bluuebunny/crossref_metadata_2025 huggingface dataset:
P-cadherin expression and survival rate in oral squamous cell carcinoma:an immunohistochemical study
Authors: Lo Muzio Lorenzo , Campisi Giuseppina , Farina Antonio , Rubini Corrado , Pannone Giuseppe , Serpico Rosario , Laino Gregorio , De Lillo Alfredo , Carinci Francesco
Published: June 2005

Background

P-cadherin (P-cad) is a transmembrane molecule involved in the cell-cell adhesion and similar to E-cadherin (E-cad), but less investigated in oncology, especially in in vivo studies. Aims of the present study were to assess the prevalence of P-cad expression in oral squamous cell carcinoma (OSCC) and to verify whether P-cad can be considered a marker of prognosis in patients with OSCC.

Methods

In a retrospective study, a cohort of 67 OSCC patients was investigated for P-cad expression and its cellular localization by immunohistochemistry; some respective healthy margins of resection were similarly investigated as standard controls. After grouping for P-cad expression, OSCCs were statistically analyzed for the variables age, gender, histological grading (G), TNM, Staging, and overall survival rate. Univariate and multivariate analyses were performed.

Results

37 cases (55.2%) of OSCC showed membranous/cytoplasmic positivity for P-cad, whereas 30 (44.8 %) were negative. Although with some differences in membranous vs cytoplasmic localization of P-cad in OSCC with different G, no statistical association was found between P-cad expression and any variables considered at baseline. In terms of prognostic significance, P-cad non expression was found to have an independent association with poorer overall survival rate than P-cad expressing group (P = 0.056); moreover, among P-cad +ve patients the best prognosis was for those OSCC with membranous (P < 0.0001) than those with cytoplasmic P-cad expression.

Conclusion

On the basis of these results, it is possible to suggest P-cad as an early marker of poor prognosis. The abnormal or lack of P-cad expression could constitute an hallmark of aggressive biological behavior in OSCC
Bone mineral density measurement and osteoporosis treatment after a fragility fracture in older adults: regional variation and determinants of use in Quebec
Authors: Vanasse Alain , Dagenais Pierre , Niyonsenga Théophile , Grégoire Jean-Pierre , Courteau Josiane , Hemiari Abbas
Published: June 2005

Background

Osteoporosis (OP) is a skeletal disorder characterized by reduced bone strength and predisposition to increased risk of fracture, with consequent increased risk of morbidity and mortality. It is therefore an important public health problem. International and Canadian associations have issued clinical guidelines for the diagnosis and treatment of OP. In this study, we identified potential predictors of bone mineral density (BMD) testing and OP treatment, which include place of residence.

Methods

Our study was a retrospective population-based cohort study using data from the Quebec Health Insurance Board. The studied population consisted of all individuals 65 years and older for whom a physician claimed a consultation for a low velocity vertebral, hip, wrist, or humerus fracture in 1999 and 2000. Individuals were considered to have undergone BMD testing if there was a claim for such a procedure within two years following a fracture. They were considered to have received an OP treatment if there was at least one claim to Quebec's health insurance plan (RAMQ) for OP treatment within one year following a fracture. We performed descriptive analyses and logistic regressions by gender. Predictors included age, site of fracture, social status, comorbidity index, prior BMD testing, prior OP treatment, long-term glucocorticoid use, and physical distance to BMD device.

Results

The cohort, 77% of which was female, consisted of 25,852 individuals with fragility fractures. BMD testing and OP treatment rates were low and gender dependent (BMD: men 4.6%; women 13.1%; OP treatment: men 9.9%; women 29.7%). There was an obvious regional variation, particularly in BMD testing, ranging from 0 to 16%. Logistic regressions demonstrate that individuals living in long term care facilities received less BMD testing. Patients who had suffered from vertebral fractures, or who had received prior OP treatment or BMD testing, regardless of gender, subsequently received more BMD testing and OP treatments. Furthermore, increasing the distance between a patient's residence and BMD facility precluded likelihood of BMD testing.

Conclusion

BMD testing rate was extremely low but not completely explained by reduced physical access; gender, age, social status, prior BMD testing and OP treatment were all important predictors for future BMD testing and OP treatment.
Adenosine infusion increases plasma levels of VEGF in humans
Authors: Adair Thomas H , Cotten Reid , Gu Jian-Wei , Pryor Janelle S , Bennett Kenneth R , McMullan Michael R , McDonnell Preston , Montani Jean-Pierre
Published: June 2005

Background

Many in vitro studies have shown that adenosine (Ado) can induce vascular endothelial growth factor (VEGF) mRNA and protein expression and stimulate endothelial proliferation. In the present study, we seek to determine whether Ado can increase circulating levels of VEGF protein in the intact human.

Methods

Five outpatients 49.3 ± 6.7 years of age and weighing 88.2 ± 8.5 kg were selected. They were given a 6 min intravenous infusion of Ado (0.14 mg kg-1 min-1) in conjunction with sestamibi myocardial perfusion scans. Mean blood pressure (MBP, calculated from systolic and diastolic values) and heart rate (HR) were determined before Ado infusion and every 2 min for the next 10 min. Plasma VEGF concentrations (ELISA) were determined immediately before Ado infusion and 1 h, 2 h, and 8 h after the infusion.

Results

Plasma VEGF concentration averaged 20.3 ± 2.0 pg ml-1 prior to Ado infusion, and increased to 62.7 ± 18.1 pg ml-1 at 1 h post- infusion (p < 0.01). VEGF plasma concentration returned to basal levels 2 h after infusion (23.3 ± 3.4 pg ml-1). MBP averaged 116 ± 7 mmHg and heart rate averaged 70 ± 7 prior to Ado infusion. MBP decreased by a maximum of ~22% and HR increased by a maximum of ~17% during the infusion.

Conclusion

We conclude from these preliminary findings that intravenous infusion of adenosine can increase plasma levels of VEGF in humans.
Evidence-based patient choice: a prostate cancer decision aid in plain language
Authors: Holmes-Rovner Margaret , Stableford Sue , Fagerlin Angela , Wei John T , Dunn Rodney L , Ohene-Frempong Janet , Kelly-Blake Karen , Rovner David R
Published: June 2005

Background

Decision aids (DA) to assist patients in evaluating treatment options and sharing in decision making have proliferated in recent years. Most require high literacy and do not use plain language principles. We describe one of the first attempts to design a decision aid using principles from reading research and document design. The plain language DA prototype addressed treatment decisions for localized prostate cancer. Evaluation assessed impact on knowledge, decisions, and discussions with doctors in men newly diagnosed with prostate cancer.

Methods

Document development steps included preparing an evidence-based DA in standard medical parlance, iteratively translating it to emphasize shared decision making and plain language in three formats (booklet, Internet, and audio-tape). Scientific review of medical content was integrated with expert health literacy review of document structure and design. Formative evaluation methods included focus groups (n = 4) and survey of a new sample of men newly diagnosed with prostate cancer (n = 60), compared with historical controls (n = 184).

Results

A transparent description of the development process and design elements is reported. Formative evaluation among newly diagnosed prostate cancer patients found the DA to be clear and useful in reaching a decision. Newly diagnosed patients reported more discussions with doctors about treatment options, and showed increases in knowledge of side effects of radiation therapy.

Conclusion

The plain language DA presenting medical evidence in text and numerical formats appears acceptable and useful in decision-making about localized prostate cancer treatment. Further testing should evaluate the impact of all three media on decisions made and quality of life in the survivorship period, especially among very low literacy men.
A Severe Acute Respiratory Syndrome extranet: supporting local communication and information dissemination
Authors: Valaitis Ruta K , Akhtar-Danesh Noori , Kealey Cathy M , Brunetti Glenn M , Thomas Helen
Published: June 2005

Background

The objective of this study was to explore the use and perceptions of a local Severe Acute Respiratory Syndrome (SARS) Extranet and its potential to support future information and communication applications. The SARS Extranet was a single, managed electronic and limited access system to manage local, provincial and other SARS control information.

Methods

During July, 2003, a web-based and paper-based survey was conducted with 53 SARS Steering Committee members in Hamilton. It assessed the use and perceptions of the Extranet that had been built to support the committee during the SARS outbreak. Before distribution, the survey was user-tested based on a think-aloud protocol, and revisions were made. Quantitative and qualitative questions were asked related to frequency of use of the Extranet, perceived overall usefulness of the resource, rationale for use, potential barriers, strengths and limitations, and potential future uses of the Extranet.

Results

The response rate was 69.4% (n = 34). Of all respondents, 30 (88.2%) reported that they had visited the site, and rated it highly overall (mean = 4.0; 1 = low to 5 = high). However, the site was rated 3.4 compared with other communications strategies used during the outbreak. Almost half of all respondents (44.1%) visited the site at least once every few days. The two most common reasons the 30 respondents visited the Extranet were to access SARS Steering Committee minutes (63.3%) and to access Hamilton medical advisories (53.3%). The most commonly cited potential future uses for the Extranet were the sending of private emails to public health experts (63.3%), and surveillance (63.3%). No one encountered personal barriers in his or her use of the site, but several mentioned that time and duplication of email information were challenges.

Conclusion

Despite higher rankings of various communication strategies during the SARS outbreak, such as email, meetings, teleconferences, and other web sites, users generally perceived a local Extranet as a useful support for the dissemination of local information during public health emergencies.
Real time spatial cluster detection using interpoint distances among precise patient locations
Authors: Olson Karen L , Bonetti Marco , Pagano Marcello , Mandl Kenneth D
Published: June 2005

Background

Public health departments in the United States are beginning to gain timely access to health data, often as soon as one day after a visit to a health care facility. Consequently, new approaches to outbreak surveillance are being developed. When cases cluster geographically, an analysis of their spatial distribution can facilitate outbreak detection. Our method focuses on detecting perturbations in the distribution of pair-wise distances among all patients in a geographical region. Barring outbreaks, this distribution can be quite stable over time. We sought to exemplify the method by measuring its cluster detection performance, and to determine factors affecting sensitivity to spatial clustering among patients presenting to hospital emergency departments with respiratory syndromes.

Methods

The approach was to (1) define a baseline spatial distribution of home addresses for a population of patients visiting an emergency department with respiratory syndromes using historical data; (2) develop a controlled feature set simulation by inserting simulated outbreak data with varied parameters into authentic background noise, thereby creating semisynthetic data; (3) compare the observed with the expected spatial distribution; (4) establish the relative value of different alarm strategies so as to maximize sensitivity for the detection of clustering; and (5) measure factors which have an impact on sensitivity.

Results

Overall sensitivity to detect spatial clustering was 62%. This contrasts with an overall alarm rate of less than 5% for the same number of extra visits when the extra visits were not characterized by geographic clustering. Clusters that produced the least number of alarms were those that were small in size (10 extra visits in a week, where visits per week ranged from 120 to 472), diffusely distributed over an area with a 3 km radius, and located close to the hospital (5 km) in a region most densely populated with patients to this hospital. Near perfect alarm rates were found for clusters that varied on the opposite extremes of these parameters (40 extra visits, within a 250 meter radius, 50 km from the hospital).

Conclusion

Measuring perturbations in the interpoint distance distribution is a sensitive method for detecting spatial clustering. When cases are clustered geographically, there is clearly power to detect clustering when the spatial distribution is represented by the M statistic, even when clusters are small in size. By varying independent parameters of simulated outbreaks, we have demonstrated empirically the limits of detection of different types of outbreaks.
Immediate transfection of patient-derived leukemia: a novel source for generating cell-based vaccines
Authors: Gershan Jill A , Johnson Bryon D , Weber James , Schauer Dennis W , Natalia Natalia , Behnke Stephanie , Burns Karen , Maloney Kelly W , Warwick Anne B , Orentas Rimas J
Published: June 2005

Background

The production of cell-based cancer vaccines by gene vectors encoding proteins that stimulate the immune system has advanced rapidly in model systems. We sought to develop non-viral transfection methods that could transform patient tumor cells into cancer vaccines, paving the way for rapid production of autologous cell-based vaccines.

Methods

As the extended culture and expansion of most patient tumor cells is not possible, we sought to first evaluate a new technology that combines electroporation and chemical transfection in order to determine if plasmid-based gene vectors could be instantaneously delivered to the nucleus, and to determine if gene expression was possible in a cell-cycle independent manner. We tested cultured cell lines, a primary murine tumor, and primary human leukemia cells from diagnostic work-up for transgene expression, using both RFP and CD137L expression vectors.

Results

Combined electroporation-transfection directly delivered plasmid DNA to the nucleus of transfected cells, as demonstrated by confocal microscopy and real-time PCR analysis of isolated nuclei. Expression of protein from plasmid vectors could be detected as early as two hours post transfection. However, the kinetics of gene expression from plasmid-based vectors in tumor cell lines indicated that optimal gene expression was still dependent on cell division. We then tested to see if pediatric acute lymphocytic leukemia (ALL) would also display the rapid gene expression kinetics of tumor cells lines, determining gene expression 24 hours after transfection. Six of 12 specimens showed greater than 17% transgene expression, and all samples showed at least some transgene expression.

Conclusion

Given that transgene expression could be detected in a majority of primary tumor samples analyzed within hours, direct electroporation-based transfection of primary leukemia holds the potential to generate patient-specific cancer vaccines. Plasmid-based gene therapy represents a simple means to generate cell-based cancer vaccines and does not require the extensive infrastructure of a virus-based vector system.
Ovarian cancer, the coagulation pathway, and inflammation
Authors: Wang Xipeng , Wang Ena , Kavanagh John J , Freedman Ralph S
Published: June 2005

Epithelial ovarian cancer (EOC) represents the most frequent cause of death in the United States from a cancer involving the female genital tract. Contributing to the overall poor outcome in EOC patients, are the metastases to the peritoneum and stroma that are common in this cancer. In one study, cDNA microarray analysis was performed on fresh tissue to profile gene expression in patients with EOC. This study showed a number of genes with significantly altered expression in the pelvic peritoneum and stroma, and in the vicinity of EOC implants. These genes included those encoding coagulation factors and regulatory proteins in the coagulation cascade and genes encoding proteins associated with inflammatory responses. In addition to promoting the formation of blood clots, coagulation factors exhibit many other biologic functions as well as tumorigenic functions, the later including tumor cell proliferation, angiogenesis, invasion, and metastasis. Coagulation pathway proteins involved in tumorigenesis consist of factor II (thrombin), thrombin receptor (protease-activated receptors), factor III (tissue factor), factor VII, factor X and factor I (fibrinogen), and fibrin and factor XIII. In a recent study we conducted, we found that factor XII, factor XI, and several coagulation regulatory proteins, including heparin cofactor-II and epithelial protein C receptor (EPCR), were also upregulated in the peritoneum of EOC.

In this review, we summarize evidence in support of a role for these factors in promoting tumor cell progression and the formation of ascites. We also discuss the different roles of coagulation factor pathways in the tumor and peritumoral microenvironments as they relate to angiogenesis, proliferation, invasion, and metastasis. . Since inflammatory responses are another characteristic of the peritoneum in EOC, we also discuss the linkage between the coagulation cascade and the cytokines/chemokines involved in inflammation. Interleukin-8, which is considered an important chemokine associated with tumor progression, appears to be a linkage point for coagulation and inflammation in malignancy. Lastly, we review findings regarding the inflammatory process yielded by certain clinical trials of agents that target members of the coagulation cascade in the treatment of cancer. Current data suggest that disrupting certain elements of the coagulation and inflammation processes in the tumor microenvironment could be a new biologic approach to cancer therapeutics.
The ups and downs of biological timers
Authors: Rappaport Noa , Winter Shay , Barkai Naama
Published: June 2005

Background

The need to execute a sequence of events in an orderly and timely manner is central to many biological processes, including cell cycle progression and cell differentiation. For self-perpetuating systems, such as the cell cycle oscillator, delay times between events are defined by the network of interacting proteins that propagates the system. However, protein levels inside cells are subject to genetic and environmental fluctuations, raising the question of how reliable timing is maintained.

Results

We compared the robustness of different mechanisms for encoding delay times to fluctuations in protein expression levels. Gradual accumulation and gradual decay of a regulatory protein have an equivalent capacity for defining delay times. Yet, we find that the former is highly sensitive to fluctuations in gene dosage, while the latter can buffer such perturbations. In particular, a positive feedback where the degrading protein auto-enhances its own degradation may render delay times practically insensitive to gene dosage.

Conclusion

While our understanding of biological timing mechanisms is still rudimentary, it is clear that there is an ample use of degradation as well as self-enhanced degradation in processes such as cell cycle and circadian clocks. We propose that degradation processes, and specifically self-enhanced degradation, will be preferred in processes where maintaining the robustness of timing is important.
TRIM5α selectively binds a restriction-sensitive retroviral capsid
Authors: Sebastian Sarah , Luban Jeremy
Published: June 2005

TRIM5 is a potent retrovirus inhibitor that targets viruses bearing particular capsid (CA) residues. In most primate species, retroviral restriction requires the C-terminal SPRY domain unique to the α-isoform of TRIM5, but the mechanism by which susceptible viruses are recognized and targeted for restriction is unknown. Here we show that TRIM5α binds retroviral CA from detergent-stripped virions in a SPRY-dependent manner with sufficient discrimination to account for the exquisite specificity of restriction.
Giant viruses in the oceans: the 4th Algal Virus Workshop
Authors: Claverie Jean-Michel
Published: June 2005

Giant double-stranded DNA viruses (such as record breaking Acanthamoeba polyphaga Mimivirus), with particle sizes of 0.2 to 0.6 μm, genomes of 300 kbp to 1.200 kbp, and commensurate complex gene contents, constitute an evolutionary mystery. They challenge the common vision of viruses, traditionally seen as highly streamlined genomes optimally fitted to the smallest possible -filterable- package. Such giant viruses are now discovered in increasing numbers through the systematic sampling of ocean waters as well as freshwater aquatic environments, where they play a significant role in controlling phyto- and bacterio- plankton populations. The 4th algal virus workshop showed that the study of these ecologically important viruses is now massively entering the genomic era, promising a better understanding of their diversity and, hopefully, some insights on their origin and the evolutionary forces that shaped their genomes.
High frequency oscillatory ventilation compared with conventional mechanical ventilation in adult respiratory distress syndrome: a randomized controlled trial [ISRCTN24242669]
Authors: Bollen Casper W , van Well Gijs Th J , Sherry Tony , Beale Richard J , Shah Sanjoy , Findlay George , Monchi Mehran , Chiche Jean-Daniel , Weiler Norbert , Uiterwaal Cuno SPM , van Vught Adrianus J
Published: June 2005

Introduction

To compare the safety and efficacy of high frequency oscillatory ventilation (HFOV) with conventional mechanical ventilation (CV) for early intervention in adult respiratory distress syndrome (ARDS), a multi-centre randomized trial in four intensive care units was conducted.

Methods

Patients with ARDS were randomized to receive either HFOV or CV. In both treatment arms a priority was given to maintain lung volume while minimizing peak pressures. CV ventilation strategy was aimed at reducing tidal volumes. In the HFOV group, an open lung strategy was used. Respiratory and circulatory parameters were recorded and clinical outcome was determined at 30 days of follow up.

Results

The study was prematurely stopped. Thirty-seven patients received HFOV and 24 patients CV (average APACHE II score 21 and 20, oxygenation index 25 and 18 and duration of mechanical ventilation prior to randomization 2.1 and 1.5 days, respectively). There were no statistically significant differences in survival without supplemental oxygen or on ventilator, mortality, therapy failure, or crossover. Adjustment by a priori defined baseline characteristics showed an odds ratio of 0.80 (95% CI 0.22–2.97) for survival without oxygen or on ventilator, and an odds ratio for mortality of 1.15 (95% CI 0.43–3.10) for HFOV compared with CV. The response of the oxygenation index (OI) to treatment did not differentiate between survival and death. In the HFOV group the OI response was significantly higher than in the CV group between the first and the second day. A post hoc analysis suggested that there was a relatively better treatment effect of HFOV compared with CV in patients with a higher baseline OI.

Conclusion

No significant differences were observed, but this trial only had power to detect major differences in survival without oxygen or on ventilator. In patients with ARDS and higher baseline OI, however, there might be a treatment benefit of HFOV over CV. More research is needed to establish the efficacy of HFOV in the treatment of ARDS. We suggest that future studies are designed to allow for informative analysis in patients with higher OI.
Struggling with the Fragility of Life: a relational-narrative approach to ethics in palliative nursing
Authors: Abma Tineke A
Published: June 2005

In nursing ethics the role of narratives and dialogue has become more prominent in recent years. The purpose of this article is to illuminate a relational-narrative approach to ethics in the context of palliative nursing. The case study presented concerns a difficult relationship between oncology nurses and a husband whose wife was hospitalized with cancer. The husband’s narrative is an expression of depression, social isolation and the loss of hope. He found no meaning in the process of dying and death. The oncology nurses were not able to recognize his emotional and existential problems. A narrative perspective inspired by relational ethics indicates that participants may develop a relational narrative that seeks good for all involved in a situation. In palliative nursing this entails open communication about the fragility of life and approaching death. In relational narratives, answers to these ethical dilemmas are co-authored, contingent and contextual.
Advance Directives: the New Zealand context
Authors: Wareham Pauline , McCallin Antoinette , Diesfeld Kate
Published: June 2005

Advance directives convey consumers’ wishes about accepting or refusing future treatment if they become incompetent. They are designed to communicate a competent consumer’s perspective regarding the preferred treatment, should the consumer later become incompetent. There are associated ethical issues for health practitioners and this article considers the features that are relevant to nurses. In New Zealand, consumers have a legal right to use an advance directive that is not limited to life-prolonging care and includes general health procedures. Concerns may arise regarding a consumer’s competence and the document’s validity. Nurses need to understand their legal and professional obligations to comply with an advance directive. What role does a nurse play and what questions arise for a nurse when advance directives are discussed with consumers? This article considers the cultural dimensions, legal boundaries, consumers’ and providers’ perspectives, and the medical and nursing positions in New Zealand.
Introductory Engagement Within the Perinatal Nursing Relationship
Authors: Goldberg Lisa Sara
Published: June 2005

In this article, the theme of introductory engagement is developed through the conversational interviews and participatory observations I carried out with perinatal nurses and birthing women in the context of a feminist phenomenological methodology. Positioned against the landscape of hierarchical health care practices embedded with power dynamics and disembodied practices, this research explored the ways in which perinatal nurses related to birthing women in the context of relational care. The focus of attention in this article is to describe the theme of introductory engagement by way of a storied phenomenological text.
Brown-Vialetto-Van Laere syndrome: a rare syndrome in otology - case report and literature review
Authors: Prabhu H V , Brown M J K
Published: June 2005

Brown-Vialetto-Van Laere syndrome, or pontobulbar palsy with deafness, is a rare disorder characterized by bilateral sensorineural deafness and a variety of cranial nerve disorders usually involving the motor components of the lower cranial nerves. Less commonly, spinal motor nerves and upper motor neurons are involved. Familial and sporadic cases have been reported. Based on evidences, this syndrome has been related to autosomal recessive, autosomal dominant and X-linked inheritance. Autoimmune origin has been considered as well.

In this paper, we report the case of a 38-year-old female patient who primarily presented with bilateral sensorineural hearing loss and then progressively developed Xth and VIIth cranial nerve paralysis. Brown-Vialetto-Van Laere syndrome was diagnosed with this symptom complex of sensorineural hearing loss and pontobulbar palsy.
Influence of the dilute‐solution properties of cellulose acetate in solvent mixtures on the morphology and pervaporation performance of their membranes
Authors: Qian J. W. , An Q. F. , Wang L. N. , Zhang L. , Shen L.
Published: June 2005

The pervaporation performance of cellulose acetate (CA) membranes prepared from acetone (AC), acetone/tetrahydrofuran (AC/THF), acetone/chloroform (AC/CF), and acetone/cyclohexane (AC/CYH) was studied for separating MeOH/MTBE (methyl tert‐butyl ether) mixture with 5 (wt) % MeOH. The dilute‐solution properties and Huggins constant (KH) of CA dissolved in AC and AC/solvent mixtures with 15 vol % of the second solvent (tetrahydrofuran, chloroform, or cyclohexane) were examined. J and α of the CA membranes were affected by the types of solvent mixtures used to prepare the casting solutions. Under the same conditions, the membrane with AC/CYH had the highest J value and the lowest α value, and it was followed by the membranes with AC/CF, AC/THF, and AC. The increasing value of J and decreasing value of α for the CA membranes from different solvent mixtures were in good agreement with the increasing value of KH of CA in corresponding solvent mixtures. Furthermore, differences in the morphology from scanning electron microscopy images of the cross sections or from atomic force microscopy photographs of the surfaces of the membranes existed, and they provided proof of the different pervaporation performances of the CA membranes prepared from AC and AC/solvent mixtures. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97:1891–1898, 2005
Deformation mechanism of polypropylene composites filled with magnesium hydroxide
Authors: Yin Jun , Zhang Yong , Zhang Yinxi
Published: June 2005

The fracture behavior and deformation mechanism of polypropylene (PP) composites filled with magnesium hydroxide [Mg(OH)2] were investigated. The incorporation of Mg(OH)2 particles into the PP matrix led to an increase in Young's modulus and a significant reduction in the tensile yield strength and elongation at break. Surface modification on filler particles with stearic acid could reduce the interfacial adhesion between the filler and PP matrix and improve the stress transferability. The deformation mechanism of the Mg(OH)2/PP composites depended on the interfacial adhesion and the deformability of ligaments between microvoids caused by debonding. The deformability of the ligaments could be significantly improved by surface modification on the particle surface. The dependence of the deformation behavior of the Mg(OH)2/PP composites on the filler content was in accordance with percolation theory. The agglomeration of microvoids and fibrillation of ligaments in the PP composites with excessive filler content indicated the weak resistance of the polymer matrix to crack propagation and premature fracture in a brittle manner. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1922–1930, 2005
Novel intercalated nanocomposites of polypropylene/organic‐rectorite/polyethylene‐octene elastomer: Rheology, crystallization kinetics, and thermal properties
Authors: Ma Xiao‐Yan , Liang Guo‐Zheng , Liu Hai‐Lin , Fei Jing‐Yin , Huang Yun
Published: June 2005

The melt blending method was applied to prepare ternary composites of polypropylene (PP)/organic‐rectorite (OREC)/polyethylene‐octene elastomer (POE) at constant content of 2 phr (parts per hundred PP) of OREC and 5, 10, 15 phr of POE (named PRE25, PRE210, and PRE215, separately) via twin‐screw extruder. At the same time the binary composites of OREC/PP at 2 phr loading of OREC, named PR2 were prepared in order to investigate effects of OREC and POE on rheology and crystallization properties of composites. The rheology was characterized on capillary rheometer, nonisothermal crystallization kinetics on differential scanning calorimetry (DSC), and thermal stability properties on thermogravimetric analysis (TG). It is found that melting PR2 and PRE systems conform to the law of Non‐Newton and shear‐thinning behavior is observed for both systems. The apparent viscosity of the melt decreases with the increase of POE loadings. The crystallization halftime (t1/2) of PRE is shorter, the rate constant Zc larger, which indicates OREC and POE has the heterogeneous nucleation effect and the crystallization rate of PP was increased. The enthalpy of PRE is lower than that of PR2 and pure PP at the same conditions, which shows that the relative crystallinity of PRE composites are reduced. TG curves show that the ternary systems have higher thermal stability in contrast with pure PP. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1915–1921, 2005
Preparation and glass transition temperature of hyperbranched poly[allyl methyl maleate‐co‐N‐propyl maleimide]
Authors: Liu Hewen , Wilén Carl‐Eric
Published: June 2005

The kinetics and molecular weight averages of the hyperbranched polymers formed by the alternating copolymerization of equimolar allyl methyl maleate (AMM) and N‐n‐propyl maleimide (PMI) were investigated. The yields, molecular weight averages, and polydispersity indices as well as the branching degrees of the produced copolymers increased with increasing initiator concentrations and prolonged polymerization time. The trends of the experimental molecular weights as determined by size exclusion chromatography were in good agreement with the theoretical predictions. The molecular weight distribution indices fit the curve given by Mw/Mn = 1/(1‐xD), and the molecular weights fit the curve given by Mw = 4076/(1‐xD)2, where xD was the conversion of vinyl groups. DSC studies demonstrated a nonlinear relation of Tg values to the reciprocal of molecular weight (M), and Tg values decreased with the increase of molecular weight. For the Tg values of highly branched polymers in high molecular weight range, a relation of Tg = T + k/M was obtained, where T was obtained by extrapolating to infinite molecular weight and k was a constant. T was 136°C, and k = 2.9 for this work. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1941–1947, 2005
Interactions in blends containing chitosan with functionalized polymers
Authors: Castro Cristian , Gargallo Ligia , Leiva Angel , Radić Deodato
Published: June 2005

The phase behavior of blends containing chitosan with poly(vinyl‐alcohol) (PVA) and poly(2‐hidroxyethyl methacrylate) (P2HEM) was analyzed. Blends were obtained by casting from acetic acid solution (HAc) and 1,1,1,3,3,3 hexafluoro‐2‐propanol (HF2P) and studied by DSC, FT‐IR, and TGA. The phase behavior of the blends of chitosan with PVA and P2HEM, studied by DSC, shows that the systems behave as one‐phase systems in HAc as well as in HF2P according to the DSC results. According to the results of FT‐IR analyses of the different absorptions of the blends, relative to the pure components, they show an important shift that is considered evidence of an interaction between the components of the blends. The thermogravimetric analysis of the blends and the pure components shows that the temperature for thermal degradation of the blends is higher that that of the pure components, irrespective of the solvent casting from which the mixture was obtained. These results are interpreted as the formation of a new product that corresponds to a compatible polymer blend. The compatibilization of these systems is attributed to strong interactions, like hydrogen bonds formation between the functionalized polymers and chitosan, due to the presence of interacting functional groups in all the polymers studied. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1953–1960, 2005
Enhancement of hydrolytic stability and adhesion of waterborne polyurethanes
Authors: Kim Bum Soo , Kim Byung Kyu
Published: June 2005

A new type of polyester polyol, with alkyl side groups, viz. poly(2,4‐diethyl‐1,5‐pentamethylene adipate) glycol (PDPAd) was synthesized and used to improve the hydrolytic stability of waterborne polyurethanes (PU). The results compared favorably with poly(tetramethylene adipate) glycol (PTAd)–based PU and blends of the two types of PU in terms of particle size, thermal, XRD, mechanical, dynamic mechanical, and swell behavior of the dispersion cast films in addition to hydrolytic stability and adhesion properties. Blends of PTAd‐based PU and PDPAd‐based PU gave significantly improved green (immediate) adhesion and hydrolytic stability due to the synergistic effects of crystallinity (heat of crystallization, high density) and amorphous regions (tack, high thermal stability). © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1961–1969, 2005
Using genomewide mutagenesis screens to identify the genes required for neural tube closure in the mouse
Authors: Zohn Irene E. , Anderson Kathryn V. , Niswander Lee
Published: June 2005

BACKGROUND

Neural tube closure is a critical embryological process that requires the coordination of many molecular and cellular events. Only recently has the molecular basis of the cell movements that drive neural tube closure begun to be elucidated. This has been accomplished in part due to the analysis of a growing number of genetically targeted and naturally occurring mouse mutant strains that have neural tube defects (NTDs). Currently there are more than 100 genes that when mutated result in NTDs in the mouse. Yet only approximately 10% of genes in the mouse genome have been mutated and their gross phenotype analyzed, suggesting that only a small percentage of the genes that can cause NTDs have been identified.

METHODS

In order to more systematically and fully understand the genetic basis of neural tube closure and to begin to define the molecular pathways that direct this key embryonic event, our laboratories have undertaken a forward genetic screen in mice. From this we hope to gain a better understanding of the regulation of this complex morphogenic processes.

CONCLUSIONS

The mouse provides a good model for human neural tube closure, and therefore the information gained from generating novel mouse models of NTDs will help to predict the genes responsible for human NTDs and provide experimental evidence for how they function. Birth Defects Research (Part A), 2005. © 2005 Wiley‐Liss, Inc.
A Low‐Cost Biofuel Cell with pH‐Dependent Power Output Based on Porous Carbon as Matrix
Authors: Liu Ying , Wang Mingkui , Zhao Feng , Liu Baifeng , Dong Shaojun
Published: June 2005

A glucose/O2 biofuel cell (BFC) possessing a pH‐dependent power output was fabricated by taking porous carbon (PC) as the matrix to load glucose oxidase or fungi laccase as the catalysts. The electrolytes in the anode and cathode compartments contain ferrocene monocarboxylic acid and 2,2′‐azino‐bis‐(3‐ethylbenzthiazoline‐6‐sulfonic acid) diammonium salt as the mediators, respectively. The power of the BFC was enhanced significantly by using PC as the matrix, rather than glassy carbon electrode. Additionally, the power output of the BFC decreases as the pH of the solution increases from 4.0 to 7.0, which provides a simple and efficient method to achieve the required power output. More importantly, the BFC can operate at pH 6.0, and even at pH 7.0, which overcomes the requirement for cathode solutions of pH<5.0 when using fungi laccase as a catalyst. Operation of the BFC at neutral pH may provide a means to power medical devices implanted in physiological systems. The facile and low‐cost fabrication of this BFC may enable its development for other applications.
Crystal Structures of the ScCuSe2 and Sc3CuSn3Se11 Compounds.
Authors: Gulay L. D. , Shemet V. Ya. , Olekseyuk I. D.
Published: June 2005

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Crystal Structure and Charge Density Analysis of Li2NH by Synchrotron X‐Ray Diffraction.
Authors: Noritake T. , Nozaki H. , Aoki M. , Towata S. , Kitahara G. , Nakamori Y. , Orimo S.
Published: June 2005

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Cyrstal Structure of a New Compound Ag5Dy7Sb.
Authors: Zeng Lingmin , Xu Xiaojie , Cai Gemei
Published: June 2005

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Crystal Structure and Mechanical Properties of SrSi7N10.
Authors: Pilet Guillaume , Hoeppe Henning A. , Schnick Wolfgang , Esmaeilzadeh Saeid
Published: June 2005

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B5C5 Anionic Molecules Trapped in a Solid Matrix: The Crystal and Electronic Structures of LaBC.
Authors: Babizhetskyy Volodymyr , Mattausch Hansjuergen , Gautier Regis , Bauer Josef , Halet Jean‐Francois , Simon Arndt
Published: June 2005

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Luminescence Properties of Europium Activated SrIn2O4.
Authors: Baszczuk A. , Jasiorski M. , Nyk M. , Hanuza J. , Maczka M. , Strek W.
Published: June 2005

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Preparation and Characterization of Thin Film Li4Ti5O12 Electrodes by Magnetron Sputtering.
Authors: Wang C.‐L. , Liao Y. C. , Hsu F. C. , Tai N. H. , Wu M. K.
Published: June 2005

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Synthesis, Structure, and Catalytic Properties of Rare‐Earth Ternary Sulfates.
Authors: Perles Josefina , Fortes‐Revilla Carlos , Gutierrez‐Puebla Enrique , Iglesias Marta , Monge M. Angeles , Ruiz‐Valero Caridad , Snejko Natalia
Published: June 2005

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Synthesis, Crystal Structure, and Vibrational Spectra of Ca4P6O19 (Troemelite) — A catena‐Hexaphosphate.
Authors: Hoeppe Henning A.
Published: June 2005

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Synthesis and Structure of Mixed‐Valent Gallium Subhalides: Molecular, Donor‐Stabilized Ga5X7 Species (X: Cl, Br).
Authors: Duan Taike , Stoesser Gregor , Schnoeckel Hansgeorg
Published: June 2005

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The Crystal Structure of Tl3Bi2I9: A Complex Defect and Deformation Variant of the Perovskite Structure Type.
Authors: Wosylus Aron , Schwarz Ulrich , Ruck Michael
Published: June 2005

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Enantioselective Epoxidation of Unfunctionalized Olefins Catalyzed by Mn(salen) Complexes Immobilized in Porous Materials via Phenyl Sulfonic Group.
Authors: Zhang Huidong , Xiang Song , Li Can
Published: June 2005

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Polymer‐Supported Chiral Phosphinooxazolidine Ligands for Pd‐Catalyzed Asymmetric Allylic Substitution.
Authors: Kim Young‐Mok , Jin Myung‐Jong
Published: June 2005

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Unprecedented Carbocyclization of 1,6‐Allenynes on Addition of Organoboronic Acids under Pd‐Catalysis.
Authors: Gupta Arun Kumar , Rhim Chul Yun , Oh Chang Ho
Published: June 2005

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An Efficient PMo11VVO4‐40/Silica Material Having Cationic Ammonium Moiety: Synthesis, Characterization, and Catalytic Performance for Oxidation of Alcohols with Dioxygen.
Authors: Kato Chika N. , Tanabe Akiko , Negishi Satoshi , Goto Kazuhiro , Nomiya Kenji
Published: June 2005

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Ruthenium Catalyzed Oxidation of 1,2‐Diols to 1,2‐Diketones Using Bromamine‐T as an Oxidizing Agent.
Authors: Jain Suman L. , Sharma Vishal B. , Sain Bir
Published: June 2005

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Efficient Role of Mg‐ZnCl2 for Selective Reduction of α,β‐Unsaturated Carbonyl Compounds in Aqueous Medium.
Authors: Saikia Anil , Barthakur Madan Gopal , Boruah Romesh Chandra
Published: June 2005

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Transfer Hydrogenation of Aromatic Nitro Compounds Using Polymer‐Supported Formate and Pd‐C.
Authors: Abiraj K. , Srinivasa G. R. , Gowda D. Channe
Published: June 2005

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Nitration of Aromatic Compounds by Zn(NO3)2×2N2O4 and Its Charcoal‐Supported System.
Authors: Iranpoor Nasser , Firouzabadi Habib , Heydari Reza , Shiri Morteza
Published: June 2005

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N‐Alkylation of Phthalimide, Carboxamide, and Sulfonamides by Oxidation—Reduction Condensation Using Di‐tert‐butyl‐1,4‐benzoquinone and Alkyl Diphenylphosphinite.
Authors: Mukaiyama Teruaki , Aoki Hidenori
Published: June 2005

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Barbier‐Type Reaction Mediated with Tin Nano‐Particles in Water.
Authors: Zha Zhenggen , Qiao Shu , Jiang Jiaoyang , Wang Yusong , Miao Qian , Wang Zhiyong
Published: June 2005

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1‐Butyl‐3‐methyl‐imidazolium Tetrafluoroborate as a Recyclable Reaction Medium for Henry Reaction.
Authors: Khan Faiz Ahmed , Sudheer Ch. , Sahu Nilam
Published: June 2005

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Conversion of α,β‐Unsaturated Aldehydes into Saturated Esters: An Umpolung Reaction Catalyzed by Nucleophilic Carbenes.
Authors: Chan Audrey , Scheidt Karl A.
Published: June 2005

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PS‐IIDQ: An Efficient Polymer‐Supported Amide Coupling Reagent.
Authors: Valeur Eric , Bradley Mark
Published: June 2005

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2‐(Prenyloxymethyl)benzoyl (POMB) as a New Temporary Protecting Group for Alcohols.
Authors: Vatele Jean‐Michel
Published: June 2005

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Lithiation of 1‐Arylimidazol‐2(1H)‐ones and 1‐Aryl‐4,5‐dihydroimidazol‐2(1H)‐ones.
Authors: Llopart Carme Cantos , Ferrer Conchita , Joule John A.
Published: June 2005

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Sterically Stabilized Cyclopropenonophanes and an Electronically Stabilized Cyclopropenethionophane: Syntheses, Structural Properties, and Reactivity.
Authors: Werz Daniel B. , Schuster Andreea , Gleiter Rolf , Rominger Frank
Published: June 2005

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Chromium(III)‐Catalyzed Synthesis of Allenes from Propargyl Derivatives via a Carbometalation—Elimination Sequence.
Authors: Molander Gary A. , Sommers Erin M.
Published: June 2005

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Nonracemic Homopropargylic Alcohols via Asymmetric Allenylboration with the Robust and Versatile 10‐TMS‐9‐Borabicyclo[3.3.2]decanes.
Authors: Lai Chunqiu , Soderquist John A.
Published: June 2005

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Asymmetric Synthesis of Aryloxypropanolamines via OsO4‐Catalyzed Asymmetric Dihydroxylation.
Authors: Sayyed Iliyas A. , Thakur Vinay V. , Nikalje Milind D. , Dewkar Gajanan K. , Kotkar S. P. , Sudalai A.
Published: June 2005

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Synthesis of Propargyl Ethers of Dihalogenalkanols
Authors: Bagirov R. R. , Talybov G. M. , Askerov M. E. , Karaev S. F.
Published: June 2005

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Asymmetric Synthesis of 3‐Methylthio Alcohols by Intramolecular Michael Addition Reactions.
Authors: Ortiz Aurelio , Hernandez Hector , Mendoza Guadalupe , Quintero Leticia , Bernes Sylvain
Published: June 2005

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Sulfur Dioxide Mediated Syntheses of Polyfunctional Alkenes and (E,Z)‐ and (E,E)‐2,4‐Dien‐1‐ones.
Authors: Bouchez Laure C. , Craita Cotinica , Vogel Pierre
Published: June 2005

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Copper‐Free Palladium‐Catalyzed Sonogashira‐Type Coupling of Aryl Halides and 1‐Aryl‐2‐(trimethylsilyl)acetylenes.
Authors: Soerensen Ulrik S. , Pombo‐Villar Esteban
Published: June 2005

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Synthesis of Functionalized m‐Bistrifluoromethylbenzenes via Cyclocondensation of 1,1,1,5,5,5‐Hexafluoroacetylacetone with Enamines.
Authors: Volochnyuk Dmitriy M. , Kostyuk Alexander N. , Sibgatulin Dmitriy A. , Chernega Alexander N.
Published: June 2005

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The Selective C‐3 Opening of Aromatic 2,3‐Epoxy Alcohols/Epoxides with Aromatic Amines Catalyzed by β‐Cyclodextrin in Water.
Authors: Surendra K. , Krishnaveni N. Srilakshmi , Rao K. Rama
Published: June 2005

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Ruthenium‐Catalyzed Coupling of Aldimines with Arylboronates: New Synthetic Method for Aromatic Ketones.
Authors: Park Young Jun , Jo Eun‐Ae , Jun Chul‐Ho
Published: June 2005

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