bluuebunny/crossref_metadata_2025 huggingface dataset:
Suppression of RelB-mediated manganese superoxide dismutase expression reveals a primary mechanism for radiosensitization effect of 1α,25-dihydroxyvitamin D3 in prostate cancer cells
Authors: Xu Yong , Fang Fang , St. Clair Daret K. , Josson Sajni , Sompol Pradoldej , Spasojevic Ivan , St. Clair William H.
Published: June 2007

Nuclear factor-κB provides an adaptive response to protect cancer cells against cytotoxicity induced by redox active therapeutics. RelB is uniquely expressed at a high level in prostate cancer with high Gleason scores. Recently, we showed that the level of RelB rapidly increases in androgen-independent prostate cancer cells after exposure to ionizing radiation (IR), leading to a reduction in intrinsic radiosensitivity. Here, we show that interaction of 1α,25-dihydroxyvitamin D3 [1α,25-(OH)2D3] with the vitamin D receptor significantly enhances radiosensitivity of prostate cancer cells at clinically relevant radiation doses. The radiosensitization effect of 1α,25-(OH)2D3 is mediated, at least in part, by selectively suppressing IR-mediated RelB activation, leading to a reduced expression of its target gene MnSOD, a primary antioxidant enzyme in mitochondria. These results suggest that suppression of manganese superoxide dismutase is a mechanism by which 1α,25-(OH)2D3 exerts its radiosensitization effect and that 1α,25-(OH)2D3 may serve as an effective pharmacologic agent for selectively sensitizing prostate cancer cells to IR via suppression of antioxidant responses in mitochondria. [Mol Cancer Ther 2007;6(7):2048–56]
Platelet-derived growth factor receptor-α: a novel therapeutic target in human hepatocellular cancer
Authors: Stock Peggy , Monga Dulabh , Tan Xinping , Micsenyi Amanda , Loizos Nick , Monga Satdarshan P.S.
Published: June 2007

Hepatocellular cancer (HCC) is a disease of poor prognosis. Identifying novel molecular aberrations might present opportunities to identify new therapeutic targets. Due to the similarities between the processes of development and cancer, we used early developing livers to identify genes that might play a primary role in HCC. Platelet-derived growth factor receptor-α (PDGFRα) was identified from microarray using early developing mouse livers. Expression of PDGFRα and its upstream effectors, PDGF-AA and PDGF-CC, were examined in HCC tissues (n = 43) by Western blot, real-time PCR, and immunohistochemistry. Finally, effect of anti-PDGFRα antibody (mAb 3G3, ImClone Systems, Inc.) was examined on human hepatoma cells. A high expression of PDGFRα was observed during early liver development. HCCs (17 of 21) revealed cytoplasmic PDGFRα and activated PDGFRα (phospho-Tyr754) by immunohistochemistry. Additional HCCs (14 of 22) showed elevated PDGFRα levels when compared with the adjacent normal livers by Western blots. Of these 14 patients, 3 showed increased PDGFRα gene expression, 3 showed elevated PDGF-AA, and 4 had higher PDGF-CC levels in the tumors compared with adjacent livers. Multiple hepatoma cell lines, when treated with mAb 3G3, showed significant decreases in cell proliferation and survival (P < 0.05). In conclusion, ∼70% of HCC tissues had elevated PDGFRα levels due to diverse mechanisms. PDGFRα inhibition in hepatoma cells led to diminution of tumor cell survival and proliferation and thus might be of therapeutic significance. [Mol Cancer Ther 2007;6(7):1932–41]
The alkylphospholipid perifosine induces apoptosis of human lung cancer cells requiring inhibition of Akt and activation of the extrinsic apoptotic pathway
Authors: Elrod Heath A. , Lin Yi-Dan , Yue Ping , Wang Xuerong , Lonial Sagar , Khuri Fadlo R. , Sun Shi-Yong
Published: June 2007

The Akt inhibitor, perifosine, is an alkylphospholipid exhibiting antitumor properties and is currently in phase II clinical trials for various types of cancer. The mechanisms by which perifosine exerts its antitumor effects, including the induction of apoptosis, are not well understood. The current study focused on the effects of perifosine on the induction of apoptosis and its underlying mechanisms in human non–small cell lung cancer (NSCLC) cells. Perifosine, at clinically achievable concentration ranges of 10 to 15 μmol/L, effectively inhibited the growth and induced apoptosis of NSCLC cells. Perifosine inhibited Akt phosphorylation and reduced the levels of total Akt. Importantly, enforced activation of Akt attenuated perifosine-induced apoptosis. These results indicate that Akt inhibition is necessary for perifosine-induced apoptosis. Despite the activation of both caspase-8 and caspase-9, perifosine strikingly induced the expression of the tumor necrosis factor–related apoptosis-inducing ligand (TRAIL) receptor, death receptor 5, and down-regulated cellular FLICE-inhibitory protein (c-FLIP), an endogenous inhibitor of the extrinsic apoptotic pathway, with limited modulatory effects on the expression of other genes including Bcl-2, Bcl-XL, PUMA, and survivin. Silencing of either caspase-8 or death receptor 5 attenuated perifosine-induced apoptosis. Consistently, further down-regulation of c-FLIP expression with c-FLIP small interfering RNA sensitized cells to perifosine-induced apoptosis, whereas enforced overexpression of ectopic c-FLIP conferred resistance to perifosine. Collectively, these data indicate that activation of the extrinsic apoptotic pathway plays a critical role in perifosine-induced apoptosis. Moreover, perifosine cooperates with TRAIL to enhance the induction of apoptosis in human NSCLC cells, thus warranting future in vivo and clinical evaluation of perifosine in combination with TRAIL in the treatment of NSCLC. [Mol Cancer Ther 2007;6(7):2029–38]
The "Commentary" That Saved the Text. The Hazardous Journey of Ibn al-Haytham's Arabic Optics
Authors: Sabra
Published: June 2007

The "Text" and the "Commentary" mentioned in the title of this essay are, respectively, the Kitāb al-Manāzir, or Optics, of al-Hasan ibn al-Haytham, composed in the first half of the fifth/eleventh century, and the Tanqīh al-Manāzir li-dhawī l-absār wa l-basā'ir, written by Abū l-Hasan (or al-Hasan) Kamāl al-Dīn al-Fārisī in the second half of the seventh/thirteenth century. It is known that, so far, only the first five of the seven maqālāt /Books that make up the Arabic text of IH's Optics have been published, and that the Tanqīh was published in two volumes. I shall be concerned with certain episodes in the lives of these two works, my aim being to shed light on their transmission within the Islamic Arabic and Persian worlds.
Traduire Linné en français à la fin du XVIIIe siècle
Authors: Duris Pascal
Published: June 2007

The Swedish naturalist Carl von Linné (1707-1778) wrote his entire scientific œuvre in Latin. Because of both the rarity and costliness of his books and the decline of Latin as the language of science in France, Linnæus' partisans tried from 1780 onwards to translate his major works into French. Quesné's integral translation of the Philosophia botanica of 1788 is characteristic of this attempt. But this enterprise encountered major difficulties, as some translators proposed a wholesale 'Frenchisation' of the Latin terminology, while others preferred to explicate Linnæus' terse style by means of paraphrases and commentaries. The origin of the problem resides in the fact that Linnæus had created a new language at once to describe and to name living beings. The translators' dilemma was also one of readership : were their translations to be used by experts or rather as pedagogical tools by learners?
Poetry or Pathology? Jesuit Hypochondria in Early Modern Naples
Authors: Haskell Yasmin
Published: June 2007

In their didactic poems on fishing and chocolate, both published in 1689, two Neapolitan Jesuits digressed to record and lament a devastating 'plague' of 'hypochondria'. The poetic plagues of Niccolò Giannettasio and Tommaso Strozzi have literary precedents in Lucretius, Vergil, and Fracastoro, but it will be argued that they also have a real, contemporary significance. Hypochondria was considered to be a serious (and epidemic) illness in the seventeenth century, with symptoms ranging from depression to delusions. Not only did our Jesuit poets claim to have suffered from it, but so did prominent members of the 'Accademia degl'Investiganti', a scientific society in Naples that was at odds with both the religious and medical establishments.
The Relationship Between an Effective Organizational Culture and Student Discipline in a Boarding School
Authors: van der Westhuizen Philip C. , Oosthuizen Izak , Wolhuter C.C.
Published: June 2007

This article investigates the relationship between effective organizational culture and student discipline in a boys' boarding house at an urban South African school. Ethnographical methods (observation and interviews) were employed. The study reports on the results pertaining to organizational culture, namely, tangible manifestations of the organizational culture, that is, traditions, ceremonies, symbols, and the external and internal appearance of the boarding house. It also reports on the intangible manifestations, that is, students' and teachers' beliefs and the mission, vision, values, and norms of the boarding house itself. In conclusion, an explanation is tendered for the positive relationship that can be shown to exist between the organizational culture and learner discipline.
Marketing Schools
Authors: Lubienski Christopher
Published: June 2007

Effective school-choice plans depend on the quality of information available to families. Examining the promotional materials provided by different schools in a highly competitive and diverse urban area tells us not only about the quality of that information but also how schools respond to competitive incentives. This analysis outlines an economic theory of goods as a framework for understanding information, focusing on the essential “search,” “experience,” and “credence” qualities of promotional materials. The information made available to families through commercial-style materials challenges the notion of parents making reasoned choices based on institutional effectiveness. Instead, more emotional themes and images dominate school marketing strategies, with implications for ethnic and socioeconomic sorting within diverse but competitive climates. Promotional strategies suggest that competition is creating an environment in which, rather than responding to incentives intended to improve education for more disadvantaged students, schools are instead attracting better performing students through their marketing campaigns.
Are Charter Schools Using Recruitment Strategies to Increase Student Body Diversity?
Authors: Eckes Suzanne E. , Trotter Anne E.
Published: June 2007

Depending on state statutory language, charter schools may be able to exercise more control over their student body composition. Unlike traditional public schools, charter schools may have the opportunity to increase student body diversity by drawing students from across traditional school district boundary lines. Specifically, depending on the state statutory language, charter schools may be permitted some flexibility in recruiting and admitting students. This study investigates the admissions and recruitment practices of eight high-achieving charter schools and considers whether charter school leaders negotiate state statutes to create a diverse student body.
A Meta-Analysis of the Relationship Between Phonics Instruction and Minority Elementary School Student Academic Achievement
Authors: Jeynes William H.
Published: June 2007

This meta-analysis of 22 studies examines the relationship between phonics and the academic achievement of urban minority elementary school children. Further analyses distinguish between those studies that are of higher quality than the others and those studies that examine all minority students and mostly minority students. Results indicate a significant relationship between phonics instruction and higher academic achievement. Phonics instruction, as a whole, is associated with academic variables by about .23 to .33 of a standard deviation unit. This relationship holds for studies that examine all minority students and those that include mostly minority students. The results also hold for higher quality studies. The significance of these results is discussed.
Roles and Responsibilities of Adapted Physical Education Teachers in an Urban School District
Authors: Akuffo Patrick B. , Hodge Samuel R.
Published: June 2007

The purpose of this study is to examine the roles and responsibilities of itinerant adapted physical education (APE) teachers at urban public schools. A second purpose is to determine how they execute their roles and responsibilities. Participants include six women with experience as itinerant APE teachers from the same urban school district. The research method is exploratory multiple-case study. Data are collected from focused interviews and on-site observations. Constant comparative procedures are used for within-case and cross-case analyses. Several themes emerge from the data. These themes are (a) teaching as obligatory, (b) self-reliant, and (c) teaching effectiveness relative and contextually situated. Gaining a better understanding of the experiences of practicing APE teachers in urban public schools who teach a diversity of students is important to the preparation of future teachers.
Personal Epistemology of Urban Elementary School Teachers
Authors: Pearrow Melissa , Sanchez William
Published: June 2007

Personal epistemology, originating from social construction theory, provides a framework for researchers to understand how individuals view their world. The Attitudes About Reality (AAR) scale is one survey method that qualitatively assesses personal epistemology along the logical positivist and social constructionist continuum; however, the literature primarily reflects women working in a mental health facility and undergraduate students. This study uses the AAR to examine the personal epistemology of 73 elementary school teachers, the large majority of whom were female, working in an urban and highly diverse public school system in the Northeast, and compares the AAR score to demographic data. The results suggest a more logical positivist orientation than has been observed with other populations although demographic information did not assist in understanding the findings. Implications for the urban elementary school environment, classroom interventions, and collaboration with other support professionals are offered.
Habit Formation and Multiple Means to Goal Attainment: Repeated Retrieval of Target Means Causes Inhibited Access to Competitors
Authors: Danner Unna N. , Aarts Henk , de Vries Nanne K.
Published: June 2007

Three studies examined the cognitive processes underlying the formation of goal-directed habits in a multiple means context. Repeated retrieval of target means upon goal activation was expected to result in inhibition of competing means for the same goal. In all studies, participants studied goal—means combinations and subsequently practiced the retrieval of certain means to attain the goals in a retrieval paradigm. Study 1 tested accessibility of the different means in a goal—means verification task and showed that competing means were not inhibited after a single retrieval but only upon repeated retrieval (three or nine times). Studies 2 and 3 extended these findings in a means—recognition task and demonstrated that inhibition occurred in the absence of explicit intent or instructions to suppress the competitors. These inhibitory effects of competing means are discussed against the background of current social cognition research on the processes underlying goal—means networks and the formation of habits.
From Cure to Palliation: Agreement, Timing, and Decision Making Within the Staff
Authors: Agren Bolmsjö Ingrid , Nilstun Tore , LöFmark Rurik
Published: June 2007

Important issues in the transition From curative treatment to palliative care are agreement, timing, and decision making. A survey oF 309 nurses and 415 physicians in Sweden showed that 61% oF the nurses and 83% oF the physicians thought agreement was current practice. None said that the decisions were made too early, but 19% oF the nurses and 14% oF the physicians thought that they oFten were made too late. Very Few respondents stated that such decisions are changed, 0% and 1%, respectively. More than halF oF the inFormants made detailed comments on such transitions indicating that awareness and Flexibility are desirable to make well-inFormed decisions. Three themes that emerged From the analysis concerning the decision to stop curative treatment and Focus on palliative care were that the staFF members should (iF possible) make such decisions in agreement and should sometimes make the decisions earlier and that well-based reasons are required to make changes.
What About the Trach? Tracheotomy Removal as a Palliative Care Maneuver
Authors: Newman Alfred J. , Kvale Elizabeth A. , Williams Beverly R. , Bailey F. Amos
Published: June 2007

Tracheotomy is performed on patients with airway obstruction or prolonged mechanical ventilation. Tracheotomy patients are increasingly being referred to hospice and palliative care. This case series describes a process for evaluating the ongoing need for tracheotomy and the impact of tracheotomy removal. A retrospective cohort design was used in which charts were reviewed of all tracheotomy patients referred to the palliative care unit between November 1, 1998, and July 31, 2001. Tracheotomy was present in 13 of 791 palliative care unit admissions. Persistent airway obstruction contraindicated tracheotomy removal in 5 patients. The remaining patients had a successful “button” trial with subsequent tracheotomy removal. They incurred no complications and exhibited improved functional status and decreased symptom burden. Tracheotomy removal is safe and beneficial in this patient subset and should be considered an alternative to prolonged tracheotomy.
Physician and Nurse Attitudes Toward Artificial Hydration for Terminally Ill Cancer Patients in Japan: Results of 2 Nationwide Surveys
Authors: Miyashita Mitsunori , Morita Tatsuya , Shima Yasuo , Kimura Rieko , Takahashi Mikako , Adachi Isamu
Published: June 2007

This study investigated physician and nurse attitudes toward artificial hydration in terminally ill cancer patients and compared differences in attitudes between these 2 professions and among clinical settings in Japan. The response rate was 53% (584/1123) for physicians and 79% for nurses (3328/4210). More physicians answered that artificial hydration alleviates the sensation of thirst. More palliative care unit physicians and nurses answered that withholding artificial hydration alleviated several physical symptoms. Oncologists answered that artificial hydration alleviated the sensation of thirst and fatigue. Discussion among patient-centered teams and individualized decision making are important. Because the differences identified here are attributable to differences in knowledge of artificial hydration for terminal cancer patients, oncologists should place greater emphasis on the opinion of palliative care specialists. Medical practitioners caring for terminal cancer patients should consider a broader range of views on hydration therapy, with a focus on effective hydration techniques and alternative interventions.
The Importance of Perspective: Evaluation of Hospice Care From Multiple Stakeholders
Authors: Hiatt Kelly , Stelle Charlie , Mulsow Miriam , Pearson Scott Jean
Published: June 2007

The literature on hospice care and palliative medicine lacks a focus on the combined and concurrent assessment of services. This deficiency is problematic because research findings are then limited in their scope and applicability to particular stakeholder groups. The current study used the perspective of 72 participants and service delivery personnel of a home-based hospice program to address this perceived problem and limitation in the literature through a program evaluation of the multiple perspectives on a single hospice organization. Interviews were analyzed by stakeholder group and then across stakeholder groups to extract themes. Results include a description of the quality of service delivery and participant satisfaction, areas of current weakness, and ideas for potential growth and development for the program. Findings from this study are compared with previous research on hospice care and the implications of the results to the provision and continued development of hospice care are discussed.
Nurse Views of the Adequacy of Decision Making and Nurse Distress Regarding Artificial Hydration for Terminally Ill Cancer Patients: A Nationwide Survey
Authors: Miyashita Mitsunori , Morita Tatsuya , Shima Yasuo , Kimura Rieko , Takahashi Mikako , Adachi Isamu
Published: June 2007

We evaluated nurse views on the adequacy of decision-making discussion among nurses and physicians regarding artificial hydration for terminally ill cancer patients and nurse distress arising from artificial hydration issues, as well as factors related to this distress. A self-administered questionnaire consisting of 4 questions about nurse views of discussions regarding artificial hydration and 6 questions about nurse distress arising from artificial hydration issues was distributed in participating institutions in October 2002 and returned by mail. A total of 3328 responses (79%) were analyzed. Almost half of the nurses felt that discussion of terminal hydration issues was insufficient. Among responses, 39% of oncology nurses and 78% of palliative care unit (PCU) nurses agreed that patients and medical practitioners discuss the issue of artificial hydration adequately, and 49% and 79%, respectively, agreed that medical practitioners discuss the issue of artificial hydration with other physicians adequately. As for distress on behalf of patients and families who refuse artificial hydration, 44% of oncology nurses and 57% of PCU nurses experienced such distress for patients, and 19% and 28% did so for families, respectively. Furthermore, 48% of oncology nurses and 47% of PCU nurses experienced distress arising from disagreements among medical practitioners about withholding artificial hydration, whereas 44% and 43% experienced distress about medical practitioners refusing artificial hydration, respectively. Discussion among care providers regarding artificial hydration is insufficient, particularly in general wards. Medical practitioners caring for terminally ill cancer patients should engage in greater discussion among patient-centered teams and facilitate individualized decision making.
Are there Racial Differences in Attitudes Toward Hospice Care? A Study of Hospice-Eligible Patients at the Visiting Nurse Service of New York
Authors: Rosenfeld Peri , Dennis Jeanne , Hanen Suzanne , Henriquez Ernesto , Schwartz Theresa M. , Correoso Lyla , Murtaugh Christopher M. , Fleishman Alan
Published: June 2007

Research on African American and white attitudes, perceptions, and knowledge of hospice care has focused predominantly on patients and providers in institutions and community-based care settings. Little is known about patients receiving home health services, despite growing trends toward noninstitutional care in the United States. This study of home health clients who are eligible for hospice, but not currently receiving it, found few differences between racial groups with regard to attitudes about end-of-life care. An alarming proportion of African American and white home health clients held erroneous ideas about hospice care and had not discussed this option with their providers. These findings suggest that increased referrals to home-based hospice care among home health clients depend on the availability and professional dissemination of accurate, spiritually sensitive information.
Developing and Validating a Measure of Chinese Cultural Views of Health and Cancer
Authors: Wenchi Liang  , Wang Judy H. , Chen Mei-Yuh , Shibao Feng  , Lee Marion , Schwartz Marc D. , Pasick Rena J. , Mandelblatt Jeanne S.
Published: June 2007

To develop and validate quantitative scales that measure Chinese cultural views about health and cancer, cultural views were assessed by a 30-item scale through telephone interviews with 438 Chinese-American women aged 50 and older. Cultural subscales were identified using principal component analysis and validated by their associations with age at immigration and breast, cervical, and colorectal cancer (CRC) screening patterns. The overall scale had good reliability (Cronbach's alpha = .79). Factor analysis yielded seven cultural subscales—fatalism, hot-cold balance, use of herbs, self-care, medical examination, lifestyle, and Western medicine (alpha = .39 to .82). The majority of the cultural subscales were significantly associated with age at immigration ( p < .001). Fatalism, Self-Care, and Medical Examination subscales consistently predicted nonadherence to breast, cervical, and CRC screening recommendations, even after considering other factors. Chinese cultural views consist of at least seven domains and may influence older women's breast, cervical, and CRC screening.
Development and Evaluation of a Culturally Tailored Educational Video: Changing Breast Cancer–Related Behaviors in Chinese Women
Authors: Wang Judy H. , Liang Wenchi , Schwartz Marc D. , Lee Marion M. , Kreling Barbara , Mandelblatt Jeanne S.
Published: June 2007

This study developed and evaluated a culturally tailored video guided by the health belief model to improve Chinese women's low rate of mammography use. Focus-group discussions and an advisory board meeting guided the video development. A 17-min video, including a soap opera and physician-recommendation segment, was made in Chinese languages. A pretest/posttest pilot was conducted to evaluate the efficacy of the video in changing knowledge, beliefs, and screening intentions among Chinese women (age ≥ 40) who were nonadherent to current National Cancer Institute's mammography guidelines ( n = 52). The results showed that the video significantly increased these women's screening intentions, knowledge, perceived risk for breast cancer, and perceived benefits of mammography. Chinese immigrant women were less likely to hold an Eastern view of health care and report barriers to screening after viewing the video. This video might have the potential to increase adherence to mammography screening in Chinese women.
Identifying Opinion Leaders to Promote Behavior Change
Authors: Valente Thomas W. , Pumpuang Patchareeya
Published: June 2007

This article reviews 10 techniques used to identify opinion leaders to promote behavior change. Opinion leaders can act as gatekeepers for interventions, help change social norms, and accelerate behavior change. Few studies document the manner in which opinion leaders are identified, recruited, and trained to promote health. The authors categorize close to 200 studies that have studied or used opinion leaders to promote behavior change into 10 different methods. They present the advantages and disadvantages of the 10 opinion leader identification methods and provide sample instruments for each. Factors that might influence programs to select one or another method are then discussed, and the article closes with a discussion of combining and comparing methods.
Mass Media for Smoking Cessation in Adolescents
Authors: Solomon Laura J. , Bunn Janice Y. , Flynn Brian S. , Pirie Phyllis L. , Worden John K. , Ashikaga Takamaru
Published: June 2007

Theory-driven, mass media interventions prevent smoking among youth. This study examined effects of a media campaign on adolescent smoking cessation. Four matched pairs of media markets in four states were randomized to receive or not receive a 3-year television/radio campaign aimed at adolescent smoking cessation based on social cognitive theory. The authors enrolled 2,030 adolescent smokers into the cohort ( n = 987 experimental; n = 1,043 comparison) and assessed them via annual telephone surveys for 3 years. Although the condition by time interaction was not significant, the proportion of adolescents smoking in the past month was significantly lower in the experimental than comparison condition at 3-year follow-up when adjusted for baseline smoking status. The media campaign did not impact targeted mediating variables. A media campaign based on social cognitive constructs produced a modest overall effect on smoking prevalence among adolescents, but the role of theory-based constructs is unclear.
Osteoporosis Health Beliefs Among Younger and Older Men and Women
Authors: Shanthi Johnson C. , McLeod William , Kennedy Laura , McLeod Katherine
Published: June 2007

The purpose of this study was to compare osteoporosis health beliefs among different age and gender groups. This study used a cross-sectional design, involved 300 participants that represent both genders and three age groups (18 to 25, 30 to 50, and 50-plus), and assessed osteoporosis health beliefs using the Osteoporosis Health Belief Scale (OHBS). Factor analysis revealed three subscales of OHBS: perceived susceptibility, seriousness of the condition, and health motivation to take preventative actions with acceptable levels of reliability. Significant age and gender differences were observed in the susceptibility scores of the OHBS. The perceived seriousness of the osteoporosis scores was similar across all age and gender groups, as was health motivation. These results highlight the need for osteoporosis awareness programs targeting different aspects of belief perceptions, specifically for younger women and men.
Superplastic deformation behaviour of electrodeposited nanocrystalline nickel
Authors: Chan K. C. , Wang C. L. , Zhang K. F.
Published: June 2007

In this paper, the superplasticity of an electrodeposited nanocrystalline nickel with a grain size of 65 nm was examined under different strain rates and temperatures. A maximum elongation of 550% was obtained at a relatively low temperature of 450°C and a strain rate of 1·67 × 10−3 s−1. The strain rate sensitivity index is found to be >0·5 demonstrating its good superplasticity. The fracture surfaces and the deformed microstructures reveal that significant grain growth occurs during deformation, and it is found that the addition of SiC particles can effectively improve the superplasticity of the material. Experimental results further illustrate that the deformed microstructure is dependent on the strain rate, and the surface morphology of the material is relating to its oxidation phenomenon during deformation.
Preparation and characterisation of electroformed Cu/nano Al2O3 composite
Authors: Zhu J. H. , Liu H. Z. , Liu L. , Zhao H. J. , Shen B. , Hu W. B.
Published: June 2007

The composite electroforming technology was used to fabricate nanosized alumina particles (nano Al2O3) reinforced copper matrix composite. The surface, fracture and wear surface morphology were observed by scanning electron microscopy (SEM) as well as microstructure observed by transmission electron microscopy (TEM). Microhardness, tensile properties, wear resistance and electrical resistivity Er were investigated. The results showed that Cu/nano Al2O3 composites with different compositions were obtained successfully by composite electroforming technology. Nano Al2O3 particles were dispersed in copper matrix uniformly and tightly. By comparing with the electroformed pure copper, Cu/nano Al2O3 composites achieved higher microhardness, better mechanical property and wear resistance, and just a little effect of nano Al2O3 on the electrical property of composite was presented.
Determination of sizing conditions for E class glass fibre yarn using Taguchi parameter design
Authors: Cheng J.-C. , Lai W.-T. , Chou C.-Y. , Lin H.-H.
Published: June 2007

E class glass fibre has attributes of high strength, non-electric conduction, light weight and high temperature resistant, which especially make it suitable for electronic applications. Good sizing conditions will strengthen the glass fibre yarn, reduce the number of broken filaments, and speed up the weaving process. However, in the literature, little attention has been devoted to study of determining the appropriate sizing conditions. Parameter design, introduced by Taguchi, has been shown to be an effective approach for improving quality and productivity at low cost. The present paper reports a case study on application of parameter design to determining the optimal sizing conditions for E class glass fibre yarn such that the number of fuzzes of each filament can be reduced and the frequency of rub resistance of each filament may be enhanced. The modified L16 orthogonal array, the smaller the better and larger the better signal to noise ratios and the analysis of variance are employed to carry out the bivariate parameter design and its corresponding data analysis. Through this study, not only can the optimal sizing conditions for the E class glass fibre yarn be obtained, but also the significant factors that affect the number of fuzzes and the frequency of rub resistance of each filament can be found. Experimental results are provided to confirm the effectiveness of this approach.
A review of laser fabrication of metallic engineering components and of materials
Authors: Wu X.
Published: June 2007

The state of the art and directions for the future development of two laser based technologies, direct laser fabrication in which powder is fed into the focal point of a laser, and a laser powder bed technology are outlined in this review. The areas in which these technologies have made significant contributions are: the manufacture, directly from powder, of alloys and of functionally graded materials which enables a range of compositions to be assessed rapidly and the manufacture of net shape and the repair of engineering components. It is suggested that rapid assessment of structure/property relationships in a range of compositions will continue to be a useful application of laser fabrication. It is further concluded that the two approaches, direct laser fabrication and laser powder bed will continue to be developed since each has its own advantages and disadvantages; direct laser fabrication is the preferred technique for alloy development work and for component repair but laser bed technology is currently the preferred technology for the manufacture of small components which require a good surface finish. Improvements in surface finish, in dimensional accuracy, in microstructural control and in process control with real time feedback to control properties are nevertheless required if these technologies are to increase their impact in the area of the manufacture of net shape components.
Microstructure and mechanical performance of GTA weld brazed joints of copper thick plates
Authors: Yan J. C. , Li Y. N. , Liu X. S. , Zhang Y. , Yu H. C. , Yang S. Q.
Published: June 2007

The gas tungsten arc (GTA) weld brazing of 10 mm copper thick plates without preheating was investigated. The filler metal of Cu–Ag–P eutectic alloy was used in the experiments. The GTA weld brazing and brazing were compared on the microstructure and mechanical performance of their joints. It can be found that the base metal is largely dissolved by the filler metal in the case of infusion of the copper, and the α-Cu solid solution in the weld metal for weld brazing is larger than that in the weld metal for brazing. The average hardness of the weld metal for weld brazing is 50 HV lower than that for brazing. The impact ductility for weld brazing is almost thrice of that for brazing.
Aluminium powder particles produced by SAMD technique: Typical characteristics and correlations between processing conditions and powder size
Authors: Akhlaghi F. , Esfandiari H.
Published: June 2007

The present paper consists of two parts. In the first part the principles of a new method of metal powder production, termed ‘solid assisted melt disintegration (SAMD)’ are discussed and the typical characteristics of the produced powder are outlined. In the second part the effects of some processing parameters on the size distribution and mean diameter of the powder are reported. The SAMD method involves mixing solid particles (i.e. alumina) with the liquid aluminium alloy aided by mechanical agitation. The shear force induced by the impeller is transferred to the metal via the non-wetting solid medium and results in melt disintegration. The resulting mixture of aluminium droplets and alumina particles are subsequently cooled in air and screened through 300 μm sieve to separate alumina from solidified aluminium powder particles. The SAMD technique has demonstrated the capability to produce a wide particle size distribution. The small sized particles (i.e. <53 μm) exhibited irregular shapes, but larger ones were mostly spherical. These powder particles were dense (pore free) without attached satellite particles and exhibited a relatively coarse microstructure. The processing parameters investigated include the size of Al2O3 particles, Al2O3/Al weight ratio, stirring speed and stirring time. It was concluded that there exists an optimum value for each of the aforementioned parameters corresponding to a minimum in the mean particle size.
Synthesis of β-FeOOH with microemulsion
Authors: Yang Y. X. , Liu X. N. , Zhu H. , Huang Z. , Chen Y. R. , Zhou Z. Y.
Published: June 2007

β-FeOOH particles were prepared by forced hydrolysis of FeCl3·6H2O in microemulsion containing polyoxyethylene nonylphenylether (NP-4), octane and water. The samples were characterised using XRD and TEM. The effects of the molar ratio of water to NP-4 R, initial Fe3+ concentration and pH of the system on the morphology and size of the nanoparticles are discussed. The results show that the acidity and size of ‘water pool’ and the initial Fe3+ concentration are the main factors that affect the morphology of β-FeOOH particles. It is found that the optimum conditions for synthesising acicular β-FeOOH is R=6·0, [Fe3+]=0·02 mol L−1 within the pH range 1·6–2·0. The crystal structure of as synthesised acicular β-FeOOH belongs to the monoclinic system with lattice parameters a=0·9981 nm, b=0·2948 nm, c=1·0485 nm, β=92·26°.
Calculation of apparent resistivity of metallic open cell foams by dodecahedron model
Authors: Duan D. L. , Li S. , Zhang R. L. , Jiang S. L.
Published: June 2007

A pentagonal dodecahedron (PD) model based on the interconnected beam structure of open celled foam was considered for calculation of apparent resistivity of metallic foams. According to the PD model, the mathematical relationship between apparent resistivity and structure parameters (cell size, length or thickness of cell wall) of metallic foams was derived. The mathematical equation showed that the apparent resistivity increased with the resistivity of the compact metals and the porosity of metallic foams. In addition, the calculated evaluations were proved to be in approximate agreement with experimental results of Ni–Cr foams and Ni foams.
3D finite element analysis on strain uniformity during ECAP process
Authors: Su C. W. , Lu L. , Lai M. O.
Published: June 2007

The uniformity of plastic strain distribution in a workpiece after equal channel angular pressing (ECAP) was studied using finite element software ABAQUS in 3D. Processing parameters including the channel intersection angle Φ, channel outer curvature Ψ, pressing speed, friction and processing route were varied to study their effects on strain homogeneity. It was found that a single ECAP pass was unable to produce homogenous strains in a workpiece although strain distribution can be improved by selecting the appropriate processing parameters. Multiple ECAP passes improved strain homogeneity significantly.
Investigations on role of plasma sprayed NiCrAlY and Ni–20Cr coatings to combat hot corrosion
Authors: Singh H. , Puri D. , Prakash S. , Hira D. S.
Published: June 2007

Studies have been conducted to ascertain the role of plasma sprayed Ni–20Cr–10Al–1Y (NiCrAlY) and Ni–20Cr metallic coatings to combat hot corrosion of a Ni based superalloy Superni 75 (Ni–3Fe–19·5Cr–0·3Ti–0·1C). The performance of the uncoated as well as coated superalloy has been evaluated in an aggressive environment of Na2SO4–60%V2O5 under cyclic conditions at an elevated temperature of 900°C by the thermogravimetric technique for 50 cycles. X-ray diffraction (XRD), SEM/EDAX and electro probe microanalysis (EPMA) techniques were used to analyse the corrosion products. The uncoated superalloy suffered an accelerated oxidation in the form of spalling of its oxide scale, whereas NiCrAlY coated specimen showed marginal spalling towards the end of exposure. The Ni–20Cr coated superalloys did not suffer from spallation of its oxide scale. The Ni–20Cr coated specimen indicated a maximum weight gain among the cases studied, while NiCrAlY coated the least. Both the coatings were found to be useful in protecting the base superalloy against oxidation. Moreover the coatings, in general were successful in maintaining their continuous surface contact with the substrate superalloy during the whole tenure of cyclic exposure. The phases revealed for the oxidised coatings were mainly oxides of chromium/aluminium, and spinel containing nickel–chromium mixed oxides, which are reported to be protective against the hot corrosion.
Fundamental study on microstructure and physical properties of fluidised bed and rainfall sanding ceramic shells
Authors: Jones S. , Yuan C. , Blackburn S.
Published: June 2007

The investment casting technique has advantages in the production of quality components and key benefits of accuracy, versatility and integrity. The mechanical performance of the ceramic shell is fundamental to the quality of the finished component. Two main techniques are used in the casting industry for the application of stucco material: rainfall sanding and fluidised bed. Work was carried out to characterise the fundamental difference in physical structure and mechanical properties of shells produced by both techniques. Stucco application within samples prepared by fluidised bed showed a tendency for the particles to be parallel to the ceramic surface, while in samples prepared by rainfall sanding the particles were more random and embedded into the slurry layer resulting in a thinner total shell build. Stress–strain curves generated form fired samples prepared by fluidised bed demonstrated a certain degree of non-brittle fracture, where this is not the case for rainfall sanding produced material. It is suggested that this is related to the manner in which cracks propagate through in the fluidised bed structure during testing. A relatively larger proportion of through stucco fracture was found in rainfall sanding produced samples in comparison to that in fluidised bed produced samples.
Microstructural characterisation of several magnesium alloys in AM series
Authors: Wei L.-Y. , Warren R.
Published: June 2007

The as cast microstructures of several magnesium alloys in the AM series have been characterised, including the dendritic structure, Al segregation and the Mn containing phases. Two types of Mn containing particles were found and studied in the alloys mainly by using TEM. Type I is of equiaxed morphologies and a higher Mn/Al ratio in the composition. The flower shaped and dendritic type II phase has a lower Mn/Al ratio. The equiaxed type I could originate in the particle residues in the melts retained in the as cast alloy and the type II might form around a small type I particle. Electron diffraction has determined that both type I and type II have bcc crystal structure with lattice parameter a=0·91 nm. The higher Mn content in an alloy may lead to a higher amount of Mn containing particles.
Leukemia stem cells in a genetically defined murine model of blast-crisis CML
Authors: Neering Sarah J. , Bushnell Timothy , Sozer Selcuk , Ashton John , Rossi Randall M. , Wang Pin-Yi , Bell Deborah R. , Heinrich David , Bottaro Andrea , Jordan Craig T.
Published: June 2007

Myeloid leukemia arises from leukemia stem cells (LSCs), which are resistant to standard chemotherapy agents and likely to be a major cause of drug-resistant disease and relapse. To investigate the in vivo properties of LSCs, we developed a mouse model in which the biologic features of human LSCs are closely mimicked. Primitive normal hematopoietic cells were modified to express the BCR/ABL and Nup98/HoxA9 translocation products, and a distinct LSC population, with the aberrant immunophenotype of lineage−, Kit+/−, Flt3+, Sca+, CD34+, and CD150−, was identified. In vivo studies were then performed to assess the response of LSCs to therapeutic insult. Treatment of animals with the ABL kinase inhibitor imatinib mesylate induced specific modulation of blasts and progenitor cells but not stem- cell populations, thereby recapitulating events inferred to occur in human chronic myelogenous leukemia (CML) patients. In addition, challenge of leukemic mice with total body irradiation was selectively toxic to normal hematopoietic stem cells (HSCs), suggesting that LSCs are resistant to apoptosis and/or senescence in vivo. Taken together, the system provides a powerful means by which the in vivo behavior of LSCs versus HSCs can be characterized and candidate treatment regimens can be optimized for maximal specificity toward primitive leukemia cells.
Experimental concepts for toxicity prevention and tissue restoration after central nervous system irradiation
Authors: Nieder Carsten , Andratschke Nicolaus , Astner Sabrina T
Published: June 2007

Several experimental strategies of radiation-induced central nervous system toxicity prevention have recently resulted in encouraging data. The present review summarizes the background for this research and the treatment results. It extends to the perspectives of tissue regeneration strategies, based for example on stem and progenitor cells. Preliminary data suggest a scenario with individually tailored strategies where patients with certain types of comorbidity, resulting in impaired regeneration reserve capacity, might be considered for toxicity prevention, while others might be "salvaged" by delayed interventions that circumvent the problem of normal tissue specificity. Given the complexity of radiation-induced changes, single target interventions might not suffice. Future interventions might vary with patient age, elapsed time from radiotherapy and toxicity type. Potential components include several drugs that interact with neurodegeneration, cell transplantation (into the CNS itself, the blood stream, or both) and creation of reparative signals and a permissive microenvironment, e.g., for cell homing. Without manipulation of the stem cell niche either by cell transfection or addition of appropriate chemokines and growth factors and by providing normal perfusion of the affected region, durable success of such cell-based approaches is hard to imagine.