bluuebunny/crossref_metadata_2025 huggingface dataset:
A new crack tip element for the phantom‐node method with arbitrary cohesive cracks
Authors: Rabczuk Timon , Zi Goangseup , Gerstenberger Axel , Wall Wolfgang A.
Published: January 2008

We have developed a new crack tip element for the phantom‐node method. In this method, a crack tip can be placed inside an element. Therefore, cracks can propagate almost independent of the finite element mesh. We developed two different formulations for the three‐node triangular element and four‐node quadrilateral element, respectively. Although this method is well suited for the one‐point quadrature scheme, it can be used with other general quadrature schemes. We provide some numerical examples for some static and dynamic problems. Copyright © 2007 John Wiley & Sons, Ltd.
Comparison of symptomatology in Taiwanese women pregnant with and without assisted reproductive technology
Authors: Kuo Pi‐Chao , Chu Nancy L. , Chen Yueh‐Chih , Su Tsann‐Jun , Chen Chung‐Hey
Published: January 2008

We compared the symptoms of 91 Taiwanese women, 50 pregnant by assisted reproductive technology (ART), with those of 41 women, pregnant without assistance. They completed a self‐administered demographic questionnaire and symptomatology inventory (SI) during each trimester. The ART group had a higher frequency of complications and hospitalizations than the unassisted women. No significant differences were found in physical and affective symptoms in the ART group across three trimesters, but significant differences were found in the unassisted group. In addition, ART and non‐ART women differed in types of individual symptoms experienced each trimester. These findings suggest the need for nurses to assess each group for the presence of specific symptoms throughout pregnancy and to provide individualized symptom management. © 2008 Wiley Periodicals, Inc. Res Nurs Health 31:208–216, 2008
Is there a bias against telephone interviews in qualitative research?
Authors: Novick Gina
Published: January 2008

Telephone interviews are largely neglected in the qualitative research literature and, when discussed, they are often depicted as a less attractive alternative to face‐to‐face interviewing. The absence of visual cues via telephone is thought to result in loss of contextual and nonverbal data and to compromise rapport, probing, and interpretation of responses. Yet, telephones may allow respondents to feel relaxed and able to disclose sensitive information, and evidence is lacking that they produce lower quality data. This apparent bias against telephone interviews contrasts with a growing interest in electronic qualitative interviews. Research is needed comparing these modalities, and examining their impact on data quality and their use for studying varying topics and populations. Such studies could contribute evidence‐based guidelines for optimizing interview data. © 2008 Wiley Periodicals, Inc. Res Nurs Health 31:391–398, 2008
Knock‐in murine models of familial gastrointestinal stromal tumours
Authors: Gunawan B
Published: January 2008

In recent years, gastrointestinal stromal tumour (GIST) has emerged from a poorly understood group of mesenchymal tumours to a distinct pathological entity that has become a leading model for new therapies targeting kinases. GIST pathogenesis is driven by receptor tyrosine kinase‐activating mutations most often in KIT or PDGFRA that may be sporadic or result in familial GIST syndromes. In a recent issue of The Journal of Pathology (J Pathol 2008;214:302–311), Nakai and colleagues report that mutation of the previously un‐modelled tyrosine kinase II domain of KIT generates a spectrum of features very similar to that in two human GIST families. Knock‐in mouse models of GIST may prove extremely useful in pre‐clinical evaluation of kinase‐targeted compounds and of the mechanism of drug resistance, but intriguingly it now seems clearer that the distribution of GIST in mouse models and humans is different. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Increased MMP‐2 activity during intervertebral disc degeneration is correlated to MMP‐14 levels
Authors: Rutges JPHJ , Kummer JA , Oner FC , Verbout AJ , Castelein RJM , Roestenburg HJA , Dhert WJA , Creemers LB
Published: January 2008

Intervertebral disc (IVD) degeneration is associated with the increased expression of several matrix metalloproteinases (MMPs), in particular MMP‐2. However, little is known about the actual activity of MMP‐2 in healthy and degenerated discs, or what mechanisms are involved in its activation. A major activation pathway involves complex formation with MMP‐14 and a tissue inhibitor of metalloproteinases‐2 (TIMP‐2). In a series of 56 human IVDs, obtained at autopsy and graded according to the Thompson score (I–V), we analysed whether MMP‐2 activity was increased in different stages of IVD degeneration and to what extent activation was related to the production of MMP‐14 and TIMP‐2. MMP‐2 activation and production were quantified by gelatin zymography. Immunohistochemical staining of MMP‐14 and TIMP‐2 was quantified with a video overlay‐based system. A positive correlation was observed between the amount of active MMP‐2 and pro‐MMP‐2 and degeneration grade (p < 0.001, correlation coefficient (CC) 0.557; and p < 0.001, CC 0.556, respectively). MMP‐2 activity correlated positively with MMP‐14 and less strongly with TIMP‐2 (p = 0.001, CC 0.436; and p = 0.03, CC 0.288, respectively). Moreover, immunopositivity for MMP‐14 correlated to degeneration grade (p = 0.002, CC 0.398). IVD degeneration was associated with the activity of MMP‐2 and the correlation of its activation with MMP‐14 production suggests MMP‐14 activates MMP‐2 during degeneration. As MMP‐14 is capable of activating several other enzymes that are also thought to be involved in IVD degeneration, it may be a key mediator of the degenerative process. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Application of analytical and preparative high‐speed counter‐current chromatography for the separation of Z‐ligustilide from a crude extract of Angelica sinensis
Authors: Wang Xiao , Shi Xingang , Li Fuwei , Liu Jianhua , Cheng Chuange
Published: January 2008

Z‐Ligustilide was separated and purified from the traditional Chinese medicinal plant Angelica sinensis by high‐speed counter‐current chromatography (HSCCC). Analytical HSCCC was first used for the systematic selection of the two‐phase solvent system. Preparative HSCCC separation was performed with a two‐phase solvent system composed of petroleum ether (60–90°C)–ethanol–water at an optimum volume ratio of 10:17:10 (v/v). A total of 38 mg Z‐ligustilide at 98.8% purity was obtained in one step from 200 mg crude extract as determined by HPLC analysis. The structure of the target compound was identified by electron impact ionisation mass spectrometry. Copyright © 2008 John Wiley & Sons, Ltd.
Validated method for the quantification of artepillin‐C in Brazilian propolis
Authors: Matsuda Adriana Hitomi , de Almeida‐Muradian Ligia Bicudo
Published: January 2008

Brazilian propolis contains several phenolic compounds among which 5 diprenyl‐4‐hydroxycinnamic acid (artepillin‐C) is commonly found in areas where flora is rich in Baccharis species. The quantification of artepillin‐C has become an important factor as an indicator of Brazilian propolis quality and the compound may be used as a chemical marker for quality control in exportating green propolis. This work was to validate the method and evaluate the content of artepillin‐C from 33 samples collected in different Brazilian regions. The method used was HPLC with UV–vis detection and a reversed‐phase C18 column. The validation parameters studied were: linearity, accuracy, precision, quantification and detection limits. The results obtained were: detection limit = 0.0036 µg/mL, quantification limit = 0.012 µg/mL, accuracy = 0.0064 and 0.078, recovery 98–102%. Artepillin‐C content varied from 0 to 11% depending on the geographical origin. Propolis from the southeast region presented the highest level of artepillin‐C (5.0–11.0%). Whist that from the northeast region did not show any artepillin‐C. Copyright © 2008 John Wiley & Sons, Ltd.
Outpatient use of cardiovascular drugs during pregnancy
Authors: Andrade Susan E. , Raebel Marsha A. , Brown Jeffrey , Lane Kimberly , Livingston James , Boudreau Denise , Rolnick Sharon J. , Roblin Douglas , Smith David H. , Dal Pan Gerald J. , Scott Pamela E. , Platt Richard
Published: January 2008

Purpose

To provide information on the prevalence of use of cardiovascular drugs, some of which may have fetotoxic or teratogenic effects, in the outpatient setting among pregnant women in the United States.

Methods

A retrospective study was conducted using the automated databases of seven health plans participating in the HMO Research Network Center for Education and Research on Therapeutics (CERT). Women who delivered an infant from 1 January 2001 to 31 December 2005 were identified. Cardiovascular drug use was evaluated assuming a gestational duration of 270 days.

Results

During the period 2001 through 2005, 118 935 deliveries were identified that met the criteria for study; 3.1% of women (N = 3672) were dispensed an antihypertensive medication and 0.12% of women (N = 146) were dispensed an antihyperlipidemic medication at any time during pregnancy. The most common antihypertensive drugs dispensed during pregnancy were nifedipine (1219 deliveries; 1.0%), methyldopa (961 deliveries; 0.8%), atenolol (593 deliveries; 0.5%), and labetalol (576 deliveries; 0.5%). Overall, 134 women (0.11%) received an angiotensin converting enzyme (ACE) inhibitor and 7 women (0.006%) received an angiotensin II receptor blocker (ARB) during pregnancy. Statins were the most commonly dispensed antihyperlipidemic drugs (71 deliveries; 0.06%).

Conclusions

The prevalence of use of cardiovascular drugs that are suspected to be fetotoxic or teratogenic (ACE inhibitors, ARBs, and statins) was low in this cohort of pregnant women. Differing patterns of use across health plans suggests that further research is needed to evaluate the potential differential effects of cardiovascular drugs to assist prescribers and patients in making informed treatment decisions. Copyright © 2008 John Wiley & Sons, Ltd.
Calibration of the WCT‐100 photoconductance instrument at low conductance
Authors: McIntosh Keith R. , Guo Jiun‐Hua , Abbott Malcolm D. , Bardos Robert A.
Published: January 2008

The WCT‐100 photoconductance instrument is used throughout the photovoltaic industry providing a relatively simple and inexpensive means to assess recombination parameters. This paper presents a method to determine its output voltage VWCT over the conductance range, S = 0·002–20 mS, a range not easily attained by the conventional calibration method. The relationship between VWCT and S is found to transition from being non‐linear to linear at S ∼ 1 mS, which equates to the conductance of a 300 µm thick 30 Ω‐cm silicon wafer. For samples whose dark conductance is lower than the transition conductance, the non‐linear relationship between VWCT and S must be taken into account to prevent a gross underestimation of recombination rate. The method we describe can equally well be used to investigate the calibration of other photoconductance instruments. It involves the simultaneous measurement of a device's electrical conductance and the instrument's output voltage under a range of steady‐state illumination intensities. Copyright © 2008 John Wiley & Sons, Ltd.
High voltage photovoltaic mini‐modules
Authors: Ortega Pablo , Bermejo Sandra , Castañer Luis
Published: January 2008

This work describes the design, simulation, fabrication process, and characterization of high voltage photovoltaic mini‐modules using silicon on insulator (SOI) wafers. The mini‐modules are made of a number of small area photovoltaic cells (<1 mm2) monolithically connected in series. Isolation between cells is performed by means of anisotropic etching of the active layer of the SOI wafer. Measurements using standard sunlight (AM1·5 100 mW/cm2) confirm the viability of this technology to fabricate small area arrays showing open circuit voltages,Voc, between 620 mV and 660 mV and photocurrent densities up to 22·3 mA/cm2for single cells of 0·225 mm2area and 10 µm active film thickness. Series connection scales upVocand the maximum power,Pm, from 625 mV and 21·2 µW, respectively, in a single cell to 103 V and 3·2 mW when 169 cells are connected in series in a 0·42 cm2module total area. Copyright © 2008 John Wiley & Sons, Ltd.
Insights into environmental bioremediation by microorganisms through functional genomics and proteomics
Authors: Zhao Bing , Poh Chit Laa
Published: January 2008

Environmental pollutants in the soil are a major concern worldwide. Bioremediation mediated by microorganisms is a highly promising technology that is environmentally friendly, safe, and effective. However, incomplete biological information regarding the cellular responses in many microbial communities restricts progress in the site‐specific mineralization process. The application of proteomics in environmental bioremediation research provides a global view of the protein compositions of the microbial cells and offers a promising approach to address the molecular mechanisms of bioremediation. With the combination of proteomics, functional genomics provide an insight into global metabolic and regulatory networks that can enhance the understanding of gene functions. This article deals with the applications of functional genomics and proteomics to dissect the cellular responses to environmental stimuli, such as stress response, induction and expressions of regulatory proteins/enzymes in response to aromatic hydrocarbons and heavy metals. An understanding of the growth conditions governing the expression of the proteome (for example, enzymes and regulatory proteins of aromatic hydrocarbon degradation, energy generation pathways, transport and stress‐related proteins) in a specific environment is essential for developing rational strategies for successful bioremediation.
Indirect carbon–carbon spin–spin couplings across one, two and three bonds in pyridine and diazine systems: experiment and theory
Authors: Witanowski Michal , Kamieńska‐Trela Krystyna , Biedrzycka Zenobia , Bechcicka Magdalena
Published: January 2008

An excellent linear correlation is found between a large body of experimental spin–spin carbon–carbon couplings, J(CC), across one, two and three bonds in pyridine and diazine ring systems and the corresponding B3PW91/6‐311++G(d,p)//B3PW91/6‐311++G(d,p) computations. The correlation does not differ significantly from the simplest relationship possible, J(CC)exp. = J(CC)calcd., within a small and random spread of about 1 Hz. There are 276 experimental values considered, and 124 out of these are new and come from the present work. The aromatic carbon–carbon couplings vary from −7.6 through +78.5 Hz. It is shown that the correlation provides a reliable tool for predictions of the signs of aromatic J(CC)'s even if the magnitudes of the latter are of the order of 1 Hz. It is demonstrated, for the first time, that the relatively weak 2
J(CC) couplings, in the heteroaromatic systems studied, can bear either sign and span a considerable range of about 11 Hz. The character of the correlation indicates that rovibronic effects on aromatic J(CC)'s and those of nuclear motions on aromatic J(CC)'s are practically negligible. All of this is in a perfect agreement with our recent extensive studies on aromatic J(CC)'s in analogous benzene ring system. Substituent effects on the aromatic J(CC)'s turn out to be significant not only for 1J(CC)'s but also for most of 3J(CC)'s and 2
J(CC)'s, and the computation neatly reciprocates these trends. Copyright © 2008 John Wiley & Sons, Ltd.
Theoretical evidence on O–N type smiles rearrangement mechanism: a computational study on the intramolecular cyclization of N‐methyl‐2‐(2‐chloropyridin‐3‐yloxy)‐acetamide anion
Authors: Sun Hui , Li Jinghua , Zhang Dongju , Ma Chen , Liu Chengbu
Published: January 2008

Smiles rearrangement (SR) falls under a broad category of organic synthesis for many important compounds. A complete understanding toward SR process appeals to the assistance of theoretical research. Herein, by performing quantum chemistry calculations, we give a theoretical evidence for the mechanism of a representative O–N type SR, the intramolecular cyclization of N‐methyl‐2‐(2‐chloropyridin‐3‐yloxy)acetamide anion. It is found that the SR to the ipso‐position involves a two‐step mechanism and is energetically more favorable than the direct nucleophilic attack by N atom on the ortho‐position. The present result rationalizes well the experimentally observed ipso‐SR product and provides a consistent picture of the O–N SR process. Copyright © 2008 John Wiley & Sons, Ltd.
Dissipation and movement of flumioxazin in soil at four field sites in Chile
Authors: Alister Claudio , Rojas Sandra , Gómez Patricio , Kogan Marcelo
Published: January 2008

BACKGROUND: Flumioxazin is a soil‐applied herbicide recommended for broadleaf weed control in soybeans and peanuts, and was recently introduced for vineyard weed management. Considering the limited information available in relation to flumioxazin field soil behaviour, the main objectives of this study were to determine the persistence, adsorption and movement of flumioxazin in soil in four Chilean vineyard production areas.

RESULTS: DT50 values ranged from 10.6 ± 1.0 to 32.1 ± 3.1 days between localities, being correlated with rain events, time between herbicide application and first heavy rain event, and soil pH. Flumioxazin soil residue found at 90 days after application (DAA) varied from 9.6 to 24.9% of the initial amount applied, and depended on the total rainfall amount that occurred during the first 90 DAA. Herbicide leaching below 15 cm was approximately 45% of the flumioxazin detected at 90 DAA in the whole soil profile. Flumioxazin maximum leaching soil depth was 45 cm at all locations. Kd values varied from 2.54 to 6.51 mg L−1, depending on localities and soil profile depth, and correlated positively with organic carbon and clay content.

CONCLUSIONS: These results indicate that flumioxazin is a herbicide with low environmental risk owing to its short DT50, reduced soil residues 3 months after application and low effective dose. Copyright © 2008 Society of Chemical Industry
The requirement for the inclusion of formulation efficacy trials in pesticide preregistration evaluations
Authors: Moreno Josefa , Falcó José V , Oltra María T , Jiménez Ricardo
Published: January 2008

BACKGROUND: Optimization of biocide use could serve to reduce the risks of biocides on human health. To optimize the risk/benefit ratio, it is important to develop procedures for evaluating the efficacy of biocide formulations. The authors examined the effectiveness of ten pyrethroid insecticide aerosol formulations registered for the household control of flies. Tests were performed using adult Musca domestica L. Knockdown effects and mortality were measured in a test chamber using the manufacturer's recommended discharge time.

RESULTS: The knockdown effect varied greatly between aerosols of similar composition. The knockdown 15 min post‐treatment was 66–98% for flies placed 120 cm above floor level and 53–96% for flies placed at a height of 180 cm. The KDT50 values ranged from 2.5 to 9.2 min for flies placed at 120 cm and from 3.2 to 12 min for flies placed at 180 cm. The highest rates of mortality were obtained for a formulation containing S‐bioallethrin, permethrin and piperonyl butoxide (81% at 120 cm and 79% at 180 cm).

CONCLUSION: Formulations similar in insecticide composition exhibit significant differences in efficacy. Consequently, insecticidal efficacy preregistration evaluations should address not only the efficacy of the active ingredient but also the effectiveness of the formulation. Copyright © 2008 Society of Chemical Industry
GLP‐1 C‐terminal structures affect its blood glucose lowering‐function
Authors: Li Yuan , Shi Changhong , Lv Qiujun , Zhang Huming , Li Biehu , Bian Guangxing , Huang Qingsheng , Zhang Weihua , Xue Xiaoping , Ren Xin , Gao Hua , Sun Chunyi , Wang Juan , Zhang Mingjie
Published: January 2008

Glucagon‐like peptide‐1 (GLP‐1), which is an endogenous insulinotropic peptide that can stimulate islet cells to secret insulin, is a promising new drug candidate for the treatment of type 2 diabetes. However, due to the very short half‐life of this peptide, the clinical value of GLP‐1 is restricted. A GLP‐1 peptide analog that had been altered by deletion of five amino acids from the C‐terminus (sGLP‐1) was selected and investigated in vivo for the therapeutic effect on GK rats with type II DM (T2DM). The results revealed that sGLP‐1 exhibited decreased blood glucose‐lowering ability compared to GLP‐1 in the first week, as measured after once‐daily administration. However, after drug administration for 2 weeks, the blood glucose‐lowering effect of sGLP‐1 became superior to that of GLP‐1. sGLP‐1 reduced apoptosis of the old islets, enhanced insulin production, and promoted new islets replication. sGLP‐1 is a shorter but more efficient GLP‐1 analog for type 2 diabetes management. Because sGLP‐1 prolonged the proliferation and recovery of islet cells, the ability to maintain blood glucose (BG) within a normal range was still present 2 weeks after drug withdrawal. These results confirmed the importance of the C‐terminus of GLP‐1 molecule, and further demonstrated that GLP‐1 (7–37) can be truncated till the 32nd amino acid to have a better long‐term BG lowing function. This result may imply for the presence of glucagon family clearance receptors in vivo and demonstrates that the C‐terminus participates in GLP‐1 clearance. Copyright © 2008 European Peptide Society and John Wiley & Sons, Ltd.
Prediction of giant antiferromagnetic coupling in exotic fluorides of AgII
Authors: Jaroń Tomasz , Grochala Wojciech
Published: January 2008

We show, using Density Functional Theory (DFT) calculations, that compressed AgF2 should turn above 17 GPa into a layered narrow‐gap material with a huge intralayer antiferromagnetic (AFM) coupling constant, reminiscent of those seen for parent copper (II) oxides (e.g., La2CuO4). Compressed AgF2 is thus the first candidate for the non‐oxocuprate two‐dimensional antiferromagnet. Calculations indicate that AgF2 could subsequently be metallised above 38 GPa, likely giving rise to superconductivity (SC).

magnified image

(© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Cost‐ and time‐effective three‐dimensional bone‐shape reconstruction from X‐ray images
Authors: Gunay Murat , Shim Mun‐Bo , Shimada Kenji
Published: January 2008

Background

Three‐dimensional (3D) bone shapes need to be created for visualization and pre‐operative surgery planning. Conventionally such shape data is extracted from volumetric data sets, obtained by three‐dimensional sensors, such as computerized tomography (CT) and magnetic resonance imaging (MRI). This conventional method is highly labor intensive and time consuming.

Methods

This paper presents a cost‐ and time‐effective computational method for generating a 3D bone shape from multiple X‐ray images. Starting with a predefined 3D template bone shape that is clinically normal and scaled to an average size, our method scales and deforms the template shape until the deformed shape gives an image similar to an input X‐ray image when projected onto a two‐dimensional (2D) plane. The hierarchical freeform deformation method is used to scale and deform the template bone. The problem of finding the 3D shape of the bond is reduced to a sequence of optimization problems. The objective of this optimization is to minimize the error between the input X‐ray image and the projected image of the deformed template shape. The sequential quadratic programming (SQP) is used to solve this multi‐dimentional optimization problem.

Results

The proposed X‐ray image‐based shape reconstruction is more computationally efficient, cost‐effective and portable compared to the conventional CT‐ or MRI‐based methods. Within a couple of minutes with a standard personal computer, the proposed method generates a 3D bone shape that is sufficiently accurate for many applications, such as (a) making a 3D physical mock‐up for training and (b) importing into, and using in, a computer‐aided planning system for orthopedic surgery, including bone distraction and open/closed wedge osteotomy.

Conclusions

Because the proposed method requires only a small number of X‐ray images and a minimum input from the user, the method can serve as a cost‐ and time‐effective 3D bone shape reconstruction method for various medical applications. Copyright © 2008 John Wiley & Sons, Ltd.
Computer‐assisted tibia preparation for total ankle arthroplasty: a cadaveric study
Authors: Adams Samuel B. , Spritzer Charles E. , Hofstaetter Stefan G. , Jakoi Andre M. , Pietrobon Ricardo , Nunley II James A. , Easley Mark E.
Published: January 2008

Background

Most surgeons performing total ankle arthroplasty (TAA) suggest that accurate tibial preparation perpendicular to the tibial shaft axis improves outcomes. Recent studies demonstrate that computerized surgical navigation significantly improves the accuracy of tibial preparation in total knee arthroplasty (TKA).

Methods

We performed the tibial preparation for TAA in seven matched pairs of cadaver lower extremities. One set of matched pairs was prepared using the conventional external tibial alignment guide/cutting block from the Scandanavian Total Ankle Replacement system (STAR, Waldemar Link GmbH & Co., Hamburg, Germany) under fluoroscopic guidance. The second set of matched pairs was prepared using the VectorVision® navigation system (BrainLAB, Munich, Germany), with currently available computed tomography (CT)‐based TKA software. Pre‐operative CT data were used to assess the tibial mechanical axis. In both groups, accuracy of the tibial plafond preparation relative to the tibial shaft axis in both the coronal and sagittal planes was determined by fluoroscopic, radiographic and CT analysis.

Results

Mean values of the tibial cut for the set of matched‐pair tibiae prepared by the conventional surgical method ranged across the three imaging assessment techniques in the ranges 89.3–89.6° (coronal plane, anteroposterior) and 90.3–90.4° (sagittal plane, lateral). For the computer‐navigated set, the values were 89.7–89.9° (coronal) and 89.1–89.4° (sagittal). Comparison between the conventional and computer‐navigated tibial measurements were not different at the 95% confidence interval (CI) for CT, fluoroscopy or radiographic assessments.

Conclusions

Our results demonstrate that accuracy of TAA tibial preparation using computer‐navigation equals that of the conventional technique performed by a foot and ankle surgeon experienced in TAA. We anticipate that this investigation will encourage the development of computer‐navigation applications specific to TAA, with the potential of improving accuracy over conventional methods. Copyright © 2008 John Wiley & Sons, Ltd.
Cardiac function during steep Trendelenburg position and CO2 pneumoperitoneum for robotic‐assisted prostatectomy: a trans‐oesophageal Doppler probe study
Authors: Falabella Andres , Moore‐Jeffries Earl , Sullivan Michael J. , Nelson Rebecca , Lew Michael
Published: January 2008

Background

Haemodynamic changes associated with pneumoperitoneum and steep Trendelenburg position were investigated in non‐obese, ASA I–II males, using general anaesthesia (sevoflurane in air/O2, 40%) undergoing robotic‐assisted laparoscopic prostatectomy.

Methods

A trans‐oesophageal echo‐Doppler probe (Arrow International) measured cardiovascular changes in heart rate (HR), mean arterial pressure (MAP), cardiac output (CO), systemic vascular resistance (SVR), stroke volume (SV) and aortic diameter (AoD) in 35 of 37 males. Assessments were conducted after induction of general anaesthesia in: the supine position; at 45° Trendelenburg; Trendelenburg + pnuemoperitoneum (intra‐abdominal 15 mmHg); and at the end of surgery in the supine position.

Results

The Trendelenburg position increased stroke volume. Trendelenburg position + pneumoperitoneum increased MAP and SVR and decreased AoD.

Conclusions

Pneumoperitoneum and steep Trendelenburg position significantly increase MAP and SVR. Trendelenburg position increased stroke volume. Pneumoperitoneum decreases aortic diameter. No significant changes in cardiac output or stroke volume were noted. Copyright © 2008 John Wiley & Sons, Ltd.
Numerical evaluation method for catheter prototypes using photo‐elastic stress analysis on patient‐specific vascular model
Authors: Tercero C , Okada Y , Ikeda S , Fukuda T , Sekiyama K , Negoro M , Takahashi I
Published: January 2008

Background

To date, no quantitative analysis has been developed to evaluate catheter performance inside the vascular lumen.

Methods

An evaluation system for endovascular tools was built with a polyurethane elastomer vascular model inside a polariscope and a catheter driving system. This robotic system reproduced a catheter insertion trajectory inside the vascular model, using a surgical catheter and three catheter prototypes used for motion capture on endovascular surgery simulation. Birefringence is produced by photo‐elastic characteristics of the polyurethane elastomer when the material is submitted external stress. The birefringence produced by the catheter on the vascular model wall was recorded and represented numerically by the correlation between consecutive frames of the registered video.

Results

Correlation values between frames showed that the performance of the prototypes was lower than that of the medical use catheter. The performance of prototypes was reduced by microcoils on their tips.

Conclusions

This methodology opens new options to evaluate medical catheters and physicians skills. Copyright © 2008 John Wiley & Sons, Ltd.
Is a black market in telemedicine on the horizon?
Authors: McLean Thomas R , McLean Patrick B
Published: January 2008

Background

Regulation of a global market by regional licensure systems and trade barriers has significant drawbacks.

Methods

Literature review of telemedicine, law and economics.

Results

Today's patients are willing to use out‐of‐pocket dollars to purchase medical care from: (a) foreign physicians in the medical tourism market; and (b) nurse‐practitioners in pharmacy clinics. As telemedicine comes of age, patients are likely to purchase more health care from foreign telemedical ‘pharmacy’ clinics to avoid the costs, and the hassle, of travel. Many of these foreign medicine providers are likely to be unlicensed. This is problematic because experience with Mydoc.com and Usanetrx.com demonstrates that today's patients are relatively unconcerned with the licensure status of telemedicine providers. Accordingly, the elements of a black market in telemedicine may be on the horizon. Strengthening medical licensure laws is unlikely to keep foreign providers out the US health care market forever. Alternatively, one method to minimize the size of a black market in telemedical services would be to allow the market to regulate itself through the creation of a commodities‐type exchange.

Conclusion

Now is the time to open a global dialogue on how to regulate telemedicine. Copyright © 2008 John Wiley & Sons, Ltd.
How should variable selection be performed with multiply imputed data?
Authors: Wood Angela M. , White Ian R. , Royston Patrick
Published: January 2008

Multiple imputation is a popular technique for analysing incomplete data. Given the imputed data and a particular model, Rubin's rules (RR) for estimating parameters and standard errors are well established. However, there are currently no guidelines for variable selection in multiply imputed data sets. The usual practice is to perform variable selection amongst the complete cases, a simple but inefficient and potentially biased procedure. Alternatively, variable selection can be performed by repeated use of RR, which is more computationally demanding. An approximation can be obtained by a simple ‘stacked’ method that combines the multiply imputed data sets into one and uses a weighting scheme to account for the fraction of missing data in each covariate. We compare these and other approaches using simulations based around a trial in community psychiatry. Most methods improve on the naïve complete‐case analysis for variable selection, but importantly the type 1 error is only preserved if selection is based on RR, which is our recommended approach. Copyright © 2008 John Wiley & Sons, Ltd.
Multinomial goodness‐of‐fit tests for logistic regression models
Authors: Fagerland Morten W. , Hosmer David W. , Bofin Anna M.
Published: January 2008

We examine the properties of several tests for goodness‐of‐fit for multinomial logistic regression. One test is based on a strategy of sorting the observations according to the complement of the estimated probability for the reference outcome category and then grouping the subjects into g equal‐sized groups. A g × c contingency table, where c is the number of values of the outcome variable, is constructed. The test statistic, denoted as Cg, is obtained by calculating the Pearson χ2 statistic where the estimated expected frequencies are the sum of the model‐based estimated logistic probabilities. Simulations compare the properties of Cg with those of the ungrouped Pearson χ2 test (X2) and its normalized test (z). The null distribution of Cg is well approximated by the χ2 distribution with (g−2) × (c−1) degrees of freedom. The sampling distribution of X2 is compared with a χ2 distribution with n × (c−1) degrees of freedom but shows erratic behavior. With a few exceptions, the sampling distribution of z adheres reasonably well to the standard normal distribution. Power simulations show that Cg has low power for a sample of 100 observations, but satisfactory power for a sample of 400. The tests are illustrated using data from a study of cytological criteria for the diagnosis of breast tumors. Copyright © 2008 John Wiley & Sons, Ltd.
Influence of psychological stress on physical pain
Authors: Hwang Gul , Kim Sun‐Kyung , Kim Jung‐Ho , Kim Hack‐Ryul , Park Sang‐Hag , Kim Sang‐Hoon
Published: January 2008

The goal of this study was to determine the influence of psychological stress on non‐pathologic physical pain in a general population. Data pertaining to the source of, response to, and coping with stress, as well as site and intensity of pain was collected on 91 non‐patient subjects using a self‐report questionnaire. The questionnaire consisted of a Global Assessment of Recent Stress, Stress Response Inventory and Ways of Coping Checklist, in addition to the Site and Intensity of Stress‐Related Pain. It was found that the degree of stress was proportional to the pain severity. Also, the degree of responses to stress and coping style played a role in pain severity. Moreover, economic status, stress from sickness or injury, and somatization were the best predictors of the pain severity in our study population. The most common stress‐related pain was occipital headache, and the pain sites were dependent on certain stress variables. The high pain group and no pain group showed distinct demographic and stress profiles. The various aspects of psychological stress affect the incidence, site and intensity of physical pain. Copyright © 2008 John Wiley & Sons, Ltd.
Optimized mismatch resolution for COTS selection
Authors: Mohamed Abdallah , Ruhe Guenther , Eberlein Armin
Published: January 2008

The use of Commercial Off‐The‐Shelf (COTS) products in the software development process requires the evaluation of existing COTS products, and then selecting the one that best fits system requirements. In this process, it is inevitable to encounter mismatches between COTS features and system requirements. Mismatches occur as a result of an excess or shortage of COTS capabilities. Many of these mismatches are resolved after selecting a COTS product. Existing COTS‐selection approaches fail to properly consider these mismatches. This article presents MiHOS (Mismatch Handling for COTS Selection), an approach that aims at addressing mismatches while considering limited resources. MiHOS can be integrated with existing COTS‐selection methods at two points: (i)When evaluating COTS candidates in order to estimate the anticipated fitness of the candidates if their mismatches are resolved. This helps to base our COTS‐selection decisions on the fitness that the COTS candidates will eventually have if selected. (ii) After selecting a COTS product in order to plan the resolution of the most appropriate mismatches using suitable actions, such that the most important risk, technical, and resource constraints are met. A case study from the e‐services domain is used to illustrate the method and to discuss its added value. Copyright © 2008 John Wiley & Sons, Ltd.
Strukturen von polaren Magnesiumorganylen: Synthese und Struktur von Basen‐Addukten des Bis(cyclopentadienyl)magnesiums
Authors: Jaenschke Anja , Paap Joachim , Behrens Ulrich
Published: January 2008

Structures of Polar Magnesium Organyls: Synthesis and Structure of Base Adducts of Bis(cyclopentadienyl)magnesium

Eight donor‐acceptor complexes of bis(cyclopentadienyl)magnesium (1) with N‐ and O‐donor Lewis bases have been synthesized and characterized by X‐ray structure analysis. With acetonitrile, dimethoxyethane, diethyleneglycoldimethylether, dioxane, and tetramethylethylenediamine simple 1:1 adducts are formed (2–6). In some cases a change of the hapticity of one cyclopentadienylring from η5 to η2 or η1 is observed (4–6). In the adduct with pentamethyldiethylenetriamine (7) one C5H5‐ring is removed from the magnesium atom forming the cation [Mg(C5H5)(PMDTA)]+ and an uncoordinated five‐ring anion. With the crown ether 15‐crown‐5 the two ionic Mg compounds 8 and 9 are formed which have a [Mg(15‐crown‐5)L2]2+‐cation [L = pyridine, THF] and two uncoordinated cyclopentadienyl anions. Cyclopentadienyl‐methyl‐magnesium reacts with 15‐crown‐5 to the salt [Mg(CH3)(15‐crown‐5)]+ C5H5− (10) which has also a free cyclopentadienyl anion.
A population facing climate change: joint influences of Allee effects and environmental boundary geometry
Authors: Roques Lionel , Roques Alain , Berestycki Henri , Kretzschmar André
Published: January 2008

As a result of climate change, many populations have to modify their range to follow the suitable areas—their “climate envelope”—often risking extinction. During this migration process, they may face absolute boundaries to dispersal because of external environmental factors. Consequently, not only the position, but also the shape of the climate envelope can be modified. We use a reaction‐diffusion model to analyse the effects on population persistence of simultaneous changes in the position and shape of the climate envelope. When the growth term is of logistic type, we show that extinction and persistence are principally conditioned by the species mobility and the speed of climate change, but not by the shape of the climate envelope. However, with a growth term taking an Allee effect into account, we find a high sensitivity to variations in the shape of the climate envelope. In this case, the species which have a high mobility, although they could more easily follow the migration of the climate envelope, would be at risk of extinction when encountering a local narrowing of the boundary geometry. This effect can be attenuated by a progressive opening at the exit of the narrowing into the available space, even though this leads temporarily to a diminished area of the climate envelope.
The Effect of Phospholipids on Milkfat Crystallization Behavior
Authors: Fedotova Yuliya , Lencki Robert W.
Published: January 2008

Depending on the production method, the fat component in butter can either be in a continuous phase or entrapped by milk fat globule membranes (MFGM). Phospholipids like those present in the MFGM are known to affect milk fat crystallization behavior. This study examines the effect of MFGM phospholipid concentration on butter crystal structure. Regular raw cream was first concentrated to 85% fat via centrifugation to produce a “plastic” cream, and was then blended with anhydrous milk fat (AMF) and skim milk in order to maintain the total fat‐to‐water ratio while altering the total amount of MFGM in the butter product. Whereas mixtures of AMF and skim milk contained large spherulites that had finer structures as the degree of supercooling was increased, the addition of globular fat (GF) broke up these structures, eventually producing smaller individual needle‐like crystals. However, high levels of GF also lead to the coalescence of the aqueous phase, creating large water pockets that adversely affect sensory properties. Thus, the phospholipid concentration in the final butter product must be controlled in order to obtain optimal crystal structure and product quality.
Global Perceived Health and Health-Related Quality of Life in Elderly Primary Care Patients with Symptoms of Heart Failure
Authors: Johansson Peter , Broström Anders , Dahlström Ulf , Alehagen Urban
Published: January 2008

Background: The aim was to examine whether a single question about global perceived health (GPH) is associated with the domains of health-related quality of life (HR-QoL) as assessed by the SF-36, and whether the scores in these domains differ from the different scores of the GPH in relation to left ventricular ejection fraction (LVEF).

Method: The study included 412 elderly outpatients with symptoms of heart failure (HF). Echocardiography was used to determine their LVEF, and GPH was assessed by the first question on the SF-36.

Results: The correlations between GPH and the different domains in SF-36 ranged from 0.33 to 0.64 in patients with LVEF ≥ 50% and was between 0.29 and 0.59 in patients with LVEF < 40%. Regression analyses revealed GPH to be the strongest predictor of HR-QoL. Patients with LVEF < 40% rating poor GPH differed significantly ( p < 0.05) from those with good or moderate GPH in six of the eight HR-QoL domains.

Conclusion: One question about GPH gives a good general description of HR-QoL and may therefore be used as a simple tool to assess HR-QoL in elderly outpatients with clinical symptoms of HF.
Reciprocal regulation of the human sterol regulatory element binding protein (SREBP)‐1a promoter by Sp1 and EGR‐1 transcription factors
Authors: Fernández-Álvarez Ana , Tur Gemma , López-Rodas Gerardo , Casado Marta
Published: January 2008

Sterol regulatory element binding protein (SREBP)‐1a is a transcription factor that is highly expressed in actively growing cells, and is involved in the biosynthesis of cholesterol, fatty acids and phospholipids. We have mapped the minimal human SREBP‐1a promoter region to 75 bp upstream of the translation start site where we discovered a functional role for the 3 GC‐boxes containing overlapping sites for the Sp1 and EGR‐1 transcription factors. Intact SP1‐binding sites are essential for promoter activity, whereas EGR‐1 suppresses the transcription of the human SREBP‐1a promoter. These results reveal a novel physiologically relevant transcriptional mechanism for the reciprocal regulation of the SREBP‐1a expression.
A family of eukaryotic lysophospholipid acyltransferases with broad specificity
Authors: Ståhl Ulf , Stålberg Kjell , Stymne Sten , Ronne Hans
Published: January 2008

The budding yeast ALE1 gene encodes a lysophospholipid acyltransferase (LPLAT) with broad specificity. We show that yeast LPLAT (ScLPLAT) belongs to a distinct protein family that includes human MBOAT1, MBOAT2, MBOAT4, and several closely related proteins from other eukaryotes. We further show that two plant proteins within this family, the Arabidopsis proteins AtLPLAT1 and AtLPLAT2, possess lysophospholipid acyltransferase activities similar to ScLPLAT. We propose that other members of this protein family, which we refer to as the LPLAT family, also are likely to possess LPLAT activity. Finally, we show that ScLPLAT differs from the specific lysophosphatidic acid acyltransferase that is encoded by SLC1 in that it cannot efficiently use lysophosphatidic acid produced by acylation of glycerol‐3‐phosphate in vitro.
High affinity selenium uptake in a keratinocyte model
Authors: Ganyc Dennis , Self William T.
Published: January 2008

The distribution of selenium in mammals has been recently shown to be mediated primarily by selenoprotein P. Even in the absence of selenoprotein P, selenium is distributed from the liver into all organs and tissues when supplemented in the diet. The form of selenium that is actively taken up by mammalian cells at trace concentrations has yet to be determined. We used a human keratinocyte model to determine whether reduction of the oxyanion selenite to the more reduced form of selenide (HSe−) would affect uptake. Indeed a reduced form of selenium, presumably selenide, was actively transported into keratinocytes and displayed saturation kinetics with an apparent K
m of 279 nM. ATPase inhibitors blocked the uptake of selenide, as did the competing anions molybdate and chromate, but not sulfate. These results suggest that the small molecule form of selenium that is distributed in tissues is hydrogen selenide, despite its sensitivity to oxygen and reactivity to thiols.
Adiponectin inhibits induction of TNF‐α/RANKL‐stimulated NFATc1 via the AMPK signaling
Authors: Yamaguchi Noboru , Kukita Toshio , Li Yin-Ji , Kamio Noriaki , Fukumoto Satoshi , Nonaka Kazuaki , Ninomiya Yuzo , Hanazawa Shigemasa , Yamashita Yoshihisa
Published: January 2008

We investigated here whether adiponectin can exhibit an inhibitory effect on tumor necrosis factor‐alpha (TNF‐α)‐ and receptor activator of nuclear factor‐κB ligand (RANKL)‐induced osteoclastogenesis by using RAW264 cell D clone with a high efficiency to form osteoclasts. Globular adiponectin (gAd) strongly inhibited TNF‐α/RANKL‐induced differentiation of osteoclasts by interfering with TNF receptor‐associated factor 6 production and calcium signaling; consequently, the induction of nuclear factor of activated T cells c1 (NFATc1) was strongly inhibited. Moreover, we observed that inhibition of AMP‐activated protein kinase abrogated gAd inhibition for TNF‐α/RANKL‐induced NFATc1 expression. Our data suggest that adiponectin acts as a potent regulator of bone resorption observed in diseases associated with cytokine activation.
Origin and evolution of the c.844_845ins68/c.833T>C mutations within the cystathionine β‐synthase gene in great apes
Authors: Romano Maurizio , Bacalini Maria Giulia , Verschoor Ernst J. , Crovella Sergio , Baralle Francisco E.
Published: January 2008

The c.[833C; 844_845ins68] is a common haplotype of the human cystathionine β‐synthase gene among healthy individuals. This polymorphism (5–40% allelic frequency in different populations) consists of the c.844_845ins68 insertion that segregates in cis with the pathogenic c.833T>C substitution (p.I278T). Through genotyping of primates, we have found that gorillas, chimpanzees and bonobos are homozygous for the 68 bp insertion, c.844_845ins68. In gorillas and bonobos, the c.844_845ins68 lesion segregates in cis with the wild‐type c.833T variant, whilst chimpanzees present the human haplotype. These genetic evidences suggest that the origin of the 68 bp insertion might be dated back to 6–8 million years ago, and that the c.833T>C substitution occurred within the allele carrying the insertion. The evolutionary conservation of this peculiar haplotype supports the hypothesis of its protective effects against cardiovascular diseases.