bluuebunny/crossref_metadata_2025 huggingface dataset:
Conversational Interaction and Second Language Development: Recasts, Responses, and Red Herrings?
Authors: MACKEY ALISON , PHILP JENEFER
Published: October 2011

This article examines the effects of negotiated interaction on the production and development of question forms in English as a second language (ESL). The study focused on one feature of interaction, recasts, which have recently been the topic of interactional work in the SLA literature (Long, 1996; Long, Inagaki, & Ortega, this issue; Lyster & Ranta, 1997; Oliver, 1995). The study compared groups of learners who received interactionally modified input with learners who received the same input containing intensive recasts in order to investigate: (a) the effect of recasts on learners' short term interlanguage (IL) development, and (b) the nature and content of learners' responses to recasts. The results suggest that for more advanced learners, interaction with intensive recasts may be more beneficial than interaction alone in facilitating an increase in production of targeted higher‐level morphosyntactic forms. These positive developmental effects were found for recasts even though, as is generally acknowledged in the discourse, recasts were usually not repeated and rarely elicited modification by the learners. This study, therefore, suggests that recasts may be beneficial for short term IL development even though they are not incorporated in learners' immediate responses. In fact, the responses may be red herrings.
Assessing Students' Oral Proficiency in an Outcome‐Based Curriculum: Student Performance and Teacher Intuitions
Authors: GLISAN EILEEN W. , FOLTZ DAVID A.
Published: October 2011

This article describes the results of a study conducted with two school districts in order to investigate (a) students' OPI ratings at the end of a typical 4‐year sequence of study, (b) the degree to which teachers could accurately predict their students' proficiency ratings, and (c) the relationship between classroom achievement and oral proficiency ratings. Findings indicate that (a) students at a given level of foreign language (FL) study demonstrate a range of OPI ratings; (b) a typical 4‐year sequence, for many students, is not sufficient time to attain Intermediate‐Low oral proficiency; (c) teachers need some type of OPI training in order to predict accurately their students' OPI ratings using the ACTFL Proficiency Guidelines; (d) in a proficiency‐oriented curriculum there is a relationship between classroom achievement and students' OPI ratings; and (e) teachers of proficiency‐oriented classes have some accurate intuitions regarding their students' oral progress and OPI ratings. This study provides valuable information for states and school districts as they assess student oral performance in an outcome‐based or standards‐driven curriculum.
Conceptualizing Willingness to Communicate in a L2: A Situational Model of L2 Confidence and Affiliation
Authors: MACINTYRE PETER D. , CLÉMENT RICHARD , DÖRNYEI ZOLTÁN , NOELS KIMBERLY A.
Published: October 2011

Why do some students seek, while others avoid, second language (L2) communication? Many language teachers have encountered students high in linguistic competence who are unwilling to use their L2 for communication whereas other students, with only minimal linguistic knowledge, seem to communicate in the L2 whenever possible. Despite excellent communicative competence, spontaneous and sustained use of the L2 is not ensured. A colleague, who teaches a L2 and whose L2 competence is excellent, is well known to avoid “like the plague” L2 communication in social settings. A related observation is that many learners have noticed that their willingness to communicate (WTC) varies considerably over time and across situations. Our aim in this article is twofold. First we wish to provide an account of the linguistic, communicative, and social psychological variables that might affect one's “willingness to communicate.” As demonstrated in the text below, and examination of WTC offers the opportunity to integrate psychological, linguistic, and communicative approaches to L2 research that typically have been independent of each other. We view the WTC model as having the potential to provide a useful interface between these disparate lines of inquiry. Our second goal is to suggest potential relations among these variables by outlining a comprehensive conceptual model that may be useful in describing, explaining, and predicting L2 communication. In an effort to move beyond linguistic or communicative competence as the primary goal of language instruction, this article represents an overt attempt to combine these disparate approaches in a common theme, that is, proposing WTC as the primary goal of language instruction.
Use of ionic dialysance to calculate Kt/V in pediatric hemodialysis
Authors: Marsenic Olivera , Booker Kristi , Studnicka Kathleen , Wilson Donna , Beck Ann , Swanson Tiffany , Henry Dwayne , Turman Martin
Published: October 2011

Online clearance (OLC) monitor measures conductivity difference between dialysate entering and leaving the dialyser. Derived ionic dialysance (ID) represents effective urea clearance from which Kt/V is calculated, allowing Kt/V monitoring at every treatment without blood sampling. We tested ID accuracy in children and provide recommendations for its use. Using Fresenius machines 2008 K with built‐in OLC monitors, we studied 45 hemodialysis (HD) sessions and 168 calculated Kt/V results in 11 patients. Urea distribution volume (V), needed to calculate Kt/V from ID, was estimated using three methods: Mellits and Cheek (MC), KDOQI recommended total body water nomograms (TBWN) and OLC‐derived independent from tested HD sessions. Reference spKt/V from pre‐ and post‐HD BUN (Daugirdas) was compared with Kt/V calculated from ID using three different estimated V's. ID was accurate in calculating Kt/V in children when V derived from OLC was used (P = 0.42), with absolute error 0.14 ± 0.12. If TBWN‐derived V was used, Kt/V was consistently underestimated by 0.32 ± 0.22. TBWN‐derived V can still be recommended for use with OLC for monitoring trend in Kt/V, if underestimation of spKt/V of average 0.3 is accounted for. MC‐derived V results in even greater underestimation of spKt/V and therefore cannot be recommended for use with OLC.
Medulloblastoma presenting as dialysis disequilibrium syndrome
Authors: Dilena Robertino , Paglialonga Fabio , Barbieri Sergio , Edefonti Alberto
Published: October 2011

Dialysis disequilibrium syndrome (DDS) is a central nervous system disorder that occurs during or after hemodialysis. This is caused by brain edema that manifests as neurological symptoms that include headache, emesis, nausea, blurring of vision, disturbed consciousness, tremors and seizures, and in severe cases, death. The incidence of DDS is very high among patients with preexisting neurological diseases. There has been much debate about the origin of DDS. We report a case of DDS, as presenting syndrome of a medulloblastoma in a child aged 5 years, and discuss the pathogenesis and the possible role of DDS for an earlier detection of occult brain lesions in dialyzed patients.
Metformin intoxication requiring dialysis
Authors: Nguyen Hoang‐Lan , Concepcion Luis
Published: October 2011

Metformin (MTF) is one of the most common oral agents used to treat diabetes mellitus. Intoxication is associated with lactic acidosis and has significant clinical consequences. We report 12 cases requiring dialytic intervention. Twelve patients were analyzed from 2005 to 2010; 10 of these patients were treated with dialysis. Conventional hemodialysis (HD) and continuous veno‐venous hemodialysis treatments with bicarbonate dialysis were used, and the results were presented as mean and standard deviation. The results are as follows: 33% of the patients were male, hospital stay was 9.3 (±12) days, average MTF dose 1.7 g/day, mortality was 25%. Baseline glomerular filtration rate for these patients was 51.5 mL/min, with an average age of 64 (±11) years. On presentation, all had acute kidney injury with blood urea nitrogen/creatinine 75 (±30)/8.1 (±3.7) mg/dL, lactic acid 12.4 (±8.1) mmol/L, pH 7.04 (±0.19), bicarbonate 7.2 (±4.5) mmol/L. Metformin level was 25 (±17) µg/mL; anion gap was 28 (±9), and serum potassium was 5.4 (±1.3) mEq/L. Seventy percent of patients were treated with conventional HD. Patients required 4 (±5) dialysis treatments at blood flow QB 330 (±53), dialysis flow QD 571 (±111) for 305 (±122) minutes. Postdialysis, the acidosis parameters improved: bicarbonate 19.2 (±4.1) mmol/L, lactic acid 6 (±4) mmol/L and MTF levels decreased 8.9 (±5.7) µg/mL. Metformin percentage removal was calculated to be 60% (±24). No difference was found between HD and continous veno‐venous hemodialysis. The only difference between survivors was the age 53 (±7) vs. 78 (±10) (P < 0.05). Metformin toxicity is a serious clinical condition and causes severe lactic acidosis and significant mortality. Hemodialysis is an efficient method to treat MTF intoxication and correct the metabolic abnormalities.
Predictive value of ridge dimensions on autologous bone graft resorption in staged maxillary sinus augmentation surgery using Cone‐Beam CT
Authors: Klijn R. J. , van den Beucken J. J. J. P. , Bronkhorst E. M. , Berge S. J. , Meijer G. J. , Jansen J. A.
Published: October 2011

Introduction:

No studies are available that provide predictive parameters regarding the expected amount of resorption after maxillary sinus augmentation surgery using autologous bone grafts. Therefore, the aim of this study was to determine parameters influencing the outcome of the bone graft resorption process.

Material and methods:

In 20 patients, three‐dimensional analysis of alveolar ridge dimensions and bone graft volume change in the atrophic posterior maxilla was performed by Cone‐Beam Computerized Tomography imaging. Ridge dimensions were assessed before maxillary sinus augmentation surgery. Bone graft volumes were compared after maxillary sinus floor augmentation surgery and a graft healing interval of several months. To analyze the relation between bone volume changes with the independent variables, patients’ gender, age, alveolar crest height and width, and graft healing time interval, a multi‐level extension of linear regression was applied.

Results:

A residual bone height of 6.0 mm (SD = 3.6 mm) and 6.2 mm (SD = 3.6 mm) was found at the left and right sides, respectively. Moreover, alveolar bone widths of 6.5 mm (SD = 2.2 mm) and 7.0 mm (SD = 2.3 mm) at the premolars, and 8.8 mm (SD = 2.2 mm) and 8.9 mm (SD = 2.5 mm) at the molars regions were found at the left and right site, respectively. Bone graft volume decreased by 25.0% (SD = 21.0%) after 4.7 months (SD = 2.7, median = 4.0 months) of healing time. The variables “age” (P = 0.009) and mean alveolar crest “bone height” (P = 0.043), showed a significant influence on bone graft resorption. A decrease of 1.0% (SE = 0.3%) of bone graft resorption was found for each year the patient grew older, and an increase in bone graft resorption of 1.8% (SE = 0.8%) was found for each mm of original bone height before sinus floor augmentation.

Conclusions:

Graft resorption occurs when using autologous bone grafts for maxillary sinus augmentation. Alveolar crest bone height and patient age have a significant effect on graft resorption, with increased resorption for higher alveolar crest bone height and decreased resorption for older patients. Consequently, patient characteristics that affect the process of bone graft resorption should be given full consideration, when performing sinus augmentation surgery.
The proteome and gene expression profile of cementoblastic cells treated by bone morphogenetic protein‐7 in vitro
Authors: Bozic Darko , Grgurevic Lovorka , Erjavec Igor , Brkljacic Jelena , Orlic Iva , Razdorov Genadij , Grgurevic Ivica , Vukicevic Slobodan , Plancak Darije
Published: October 2011

Aim

Regenerative periodontal therapy is often unpredictable and limited. Cementum regeneration is necessary for the proper repair of a periodontal ligament. The precise mechanism how bone morphogenetic protein‐7 (BMP7) induces differentiation and mineralization of cementoblasts remains undetermined. The purpose of this study was to evaluate the effect of BMP7 on early proteome and gene expression profile of cementoblastic OCCM.30 cells in vitro.

Materials and Methods

Immortalized murine cementoblasts (OCCM.30) were exposed to BMP7 and evaluated for: (1) proliferation; (2) mineralization; (3) early proteome profile using liquid chromatography‐mass spectrometry (LC‐MS); and (4) gene expression by quantitative RT‐PCR.

Results

Bone morphogenetic protein‐7 increased the cell proliferation at 24 h and 48 h, while higher doses suppressed the cell proliferation at 48 h. BMP7 induced the mineralization of cementoblasts following 8 days of therapy. Using LC‐MS we identified 1117 proteins from the cell lysate. Many belonged to extracellular matrix formation such as PCPE1, collagens, annexins and integrin receptors. RT‐PCR analyses revealed a BMP7 dose‐dependent upregulation of BMP1, TGFβ1, osterix, osteoprotegerin, procollagen I and II, PCPE1, and noggin, while BMP6 and chordin expression were decreased. The high BMP7 dose down regulated most of the genes 24 h following therapy.

Conclusion

Bone morphogenetic protein‐7 promotes differentiation and mineralization of cementoblasts via inducing PCPE1 and BMP1 responsible for processing of type I collagen.
Microparticles of Pregnant Women and Preeclamptic Patients Activate Endothelial Cells in the Presence of Monocytes
Authors: Lok Christine A. R. , Snijder Karin S. , Nieuwland Rienk , Van Der Post Joris A. M. , de Vos Paul , Faas Marijke M.
Published: October 2011

Citation Lok CAR, Snijder KS, Nieuwland R, Van Der Post JAM, de Vos P, Faas MM. Microparticles of pregnant women and preeclamptic patients activate endothelial cells in the presence of monocytes. Am J Reprod Immunol 2012; 67: 206–215

Problem  Preeclampsia is a pregnancy‐specific disorder that may result from an adverse maternal response to circulating placenta‐derived factors, causing a systemic inflammation including endothelial activation. Plasma from preeclamptic patients was shown to induce endothelial activation in the presence of monocytes. We investigated whether microparticles (MP) are the plasma factors causing this activation of endothelial cells.

Method of study  Monocultures and co‐cultures of monocytes and endothelial cells were incubated with plasma, MP‐poor plasma or isolated MP from non‐pregnant and pregnant women and preeclamptic patients (each n = 8). ICAM‐1 expression was analyzed with flow cytometry.

Results  The expression of ICAM‐1 was significantly increased in monocytes and endothelial cells in co‐cultures after the addition of isolated MP from preeclamptic patients (P = 0.017) and to a lesser extent in pregnant women (P = 0.012) compared to non‐pregnant controls.

Conclusions  Microparticles from preeclamptic patients activate endothelial cells in the presence of monocytes. Whether all MP have the same effect on monocytes and endothelial cells or only a specific subgroup is the focus of future research.
Association of IL‐1β and IL‐6 gene polymorphisms with recurrent spontaneous abortion in a Chinese Han population
Authors: Ma X. , Xu L.‐J. , Wang J. , Xian M.‐M. , Liu M.
Published: October 2011

As certain cytokines may play a role in unexplained recurrent spontaneous abortion (RSA) and also some cytokine gene polymorphisms may affect the level of cytokine production, the aim of this study was to investigate the relationship between Chinese RSA and polymorphisms of the genes coding for interleukin (IL)‐1β (−31C/T, −511C/T, +3954C/T) and IL‐6 (−634C/G). Women (n = 162) with at least three consecutive spontaneous abortions and 156 ethnically matched healthy women with at least one successful pregnancy were included. Genotypes were determined using restriction fragment length polymorphism analysis of polymerase chain reaction products. No significant differences were found in the IL‐1β−31T, −511T and +3954T distributions between the RSA group and the control group. On the other hand, the frequencies of the IL‐6−634GG genotype and −634G allele were significantly decreased in the RSA group versus the control group (genotype: P = 0.0003; allele: P = 0.002), suggesting the IL‐6−634C/G polymorphism might be a possible genetic protective factor for RSA.
Frequency dependence of the large frequency separation of solar-like oscillators: influence of the helium second-ionization zone
Authors: Hekker S. , Basu Sarbani , Elsworth Y. , Chaplin W. J.
Published: October 2011

The large frequency separation (Δν) between modes of the same degree and consecutive orders in a star is approximately proportional to the square root of its mean density. To determine Δν as accurately as possible, a mean large frequency separation (〈Δν〉) computed over several orders is often used. It is, however, known that Δν varies with frequency in a second-order effect. From observations, it has been shown that this frequency dependence is more important for main-sequence stars than it is for red giant stars. Here we use yrec models to verify and explain this observational result. We find that for stars with R ≳ 8 R⊙, the effect of the helium second-ionization zone (He ii zone) is relatively small. For these stars, the deep location of the He ii zone induces a frequency modulation covering only a few Δν, while the amplitude of the modulation is low due to the relatively weak and extended He ii layer, causing a shallow wide depression in the first adiabatic exponent (Γ1). For less evolved stars, the He ii zone is located closer to the surface, and it is more confined, i.e. a deep narrow depression in Γ1. This causes frequency modulations with relatively high amplitudes covering up to about 20Δν, inducing a relatively large frequency modulation. Additionally, we find that for less evolved stars, the He ii zone is stronger and more localized for more massive stars and for stars with low metallicities further increasing the amplitude of the frequency modulation.
Polyethylene Glycol Grafted Polyethylene: A Versatile Platform for Nonmigratory Active Packaging Applications
Authors: Barish Jeffrey A. , Goddard Julie M.
Published: October 2011

Abstract:  Nonmigratory active packaging, in which bioactive components are tethered to the package, offers the potential to reduce the need for additives in food products while maintaining safety and quality. A challenge in developing nonmigratory active packaging materials is the loss of biomolecular activity that can occur when biomolecules are immobilized. In this work, we describe a method in which a biocompatible polymer (polyethylene glycol, PEG) is grafted from the surface of ozone‐treated low‐density polyethylene (LDPE) resulting in a surface functionalized polyethylene to which a range of amine‐terminated bioactive molecules can be immobilized. Free radical graft polymerization is used to graft PEG onto the LDPE surface, followed by immobilization of ethylenediamine onto the PEG tether. Ethylenediamine was used to demonstrate that amine‐terminated molecules could be covalently attached to the PEG‐grafted film. Changes in surface chemistry and topography were measured by attenuated total reflectance Fourier transform infrared spectroscopy, contact angle, atomic force microscopy, scanning electron microscopy, and X‐ray photoelectron spectroscopy. We demonstrate the ability to graft PEG onto the surface of polymer packaging films by free radical graft polymerization, and to covalently link an amine‐terminated molecule to the PEG tether, demonstrating that amine‐terminated bioactive compounds (such as peptides, enzymes, and some antimicrobials) can be immobilized onto PEG‐grafted LDPE in the development of nonmigratory active packaging.

Practical Application:  Nonmigratory active packaging offers the potential for improving food safety and quality while minimizing the migration of the active agent into food. In this paper, we describe a technique to modify polyethylene packaging films such that active agents can be covalently immobilized by a biocompatible tether. Such a technique can be adapted to a number of applications such as antimicrobial, antioxidant, or immobilized enzyme active packaging.
Effect of Co‐Inoculation of Saccharomyces cerevisiae and Lactobacillus fermentum on the Quality of the Distilled Sugar Cane Beverage Cachaça
Authors: Duarte Whasley Ferreira , de Sousa Márcio Vinicius Ferreira , Dias Disney Ribeiro , Schwan Rosane Freitas
Published: October 2011

Abstract:  The effect of Lactobacillus fermentum in co‐inoculation with Saccharomyces cerevisiae UFLA CA11 on the quality of cachaça (sugar cane spirit) was evaluated. The co‐inoculation was first evaluated in flask fermentation, and subsequently, yeast and bacteria were co‐cultured at approximately 105 CFU/mL and 108 CFU/mL, respectively, in 4 consecutive batches. L. fermentum did not affect the growth or activity (sugar consumption and fermentation rate) of S. cerevisiae UFLA CA11 during fermentation. The physicochemical analysis revealed a higher concentration (Tukey test) of aldehydes (22.07 mg/100 mL anhydrous alcohol) in cachaça produced by co‐inoculation. Analysis of volatile compounds using GC‐FID demonstrated that cachaça produced by co‐inoculation had higher concentrations of acetaldehyde (25.15 mg/L), ethyl acetate (30.17 mg/L), and 2,3‐butanedione (170.39 μ/L), while cachaça produced by UFLA CA11 contained higher concentrations of ethyl lactate (1205.98 μ/L), propionic acid (127.97 μ/L), butyric acid (2335.57 μ/L), and 1‐pentanol (469.23 μ/L). The lowest concentration of acetic acid measured by HPLC was found in cachaça obtained with UFLA CA11. The sensory analysis, performed using the Mann–Whitney test, revealed that cachaça produced by co‐inoculation differed from that produced by UFLA CA11 in taste and aroma.

Practical Application:  This study reports on the use of a mixed culture of Saccharomyces cerevisae and Lactobacillus fermentum to produce cachaça and shows the influence of co‐inoculation of yeast and bacteria on the quality of this beverage.
Human neutrophil antigen and antibody studies: a Taiwanese experience
Authors: Chu C.‐C. , Lin M.
Published: October 2011

Neutrophil alloantibodies are clinically known to cause neonatal neutropenia and transfusion‐related lung injuries. Furthermore, neutrophil autoantibodies are associated with autoimmune neutropenia. This article is a review on neutrophil alloantigen in the Taiwanese population, and case investigations related to allo/auto neutrophil antibodies over a period of 20 years in the immunohaematology reference laboratory of Mackay Memorial Hospital, Taiwan.

In Taiwanese populations, HNA‐1a is more frequent than HNA‐1b (90% and 50% respectively) and HNA‐1c is not seen. Furthermore, the FcgRIIIb‐deficient individual homozygous for FCGR3B gene deletion is estimated to be approximately 1 in 180 and is not as rare as previously thought.

Although mothers homozygous for either HNA‐1a or HNA‐1b are commonly found in Taiwan, the number of patients with neonatal neutropenia caused by HNA‐1 alloantibodies is seldom seen. In a search among our previous laboratory requests of neonatal cases for granulocyte antibodies testing over a 10‐year period, only four cases showed neutrophil alloantibodies in the mother and baby’s sera.

Lastly, primary autoimmune neutropenia among 51 children was retrospectively investigated. The study revealed that the specificity of the autoantibody was most commonly directed against HNA‐1a. In addition, 31 cases were genotyped for HLA‐DRB1 and ‐DQB1 genes. The HLA allele HLA‐DQB1*05:03 was found to be associated with primary autoimmune neutropenia in Taiwan.
The role of the transfusion nurse in the hospital and blood centre
Authors: Bielby L. , Stevenson L. , Wood E.
Published: October 2011

The transfusion process is complex, involving many interlinking chains of events, and a multidisciplinary group of health professionals with different levels of awareness and understanding of transfusion practice. In recent years, many measures have been implemented to increase blood component safety and the clinical transfusion process. Haemovigilance programs report the greatest risks to patients from transfusion in many countries now relate to hospital‐based steps in the process.

The role of the Transfusion Nurse (TN) is evolving as an integral part of efforts to optimise appropriate use of blood components, reduce procedural risks and improve transfusion practice generally. The TN position is a relatively recent specialist role within hospitals and blood services, and continues to develop with growing experience of areas requiring intervention in the clinical setting, and increasing expectations for improvements in transfusion clinical governance.

The role typically includes activities to improve clinician and patient awareness of transfusion issues and practical knowledge of blood product use, and therefore to improve clinical decision‐making and enhance blood administration processes, along with responsibilities for education/training, auditing and adverse event follow‐up. Within the Blood Service in Australia the role also covers approval and provision of specialised blood products along with many of the hospital‐based TN functions.

The TN serves as an expert resource and has been fundamental in development of tools, resources and skills in the following areas:

‐ Patient blood management:

‐ Education

‐ Governance

‐ Professional development

‐ Research

Benchmarking across organizations has demonstrated that availability and review of comparative data can be a powerful motivator of change. Reviews of the TN role/programmes highlighted their effectiveness and resulted in ongoing support/funding. Skills and attributes such as confidence, persistence, energy, excellent communication/ technical knowledge and clinical experience are key requirements for the roles success.

Conclusion  The specialist transfusion practitioner/Transfusion Nurse is an integral part of a multidisciplinary team, supporting efforts at institutional and national levels to reduce transfusion risks and improve practice.
Fatigue Modeling of a Notched Flat Plate Under Variable Amplitude Loading Supported by Elastoplastic Finite Element Method Analyses
Authors: Pereira Hélder F. S. G. , De Jesus Abílio M. P. , Ribeiro Alfredo S. , Fernandes António A.
Published: October 2011

Although intensive research has been carried out to understand the fatigue behavior of steel notched components, under variable amplitude loading, no definite and general robust models have been derived so far. Therefore, every effort to augment the knowledge in this topic is welcomed. Within this context, existing variable amplitude data, derived by the authors for a notched low carbon pressure vessel steel (P355NL1) flat plate, is used to assess a local approach to fatigue. A linear damage summation framework, supported by elastoplastic finite element analyses, is used. Several variable amplitude loadings were selected and analyzed, using alternative configurations of kinematic hardening plasticity models (e.g., Chaboche’s model with distinct constants superposition). The predictions are assessed using available experimental data and data derived with simplified empirical elastoplastic tools. This paper highlights the difficulties of performing such elastoplastic analysis and compares the obtained results with those obtained using more classical tools for elastoplastic analysis (Glinka and Seeger–Heuler). It was found that fatigue predictions based on an elastoplastic finite element analysis, made using the Chaboche’s model, were significantly more accurate than predictions based on simplified elastoplastic analysis. These results have important practical relevance.
Modeling Interparticle Size Effect on Deformation Behavior of Metal Matrix Composites by a Gradient Enhanced Plasticity Model
Authors: Abu Al-Rub Rashid K. , Ettehad Mahmood
Published: October 2011

Experimental tests show that particle (inclusion or precipitate) size and interparticle spacing, besides volume fraction, have a considerable effect on the macroscopic mechanical response of metal matrix microreinforced composites. Classical (local) plasticity models unlike nonlocal gradient enhanced plasticity models cannot capture this size dependency due to the absence of a material length scale. In this paper, one form of higher-order gradient plasticity enhanced model, which is derived based on principle of virtual power and laws of thermodynamic, is employed to investigate the size effect of elliptical inclusions with different aspect ratios based on unit cell simulations. It is shown that by decreasing the particle size or equivalently the interparticle spacing (i.e., the spacing between the centers of inclusions), while keeping the volume fraction constant, the average stress–strain response is stronger and more sensitive to the inclusion’s aspect ratio. However, unexpectedly, decreasing the free-path interparticle spacing (i.e., the spacing between the edges of inclusions perpendicular to the principal loading direction) does not necessarily lead to largest strengthening. This is completely dependent on the plastic strain gradient hardening due to distribution and evolution of geometrically necessary dislocations that depend on the particle size and shape. Gradient-hardening significantly alter the stress and plastic strain distributions near the particle-matrix interface.
Reference dosimetry for helical tomotherapy: Practical implementation and a multicenter validation
Authors: De Ost B. , Schaeken B. , Vynckier S. , Sterpin E. , Van den Weyngaert D.
Published: October 2011

Purpose:

The aim of this study was to implement a protocol for reference dosimetry in tomotherapy and to validate the beam output measurements with an independent dosimetry system.

Methods:

Beam output was measured at the reference depth of 10 cm in water for the following three cases: (1) a 5 × 10 cm2 static machine specific reference field (MSR), (2) a rotational 5 × 10 cm2 field without modulation and no tabletop in the beam, (3) a plan class specific reference (PCSR) field defined as a rotational homogeneous dose delivery to a cylindrical shaped target volume: plan with modulation and table‐top movement. The formalism for reference dosimetry of small and nonstandard fields [Med.Phys.35: 5179–5186, 2008] and QA recommendations [Med.Phys.37: 4817–4853, 2010] were adopted in the dose measurement protocol. All ionization chamber measurements were verified independently using alanine/EPR dosimetry. As a pilot study, the beam output was measured on tomotherapy Hi‐art systems at three other centers and directly compared to the centers specifications and to alanine dosimetry.

Results

: For the four centers, the mean static output at a depth of 10 cm in water and SAD = 85 cm, measured with an A1SL chamber following the TG‐148 report was 6.238 Gy/min ± 0.058 (1 SD); the rotational output was 6.255 Gy/min ± 0.069 (1 SD). The dose stated by the center was found in good agreement with the measurements of the visiting team:Dcenter/Dvisit = 1.000 ± 0.003 (1 SD). The A1SL chamber measurements were all in good agreement with Alanine/EPR dosimetry. Going from the static reference field to the rotational/non modulated field the dose rate remains constant within 0.2% except for one center where a deviation of 1.3% was detected.

Conclusions:

Following the TG‐148 report, beam output measurements in water at the reference depth using a local protocol, as developed at different centers, was verified. The measurements were found in good agreement with alanine/EPR dosimetry. The presented methodology may provide a good concept for reference dosimetry.
A comparison of postimplant dosimetry for 103Pd versus 131Cs seeds on a retrospective series of PBSI patients
Authors: Ravi Ananth , Keller Brian M. , Pignol Jean‐Philippe
Published: October 2011

Purpose:

Permanent breast seed implantation (PBSI) is an accelerated partial breast irradiation technique performed using stranded103Pd radioactive seeds (average energy of 21 keV, 16.97 day half‐life). Since 2004, 131Cs brachytherapy sources have become clinically available. The 131Cs radionuclide has a higher energy (average energy of 30 keV) and a shorter half‐life (9.7 days) than 103Pd. The purpose of this study was to determine whether or not there are dosimetric benefits to using 131Cs brachytherapy seeds for PBSI.

Methods:

The prescribed dose for PBSI using103Pd is 90 Gy, which was adjusted for 131Cs implants to account for the shorter half‐life. A retrospective cohort of 30 patients, who have already undergone a 103Pd implant, was used for this study. The treatments were planned using the Variseed treatment planning system. The air kerma strength of the 131Cs seeds was adjusted in all preimplantation treatment plans so that the V100 (the volume within the target that receives 100% or more of the prescribed dose) were equivalent at time of implantation. Two month follow‐up CT scans were available for all 30 patients and each patient was reevaluated using 131Cs seeds. The postimplant dosimetric parameters were compared using a two tailed t‐test.

Results:

The prescribed dose for131Cs was calculated to be 77 Gy; this dose would have the same biological effect as a PBSI implant with 103Pd of 90 Gy. The activities of the 131Cs sources were adjusted to an average of 2.2 ± 0.8 U for 131Cs compared to 2.5 ± 1.1 U for 103Pd in order to get an equivalent V100 as the 103Pd preimplants. While the use of 131Cs significantly reduces the preimplant V200 (the volume within the target that receives 200% or more of the prescribed dose) compared to 103Pd by 13.5 ± 9.0%, the reduction observed on the 2 month postimplant plan was 12.4 ± 5.1% which accounted for seed motion, implantation inaccuracies and tissue changes. This translates into an absolute reduction of 4.1 cm3 of tissue receiving 200% of the dose.

Conclusions:

This analysis of 30 early stage breast cancer patients who underwent the PBSI procedure shows that there is a theoretical dosimetric advantage to using131Cs. However, in a realistic implant that will have seed misplacements and tissue changes, the use of 131Cs may not result in any clinically significant benefit.
Task‐based weights for photon counting spectral x‐ray imaging
Authors: Bornefalk Hans
Published: October 2011

Purpose:

To develop a framework for taking the spatial frequency composition of an imaging task into account when determining optimal bin weight factors for photon counting energy sensitive x‐ray systems. A second purpose of the investigation is to evaluate the possible improvement compared to using pixel based weights.

Methods:

The Fourier based approach of imaging performance and detectability indexd′ is applied to pulse height discriminating photon counting systems. The dependency of d′ on the bin weight factors is made explicit, taking into account both differences in signal and noise transfer characteristics across bins and the spatial frequency dependency of interbin correlations from reabsorbed scatter. Using a simplified model of a specific silicon detector, d′ values for a high and a low frequency imaging task are determined for optimal weights and compared to pixel based weights.

Results:

The method successfully identifies bins where a large point spread function degrades detection of high spatial frequency targets. The method is also successful in determining how to downweigh highly correlated bins. Quantitative predictions for the simplified silicon detector model indicate that improvements in the detectability index when applying task‐based weights instead of pixel based weights are small for high frequency targets, but could be in excess of 10% for low frequency tasks where scatter‐induced correlation otherwise degrade detectability.

Conclusions:

The proposed method makes the spatial frequency dependency of complex correlation structures between bins and their effect on the system detective quantum efficiency easier to analyze and allows optimizing bin weights for given imaging tasks. A potential increase in detectability of double digit percents in silicon detector systems operated at typical CT energies (100 kVp) merits further evaluation on a real system. The method is noted to be of higher relevance for silicon detectors than for cadmium (zink) telluride detectors.
Pre-Clovis Mastodon Hunting 13,800 Years Ago at the Manis Site, Washington
Authors: Waters Michael R. , Stafford Thomas W. , McDonald H. Gregory , Gustafson Carl , Rasmussen Morten , Cappellini Enrico , Olsen Jesper V. , Szklarczyk Damian , Jensen Lars Juhl , Gilbert M. Thomas P. , Willerslev Eske
Published: October 2011

Further dating of the Manis site shows that people were hunting mastodons in North America by 14,000 years ago.
Detection of the Water Reservoir in a Forming Planetary System
Authors: Hogerheijde Michiel R. , Bergin Edwin A. , Brinch Christian , Cleeves L. Ilsedore , Fogel Jeffrey K. J. , Blake Geoffrey A. , Dominik Carsten , Lis Dariusz C. , Melnick Gary , Neufeld David , Panić Olja , Pearson John C. , Kristensen Lars , Yıldız Umut A. , van Dishoeck Ewine F.
Published: October 2011

The detection of cold water vapor in a nearby planet-forming disk suggests that water ice exists in its outer regions.
Antimicrobial Peptides Keep Insect Endosymbionts Under Control
Authors: Login Frédéric H. , Balmand Séverine , Vallier Agnès , Vincent-Monégat Carole , Vigneron Aurélien , Weiss-Gayet Michèle , Rochat Didier , Heddi Abdelaziz
Published: October 2011

A beetle species synthesizes an antimicrobial peptide to constrain a bacterial symbiont in specialized organs.
Sybil, Inc.
Sybil Exposed
The Extraordinary Story Behind the Famous Multiple Personality Case

by Debbie Nathan

Free Press (Simon and Schuster), New York, 2011. 328 pp. $26, C$29.99, £16.95. ISBN 9781439168271.
Authors: Harris Ben
Published: October 2011

Nathan's cautionary tale documents a patient, a clinician, and a journalist colluding to create an imaginary psychiatric disorder.
Vaccine Trial Meets Modest Expectations, Buoys Hopes
Authors: Vogel Gretchen , Roberts Leslie
Published: October 2011

Initial results from the world's first large-scale trial of a malaria vaccine show that it reduced episodes of the disease by about half in babies and toddlers.
Navy Dives Into Program Offering Cash for Good Scores
Authors: Mervis Jeffrey
Published: October 2011

A $1.1 million federal grant to a Texas-based nonprofit organization trying to improve U.S. math and science education could prompt a closer look at the controversial practice of paying students to do well on standardized tests.
China Looks to Purge Academia of 'Trash Journals'
Authors: Hvistendahl Mara
Published: October 2011

The Chinese government is getting serious about raising standards in the country's academic publishing industry and weeding out slapdash and irrelevant publications read by next to no one.
Social Science for Pennies
Authors: Bohannon John
Published: October 2011

Social scientists are turning to online retail giant Amazon.com to cheaply recruit people around the world for research studies
Evaluation of Six Commercial Point-of-Care Tests for Diagnosis of Acute Dengue Infections: the Need for Combining NS1 Antigen and IgM/IgG Antibody Detection To Achieve Acceptable Levels of Accuracy
Authors: Blacksell Stuart D. , Jarman Richard G. , Bailey Mark S. , Tanganuchitcharnchai Ampai , Jenjaroen Kemajittra , Gibbons Robert V. , Paris Daniel H. , Premaratna Ranjan , de Silva H. Janaka , Lalloo David G. , Day Nicholas P. J.
Published: October 2011

Six assays were evaluated in this study to determine their suitability for the diagnosis of acute dengue infection using samples from 259 Sri Lankan patients with acute fevers (99 confirmed dengue cases and 160 patients with other confirmed acute febrile illnesses): (i) the Merlin dengue fever IgG & IgM combo device (Merlin), (ii) the Standard Diagnostics Dengue Duo nonstructural 1 (NS1) antigen and IgG/IgM combo device (Standard Diagnostics, South Korea), (iii) the Biosynex Immunoquick dengue fever IgG and IgM (Biosynex, France) assay, (iv) the Bio-Rad NS1 antigen strip (Bio-Rad, France), (v) the Panbio Dengue Duo IgG/IgM Cassette (Inverness, Australia), and (vi) the Panbio dengue NS1 antigen strip (Inverness, Australia). The median number of days of fever prior to admission sample collection was 5 days (interquartile range, 3 to 7 days). Sensitivity and specificity of the NS1 antigen tests ranged from 49 to 59% and from 93 to 99%, respectively, and sensitivity and sensitivity of the IgM antibody test ranged from 71 to 80% and from 46 to 90%, respectively. Combining the NS1 antigen and IgM antibody results from the Standard Diagnostics Dengue Duo test gave the best compromise of sensitivity and specificity (93% and 89%, respectively) and provided the best sensitivity in patients presenting at different times after fever onset. The Merlin IgM/IgG antibody tests correctly classified 64% and 86% of the primary and secondary dengue infection cases, respectively, and the Standard Diagnostics IgM/IgG antibody tests correctly classified 71% and 83% of the primary and secondary dengue infection cases, respectively. This study provides strong evidence of the value of combining dengue antigen- and antibody-based test results in the rapid diagnostic test (RDT) format for the acute diagnosis of dengue.
Disseminated Trichosporonosis in a Burn Patient: Meningitis and Cerebral Abscess Due to Trichosporon asahii
Authors: Heslop Orville D. , Nyi Nyi May-Phyo , Abbott Sean P. , Rainford Lois E. , Castle Daphney M. , Coard Kathleen C. M.
Published: October 2011

A 44-year-old diabetic female presented to a hospital in Jamaica with thermal burns.
Trichosporon asahii
was isolated from facial wounds, sputum, and a meningeal swab. Dissemination of the fungus was demonstrated in stained histological sections of the meninges and a brain abscess at autopsy. Pure growth of the fungus from patient samples submitted and an environmental isolate obtained from a wash basin in the hospital supported the diagnosis.
Sudden Death of a Young Adult Associated with Bacillus cereus Food Poisoning
Authors: Naranjo María , Denayer Sarah , Botteldoorn Nadine , Delbrassinne Laurence , Veys Jean , Waegenaere Jacques , Sirtaine Nicolas , Driesen Ronald B. , Sipido Karin R. , Mahillon Jacques , Dierick Katelijne
Published: October 2011

A lethal intoxication case, which occurred in Brussels, Belgium, is described. A 20-year-old man died following the ingestion of pasta contaminated with
Bacillus cereus
. Emetic strains of
B. cereus
were isolated, and high levels of cereulide (14.8 μg/g) were found in the spaghetti meal.
Clostridium botulinum Group I Strain Genotyping by 15-Locus Multilocus Variable-Number Tandem-Repeat Analysis
Authors: Fillo Silvia , Giordani Francesco , Anniballi Fabrizio , Gorgé Olivier , Ramisse Vincent , Vergnaud Gilles , Riehm Julia M. , Scholz Holger C. , Splettstoesser Wolf D. , Kieboom Jasper , Olsen Jaran-Strand , Fenicia Lucia , Lista Florigio
Published: October 2011

Clostridium botulinumis a taxonomic designation that encompasses a broad variety of spore-forming, Gram-positive bacteria producing the botulinum neurotoxin (BoNT).C. botulinumis the etiologic agent of botulism, a rare but severe neuroparalytic disease. Fine-resolution genetic characterization ofC. botulinumisolates of any BoNT type is relevant for both epidemiological studies and forensic microbiology. A 10-locus multiple-locus variable-number tandem-repeat analysis (MLVA) was previously applied to isolates ofC. botulinumtype A. The present study includes five additional loci designed to better address proteolytic B and F serotypes. We investigated 79C. botulinumgroup I strains isolated from human and food samples in several European countries, including types A (28), B (36), AB (4), and F (11) strains, and 5 nontoxicClostridium sporogenes. Additional data were deduced fromin silicoanalysis of 10 available fully sequenced genomes. This 15-locus MLVA (MLVA-15) scheme identified 86 distinct genotypes that clustered consistently with the results of amplified fragment length polymorphism (AFLP) and MLVA genotyping in previous reports. An MLVA-7 scheme, a subset of the MLVA-15, performed on a lab-on-a-chip device using a nonfluorescent subset of primers, is also proposed as a first-line assay. The phylogenetic grouping obtained with the MLVA-7 does not differ significantly from that generated by the MLVA-15. To our knowledge, this report is the first to analyze genetic variability among all of theC. botulinumgroup I serotypes by MLVA. Our data provide new insights into the genetic variability of group IC. botulinumisolates worldwide and demonstrate that this group is genetically highly diverse.
Emergence of a New Swine H3N2 and Pandemic (H1N1) 2009 Influenza A Virus Reassortant in Two Canadian Animal Populations, Mink and Swine
Authors: Tremblay Donald , Allard Véronique , Doyon Jean-François , Bellehumeur Christian , Spearman J. Grant , Harel Josée , Gagnon Carl A.
Published: October 2011

A swine H3N2 (swH3N2) and pandemic (H1N1) 2009 (pH1N1) influenza A virus reassortant (swH3N2/pH1N1) was detected in Canadian swine at the end of 2010. Simultaneously, a similar virus was also detected in Canadian mink based on partial viral genome sequencing. The origin of the new swH3N2/pH1N1 viral genes was related to the North American swH3N2 triple-reassortant cluster IV (for hemagglutinin [HA] and neuraminidase [NA] genes) and to pH1N1 for all the other genes (M, NP, NS, PB1, PB2, and PA). Data indicate that the swH3N2/pH1N1 virus can be found in several pigs that are housed at different locations.
Latent HIV-1 Infection of Resting CD4
+
T Cells in the Humanized Rag2
−/−
γ
c
−/−
Mouse
Authors: Choudhary Shailesh K. , Archin Nancie M. , Cheema Manzoor , Dahl Noelle P. , Garcia J. Victor , Margolis David M.
Published: October 2011

Persistent human immunodeficiency virus type 1 (HIV-1) infection of resting CD4
+
T cells, unaffected by antiretroviral therapy (ART), provides a long-lived reservoir of HIV infection. Therapies that target this viral reservoir are needed to eradicate HIV-1 infection. A small-animal model that recapitulates HIV-1 latency in resting CD4
+
T cells may accelerate drug discovery and allow the rational design of nonhuman primate (NHP) or human studies. We report that in humanized Rag2
−/−
γ
c
−/−
(hu-Rag2
−/−
γ
c
−/−
) mice, as in humans, resting CD4
+
T cell infection (RCI) can be quantitated in pooled samples of circulating cells and tissue reservoirs (e.g., lymph node, spleen, bone marrow) following HIV-1 infection with the CCR5-tropic JR-CSF strain and suppression of viremia by ART. Replication-competent virus was recovered from pooled resting CD4
+
T cells in 7 of 16 mice, with a median frequency of 8 (range, 2 to 12) infected cells per million T cells, demonstrating that HIV-1 infection can persist despite ART in the resting CD4
+
T cell reservoir of hu-Rag2
−/−
γ
c
−/−
mice. This model will allow rapid preliminary assessments of novel eradication approaches and combinatorial strategies that may be challenging to perform in the NHP model or in humans, as well as a rigorous analysis of the effect of these interventions in specific anatomical compartments.