bluuebunny/crossref_metadata_2025 huggingface dataset:
Performance modeling of microsecond scale biological molecular dynamics simulations on heterogeneous architectures
Authors: Agarwal Pratul K. , Hampton Scott , Poznanovic Jeffrey , Ramanthan Arvind , Alam Sadaf R. , Crozier Paul S.
Published: October 2012

Performance improvements in biomolecular simulations based on molecular dynamics (MD) codes are widely desired. Unfortunately, the factors, which allowed past performance improvements, particularly the microprocessor clock frequencies, are no longer increasing. Hence, novel software and hardware solutions are being explored for accelerating performance of widely used MD codes. In this paper, we describe our efforts on porting, optimizing and tuning of Large‐scale Atomic/Molecular Massively Parallel Simulator, a popular MD framework, on heterogeneous architectures: multi‐core processors with graphical processing unit (GPU) accelerators. Our implementation is based on accelerating the most computationally expensive non‐bonded interaction terms on the GPUs and overlapping the computation on the CPU and GPUs. This functionality is built on top of message passing interface that allows multi‐level parallelism to be extracted even at the workstation level with the multi‐core CPUs and allows extension of the implementation on GPU‐enabled clusters. We hypothesize that the optimal benefit of heterogeneous architectures for applications will come by utilizing all possible resources (for example, CPU‐cores and GPU devices on GPU‐enabled clusters). Benchmarks for a range of biomolecular system sizes are provided, and an analysis is performed on four generations of NVIDIA's GPU devices. On GPU‐enabled Linux clusters, by overlapping and pipelining computation and communication, we observe up to 10‐folds application acceleration in multi‐core and multi‐GPU environments illustrating significant performance improvements. Detailed analysis of the implementation is presented that allows identification of bottlenecks in algorithm, indicating that code optimization and improvements on GPUs could allow microsecond scale simulation throughput on workstations and inexpensive GPU clusters, putting widely desired biologically relevant simulation time‐scales within reach of a large user community. In order to systematically optimize simulation throughput and to enable performance prediction, we have developed a parameterized performance model that will allow developers and users to explore the performance potential of future heterogeneous systems for biological simulations. Copyright © 2012 John Wiley & Sons, Ltd.
Detection and characterization of urinary metabolites of boldione by LC‐MS/MS. Part II: Conjugates with cysteine and N‐acetylcysteine
Authors: Pozo Oscar J. , Gómez Cristina , Marcos Josep , Segura Jordi , Ventura Rosa
Published: October 2012

The occurrence of boldione metabolites conjugated with cysteine and N‐acetylcysteine in human urine was evaluated. Methods based on precursor ion scan of the protonated aminoacid (m/z 122 and m/z 164 for cysteine and N‐acetylcysteine respectively) and neutral losses of the aminoacids (121 Da and 163 Da for cysteine and N‐acetylcysteine respectively) were applied for the open detection of conjugates. Results for urine samples collected before and after boldione administration were compared. Using this approach, 24 metabolites (eleven conjugates with cysteine and thirteen conjugated with N‐acetylcysteine) were detected. The metabolites were characterized by mass spectrometry and their potential structures were proposed based on this information. The structures of nine of these metabolites were confirmed by the synthesis of the conjugates. According to these results, a metabolic pathway for boldione involving this type of conjugation was presented. Up to our knowledge this is the first time that cysteine conjugates are presented for exogenous anabolic androgenic steroids and the first report of N‐acetylcysteine conjugates for steroids. Copyright © 2012 John Wiley & Sons, Ltd.
Generation and characterization of a tamoxifen inducible Msx1CreERT2 knock‐in allele
Authors: Lallemand Yvan , Moreau Julie , Cloment Cécile Saint , Vives Francina Langa , Robert Benoît
Published: October 2012

Msx1, a member of the Msx gene family, encodes a homeodomain transcription factor and plays critical roles during mouse development in numerous organs. By homologous recombination, we generated a new Msx1 allele (Msx1CreERT2) in which the CreERT2 fusion protein is produced in place of the endogenous Msx1 protein. Using different reporter mouse strains and appropriate tamoxifen treatments, we show that, in mice bearing the Msx1CrERT2 allele, CreERT2 is capable to induce loxP genomic recombination specifically in Msx1‐expressing cells and that this can be obtained during embryonic development as well as after birth. These results show that this new mouse line can be used for lineage tracing of Msx1‐expressing cells and their descendants and, combined with Cre‐inducible Msx null alleles, for the analysis of Msx1 and/or Msx2 functions in the Msx1‐expressing organs, in a time‐dependant manner. genesis 51:110–119, 2013. © 2012 Wiley Periodicals, Inc.
Copper‐Catalyzed Cascade Synthesis of 1H‐Indolo[1,2‐c]quinazoline Derivatives
Authors: Zhang Hao , Jin Yibao , Liu Hongxia , Jiang Yuyang , Fu Hua
Published: October 2012

A simple, efficient and practical approach to 1H‐indolo[1,2‐c]quinazoline derivatives has been developed that uses inexpensive and readily‐available catalyst and substrates. The method should provide a new strategy for N‐fused heterocycles and will show wide application in organic chemistry and medicinal chemistry.
Formation of Intermediate Layers for Immobilization of Biomacromolecules by Self‐Assembling and Reduction of Phenyldiazonium Salts. A Comparative Study
Authors: Kowalczyk Agata , Fau Michal , Nowicka Anna M. , Stojek Zbigniew
Published: October 2012

Two types of biomolecules were tested in the comparison of usefulness of two ways of formation of the intermediate layers at electrodes: a 20‐nucleotide DNA sequence and glucose oxidase. Chronocoulometric, amperometric, electrochemical impedance and PM‐IRRAS experiments proved that the layers obtained by electroreduction of diazonium salts are much more stable and more efficient in the accumulation of biomolecules compared to layers obtained by self‐assembling of appropriate thiols.
Surface‐Imprinting Sensor Based on Carbon Nanotubes/Graphene Composite for Determination of Bovine Serum Albumin
Authors: Chen Hong‐Jun , Zhang Zhao‐Hui , Xie Duo , Cai Rong , Chen Xing , Liu Yu‐Nan , Yao Shou‐Zhuo
Published: October 2012

A novel molecularly imprinted sensor was firstly prepared based on a carbon nanotubes/graphene composite modified carbon electrode (MIPs/CNT/GP/CE) for the selective determination of bovine serum albumin. The molecularly imprinted sensor was tested by differential pulse voltammetry (DPV) to investigate the relationship between the response current and bovine serum albumin concentration. The results showed that a wide linear range (1.0×10−4 to 1.0×10−10 g mL−1) for the detection of bovine serum albumin with a low detection limit of 6.2×10−11 g mL−1 for S/N=3 was obtained. The novel imprinted sensor exhibited high selectivity, sensitivity, and reproducibility, which provided an applicable way for sensor development.
In vitro MS‐based proteomic analysis and absolute quantification of neuronal‐glial injury biomarkers in cell culture system
Authors: Guingab‐Cagmat Joy D. , Newsom Kimberly , Vakulenko Anatoliy , Cagmat Emilio B. , Kobeissy Firas H. , Zoltewicz Susie , Wang Kevin K. , Anagli John
Published: October 2012

MS‐based proteomics has been the method of choice for biomarker discovery in the field of traumatic brain injury (TBI). Due to its high sensitivity and specificity, MS is now being explored for biomarker quantitative validation in tissue and biofluids. In this study, we demonstrate the use of MS in both qualitative protein identification and targeted detection of acute TBI biomarkers released from degenerating cultured rat cortical mixed neuronal cells, mimicking intracellular fluid in the central nervous system after TBI. Calpain activation was induced by cell treatment with maitotoxin (MTX), a known calcium channel opener. Separate plates of mixed neuronal‐glial culture were subjected to excitotoxin N‐methyl‐D‐aspartate (NMDA) and apoptotic inducer staurosporine. Acute TBI biomarkers, GFAP and UCH‐L1, were first detected and assessed in the culture media by Western blot. The cell‐conditioned media were then trypsinized and subjected to bottom up proteomic analysis. GFAP was readily detected by data‐dependent scanning but not UCH‐L1. As a proof‐of‐principle study, rat glia‐enriched cell cultures treated with MTX were used to investigate the time‐dependent release of GFAP breakdown product by Western blot and for isotope dilution MS absolute quantitation method development. Absolute quantitation of the GFAP release was conducted using the three cortical mixed neuronal cell cultures treated with different agents. Other differentially expressed proteins identified in the glial‐enriched and cortical mixed neuronal cell culture models were further analyzed by bioinformatic tools. In summary, this study demonstrates the use of MS in both protein identification and targeted quantitation of acute TBI biomarkers and is the preliminary step toward development of TBI biomarker validation by targeted MS.
CE‐MS for the analysis of intact proteins 2010–2012
Authors: Haselberg Rob , de Jong Gerhardus J. , Somsen Govert W.
Published: October 2012

Since its introduction in 1987, CE‐MS has become an increasingly important technique for the analysis of biomolecules. Since our previous update on CE‐MS methods within the field of intact protein analysis (Electrophoresis 2011, 32, 66–82), a variety of interesting methodological improvements and applications have been reported in literature. Therefore, this article presents an overview of the development and application of CE‐MS for intact protein analysis as published between June 2010 and June 2012. The article is divided in sections that treat CE coupled to MS through ESI, MALDI, and ICP ionization, respectively. In the section about CE‐ESI‐MS, technological developments with respect to CE‐MS interfacing, prevention of protein adsorption, and chip‐based CE‐MS are treated in more detail. Novel interfacing strategies and the development of improved capillary coating strategies appeared to be the major developments. Furthermore, in all sections, the applicability of CE‐MS for intact protein analysis is demonstrated by representative examples, including important developments in the fields of biopharmaceutical characterization and the analysis of proteins in biological samples. Finally, some general conclusions and future perspectives are given.
Height, age at menarche and risk of hormone receptor‐positive and ‐negative breast cancer: A cohort study
Authors: Ritte Rebecca , Lukanova Annekatrin , Tjønneland Anne , Olsen Anja , Overvad Kim , Mesrine Sylvie , Fagherazzi Guy , Dossus Laure , Teucher Birgit , Steindorf Karen , Boeing Heiner , Aleksandrova Krasimira , Trichopoulou Antonia , Lagiou Pagona , Trichopoulos Dimitrios , Palli Domenico , Grioni Sara , Mattiello Amalia , Tumino Rosario , Sacerdote Carlotta , Quirós José Ramón , Buckland Genevieve , Molina‐Montes Esther , Chirlaque María‐Dolores , Ardanaz Eva , Amiano Pilar , Bueno‐de‐Mesquita Bas , van Duijnhoven Franzel , van Gils Carla H , Peeters Petra HM , Wareham Nick , Khaw Kay‐Tee , Key Timothy J , Travis Ruth C. , Krum‐Hansen Sanda , Gram Inger Torhild , Lund Eiliv , Sund Malin , Andersson Anne , Romieu Isabelle , Rinaldi Sabina , McCormack Valerie , Riboli Elio , Kaaks Rudolf
Published: October 2012

Associations of breast cancer overall with indicators of exposures during puberty are reasonably well characterized; however, uncertainty remains regarding the associations of height, leg length, sitting height and menarcheal age with hormone receptor‐defined malignancies. Within the European Prospective Investigation into Cancer and Nutrition cohort, Cox proportional hazards models were used to describe the relationships of adult height, leg length and sitting height and age at menarche with risk of estrogen and progesterone receptor negative (ER‐PR‐) (n = 990) and ER+PR+ (n = 3,524) breast tumors. Height as a single risk factor was compared to a model combining leg length and sitting height. The possible interactions of height, leg length and sitting height with menarche were also analyzed. Risk of both ER‐PR‐ and ER+PR+ malignancies was positively associated with standing height, leg length and sitting height and inversely associated with increasing age at menarche. For ER+PR+ disease, sitting height (hazard ratios: 1.14[95% confidence interval: 1.08–1.20]) had a stronger risk association than leg length (1.05[1.00–1.11]). In comparison, for ER‐PR‐ disease, no distinct differences were observed between leg length and sitting height. Women who were tall and had an early menarche (≤13 years) showed an almost twofold increase in risk of ER+PR+ tumors but no such increase in risk was observed for ER‐PR‐ disease. Indicators of exposures during rapid growth periods were associated with risks of both HR‐defined breast cancers. Exposures during childhood promoting faster development may establish risk associations for both HR‐positive and −negative malignancies. The stronger associations of the components of height with ER+PR+ tumors among older women suggest possible hormonal links that could be specific for postmenopausal women.
International Faculty in American Universities: Experiences of Academic Life, Productivity, and Career Mobility
Authors: Kim Dongbin , Twombly Susan , Wolf‐Wendel Lisa
Published: October 2012

The increasing presence of international faculty members is validated using multiple data sources, and their professional experience is examined in terms of the perception of academic life, productivity, and career mobility.
Development of D‐lysine‐assisted 1‐ethyl‐3‐(3‐dimethylaminopropyl)‐carbodiimide/N‐hydroxysuccinimide‐initiated cross linking of collagen matrix for design of scaffold
Authors: Krishnamoorthy Ganesan , Sehgal Praveen Kumar , Mandal Asit Baran , Sadulla Sayeed
Published: October 2012

This work discusses the preparation and characterization of collagen scaffold with presence of D‐Lysine (Coll‐D‐Lys)‐assisted 1‐ethyl‐3‐(3‐dimethylaminopropyl)‐carbodiimide (EDC)/N‐hydroxysuccinimide (NHS)‐initiated cross linking. The mechanical strength, thermal and structural stability, resistance to biodegradation and cell viability of this scaffold was investigated. The results of the Coll‐D‐Lys‐EDC/NHS scaffold also indicate an increase in the tensile strength (TS), percentage of elongation (% E), denaturation temperature (Td), and decrease the decomposition rate. Scanning electron microscopic (SEM) and atomic force microscopic (AFM) analyses revealed a well ordered with properly oriented and well‐aligned structure of scaffold. The D‐Lys stabilizes the scaffold against degradation by collagenase than L‐Lys. The cell assay showed more than 98 ± 2% fibroblast viability (NIH 3T3) after 72 h of culture Coll‐D‐Lys‐scaffold when compared with native Coll and Coll‐L‐Lys‐scaffold. The proteolytic machinery is not well equipped to deal with Coll‐D‐Lys‐scaffold than Coll‐L‐Lys‐scaffold. Incorporating D‐Lys in scaffold design has the potential to improve existing collagen stability and create new topologies inaccessible to homochiral molecules. This method may assist in the functionalization of the scaffold for regenerative applications. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013.
Differential in vitro and cellular effects of iron chelators for hypoxia inducible factor hydroxylases
Authors: Cho Eun A. , Song Hyun Kyung , Lee Sang‐Hyeup , Chung Bong Hyun , Lim Heon Man , Lee Myung Kyu
Published: October 2012

Hypoxia inducible factor 1α (HIF‐1α), an essential transcriptional factor, is negatively regulated by two different types of oxygen and Fe2+‐dependent HIF hydroxylases, proline hydroxylase (PHD) and factor inhibiting HIF (FIH), under normoxia. Iron chelators have therefore been used for inducing HIF‐1α expression by inhibiting the hydroxylases. In this study, the iron chelators displayed differential effects for PHD and FIH in cells depending on their iron specificity and membrane permeability rather than their in vitro potencies. The membrane permeability of the strict Fe2+‐chelator potentially inhibited both hydroxylases, whereas the membrane impermeable one showed no inhibitory effect in cells. In contrast, the depletion of the extracellular Fe3+ ion was mainly correlated to PHD inhibition, and the membrane permeable one elicited low efficacy for both enzymes in cells. The 3′‐hydroxyl group of quercetin, a natural flavonoid, was critical for inhibition of intracellular hydroxylases. Since the 3′‐methylation of quercetin is induced by catechol‐O‐methyl transferase, the enzyme may regulate the intracellular activity of quercetin. These data suggest that the multiple factors of iron‐chelators may be responsible for regulating the intracellular activity HIF hydroxylases. J. Cell. Biochem. 114: 864–873, 2013. © 2012 Wiley Periodicals, Inc.
Craniosynostosis with wormian bone, bowing of the long bones, unilateral short femur, and focal fibula deficiency: A prenatal diagnostic dilemma
Authors: Tonni Gabriele , Lituania Mario , Rosignoli Lucia
Published: October 2012

The prenatal detection in the second trimester of pregnancy of a fetus with craniosynostosis, wide metopic suture, and wormian bone associated with bowing of the long bones, unilateral short femur, and focal fibula deficiency is reported. These ultrasonographic findings when not supported by a diagnostic molecular biology result represent a prenatal dilemma in term of both parent's counseling and management of potential overlapping skeletal diseases. © 2012 Wiley Periodicals, Inc. J Clin Ultrasound 41:448–452, 2013
Synthesis of acyl[35S]sulfonamides: Coupling of high specific activity [35S]methane sulfonamide with acids and acid chlorides
Authors: Wallace Michael , Allentoff Alban J. , Bonacorsi Samuel
Published: October 2012

Direct coupling of high specific activity [35S]methanesulfonamide, generated from [35S]methanesulfonyl chloride and ammonia, with acids and acid chlorides afforded the corresponding [35S]acyl sulfonamides in excellent yields. Examples of high specific activity [35S]acyl sulfonamides were prepared containing functionality that can be further elaborated through carbon–carbon or carbon–nitrogen bond forming reactions.
Rapid gradient‐echo imaging
Authors: Hargreaves Brian
Published: October 2012

Gradient‐echo sequences are widely used in magnetic resonance imaging (MRI) for numerous applications ranging from angiography to perfusion to functional MRI. Compared with spin‐echo techniques, the very short repetition times of gradient‐echo methods enable very rapid 2D and 3D imaging, but also lead to complicated “steady states.” Signal and contrast behavior can be described graphically and mathematically, and depends strongly on the type of spoiling: fully balanced (no spoiling), gradient spoiling, or radiofrequency (RF)‐spoiling. These spoiling options trade off between high signal and pure T1 contrast, while the flip angle also affects image contrast in all cases, both of which can be demonstrated theoretically and in image examples. As with spin‐echo sequences, magnetization preparation can be added to gradient‐echo sequences to alter image contrast. Gradient‐echo sequences are widely used for numerous applications such as 3D perfusion imaging, functional MRI, cardiac imaging, and MR angiography. J. Magn. Reson. Imaging 2012; 36:1300–1313. © 2012 Wiley Periodicals, Inc.
Differentiation of malignant and benign breast lesions using magnetization transfer imaging and dynamic contrast‐enhanced MRI
Authors: Heller Samantha L. , Moy Linda , Lavianlivi Sherlin , Moccaldi Melanie , Kim Sungheon
Published: October 2012

Purpose:

To evaluate feasibility of using magnetization transfer ratio (MTR) in conjunction with dynamic contrast‐enhanced MRI (DCE‐MRI) for differentiation of benign and malignant breast lesions at 3 Tesla.

Materials and Methods:

This prospective study was IRB and HIPAA compliant. DCE‐MRI scans followed by MT imaging were performed on 41 patients. Regions of interest (ROIs) were drawn on co‐registered MTR and DCE postcontrast images for breast structures, including benign lesions (BL) and malignant lesions (ML). Initial enhancement ratio (IER) and delayed enhancement ratio (DER) were calculated, as were normalized MTR, DER, and IER (NMTR, NDER, NIER) values. Diagnostic accuracy analysis was performed.

Results:

Mean MTR in ML was lower than in BL (P < 0.05); mean DER and mean IER in ML were significantly higher than in BL (P < 0.01, P < 0.001). NMTR, NDER, and NIER were significantly lower in ML versus BL (P < 0.007, P < 0.001, P < 0.001). IER had highest diagnostic accuracy (77.6%), sensitivity (86.2%), and area under the ROC curve (.879). MTR specificity was 100%. Logistic regression modeling with NMTR and NIER yielded best results for BL versus ML (sensitivity 93.1%, specificity 80%, AUC 0.884, accuracy 83.7%).

Conclusion:

Isolated quantitative DCE analysis may increase specificity of breast MR for differentiating BL and ML. DCE‐MRI with NMTR may produce a robust means of evaluating breast lesions. J. Magn. Reson. Imaging 2013;37:138–145. © 2012 Wiley Periodicals, Inc.
Arterial enhancing‐only nodules less than 2 cm in diameter in patients with liver cirrhosis: Predictors of hepatocellular carcinoma diagnosis on gadobenate dimeglumine‐enhanced mr imaging
Authors: Quaia Emilio , Pizzolato Riccardo , De Paoli Luca , Angileri Roberta , Ukmar Maja , Assunta Cova Maria
Published: October 2012

Purpose:

To assess whether gadobenate dimeglumine (Gd‐BOPTA)‐enhanced MR imaging could predict hepatocellular carcinoma (HCC) diagnosis in small arterial enhancing‐only nodules detected by contrast‐enhanced computed tomography (CT) in patients with liver cirrhosis.

Materials and Methods:

We prospectively recruited 125 cirrhotic patients (67 males, and 58 females; age: 68 ± 12.36 years) with 151 small (<2 cm in diameter) arterial enhancing‐only nodules identified by contrast‐enhanced CT. All patients were scanned by MR imaging before and after Gd‐BOPTA injection during the hepatic arterial phase (HAP), portal venous phase (PVP), equilibrium phase (EP), and hepatobiliary phase (HP). Nodule characterization was based on reference imaging criteria (n = 29 nodules), follow‐up (n = 105), or histology (n = 17). Two radiologists (5 and 10 years experience) analyzed the MR images, and logistic regression was conducted to assess how well MR imaging findings could predict HCC diagnosis.

Results:

Final diagnoses included 115 benign nodules and 36 HCCs. Nodule T2 hyperintensity, T1 hypointensity, PVP‐EP hypointensity, and HP hypointensity were the best predictors of HCC on univariate analysis. Nodule T2 hyperintensity, T1 hypointensity, and HP hypointensity, were independent predictors of HCC on multivariate analysis.

Conclusion:

Gd‐BOPTA‐enhanced MR imaging provides imaging findings which may predict a diagnosis of HCC in small arterial enhancing‐only nodules in cirrhotic patients. J. Magn. Reson. Imaging 2013;37:892–902. © 2012 Wiley Periodicals, Inc.
Automated unsupervised multi‐parametric classification of adipose tissue depots in skeletal muscle
Authors: Valentinitsch Alexander , C. Karampinos Dimitrios , Alizai Hamza , Subburaj Karupppasamy , Kumar Deepak , M. Link Thomas , Majumdar Sharmila
Published: October 2012

Purpose:

To introduce and validate an automated unsupervised multi‐parametric method for segmentation of the subcutaneous fat and muscle regions to determine subcutaneous adipose tissue (SAT) and intermuscular adipose tissue (IMAT) areas based on data from a quantitative chemical shift‐based water‐fat separation approach.

Materials and Methods:

Unsupervised standard k‐means clustering was used to define sets of similar features (k = 2) within the whole multi‐modal image after the water‐fat separation. The automated image processing chain was composed of three primary stages: tissue, muscle, and bone region segmentation. The algorithm was applied on calf and thigh datasets to compute SAT and IMAT areas and was compared with a manual segmentation.

Results:

The IMAT area using the automatic segmentation had excellent agreement with the IMAT area using the manual segmentation for all the cases in the thigh (R2: 0.96) and for cases with up to moderate IMAT area in the calf (R2: 0.92). The group with the highest grade of muscle fat infiltration in the calf had the highest error in the inner SAT contour calculation.

Conclusion:

The proposed multi‐parametric segmentation approach combined with quantitative water‐fat imaging provides an accurate and reliable method for an automated calculation of the SAT and IMAT areas reducing considerably the total postprocessing time. J. Magn. Reson. Imaging 2013;37:917–927. © 2012 Wiley Periodicals, Inc.
Altered loading in the injured knee after ACL rupture
Authors: Gardinier Emily S. , Manal Kurt , Buchanan Thomas S. , Snyder‐Mackler Lynn
Published: October 2012

Articular loading is an important factor in the joint degenerative process for individuals with anterior cruciate ligament (ACL) rupture. Evaluation of loading for a population that exhibits neuromuscular compensation for injury requires an approach which can incorporate individual muscle activation strategies in its estimation of muscle forces. The purpose of this study was to evaluate knee joint contact forces for patients with ACL deficiency using an EMG‐driven modeling approach to estimate muscle forces. Thirty athletes with acute, unilateral ACL rupture underwent gait analysis after resolving range of motion, effusion, pain, and obvious gait impairments. Electromyography was recorded bilaterally from 14 lower extremity muscles and input to a musculoskeletal model for estimation of muscle forces and joint contact forces. Gait mechanics were consistent with previous reports for individuals with ACL‐deficiency. Our major finding was that joint loading was altered in the injured limb after acute ACL injury; patients walked with decreased contact force on their injured knee compared to their uninjured knee. Both medial and lateral compartment forces were reduced without a significant change in the distribution of tibiofemoral load between compartments. This is the first study to estimate medial and lateral compartment contact forces in patients with acute ACL rupture using an approach which is sensitive to individual muscle activation patterns. Further work is needed to determine whether this early decreased loading of the injured limb is involved in the development of osteoarthritis in these patients. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31: 458–464, 2013
The rigid relation principle, a new weak choice principle
Authors: Hamkins Joel David , Palumbo Justin
Published: October 2012

The rigid relation principle, introduced in this article, asserts that every set admits a rigid binary relation. This follows from the axiom of choice, because well‐orders are rigid, but we prove that it is neither equivalent to the axiom of choice nor provable in Zermelo‐Fraenkel set theory without the axiom of choice. Thus, it is a new weak choice principle. Nevertheless, the restriction of the principle to sets of reals (among other general instances) is provable without the axiom of choice.
Compressible Magnetorheological Fluids Based on Composite Polyurethane Microspheres
Authors: Pramudya Irawan , Sutrisno Joko , Fuchs Alan , Kavlicoglu Barkan , Sahin Huseyin , Gordaninejad Faramarz
Published: October 2012

A novel CMRF is synthesized from modified silicone oil, containing composite polyurethane microsphere additives, and surface‐coated iron particles. The CMRF is designed to act as a liquid spring with controllable damping properties in a damper system. The fluid compressibility is characterized by force/displacement measurements. The addition of composite polyurethane‐microspheres increases the strength and compressibility of the fluid. It also decreases the concentration of iron particles needed in order to achieve the same yield stress as commercially available MRF. Surface coating surface of the iron particles with poly(2,3,4,5,6‐pentafluorostyrene) via RAFT provides dispersion stability.

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Structure/Property Relationships of Partially Crosslinked Poly(butylene succinate)
Authors: Ma Piming , Ma Zhe , Dong Weifu , Zhang Yong , Lemstra Pieter Jan
Published: October 2012

PBS is partially crosslinked by using DCP as an initiator. A low gel fraction (<30 wt%) and low crosslink density of the partially crosslinked PBS are obtained at a DCP content of <0.5 wt%. Consequently, the partially crosslinked PBS retains both its processability and its crystallinity. The overall crystallization rate of the PBS is enhanced by partial crosslinking as evidenced by a considerable increase in crystallization temperature (Tc). Meanwhile, the mechanical properties of PBS are significantly improved by the partial crosslinking. The structure/property relationships of the partially crosslinked PBS are explored.

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Flexural‐Torsional Photomechanical Responses in Azobenzene‐Containing Crosslinked Polyimides
Authors: Wang David H. , Lee Kyung Min , Koerner Hilmar , Yu Zhenning , Vaia Richard A. , White Timothy J. , Tan Loon‐Seng
Published: October 2012

The influence of a variety of factors on the photomechanical output of azo‐CP2‐xx systems is studied, primarily focusing on a sample with a higher crosslink density (30 mol%) and two new, structurally related crosslinked polyimides with modified backbone flexibility/rigidity. This work elucidates the strong coupling between geometrical considerations (reciprocal aspect ratio of cantilever) and the visualized mechanical response (e.g., flexural‐torsional response of a cantilever).

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Living copolymerization of ethylene/1‐octene with fluorinated FI‐Ti catalyst
Authors: Liu Weifeng , Zhang Kailun , Fan Hong , Wang Wen‐Jun , Li Bo‐Geng , Zhu Shiping
Published: October 2012

Living copolymerization of ethylene and 1‐octene was carried out at room temperature using the fluorinated FI‐Ti catalyst system, bis[N‐(3‐methylsalicylidene)‐2,3,4,5,6‐pentafluoroanilinato] TiCl2/dried methylaluminoxane, with various 1‐octene concentrations. The comonomer incorporation up to 32.7 mol % was achieved at the 1‐octene feeding ratio of 0.953. The living feature still retained at such a high comonomer level. The copolymer composition drifting was minor in this living copolymerization system despite of a batch process. It was found that the polymerization heterogeneity had a severe effect on the copolymerization kinetics, with the apparent reactivity ratios in slurry significantly different from those in solution. The reactivity ratios were nearly independent of polymerization temperature in the range of 0–35 °C. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013
MALDI MS imaging as a tool for biomarker discovery: Methodological challenges in a clinical setting
Authors: Minerva Laurens , Ceulemans An , Baggerman Geert , Arckens Lutgarde
Published: October 2012

MALDI MS imaging (MSI) is an analytical tool capable of providing spatial distribution and relative abundance of biomolecules directly in tissue. After 15 years of intense efforts to improve the acquisition and quality of molecular images, MSI has matured into an asset of the proteomic toolbox. The power of MSI lies in the ability to differentiate tissue regions that are not histologically distinct but are characterized by different MS profiles. Recently, MSI has been gaining momentum in biomedical research and has found applications in disease diagnosis and prognosis, biomarker discovery, and drug therapy. Although the technology holds great promise, MSI is still faced with a set of methodological challenges presented by the clinical setting. There is a growing awareness regarding this topic and efforts are being taken to develop clear and practical standards to overcome these challenges. This review presents an overview of MALDI MSI as a biomarker discovery tool and recent methodological progress in the field.
DFT investigations of the piezoresistive effect of carbon nanotubes for sensor application
Authors: Wagner Christian , Schuster Jörg , Gessner Thomas
Published: October 2012

We investigate the piezoresistive effect of carbon nanotubes (CNTs) within density functional theory (DFT) aiming at application‐relevant CNTs. CNTs are excellent candidates for the usage in nano‐electromechanical sensors (NEMSs) due to their small band gap at zero strain leading to a finite resistivity at room temperature. The application of strain induces a band gap‐opening leading to a tremendous change in the resistivity. DFT with the LDA approximation yields reasonable results for pure carbon systems like CNTs and is applied to calculate the electronic structure of experimentally relevant CNTs. For the transport part, a simple ballistic transport model based on the band gap is used. We compare our DFT results for the band gaps of strained CNTs to results of tight binding (TB) models. By introducing a scaling factor of $\sqrt {2} $, an excellent agreement of the DFT data with TB model, published by Yang and Han [Phys. Rev. Lett. 85, 154 (2000)], is obtained.
Synthesis and luminescent properties of nanocrystalline CaYAlO4:Sm3+ phosphors
Authors: Kim Myung Sub , Yu Jae Su
Published: October 2012

Nanocrystalline CaYAlO4:Sm3+ phosphors were synthesized by a citrate‐based sol–gel method. After annealing at 1000 °C, the closely packed particles with pure tetragonal crystalline structure were observed. The photoluminescence spectra exhibited the emission peaks of 565 nm (4G5/2 → 6H5/2), 600 nm (4G5/2 → 6H7/2), and 650 nm (4G5/2 → 6H9/2) under an excitation wavelength of 409 nm. The optimum concentration of CaYAlO4:Sm3+ phosphors was found to be 2 mol%. The lifetimes were measured to analyze the effect of Sm3+ concentration in CaYAlO4 host lattice. And similar emissions of cathode‐luminescence (CL) spectra were also observed. By increasing the accelerating voltage from 1 to 5 kV, the CL intensity was linearly increased.
Real time egomotion of a nonholonomic vehicle using LIDAR measurements
Authors: Almeida J. , Santos V. M.
Published: October 2012

This paper presents a technique to estimate in real time the egomotion of a vehicle based solely on laser range data. This technique calculates the discrepancy between closely spaced two‐dimensional laser scans due to the vehicle motion using scan matching techniques. The result of the scan alignment is converted into a nonlinear motion measurement and fed into a nonholonomic extended Kalman filter model. This model better approximates the real motion of the vehicle when compared to more simplistic models, thus improving performance and immunity to outliers. The motion estimate is intended to be used for egomotion compensation in a target‐tracking algorithm for situation awareness applications. In this paper, several recent scan matching algorithms were evaluated for their accuracy and computational speed: metric‐based iterative closest point (MbICP), point‐to‐line ICP (PIICP), and polar scan matching. The proposed approach is performed in real time and provides an accurate estimate of the current robot motion. The MbICP algorithm proved to be the most advantageous scan matching algorithm, but it is still comparable to PlICP. The motion estimation algorithm is validated through experimental testing in real world conditions.
Carbon Trading in Malaysia: Review of Policies and Practices
Authors: Amran Azlan , Zainuddin Zainorfarah , Zailani Suhaiza Hanim Mohamad
Published: October 2012

The idea of trading greenhouse gas emissions has become an important tool to tackle the problem of global climate change. Malaysia has started to strive towards a low carbon economy through various policies and initiatives. The main objective of this article is to document the exiting policy developed by the Malaysian government and review some of the current practices pertaining to the Clean Development Mechanism (CDM). The objective of such analysis is to understand what initiatives have been taken by the Malaysian government. Challenges and barriers will be documented for further research to provide a solution. In addition, it will also provide insight into the current CDM practices in Malaysia. It aims to provide a useful reference that could act as a foundation for future study to explore these issues further, particularly in the Malaysian context. It could also be an important reference for practitioners starting a CDM project. Although a review of the existing policy indicates that Malaysia has undertaken several initiatives, much more can be done. More research is now being carried out in order to provide support to the government. Stakeholder engagement is one way of acquiring input for the government to formulate a new policy. The main stakeholders – industry and the bankers – need to be engaged and made to understand to ensure smooth implementation and easy acceptance. Malaysia can also look to the advanced countries if necessary and modify what it learns for the Malaysian context. Copyright © 2012 John Wiley & Sons, Ltd and ERP Environment.
Interactions of Engineered Nanoparticles with Organs Protected by Internal Biological Barriers
Authors: Pietroiusti Antonio , Campagnolo Luisa , Fadeel Bengt
Published: October 2012

Engineered nanomaterials may exert adverse effects on human health which, in turn, may be linked to their propensity to cross biological barriers in the body. Here, available evidence is discussed, based on in vivo studies for interactions of commercially relevant nanoparticles with critical internal barriers. The internal barriers in focus in this review are the blood–brain barrier, protecting the brain, the blood–testis barrier, protecting the male germ line, and the placenta, protecting the developing fetus. The route of exposure (pulmonary, gastro‐intestinal, intravenous, intraperitoneal, dermal), and, hence, the portal of entry of nanoparticles into the body, is of critical importance. Different physico‐chemical properties, not only size, may determine the ability of nanoparticles to breach biological barriers; the situation is further compounded by the formation of a so‐called corona of biomolecules on the surfaces of nanoparticles, the composition of which may vary depending on the route of exposure and the translocation of nanoparticles from one biological compartment to another. The relevance of nanoparticle interactions with internal biological barriers for their impact on the organs protected by these barriers is also discussed.
NASA's Constellation Program: The final word
Authors: Thomas L. Dale , Hanley Jeffrey M. , Rhatigan Jennifer L. , Neubek Deborah
Published: October 2012

NASA's Constellation Program, formulated in 2005 to achieve the objectives of maintaining American presence in low Earth orbit, returning to the Moon for purpose of establishing an outpost, and exploring Mars and beyond in the first half of the 21st century, was cancelled in 2010 [US Congress, NASA Authorization Act, Public Law 11‐267, 2010]. This paper describes the lessons learned developed by the staff of the Constellation Program to advise future programs, as well as program and system engineering managers of similar national efforts. These lessons learned are offered by those who experienced the day‐to‐day challenges of managing an effort planned as a multidecade undertaking. This effort spanned all 10 NASA Centers, multiple large‐scale acquisitions, and required modernizing an infrastructure designed and sized largely for the Apollo program in the 1960s. Moreover, it required leading a workforce generationally removed from the previous human spacecraft launch and entry development challenges. Key lessons learned from the Constellation Program are addressed and cover program elements in which systems engineers provide leadership and/or assistance to program management, including program planning, requirements development, system design methodology, management structure, decision‐making, and communications in a national program. ©2012 Wiley Periodicals, Inc. Syst Eng 16:
A framework for capturing the hidden stakeholder system
Authors: Wood John , Sarkani Shahram , Mazzuchi Thomas , Eveleigh Timothy
Published: October 2012

As programs rise in intricacy and scope, the number of stakeholders involved also increases, often driving an exponential growth in program complexity. This complexity is caused by the $n^*(n - 1)/2$ stakeholder relationships which form an underlying system that influences all aspects of the program. Understanding, managing, and leveraging this stakeholder system will greatly increase a program's probability of success. This paper provides a framework for capturing this stakeholder system in a series of architectural views. These architectural products document the program's stakeholder concerns and also illustrate how those stakeholders interrelate over the system's lifecycle. The ultimate objective for the framework and use of the resulting products is to allow for right‐sized stakeholder involvement, promote effective use of resources, and increase the probability of overall program success with the assurance of lasting stakeholder commitment. Additionally, this unique insertion of Stakeholder Analysis and Social Network Analysis into an Architecture Framework fulfills an original intent of Architecture Framework, capturing the entire sociotechnical enterprise system. ©2012 Wiley Periodicals, Inc. Syst Eng 16
HRM, Organizational Capacity for Change, and Performance: A Global Perspective
Authors: Shipton Helen , Budhwar Pawan S. , Crawshaw Jonathan
Published: October 2012

This special issue brings together a variety of articles, each one enriching understanding about whether and how human resource management (HRM) influences organizational performance (however defined) against a backdrop of complex change. We present a preliminary framework that enables us to integrate the diverse themes explored in the special issue, proposing a mediating role for organizational change capacity (OCC). OCC represents a particular subset within the resource‐based literature labeled as “dynamic capabilities.” Although not well researched, there is evidence that OCC is positively associated with firm performance and that this relationship is stronger given conditions of high uncertainty. Our framework reflects on external and internal parameters, which we suggest moderate the relationship between human resource management (HRM), OCC, and organizational performance. Our intention is to provide compelling insight for both practitioners and researchers, especially those whose remit extends beyond national boundaries, with reference to areas of the globe as disparate as Greece, Ireland, Pakistan, Switzerland, and the United Kingdom. © 2012 Wiley Periodicals, Inc.
Talent Management in the Video Game Industry: The Role of Cultural Diversity and Cultural Intelligence
Authors: Scholz Tobias M.
Published: October 2012

Although talent management is a relatively new research stream, it has already witnessed several changes. This research builds on extant work on talent management by focusing on the national culture of team members and finds that national culture, and especially cultural diversity, influences performance. The idea is tested in the video game industry where multicultural development teams create innovative products at a single location. The positive influence of culture varies across the different roles in video game development teams, and the findings confirm the importance of cultural diversity in talent management. These findings provide support for the research model and offer implications for research on cultural diversity and talent management. © 2012 Wiley Periodicals, Inc.
The Role of Job Satisfaction and Self‐Efficacy as Mediating Mechanisms in the Employability and Affective Organizational Commitment Relationship: A Case From a Pakistani University
Authors: Yousaf Amna , Sanders Karin
Published: October 2012

The current article examined the potential role of job satisfaction and self‐efficacy as mediators in the expected relationship between employability and affective organizational commitment (ORC). Data were collected from 230 academic staff at a public university in Pakistan. Findings supported our hypotheses as (1) employability was positively related to ORC, (2) job satisfaction, and (3) self‐efficacy mediated the employability–ORC relationship. Moreover, the results indicated that job satisfaction had more power compared to self‐efficacy as a mediator in the employability–ORC relationship. Implications of the study are discussed in the end. © 2012 Wiley Periodicals, Inc.
Use of polystyrene nanoparticles synthesized by differential microemulsion polymerization for property improvement of (vinyl acetate)‐ethylene copolymer
Authors: Chuayjuljit Saowaroj , Piyawong Nutnicha
Published: October 2012

The nanolatex of polystyrene (PS) synthesized by differential microemulsion polymerization was blended with (vinyl acetate)‐ethylene (VAE) copolymer emulsion at VAE/PS dry weight ratios of 90/10, 80/20, 70/30, and 60/40. This technique provided a well dispersion of PS nanoparticles in the blends without any phase separation or flocculation. The blended emulsions were cast into thin sheet for further characterizations. It was found that the tensile strength, Young's modulus, dynamic mechanical properties, and thermal stability at 50% degradation of VAE were increased by the addition of an appropriate amount (20, 30, 40, and 40 wt%, respectively) of the PS nanoparticles, whereas the elongation at break deteriorated. J. VINYL ADDIT. TECHNOL., 2012. © 2012 Society of Plastics Engineers
X‐ray‐induced alteration of specimens as crucial obstacle in XRF spectrometry of fluorine in rocks and soils
Authors: Pleßow Alexander
Published: October 2012

Occasionally suggested yet rarely performed X‐ray fluorescence (XRF) spectrometry of fluorine seems to fail systematically in yielding reliable quantitative results for rocks and soils. Repeated analyses reveal continuously drifting fluorescence intensities for fluorine, boron and chlorine. Typically, an increase, but in few cases also a decrease, over X‐ray exposure time is observed. For instance, fluorine concentrations in a soil standard appear to increase steadily from below the detection limit in the first run to nearly 850 mg/kg F more than 10 h later in the last. In contrast, cryolite is characterised by drastically decreasing intensities for fluorine. Although fluorescence intensities may be affected by preparation methods, specimen surface conditions and dynamic contamination, it is shown that none of these influencing factors is responsible for the observed trends. In fact, there is evidence that X‐radiation impact mobilises fluorine, boron and chlorine. Diffusion of radiolysis products towards the specimen's surface as well as the kinetics of adsorption and desorption or chemical reactions are believed to control the analyte concentration in the analysed layer decisively. Furthermore, during analysis, the latter is altered by considerable losses of binder or flux – if applicable – thus enhancing XRF intensities of boron and fluorine because of reduced absorption. In any case, signal stability appears to be limited by insufficient sample and specimen stability. It is concluded that for many soil and rock samples, XRF spectrometry is inappropriate to quantify fluorine, although the crucial obstacle is neither the analytical method nor the spectrometer sensu strictu. Copyright © 2012 John Wiley & Sons, Ltd.