bluuebunny/crossref_metadata_2025 huggingface dataset:
Time trends in incidence of myocardial infarction in male and female dominated occupations in Stockholm, Sweden
Authors: Östlin Piroska , Klerdal Kristina , Hammar Niklas
Published: July 2008

Aims: To investigate time trends in first acute myocardial infarction (MI) incidence in male and female dominated occupations in Stockholm during 1977—1996. Methods: Population-based case-control study, where all first events of acute MI among participants aged 40—69 in Stockholm 1977—1996 were identified, using registers of hospital discharges and deaths. Controls were selected randomly using national population registers. There were 16,531 male and 4382 female cases and 117,015 male and 102,083 female controls. In all, 222 female cases worked in male dominated occupations and 844 male cases worked in female dominated occupations. Results: Both women and men in male dominated occupations showed an elevated relative risk of first MI compared to other employees during the study period. Between 1985—1996, when there was a general decline in MI incidence in Sweden, women in male dominated occupations tended to show an increasing trend. Women in female dominated high and intermediate occupations had a lower relative risk of MI compared to other women in the same socioeconomic group. In male dominated and non-manual female dominated occupations a decline in the incidence of MI was seen during 1985—1996 in men but not in women. Conclusions: Work in male dominated occupations appears to be associated with an increased risk of MI in both genders. There is a need to investigate possible work related or other factors that may be driving this elevated risk.
Reassessing the Fear of Crime
Authors: Gray Emily , Jackson Jonathan , Farrall Stephen
Published: July 2008

A large body of empirical research exploring emotional responses to crime in Europe, North America and elsewhere suggests that substantial proportions of the public worry about victimization. The British Crime Survey (BCS) has asked questions exploring English and Welsh respondents' worry about crime since 1982, and in the 2003—4 sweep of the BCS new questions were inserted into a subsection to explore the frequency and intensity of such fearful events. As well as illustrating the rationale of the new measurement strategy, this research note reports the results of the new questions in direct relation to the `old' methods. The findings show that few people experience specific events of worry on a frequent basis and that `old'-style questions magnify the everyday experience of fear. We propose that `worry about crime' is often best seen as a diffuse anxiety about risk rather than any pattern of everyday concerns over personal safety.
Appetite-Related Gut Peptides in Obesity and Binge Eating Disorder
Authors: Geliebter Allan , Ochner Christopher N. , Aviram-Friedman Roni
Published: July 2008

The worldwide increase in obesity prevalence is a result of positive energy balance, with energy intake exceeding expenditure. The eating behavior in obesity ranges from mild passive overconsumption to excessive overeating with loss of control observed in binge eating disorder (BED). The signaling systems that underlie appetite control in BED are complex and, at this point, not well understood. The present review highlights the current knowledge of key components of the gut peptide system and examines evidence of defects in signaling that differentiate obese binge eaters from obese non—binge eaters. The signaling network underlying hunger, satiety, and metabolic status includes leptin and insulin from energy stores and cholecystokinin, glucagon-like peptide-1, peptide YY(3-36), and ghrelin from the gastrointestinal tract. Of the many gastrointestinal peptides, ghrelin is the only established appetite-stimulating one, whereas cholecystokinin, glucagon-like peptide-1, and peptide YY(3-36) promote satiety. Adipose tissue provides hormonal signals via leptin and insulin to the brain about energy stores and likely from adiponectin and resistin. Binge eating has been related to a dysfunction in the ghrelin signaling system. Moreover, the larger gastric capacity observed in BED may further reduce satiety signals and contribute to overeating.
A computational investigation of cation ordering phenomena in the binary
spinel system MgAl2O4-FeAl2O4
Authors: Palin E. J. , Harrison R. J.
Published: July 2008

The systematics of cation ordering in binary spinel solid solutions have been
investigated using an interatomic potential model combined with Monte Carlo
simulations. The formalism to describe a system containing three cation species
ordering over two non-equivalent sub-lattices is developed and the method applied
to the
MgAl2O4-FeAl2O4
binary solid solution. Our results compare favourably with experimental
measurements of site-occupancy data, although the experiments display a slightly
larger degree of non-ideality than the simulations. A possible kinetic origin of
the non-ideal behaviour was examined by performing simulations in which only
exchange of Mg and Fe2+ between tetrahedral and octahedral
sites was permitted below the Al-blocking temperature of 1160 K. This approach
improves the agreement with the experimental site occupancies, and suggests that
the blocking temperature for moving Mg and Fe2+ between
tetrahedral and octahedral sites is significantly lower than for moving
Al
Structural role of copper in the minerals of the pearceite-polybasite group:
the case of the new minerals cupropearceite and cupropolybasite
Authors: Bindi L. , Evain M. , Spry P. G. , Tait K. T. , Menchetti S.
Published: July 2008

The pearceite-polybasite group of minerals, general formula
[M6T2S7][Ag9CuS4]
with M = Ag, Cu; and T = As, Sb, show a crystal structure which can be described
as the succession, along the c axis, of two pseudo-layer modules: a
[M6T2S7]2–A
module layer and a
[Ag9CuS4]2+B
module layer. Copper is present in one structural position of the
B module layer and replaces Ag in the only fully
occupied M position of the A module layer. When the Cu
content is >4.00 a.p.f.u., the structural position of the
A module layer becomes Cu-dominant and,
consequently, the mineral deserves its own name. In this paper we report the
crystal-chemical characterization of two Cu-rich members exhibiting the 111
unitcell type (corresponding to the Tac polytype). One sample (space group
(P)m1,
a 7.3218(8), c
11.8877(13) Å, V 551.90(10) Å3, Z
= 1) having As >Sb and with the structural position of the
A module layer dominated by Cu, has been named
cupropearceite and the other sample (space group (P3̄)m1, a 7.3277(3), c
11.7752(6) Å, V 547.56(8) Å3, Z =
1) having Sb >As has been named cupropolybasite.

Both the new minerals and mineral names have been approved by the
IMA-CNMNC.
Crystal chemistry of leucite from the Roman Comagmatic Province (central
Italy): a multi-methodological study
Authors: Gatta G. D. , Rotiroti N. , Bellatreccia F. , Della Ventura G.
Published: July 2008

A multi-methodological study, based on electron microprobe analysis (in
wavelength dispersive mode), single-crystal X-ray diffraction (XRD), transmission
electron microscopy and single-crystal Fourier transform infrared spectroscopy was
performed in order to describe the crystal chemistry of four leucite samples from
different localities of the Roman Comagmatic Province (central Italy). All the
crystals examined were found to be tetragonal (space group
I41/a with a = 13.076–13.103 Å
and c = 13.744–13.784 Å) and characterized by a complex twinning (merohedric
twins: on the tetragonal planes (110) and (1̄10) with the two individuals having
parallel crystallographic axes with a and b interchanged; pseudo-merohedric twins:
on the tetragonal planes (101), (011), (1̄01), (01̄ 1), with the two individuals
having parallel a (or b) axes and the remaining two axes not parallel). The
chemical analyses show that all the samples contain minor Na and Fe. Infrared
spectroscopy shows that all samples contain structurally bound water molecules, up
to unexpectedly large amounts (~0.4 wt.%) for a nominally anhydrous mineral,
suggesting that ‘analcime-like’ substitution (K to Na + H2O)
occurs in the leucite samples investigated here. The detection limits of the
‘analcime-like’ substitution by singlecrystal XRD are also discussed.
Function2Gene: A gene selection tool to increase the power of genetic association studies by utilizing public databases and expert knowledge
Authors: Armstrong Don L , Jacob Chaim O , Zidovetzki Raphael
Published: July 2008

Background

Many common disorders have multiple genetic components which convey increased susceptibility. SNPs have been used to identify genetic components which are associated with a disease. Unfortunately, many studies using these methods suffer from low reproducibility due to lack of power.

Results

We present a set of programs which implement a novel method for searching for disease-associated genes using prior information to select and order genes from publicly available databases by their prior likelihood of association with the disease. These programs were used in a published study of childhood-onset SLE which yielded novel associations with modest sample size.

Conclusion

Using prior information to decrease the size of the problem space to an amount commensurate with available samples and resources while maintaining appropriate power enables researchers to increase their likelihood of discovering reproducible associations.
Topology of evolving, mutagenized viral populations: quasispecies expansion, compression, and operation of negative selection
Authors: Ojosnegros Samuel , Agudo Rubén , Sierra Macarena , Briones Carlos , Sierra Saleta , González- López Claudia , Domingo Esteban , Cristina Juan
Published: July 2008

Background

The molecular events and evolutionary forces underlying lethal mutagenesis of virus (or virus extinction through an excess of mutations) are not well understood. Here we apply for the first time phylogenetic methods and Partition Analysis of Quasispecies (PAQ) to monitor genetic distances and intra-population structures of mutant spectra of foot-and-mouth disease virus (FMDV) quasispecies subjected to mutagenesis by base and nucleoside analogues.

Results

Phylogenetic and PAQ analyses have revealed a highly dynamic variation of intrapopulation diversity of FMDV quasispecies. The population diversity first suffers striking expansions in the presence of mutagens and then compressions either when the presence of the mutagenic analogue was discontinued or when a mutation that decreased sensitivity to a mutagen was selected. The pattern of mutations found in the populations was in agreement with the behavior of the corresponding nucleotide analogues with FMDV in vitro. Mutations accumulated at preferred genomic sites, and dn/ds ratios indicate the operation of negative (or purifying) selection in populations subjected to mutagenesis. No evidence of unusually elevated genetic distances has been obtained for FMDV populations approaching extinction.

Conclusion

Phylogenetic and PAQ analysis provide adequate procedures to describe the evolution of viral sequences subjected to lethal mutagenesis. These methods define the changes of intra-population structure more precisely than mutation frequencies and Shannon entropies. PAQ is very sensitive to variations of intrapopulation genetic distances. Strong negative (or purifying) selection operates in FMDV populations subjected to enhanced mutagenesis. The quantifications provide evidence that extinction does not imply unusual increases of intrapopulation complexity, in support of the lethal defection model of virus extinction.
RAS gene polymorphisms, classical risk factors and the advent of coronary artery disease in the Portuguese population
Authors: Freitas Ana I , Mendonça Isabel , Brión Maria , Sequeira Miguel M , Reis Roberto P , Carracedo Angel , Brehm António
Published: July 2008

Background

Several polymorphisms within the renin-angiotensin system cluster of genes have been associated with the advent of coronary artery disease (CAD) or related pathologies. We investigated the distribution of 5 of these polymorphisms in order to find any association with CAD development and distinguish if any of the biochemical and behavioural factors interact with genetic polymorphisms in the advent of the disease.

Methods

ACE I/D (rs4340), ACE A11860G (rs4343), AT1R A1166C (rs5186), AGT T174M (rs4762) and AGT M235T (rs699) gene polymorphisms were PCR-RFLP analysed in 298 CAD patients and 510 controls from Portugal. Several biochemical and behavioural markers were obtained.

Results

ACE I/D DD and ACE11860 GG genotypes are risk factors for CAD in this population. The simultaneous presence of ACE I/D I and ACE11860 A alleles corresponds to a significant trend towards a decrease in CAD incidence. We found several synergistic effects between the studied polymorphisms and classical risk factors such as hypertension, obesity, diabetes and dyslipidaemia: the presence of the DD genotype of ACE I/D (and also ACE11860 GG) increases the odds of developing CAD when associated to each one of these classical risk factors, particularly when considering the male and early onset CAD subgroup analysis; AGT235 TT also increases the CAD risk in the presence of hypertension and dyslipidaemia, and AT1R1166 interacts positively with hypertension, smoking and obesity.

Conclusion

ACE polymorphisms were shown to play a major role in individual susceptibility to develop CAD. There is also a clear interaction between RAS predisposing genes and some biochemical/environmental risk factors in CAD onset, demonstrating a significant enhancement of classical markers particularly by ACE I/D and ACE11860.
Dinucleotide repeat polymorphism in Fms-like tyrosine kinase-1 (Flt-1) gene is not associated with preeclampsia
Authors: Kim Shin-Young , Lim Ji-Hyae , Yang Jae-Hyug , Kim Moon-Young , Han Jung-Yeol , Ahn Hyun-Kyong , Choi Jun-Seek , Park So-Yeon , Kim Mi-Jin , Ryu Hyun-Mee
Published: July 2008

Background

Preeclampsia is a major cause of maternal and perinatal mortality and morbidity. The etiology of preeclampsia remains unclear. Recently, it was shown that misregulation of fms-like tyrosine kinase-1 (Flt-1) in the peripheral blood mononuclear cells of pregnant women results in over-expression of the soluble splice variant of Flt-1, sFlt-1, producing an additional (extra-placental) source of sFlt-1 that can contribute to the etiology of preeclampsia. The aim of this study was to investigate the relationship between preeclampsia and a dinucleotide (threonine-glycine; TG)n repeat polymorphism in the 3' non-coding region of the Flt-1 gene.

Methods

The number of the d(TG)n repeats was analyzed in 170 patients with preeclampsia and in 202 normotensive pregnancies. The region containing the dinucleotide repeat polymorphism of the Flt-1 gene was amplified by polymerase chain reaction (PCR) from the DNA samples and was analyzed by direct PCR sequencing.

Results

We found 10 alleles of the dinucleotide repeat polymorphism and designated these as allele*12 (A1) through allele*23 (A12) according to the number of the TG repeats, from 12 to 23. The frequency of the 14-repeat allele (A3) was most abundant (63.82% in preeclampsia and 69.06% in controls), followed by the 21-repeat allele (A10; 28.53% in preeclampsia and 23.76% in controls). There was no significant difference in the allele frequency between patients with preeclampsia and normal controls. The most common genotype in preeclamptic and normotensive pregnancies was heterozygous (TG)14/(TG)21 (41.76%) and homozygous (TG)14/(TG)14 (45.05%), respectively. However, the genotype frequencies were not significantly different between preeclamptic patients and controls.

Conclusion

This is the first study to characterize the dinucleotide repeat polymorphism of the Flt-1 gene in patients with preeclampsia. We found no differences in the allele or genotype frequencies between patients with preeclampsia and normal pregnancies. Although limited by a relatively small sample size, our study suggests that the d(TG)n repeat polymorphism of the Flt-1 gene is not associated with the development of preeclampsia in Korean pregnant women.
Systematic analysis of the effect of multiple templates on the accuracy of comparative models of protein structure
Authors: Chakravarty Suvobrata , Godbole Sucheta , Zhang Bing , Berger Seth , Sanchez Roberto
Published: July 2008

Background

Although multiple templates are frequently used in comparative modeling, the effect of inclusion of additional template(s) on model accuracy (when compared to that of corresponding single-template based models) is not clear. To address this, we systematically analyze two-template models, the simplest case of multiple-template modeling. For an existing target-template pair (single-template modeling), a two-template based model of the target sequence is constructed by including an additional template without changing the original alignment to measure the effect of the second template on model accuracy.

Results

Even though in a large number of cases a two-template model showed higher accuracy than the corresponding one-template model, over the entire dataset only a marginal improvement was observed on average, as there were many cases where no change or the reverse change was observed. The increase in accuracy due to the structural complementarity of the templates increases at higher alignment accuracies. The combination of templates showing the highest potential for improvement is that where both templates share similar and low (less than 30%) sequence identity with the target, as well as low sequence identity with each other. The structural similarity between the templates also helps in identifying template combinations having a higher chance of resulting in an improved model.

Conclusion

Inclusion of additional template(s) does not necessarily improve model quality, but there are distinct combinations of the two templates, which can be selected a priori, that tend to show improvement in model quality over the single template model. The benefit derived from the structural complementarity is dependent on the accuracy of the modeling alignment. The study helps to explain the observation that a careful selection of templates together with an accurate target:template alignment are necessary to the benefit from using multiple templates in comparative modeling and provides guidelines to maximize the benefit from using multiple templates. This enables formulation of simple template selection rules to rank targets of a protein family in the context of structural genomics.
Fractal parameters and vascular networks: facts & artifacts
Authors: Mancardi Daniele , Varetto Gianfranco , Bucci Enrico , Maniero Fabrizio , Guiot Caterina
Published: July 2008

Background

Several fractal and non-fractal parameters have been considered for the quantitative assessment of the vascular architecture, using a variety of test specimens and of computational tools. The fractal parameters have the advantage of being scale invariant, i.e. to be independent of the magnification and resolution of the images to be investigated, making easier the comparison among different setups and experiments.

Results

The success of several commercial and/or free codes in computing the fractal parameters has been tested on well known exact models. Based on such a preliminary study, we selected the code Frac-lac in order to analyze images obtained by visualizing the angiogenetic process occurring in chick Chorio Allontoic Membranes (CAM), assumed to be paradigmatic of a realistic 2D vascular network. Among the parameters investigated, the fractal dimension Df proved to be the most robust estimator for CAM vascular networks. Moreover, only Df was able to discriminate between effective and elusive increases in vascularization after drug-induced angiogenic stimulations on CAMs.

Conclusion

The fractal dimension Df is likely to be the most promising tool for monitoring the effectiveness of anti-angiogenic therapies in various clinical contexts.
CD45 immunoaffinity depletion of vesicles from Jurkat T cells demonstrates that exosomes contain CD45: no evidence for a distinct exosome/HIV-1 budding pathway
Authors: Coren Lori V , Shatzer Teresa , Ott David E
Published: July 2008

The presence of relatively high levels of cellular protein contamination in density-purified virion preparations is a confounding factor in biochemical analyses of HIV and SIV produced from hematopoietic cells. A major source of this contamination is from vesicles, either microvesicles or exosomes, that have similar physical properties as virions. Thus, these particles can not be removed by size or density fractionation. Although virions and vesicles have similar cellular protein compositions, CD45 is excluded from HIV-1 yet is present in vesicles produced from hematopoietic cells. By exploiting this finding, we have developed a CD45 immunoaffinity depletion procedure that removes vesicles from HIV-1 preparations. While this approach has been successfully applied to virion preparations from several different cell types, some groups have concluded that "exosomes" from certain T cell lines, specifically Jurkat, do not contain CD45. If this interpretation is correct, then these vesicles could not be removed by CD45 immunoaffinity depletion. Here we show that dense vesicles produced by Jurkat and SupT1/CCR5 cells contain CD45 and are efficiently removed from preparations by CD45-immunoaffinity depletion. Also, contaminating cellular proteins were removed from virion preparations produced by these lines. Previously, the absence of CD45 from both "exosomes" and virions has been used to support the so called Trojan exosome hypothesis, namely that HIV-1 is simply an exosome containing viral material. The presence of CD45 on vesicles, including exosomes, and its absence on virions argues against a specialized budding pathway that is shared by both exosomes and HIV-1.
Genes responsive to both oxidant stress and loss of estrogen receptor function identify a poor prognosis group of estrogen receptor positive primary breast cancers
Authors: Yau Christina , Benz Christopher C
Published: July 2008

Introduction

Oxidative stress can modify estrogen receptor (ER) structure and function, including induction of progesterone receptor (PR), altering the biology and clinical behavior of endocrine responsive (ER-positive) breast cancer.

Methods

To investigate the impact of oxidative stress on estrogen/ER-regulated gene expression, RNA was extracted from ER-positive/PR-positive MCF7 breast cancer cells after 72 hours of estrogen deprivation, small-interfering RNA knockdown of ER-α, short-term (8 hours) exposure to various oxidant stresses (diamide, hydrogen peroxide, and menadione), or simultaneous ER-α knockdown and oxidant stress. RNA samples were analyzed by high-throughput expression microarray (Affymetrix), and significance analysis of microarrays was used to define gene signatures responsive to estrogen/ER regulation and oxidative stress. To explore the association of these signatures with breast cancer biology, microarray data were analyzed from 394 ER-positive primary human breast cancers pooled from three independent studies. In particular, an oxidant-sensitive estrogen/ER-responsive gene signature (Ox-E/ER) was correlated with breast cancer clinical parameters and disease-specific patient survival (DSS).

Results

From 891 estrogen/ER-regulated probes, a core set of 75 probes (62 unique genes) responsive to all three oxidants were selected (Ox-E/ER signature). Ingenuity pathway analysis of this signature highlighted networks involved in development, cancer, and cell motility, with intersecting nodes at growth factors (platelet-derived growth factor-BB, transforming growth factor-β), a proinflammatory cytokine (tumor necrosis factor), and matrix metalloproteinase-2. Evaluation of the 394 ER-positive primary breast cancers demonstrated that Ox-E/ER index values correlated negatively with PR mRNA levels (rp = -0.2; P = 0.00011) and positively with tumor grade (rp = 0.2; P = 9.741 × e-5), and were significantly higher in ER-positive/PR-negative versus ER-positive/PR-positive breast cancers (t-test, P = 0.0008). Regardless of PR status, the Ox-E/ER index associated with reduced DSS (n = 201; univariate Cox, P = 0.078) and, using the optimized cut-point, separated ER-positive cases into two significantly different DSS groups (log rank, P = 0.0009).

Conclusion

An oxidant-sensitive subset of estrogen/ER-responsive breast cancer genes linked to cell growth and invasion pathways was identified and associated with loss of PR and earlier disease-specific mortality, suggesting that oxidative stress contributes to the development of an aggressive subset of primary ER-positive breast cancers.
Impact of Immediate Versus Delayed Axillary Node Dissection on Surgical Outcomes in Breast Cancer Patients With Positive Sentinel Nodes: Results From American College of Surgeons Oncology Group Trials Z0010 and Z0011
Authors: Olson John A. , McCall Linda M. , Beitsch Peter , Whitworth Pat W. , Reintgen Douglas S. , Blumencranz Peter W. , Leitch A. Marilyn , Saha Sukamal , Hunt Kelly K. , Giuliano Armando E.
Published: July 2008

Purpose

Patients with breast cancer metastasis to the sentinel lymph nodes (SLNs) generally undergo completion axillary lymph node dissection (cALND), either concurrently with SLN biopsy or at a second procedure. The impact of the timing of cALND on pathologic results and complications in these patients has not been examined.

Patients and Methods

We examined outcomes from SLN-positive patients in American College of Surgeons Oncology Group (ACOSOG) trials Z0010 and Z0011. Pathologic data examined included primary tumor characteristics, total number of SLNs recovered, positive SLN(s) and non-SLN(s) identified. Complications assessed included axillary seroma, paresthesia, arm morbidity and range of motion, and lymphedema.

Results

A total of 1,003 assessable patients with SLN metastasis had immediate (n = 425) or delayed (n = 578) cALND. The median number of SLNs and axillary LNs removed were the same between groups. Patients who had immediate cALND more often had larger tumors, SLN metastasis identified intraoperatively, two or more positive SLNs, and higher pathologic N stage. Axillary paresthesia, seroma, and impaired extremity range of motion were more common in the immediate group during the early postoperative period, but not at later time points. There was no difference in lymphedema at any time point.

Conclusion

In ACOSOG trials Z0010 and Z0011, LN recovery and long-term complications were similar after either delayed or immediate cALND for patients with metastasis to SLNs. Patients who undergo immediate cALND experience more short-term morbidity. With respect to staging and complications, there is no clear detriment for patients with a positive SLN who undergo a second procedure for cALND.
Preoperative Gemcitabine and Cisplatin Followed by Gemcitabine-Based Chemoradiation for Resectable Adenocarcinoma of the Pancreatic Head
Authors: Varadhachary Gauri R. , Wolff Robert A. , Crane Christopher H. , Sun Charlotte C. , Lee Jeffrey E. , Pisters Peter W.T. , Vauthey Jean-Nicolas , Abdalla Eddie , Wang Huamin , Staerkel Gregg A. , Lee Jeffrey H. , Ross William A. , Tamm Eric P. , Bhosale Priya R. , Krishnan Sunil , Das Prajnan , Ho Linus , Xiong Henry , Abbruzzese James L. , Evans Douglas B.
Published: July 2008

Purpose

We conducted a phase II trial of preoperative gemcitabine and cisplatin chemotherapy in addition to chemoradiation (Gem-Cis-XRT) and pancreaticoduodenectomy (PD) for patients with stage I/II pancreatic adenocarcinoma.

Patients and Methods

Chemotherapy consisted of gemcitabine (750 mg/m2) and cisplatin (30 mg/m2) given every 2 weeks for four doses. Chemoradiation consisted of four weekly infusions of gemcitabine (400 mg/m2) combined with radiation therapy (30 Gy in 10 fractions administered over 2 weeks) delivered 5 days per week. Patients underwent restaging 4 to 6 weeks after completion of chemoradiation and, in the absence of disease progression, were taken to surgery.

Results

The study enrolled 90 patients; 79 patients (88%) completed chemo-chemoradiation. Sixty-two (78%) of 79 patients were taken to surgery and 52 (66%) of 79 underwent PD. The median overall survival of all 90 patients was 17.4 months. Median survival for the 79 patients who completed chemo-chemoradiation was 18.7 months, with a median survival of 31 months for the 52 patients who underwent PD and 10.5 months for the 27 patients who did not undergo surgical resection of their primary tumor (P < .001).

Conclusion

Preoperative Gem-Cis-XRT did not improve survival beyond that achieved with preoperative gemcitabine-based chemoradiation (Gem-XRT) alone. The longer preoperative interval required more durable biliary decompression (metal stents) but was not associated with local tumor progression. The gemcitabine-based chemoradiation platform is a reasonable foundation on which to build future phase II multimodality trials for stage I/II pancreatic cancer incorporating emerging systemic therapies.
Adjuvant Radiotherapy and Chemotherapy for Pancreatic Carcinoma: The Mayo Clinic Experience (1975-2005)
Authors: Corsini Michele M. , Miller Robert C. , Haddock Michael G. , Donohue John H. , Farnell Michael B. , Nagorney David M. , Jatoi Aminah , McWilliams Robert R. , Kim George P. , Bhatia Sumita , Iott Matthew J. , Gunderson Leonard L.
Published: July 2008

Purpose

To determine prognostic factors and impact of adjuvant chemotherapy (CT) and radiotherapy (RT) on overall survival (OS) after resection of pancreatic adenocarcinoma.

Patients and Methods

We performed a retrospective review 472 consecutive patients who underwent complete resection with negative margins (R0) for invasive carcinoma (T1-3N0-1M0) of the pancreas between 1975 and 2005 at the Mayo Clinic in Rochester, MN. Exclusion criteria included metastatic or unresectable disease at surgery, positive surgical margins, and indolent tumor types (islet cell tumors and mucinous cystadenocarcinoma). Median RT dose was 50.4 Gy in 28 fractions; 98% of RT patients also received concurrent fluorouracil-based CT.

Results

Six patients died within 30 days of surgery. For the 466 surviving patients, median follow-up was 32.4 months; median OS was 21.6 months. Median OS after adjuvant CT-RT was 25.2 versus 19.2 months after no adjuvant therapy (P = .001). Two-year OS was 50% versus 39%, and 5-year OS was 28% versus 17%. Adverse prognostic factors identified by univariate and multivariate analysis included positive lymph nodes (risk ratio [RR] = 1.3; P < .001), high histologic grade (RR = 1.2; P < .001), and no adjuvant therapy (RR = 1.3; P < .001). Tumor extension beyond the pancreas was an adverse prognostic factor by univariate analysis alone (P = .03). Patients receiving adjuvant therapy had more adverse prognostic factors than those not receiving adjuvant therapy (P = .001).

Conclusion

This study represents one of the largest, single-institution, retrospective reviews of adjuvant therapy in patients after R0 resection of carcinoma of the pancreas. Overall survival was better in patients who received adjuvant CT-RT.
Principles of Safe Practice Using an Oncology EHR System for Chemotherapy Ordering, Preparation, and Administration, Part 1 of 2
Authors: Shulman Lawrence N. , Miller Robert S. , Ambinder Edward P. , Yu Peter Paul , Cox John V.
Published: July 2008

An outline of broad principles that should be considered when integrating an electronic health record, and in particular, a chemotherapy ordering module, into practice.
Thermomechanical similarity between Van Aken plasticine and metals in hot-forming processes
Authors: Eckerson K , Liechty B , Sorensen C D
Published: July 2008

In this study, compression tests are conducted to determine the strain, strain rate, and temperature sensitivities of Van Aken plasticine at elevated temperatures. A true stress—true strain relationship is presented in the form of the Norton—Hoff viscoplastic model. The plasticine is most sensitive to the deformation rate and temperature. At low strains, the material hardens with increasing strain, but strain hardening is negligible above a logarithmic strain of approximately 30 per cent. The shear friction factor for a plasticine—metal interface with and without lubrication is estimated using ring compression tests. Without lubrication, the shear friction factor approaches 1.0; however, lubrication with Vaseline considerably reduces friction. In addition to the mechanical properties of the plasticine, thermal conductivity and specific heat capacity are measured. The thermal conductivity is independent of temperature, and the heat capacity varies only slightly with temperature. A discussion on plasticine and metal similarity is presented in detail. It is shown that mechanical similarity is possible between the Van Aken plasticine and many steel and aluminium alloys. For thermal similarity in a hot-deformation process, the product of the Prandtl and the Eckert numbers, the Peclet number, and the thermal boundary conditions must all be matched. Thermal similarity is extremely difficult to achieve exactly; however, it might be possible to satisfy approximately such that the physical model is valid qualitatively.
Simulating optical strain measurement and designing a nanoscale rosette
Authors: Tjhung T , Li K
Published: July 2008

The laser-based interferometric strain—slope rosette (ISSR) has been used to measure principal strains and stresses on material surfaces. In this paper, optical theory models and computer programs are developed to simulate the optical diffraction and interference of the ISSR. The simulation results compare with the experimental results. Then the feasibility of extending the ISSR into a nanoscale rosette is studied. The indentation size is selected on a nanometre scale and other parameters in the nanoscale ISSR design are studied. A virtual optical experiment is conducted to use the designed nanoscale ISSR to measure virtual strains. The simulations show that the ISSR can be potentially extended to nanometre-scale measurement of material deformations.
A simplified non-linear kinematic hardening model for ratchetting and wear assessment in rolling contact
Authors: Mazzù A
Published: July 2008

A model for plasticity assessment in rolling contact is introduced, aimed at simulating the effect of the application of thousands of load cycles in a reasonable time. It is based on the non-linear kinematic and isotropic hardening model of Lemaitre and Chaboche in a simplified formulation suitable for contact problems and allows the calculation of accumulated plastic strain under the contact surface. Wear is introduced as an independent phenomenon, interacting with the plasticization process by removing material layers from the surface and modifying during the load process the stresses which each point is subjected to. The typical material responses to cyclic loading (elastic shakedown, plastic shakedown, and ratchetting) can be obtained by application of the present method; moreover, the effect of wear in stabilizing the strain field for a large number of cycles is shown. The model is validated through comparison with results obtained by other methods and by experiments.
Mode and design sensitivity analyses for brake judder reduction
Authors: Hwang I-J , Park G-J
Published: July 2008

Brake judder is a phenomenon that occurs when the steering wheel vibrates abnormally owing to braking at a high speed. It is classified into cold and hot judders. The former is generated because of an initial uneven disc surface and the latter results from uneven heat spots on the disc surface by braking repeatedly. There are two ways to reduce the judder. One is to reduce the excitation by modification of the disc shapes and pad ingredients. The other is to improve modal characteristics of the suspension system. The latter approach is used in this research. Real vehicle tests and computer simulation are utilized to analyse systematically the judder phenomenon of the vehicle. The Macpherson strut suspension is employed, and the judder sensitivity is calculated on the basis of a design sensitivity analysis. The bush stiffness is reworked and a braking test is carried out to verify the sensitivity result. Judder reduction by the mode control is verified.
Neural modelling of friction material cold performance
Authors: Aleksendrić D , Duboka Č , Mariotti G V
Published: July 2008

The complex and highly non-linear phenomena involved during braking are primarily caused by friction materials’ characteristics. The final friction materials' characteristics are determined by their compositions, manufacturing, and the brake's operating conditions. Analytical models of friction materials' behaviour are difficult, even impossible, to obtain for the case of different brakes' operating conditions. That is why, in this paper, all relevant influences on the friction materials' cold performance have been integrated by means of artificial neural networks. The influences of 26 input parameters, defined by the friction materials' composition (18 ingredients), manufacturing (five parameters), and brake's operating conditions (three parameters), have been modelled versus changes of the brake factor C. Based on training and testing of 18 different architectures of neural networks with five learning algorithms, a total of 90 neural models have been investigated. The neural model (BR26841) trained by the two-layered neural network, with a Bayesian regulation algorithm, was found to reach the best prediction results. This neural model was able to generalize the friction materials' cold performance, for temperatures in the contact of the friction pair T>100°C, in the range of application pressure changes between 20 and 100bar, and for initial speed changes between 20 and 100km/h.
A measuring system for experimental research on the thermomechanical coupling of disc brakes
Authors: Litos P , Honner M , Lang V , Bartik J , Hynek M
Published: July 2008

This paper deals with the introduction of a measuring system for application in research on the thermomechanical coupling of disc brakes. The first part is devoted to a description of the system for fast measurement of the brake disc surface temperature field during braking, which is the main part of the measuring system. The structure of the hardware as well as principles of evaluation of the temperature field are introduced. The second part deals with applications of the system to dynamometer testing rigs and real cars. The third part presents examples of the results. They demonstrate the applicability of the measuring system in experimental research on the behaviour of a disc brake system.
Numerical investigations of stress shielding in total hip prostheses
Authors: Behrens B-A , Wirth C J , Windhagen H , Nolte I , Meyer-Lindenberg A , Bouguecha A
Published: July 2008

Aseptic loosening of the prosthesis is still a problem in artificial joint implants. The loosening can be caused by, among other factors, resorption of the bone surrounding the prosthesis owing to stress shielding. In order to find out the influence of the prosthesis type on post-operative stress shielding, a static finite element analysis of a femur provided with the conventional uncemented stem BICONTACT and of one with the femoral neck prosthesis SPIRON was carried out. Strain energy densities and maximal principal strain distributions were calculated and compared with the physiological situation. Here, stress shielding was demonstrated in both periprosthetic femora. To determine the areas of the stress shielding, the bone in each FE model was subdivided into three regions of interest (ROI): proximal, diaphyseal, and distal. The numerical computations show stress shielding in the proximal ROI of both periprosthetic femora. Diaphyseally, the femoral neck prosthesis SPIRON, in contrast to the conventional uncemented long-stem prosthesis BICONTACT, causes no decrease in the strain distribution and thus no stress shielding. Distally, no change in the load distribution of either periprosthetic femur could be found, compared with the physiological situation.
Finite element analysis of head—neck kinematics under simulated rear impact at different accelerations
Authors: Zhang Qing Hang , Tan Soon Huat , Teo Ee Chon
Published: July 2008

The information on the variation of ligament strains over time after rear impact has been seldom investigated. In the current study, a detailed three-dimensional C0—C7 finite element model of the whole head—neck complex developed previously was modified to include T1 vertebra. Rear impact of half sine-pulses with peak values of 3.5 g, 5 g, 6.5 g and 8 g respectively were applied to the inferior surface of the T1 vertebral body to validate the simulated variations of the intervertebral segmental rotations and to investigate the ligament tensions of the cervical spine under different levels of accelerations. The simulated kinematics of the head—neck complex showed relatively good agreement with the experimental data with most of the predicted peak values falling within one standard deviation of the experimental data. Under rear impact, the whole C0—T1 structure formed an S-shaped curvature with flexion at the upper levels and extension at the lower levels at early stage after impact, during which the lower cervical levels might experience hyperextensions. The predicted high resultant strain of the capsular ligaments, even at low impact acceleration compared with other ligament groups, suggests their susceptibility to injury. The peak impact acceleration has a significant effect on the potential injury of ligaments. Under higher accelerations, most ligaments will reach failure strain in a much shorter time immediately after impact.
The effects of the spatial influence function on orthotropic femur remodelling
Authors: Shang Y , Bai J , Peng L
Published: July 2008

The morphology and internal structure of bone are modulated by the mechanical stimulus. The osteocytes can sense the stimulus signals from the adjacent regions and respond to them through bone growth or bone absorption. This mechanism can be modelled as the spatial influence function (SIF) in bone adaptation algorithm. In this paper, the remodelling process was simulated in human femurs using an adaptation algorithm with and without SIF, and the trabecular bone was assumed to be orthotropic. A different influence radius and weighting factor were adopted to study the effects of the SIF on the bone density distribution and trabecular alignment. The results have shown that the mean density and L—T ratio (the ratio of longitudinal modulus to transverse modulus) had an excellent linear relationship with the weighting factor when the influence radius was small. The characteristics of density distribution and L—T ratio accorded with the actual observation or measurement when a small weighting factor was used. The large influence radius and weighting factor led to unrealistic results. In contrast, the SIF hardly affected the trabecular alignment, as the mean variation angles of principal axes were less than 1.0 degree for any influence radius and weighting factor
Determination of pelvic ring stability: A new technique using a composite hemi-pelvis
Authors: Clements J P , Moriaty N , Chesser T J S , Ward A J , Cunningham J L
Published: July 2008

Traumatic disruption of the pelvic ring caused by high-energy impact is associated with significant mortality and morbidity. A variety of fixation techniques have been developed for treating these injuries with the main aims of restoring the stability of the pelvic ring and promoting recovery of normal function. The stability of fixation of these techniques is often analysed by cadaveric studies, which can introduce high variability into the results and have small sample numbers. This study presents a new method that uses a composite hemi-pelvis to enable stabilization of the pelvic ring to be accurately determined. The pelvis was loaded cyclically to simulate walking conditions and to assess the stability of the fixation, which was measured using a displacement transducer that monitors the motion of the pelvis in six degrees of freedom. The motions measured showed comparable results with previously published cadaveric studies. This reproducible method of testing with a hemi-pelvis composite model and rig allows valid analysis of pubic symphysis implants, obviating the difficulties of performing a cadaveric study.
A magnetic-resonance-compatible limb-positioning device to facilitate magic angle experiments in vivo
Authors: Elhawary H , Zivanovic A , Tse Z T H , Rea M , Davies B L , Young I , Bydder G , Payley M , Lamperth M U
Published: July 2008

Owing to their highly ordered structure, tendons and cartilage appear with low signal intensity when imaged using magnetic resonance imaging (MRI) scanners. A significant increase in signal can be observed when these structures are oriented at 55° (termed the magic angle) with respect to the static field B0. There is a clear clinical importance in exploiting this effect as part of the diagnosis of injury. Experimental studies of this phenomenon have been made harder by the practical difficulties associated with tissue positioning and orientation in the confined environment of closed-bore scanners. An MRI-compatible mechatronic system has been developed, which is capable of positioning a number of limbs to a desired orientation inside the scanner, to be used as a diagnostic and research tool. It is actuated with a novel pneumatic motor consisting of a heavily geared-down air turbine, presenting high torques and good accuracy. The system is shown to be magnetic resonance compatible and the results of preliminary trials using the device to image the Achilles tendon of human volunteers at different orientations are presented. An increase of four fold to thirteen fold in signal intensity can be observed at the magic angle.
Influence of contaminants in the stem—ball interface on the static fracture load of ceramic hip joint ball heads
Authors: Weisse B , Affolter C , Stutz A , Terrasi G P , Köbel S , Weber W
Published: July 2008

The probability of in-vivo failure of ceramic hip joint implants is very low (0.05–0.004 per cent). Besides material flaws and overloading, improper handling during implantation may induce fractures of the ceramic ball head in the long term. This study focuses on the influence of contaminants located in the stem—ball interface and on the use of damaged metal tapers on the strength of ceramic ball heads. Mechanical tests on alumina ball heads according to the standard ISO 7206-10 were performed to identify their effect on the static fracture load. A decrease of up to 90 per cent with respect to the reference static fracture load was found when contaminants such as bone chips, soft tissue, or blood were present. Reductions of 57 per cent and 27 per cent were observed for deformed stem cross-sections (from circular to elliptical) and for flattened stems respectively, making deformed stems another influential parameter. Since any alteration of the interface between the metal taper and the ceramic ball head yields a non-uniform load introduction and hence results in stress concentrations, its presence has to be avoided.