bluuebunny/crossref_metadata_2025 huggingface dataset:
Internal corporate governance and board performance in monitoring roles
Authors: Kamardin Hasnah , Haron Hasnah
Published: November 2011

Purpose

This paper aims to examine the relationship between internal corporate governance mechanisms and board performance in monitoring roles.

Design/methodology/approach

A survey questionnaire was used to gather data on board performance, while annual reports were employed to gather data on internal corporate governance mechanisms. Data for board performance were based on 112 directors who represent the companies.

Findings

Factor analysis extracted two dimensions of monitoring roles: management oversight roles and performance evaluation roles. Non‐independent non‐executive directors and managerial ownership were found to be positively related to both dimensions of monitoring roles, while the multiple directorships of non‐executive directors were negatively related to management oversight roles.

Practical implications

The paper establishes the need for regulators to pay particular attention to multiple directorships, which are commonly practiced in public listed companies. The contribution of non‐independent non‐executive directors rather than independent directors in monitoring roles calls for further research. Regulators need to emphasize the performance evaluation roles of the board of directors (BOD), as much emphasis has been given to management oversight roles.

Originality/value

The study contributes to the literature concerning monitoring roles as it shows that management oversight roles and performance evaluation roles are differentiated. The findings provide an avenue for the contribution of non‐independent non‐executive directors and multiple directorships in monitoring roles.
Effect of international financial reporting standards on financial information quality
Authors: García Jara Elisa , Cuadrado Ebrero Amparo , Eslava Zapata Rolando
Published: November 2011

Purpose

This paper aims to analyze the quality of financial information using financial and economic ratios, assessing if the quality is affected by financial reporting standards. A group of factors that allow proving of the capacity of ratios to measure accounting information quality – and thus facilitating the analysis process to the groups of users – is also determined.

Design/methodology/approach

Using a sample of 111 companies from the Madrid Stock Exchange and 32 from Eurostoxx50, descriptive analysis and non‐parametric variance analysis were carried out during the period 2005‐2007. At the same time, reduction data techniques, specifically principal components analysis (PCA), were performed to detect the underlying main factors for the year 2007.

Findings

There is an indication that financial information quality is affected by financial reporting standards. Additionally, there is a group of factors that show an alternative to analyze accounting information.

Practical implications

This study provides evidence to measure financial information quality and the results can be beneficial to accounting users, as well as contributing to the literature related to this topic.

Originality/value

Empirically, this study shows that accounting information is affected by financial reporting standards.
Surface contact stimulates the just‐in‐time deployment of bacterial adhesins
Authors: Li Guanglai , Brown Pamela J. B. , Tang Jay X. , Xu Jing , Quardokus Ellen M. , Fuqua Clay , Brun Yves V.
Published: November 2011

The attachment of bacteria to surfaces provides advantages such as increasing nutrient access and resistance to environmental stress. Attachment begins with a reversible phase, often mediated by surface structures such as flagella and pili, followed by a transition to irreversible attachment, typically mediated by polysaccharides. Here we show that the interplay between pili and flagellum rotation stimulates the rapid transition between reversible and polysaccharide‐mediated irreversible attachment. We found that reversible attachment of Caulobacter crescentus cells is mediated by motile cells bearing pili and that their contact with a surface results in the rapid pili‐dependent arrest of flagellum rotation and concurrent stimulation of polar holdfast adhesive polysaccharide. Similar stimulation of polar adhesin production by surface contact occurs in Asticcacaulis biprosthecum and Agrobacterium tumefaciens. Therefore, single bacterial cells respond to their initial contact with surfaces by triggering just‐in‐time adhesin production. This mechanism restricts stable attachment to intimate surface interactions, thereby maximizing surface attachment, discouraging non‐productive self‐adherence, and preventing curing of the adhesive.
Colonoscopic high frequency mini‐probe ultrasound is more accurate than conventional computed tomography in the local staging of colonic cancer
Authors: Haji A. , Ryan S. , Bjarnason I. , Donaldson N. , Papagrigoriadis S.
Published: November 2011

Aim  Colonoscopic high frequency mini‐probe ultrasound was compared prospectively with CT in the local staging of colonic cancer.

Method  Consecutive patients undergoing surgical resection for colonic cancer were recruited. Preoperative 64‐slice CT staging with multiplanar reconstruction was compared with colonoscopic high frequency mini‐probe ultrasound using 12 MHz and 20 MHz probes. The three methods of staging (CT, 12 MHz ultrasound and 20 MHz ultrasound) were compared with the histological stage of the resected specimen. This was done using weighted kappa coefficients where weights of 0.7–0.8 were given to penalize disagreements of one level in either direction and weights of zero were given to penalize disagreements of more than one level in any direction.

Results  In total, 38 patients with colonic cancer were included. They were located in the sigmoid (n = 20), descending (n = 5), ascending (n = 2) and transverse colon (n = 1) and in the caecum (n = 7) and splenic (n = 2) and hepatic (n = 1) flexure. Histopathological assessment revealed seven pT1, four pT2, 25 pT3 and two pT4 cancers. In relation to the pathology the weighted kappa coefficients were 0.36 (SE = 0.14), 0.81 (SE = 0.16) and 0.81 (SE = 0.17) for CT, ultrasound 12 MHz and ultrasound 20 MHz. Histopathologically 15 (39.5%) patients were lymph node positive. The sensitivity, specificity and kappa coefficient for detection of nodal disease for CT were 80%, 47.8% and 0.25 (SE = 0.14) compared with 80%, 82.5% and 0.62 for 12 MHz ultrasound (SD = 0.14) and 23%, 90.5% and 0.15 (SD = 0.13) for 20 MHz ultrasound.

Conclusion  Colonoscopic ultrasound is significantly more accurate than CT for T staging of colonic cancers. With respect to nodal status, 12 MHz ultrasound offers superior accuracy to CT or 20 MHz ultrasound.
Low HDL predicts differential blood pressure effects from two weight‐loss approaches: a secondary analysis of blood pressure from a randomized, clinical weight‐loss trial
Authors: Turer C. B. , Bernstein I. H. , Edelman D. E. , Yancy W. S.
Published: November 2011

Examining predictors of blood‐pressure (BP) response to weight‐loss diets might provide insight into mechanisms and help guide clinical care. We examined whether certain baseline patient characteristics (e.g. diet, medical history and laboratory tests) predicted BP response to two weight‐loss diet approaches that differ in macronutrient content. One hundred and forty‐six overweight adult outpatients were randomized to either a low‐carbohydrate diet (N = 72) or orlistat plus a low‐fat diet (N = 74) for 48 weeks. Predictors of BP reduction were evaluated using a structured approach and random effects regression models. Participants were 56% African‐American, 72% male and 53 (±10) years‐old. Of the variables considered, low baseline high‐density lipoprotein (HDL) predicted greater reduction in BP in those patients who received the low‐carbohydrate diet (p = 0.03 for systolic BP; p = 0.03 for diastolic BP and p = 0.02 for mean arterial pressure). A low HDL level may identify patients who will have greater BP improvement on a low‐carbohydrate diet.
Summer–winter switching of the Ramadan fasts in people with diabetes living in temperate regions
Authors: Ghouri N. , Gatrad R. , Sattar N. , Dhami S. , Sheikh A.
Published: November 2011

Diabet. Med. 29, 696–697 (2012)
QTc prolongation and diabetes therapies
Authors: Watters K. , Munro N. , Feher M.
Published: November 2011

Diabet. Med. 29, 290–292 (2012)
Resolution of leucocyte‐mediated mucosal diseases. A novel in vivo paradigm for drug development
Authors: Persson Carl , Uller Lena
Published: November 2011

Removal of disease‐driving inflammatory leucocytes is central to resolution of inflammation. The current pharmacological dogma teaches leucocyte elimination through apoptosis followed by phagocytosis. However, actual resolving roles of apoptotic–phagocytic processes have been difficult to demonstrate in the major diseases that are characterized by mucosal tissue inflammation. Many current in vivo observations rather demonstrate that leucocyte elimination occurs by transepithelial locomotion. Findings in diseased gut and bladder mucosae support this notion. Respiratory disease data are particularly compelling. Eosinophils and neutrophils abound in sputum and tracheal aspirates during treatment‐induced recovery from severe asthma. Prolonged sputum neutrophilia, along with clinical improvement, follows upon smoking cessation in COPD. Eosinophils, neutrophils, lymphocytes, mast cells and dendritic cells also move in large numbers into the bronchial lumen at spontaneous inflammation resolution following allergen challenge in allergic rhinitis and asthma. A corresponding reduction of infiltrated cells in the bronchial mucosal tissue demonstrates efficiency of the transepithelial elimination pathway. Underscoring its operational role, drugs impeding transepithelial elimination of leucocytes aggravate mucosal/parenchymal inflammation. Hence, relying on lumen cell data alone can lead to paradoxical conclusions regarding anti‐inflammatory drug efficacy. Conversely, drugs promoting non‐injurious transepithelial elimination of leucocytes could resolve mucosal inflammatory diseases.
Functional consequences of human airway smooth muscle phenotype plasticity
Authors: Dekkers Bart GJ , Bos I Sophie T , Zaagsma Johan , Meurs Herman
Published: November 2011

BACKGROUND AND PURPOSE Airway smooth muscle (ASM) phenotype plasticity, characterized by reversible switching between contractile and proliferative phenotypes, is considered to contribute to increased ASM mass and airway hyper‐responsiveness in asthma. Further, increased expression of collagen I has been observed within the ASM bundle of asthmatics. Previously, we showed that exposure of intact bovine tracheal smooth muscle (BTSM) to collagen I induces a switch from a contractile to a hypocontractile, proliferative phenotype. However, the functional relevance of this finding for intact human ASM has not been established.

EXPERIMENTAL APPROACH We investigated the effects of exposure of human tracheal smooth muscle (HTSM) strips to monomeric collagen I and PDGF on contractile responses to methacholine and KCl. Expression of contractile proteins sm‐α‐actin and sm‐MHC was assessed by Western blot analysis. The proliferation of HTSM cells was assessed by cell counting, measuring mitochondrial activity (Alamarblue conversion) and [3H]‐thymidine incorporation. Proliferation of intact tissue slices was assessed by [3H]‐thymidine incorporation.

KEY RESULTS Culturing HTSM strips in the presence of collagen I or PDGF for 4 days reduced maximal contractile responses to methacholine or KCl and the expression of contractile proteins. Conversely, collagen I and PDGF increased proliferation of HTSM cells and proliferative responses in tissue slices. PDGF additively increased the proliferation of HTSM cells cultured on collagen I; this additive effect was not observed on contractility, contractile protein expression or proliferation of intact tissue.

CONCLUSION AND IMPLICATIONS These findings indicate that collagen I and PDGF induce a functionally hypocontractile, proliferative phenotype of human ASM, which may contribute to airway remodelling in asthma.
Atrial Dysfunction and Interatrial Dyssynchrony Predict Atrial High Rate Episodes: Insight into the Distinct Effects of Right Atrial Appendage Pacing
Authors: XIE JUN‐MIN , FANG FANG , ZHANG QING , CHAN JOSEPH Y.‐S. , YIP GABRIEL W.‐K. , SANDERSON JOHN E. , LAM YAT‐YIN , YAN BRYAN P.‐Y. , YU CHEUK‐MAN
Published: November 2011

Atrial Dysfunction and Dyssynchrony Predict Atrial High Rate Episodes.

Introduction: Right atrial (RA) appendage pacing may prolong atrial conduction time (ACT). This study aimed to investigate if RA appendage pacing can induce intra‐ and interatrial dyssynchrony and if atrial dysfunction and dyssynchrony can predict atrial high rate episodes (AHREs) in the first year after pacing.

Methods and Results: Patients implanted with dual‐chamber pacemakers for symptomatic bradycardia were enrolled. Cumulative percentage of RA appendage pacing (Cum%AP) during 1‐year follow‐up and AHREs were recorded. Full Doppler echocardiography studies were performed before implantation and 1 year after pacing. ACT and peak atrial velocities (Sm‐la, Em‐la, Am‐la) were measured. One hundred ten patients (age 70.5 ± 11 years; 53 males) were recruited and completed 1‐year follow‐up. ACT of both RA and left atrial (LA) were more prolonged in patients with Cum%AP > 75% than those with <25%. Intra‐ and interatrial dyssynchrony was more obvious in patients with Cum%AP > 75% (22.3 ± 12.2 milliseconds vs 9.5 ± 6.2 milliseconds; 53.9 ± 29.7 milliseconds vs 19.7 ± 17.3 milliseconds; both P < 0.001). AHREs occurred in 29% of patients. Atrial pump function and interatrial dyssynchrony independently predicted AHREs in multivariate analysis. Receiver operating characteristic curve provided a cutoff value of Am‐la <5.3 cm/s, which predicted AHREs with a sensitivity of 71% and a specificity of 75% (area under the curve, 0.822; P < 0.001).

Conclusion: RA appendage pacing causes atrial conduction delay with intra‐ and interatrial dyssynchrony. Atrial dysfunction and interatrial dyssynchrony are related to AHREs in the first year after pacing.
Evaluating Correlation‐Based Metric for Surrogate Marker Qualification within a Causal Correlation Framework
Authors: Wang Yue , Mogg Robin , Lunceford Jared
Published: November 2011

Summary Biomarkers play an increasing role in the clinical development of new therapeutics. Earlier clinical decisions facilitated by biomarkers can lead to reduced costs and duration of drug development. Associations between biomarkers and clinical endpoints are often viewed as initial evidence supporting the intended purpose. As a result, even though it is widely understood that correlation is not proof of a causal relationship, correlation continues to be used as a metric for biomarker qualification in practice. In this article, we introduce a causal correlation framework where two different types of correlations are defined at the individual level. We show that the correlation estimate is a composite of different components, and needs to be interpreted with caution when used for biomarker qualification to avoid misleading conclusions. Otherwise, a significant correlation can be concluded even in the absence of a true underlying association. We also show how the causal quantities of interest are testable in a crossover design and provide discussion on the challenges that exist in a parallel group setting.
Pain in neonatal intensive care: role of melatonin as an analgesic antioxidant
Authors: Gitto Eloisa , Aversa Salvatore , Salpietro Carmelo Damiano , Barberi Ignazio , Arrigo Teresa , Trimarchi Giuseppe , Reiter Russel J. , Pellegrino Salvatore
Published: November 2011

Abstract:  Endotracheal intubation is a common painful procedure in newborn care. Neonates are more sensitive to pain than older infants, children, and adults, and this hypersensitivity is further exacerbated in preterm neonates. The aim of this study was to evaluate the analgesic activity of melatonin during endotracheal intubation of the newborn by using the Neonatal Infant Pain Scale (NIPS) and Premature Infant Pain Profile (PIPP) score. Secondary outcome was an evaluation of melatonin as inflammatory responses. This was performed by measuring the levels of pro‐ and anti‐inflammatory cytokines implicated in the pain. Sixty preterm infants were enrolled in the study and were randomly divided into two groups: 30 infants treated with melatonin plus common sedation and analgesia recommended by Italian Society of Neonatology (group 1) and 30 infants treated with only common sedation and analgesia. The sedative and analgesic drugs included atropine, fentanyl, and vecuronium. The reduction in pain score (NIPS) was similar in both groups at an early phase, while it (PIPP score) was lower in melatonin‐treated group infants than the other newborns at a late phase, during intubation and mechanical ventilation. The differences were statistically significant at 12, 24, 48, and 72 hr (P < 0.001). Pro‐inflammatory and anti‐inflammatory cytokines (IL‐6, IL‐8, IL‐10 and IL‐12) were higher in the common sedation and analgesia group than in melatonin‐treated infants at 24, 48, 72 hr and 7 days (P < 0.001). This study suggests the use of melatonin as an adjunct analgesic therapy during procedural pain, especially when an inflammatory component is involved.
Causes of neonatal death: results from NeoKIP community‐based trial in Quang Ninh province, Vietnam
Authors: Nga Nguyen Thu , Hoa Dinh Thi Phuong , Målqvist Mats , Persson Lars‐Åke , Ewald Uwe
Published: November 2011

Aim:  To ascertain the causes of neonatal death in a province in northern Vietnam and analyse their distribution over age at death, birth weight and place of delivery.

Methods:  Verbal autopsy interviews using a questionnaire derived from WHO standard and adapted to Vietnamese conditions was performed on all neonatal deaths occurring in Quang Ninh province from July 2008 to June 2010. Three experienced paediatricians independently reviewed all verbal autopsy records (233) and assigned a main cause of death. In case of disagreement in the allocation of cause of death, a consensus process was initiated to decide on a final cause.

Results:  Neonatal mortality rate within the study area was 16/1000 (238 neonatal deaths and 14 453 live births) over the study period. Prematurity/low birth‐weight (37.8%), intrapartum‐related neonatal deaths (birth asphyxia, 33.2%), infections (13.0%) and congenital malformation (6.7%) were the four leading causes of death. Four cases of neonatal tetanus were found. Intrapartum‐related deaths dominated in the home delivery group, whereas prematurity was the most prominent cause of death at all facility levels. Most neonatal deaths occurred within the first 24 h after delivery (58.6%).

Conclusion:  A high proportion of deaths due to prematurity and intrapartum‐related causes, calls for improvements of delivery care and resuscitation practices at health facilities.
The regulation of N‐methyl‐d‐aspartate receptors by Src kinase
Authors: Groveman Bradley R. , Feng Shuang , Fang Xiao‐Qian , Pflueger Melissa , Lin Shuang‐Xiu , Bienkiewicz Ewa A. , Yu XianMin
Published: November 2011

Src family kinases (SFKs) play critical roles in the regulation of many cellular functions by growth factors, G‐protein‐coupled receptors and ligand‐gated ion channels. Recent data have shown that SFKs serve as a convergent point of multiple signaling pathways regulating N‐methyl‐d‐aspartate (NMDA) receptors in the central nervous system. Multiple SFK molecules, such as Src and Fyn, closely associate with their substrate, NMDA receptors, via indirect and direct binding mechanisms. The NMDA receptor is associated with an SFK signaling complex consisting of SFKs; the SFK‐activating phosphatase, protein tyrosine phosphatase α; and the SFK‐inactivating kinase, C‐terminal Src kinase. Early studies have demonstrated that intramolecular interactions with the SH2 or SH3 domain lock SFKs in a closed conformation. Disruption of the interdomain interactions can induce the activation of SFKs with multiple signaling pathways involved in regulation of this process. The enzyme activity of SFKs appears ‘graded’, exhibiting different levels coinciding with activation states. It has also been proposed that the SH2 and SH3 domains may stimulate catalytic activity of protein tyrosine kinases, such as Abl. Recently, it has been found that the enzyme activity of neuronal Src protein is associated with its stability, and that the SH2 and SH3 domain interactions may act not only to constrain the activation of neuronal Src, but also to regulate the enzyme activity of active neuronal Src. Collectively, these findings demonstrate novel mechanisms underlying the regulation of SFKs.
Acid inhibition effect of ilaprazole on Helicobacter pylori‐negative healthy volunteers: An open randomized cross‐over study
Authors: DU Yi Qi , GUO Wen Yuan , ZOU Duo Wu , ZHAN Xian Bao , LI Zhen , HU Jin Hong , GONG Yan Fang , HE Jia , LU Jian Ping , LI Zhao Shen
Published: November 2011

OBJECTIVE:  The aim of this study was to evaluate the effects and safety of different doses of ilaprazole on healthy volunteers without a Helicobacter pylori infection.

METHODS:  A total of 12 healthy Chinese volunteers were enrolled and divided into four groups randomly, with a 5‐day treatment of oral ilaprazole 5 mg, 10 mg and 20 mg or omeprazole 20 mg, respectively. After an interval of a 14‐day washout phase, each was switched to another dose group and eventually completed all four regimens. The percentage time of intragastric pH > 4 was the major index. The polymorphisms of the metabolic enzyme CYP2C19 in these volunteers were also detected.

RESULTS:  The percentage time of intragastric pH > 4 in the ilaprazole 5, 10 and 20 mg groups were 80.4%, 88.1% and 91.0%, respectively, during the first 24 h, compared to that of the 20 mg omeprazole group (76.6%, P > 0.05). Ilaprazole 20 mg provided a significant higher mean 24‐h pH than that of the same dose of omeprazole both on Day 1 (7.78 vs 6.67, P < 0.01) and Day 5 (7.95 vs 7.44, P < 0.05). No CYP2C19‐dependent difference or obvious adverse effect were found in any ilaprazole groups.

CONCLUSION:  Low dose ilaprazole offers a gastric acid inhibition comparable to a routine dose of omeprazole, and further investigations in patients with acid‐associated diseases are needed.
Rapid high‐performance liquid chromatography method for determination of tryptophan in gastric juice
Authors: LIAN Wei , MA Dong Jie , XU Xu , CHEN Ying , WU Yun Lin
Published: November 2011

OBJECTIVE:  To develop a rapid, high‐performance liquid chromatography (HPLC) method for the determination of tryptophan in gastric juice to help the differentiation between gastric cancer and benign gastric disease.

METHODS:  HPLC was performed on a restricted access material Shiseido Capcell Pak MF SCX SG80 column. Phosphate buffered solution (90 mmol/L, pH 3.5)‐acetonitrile (ACN; 80/20, V/V) was chosen as the mobile phase. Separation was done at room temperature using a constant flow rate of 1.0 mL/min. Fluorescence emission signal intensity at 330 nm excited by 288 nm ultra violet light was detected and measured.

RESULTS:  Thirty‐eight gastric juice samples from patients with gastric cancer and 48 gastric juice samples of patients with benign gastric disease were tested. A linear relationship in the range of 0.20–100 mg/L was obtained between the concentration of tryptophan and its fluorescence emission signal intensity at 330 nm. The limit of detection was 0.05 mg/L. The recovery rate was 77.4–90.6%.

CONCLUSIONS:  An HPLC method based on strong cation‐exchange restricted access columns for determination of concentration of tryptophan in gastric juice was developed. The method has excellent precision and stability. It is compatible with the analysis of gastric juice and has the potential to be used for gastric cancer screening.
Evaluating Mastery of Biostatistics for Medical Researchers: Need for a New Assessment Tool
Authors: Enders Felicity
Published: November 2011

Research training has enabled academic clinicians to contribute significantly to the body of medical research literature. Biostatistics represents a critical methodological skill for such researchers, as statistical methods are increasingly a necessary part of medical research. However, there is no validated knowledge and skills assessment for graduate level biostatistics for academic medical researchers. In this paper, I review graduate level statistical competencies and existing instruments intended to assess physicians’ ability to read the medical literature and for undergraduate statistics for their alignment with core competencies necessary for successful use of statistics. This analysis shows a need for a new instrument to assess biostatistical competencies for medical researchers. Clin Trans Sci 2011; Volume 4: 448–454
Deceit pollination and the effect of deforestation on reproduction in dioecious Schisandra sphenanthera (Schisandraceae) in central China
Authors: DU Wei , HUANG Lan‐Jie , WANG Xiao‐Fan
Published: November 2011

Abstract  The fruits of Schisandra sphenanthera (dioecious) are used to produce ‘Nan‐Wuweizi’, an important Chinese medicine. However, long‐term exploitation and habitat destruction have threatened these plants in nature. Knowledge of the reproductive biology of S. sphenanthera is essential to help formulate a conservation strategy for these plants. Field studies were conducted at Jigong Mountain (JGM) and Jinji Valley (JJV) in Henan and Hubei Provinces, China. The reproductive biology of S. sphenanthera was analyzed at these sites, including population structure, pollination, floral morphology, and natural fruit set. The 11 populations at two sites were male biased. The primary floral visitors were gall midges (Resseliella sp., Cecidomyiidae; Diptera) and thrips (Thrips flavidulus; Thysanoptera). Floral visitor exclusion experiments and pollen load analysis indicate that gall midges are the primary pollinators. Pollen was the only floral reward for the gall midges. Female flowers attracted pollinators using deceit. The natural fruit set ratio in the cut forest site (JJV) was significantly lower than that at the JGM site, where habitats of S. sphenanthera were well preserved. This indicates that the life cycles of S. sphenanthera and the pollinating insects are vulnerable in disturbed (or cut) habitats.
Effects and mechanisms of total Panax notoginseng saponins on proliferation of vascular smooth muscle cells with plasma pharmacology method
Authors: Zhang Wei , Chen Gang , Deng Chang-Qing
Published: November 2011

Objectives

Total Panax notoginseng saponin (TPNS) is extracted from Panax notoginseng. Our previous studies suggested that TPNS could inhibit intimal hyperplasia. This study discussed the impact of TPNS on the proliferation of vascular smooth muscle cells (VSMCs) and revealed the associated mechanisms through cell cycle-related factors and extracellular regulated protein kinase (ERK) signal transduction pathway.

Methods

A VSMC proliferation model induced by platelet-derived growth factor (PDGF) was established to observe the effects of rat drug-containing plasma on VSMC proliferation.

Key findings

After being stimulated by PDGF, the proliferating cell nuclear antigen (PCNA) and c-fos content increased, while up-regulation of cyclinD1, cyclin-dependent kinase-4 (CDK4) and down-regulation of p21 protein were observed. These changes were inhibited by atorvastatin and TSPN drug-containing plasma, and the inhibitive activity in both groups was not significant. Furthermore, both atorvastatin and TSPN could obviously inhibit the activation of PDGF-induced P-ERK1/2 and increase the content of MKP-1, there were also no significant differences.

Conclusions

These results suggested that atorvastatin and TPNS could inhibit VSMC proliferation by inhibiting the activation of ERK signalling pathway.
On Occurrence of Reverse Full Annular Rub
Authors: Yu John J.
Published: November 2011

This paper discusses reverse full annular rub based on a two degree-of-freedom rotor/seal model where a rubbing location can be simulated away from the lumped rotor mass. The analytical model is much closer to the experimental setup for comparison of results, and real machines for analysis, than the previous one degree-of-freedom model. Its closed-form solution is given including reverse rub amplitudes and relative phases, as well as the normal contact force. The exact frequency equation in polynomial form yields reverse full annular rub frequencies without having to neglect any parameters. Many conclusions can be drawn directly from explicit expressions without numerical calculations. The solution with nonpositive normal contact force indicates a dry-friction whirl/whip-free region, usually accompanied by low friction and/or high damping. The analytical study covers both dry-friction whirl and dry-friction whip, and their relations with dry-friction factor, damping, and rotor speed. Range of reverse rub frequencies, their relation with rotor and rotor/seal coupled natural frequencies, and direction of frictional force, are also revealed. Destructive dry-friction whip experimental results are given, which have fully confirmed the analytical formulas.
Integrated Optimization Design for a Radial Turbine Wheel of a 100 kW-Class Microturbine
Authors: Fu Lei , Shi Yan , Deng Qinghua , Li Huaizhi , Feng Zhenping
Published: November 2011

The aerodynamic performance, structural strength, and wheel weight are three important factors in the design process of the radial turbine. This paper presents an investigation on these aspects and develops an optimization design approach for radial turbine with consideration of the three factors. The aerodynamic design for the turbine wheel with an inlet diameter of 230 mm for the 100 kW-class microturbine unit is carried out first as the original design. Then, the cylinder parabolic geometrical design method is applied to the wheel modeling and structural design, but the maximum stress predicted by finite element analysis greatly exceeds the yield limit of material. Further, the wheel weight is above 7.2 kg, thus, bringing some critical difficulties for bearing design and turbine operation. Therefore, an integrated optimization design method for radial turbine is studied and developed in this paper with focus on the wheel design. Meridional profiles and shape lines of the turbine wheel are optimized with consideration of the whole wheel weight. Main structural modeling parameters are reselected to reduce the wheel weight. Trade-off between aerodynamic performance and strength performance is highly emphasized during the optimization design. The results show that the optimized turbine wheel gets high aerodynamic performance and acceptable stress distribution with a weight less than 3.8 kg.
Further Characterization of the Disturbance Field in a Transversely Excited Swirl-Stabilized Flame
Authors: O’Connor Jacqueline , Lieuwen Tim
Published: November 2011

This paper describes an analysis of the unsteady flow field in swirl flames subjected to transverse acoustic waves. This work is motivated by transverse instabilities in annular gas turbine combustors, which are a continuing challenge for both power generation and aircraft applications. The unsteady flow field that disturbs the flame consists not only of the incident transverse acoustic wave, but also longitudinal acoustic fluctuations and vortical fluctuations associated with underlying hydrodynamic instabilities of the base flow. We show that the acoustic and vortical velocity fluctuations are of comparable magnitude. The superposition of these waves leads to strong interference patterns in the velocity field, a result of the significantly different wave propagation speeds and axial phase dependencies of these two disturbance sources. Vortical fluctuations originate from the convectively unstable shear layers and absolutely unstable swirling jet. We argue that the unsteady shear layer induced fluctuations are the most dynamically significant, as they are the primary source of flame fluctuations. We also suggest that vortical structures associated with vortex breakdown play an important role in controlling the time-averaged features of the central flow and flame spreading angle, but do not play an important role in disturbing the flame at low disturbance amplitudes. This result has important implications not only for our understanding of the velocity disturbance field in the flame region, but also for capturing important physics in future modeling efforts.
Design of a Surgical Port for Minimally Invasive Beating-Heart Intracardial Procedures
Authors: DiBiasio Christopher M. , Durand Keith V. , Hopkins Jonathan , Traina Zach , Slocum Alexander H. , Vasilyev Nikolay V. , del Nido Pedro J.
Published: November 2011

Direct-access, minimally invasive, beating-heart intracardial procedures have the potential to replace many traditional surgical procedures requiring cardio-pulmonary bypass as long as micro-emboli are prevented from entering the cardiovascular system. A new surgical port was developed to introduce surgical instruments into chambers of the beating heart during minimally invasive, intracardial surgical procedures without allowing the introduction of micro-emboli 0.1 mm or larger in size. The design consists of an outer port body that is secured to the heart wall using a purse string suture and a series of inner tubular sleeves that form the interface between the port and the transecting instrument. The design enables rapid tool changes and accommodates a wide variety of instruments. The port uses a fluid purging system to dislodge and remove emboli from a surgical instrument. Laboratory and clinical tests show that the port adequately seals around a surgical instrument and prevents the introduction of emboli with diameters greater than 0.1 mm into the heart while minimizing hemorrhage.
SU‐C‐224‐04: Effect of Refraction on Dose Reconstruction in Optical‐CT Gel Dosimetry
Authors: Florescu L , Ambartsoumian G , Wuu C
Published: November 2011

Purpose: Optical‐CT gel/radiochromic dosimetry has emerged as a promising candidate for 3D dose verification. One factor that affects the accuracy of dose reconstruction in this technique is the refractive index mismatch between the gel phantom and the matching liquid that prevents the full width of the phantom from being used for dose mapping. The purpose of this study is to investigate the effect of the refractive artifact on dose reconstruction, and to identify optimal designs for accurate gel dosimeters. Methods: Numerical experiments were carried out for a series of model attenuation coefficients of the gel phantom and various degrees of refraction resulting in situations where only projections through certain central sections of the sample are detected. Measured data was obtained as the Radon transform of the model attenuation coefficient. The attenuation coefficient was then reconstructed using the filtered backprojection algorithm. A mathematical study was performed in the framework of the so‐called interior problem of Radon transform inversion. The variation of the amount of data accessible experimentally with the refractive index mismatch was investigated using geometrical optics. Results: It was demonstrated that the reconstruction of the attenuation coefficient within 3% is possible in the central part of the phantom even if only 82.5% of the optical projections are detected. This fraction of available data results from a 1.5% refractive index mismatch between the gel and liquid. Using a priori knowledge of the value of the absorption coefficient at a given point in the sample, it is possible to calculate the correct value at all points. Conclusions: Optical attenuation and dose in an optical CT gel dosimeter can be reconstructed accurately in the central part of the dosimeter even if only limited data are available. A priori knowledge of the attenuation coefficient at a point in the sample enables almost exact reconstruction.
SU‐C‐224‐11: Investigating the Effects of Using Several Calibration Conditions on the Measurement Accuracy of Plastic Scintillation Detectors
Authors: Klein D , Wootton L , Tailor R , Beddar S
Published: November 2011

Purpose: To investigate the effects of using several conditions (employing assorted radiation field sizes, doses, and depths in water) for the calibration of a plastic scintillation detector (PSD) on measurement accuracy. Methods: The detector system comprised one PSD and a charge‐coupled device (CCD) camera‐based reader system designed to implement the chromatic removal method for discriminating Cerenkov light from scintillation signal. PSD systems of this type are typically calibrated using only two calibration conditions. In this study, we constructed twelve calibration conditions using field sizes of 5×5, 10×10, 20×20, and 30×30 cm2; doses of 10 and 100 cGy; and depths of 2 and 10 cm, with the PSD centered in a water phantom for 60Co irradiation. We used every combination of two or more conditions (up to twelve) to produce 4083 distinct sets of calibration factors via a combinatorial computer algorithm. We tested all calibrations against data taken using a clinical linear accelerator with the PSD placed at water‐equivalent depths of dose maximum and 6.6 cm for 6 MV (setups ‘A’ and ‘B’, respectively) and 18 MV (setups ‘C’ and ‘D’, respectively) photon beams. Results: The most accurate calibration resulted from a combination of four conditions using both depths, field sizes of 10×10 and 30×30 cm2, but all using 10 cGy doses. For setups A, B, C, and D the PSD‐measured dose differed from the known dose by 0.5%, 0.9%, 0.3%, and 0.3% respectively. However, six hundred of the calibrations resulted in differences of <1% between PSD and known doses delivered by the linac across the four test setups Conclusions: This study suggests that the accurate calibration of PSDs is flexible with respect to the number of conditions used, though certain condition combinations should be avoided due to their considerable inadequacy in satisfying the requirements of the chromatic removal method.

This work was supported in part by the National Cancer Institute through a T32 grant (CA119930‐04) and an R01 grant (CA120198‐01A2).
SU‐C‐BRB‐05: Quality Assurance of Gated RapidArc Stereotactic Body Irradiation
Authors: Hsu A , Mok E
Published: November 2011

Purpose: Develop a reproducible QA methodology for commissioning gated RapidArc SBRT and patient treatment. Metrics used for patient specific QA, namely distance‐to‐agreement (DTA) and gamma index, are examined to determine if standard values used for IMRT are applicable for displacementgated treatments. Methods: Methods followed that used for IMRT patient‐specific QA. Slabs of solid water with 1.5 mm radio‐opaque markers were placed on a Respiratory Gating Platform (Standard Imaging), and the phantom was aligned to markers placed on its stationary base. Treatment plans were based on 4D and planning CTs acquired while the phantom was moved sinusoidally. Gating parameters were determined by fluoroscopic imaging prior to treatment. 3D square fields, RapidArc plans with spherical targets (1–10 cm diameter), and patient plans were delivered to the moving phantom with a 1 mm gating aperture. Dose distributions were measured with Kodak EDR2 film and compared to distributions planned with Eclipse v8.9 using RIT 113v5.2 software to determine the mean DTA. Results: For square fields the DTA averaged over the different field sizes was 3.4 mm in the direction parallel to the motion and 2.7 mm perpendicular. The average 2D DTA was 3.8 mm. For the gated RapidArc treatments, the average DTAs were 3.4 mm parallel to the motion and 1.9 mm perpendicular. The 2D DTA was 3.0 mm. There was a trend for the DTA for small targets to be larger than for large targets. For the patient plan the 2D DTA for the gated treatment was 2.6 mm, and 0.3 mm with the phantom static. Conclusions: A repeatable QA method for gated RapidArc SBRT has been implemented. With a fluoroscopic gating aperture of 1 mm, use of a gamma index criterion of (3%, 3 mm) and a DTA of 3 mm is valid for small targets with gated delivery.
SU‐C‐BRC‐05: RT Analytics: Prior‐Knowledge Treatment Planning Using Image‐ Based Database Mining
Authors: Fox T , Schreibmann E , Jani A
Published: November 2011

Purpose: The purpose of this work was to create prospective treatment plans based on anatomical feature matching to previously treated cases from the institution database. This tool recommends ideal treatment plans to clinicians and provides quality control (QC) of the plan generation process to ensure best practices based on past planning experiences. Methods: An image‐based and feature‐selection search engine (RT‐Analytics) was implemented that explores previously treated cases of similar anatomy, returning a list of suggested plan configurations and corresponding DVHs. The search is based on a multi‐modality image registration to match isocenters and with the dose matrix used as mask to focus the registration on the tumor and surrounding tissue only. Plans ordered by anatomical similarity, are presented to the clinician and are exported to the treatment planning system to be used as a starting point in the treatment planning process.Results: RT‐Analytics is demonstrated on ten clinical cases of breast carcinomas. Using an institutional database of 317 previously treated cases, the search procedure finds anatomical matches at a value of 0.9 or higher as measured by a mutual information metric computed over 30 histogram bins. Without re‐optimizing the treatment plan, dose homogeneity in the breast was within 12%. Minor changes needed to further decrease this inhomogeneity, and the previous optimization constraints and attained DVH can be used as a starting solution in the optimization process. Suggested solutions are also used for quality assurance purposes, to investigate if the attained DVH on new cases meet the quality of previous cases using a population‐based plan assessment Conclusions: RT‐Analytics represents a unique approach to plan generation by using prior planning solutions, and it allows quality control of the plan development process.
SU‐C‐110‐01: Strategies for Online Plan Re‐Optimization: Objective Settings and Starting Stage
Authors: Li T , Zhang Y , Wu Q , Yuan L , Yin F , Wu Q
Published: November 2011

Purpose: To find the most robust strategies of objective setting and starting stage for online plan re‐optimization, so it can be automatically executed within 1 min while providing high quality adaptive plans. Methods: 10 prostate cancer patients, each with 1 planning‐CT and 5 CBCTs, were retrospectively studied to simulate daily re‐optimization. PTV objectives were (same across plans): D95>100% and Dmax<110%. Three OAR optimization objectives were compared: RTOG objectives (same across patients); DVH parameters extracted from original CT‐plans (CT objectives); and DVH parameters extracted from “goal” dose distributions obtained through deformable registration between planning‐CT and CBCT (Deformed‐CT objectives). Two starting stages were compared: optimal‐fluence in original CT‐plan (Warm‐start) and unity‐intensity within PTV (Cold‐start). Conformity index (CI) and homogeneity index (HI) were calculated to assess the target coverage. OAR sparing was evaluated by V50%/V100% for the bladder and V50%/V70Gy for the rectum. Delivery efficiency was evaluated by total‐MU of each plan. Results: (1)Target: CIs (all<1.2) were similar for all objective settings with either Warm‐ or Cold‐start. However, HIs were consistently lower for RTOG (p<0.0001). (2)Rectum: Deformed‐CT objectives achieved slightly lower V70Gy (<2.5cc) than CT or RTOG (p<0.0001). Both CT and Deformed‐CT objectives achieved lower V50% (p<0.0001) than RTOG by 5.7%–23.6%. (3)Bladder: Deformed‐CT and CT objectives had small differences in V100%/V50%, but were better than RTOG (p<0.0001), especially for V50% (6.8%–16.9% reduction). (4)Warm‐start increased total‐MU by 23%±11% for all plans, but also reduced V50% by 9.7%–26.9% for rectum with all objective settings, and reduced V50% by ∼10% for bladder with RTOG setting. (5)Deformed‐CT objectives showed greater advantage over CT objectives when OAR volume in CBCT is >30% larger than planning‐CT. Conclusions: CT and Deformed‐CT objectives are in general superior to RTOG for OAR sparing. Deformed‐CT objective is more robust when OAR volume significantly increases. Warm‐start has better OAR sparing, but significantly increases total‐MU.

Research partially supported by a master research grant from Varian Medical Systems.
SU‐C‐110‐02: Reducing 4D CT Artifacts Using Optimized Sorting Based on Anatomic Similarity
Authors: Maxim P , Johnston E , Murphy J , Diehn M , Loo B
Published: November 2011

Purpose: Four‐dimensional (4D) computed tomography (CT) has been widely used as a tool to characterize respiratory motion in radiotherapy. The two most commonly used 4DCT algorithms sort images by respiratory phase or displacement into a predefined number of bins, and are prone to image artifacts at transitions between bed positions. The purpose of this work is to demonstrate a method of reducing motion artifacts in 4DCT by incorporating anatomic similarity into phase or displacement based sorting protocols. Methods: Ten patient datasets were retrospectively sorted using both displacement and phase based sorting algorithms. Conventional sorting methods allow selection of only the nearest neighbor image in time or displacement within each bin. In our method, for each bed position either the displacement or the phase defines the center of a bin range about which several candidate images are selected. The two dimensional correlation coefficients between slices bordering the interface between adjacent couch positions are then calculated for all candidate pairings. Two slices have a high correlation if they are anatomically similar. Candidates from each bin are then selected to maximize the slice correlation over the entire data set using Dijkstraˈs shortest path algorithm. To assess the reduction of artifacts, two thoracic radiation oncologists independently compared the re‐sorted 4D datasets pair‐wise with conventionally sorted datasets, blinded to the sorting method, to choose which had the least motion artifacts. Agreement between reviewers was evaluated using the weighted kappa score. Results: Anatomically based image selection resulted in 4DCT datasets with significantly reduced motion artifacts with both displacement (P=0.0063) and phase sorting (P=0.00022). The reviewers agreed 34 times and disagreed 6 times. Conclusions: Sorting using anatomic similarity significantly reduces 4DCT motion artifacts compared to conventional phase or displacement based sorting. This improved sorting algorithm is a straightforward extension of the two most common 4DCT sorting algorithms.