bluuebunny/crossref_metadata_2025 huggingface dataset:
Detection of EPO doping and blood doping: the haematological module of the Athlete Biological Passport
Authors: Schumacher Yorck Olaf , Saugy Martial , Pottgiesser Torben , Robinson Neil
Published: February 2012

The increase of the body's capacity to transport oxygen is a prime target for doping athletes in all endurance sports. For this pupose, blood transfusions or erythropoiesis stimulating agents (ESA), such as erythropoietin, NESP, and CERA are used. As direct detection of such manipulations is difficult, biomarkers that are connected to the haematopoietic system (haemoglobin concentration, reticulocytes) are monitored over time (Athlete Biological Passport (ABP)) and analyzed using mathematical models to identify patterns suspicious of doping. With this information, athletes can either be sanctioned directly based on their profile or targeted with conventional doping tests.

Key issues for the appropriate use of the ABP are correct targeting and use of all available information (e.g. whereabouts, cross sectional population data) in a forensic manner.

Future developments of the passport include the correction of all concentration‐based variables for shifts in plasma volume, which might considerably increase sensitivity. New passport markers from the genomic, proteomic, and metabolomic level might add further information, but need to be validated before integration into the passport procedure.

A first assessment of blood data of federations that have implemented the passport show encouraging signs of a decreased blood‐doping prevalence in their athletes, which adds scientific credibility to this innovative concept in the fight against ESA‐ and blood doping. Copyright © 2012 John Wiley & Sons, Ltd.
Development and validation of an HPLC‐UV method for simultaneous determination of zidovudine, lamivudine, and nevirapine in human plasma and its application to pharmacokinetic study in human volunteers
Authors: Nandi Utpal , Das Ayan , Roy Bikash , Choudhury Hira , Gorain Bapi , Pal Tapan Kumar
Published: February 2012

A simple, rapid, and sensitive high performance liquid chromatographic method with UV detection has been developed and validated according to the FDA guidelines for the quantitation of zidovudine (ZDV), lamivudine (LMV), and nevirapine (NVR) in human plasma. The sample was prepared by simple liquid‐liquid extraction. Chromatographic separation was carried out in a Hypersil BDS, C18column (250 mm × 4.6 mm; 5 µm particle size) with simple mobile phase composition of 0.1 M ammonium acetate buffer in 0.5% acetic acid,v/vand methanol (40:60,v/v) at a flow rate of 0.85 ml min‐1where detector was set at 270 nm with a total run time of 10 min which is very short for simultaneous estimation of three analytes in plasma. The method was linear over the concentration range of 50–3000, 50–2000 and 10–3000 ng ml‐1with lower limit of quantifications (LLOQ) of 50, 50, and 10 ng ml‐1for ZDV, LMV, and NVR, respectively. Accuracy and precision values of both within‐run and between‐run obtained from six different sets of three quality control (QC) samples along with the LLOQ analyzed in separate occasions for all the analytes ranged from 94.47–99.71% and 0.298–3.507%, respectively. Extraction recovery of analytes in plasma samples was above 90.16%. In stability tests, all the analytes in human plasma were stable during storage and assay procedure. The developed and validated method was successfully applied to quantitative determination of the three analytes in plasma for pharmacokinetic study in 12 healthy human volunteers. Copyright © 2012 John Wiley & Sons, Ltd.
Coordination Chemistry of α‐ω‐Bis(pyridylimine) Ligands Containing Flexible Linkers with Copper(I)
Authors: Hu Zhenzhong , Schneider Celine M. , Price Christina N. , Pye Whitney M. , Dawe Louise N. , Kerton Francesca M.
Published: February 2012

Copper(I) complexes of a series of six potentially tetradentate bis(pyridylimine) ligands were prepared, where the pyridylimine groups were separated by different linking units [in L1, CH2CH2CH2(SiMe2O)20SiMe2CH2CH2CH2; in L2, CH2CH2CH2SiMe2OSiMe2CH2CH2CH2; in L3, CH2CH2; in L4, CH2(CH2)4CH2; in L5, CH2(CH2)7CH2; in L6, CH2CH2CH2OCH2CH2OCH2CH2OCH2CH2CH2]. The solubilities of L1, L2 and [Cu(L2)](PF6) in supercritical carbon dioxide were determined. The coordination chemistry of L1–L2 with CuI was studied by UV/Vis, multinuclear NMR and IR spectroscopy, MALDI‐TOF and ESI mass spectrometries and elemental analysis. These data suggested that [1+1] complexes had formed. Dicopper complexes of L3–L6 were prepared for comparison, and [Cu2(L5)2](PF6)2 characterized by single‐crystal X‐ray diffraction analysis. Close methylene C–H···π interactions are observed within the structure. PGSE NMR spectroscopy was used to determine the hydrodynamic radii of the species in solution and comparison of these data with computational models for the complexes was made. Freezing point depression measurements afforded molecular weights for solution‐state species in agreement with the formulations proposed via NMR and mass spectrometric data. There is no evidence to support linear metallopolymer formation but data suggest that [2+2] and [1+1] metallomacrocyles were formed, with siloxane linking groups encouraging the formation of [1+1] species. Solid‐state NMR spectroscopic data on [Cu(L1)](PF6) indicate the presence of two different environments for the PF6– anions.
A utility minimization approach for energy‐aware cooperative content distribution with fairness constraints
Authors: Yaacoub Elias , Al-Kanj Lina , Dawy Zaher , Sharafeddine Sanaa , Filali Fethi , Abu‐Dayya Adnan
Published: February 2012

Cooperation between mobile terminals (MTs) with the objective of energy minimization is studied. The purpose is to distribute a content of common interest to collaborating MTs while ensuring a reduced energy consumption. To reach this goal, the content is sent to selected MTs on a long‐range link. Then, it is forwarded to other MTs on short‐range mobile‐to‐mobile links. The problem is formulated as an optimization problem, and the optimal solution is shown to consist of sending the content to a single MT on the long‐range link and of having that MT distribute it on the short‐range links. This leads to an unfair energy consumption for the selected MT. Thus, to ensure fairness in energy consumption, a low complexity utility minimization algorithm is proposed. Using the appropriate utilities, the algorithm can be used to implement the optimal greedy energy minimization solution or to ensure different degrees of fairness in energy consumption. Practical constraints concerning the centralised and distributed implementations of the proposed algorithm are also discussed. Simulation results show that significant energy savings can be achieved with the proposed approach compared with the non‐collaborative case. In addition, a tradeoff between fairness and energy savings is achieved depending on the utility selected. Copyright © 2012 John Wiley & Sons, Ltd.
An unfitted interior penalty discontinuous Galerkin method for incompressible Navier–Stokes two‐phase flow
Authors: Heimann F. , Engwer C. , Ippisch O. , Bastian P.
Published: February 2012

A discontinuous Galerkin method for the solution of the immiscible and incompressible two‐phase flow problem based on the nonsymmetric interior penalty method is presented. Therefore, the incompressible Navier–Stokes equation is solved for a domain decomposed into two subdomains with different values of viscosity and density as well as a singular surface tension force. On the basis of a piecewise linear approximation of the interface, meshes for both phases are cut out of a structured mesh. The discontinuous finite elements are defined on the resulting Cartesian cut‐cell mesh and may therefore approximate the discontinuities of the pressure and the velocity derivatives across the interface with high accuracy. As the mesh resolves the interface, regularization of the density and viscosity jumps across the interface is not required. This preserves the local conservation property of the velocity field even in the vicinity of the interface and constitutes a significant advantage compared with standard methods that require regularization of these discontinuities and cannot represent the jumps and kinks in pressure and velocity. A powerful subtessellation algorithm is incorporated to allow the usage of standard time integrators (such as Crank–Nicholson) on the time‐dependent mesh. The presented discretization is applicable to both the two‐dimensional and three‐dimensional cases. The performance of our approach is demonstrated by application to a two‐dimensional benchmark problem, allowing for a thorough comparison with other numerical methods. Copyright © 2012 John Wiley & Sons, Ltd.
Effect of mine dewatering on peatlands of the James Bay Lowland: the role of bioherms
Authors: Whittington Peter , Price Jonathan
Published: February 2012

The James Bay Lowland host one of the largest wetland complexes in the world in part due to the low permeability of marine sediments that suppress groundwater seepage losses. Dewatering of an open‐pit diamond mine in the area has depressurized the regional bedrock aquifer. Bioherms, fractured limestone outcroppings formed from ancient coral reefs that protrude to the peatland surface, lack this mantle of low‐permeability sediments and provide a direct connection between the peatland (surficial) and the regional (bedrock) aquifers. Well transects and piezometer nests were installed around seven bioherms in the depressurized zone and one in a non‐affected zone (control) to monitor the water table drawdown and change in hydraulic gradients around the bioherms. Water tables in the affected bioherms decreased between 2 and 4 m in the first 4 years of dewatering. The drawdown in the bioherms caused a localized water table drawdown in the peat surrounding the bioherms that extended to approximately 30 m from the edge of the bioherm during a dry period. Under wet conditions, drawdown was similar to that at the control site. Hydraulic gradients in the peat (which typically are very small) increased over the field seasons and in a few locations exceeded 1. These gradients represented significant losses to the local, near bioherm, system as at many of the locations surrounding the bioherms vertical seepage losses ranged between 1 and 4 mm/day, which are similar to the seasonal average evaporative water loss of ~ 3 mm/day. The bioherms are acting as efficient drainage nodes; however, their influence is localized to the peat immediately (~ <30 m) surrounding them. Copyright © 2012 John Wiley & Sons, Ltd.
Ultra‐small‐angle X‐ray scattering–X‐ray photon correlation spectroscopy studies of incipient structural changes in amorphous calcium phosphate‐based dental composites
Authors: Zhang Fan , Allen Andrew J. , Levine Lyle E. , Espinal Laura , Antonucci Joseph M. , Skrtic Drago , O'Donnell Justin N. R. , Ilavsky Jan
Published: February 2012

The local structural changes in amorphous calcium phosphate (ACP)‐based dental composites were studied under isothermal conditions using both static, bulk measurement techniques and a recently developed methodology based on combined ultra‐small angle X‐ray scattering–X‐ray photon correlation spectroscopy (USAXS–XPCS), which permits a dynamic approach. While results from conventional bulk measurements do not show clear signs of structural change, USAXS–XPCS results reveal unambiguous evidence for local structural variations on a similar time scale to that of water loss in the ACP fillers. A thermal‐expansion‐based simulation indicates that thermal behavior alone does not account for the observed dynamics. Together, these results suggest that changes in the water content of ACP affect the composite morphology due to changes in ACP structure that occur without an amorphous‐to‐crystalline conversion. It is also noted that biomedical materials research could benefit greatly from USAXS–XPCS, a dynamic approach. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 2012.
Bone mineral as an electrical energy reservoir
Authors: Nakamura Miho , Hiratai Rumi , Yamashita Kimihiro
Published: February 2012

Mechanical stress in bone induces an electrical potential generated by piezoelectricity arising from displacement of collagen fibrils. Where and for how long the potential is stored in bone; however, are still poorly understood. We investigated the electrical properties of collagen fibrils and apatite minerals and found that bone, when polarized electrically by applying an external voltage, depolarizes by two mechanisms. Plots of thermally stimulated depolarization current show two significant peaks: one at 100°C, attributed to collagen fibrils because decalcified bone exhibits depolarization peak at 100°C, and the other at 500°C, attributed to apatite minerals because calcined bone exhibits depolarization peak at 500°C and has activation energy similar to that for synthesized apatite. The crystallographic c‐axis orientation of calcined bone depends on the direction in which the bone is cut, either transverse or longitudinal, and strongly affects the polarization efficacy. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 2012.
Zwitterionic polycarboxybetaine coating functionalized with REDV peptide to improve selectivity for endothelial cells
Authors: Ji Ying , Wei Yu , Liu Xiangsheng , Wang Jinlei , Ren Kefeng , Ji Jian
Published: February 2012

Surface immobilization of bioactive molecules has been a promising strategy to develop in situ endothelialization for cardiovascular implants. With the aim to construct endothelial cell specific coating with low fouling property, zwitterionic carboxybetaine methacrylate and butyl methacrylate were copolymerized as coating materials, spin‐coated onto substrates, and immobilized with endothelial cell selective peptide Arg‐Glu‐Asp‐Val (REDV) through functionalization of carboxy groups in carboxybetaine by NHS/EDC chemistry. Experimental results proved that carboxybetaine‐REDV coating maintained desirable antifouling ability and fine hemocompatibility. Separate culture and coculture of HUVECs (human umbilical vein endothelial cells) with HUASMCs (human umbilical artery smooth muscle cells) showed that the coating was able to enhance the competitive growth of endothelial cells while limiting the adhesion, proliferation, and migration of smooth muscle cells. The existence of zwitterionic carboxybetaine helps to screen undesirable adsorption of platelets, and its nonspecific resistance to smooth muscle cells contributes to the realization of endothelial cell selectivity. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 2012.
A TDDFT investigation of bay substituted perylenediimides: Absorption and intersystem crossing
Authors: Quartarolo Angelo Domenico , Chiodo Sandro Giuseppe , Russo Nino
Published: February 2012

The conformational structure and electronic spectra properties of a series of bay substituted perylenediimides (PDI) derivatives have been investigated by means of density functional theory (DFT) and time‐dependent DFT. The B3LYP and PBE0 hybrid exchange‐correlation functionals were applied in conjunction with the double‐ζ quality SVP basis set. These compounds are interesting for organic materials science and as photosensitizers in cancer phototherapy (PDT), because of their intense absorption in the visible region. Results show that the substitution at the bay position of the PDI parent molecule with N‐alkyl groups shifts the absorption maxima towards the red part of the visible spectrum (around 650–700 nm) as required for the applications in PDT. The main PDT action mechanisms have been investigated by computing of electron affinities, ionization potentials, triplet energies and spin‐orbit matrix elements between singlet and triplet excited states. © 2012 Wiley Periodicals, Inc.
Skill in Interviewing Reduces Confirmation Bias
Authors: Powell Martine B. , Hughes‐Scholes Carolyn H. , Sharman Stefanie J.
Published: February 2012

Interviewers given prior information are biassed to seek it from interviewees. We examined whether the detrimental impact of this confirmation bias in terms of leading question use was moderated by interviewers' demonstrated ability to adhere to open questions. We classified interviewers' adherence as ‘good’ or ‘poor’ in an independent interview before they interviewed children about a staged event. Half the interviewers were given biassing true and false information about the event; half were given no information. As predicted, only poor interviewers showed the effect of bias. Poor interviewers asked fewer open questions in the biassed condition than the non‐biassed condition; good interviewers asked the same (high) proportion of open questions in both conditions. Poor interviewers asked more leading questions in the biassed condition than the non‐biassed condition; good interviewers asked the same (low) proportion of leading questions in both conditions. These results demonstrate that interviewers' skill in adhering to open questions reduces the detrimental impact of confirmation bias on question type. Copyright © 2012 John Wiley & Sons, Ltd.
A case‐control comparison of lingual tonsillar size in children with and without down syndrome
Authors: Sedaghat Ahmad R. , Flax‐Goldenberg Renee B. , Gayler Bob W. , Capone George T. , Ishman Stacey L.
Published: February 2012

Objectives/Hypothesis:

Lingual tonsillar hypertrophy is a common cause of persistent obstructive sleep apnea following adenotonsillectomy in the pediatric population and may be more prevalent in patients with Down syndrome (DS). We sought to quantify lingual tonsil size in pediatric DS patients and compare these findings to those of nonsyndromic children using cervical spine (c‐spine) radiographs.

Study Design:

Case control study.

Methods:

Retrospective review of c‐spine radiographs from 105 pediatric DS patients and 89 age‐ and gender‐matched non‐DS controls was conducted. Films performed for possible airway compromise or trauma were excluded. Lingual tonsil size and narrowest lumen diameter of the nasopharynx, oropharynx, and hypopharynx were measured.

Results:

Radiographically identifiable lingual tonsillar tissue was identified in 34% of children with DS and 30% of controls (P = .21); lingual tonsillar hypertrophy (≥10 mm) was seen in 5% and 0% respectively (P = .074). Nasopharyngeal diameter was smaller in patients with DS compared to controls (5.2 mm vs. 6.3 mm, P = .026), whereas lingual tonsil size was significantly larger in DS patients (2.1 mm vs. 0.8 mm, P = .0008). In multivariate analysis, lingual tonsil size was positively correlated with increasing age in the DS population (r = 0.38, P < .0001) but not in controls.

Conclusions:

Lingual tonsillar enlargement is more common in patients with DS than in controls, with an increased prevalence in older DS patients. C‐spine radiographs are routinely carried out in these children and appear to be useful in identifying lingual tonsillar hypertrophy. Further trials should be carried out to compare c‐spine findings and physical exam or magnetic resonance imaging to validate this method of evaluation.
Balloon dilation of the eustachian tube in a cadaver model: Technical considerations, learning curve, and potential barriers
Authors: McCoul Edward D. , Singh Ameet , Anand Vijay K. , Tabaee Abtin
Published: February 2012

Objectives/Hypothesis:

The surgical management options for eustachian tube dysfunction have historically been limited. The goal of the current study was to evaluate the technical considerations, learning curve, and potential barriers for balloon dilation of the eustachian tube (BDET) as an alternative treatment modality.

Study Design:

Prospective preclinical trial of BDET in a cadaver model.

Methods:

A novel balloon catheter device was used for eustachian tube dilation. Twenty‐four BDET procedures were performed by three independent rhinologists with no prior experience with the procedure (eight procedures per surgeon). The duration and number of attempts of the individual steps and overall procedure were recorded. Endoscopic examination of the eustachian tube was performed after each procedure, and the surgeon was asked to rate the subjective difficulty on a five‐point scale.

Results:

Successful completion of the procedure occurred in each case. The overall mean duration of the procedure was 284 seconds, and a mean number of 1.15 attempts were necessary to perform the individual steps. The mean subjective procedure difficulty was noted as somewhat easy. Statistically shorter duration and subjectively easier procedure were noted in the second compared to the first half of the series, indicating a favorable learning curve. Linear fissuring within the eustachian tube lumen without submucosal disruption (nine procedures, 37%) and with submucosal disruption (five procedures, 21%) were noted. The significance of these physical findings is unclear.

Conclusions:

Preclinical testing of BDET is associated with favorable duration, learning curve, and overall ease of completion. Clinical trials are necessary to evaluate safety and efficacy. Laryngoscope, 2012
Normative diameters and effects of aging on the cochlear and facial nerves in normal‐hearing Korean ears using 3.0‐tesla magnetic resonance imaging
Authors: Kang Woo Seok , Hyun Sang Min , Lim Hyun Kyung , Shim Byoung Soo , Cho Jae Hyeong , Lee Kwang‐Sun
Published: February 2012

Objectives/Hypothesis:

To assess the normative size of the cochlear nerve (CN) and facial nerve (FN) in normal‐hearing ears and to determine whether nerve size varies with age.

Study Design:

Cross‐sectional.

Methods:

We included 169 ears with normal hearing between 2005 and 2010. The height, width, and cross‐sectional area (CSA) of the CN and FN in the middle of the internal auditory canal were measured on oblique sagittal images of 3.0‐T magnetic resonance imaging. Results were compared by age. Young subjects were divided into three age groups, 0–5, 6–10, and 11–15 years. Subjects over age 40 years were divided into groups at 10‐year intervals.

Results:

Mean age was 32.6 years (range, 0.75–79 years). We found that the CN had significantly greater vertical (1.10 ± 0.21 mm vs. 0.95 ± 0.21 mm) and horizontal (1.11 ± 0.20 mm vs. 1.03 ± 0.22 mm) diameters than the FN. The CSA of the CN was larger than that of the FN (0.98 ± 0.33 mm2 vs. 0.79 ± 0.31 mm2). Except for the CN vertical diameter, there were no significant differences between right and left ears. Sex did not affect the nerve size. Although the CN was not affected by age, the FN vertical diameter and CSA of children <5 years were significantly smaller than those of children aged >5 years. The size of the two nerves did not differ among groups over age 40 years.

Conclusions:

The CN is not affected by age in normal‐hearing ears. The FN vertical diameter and CSA of children <5 years are smaller than those of older children.
Investigation of the cochlear effects of intratympanic steroids administered following acoustic trauma
Authors: Ozdogan Fatih , Ensari Serdar , Cakir Ozgur , Ozcan Kursat Murat , Koseoglu Sabri , Ozdas Talih , Gurgen Seren Gulsen , Dere Huseyin
Published: February 2012

Objectives/Hypothesis:

To electrophysiologically and histomorphologically demonstrate the effects of intratympanic corticosteroids administered following an acoustic trauma on cochlear hair cells.

Methods:

The trial was performed on 16 Wistar albino rats. The rats underwent distortion product otoacoustic emissions (DPOAE) measurement before the acoustic trauma, and subsequently rats were exposed to noise. Following acoustic trauma, the otoacoustic emission measurement was repeated. The rats were divided into two groups, a study group and a control group. The study rats were injected with methylprednisolone via the intratympanic route throughout the study. In the control group, the rats were injected daily with saline. After performing repeated otoacoustic emission measurements, one rat in each of the groups was sacrificed and their cochleae isolated.

Results:

The histological investigation performed after the 1st week revealed a statistically significantly higher rate of apoptotic cells in the inner and particularly the outer hair cells of the rat cochleae in the control group compared to the study group. Early measurement of DPOAE within the 1st week demonstrated significantly better amplitudes in the study group compared to controls. The otoacoustic emission assessment performed on the 14th day demonstrated statistically similar DPOAE values between the two groups.

Conclusions:

Intratympanic methylprednisolone injection administered following an acoustic trauma appears to reduce cochlear outer hair cell loss. The impact on hearing loss is less certain. Early measurement of DPOAE within the 1st week shows significantly better amplitudes in the study group compared to controls. However at 2 weeks, there is no statistically significant difference in DPOAE amplitudes between the study and control group. Laryngoscope, 2012
Frontal sinus osteoma removal with the ultrasonic bone aspirator
Authors: Ehieli Eric , Chu Jaemi , Gordin Eli , Pribitkin Edmund A.
Published: February 2012

Osteomas, the most common skull tumors, are typically excised through either an open or endoscopic ostectomy using a high‐speed drill, a technically challenging procedure that can result in injury to adjacent soft tissue structures. Osteoma removal through ultrasonic bone emulsification and aspiration (UBA) offers the advantages of decreased blood loss, preservation of adjacent soft tissue structures, and precise bone removal. UBA was used to successfully remove a forehead osteoma without injury to adjacent nerves and with a satisfactory cosmetic outcome. We describe skull osteoma removal with an ultrasonic bone aspirator, which offers potential advantages over conventional bone removal techniques. Laryngoscope, 2012
How does measured olfactory function correlate with self‐ratings of the sense of smell in patients with nasal polyposis?
Authors: Nguyen Duc Trung , Nguyen‐Thi Phi‐Linh , Jankowski Roger
Published: February 2012

Objectives/Hypothesis:

The objectives of this study were to investigate correlations, before and after surgery, between olfactory function self‐ratings and measurements, and self‐ratings of nasal obstruction and smell; and to establish cutoff points of self‐rating scores for smell reduction in patients with nasal polyposis (NP).

Study Design:

Prospective study.

Methods:

A total of 80 patients with NP (36 women, 44 men; aged 49 ± 4 years) were enrolled. Self‐ratings (0‐ to 10‐point scale) and measurements of olfactory function with standardized Sniffin' Sticks odor threshold and identification tests were assessed 1 day before surgery, and at 6 weeks (26–78 days) and 7 months (132–318 days) after surgery. Relationships were studied with Spearman correlation coefficients. Cutoff points of self‐rating scores for olfactory deficit were established using the receiver operating characteristic curve.

Results:

Overall, olfactory function self‐ratings and measurements correlated strongly preoperatively (r = −0.66, P < .0001) and postoperatively (r = −0.67 at 6 weeks and −0.66 at 7 months, P < .0001). This relationship was better in patients with previous surgery. The correlation was weaker before surgery (r = −0.35, P = .01) than after in hyposmic/anosmic patients (r = −0.74, P < .0001 at 6 weeks and r = −0.73, P = .0002 at 7 months) and was not found in normosmic patients. Self‐ratings of nasal patency and smell were not correlated when two complaints were dissociated. Cutoff points of self‐rating scores for smell reduction were nine units preoperatively and five units postoperatively.

Conclusions:

Self‐ratings and measurements of olfactory function correlated well before and after surgery in NP patients with olfactory deficits. Self‐ratings were not reliable pre‐ and postoperatively in normosmic patients.
Effects of magnetic fields on the dynamic characteristics of wide parallel step slider bearings with electrically conducting fluids
Authors: Lin Jaw‐Ren , Lu Rong‐Fang , Hung Tzu‐Chen , Liang Long‐Jin
Published: February 2012

By the use of electrically conducting fluids as lubricants together with the application of externally magnetic fields, the dynamic lubrication problems of parallel step slider bearings lubricated with a nonconducting fluid are extended in this paper. A closed‐form solution has been derived for the magneto‐hydrodynamic characteristics of wide parallel step slider bearings. Comparing with the bearing lubricated with nonconducting fluids, the magneto‐hydrodynamic parallel step slider bearings signify an improvement in the load capacity, as well as the dynamic stiffness and damping coefficients. A numerical example and calculated values are also provided in tables for engineers in bearing selection and designing. Copyright © 2012 John Wiley & Sons, Ltd.
Involvement of GABAA receptors in myoclonus
Authors: Matsumoto Rae R. , Truong Daniel D. , Nguyen Kevin D. , Dang A. Terri , Hoang Tin T. , Vo Phi Q. , Sandroni Paola
Published: February 2012

Alterations in multiple neurochemical systems have been reported in animal and human studies of posthypoxic myoclonus. It is impossible, however, to establish causative relationships between the observed changes and the myoclonic movements from these studies. Therefore, to establish causative links between neurochemical changes and myoclonus, ligands that target neurotransmitter systems that are altered in posthypoxic myoclonus were microinjected into the lateral ventricles of normal rats to identify the changes that can produce myoclonus. Of the ligands that were tested, only the GABAA antagonists produced myoclonus after intracerebroventricular administration, suggesting the importance of disinhibition of GABAergic systems in myoclonus. To further examine the role of GABA in myoclonus, GABAergic antagonists were microinjected into the nucleus reticularis of the thalamus (NRT), an area of the brain in which extensive pathologic changes are seen in posthypoxic animals. GABAA, but not GABAB, antagonists produced myoclonus after microinjection into the NRT. Earlier investigators have further reported the ability of GABAA antagonists to produce myoclonus after microinjection into the caudate. The data therefore suggest that disruption of activity at GABAA receptors at any one of a number of levels in the neural axis can produce myoclonus.
The axial stability of the femur after harvest of the medial femoral condyle corticocancellous flap: A biomechanical study of composite femur models
Authors: Katz Ryan D. , Parks Brent G. , Higgins James P.
Published: February 2012

Purpose:

Free bone or periosteal flaps from the medial femoral condyle are being employed for treatment of recalcitrant nonunions. When harvested in a corticocancellous fashion, these flaps have the potential to compromise the stability of the femur. This study is designed to test the axial stability of the femur after harvest of corticocancellous flaps using a standardized composite femur model.

Methods:

Corticocancellous defects of standardized width and depth (2 cm × 1 cm) were designed with increasing length (3‐cm intervals extending from 3 to 24 cm) over the medial femoral condyle of five composite femur models. After harvest of each corticocancellous block, the femur was subjected to an axial force of 9100 N loaded and unloaded over one second using a Mini‐Bionix load frame. During the application of force, load and deformation data were collected from the load cell and linear variable differential transducer. To determine changes in stiffness or deformation with increasing flap sizes, analysis of variance with repeated measures was used. If the main effect was found to be significant, a Tukey's test was used to determine differences between specific flap sizes.

Results:

There were no femur fractures in any femurs for any flap size. Deformation during load increased as the size of the flap increased (2.19 mm ± 0.062 mm for the 3‐cm flap defect) to (2.33 mm ± 0.113 mm for the 24‐cm flap defect). Post‐hoc testing of deformation shows a statistically significant difference only between the 3‐cm flap defect and the 15‐cm flap defect (2.19 vs. 2.30 mm) (P = 0.002). The range of stiffness is between 4,339 and 4,697 N mm−1. Stiffness tends to decrease significantly (P < 0.001) with increasing flap size. Harvest of flap sizes greater or equal than 9 cm results in significantly lower stiffness compared to the 3‐cm flap.

Conclusions:

In this composite femur model, when stressed with supraphysiologic forces, the femur retains its axial stability even after harvest of large corticocancellous flaps from its medial aspect. Statistical significance detected in deformation and stiffness may not be clinically relevant if the femur does not fracture after flap harvest. Such was the case in this experiment. The possibility exists of safely harvesting large flaps from this donor site. Corticocancellous flaps from the medial aspect of the femur may serve as an alternative to standard flaps used in medium and large osseous reconstructions. The size of flap that can be safely raised without compromising the stability of the femur has not yet been delineated. © 2012 Wiley Periodicals, Inc. Microsurgery, 2012.
The first integral method for constructing exact and explicit solutions to nonlinear evolution equations
Authors: Aslan Ísmail
Published: February 2012

Problems that are modeled by nonlinear evolution equations occur in many areas of applied sciences. In the present study, we deal with the negative order KdV equation and the generalized Zakharov system and derive some further results using the so‐called first integral method. By means of the established first integrals, some exact traveling wave solutions are obtained in a concise manner. Copyright © 2012 John Wiley & Sons, Ltd.
MR imaging near metal with undersampled 3D radial UTE‐MAVRIC sequences
Authors: Carl Michael , Koch Kevin , Du Jiang
Published: February 2012

Recently developed techniques such as the multiple acquisition with variable resonance image combination and slice encoding for metal artifact correction techniques have improved the ability of clinical magnetic resonance scanners to image near metal implants. These sequences are based on fast spin echo sequences which preclude detection of short T2 tissues such as tendons, ligaments, and cortical bone. Ultrashort echo time sequences have the potential to detect signals from these tissues. In this study, we investigate the potential of combining ultrashort echo time with multiple acquisition with variable resonance image combination to image short T2 musculoskeletal tissues adjacent to metallic implants. Different radio frequency excitation pulse types and spectral binning strategies were studied. We found that ultrashort echo time‐multiple acquisition with variable resonance image combination sequences were able to significantly reduce typical artifacts near metal, as well as detect very short T2 signals that are usually not visualized using clinical pulse sequences. Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc.
Enhanced electrical and mechanical properties of multiwall carbon nanotube rubber composites
Authors: Bokobza Liliane
Published: February 2012

Multiwall carbon nanotube‐filled elastomers are prepared by solution blending using a sonication process. It is shown that the processing conditions have a strong effect on the composite properties especially on electrical properties, which are very sensitive to nanotube dispersion within the elastomeric matrix. The percolation threshold is seen to be shifted to a lower nanotube content than that previously reported. With regard to the unfilled elastomer, large increases in the elastic and tensile moduli are obtained with the nanotube loading, thus highlighting the potential of this type of particles as reinforcing fillers for elastomeric matrices. Raman spectroscopy under strain has been used to evaluate the strength of the polymer–filler interface. Weak interfacial interactions are deduced, but the debundling of the nanotubes and the orientational effects of the polymeric chains are observed when the composite is submitted to a uniaxial deformation. Copyright © 2012 John Wiley & Sons, Ltd.
Oestrogen attenuates tumour progression in hepatocellular carcinoma
Authors: Xu Hanwen , Wei Yinna , Zhang Yu , Xu Yichen , Li Feng , Liu Jing , Zhang Wei , Han Xiaodong , Tan Renxiang , Shen Pingping
Published: February 2012

The precise mechanisms underlying gender disparity in hepatocellular carcinoma (HCC) progression and prognosis are not understood. We demonstrate that oestrogen attenuates HCC progression in vitro and in vivo, and this may contribute to the gender differences in HCC behaviour. To investigate the role of oestrogen in HCC progression, we developed an orthotopic homograft tumour model by liver implantation of H22 cells. In combination with male castration, female ovariectomy, and oestrogen treatment, we tested the hypothesis that oestrogen contributes to gender disparity in this model. Pathological analyses were performed to examine the changes in biological behaviour of liver cancer cells, and two cell lines were used to investigate possible molecular mechanisms of the suppressive effect of oestrogen. Our data showed that oestrogen modulates HCC malignancy in vivo by reducing tumour cell invasion, arresting cell cycle progression, and promoting apoptosis, characterized by decreased expression of MMP‐2, MMP‐9, PCNA, cyclin A, cyclin D1, and Bcl‐2, and increased expression in cleaved caspase 3. Through in vitro assays, we further confirmed the changes in expression levels of these related proteins, gained insights into the molecular cascades of oestrogen‐induced HCC suppression, and indicated the oestrogen receptor α‐mediated inhibition of NF‐κB binding activity as a pivotal event in this process. This study represents a novel description of the mechanisms regarding the suppressive effects of oestrogen on HCC, adding a new understanding to the gender disparity in HCC progression. Copyright © 2012 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Isolation of Quaternary Benzo[c]phenanthridine Alkaloids from Macleaya microcarpa ( maxim.) fedde: Comparison of Maceration, Soxhlet Extraction and Pressurised Liquid Extraction
Authors: Urbanová Jana , Pěnčíková Kristýna , Gregorová Jana , Hohnová Barbora , Šťavíková Lenka , Karásek Pavel , Roth Michal , Táborská Eva
Published: February 2012

Introduction

Macleaya microcarpa (Papaveraceae family) has been of considerable interest in recent years as a prospective source of quaternary benzo[c]phenanthridine alkaloids (QBAs) related to many pharmaceutical beneficial effects. For this purpose, a quantitative, efficient and fast method to isolate the QBAs from the plant material is required.

Objective

To optimise and compare pressurised liquid extraction (PLE) with Soxhlet extraction and maceration in order to estimate extraction conditions for fast and efficient isolation of QBAs contained in the roots of Macleaya microcarpa.

Methodology

The QBAs were extracted by PLE, Soxhlet extraction and maceration at different conditions (solvent, time, etc.). Reversed phase HPLC with diode‐array detector was utilised for their determination and quantification. To optimise the PLE procedure, the variable parameters, including temperature (40–150 °C), sample‐to‐inert material ratio, extraction time (5–30 min) and number of extraction cycles (1–4), were also tested.

Results

Quantitative determination of QBAs resulted in 0.2–2.8 mg/g, 0.3–2.5 mg/g and 0.3–3.1 mg/g for PLE, Soxhlet extraction and maceration. To produce the yields mentioned above, PLE required only up to 30 min compared with 21 h for Soxhlet extraction and 49 days for maceration.

Conclusion

PLE provided an effective and fast extraction of QBAs from M. microcarpa roots and can be recommended as an alternative isolation method to conventional techniques for QBAs from the plant sources. Copyright © 2012 John Wiley & Sons, Ltd.
Drug‐induced Stevens–Johnson syndrome: case series from tertiary care centre in Gujarat
Authors: Bang Damodar , Shah Tapan , Thakker Divyesh , Shah Yogesh , Raval Amit D.
Published: February 2012

Purpose

The aims of the present article were to study clinical features and to analyse them in different drug class associated with Stevens–Johnson syndrome (SJS) in a tertiary care hospital in Gujarat, India.

Materials and Methods

A prospective hospital‐based study was carried out over a period of 3 years (June 2007 to September 2009) at Sheth Vadilal Hospital, Ahmedabad, India. The diagnosis of SJS was made mainly on the basis of the clinical findings, which included extensive erythema multiforme, purpuric lesions with bullae and detachment of skin involving at least two mucous membranes. Further, in each patient suspected with SJS, various laboratory tests such as complete blood count, liver function tests, metabolic panel, chest X‐ray and other serological test were carried out. SJS was confirmed on the basis of most widely accepted Bastuji‐Garin definition. Causality assessment was performed using the Naranjo scale. Only ‘probable’ and ‘definite’ reactions were included.

Results

Antibacterials for systemic use, anti‐inflammatory and antirheumatic products and antiepileptics were the drug classes most commonly associated (8 of 29 cases, each) with SJS. Individually, ibuprofen was involved in the highest number of cases (five cases, 17.2%), followed by carbamazepine (four cases, 13.8%) . The mean duration of developing SJS symptoms was 15.9 days (SD = 8.7 days) and improvement after treatment was 14.2 days (SD = 4.6 days). The duration of appearing SJS symptoms varied significantly between different classes of drugs (p < 0.001). The appearance of SJS symptom started within 10 days for anti‐inflammatory and antibacterial compared with 24 days of antiepileptic agents. All the patients with antiepileptic agent–induced SJS had 7% to 9% of detached body surface area. In two patients, SJS progressed to toxic epidermal necrolysis and of which one led to death and the other developed long‐term complication of conjunctival xerosis. A total of six patients developed long‐term complications: four patients had conjunctival synechia, one patient had conjunctival xerosis and one patient had urethral stricture.

Conclusion

More than 80% of the SJS events were induced by antibacterial, anti‐inflammatory and antiepileptic agents with same frequency. The duration of the appearance of SJS symptoms significantly varied between different drug classes and started within 10 days for anti‐inflammatory and antibacterial compared with 24 days of antiepileptic agents. Copyright © 2012 John Wiley & Sons, Ltd.
Structural basis of RNA binding by leucine zipper GCN4
Authors: Nikolaev Yaroslav , Pervushin Konstantin
Published: February 2012

Recently, we showed that leucine zipper (LZ) motifs of basic leucine zipper (bZIP) transcription factors GCN4 and c‐Jun are capable of catalyzing degradation of RNA (Nikolaev et al., PLoS ONE 2010; 5:e10765). This observation is intriguing given the tight regulation of RNA turnover control and the antiquity of bZIP transcription factors. To support further mechanistic studies, herein, we elucidated RNA binding interface of the GCN4 leucine zipper motif from yeast. Solution NMR experiments showed that the LZ‐RNA interaction interface is located in the first two heptads of LZ moiety, and that only the dimeric (coiled coil) LZ conformation is capable of binding RNA. Site‐directed mutagenesis of the LZ‐GCN4 RNA binding interface showed that substrate binding is facilitated by lysine and arginine side chains, and that at least one nucleophilic residue is located in proximity to the RNA phosphate backbone. Further studies in the context of full‐length bZIP factors are envisaged to address the biological relevance of LZ RNase activity.
The contribution of different prion protein types and host polymorphisms to clinicopathological variations in Creutzfeldt–Jakob disease
Authors: Head Mark W. , Ironside James W.
Published: February 2012

Creutzfeldt–Jakob disease is a fatal neurodegenerative disease that primarily affects the central nervous system. In this respect, it can be considered alongside the more frequently occurring neurodegenerative diseases, such as Alzheimer's disease. Creutzfeldt–Jakob disease is perhaps the paradigmatic protein misfolding disorder, so comparisons between the mechanisms involved in Creutzfeldt–Jakob disease and other neurodegenerative diseases associated with protein misfolding (such as the tauopathies and synucleinopathies) may also be informative. Like many of these diseases, Creutzfeldt–Jakob disease occurs sporadically or can, more rarely, be associated with mutations. However, Creutzfeldt–Jakob disease can also be acquired and is experimentally transmissible. These properties have had profound public health implications and made the disease of interest to virologists, in addition to those interested in protein misfolding disorders and neurodegeneration. The possible causes for the pronounced phenotypic variation among different forms of Creutzfeldt–Jakob disease are beginning to become understood, and these appear to depend in large measure on the genetics of the host (specifically the sequence of the prion protein gene, PRNP) and the epigenetic aspects of the agent (thought to be a misfolded and aggregated form of the PRNP gene product, termed a prion). This review will examine whether this model in its present form has sufficient complexity and subtlety to account for the clinicopathological variation evident in Creutzfeldt–Jakob disease and will outline the ways in which a more complete and informative molecular definition of human prions are currently being sought. Copyright © 2012 John Wiley & Sons, Ltd.
On the evolution of Linux kernels: a complex network perspective
Authors: Wang Lei , Yu Pengzhi , Wang Zheng , Yang Chen , Ye Qiang
Published: February 2012

This paper presents a novel method to study the evolution of Linux kernel components using complex networks to understand how Linux kernel components evolve over time. After analyzing the node degree distribution, clustering coefficient, and average path length of the call graphs corresponding to the kernel components of 130 development versions and 94 stable versions (V1.0 to V2.4.35), we found that the call graphs of the file system, driver, kernel, memory management, and net components are scale‐free, small‐world complex networks. In addition, all of the five components exhibit very strong preferential attachment tendency. With such in‐depth understanding of the features of the Linux kernel components, we propose a generic method that could be used to find major structural changes that occur during the evolution of software systems. Copyright © 2012 John Wiley & Sons, Ltd.