bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular and Immunologic Aspects of the Nonclassical HLA Class I Antigen HLA‐G: Evidence for an Important Role in the Maternal Tolerance of the Fetal Allograft
Authors: MOREAU PHILIPPE , PAUL PASCALE , ROUAS‐FREISS NATHALIE , KIRSZENBAUM MAREK , DAUSSET JEAN , CAROSELLA EDGARDO D.
Published: September 2011

PROBLEM: Human leukocyte antigen (HLA)‐G is a major histocompatibility complex class I antigen, which is referred to as nonclassical because it displays a tissue‐restricted distribution in the placenta, a reduced cytoplasmic domain, a limited polymorphism, and several isoforms. The HLA‐G antigen is thought to play an essential role during pregnancy by protecting the semi‐allogeneic fetus from recognition and destruction by maternal immune cells.

METHOD OF STUDY: Alternative splicing of HLA‐G mRNA was analyzed by Southern blot of reverse transcriptase‐polymerase chain reaction products from trophoblasts of the first trimester of gestation and term placenta. The regulation of HLA‐G gene expression was investigated by electrophoretic mobility shift assays using nuclear extracts from cells expressing different levels of HLA‐G gene activity. Using polymerase chain reaction‐single strand conformational polymorphism and sequencing, we studied HLA‐G gene polymorphism in families from the Centre d'Etude du Polymorphisme Humain in Paris. To understand the function of the HLA‐G molecule, cytotoxicity assays were carried out with peripheral blood mononuclear cells or polyclonal natural killer effectors cells from 30 different donors against HLA‐G1 and HLA‐G2 transfectants.

RESULTS: Four main aspects have been elucidated: 1) The primary transcript of the HLA‐G gene is alternatively spliced into five main mRNA forms: HLA‐G1 (full length), HLA‐G2 (minus exon 3), which encodes a membrane‐bound isoform associated with beta‐2 microglobulin, HLA‐G3 (minus exons 3 and 4), HLA‐G4 (minus exon 4), and HLA‐G5 (plus intron 4), which encodes a soluble form of the HLA‐G antigen; 2) specific nuclear factors bind to an important regulatory element located more than 1.2 kb from the HLA‐G gene. Three specific complexes are observed in cells that show HLA‐G transcriptional activity and an additional factor that could correlate with the repression of HLA‐G gene expression that is detected in natural killer cells; 3) we observed an important genomic polymorphism in exon 3 but a very low polymorphism at the protein level; 4) HLA‐G1 and HLA‐G2 transfectants clearly demonstrated that both HLA‐G isoforms are capable of inhibiting natural killer lytic activity.

CONCLUSION: These results suggest that HLA‐G acts as the public ligand for natural killer inhibitory receptors, thus protecting the fetus against maternal rejection.
Regulation of Major Histocompatibility Complex and TAP Gene Products in Preimplantation Mouse Stage Embryos
Authors: COOPER J. C. , FERNANDEZ N. , JOLY E. , DEALTRY G. B.
Published: September 2011

PROBLEM: To determine the ontogeny of major histocompatibility complex (MHC) expression and TAP products in mouse embryos.

METHOD OF STUDY: mRNAs encoding MHC and associated molecules were identified by reverse transcriptase‐polymerase chain reaction, and the protein products were localized by confocal microscopy.

RESULTS: mRNAs encoding class Ia (H‐2Db) and class Ib (Q7/9) were present in one‐cell embryos, whereas β2‐microglobulin (β2‐m) transcripts were not detected until the two‐cell stage. Transporter TAP1, but not TAP2, transcripts were detected only in blastocysts. H‐2 class Ia (classical) protein was detected on the surface of two‐cell embryos, H‐2 class Ib (nonclassical) protein was detected on one‐cell embryos, and β2‐m transcripts were detected on eight‐cell embryos; TAP1 protein was present at low levels in the cytoplasm from the one‐cell stage onward, increasing in expression in blastocysts.

CONCLUSIONS: In mice, MHC class I mRNAs encoding the heavy chain of H‐2‐ and Q7/9‐encoding Qa2 molecules are synthesized soon after conception prior to implantation. Similarly, the nonpolymorphic MHC class I‐associated molecule β2‐m also is expressed before implantation. TAP1, but not TAP2, is first detected at the blastocyst stage, thus preceding the onset of TAP2 in embryonic development.
Analysis of Human Leukocyte Antigen‐G Polymorphism Including Intron 4 in Japanese Couples with Habitual Abortion
Authors: Yamashita Takahiro , Fujii Tomoyuki , Tokunaga Katsushi , Tadokoro Kenji , Hamai Yoko , Miki Akinori , Kozuma Shiro , Juji Takeo , Taketani Yuji
Published: September 2011

PROBLEM: The purpose of this study was to clarify whether there is a difference between the allele frequency of human leukocyte antigen (HLA)‐G in healthy Japanese people and that of Japanese couples with habitual abortion.

METHOD OF STUDY: Exons 2, 3, 4, and intron 4 of the HLA‐G gene were analyzed in 20 couples with habitual abortion, using polymerase chain reaction (PCR)‐single‐strand conformation polymorphism (SSCP) analysis. Intron 4 of the HLA‐G gene was also analyzed in 54 healthy individuals. The nucleotide sequence of the PCR product of intron 4 was further determined by direct sequencing.

RESULTS: Two kinds of nucleotide sequence were identified in intron 4 of the HLA‐G gene, one of which was identical to that of HLA‐G*01011, and the other was identical to that of HLA‐G*01012, G*01013, and G*0104. The frequency of each allele in affected women and their husbands did not significantly differ from that of healthy individuals, and no mutation was found in any affected couple.

CONCLUSION: HLA‐G allelic abnormality seemed to have little, if any, implication in the pathogenesis of habitual abortion.
The Effect of Nitric Oxide on Sperm Cell Function and Embryo Development
Authors: Joo Bo Sun , Park Sea Hee , Park Sue Jin , Kang Ho Sung , Moon Hwa Sook , Kim Han Do
Published: September 2011

Joo BS, Park SH, Park SJ, Kang HS, Moon HS, Kim HD. The effect of nitric oxide on sperm cell function and embryo development. AJRI 1999; 42:327–334 © Munksgaard, Copenhagen

PROBLEM; Nitric oxide (NO) has been known to have multifunctional roles both in the male and female reproductive systems. We investigated the effects of sodium nitroprusside (SNP)‐dependent NO release on sperm cell function and embryo development to elucidate the mechanisms of action of NO.

METHOD OF STUDY: Semen samples from 20 healthy men were processed by the swim‐up method. Sperm motility, hyperactivation, and acrosome reaction were examined following incubation with various concentrations of SNP. The concentration of 10 nM to 1 mM was used for sperm motility and hyperactivation measurement and 1 μM to 1 mM for examining the effect on acrosome reaction. Embryo development to blastocyst stage was assessed using 100 nM to 1 mM of SNP added before transferring the mouse embryos into the culture medium. Finally, to understand the mechanism of action of NO, changes in embryo development were examined after zygotes were treated with various concentrations ranging up to 1 mM of 8‐bromo‐cGMP, an analog of cGMP.

RESULTS: Both sperm motility and hyperactivation were significantly reduced at 100 μM and 1 mM concentrations of SNP after 6 hr of incubation. After 24 hr of incubation, they were greatly decreased with all, except the 10 nM concentration of SNP. The percentage of acrosomal‐reacted spermatozoa was increased with the increasing concentration of SNP following incubation with 10 μM and 1 mM of SNP. Embryo development was arrested since the two‐cell embryonic stage with all except the 100 nM concentration of SNP, and inhibited by 200 μM of SNP regardless of SNP treatment stage. However, embryo development was not influenced by 8‐bromo‐cGMP.

CONCLUSIONS: We concluded that SNP‐inhibited sperm cell function and embryo development in a dose‐ and time‐dependent manner, and the inhibitory effect on embryo development, may not be a stage‐specific treatment mediated via a cGMP‐independent pathway. This result suggests that NO may be enough to affect the fecundity potential in vivo.
Spontaneous and Induced Release of Prostaglandins, Interleukin (IL)‐1β, IL‐6, and Tumor Necrosis Factor‐α by Placental Tissue from Normal and Preeclamptic Pregnancies
Authors: Munno Irene , Chiechi Luigi M. , Lacedra Giuseppe , Putignano Giuseppe , Patimo Caterina , Lobascio Anna , Loizzi Pasquale
Published: September 2011

Munno I, Chiechi LM, Lacedra G, Putignano G, Patimo C, Lobascio A, Loizzi P. Spontaneous and induced release of prostaglandins, interleukin (IL)‐1β, IL‐6, and tumor necrosis factor‐α by placental tissue from normal and preeclamptic pregnancies. AJRI 1999; 42:369–374 © Munksgaard, Copenhagen

PROBLEM: The objective of this study was to clarify the role of the main proinflammatory cytokines (interleukin [IL]‐1, IL‐6, tumor necrosis factor [TNF]‐α) in the pathogenesis of preeclampsia and how these cytokines affect one another and the production of prostaglandins (PGs).

METHOD OF STUDY: The concentrations of cytokines and PGs in supernatants of placental tissue from preeclamptic and normal women were determined by enzyme‐linked immunosorbent assay.

RESULTS: The concentrations of the PGs from unstimulated preeclamptic placental tissue were significantly higher compared to the concentrations of PGs from normal unstimulated placental tissue. Significant levels of IL‐1β were observed only in the supernatants of preeclamptic placental tissue. Of interest, an increase in TNF‐α production was detected in the supernatants of IL‐1‐stimulated preeclamptic placental tissue.

CONCLUSIONS: The overproduction of TNF‐α may be related not only to the effect of a stimulant like IL‐1β, but mainly to the lack of mechanisms down‐regulating the production of TNF‐α.
Interleukin‐8 Stimulates Placental Prostacyclin Production in Preeclampsia
Authors: Wang Yuping , Baier John , Adair C. David , Lewis David F. , Krueger Stephan , Kruger Tom , Gurski Michael , Brown Edwin
Published: September 2011

Wang Y, Baier J, Adair CD, Lewis DF, Krueger S, Kruger T, Gurski M, Brown E. Interleukin‐8 stimulates placental prostacyclin production in preeclampsia. AJRI 1999; 42:375–380 © Munksgaard, Copenhagen

PROBLEM: Our purpose was to determine placental interleukin (IL)‐8 production and its correlation with the prostacyclin production in normal and preeclamptic pregnancies and to evaluate the beneficial effect of IL‐8 on prostacyclin production.

METHOD OF STUDY: We determined 1) the in vitro production of IL‐8 and prostacyclin by placental villous tissues from normal and preeclamptic pregnancies and 2) the production of prostacyclin by villous tissues from preeclampsia treated with recombinant human IL‐8 (rhIL‐8). IL‐8 levels were measured by enzyme‐linked immunosorbent assay and prostacyclin by radioimmunoassay of 6‐keto PGF1α, the stable metabolite of prostacyclin.

RESULTS: 1) Placental production of IL‐8 and 6‐keto PGF1α were significantly less in preeclampsia than in normal pregnancies, P < 0.05. 2) Placental production of 6‐keto PGF1α and IL‐8 was significantly correlated in preeclampsia, P < 0.01. 3) Placental tissues treated with IL‐8 exhibited a concentration‐dependent increase in 6‐keto PGF1α production.

CONCLUSIONS: Placental tissues from preeclampsia produce significantly less IL‐8 than tissues from normal pregnancies, which correlates with decreased prostacyclin production. IL‐8 improves placental prostacyclin production in preeclampsia.
Human Decidualized Endometrial T Lymphocytes Do Not Substantially Down‐Regulate CD3ζ
Authors: Bedenicki Ivica , Newton Darren J. , Flanagan Brian F. , Johnson Peter M. , Rukavina Daniel , Christmas Dr. Stephen E.
Published: September 2011

PROBLEM: The T‐cell antigen receptor (TCR) has been reported to be down‐regulated on T‐cells in the decidualized endometrium in early pregnancy.

METHOD OF STUDY: The expression of CD3ζ, a component of the TCR complex, has been investigated in human first‐trimester decidual T‐cells using flow cytometric analysis of permeabilized cells.

RESULTS: Levels of CD3ζ expression were significantly lower in decidual than in peripheral T‐cells from non‐pregnant women, as assessed by mean fluorescence intensity (4.2 vs. 5.5. logarithmic scale, P < 0.05). However, when decidual and peripheral T‐cells from the same subjects were analyzed (n = 10), mean levels of CD3ζ were slightly, but not significantly, lower in decidual than in peripheral T‐cells (P > 0.1). CD3ζ was not substantially down‐regulated systemically as mean cytoplasmic CD3ζ levels did not differ significantly between peripheral blood T‐cells from pregnant women and non‐pregnant controls (P > 0.2). CD8+ cells outnumber CD4+ cells in decidua, but neither the proportions of these two T‐cell subsets positive for cytoplasmic CD3ζ nor the mean levels of CD3ζ were significantly different.

CONCLUSIONS: These results indicate that human decidual T‐cells do not greatly down‐regulate CD3ζ, but it is unclear if a small decrease in mean levels may be sufficient to compromise their capacity for activation.
Up‐Regulation of Natural Killer Cell Cytotoxicity by Interleukin‐2: The Effect of Sex and Parity
Authors: Brett Rose , Searle Roger F. , Bulmer Dr. Judith N.
Published: September 2011

PROBLEM: Peripheral blood lymphocytes (PBLs) from some, but not all, female donors showed increased cytotoxicity in response to interleukin (IL)‐2.

METHOD OF STUDY: The effect of IL‐2 on natural killer (NK) cell cytotoxicity was compared in nulliparous females, parous females, and males. Peripheral blood lymphocytes were preincubated for 20 or 72 hr with 5 or 100 U/ml IL‐2 and cytotoxicity against K562 targets was then examined.

RESULTS: In the parous females, only the 72‐hr preincubation with 100 U/ml IL‐2 significantly increased NK cell cytotoxicity, whereas nulliparous females also showed significantly increased cytotoxicity after a 20‐hr preincubation with 100 U/ml IL‐2. Neither female subject group had increased activity after preincubation for 20 or 72 hr with 5 U/ml IL‐2. However, male peripheral blood lymphocytes also showed a significant increase in NK cell cytotoxicity when preincubated for 72 hr with 5 U/ml IL‐2.

CONCLUSIONS: The effect of IL‐2 on NK cell cytotoxic activity may be related to sex and the state of parity.
Transforming Growth Factor‐β Isoforms and Receptors in Endometriotic Cysts of the Human Ovary
Authors: Tamura Mitsutoshi , Fukaya Takao , Enomoto Akemi , Murakami Takashi , Uehara Shigeki , Yajima Akira
Published: September 2011

PROBLEM: The present study examined the presence and cellular distribution of transforming growth factor‐β1, 2, and 3 isoforms and their type I and II receptors in endometriotic cysts of the ovary, relative to their presence in normal endometrial tissue.

METHOD OF STUDY: Thirteen control samples of normal endometrium in the proliferative phase and 11 ovarian endometriotic cysts were examined by immunohistochemistry for transforming growth factor‐β1, 2, and 3 isoforms and their type I and II receptors.

RESULTS: Immunoreactivity for all ligands and receptors was detected in both normal endometrium and endometriotic cysts. Isoform‐specific differences in immunostaining were not detected. Expression of all ligands and receptors was significantly increased in epithelial cells of endometriotic cysts compared with those of normal endometrium. On the other hand, stromal cells in normal endometrium and endometriotic cysts were only faintly immunostained. Inflammatory cells infiltrating among endometriotic stromal cells contained the highest immunostaining intensity for all ligands and receptors. We identified nearly all inflammatory cells as macrophages using a specific antibody.

CONCLUSIONS: These findings suggest that macrophages in endometriotic tissue are a major source of transforming growth factor‐β, which may be an important regulator of cell proliferation in endometriotic cysts through paracrine and autocrine actions.
Effect of Neonatal Treatment with a GnRH Antagonist on Development of the Cell‐Mediated Immune Response in Marmosets
Authors: Mann David R. , Lunn Stephen F. , Akinbami Mukaila A. , Samuel Kay , Waterfall Martin , Fraser Hamish M.
Published: September 2011

PROBLEM: We examined the effect of neonatal treatment with a gonadotropin‐releasing hormone (GnRH) antagonist (antide) on the development of cell‐mediated immunity in male marmosets.

METHOD OF STUDY: Neonatal marmoset twins were treated with either vehicle or antide, and the proliferative response (PR) of lymphoid tissue to mitogens was assessed during infancy, the peripubertal period, and adulthood.

RESULTS: Basal proliferation of peripheral blood mononuclear cells (PBMC) from treated peripubertal twins was elevated above control values, but the PR of the cells to T and B cell mitogens was subnormal. Conversely, PBMC from treated infants exhibited an enhanced PR to some of the mitogens employed. In vitro culturing of thymocytes (control or treated) from the three developmental stages with either antide or a GnRH agonist increased basal proliferation, but decreased the PR to mitogens by 60–80%.

CONCLUSION: Neonatal treatment with antide alters development of, but does not permanently impair, cell‐mediated immunity in the marmoset. GnRH appears to modulate immune responses throughout development in the primate.
Biomimetic approach to extensive fracture of anterior teeth – a case report
Authors: da Fonseca João T. A. F. , Reis José A. A. , Ribeiro Carlos M. Z. F.
Published: September 2011

Abstract –  The fracture of anterior teeth in children and adolescents is a common injury. When most tooth structure is compromised and the broken fragment is not recovered, its restoration can become rather complex to both dentist and dental technician. Restoration of single anterior elements is one of the most demanding challenges in fixed prosthodontics. This article describes a clinical case of a 13‐year‐old patient with an extensive fractured central incisor and contra lateral incisor. Endodontic treatment was performed on both teeth, and a temporary removable appliance was made for esthetics. One month later, an indirect esthetic post and core was made for each tooth, and provisionals were placed. After a 6‐month period of soft tissue stabilization, two pressed all‐ceramic crowns were fabricated and bonded to the preparations. The authors believe this to be a stable long‐term option relative to the reminiscent tooth structure, esthetic demand, and occlusal features of the case.
Attenuated Salmonella enteritidis E23 as a vehicle for the rectal delivery of DNA vaccine coding for HIV‐1 polyepitope CTL immunogen
Authors: Karpenko Larisa I. , Danilenko Alexey V. , Bazhan Sergei I. , Danilenko Elena D. , Sysoeva Galina M. , Kaplina Olga N. , Volkova Olga Y. , Oreshkova Svetlana F. , Ilyichev Alexander A.
Published: September 2011

This study is focusing on elucidation of the capacity of attenuated Salmonella enteritidis E23 (cya, crp) to serve as a vehicle for the rectal delivery of the DNA vaccine. Earlier for creation HIV‐1 candidate DNA vaccine we have designed the polyepitope protein TCI (T‐cell immunogen), which comprises over 80 CTL epitopes from subtype A, B and C HIV‐1 proteins. The gene coding for TCI protein was used to construct the eukaryotic expression plasmid pcDNA‐TCI. The attenuated S. enteritidis E23 was transformed by electroporation with recombinant plasmid pcDNA‐TCI and the expression of the TCI gene was determined in vitro and in vivo. BALB/c mice were rectally immunized with S. enteritidis E23/pcDNA‐TCI (108 cfu) twice at 4 week interval. Bacteria were not pathogenic for mice and spontaneously eliminated from mice spleen and liver to 60 days post the immunization. Detectable antibodies were generated in 2 weeks after immunization and their level increased after second immunization. The results of INF‐γ ELISpot show that mice immunized with S. enteritidis E23/pcDNA‐TCI elicited HIV‐specific cellular immune response. This study demonstrates that attenuated S. enteritidis E23 is an effective live vector for rectal delivery of the DNA vaccine pcDNA‐TCI to generate humoral and T‐cellular responses against HIV‐1.
Comparison of the Performance of Statistical Models in Forecasting Monthly Total Dissolved Solids in the Rio Grande1
Authors: Abudu Shalamu , King J. Phillip , Sheng Zhuping
Published: September 2011

Abudu, S., J.P. King, Z. Sheng, 2011. Comparison of the Performance of Statistical Models in Forecasting Monthly Total Dissolved Solids in the Rio Grande. Journal of the American Water Resources Association (JAWRA) 48(1): 10‐23. DOI: 10.1111/j.1752‐1688.2011.00587.x

Abstract:  This paper presents the application of autoregressive integrated moving average (ARIMA), transfer function‐noise (TFN), and artificial neural networks (ANNs) modeling approaches in forecasting monthly total dissolved solids (TDS) of water in the Rio Grande at El Paso, Texas. Predictability analysis was performed between the precipitation, temperature, streamflow rates at the site, releases from upstream reservoirs, and monthly TDS using cross‐correlation statistical tests. The chi‐square test results indicated that the average monthly temperature and precipitation did not show significant predictability on monthly TDS series. The performances of one‐ to three‐month‐ahead model forecasts for the testing period of 1984‐1994 showed that the TFN model that incorporated the streamflow rates at the site and Caballo Reservoir release improved monthly TDS forecasts slightly better than the ARIMA models. Except for one‐month‐ahead forecasts, the ANN models using the streamflow rates at the site as inputs resulted in no significant improvements over the TFN models at two‐month‐ahead and three‐month‐ahead forecasts. For three‐month‐ahead forecasts, the simple ARIMA showed similar performance compared to all other models. The results of this study suggested that simple deseasonalized ARIMA models could be used in one‐ to three‐month‐ahead TDS forecasting at the study site with a simple, explicit model structure and similar model performance as the TFN and ANN models for better water management in the Basin.
Preferred surgical procedure for posterior mediastinal neurogenic tumor
Authors: Zhang Zhenrong , Liu Deruo , Guo Yongqing , Shi Bin , Tian Yanchu , Song Zhiyi , Liang Chaoyang
Published: September 2011

Aim:  To compare the outcomes of video‐assisted thoracoscopic surgery (VATS) with those of thoracotomy for the removal of posterior mediastinal neurogenic tumors.

Methods:  Twenty‐four patients were enrolled in the VATS group and 29 were enrolled in thoracotomy group between 1996 and 2010.

Results:  When compared with the thoracotomy group, patients in the VATS group had a shorter operation time (90 ± 29 min vs. 136 ± 41 min, P < 0.001), less blood loss (42 ± 12 mL vs. 209 ± 162 mL, P < 0.001), shorter time to extubation and discharge (2.5 ± 0.7 days vs. 3.1 ± 1.0 days, P= 0.027; 3.6 ± 0.6 days vs. 4.1 ± 1.0 days, P= 0.045).

Conclusion:  VATS is a safe and effective surgical procedure for posterior mediastinal neurogenic tumors with better outcomes than thoracotomy.
Biomechanical Assessment of a PEEK Rod System for Semi-Rigid Fixation of Lumbar Fusion Constructs
Authors: Gornet Matthew F. , Chan Frank W. , Coleman John C. , Murrell Brian , Nockels Russ P. , Taylor Brett A. , Lanman Todd H. , Ochoa Jorge A.
Published: September 2011

The concept of semi-rigid fixation (SRF) has driven the development of spinal implants that utilize nonmetallic materials and novel rod geometries in an effort to promote fusion via a balance of stability, intra- and inter-level load sharing, and durability. The purpose of this study was to characterize the mechanical and biomechanical properties of a pedicle screw-based polyetheretherketone (PEEK) SRF system for the lumbar spine to compare its kinematic, structural, and durability performance profile against that of traditional lumbar fusion systems. Performance of the SRF system was characterized using a validated spectrum of experimental, computational, and in vitro testing. Finite element models were first used to optimize the size and shape of the polymeric rods and bound their performance parameters. Subsequently, benchtop tests determined the static and dynamic performance threshold of PEEK rods in relevant loading modes (flexion-extension (F/E), axial rotation (AR), and lateral bending (LB)). Numerical analyses evaluated the amount of anteroposterior column load sharing provided by both metallic and PEEK rods. Finally, a cadaveric spine simulator was used to determine the level of stability that PEEK rods provide. Under physiological loading conditions, a 6.35 mm nominal diameter oval PEEK rod construct unloads the bone-screw interface and increases anterior column load (approx. 75% anterior, 25% posterior) when compared to titanium (Ti) rod constructs. The PEEK construct’s stiffness demonstrated a value lower than that of all the metallic rod systems, regardless of diameter or metallic composition (78% < 5.5 mm Ti; 66% < 4.5 mm Ti; 38% < 3.6 mm Ti). The endurance limit of the PEEK construct was comparable to that of clinically successful metallic rod systems (135N at 5 × 106 cycles). Compared to the intact state, cadaveric spines implanted with PEEK constructs demonstrated a significant reduction of range of motion in all three loading directions (> 80% reduction in F/E, p < 0.001; > 70% reduction in LB, p < 0.001; > 54% reduction in AR, p < 0.001). There was no statistically significant difference in the stability provided by the PEEK rods and titanium rods in any mode (p = 0.769 for F/E; p = 0.085 for LB; p = 0.633 for AR). The CD HORIZON® LEGACY™ PEEK Rod System provided intervertebral stability comparable to currently marketed titanium lumbar fusion constructs. PEEK rods also more closely approximated the physiologic anteroposterior column load sharing compared to results with titanium rods. The durability, stability, strength, and biomechanical profile of PEEK rods were demonstrated and the potential advantages of SRF were highlighted.
Effect of Spinal Level and Loading Conditions on the Production of Vertebral Burst Fractures in a Porcine Model
Authors: Boisclair Dominic , Mac-Thiong Jean-Marc , Parent Stefan , Petit Yvan
Published: September 2011

Vertebral burst fractures are commonly studied with experimental animal models. There is however a lack of consensus as to what parameters are important to create an unstable burst fracture with a significant canal encroachment on such model. This study aims to assess the effect of the loading rate, flexion angle, spinal level, and their interactions on the production of a vertebral thoracolumbar burst fracture on a porcine model. Sixteen functional spinal units composed of three vertebrae were harvested from mature Yucatan minipigs. Two loading rates (0.01 and 500 mm/s), two flexion angles (0° and 15°), and two spinal levels (T11-T13 and T14-L2) were studied, following a full factorial experimental plan with one repetition. Compression was applied to each functional unit to create a vertebral fracture. The load-to-failure, loss of compressive stiffness, final canal encroachment, and fracture type were used as criteria to evaluate the resulting fracture. All specimens compressed without flexion resulted in burst fractures. Half of the specimens compressed with the 15° flexion angle resulted in compression fractures. Specimens positioned without flexion lost more of their compressive stiffness and had more significant canal encroachment. Fractured units compressed with a higher loading rate resulted in a greater loss of compressive stiffness. The spinal level had no significant effect on the resulting fractures. The main parameters which affect the resulting fracture are the loading rate and the flexion angle. A higher loading rate and the absence of flexion favors the production of burst fractures with a greater canal encroachment.
A Gimbal-Mounted Pressurization Chamber for Macroscopic and Microscopic Assessment of Ocular Tissues
Authors: Keyes Joseph T. , Yan Dongmei , Rader Jacob H. , Utzinger Urs , Vande Geest Jonathan P.
Published: September 2011

The biomechanical model of glaucoma considers intraocular pressure-related stress and resultant strain on load bearing connective tissues of the optic nerve and surrounding peripapillary sclera as one major causative influence that effects cellular, vascular, and axonal components of the optic nerve. By this reasoning, the quantification of variations in the microstructural architecture and macromechanical response of scleral shells in glaucomatous compared to healthy populations provides an insight into any variations that exist between patient populations. While scleral shells have been tested mechanically in planar and pressure-inflation scenarios the link between the macroscopic biomechanical response and the underlying microstructure has not been determined to date. A potential roadblock to determining how the microstructure changes based on pressure is the ability to mount the spherical scleral shells in a method that does not induce unwanted stresses to the samples (for instance, in the flattening of the spherical specimens), and then capturing macroscopic and microscopic changes under pressure. Often what is done is a macroscopic test followed by sample fixation and then imaging to determine microstructural organization. We introduce a novel device and method, which allows spherical samples to be pressurized and macroscopic and microstructural behavior quantified on fully hydrated ocular specimens. The samples are pressurized and a series of markers on the surface of the sclera imaged from several different perspectives and reconstructed between pressure points to allow for mapping of nonhomogenous strain. Pictures are taken from different perspectives through the use of mounting the pressurization scheme in a gimbal that allows for positioning the sample in several different spherical coordinate system configurations. This ability to move the sclera in space about the center of the globe, coupled with an upright multiphoton microscope, allows for collecting collagen, and elastin signal in a rapid automated fashion so the entire globe can be imaged.
The Effects of Wind and Posture on the Aerodynamic Performance During the Flight Stage of Skiing
Authors: Chen Zhifeng , Fang Haisheng
Published: September 2011

Numerical simulation is conducted to evaluate the wind and posture effects on the aerodynamic performance of a skier during the flight stage. Both steady and unsteady models are applied on a 2D geometry. Using the Fluent code, the fundamental equations of fluid flow are solved simultaneously. In particular we focus on the influence of wind speed and direction on aerodynamic forces with several different postures of the skier in steady modeling. For a chosen case, the unsteady models are used to predict the transient characteristics of streamline distributions and aerodynamic forces. It is found that the skier’s postures, wind speed, and direction play a significant role. The wind condition affects the pressure force (the form drag) on the skier and makes it a resistance or thrust regarding wind directions. The optimized posture with a minimization of resistance under a facing wind is determined as a moving-forward body of the skier. The unsteady modeling reveals that the wake around the skier and aerodynamic forces are strongly dependent on time. This initial study not only provides a qualitative and theoretical basis for the athletes to understand the effects of wind and postures, and then to optimize their postures according to the wind condition during the flight stage of skiing, but also builds the foundation for the systematic study of skiing process with more advanced CFD models in the future.
Hermitian Splines for Modeling Biological Soft Tissue Systems That Exhibit Nonlinear Force-Elongation Curves
Authors: Martel F. , Denninger M. , Langelier E. , Turcotte M-C. , Rancourt D.
Published: September 2011

Numerical simulation of soft tissue mechanical properties is a critical step in developing valuable biomechanical models of live organisms. A cubic Hermitian spline optimization routine is proposed in this paper to model nonlinear experimental force-elongation curves of soft tissues, in particular when modeled as lumped elements. Boundary conditions are introduced to account for the positive definiteness and the particular curvature of the experimental curve to be fitted. The constrained least-square routine minimizes user intervention and optimizes fitting of the experimental data across the whole fitting range. The routine provides coefficients of a Hermitian spline or corresponding knots that are compatible with a number of constraints that are suitable for modeling soft tissue tensile curves. These coefficients or knots may become inputs to user-defined component properties of various modeling software. Splines are particularly advantageous over the well-known exponential model to account for the traction curve flatness at low elongations and to allow for more flexibility in the fitting process. This is desirable as soft tissue models begin to include more complex physical phenomena.
Effective Removal of HCl and SO2 With Dry Injection of Sodium Bicarbonate or Trona
Authors: Kong Yougen , Balland Jean-Pascal
Published: September 2011

The newly promulgated EPA MACT rules for solid waste incinerators require HCl to be mitigated to extremely low concentrations. Most existing air pollution control systems will probably not be able to satisfy these very low limits. To meet the new challenges, dry injection of sodium bicarbonate or trona is a low-cost solution that can be applied in the following situations: (1) Replace existing acid gas mitigation systems; (2) Supplement existing systems; (3) Install where no acid gas mitigation systems exist yet. In a dry sorbent injection system, sodium bicarbonate or trona is injected directly into hot flue gas. After injection, the sorbent is calcined into porous activated sodium carbonate. Its high surface area enables fast gas-solid reactions between acid gases (mainly HCl and SO2) and Na2CO3 to form NaCl and Na2SO4 which are collected by either electrostatic precipitators (ESP) or fabric filters. The dry injection systems with sodium bicarbonate have shown over 99% removal of HCl and 95% removal of SO2 at over 150 Waste-To-Energy plants in Europe. This paper will describe the concept of dry sorbent injection system with sodium bicarbonate or trona, provide performance data from several plants, and describe system design guidelines.
The Technical and Economic Considerations for Extracting Metals From Ash at Waste-to-Energy (WTE) Facilities: Go or No Go!
Authors: White Thomas M. , Nederveld David L.
Published: September 2011

The past few years have produced significant variations in the U.S. economic climate. In turn, the revenues from the extraction and sale of both ferrous and non-ferrous metals from WTE plants have experienced wildly positive/negative swings in value. The revenue from sales of these metals and the capital costs for the process installation directly impacts financial payback, and answers the simple question: “should we do this project?” Some key criteria will be discussed: source reduction and curbside recycling and their impact on metals yield (projected vs. actual), plant size and “economy of scale”, and operating and maintenance costs. This paper will review six recent and planned metals recovery projects in the U.S. Technologies and scopes of work include simple addition of metals recovery equipment, complete systems and buildings at existing facilities, and planned systems and buildings at new facilities. The paper will summarize the criteria for metals revenue and project costs, which determine whether the project is a “Go” or a “No Go”.
Mixing and Residence Time Analysis of Municipal Solid Waste Particles by Different Numbers of Moving Bars and Reciprocation Speeds of a Grate System
Authors: Nakamura Masato R. , Castaldi Marco J.
Published: September 2011

The grate systems of waste-to-energy (WTE) mass-burn combustion chambers, which historically stem from coal combustion technology, have an important role in controlling the mixing of heterogeneous MSW during the combustion process. They are designed for providing efficient flow and mixing of Municipal Solid Waste (MSW) in the combustion chamber. This study presents results from a numerical analysis for grate design and chamber operation, i.e., number of reciprocating bars and reciprocation speed that influence the degree of mixing and residence time of MSW particles. A particle-based bed model of MSW and a physical model of reverse-acting grate were used in order to quantify the mixing diffusion coefficient of MSW particles. We analyzed the particle mixing with different parameters: particle size (d = 6–22 cm diameter), reciprocation speed of moving bars (Rr = 0–90 recip./h), and number of moving bars (Nb = 1–16 bars). According to the size segregation in the particle mixing process in the MSW bed, the undersized waste particles in the MSW bed on the reverse-acting grate have a higher diffusion coefficient than those of oversized and mean size particles. Also the number of moving bars, Nb, as well as reciprocation speed, Rr, were quantitatively related to a diffusion coefficient equation for MSW particle mixing.
TOPOGRAPHICAL EVOLUTION OF MAGNETRON SPUTTERING Ti THIN FILMS DURING OXIDATION OBSERVED BY AFM
Authors: LI XINYUE , JIN YONGZHONG , LIU DONGLIANG , ZENG XIANGUANG , YANG RUISONG
Published: September 2011

Titanium films of 120 nm thickness were magnetron sputtered on glass substrates at room temperature, and subsequently they were annealed under flowing oxygen atmosphere at different temperatures and time. Atomic force microscopy (AFM) was used to study topographic characteristics of the films, including nucleation, crystalline feature, grain size, clustering and roughening. The initial nucleation of titanium oxides has almost completed during annealing at 300°C for 120 min or 400°C for 30 min. Especially, we have already observed the preferential nucleation and grain growth of titanium oxides on locations that protrude from the surface, as opposed to deep grooves. It is confirmed by AFM characterization that both of annealing temperature and time can hasten the nucleation and grain growth of titanium oxides, but annealing time is less influential than its temperature. The typical crystal transfer from amorphous-like to crystalline state occurs at 300–400°C for 120 min during annealing, but the too low temperature of 200°C does not contribute to the crystal transfer. In addition, higher annealing temperature (600°C) leads to the transformation of crystal texture from globular-like to flaky type. Generally, higher annealing temperature or time can lead to higher film surface roughness through the grooving effect, but the roughness decreases with the increase of annealing time (at 400°C for 90–120 min).
FORMATION MECHANISM OF TITANIUM CARBIDE CRYSTAL IN LASER SYNTHESIZED METAL-CERAMIC COMPOSITE COATING
Authors: DU BAOSHUAI , ZHANG ZHONGWEN , WANG XINHONG , ZOU ZENGDA
Published: September 2011

In situ titanium carbide reinforced iron-based composite coating was deposited on mild carbon steel using laser surface engineering (LSE) with ferrotitanium and graphite as precursor. The microstructure and phase constituents of the deposited coating were characterized. Formation mechanism of titanium carbide crystal in the composite coating was elucidated by correlating the morphology of titanium carbide and the thermal cycle experienced by the precursor during the laser treatment. It was demonstrated that titanium carbide was formed in situ as a result of the metallurgical reaction between ferrotitanium and graphite following a liquid-precipitation route. Different morphologies of titanium carbide crystal (dendrite and fishbone) correspond to the primary and eutectic titanium carbide respectively.
NUMERICAL AND ANALYTICAL SOLUTIONS FOR NATURAL CONVECTION FLOW WITH THERMAL RADIATION AND MASS TRANSFER PAST A MOVING VERTICAL POROUS PLATE BY DQM AND HAM
Authors: TALEBIZADEH P. , MOGHIMI M. A. , KIMIAEIFAR A. , AMERI M.
Published: September 2011

In this paper, the boundary-layer natural convection flow on a permeable vertical plate with thermal radiation and mass transfer is studied when the plate moves in its own plane. A uniform temperature with uniform species concentration at the plate is affected and the fluid is considered to be a gray, absorbing–emitting. A viscous flow model is presented using boundary-layer theory comprising the momentum, energy, and concentration equations, which is solved analytically by means of an excellent method called homotopy analysis method (HAM). First, a comparison between HAM results and those obtained by means of a higher-order numerical method, namely differential quadrature method (DQM), is done. Close agreement of two sets of results indicates the accuracy of the HAM. The velocity, temperature, and concentration distributions are displayed graphically, and a parametric study is performed in which the effect of various parameters on the skin friction, the local Nusselt number (Nn), and the local Sherwood number (Mu) are investigated.
A modeling framework that combines markov models and discrete-event simulation for stroke patient care
Authors: McClean Sally , Barton Maria , Garg Lalit , Fullerton Ken
Published: September 2011

Stroke disease places a heavy burden on society, incurring long periods of hospital and community care. Also stroke is a highly complex disease with heterogeneous outcomes and multiple strategies for therapy and care. In this article we develop a modeling framework that clusters patients with respect to their length of stay (LOS); phase-type models are then used to describe patient flows for each cluster. In most cases, there are multiple outcomes, such as discharge to normal residence, nursing home, or death. We therefore derive a novel analytical model for the distribution of LOS in such situations. A model of the whole care system is developed, based on Poisson admissions to hospital, and results obtained for expected numbers in different states of the system at any time. We can thus describe the whole integrated system of stroke patient care, which will facilitate planning of services. We also use the basic model to build a discrete-event simulation, which incorporates back-up queues to model delayed discharge. Based on stroke patients' data from the Belfast City Hospital, various scenarios are explored with a focus on the potential efficiency gains if LOS, prior to discharge to a private nursing home, can be reduced. Predictions for bed occupancy are also provided. The overall modeling framework characterizes the behavior of stroke patient populations, with a focus on integrated system-wide planning, encompassing hospital and community services. Within this general framework we can develop either analytic or simulation models that take account of patient heterogeneity and multiple care options.
The ABC's of ARGs: Alternate Reality Games for Learning
Authors: Olbrish Koreen
Published: September 2011

An alternate reality game (ARG) is sometimes called a pervasive game or transmedia storytelling. Regardless of what you call it at its core is a game driven by a story with players performing activities that mirror real life, making ARGs a perfect fit for scenario-based learning.
Power management of online data-intensive services
Authors: Meisner David , Sadler Christopher M. , Barroso Luiz André , Weber Wolf-Dietrich , Wenisch Thomas F.
Published: September 2011

Much of the success of the Internet services model can be attributed to the popularity of a class of workloads that we call Online Data-Intensive (OLDI) services. These workloads perform significant computing over massive data sets per user request but, unlike their offline counterparts (such as MapReduce computations), they require responsiveness in the sub-second time scale at high request rates. Large search products, online advertising, and machine translation are examples of workloads in this class. Although the load in OLDI services can vary widely during the day, their energy consumption sees little variance due to the lack of energy proportionality of the underlying machinery. The scale and latency sensitivity of OLDI workloads also make them a challenging target for power management techniques.

We investigate what, if anything, can be done to make OLDI systems more energy-proportional. Specifically, we evaluate the applicability of active and idle low-power modes to reduce the power consumed by the primary server components (processor, memory, and disk), while maintaining tight response time constraints, particularly on 95th-percentile latency. Using Web search as a representative example of this workload class, we first characterize a production Web search workload at cluster-wide scale. We provide a fine-grain characterization and expose the opportunity for power savings using low-power modes of each primary server component. Second, we develop and validate a performance model to evaluate the impact of processor- and memory-based low-power modes on the search latency distribution and consider the benefit of current and foreseeable low-power modes. Our results highlight the challenges of power management for this class of workloads. In contrast to other server workloads, for which idle low-power modes have shown great promise, for OLDI workloads we find that energy-proportionality with acceptable query latency can only be achieved using coordinated, full-system active low-power modes.
Fighting fire with fire
Authors: Biswas Susmit , Tiwari Mohit , Sherwood Timothy , Theogarajan Luke , Chong Frederic T.
Published: September 2011

Local thermal hot-spots in microprocessors lead to worst-case provisioning of global cooling resources, especially in large-scale systems where cooling power can be 50~100% of IT power. Further, the efficiency of cooling solutions degrade non-linearly with supply temperature. Recent advances in active cooling techniques have shown on-chip thermoelectric coolers (TECs) to be very efficient at selectively eliminating small hot-spots. Applying current to a superlattice TEC-film that is deposited between silicon and the heat spreader results in a Peltier effect, which spreads the heat and lowers the temperature of the hot-spot significantly and improves
chip reliability
. In this paper, we propose that hot-spot mitigation using thermoelectric coolers can be used as a
power management mechanism
to allow global coolers to be provisioned for a better worst case temperature leading to substantial savings in cooling power.

In order to quantify the potential power savings from using TECs in data center servers, we present a detailed power model that integrates on-chip dynamic and leakage power sour-ces, heat diffusion through the entire chip, TEC and global cooler efficiencies, and all their mutual interactions. Our multi-scale analysis shows that, for a typical data center, TECs allow global coolers to operate at higher temperatures without degrading chip lifetime, and thus save ~27% cooling power on average while providing the same processor reliability as a data center running at 288K.
Influence of Turbulent Scalar Mixing Physics on Premixed Flame Propagation
Authors: Kolla H. , Swaminathan N.
Published: September 2011

The influence of reactive scalar mixing physics on turbulent premixed flame propagation is studied, within the framework of turbulent flame speed modelling, by comparing predictive
ability of two algebraic flame speed models: one that includes all relevant physics and the other ignoring dilatation effects on reactive scalar mixing. This study is an extension of a previous
work analysing and validating the former model. The latter is obtained by neglecting modelling terms that include dilatation effects: a direct effect because of density change across the
flame front and an indirect effect due to dilatation on turbulence‐scalar interaction. An analysis of the limiting behaviour shows that neglecting the indirect effect alters the flame speed scaling
considerably when is small and the scaling remains
unaffected when is large.
This is evident from comparisons of the two models with experimental data which show that the quantitative difference between the two models is as
high as 66% at but only 4% at . Furthermore, neglecting the direct effect results in a poor prediction of turbulent flame speed for all values of , and both effects are important for practically relevant values of this velocity ratio.