bluuebunny/crossref_metadata_2025 huggingface dataset:
Replication of chronic abnormal cartilage loading by medial meniscus destabilization for modeling osteoarthritis in the rabbit knee in vivo
Authors: Arunakul Marut , Tochigi Yuki , Goetz Jessica E. , Diestelmeier Bryce W. , Heiner Anneliese D. , Rudert James , Fredericks Douglas C. , Brown Thomas D. , McKinley Todd O.
Published: July 2013

Medial meniscus destabilization (MMD) is a surgical insult technique for modeling osteoarthritis (OA) by replicating chronic abnormal cartilage loading in animal joints in vivo. The present study aimed to characterize the immediate biomechanical effects (ex vivo) and short‐term histological consequences (in vivo) of MMD in the rabbit knee. In a compressive loading test, contact stress distribution in the medial compartment was measured in eight cadaver rabbit knees, initially with all major joint structures uninjured (Baseline), after MMD, and finally after total medial meniscectomy (TMM). Similarly, the effects on sagittal joint stability were determined in an anterior–posterior drawer test. These biomechanical (ex vivo) data indicated that both MMD and TMM caused significant (p < 0.001), distinct (>1.5‐fold) elevation of peak local contact stress in the medial compartment, while leaving whole‐joint stability nearly unchanged. Histological consequences in vivo were assessed in a short‐term (8‐week) survival series of MMD or TMM (five animals for each group), and both caused moderate cartilage degeneration in the medial compartment. The MMD insult, which is feasible through posterior arthrotomy alone, is as effective as TMM for modeling injurious‐level chronic abnormal cartilage loading in the rabbit knee medial compartment in vivo, while minimizing potential confounding effects from whole‐joint instability. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31:1555–1560, 2013.
A 10Be production‐rate calibration for the Arctic
Authors: YOUNG NICOLÁs E. , SCHAEFER JOERG M. , BRINER JASON P. , GOEHRING BRENT M.
Published: July 2013

We present a Baffin Bay 10Be production‐rate calibration derived from glacial deposits in western Greenland and Baffin Island, and test our results against published 10Be calibration datasets to develop an Arctic 10Be production rate. Our calibration comprises: (i) 10Be measurements from moraine boulders linked to a 14C‐dated moraine at Jakobshavn Isfjord in western Greenland, (ii) an independent and previously published 10Be production rate at Jakobshavn Isfjord and (iii) re‐measured 10Be concentrations from a Baffin Island calibration site that is included in the north‐eastern North America dataset. Combined, we calculate a sea‐level/high‐latitude 10Be production rate for the Baffin Bay region of 3.96 ± 0.07 atoms g−1 a−1 (Lal/Stone scaling model). After testing the Baffin Bay rate against calibration sites in Norway and north‐eastern North America, we calculate a more conservative Arctic production rate of 3.96 ± 0.15 atoms g−1 a−1. The Baffin Bay and Arctic 10Be production rates are indistinguishable from the north‐eastern North America 10Be production rate (3.91 ± 0.19 atoms g−1 a−1) and yield overall uncertainties of <2–3.7% (1σ). These production rates reduce systematic uncertainties in 10Be‐based chronologies of ice‐margin change and allow 10Be‐based chronologies to be more confidently compared with high‐resolution climate records, such as those from Greenland ice cores.
Mitigation of 3‐MCPD and glycidyl esters within the production chain of vegetable oils especially palm oil
Authors: Matthäus Bertrand , Pudel Frank
Published: July 2013

In 2007 the oil producing industry and the downstream food processing industry were worried by the announcement that fatty acid esters of 3‐MCPD and later in 2008 that glycidyl esters have been found in different types of vegetable oils after processing. The reason for the concern was that the German Federal Institute for Risk Assessment assumed in a first statement the complete degradation of the esters to free 3‐MCPD and glycidol both classified by the International Agency for Research on Cancer (IARC) as possible and probably, respectively, carcinogenic to humans. In the meantime a lot of research has been done on these heat‐induced compounds to mitigate their formation during oil processing and today the content in vegetable oils could be remarkably lower if all approaches were implemented. This paper summarizes the different mitigation strategies and shows their effect on lowering the amount of 3‐MCPD and glycidyl esters in refined vegetable oils.
Pressure‐viscosity behaviour and film thickness in elastohydrodynamic regime of lubrication of ionic liquids and other base oils
Authors: Fernández Josefa , Paredes Xavier , Gaciño Félix M. , Comuñas María J. P. , Pensado Alfonso S.
Published: July 2013

Viscosities at high pressures for 16 base oils (six polyolesters, three polyglycols, six ionic liquids and squalane) were used to analyze the influence of their chemical structure on the pressure‐viscosity coefficient, α. Comparisons with literature α values for vegetable bases (canola, soybean and jojoba oils) are also performed. For the molecular lubricants, we found trends that are coherent with the literature, whereas for ionic liquids (ILs), new trends were found. ILs based on tris(pentafluoroethyl)trifluorophosphate anion [FAP]−are those which present higher α values. The role of the lubricants in the central thickness in the isothermal elastohydrodynamic regime of lubrication was evaluated through the product η00.69 α0.56, η0 being the viscosity at 0.1 MPa. One of the [FAP]− ILs provides film thicknesses close to the polyglycols with similar viscosity. Bis(trifluoromethylsulfonyl)imide ILs and the shorter polypropyleneglycoldimethyl ethers are the lubricants that better avoid the changes on the film thicknesses with the temperature owing to a high viscosity index. Copyright © 2013 John Wiley & Sons, Ltd.
Relationship between the histological appearance of the portal vein and development of ischemic-type biliary lesions after liver transplantation
Authors: Farid Waqar R. R. , de Jonge Jeroen , Zondervan Pieter E. , Demirkiran Ahmet , Metselaar Herold J. , Tilanus Hugo W. , de Bruin Ron W. F. , van der Laan Luc J. W. , Kazemier Geert
Published: July 2013

Ischemic-type biliary lesions (ITBLs) are a major cause of morbidity after liver transplantation (LT). Their assumed underlying pathophysiological mechanism is ischemia/reperfusion injury of the biliary tree, in which the portal circulation has been proposed recently to have a role. The aim of this study was to investigate whether early histological changes, particularly in the portal vein, predispose patients to ITBLs. A case-control study of 22 LT recipients was performed through a retrospective assessment of more than 30 histological parameters in 44 intraoperative liver biopsy samples taken after cold ischemia (time 0) and portal reperfusion (time 1). Eleven grafts developed ITBLs requiring retransplantation (the ITBL group), and 11 matched controls had normally functioning grafts 11 years after LT on average (the non-ITBL group). Additionally, 11 liver biopsy samples from hemihepatectomies performed for metastases of colorectal cancer (CRC) were assessed similarly. Analyses showed no significant histological differences at time 0 between the ITBL and non-ITBL groups. However, the time 1 biopsy samples from the ITBL group showed smaller portal vein branches (PVBs) significantly more often than the samples from the non-ITBL group, which also showed persisting paraportal collateral vessels. Larger PVBs and paraportal collateral vessels were also found in the CRC group. A morphometric analysis confirmed these findings and showed that PVB measurements were significantly lower for the ITBL group at time 1 versus the ITBL group at time 0 and the non-ITBL and CRC groups (they were largest in the CRC group). Thus, the PVB dimensions decreased in the ITBL group in comparison with the time 0 biopsy samples, and they were significantly smaller at time 1 in comparison with the dimensions for the non-ITBL and CRC groups. In conclusion, a smaller PVB lumen size in postreperfusion biopsy samples from liver grafts, suggesting a relatively decreased portal blood flow, is associated with a higher incidence of ITBLs. These findings support recent clinical studies suggesting a possible pathophysiological role of portal blood flow in the oxygenation of the biliary tree after LT. Liver Transpl 19:1088-1098, 2013. © 2013 AASLD.
Optimal control problem for an insurance surplus model with debt liability
Authors: Wei FanCheng , Wu Lan , Zhou Dasheng
Published: July 2013

For an insurance company with a debt liability, they could make some management actions, such as reinsurance, paying dividends, and capital injection, to balance the profitability and financial bankruptcy. Our objective is to determine risk retention rate, dividend, and capital injection strategy so as to maximize the expected discounted dividends minus the discounted cost of capital injection until the time of ruin. We assume that the dividend payments and capital injection should occur with both fixed and proportional costs. We obtain explicit expressions of the optimal value functions as well as the corresponding optimal joint strategies by routine procedures in a comprehensive basic model using a new technique to solve the related equations. Our results show that whether recapitalizing is profitable or not depends on the costs of capital raising and that the firm injects capital only when the reserves are zero and recapitalizes to the optimal reserves level if the cost of external capital is low. Copyright © 2013 John Wiley & Sons, Ltd.
Effect of water‐assisted extrusion and solid‐state polymerization on the microstructure of PET/Clay nanocomposites
Authors: Dini Maryam , Mousavand Tahereh , Carreau Pierre J. , Kamal Musa R. , Ton‐That Minh‐Tan
Published: July 2013

An melt‐mixing process has been used to prepare Poly(ethylene terephthalate) (PET)/clay nanocomposites with high degree of clay delamination. In this method, steam was fed into a twin‐screw extruder (TSE) to reduce the PET molecular weight and to facilitate their diffusion into the gallery spacing of organoclays. Subsequently, the molecular weight (MW) reduction of the PET matrix due to hydrolysis by water was compensated by solid‐state polymerization (SSP). The effect of the thermodynamic compatibility of PET and organoclays on the exfoliated microstructure of the nanocomposites was also examined by using three different nanoclays. The dispersion of Cloisite 30B (C30B) in PET was found to be better than that of Nanomer I.28E (I28E) and Cloisite Na+. The effect of feeding rate and consequently residence time on the properties of PET nanocomposites was also investigated. The results reveal more delamination of organoclay platelets in PET‐C30B nanocomposites processed at low feeding rate compared to those processed at high feeding rate. Enhanced mechanical and barrier properties were observed in PET nanocomposites after SSP compared to the nanocomposites prepared by conventional melt‐mixing. POLYM. ENG. SCI., 54:1723–1736, 2014. © 2013 Society of Plastics Engineers
ENGLISH LANGUAGE PROFICIENCY AND TEST PERFORMANCE: AN EVALUATION OF BILINGUAL STUDENTS WITH THE WOODCOCK‐JOHNSON III TESTS OF COGNITIVE ABILITIES
Authors: Sotelo‐Dynega Marlene , Ortiz Samuel O. , Flanagan Dawn P. , Chaplin William F.
Published: July 2013

In this article, we report the findings of an exploratory empirical study that investigated the relationship between English Language Proficiency (ELP) on performance on the Woodcock‐Johnson Tests of Cognitive Abilities‐Third Edition (WJ III) when administered in English to bilingual students of varying levels of ELP. Sixty‐one second‐grade students, identified as Limited English Proficient, were recruited from a suburban public school district and were given the WJ III in addition to their annual state standardized assessment of ELP. The findings of this study provide evidence to support a linear, inverse relationship between ELP and performance on tests that require higher levels of English language development and mainstream cultural knowledge. The implications of the findings of the present study suggest that practitioners must consider an examinee's level of developmental language proficiency and cultural knowledge acquisition as continuous variables when determining the impact of such factors on test performance and evaluation regarding whether scores obtained from tests administered in English are indeed valid for interpretation.
FACTORS THAT PREDICT ELEMENTARY EDUCATORS’ PERCEPTIONS AND PRACTICE IN TEACHING SELF‐DETERMINATION
Authors: Cho Hyun‐Jeong , Wehmeyer Michael , Kingston Neal
Published: July 2013

Promoting self‐determination has been suggested as a means for students with disabilities to access the general curriculum. We surveyed 407 elementary educators to examine a) the effects of classroom setting and teaching self‐regulation strategies on the perceived importance and frequency of teaching self‐determination; and b) the severity level of student disability, teacher primary assignment, teaching experience, and classroom and school setting on self‐regulation instruction. Teaching experience and classroom setting predicted the use of self‐regulation strategies, but primary assignment, school setting, and student disability did not. Self‐regulation instruction predicted the frequency of teaching self‐determination, but neither it nor classroom setting predicted the perceived importance of teaching self‐determination. Limitations and implications of this study are discussed, and suggestions for future research are offered.
The psychological experience of living with head and neck cancer: a systematic review and meta‐synthesis
Authors: Lang Heidi , France Emma , Williams Brian , Humphris Gerry , Wells Mary
Published: July 2013

Objective

To summarise patients' experiences of head and neck cancer (HNC) by examining the findings of existing qualitative studies

Methods

We undertook a systematic review and meta‐synthesis of qualitative studies in 29 published articles using Noblit and Hare's ‘meta‐ethnography’ approach to synthesise findings. The inclusion criteria were primary qualitative studies, focusing on HNC patients' experience and an English abstract. Seven databases were systematically searched.

Results

The articles focused on the experience of having HNC, the experience of treatments and the role of information. Our synthesis identified six core concepts—uncertainty and waiting, disruption to daily life, the diminished self, making sense of the experience, sharing the burden and finding a path. People experienced significant disruption to normal daily activities, because of the physical and emotional effects of HNC and its treatment. Day‐to‐day challenges were compounded by social and existential changes and a palpable loss of the individual's sense of self and future. In order to find a way through the considerable uncertainty and daily challenge of living with and beyond HNC, patients made continual efforts to make sense of their experience. Supportive relationships with their social network, HNC peers and healthcare professionals were particularly important, but support following treatment completion was sometimes limited. Perceptions of the future were affected by whether they saw life as diminished, merely changed or even enhanced by the experience of cancer.

Conclusions

This review supports further specific research into these emerging themes and provides a context for future work, informing interventions to improve patients' experiences. Copyright © 2013 John Wiley & Sons, Ltd.
The impact of awareness of terminal illness on quality of death and care decision making: a prospective nationwide survey of bereaved family members of advanced cancer patients
Authors: Ahn Eunmi , Shin Dong Wook , Choi Jin Young , Kang Jina , Kim Dae Kyun , Kim Hyesuk , Lee Eunil , Hwang Kwan Ok , Oh Bumjo , Cho BeLong
Published: July 2013

Objects

We aimed to assess whether awareness of a terminal illness can affect care decision making processes and the achievement of a good death in advanced cancer patients receiving palliative care services.

Methods

Awareness of terminal illness at the time of palliative care service admission was assessed by the health care professionals during the routine initial comprehensive assessment process and was recorded in the national terminal cancer patient registry. A follow‐up nationwide bereavement survey was conducted, which contained questions regarding decision making processes and the Korean version of the Good Death Inventory.

Results

Among the 345 patients included in the final analysis, the majority (68.4%) of the patients were aware of the terminal illness. Awareness of the terminal illness tended to reduce discordances in care decision making (adjusted odds ratio = 0.55; 95% CI: 0.29–1.07), and increased the patients' own decision making when there were discordances between patients and their families (adjusted odds ratio = 3.79; 95% CI: 1.31–10.94). The Good Death Inventory score was significantly higher among patients who were aware of their terminal illnesses compared with those who were not (5.04 vs. 4.80; p = 0.013) and especially in the domains of ‘control over the future’ (5.18 vs. 4.04; p < 0.001), ‘maintaining hope and pleasure’ (4.55 vs. 3.92; p = 0.002), and ‘unawareness of death’ (4.41 vs. 4.26; p = 0.024).

Conclusion

Awareness of the terminal illness had beneficial effect on the harmonious decision making, patient autonomy, and patient's quality of death. Disclosure of terminal illness should be encouraged. Copyright © 2013 John Wiley & Sons, Ltd.
Aptamer‐Assisted Assembly of Gold Nanoframe Dimers
Authors: Combs Zachary A. , Malak Sidney T. , König Tobias , Mahmoud Mahmoud A. , Chávez Jorge L. , El‐Sayed Mostafa A. , Kelley‐Loughnane Nancy , Tsukruk Vladimir V.
Published: July 2013

The assembly of nanoframe dimers assisted by aptamer‐functionalized smaller spherical gold nanoparticles as prospective surface‐enhanced Raman scattering (SERS) biotraps for riboflavin, an important molecule for biological electron transfer reactions, is reported. In this approach, the aptamer‐coated gold nanoparticles designed for selective binding of riboflavin also serve as the electrostatic driver for nanoframe dimerization in dilute solutions. The gold nanoframe dimers provide unique conditions for plasmonic coupling in a hot spot with sufficient space for the binding of bulky biomolecules. The use of an aptamer allows for highly selective binding of the targeted analyte as compared with conventional organic ligands with excellent low detection limit of one micromole of riboflavin.
Structures, optical properties, and electrical transport processes of SnO2 films with oxygen deficiencies
Authors: Ji Yu‐Chen , Zhang Hua‐Xing , Zhang Xing‐Hua , Li Zhi‐Qing
Published: July 2013

The structures, optical and electrical transport properties of SnO2 films, fabricated by rf sputtering method at different oxygen partial pressures, were systematically investigated. It has been found that preferred growth orientation of SnO2 film is strongly related to the oxygen partial pressure during deposition, which provides an effective way to tune the surface texture of SnO2 film. All films reveal relatively high transparency in the visible range, and both the transmittance and optical band gap increase with increasing oxygen partial pressure. The temperature dependence of resisitivities was measured from 380 K down to liquid helium temperatures. At temperature above K, besides the nearest‐neighbor‐hopping process, thermal activation processes related to two donor levels ( and 100 meV below the conduction band minimum) of oxygen vacancies are responsible for the charge transport properties. Below K, Mott variable‐range hopping conduction process governs the charge transport properties at higher temperatures, while Efros–Shklovskii (ES) variable‐range‐hopping conduction process dominates the transport properties at lower temperatures. Distinct crossover from Mott type to ES type variable‐range‐hopping conduction process at several to a few tens kelvin are observed for all SnO2 films.
Use of 1,5‐diaminonaphthalene to combine matrix‐assisted laser desorption/ionization in‐source decay fragmentation with hydrogen/deuterium exchange
Authors: Lemaire Pascale , Debois Delphine , Smargiasso Nicolas , Quinton Loïc , Gabelica Valérie , De Pauw Edwin A.
Published: July 2013

RATIONALE

In‐Source Decay (ISD) in Matrix‐Assisted Laser Desorption/Ionization (MALDI) mass spectrometry is a fast and easy top‐down activation method. Our objective is to find a suitable matrix to locate the deuterons following in‐solution hydrogen/deuterium exchange (HDX). This matrix must circumvent the commonly encountered undesired back‐exchange reactions, in order to preserve the regioselective deuteration pattern.

METHODS

The 1,5‐diaminonaphthalene (1,5‐DAN) matrix is known to be suitable for MALDI‐ISD fragmentation. MALDI Mass Spectrometry Imaging (MSI) was employed to compare 1,5‐DAN and other commonly used MALDI matrices with respect to the extent of back‐exchange and the uniformity of the H/D exchange profiles within the MALDI spots. We tested the back‐exchange on the highly sensitive amyloid‐beta peptide (1‐40), and proved the regioselectivity on ubiquitin and β‐endorphin.

RESULTS

MALDI‐MSI results show that 1,5‐DAN leads to the least back‐exchange over all the spot. MALDI‐ISD fragmentation combined with H/D exchange using 1,5‐DAN matrix was validated by localizing deuterons in native ubiquitin. Results agree with previous data obtained by Nuclear Magnetic Resonance (NMR) and Electron Transfer Dissociation (ETD). Moreover, 1,5‐DAN matrix was used to study the H/D exchange profile of the methanol‐induced helical structure of β‐endorphin, and the relative protection can be explained by the polarity of residues involved in hydrogen bond formation.

CONCLUSIONS

We found that controlling crystallization is the most important parameter when combining H/D exchange with MALDI. The 1,5‐DAN matrix is characterized by a fast crystallization kinetics, and therefore gives robust and reliable H/D exchange profiles using MALDI‐ISD. Copyright © 2013 John Wiley & Sons, Ltd.
A SEM and non‐contact surface white light profilometry in vivo study of the effect of a crème containing CPP‐ACP and fluoride on young etched enamel
Authors: Baroni Chiara , Marchionni Silvia , Bazzocchi Maria Giulia , Cadenaro Milena , Nucci Cesare , Manton David J
Published: July 2013

The aim of this in vivo study was to evaluate the short and a longer term effect on enamel of the application of a crème containing 10% CPP‐ACP and 900 ppm fluoride, in orthodontically planned, high caries‐risk patients. Epoxy resin replicas of upper lateral incisors were obtained from polyvinyl siloxane (PVS) impressions, before and after etching. The right incisors were left untreated in order to control saliva remineralizing potential. The upper left surfaces were coated with a pea‐size amount of the crème. Replicas were obtained at 3 weeks and 6 months and analyzed by SEM and non‐contact surface white light profilometry. In the treated sample the profilometric roughness parameters at 3 weeks were statistically significantly lower than the control group values (p < 0.05). At 3 weeks SEM images of the enamel surface showed fewer irregularities. After 6 months, differences between test and control groups were not present on SEM images and profilometric values. CPP‐ACP and fluoride crème had positive in vivo effects on enamel surfaces. Significant differences in surface roughness existed after a 3‐week period of crème use. SCANNING 36:270–277, 2014. © 2013 Wiley Periodicals, Inc.
A secure authentication scheme for session initiation protocol by using ECC on the basis of the Tang and Liu scheme
Authors: Irshad Azeem , Sher Muhammad , Faisal Muhammad Shahzad , Ghani Anwer , Ul Hassan Mahmood , Ashraf Ch Shehzad
Published: July 2013

Session initiation protocol (SIP) provides the basis for establishing the voice over internet protocol sessions after authentication and exchanging signaling messages. SIP is one of the significant and extensively used protocols in the multimedia protocol stack. Since the RFC2617 was put forth, numerous schemes for SIP authentication have been presented to overcome the flaws. Recently, in 2012, Tang and Liu proposed SIP based authentication protocol and claimed for eliminating the threats in Arshad and Ikram protocol. However the scheme can be made more robust by making further improvements, as the former scheme may come under a threat by adversaries through impersonating a server, given that the user password is compromised. We have proposed an improved protocol for SIP authentication by using elliptic curve cryptography that encounters the previous threat with enhanced security. The analysis shows that proposed scheme is suitable for applications with higher security requirements. Copyright © 2013 John Wiley & Sons, Ltd.
An aggregated signature‐based fast RFID batch detection protocol
Authors: Li Chaoliang , Wang Guojun , Zheng Jin
Published: July 2013

The wireless channels between tags and readers are not secure in Internet of Things. Before a reader processes packets from tags, the reader should detect the integrity of these packets. In existing research, these packets are detected by readers one by one. This process is time‐consuming and impractical under some real‐time scenarios. To decrease the detection time, we propose a fast radio‐frequency identification batch detection protocol that is more suitable to detect whether the packets are modified by adversaries. The analysis and experimental results show that the proposed protocol has the following good properties: (i) it can detect the integrity of packets very fast; (ii) it has better performance in computational cost and storage cost of tags and servers; (iii) it can provide security protection in an efficient way. Copyright © 2013 John Wiley & Sons, Ltd.
A hybrid method in combining treatment effects from matched and unmatched studies
Authors: Byun Jinyoung , Lai Dejian , Luo Sheng , Risser Jan , Tung Betty , Hardy Robert J.
Published: July 2013

The most common data structures in the biomedical studies have been matched or unmatched designs. Data structures resulting from a hybrid of the two may create challenges for statistical inferences. The question may arise whether to use parametric or nonparametric methods on the hybrid data structure. The Early Treatment for Retinopathy of Prematurity study was a multicenter clinical trial sponsored by the National Eye Institute. The design produced data requiring a statistical method of a hybrid nature. An infant in this multicenter randomized clinical trial had high‐risk prethreshold retinopathy of prematurity that was eligible for treatment in one or both eyes at entry into the trial. During follow‐up, recognition visual acuity was accessed for both eyes. Data from both eyes (matched) and from only one eye (unmatched) were eligible to be used in the trial. The new hybrid nonparametric method is a meta‐analysis based on combining the Hodges–Lehmann estimates of treatment effects from the Wilcoxon signed rank and rank sum tests. To compare the new method, we used the classic meta‐analysis with the t‐test method to combine estimates of treatment effects from the paired and two sample t‐tests. We used simulations to calculate the empirical size and power of the test statistics, as well as the bias, mean square and confidence interval width of the corresponding estimators. The proposed method provides an effective tool to evaluate data from clinical trials and similar comparative studies. Copyright © 2013 John Wiley & Sons, Ltd.
Tunable Assembly of Gold Nanoparticles on Nanopatterned Poly(ethylene glycol) Brushes
Authors: Onses M. Serdar , Nealey Paul F.
Published: July 2013

The organization of metallic nanoparticles (NPs) into ordered arrays on nanopatterned surfaces is an enabling process to fabricate devices and study the properties of the particles. Tailoring the interaction between NPs and nanopatterns is a necessity to gain a high level of control in this process. Here, nanopatterned poly(ethylene glycol) (PEG) brushes are presented as a platform for the organization of Au NPs on surfaces. The binding of citrate‐stabilized Au NPs to the PEG brushes depends on the size of the particles and molecular weight of the brushes: the density of NPs immobilized on the nanopatterns of PEG brushes increases with decreasing the diameter of the particles and increasing the chain length of the brushes. The key aspect of the process is to pattern PEG brushes with high resolution and chemical contrast to provide controllable and specific interaction between Au NPs and nanopatterns at a single particle resolution. The modulation of the number (0–4) of Au NPs (e.g., 30 nm) per patterned feature with a high level of accuracy and the generation of patterned heterostructures that consist of two different sizes (e.g., 40 and 20 nm) of particles constitute two examples showing the capabilities of the presented platform.
Students' conceptual change in electricity and magnetism using simulations: A comparison of cognitive perturbation and cognitive conflict
Authors: Dega Bekele Gashe , Kriek Jeanne , Mogese Temesgen Fereja
Published: July 2013

The purpose of this study was to investigate Ethiopian physics undergraduate students' conceptual change in the concepts of electric potential and energy (EPE) and electromagnetic induction (EMI). A quasi‐experimental design was used to study the effect of cognitive perturbation using physics interactive simulations (CPS) in relation to cognitive conflict using physics interactive simulations (CCS). Data were collected by using the modified Diagnostic Exam of Electricity and Magnetism (DEEM). ANCOVA was conducted on the scores of 45 students on the modified DEEM test to compare the effectiveness of the CCS and CPS. The results showed a significant difference between the two classes of the post‐test scores on the DEEM test, (1, 36) = 4.66, p = 0.04, partial eta squared = 0.12. Consequently, it was concluded that there is a statistically significant difference between CPS and CCS in changing students' alternative conceptions towards scientific conceptions favoring CPS. Medium practical difference between the two classes was estimated by the partial eta squared effect size. To characterize and compare improvement of the students' conceptual learning in both treatment classes, Hake's average normalized gain 〈g〉 from pre‐ to post‐scores were analyzed. It is suggested that in abstract conceptual areas of electricity and magnetism, in which most students have inappropriate and counterproductive responses, cognitive perturbation through interactive simulations is more effective than cognitive conflict through interactive simulations in facilitating conceptual change, and, thus, can improve classroom instruction in the area. Recommendations are also suggested for guiding future research in this area. © 2013 Wiley Periodicals, Inc. J Res Sci Teach
How do students in an innovative principle‐based mechanics course understand energy concepts?
Authors: Ding Lin , Chabay Ruth , Sherwood Bruce
Published: July 2013

We investigated students' conceptual learning of energy topics in an innovative college‐level introductory mechanics course, entitled Matter & Interactions (M&I) Modern Mechanics. This course differs from traditional curricula in that it emphasizes application of a small number of fundamental principles across various scales, involving microscopic atoms, macroscopic deformable objects, and large‐scale planetary systems. To best match the unique features of this course, a multiple‐choice energy assessment was developed. We followed the development framework and explicitly delineated test purpose, scope, and specifications to guide the design, implementation and evaluation of the energy assessment. Also, particular attention was given to: (1) categorizing content and cognition levels and (2) determining reasoning steps of each test item—aspects that often were not explicitly addressed in designing prior concept assessments. We implemented the energy assessment as a written test before and after course instruction with M&I students at two research universities. Interviews were also conducted to explore students' reasoning in applying energy concepts. Results showed that positive change in student conceptual understanding after course instruction was significant on the entire assessment, on individual items, and on individual test objectives. Subsequent interviews further revealed that after instruction students could properly apply the Energy Principle and perform qualitative analysis without using formula sheets. However, students still showed difficulty in dealing with systems involving deformable objects. This study exemplifies practical means of establishing and evaluating key assessment features, provides evidence for the effectiveness of a principle‐focused approach to physics learning, and offers useful implications for teaching energy topics. © 2013 Wiley Periodicals, Inc. J Res Sci Teach 9999: 1–26, 2013
Multiscale image‐based modeling and simulation of gas flow and particle transport in the human lungs
Authors: Lin Ching‐Long , Tawhai Merryn H. , Hoffman Eric A.
Published: July 2013

Improved understanding of structure and function relationships in the human lungs in individuals and subpopulations is fundamentally important to the future of pulmonary medicine. Image‐based measures of the lungs can provide sensitive indicators of localized features, however to provide a better prediction of lung response to disease, treatment, and environment, it is desirable to integrate quantifiable regional features from imaging with associated value‐added high‐level modeling. With this objective in mind, recent advances in computational fluid dynamics (CFD) of the bronchial airways—from a single bifurcation symmetric model to a multiscale image‐based subject‐specific lung model—will be reviewed. The interaction of CFD models with local parenchymal tissue expansion—assessed by image registration—allows new understanding of the interplay between environment, hot spots where inhaled aerosols could accumulate, and inflammation. To bridge ventilation function with image‐derived central airway structure in CFD, an airway geometrical modeling method that spans from the model ‘entrance’ to the terminal bronchioles will be introduced. Finally, the effects of turbulent flows and CFD turbulence models on aerosol transport and deposition will be discussed. WIREs Syst Biol Med 2013, 5:643–655. doi: 10.1002/wsbm.1234

This article is categorized under:

Analytical and Computational Methods > Computational Methods

Models of Systems Properties and Processes > Organ, Tissue, and Physiological Models
Varied Layer Topologies in Luminescent Zinc Coordination Polymers with Flexible Aromatic ortho‐Dicarboxylate and Dipyridyl Ligands
Authors: Murray Nathan H. , Farnum Gregory A. , LaDuca Robert L.
Published: July 2013

Hydrothermal synthesis has afforded four divalent zinc flexible‐arm aromatic ortho‐dicarboxylate coordination polymers containing dipyridyl coligands. According to X‐ray crystallography, all four show layered coordination polymer structures. Nevertheless there is significant ligand influence on the nature of zinc atom aggregation and overall topology. In both {[Zn2(hmph)2(dpa)2]·2H2O}n (1) (hmph = homophthalate, dpa = 4, 4′‐dipyridylamine), and {[Zn2(hmph)2(dpe)2](ClO4)2·H2dpe·4H2O}n (2) [dpe = bis(4‐pyridyl)ethane], large {Zn2(hmph)2} dimeric units are evident, along with an overall herringbone (6, 3) layer topology. The longer span of the dpe ligands results in larger incipient channels, which can accommodate protonated dpe dications and perchlorate counterions. In {[Zn2(hmph)2(3‐pna)]·H2O}n (3) (3‐pna = 3‐pyridylnicotinamide), {Zn2(OCO)2} anti‐syn bridged dimers and {Zn2(OCO)4} syn‐syn paddlewheel dimers coexist and are linked together by hmph and 3‐pna ligands into decorated (4, 4) grid coordination polymer layers. {[Zn(1, 2‐phda)(3‐pina)]·2H2O}n (4) (1, 2‐phda = 1, 2‐phenylenediacetate, 3‐pina = 3‐pyridylisonicotinamide) manifests an undulating (4, 4) grid structure with isolated zinc atoms; the “wavelength” of the layers measures over 40 Å. Luminescent properties of these materials are also reported.
An Oxygen/Chlorine Double‐Capped Praseodymium Tetramer Cluster Complex with Thiazole
Authors: Dannenbauer Nicole , Müller‐Buschbaum Klaus
Published: July 2013

A tetramer cluster complex of the formula [Pr4Cl10(OH)2(thz)8(H2O)2] was prepared constituted by two edge sharing metal triangles coordinated by thiazole (thz) and chloride ligands bent together by opposing μ3‐hydroxide and chloride capping for both triangles. The tetramer is the first thiazole complex of a lanthanide ion and shows a previously unknown symmetric capping mode. It co‐crystallizes with an anhydrous dimeric complex of the formula [Pr2Cl6(thz)8] in equal amounts.
The New Homoleptic Tetracyanamidoaluminate LiBa2[Al(CN2)4]
Authors: Unverfehrt Leonid , Ströbele Markus , Meyer H.‐Jürgen
Published: July 2013

The new tetracyanamidoaluminate LiBa2[Al(CN2)4] was prepared by solid state metathesis reaction in a fused copper ampoule from a mixture of BaF2, AlF3, and Li2(CN2) at 550 °C. The crystal structure was solved and refined based on single‐crystal X‐ray diffraction data [P212121, Z = 4, a = 6.843(1) Å, b = 11.828(2) Å, c = 11.857(2) Å]. The compound belongs to the known formula type LiM2[Al(CN2)4] (M = Sr, Eu) containing the homoleptic [Al(CN2)4]5– ion. However, LiBa2[Al(CN2)4] forms a distinct crystal structure, containing a two‐dimensional [(NCN)2/2Li(NCN)2Al(NCN)2/2] network with four‐coordinate Li+ and Al3+ ions. Two crystallographically independent Ba2+ ions are situated in eightfold environment of terminal nitrogen atoms of cyanamide ions.
Groundwater Flow Modelling of Hindon-Yamuna Interfluve Region, Western Uttar Pradesh
Authors: Alam Fakhre , Umar Rashid
Published: July 2013

The study area Hindon -Yamuna interfluve region is underlain by a thick pile of unconsolidated Quaternary alluvial deposits and host multiple aquifer system. Excessive pumping in the last few decades, mainly for irrigation, has resulted in a significant depletion of the aquifer. Therefore, proper groundwater management of Hindon-Yamuna interfluve region is necessary. For effective groundwater management of a basin it is essential that careful zone budget study should be carried out. Keeping this in view, groundwater flow modelling was attempted to simulate the behavior of flow system and evaluate zone budget. Visual MODFLOW, pro 4.1 is used in this study to simulate groundwater flow. The model simulates groundwater flow over an area of about 1345 km2 with a uniform grid size of 1000 m by 1000 m and contains three layers, 58 rows and 37 columns. The horizontal flows, seepage losses from unlined canals, recharge from rainfall and irrigation return flows were applied using different boundary packages available in Visual MODFLOW, pro 4.1. The river – aquifer interaction was simulated using the river boundary package. Simulated pumping rates of 500 m3/day, 1000 m3/day and 1500 m3/day were used in the pumping well package. The zone budget for the steady state condition of study area indicated that the total annual direct recharge is 416.10 MCM and the total annual groundwater draft through pumping is of the order of 416.63 MCM. Two scenarios were considered to predict aquifer system response under different conditions. Sensitivity analysis on model parameters was conducted to quantitatively evaluate the impact of varying model inputs. Based on the results obtained from the sensitivity analysis, it was found that the model is more sensitive to hydraulic conductivity and recharge parameter. Present study deals with importance of groundwater modelling for planning, design, implementation and management of groundwater resources.
A New Occurrence of Sapphirine-Spinel-Corundum-bearing Granulite from NE of Jagtiyal, Eastern Dharwar Craton, Andhra Pradesh
Authors: Prakash D. , Singh P. Chandra , Hokada T.
Published: July 2013

We report a new occurrence of sapphirine-spinel-corundum bearing granulites enclosed in granitic gneisses near Jagtiyal in the Eastern Dharwar Craton (EDC). These granulites are very important in deciphering the prehistory of the thermal peak of metamorphism due to the presence of refractory phases. The appearance of sapphirine is related to the following reactions: (a) Spl1 + Crd1 = Spr1 (2:2:1) (b) Phl (in Bt1) + Crn1 = East (in Bt2) + Spr2 (7:9:3) + Crd2 (c) Bt2 + Crd1 +Crn1 = Spr2 (7:9:3) + Kfs + H2O (d) Crd1 + Spl1 + Crn1 = Spr2 (7:9:3). The P–T evolution of these sapphirine granulites has been constrained through the use of THERMOCALC program. Temperature of formation of sapphirine-spinel assemblages is high, around 800 °C, and pressure ranges from 5-7 kbars, suggesting that sapphirine formation took place during decompression stage.
Mineral Chemistry of Clays Associated with the Jhilmili Intertrappean Bed in the Eastern Deccan Volcanic Province: Palaeoenvironmental Inferences and KTB Transition
Authors: Pal Sucharita , Srivastava Surabhi , Shrivastava J. P.
Published: July 2013

Jhilmili intertrappean bed (~13 m thick) attains its significance with the recent discovery of brackish water ostrocod and planktonic foraminifera fossils (Keller et al. 2009; Khosala et al. 2009). Present XRD data revealed abundance of montmorillonite > montmorillonite/chlorite mixed layer > palygorskite in five physically distinct litho-units namely: (a) lower chocolate brown siltstone with green patches, followed by (b) brick red clayey siltstone, (c) greenish grey clay, (d) yellowish brown clay and (e) uppermost olive grey to dark brown silt layers in the succession-represent higher weathering indices and annual precipitation, reflecting cyclic, but longer spells of weathering. Occurrence of M/C mixed layer with the smectite in Jhilmili area is suggestive of their derivation from the later, whilst montmorillonite to palygorskite transformation is ascribed to the drastic changes in the humid to arid climate, where former served as a source of Al and some of the Si and Mg ions for the later. Jhilmili and Anjar clays represent similar charge occupancies at different sites, but later contains relatively higher amount of palygorskite, formed in the arid environment. Majority of the trace elemental data plots for Jhilmili clays lie within the upper and lower limits of infra (Lametas)-/inter-trappeans clays. The continuous release of Cu throughout the succession (mainly in the palygorskite dominated clays) indicates oxidizing conditions. PAAS normalized REE data plots for these clays show progressive enrichment in the HREE contents in the lower part, but, upper part of the succession is marked by positive cerium anomaly, reflecting oxidizing conditions prevailed at the later stage of the succession. These conditions continued, but, were not conducive to HREE enrichment as evidenced by their depletion in the upper part of the succession. The Ce anomaly observed in the middle part of the succession is similar to that form by continental weathering of the basalt, ascribed to Ce precipitation in the oxic environment, thus suggestive of drastic changes in the oxidizing conditions. Thermodynamic data-sets for Jhilmili clays show I/S mixed layer and celadonite compositions, whereas, Jabalpur infra-/inter-trappean clays correspond to Mg smectites and celadonite end members, thus, representing compositional commonality with those of the other clays derived from the continental weathering of basalt protolith. Jhilmili smectites and smectite-chlorite mixtures show compositional similarity with the dioctahedral and trioctahedral smectites and the smectites formed at 250ºC, having compositions between trioctahedral smectite and chlorite, thus, assigning high temperatures for their formation, where the heat required for the formation of these clays was possibly derived from the hydrothermal fluids, associated with the Deccan volcanism.
Cognitive schemes and strategies in diagnostic and therapeutic decision making: a
primer for trainees
Authors: Hassan Imad Salah Ahmed
Published: July 2013

Cost analyses in medical education are rarely straightforward, and rarely lead to
clear-cut conclusions. Occasionally they do lead to clear conclusions but even when that
happens, some stakeholders will ask difficult but valid questions about what to do
following cost analyses–specifically about distributive justice in the allocation of
resources. At present there are few or no debates about these issues and rationing
decisions that are taken in medical education are largely made subconsciously.
Distributive justice ‘concerns the nature of a socially just allocation of goods in a
society’. Inevitably there is a large degree of subjectivity in the judgment as to
whether an allocation is seen as socially just or ethical. There are different
principles by which we can view distributive justice and which therefore affect the
prism of subjectivity through which we see certain problems. For example, we might say
that distributive justice at a certain institution or in a certain medical education
system operates according to the principle that resources must be divided equally
amongst learners. Another system may say that resources should be distributed according
to the needs of learners or even of patients. No ethical system or model is inherently
right or wrong, they depend on the context in which the educator is working.
The [NiFe]‐hydrogenase accessory chaperones HypC and HybG of Escherichia coli are iron‐ and carbon dioxide‐binding proteins
Authors: Soboh Basem , Stripp Sven T. , Bielak Claudia , Lindenstrauß Ute , Braussemann Mario , Javaid Mahwish , Hallensleben Magnus , Granich Claudia , Herzberg Martin , Heberle Joachim , Sawers R. Gary
Published: July 2013

HybG
and
HybG
bind by comigration in sds page (View interaction)
Structure of an atypical periplasmic adaptor from a multidrug efflux pump of the spirochete Borrelia burgdorferi
Authors: Greene Nicholas P. , Hinchliffe Philip , Crow Allister , Ababou Abdessamad , Hughes Colin , Koronakis Vassilis
Published: July 2013

Periplasmic adaptor proteins are essential components of bacterial tripartite multidrug efflux pumps. Here we report the 2.35 Å resolution crystal structure of the BesA adaptor from the spirochete Borrelia burgdorferi solved using selenomethionine derivatized protein. BesA shows the archetypal linear, flexible, multi‐domain architecture evident among proteobacteria and retains the lipoyl, β‐barrel and membrane‐proximal domains that interact with the periplasmic domains of the inner membrane transporter. However, it lacks the α‐hairpin domain shown to establish extensive coiled‐coil interactions with the periplasmic entrance helices of the outer membrane‐anchored TolC exit duct. This has implications for the modelling of assembled tripartite efflux pumps.
Co‐evolution of HAD phosphatase and hotdog‐fold thioesterase domain function in the menaquinone‐pathway fusion proteins BF1314 and PG1653
Authors: Wang Min , Song Feng , Wu Rui , Allen Karen N. , Mariano Patrick S. , Dunaway-Mariano Debra
Published: July 2013

The function of a Bacteroidetes menaquinone biosynthetic pathway fusion protein comprised of an N‐terminal haloacid dehalogenase (HAD) family domain and a C‐terminal hotdog‐fold family domain is described. Whereas the thioesterase domain efficiently catalyzes 1,4‐dihydroxynapthoyl‐CoA hydrolysis, an intermediate step in the menaquinone pathway, the HAD domain is devoid of catalytic activity. In some Bacteroidetes a homologous, catalytically active 1,4‐dihydroxynapthoyl‐CoA thioesterase replaces the fusion protein. Following the gene fusion event, sequence divergence resulted in a HAD domain that functions solely as the oligomerization domain of an otherwise inactive thioesterase domain.