, e.g., in coatings or clothing, which enables the detection and localization of H2 leakages in relevant application scenarios.
Metasurface‐Empowered Quantum Photonics
Authors: Li Yangwu , Liu Wenwei , Li Zhancheng , Cheng Hua , Chen Shuqi
Published: April 2024

In recent decades, quantum information technologies have attracted significant attention and experienced rapid development due to their ultrafast processing speeds and high level of information security. A significant trend in this field of study involves the ongoing pursuit of integrating and miniaturizing quantum devices. Metasurfaces, which are artificially designed planar nanostructure arrays with versatile wavefront shaping capabilities, present a promising platform for the development of integrated photonic quantum devices by effectively controlling quantum light in multiple degrees of freedom. In this review, recent advances in the field of quantum photonics facilitated by metasurfaces, encompassing quantum light sources, manipulation and measurement of quantum states, and the intriguing functionalities of quantum metasurfaces, are summarized. Additionally, potential future directions for the advancement of quantum metasurfaces are discussed.
1 MW Peak‐Power Mamyshev Oscillator Started by a Passively Q‐Switched Microchip Laser
Authors: Gotti Riccardo , Carrà Luca , Pizzurro Sara , Piccinno Giuliano , Agnesi Antonio , Pirzio Federico
Published: April 2024

Ultrafast fiber lasers (UFLs) have become an attractive alternative to solid‐state lasers (SSL) due to their excellent beam quality, compactness, environmental stability, and easy thermal management. In the last decade, a significant research effort is spent to identify UFL architectures providing pulse energy, duration, and peak power comparable to those of complex and expensive, Ti:sapphire laser systems and semiconductor saturable absorber mirrors mode‐locked, Yb‐doped SSL. Lately, Mamyshev oscillators (MOs), relying on offset spectral filtering combined with nonlinear spectral broadening by self‐phase modulation, emerge as a promising solution and are rapidly becoming the state of the art for high energy/peak power UFLs based on large‐mode‐area (LMA) fibers. The focus of this work is the first demonstration of starting of the mode‐locking regime in an LMA MO with an affordable passively Q‐switched microchip laser. This solution was previously demonstrated only in low‐power MO based on single‐mode fibers, which are intrinsically easier to seed, if compared to high‐gain LMA UFLs, because of the lower amplified spontaneous emission noise floor. This starting technique in an easy‐to‐implement ring LMA MO at 1 μm is tested. The oscillator provides ≈50 nJ pulses at 12 MHz repetition rate with a minimum pulse duration of ≈50 fs after compression, resulting in MW peak power.
Molecular Determinant Underlying Selective Coupling of Primary G‐Protein by Class A GPCRs
Authors: Shen Qingya , Tang Xinyan , Wen Xin , Cheng Shizhuo , Xiao Peng , Zang Shao‐Kun , Shen Dan‐Dan , Jiang Lei , Zheng Yanrong , Zhang Huibing , Xu Haomang , Mao Chunyou , Zhang Min , Hu Weiwei , Sun Jin‐Peng , Zhang Yan , Chen Zhong
Published: April 2024

G‐protein‐coupled receptors (GPCRs) transmit downstream signals predominantly via G‐protein pathways. However, the conformational basis of selective coupling of primary G‐protein remains elusive. Histamine receptors H2R and H3R couple with Gs‐ or Gi‐proteins respectively. Here, three cryo‐EM structures of H2R‐Gs and H3R‐Gi complexes are presented at a global resolution of 2.6‐2.7 Å. These structures reveal the unique binding pose for endogenous histamine in H3R, wherein the amino group interacts with E2065.46 of H3R instead of the conserved D1143.32 of other aminergic receptors. Furthermore, comparative analysis of the H2R‐Gs and H3R‐Gi complexes reveals that the structural geometry of TM5/TM6 determines the primary G‐protein selectivity in histamine receptors. Machine learning (ML)‐based structuromic profiling and functional analysis of class A GPCR–G‐protein complexes illustrate that TM5 length, TM5 tilt, and TM6 outward movement are key determinants of the Gs and Gi/o selectivity among the whole Class A family. Collectively, the findings uncover the common structural geometry within class A GPCRs that determines the primary Gs‐ and Gi/o‐coupling selectivity.
Chromium‐Induced High Covalent Co–O Bonds for Efficient Anodic Catalysts in PEM Electrolyzer
Authors: Yan Qisheng , Feng Jie , Shi Wenjuan , Niu Wenzhe , Lu Zhuorong , Sun Kai , Yang Xiao , Xue Liangyao , Liu Yi , Li Youyong , Zhang Bo
Published: April 2024

The proton exchange membrane water electrolyzer (PEMWE), crucial for green hydrogen production, is challenged by the scarcity and high cost of iridium‐based materials. Cobalt oxides, as ideal electrocatalysts for oxygen evolution reaction (OER), have not been extensively applied in PEMWE, due to extremely high voltage and poor stability at large current density, caused by complicated structural variations of cobalt compounds during the OER process. Thus, the authors sought to introduce chromium into a cobalt spinel (Co3O4) catalyst to regulate the electronic structure of cobalt, exhibiting a higher oxidation state and increased Co–O covalency with a stable structure. In‐depth operando characterizations and theoretical calculations revealed that the activated Co–O covalency and adaptable redox behavior are crucial for facilitating its OER activity. Both turnover frequency and mass activity of Cr‐doped Co3O4 (CoCr) at 1.67 V (vs RHE) increased by over eight times than those of as‐synthesized Co3O4. The obtained CoCr catalyst achieved 1500 mA cm−2 at 2.17 V and exhibited notable durability over extended operation periods – over 100 h at 500 mA cm−2 and 500 h at 100 mA cm−2, demonstrating promising application in the PEMWE industry.