bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of durum wheat germplasm adapted to different climatic conditions
Authors: Mondini L. , Farina A. , Porceddu E. , Pagnotta M.A.
Published: December 2009

A study of the extent and patterns of microsatellite diversity in 234 genotypes from Ethiopian durum wheat (Triticum turgidum) landraces was conducted to identify areas of diversity that could be used as a source of new germplasm for developing high yielding and stable varieties. Landraces belonging to nine populations, from three Ethiopian regions [Tigray (T), Gonder (G) and Shewa (S)] with different climates, were analysed by using 28 simple sequence repeat (SSR) markers. The level of polymorphism was high and quite consistent among populations underlining the great diversity existing. The highest level of diversity was found within populations, about 75.9%, while about 5.3% was attributed to differences between regions. The level of expected heterozygosity was on an average, rather high, ranging from 39% to 56%, whereas the observed heterozygosity was, on an average, limited to 14%. An average of about five alleles per locus was detected in each population. Nevertheless, alleles were not equally present in populations as confirmed by the high level of expected heterozygosity. The polymorphism information content (PIC) for the markers assessed showed a wide range of values from 0.14 to 0.92. The likelihood relationships among the nine Ethiopian populations indicated that the material collected in the Gonder region (a wet climate) was genetically more diverse than the materials from Shewa and Tigray (dryer climates). The high number of loci in linkage disequilibrium (LD), up to 23, has demonstrated that the loci were associated irrespective of their physical location. This holds true even if the loci are located on different chromosome arms. Genetic diversity values between populations was very different and was used to produce a dendrogram showing population relationships.
CHANGES IN QUALITY DURING STORAGE OF VACUUM‐PACKED SEA BASS (DICENTRARCHUS LABRAX, Linnaeus, 1758) COOKED BY DIFFERENT METHODS
Authors: TURKKAN AYSE UFUK , CAKLI SUKRAN , KILINC BERNA
Published: December 2009

This work evaluates the chemical, microbiological and sensorial characteristics of vacuum‐packed sea bass processed by different cooking methods under different time/temperature conditions and storage at 2C. The heat treatments applied in core were: 5 min, at 180C for frying, 30 mi, at 230C for baking, and 16 min at 2450 MHz for microwave cooking. Chemical, microbiological and sensory quality changes were investigated periodically. In all groups; the total viable and psycrophilic bacteria counts increased throughout the storage period of vacuum‐packed sea bass. Total viable counts of fried, baked and microwave‐cooked sea bass reached 6.06, 7.00, 7.24 log cfu/g, respectively, after 15 days. On day 15, the total volatile base nitrogen (TVB‐N) value of microwave‐cooked sea bass exceeded the allowable limit of 38.72 mg/100 g, whereas the TVB‐N value of fried and baked sea bass reached 22.46 and 29.85 mg/100 g, respectively. Therefore, it can be concluded that frying at 180C for 5 min in core is the most effective cooking method to ensure the safety and extend the shelf life of fried sea bass, preserving its microbiological guality.

PRACTICAL APPLICATION

This study establishes the chemical, microbiological and sensory quality of vacuum‐packed sea bass and emphasizes the relevance of the quality changes of the different cooked sea bass. Heat treatments and storage temperatures are very important to ensure the safety of the fish product.
RESPONSE SURFACE METHODOLOGY STUDY ON THE POSSIBILITY OF NITRITE REDUCTION BY GLUCONO‐δ‐LACTONE AND ASCORBIC ACID IN TURKISH‐TYPE FERMENTED SAUSAGE (SUCUK)
Authors: YILMAZ MUSTAFA TAHSİN , ZORBA ÖMER
Published: December 2009

The primary goal of this study was to determine the residual nitrite‐reducing effects of glucono‐δ‐lactone (GDL) and ascorbic acid (AA) in Turkish‐type fermented sausage. Response surface methodology was used to investigate the simultaneous effects of processing variables, e.g., nitrite (0–200 mg/kg sausage), GDL (0–0.5% w/w) and AA (0–500 mg/kg sausage) on pH, moisture, residual nitrite, proteolysis, lipolysis, peroxide, yield and sensory score of the sausage. AA significantly (P < 0.01) decreased the residual nitrite level; however, quadratic effect of AA showed an inverse effect. GDL did not produce the same effect on the residual nitrite level. The processing variables had no prominent effect on the proteolysis, lipolysis and peroxide. GDL and AA addition showed a negative effect on the yield and sensory scores of the sausages. The regression model predicted the optimum residual nitrite content to be 0.75 mg/kg. The critical values for nitrite, GDL and AA to obtain this optimum level were 147.56 mg/kg, 0.17% and 565 mg/kg, respectively.

PRACTICAL APPLICATIONS

Residual nitrite level is a major problem in the Turkish‐type fermented sausage product with respect to some health concerns, residual nitrite causes a possible formation of the carcinogenic N‐nitrosamines. The results of this study can be applied to reduce the residual nitrite level in sausage and to find the optimum levels of nitrite, glucono‐δ‐lactone and ascorbic acid levels to maintain the characteristic sausage quality properties. Based on the results, ascorbic acid can be used to reduce the residual nitrite levels in the sausage.
EFFECTS OF DIETARY GLYCINE BETAINE ON BLOOD CHARACTERISTICS AND PORK QUALITY
Authors: HWANG YOUNG HWA , HUR SUN JIN , PARK GU BOO , JOO SEON TEA
Published: December 2009

This study was conducted to determine the effects of dietary glycine betaine on pork quality and blood characteristics. A total of 80 female pigs (Landrace × Yorkshire × Duroc) were randomly allotted into one of four experimental diet groups. Each group of pigs fed with a commercial diet (control) added with 0.2 g glycine betaine (T1), 0.4 g glycine betaine (T2) and 0.6 g glycine betaine (T3)/kg diet during 40 days. Glycine betaine concentrations in plasma and loin muscle were significantly increased by dietary glycine betaine; however, triglyceride concentration in serum was decreased by dietary glycine betaine. Creatine phosphokinase concentrations in plasma had no significant difference among the dietary groups. Redness (a*) was significantly higher in T2 and T3; however, at the first and seventh days of storage, redness (a*) was not significantly different between dietary groups. Shear force was significantly higher in dietary glycine betaine groups at the first day of storage. Cholesterol content was significantly lower in T2 and T3, whereas T1 was not significantly different compared with the control group. In fatty acid composition, the ratio of saturated fatty acids was increased, whereas unsaturated fatty acids were decreased by dietary glycine betaine.

PRACTICAL APPLICATIONS

Glycine betaine is an amino acid (trimethylglycine) present in most organisms, and is an obligatory intermediate in the catabolism of choline. Glycine betaine has been reported to affect some aspects of pork qualities. As a result of this study, dietary glycine betaine should improve meat redness and reduce cholesterol. However, dietary glycine betaine did not influence creatine phosphokinase levels in plasma. These results will be helpful to the pork industry and meat scientists for improving meat qaulity.
MYOFIBRILLAR AND SARCOPLASMIC PROTEIN OXIDATION AND DEGRADATION OF THIN‐LIPPED GRAY MULLET (LIZA RAMADA) DURING REFRIGERATED STORAGE (4C)
Authors: TOKUR BAHAR , POLAT ABDURRAHMAN
Published: December 2009

The oxidation of myofibrillar and sarcoplasmic proteins of thin‐lipped mullet (Liza ramada) in different ages during refrigerated storage (4C), and in vitro oxidation of muscle after 2 and 24 h incubation with Fe+2/H2O2 at 4C were evaluated by means of protein carbonyl content. Changes in myofibrillar and sarcoplasmic proteins were estimated by sodium dodecyl sulfate‐polyacrylamide gel electrophoresis. The carbonyl content of myofibrillar proteins exhibited a regular increase at 2 years of age during the refrigerated storage for 10 days (P < 0.05), and increased at 4 and 6 years of age after 5 days of cold storage (P > 0.05), and then did not significantly change between 5 and 10 days of storage (P > 0.05). Sarcoplasmic proteins showed a decrease in the carbonyl content at 2 years of age during 10 days of storage. However, no significant changes were observed in carbonyl content of sarcoplasmic proteins at 4 and 6 years of age (P > 0.05). An increase in carbonyl content of whole muscle, but not statistically significant, was found at 2, 4 and 6 years of age during 10 days of cold storage. There were no significant differences in oxidation of thin‐lipped gray mullet proteins in all ages between 2 and 24 h of incubation with Fenton‐like oxidation system (Fe+2SO4/H2O2) at 4C (P < 0.05). However, there was a tendency to find an increase in carbonyl content in all ages after 24 h of incubation. Electrophoretic studies in the presence and absence of β‐mercaptoethanol showed that high‐molecular weight polymers via disulfide cross‐linking and/or degradation/digestion by proteolysis could be formed in the myofibrillar proteins in different ages. Slight changes were observed in sarcoplasmic proteins of thin‐lipped gray mullet both in the absence and presence of a disulfide‐splitting agent. These results suggest that there is a probable link between protein oxidation and protelytic degradation of myofibrillar proteins during postmortem storage, and the effects of cold storage on oxidation and possible changes in myofibrillar and sarcoplasmic proteins could be changed depending on ages in same species.

PRACTICAL APPLICATIONS

The degradation of muscle proteins caused by proteolysis is one of the most important quality attributes of fish muscle throughout cold storage. However, knowledge about the effect of oxidative process on proteins and their effect on postmortem quality of fish is less known. In this study, we found a probable link between protein oxidation and degradation of thin‐lipped mullet myofibrillar proteins, and their proteolysis may be stimulated by oxygen radicals during postmortem storage. These determinations are important to prevent protein degradation and improve the shelf life of thin‐lipped mullet during postmortem storage.
ULTIMATE pH EXPLAINS VARIATION IN PORK QUALITY TRAITS
Authors: BOLER D.D. , DILGER A.C. , BIDNER B.S. , CARR S.N. , EGGERT J.M. , DAY J.W. , ELLIS M. , MCKEITH F.K. , KILLEFER J.
Published: December 2009

The objective of this study was to determine the relationship between pH and fresh pork quality. Pigs (n = 988) were harvested at one plant on 6 days over a 2‐month period. Loin pH was recorded at 45 min, and 3 and 24 h postmortem. Loins (n = 840) were classified based on ultimate pH into four categories: low (≤5.44), low/normal (5.45–5.74), high/normal (5.75–6.04) and high (≥6.05). A majority of loins (53.3%) were classified as low/normal, while only 1.3% were classified as low. It was confirmed that 24 h pH was the best predictor of key meat quality traits because 45 min and 3 h pH accounted for less than 5% of the total variation in quality traits. The pH at 24 h postmortem is the best predictor of quality of the three time points tested in this population, because it accounted for over 10% of the variation in several quality attributes.

PRACTICAL APPLICATIONS

Ultimate pH is becoming more widely used in industry applications to segregate carcasses prior to fabrication. The pH has been linked to several important attributes of pork quality, including water‐holding capacity, tenderness and color. While it has been suggested that the pH measured at earlier time points postmortem can be used to predict pork quality, the results of this study suggest that the pH at 24 h postmortem is the best predictor of these characteristics. The addition of 45 min or 3 h pH is of little predictive value for meat quality characteristics in this population. While 24 h pH accounts for some variability in pork quality attributes, more work is still needed to determine factors impacting the quality of pork.
CHANGES IN BIOCHEMICAL AND MICROBIOLOGICAL CHARACTERISTICS OF TURKEY SUCUKS AS AFFECTED BY PROCESSING AND STARTER CULTURE UTILIZATION
Authors: ENSOY ÜMRAN , KOLSARICI NURAY , CANDOĞAN KEZBAN , KARSLIOĞLU BETÜL
Published: December 2009

The effects of starter culture and processing on the microbiological and biochemical characteristics of turkey sucuk were studied during production and storage. No differences (P > 0.05) in proximate composition and salt contents were found in sucuks produced either by traditional or heated methodologies. Both traditional (P < 0.05) and heat‐processed (P > 0.05) sucuks that incorporated S1 had the lowest pH value, and thus the highest titratable acidity. Heating process resulted in about 1 log unit reduction in yeast counts and 1.5 log unit reduction in lactic acid bacteria, total mesophilic aerobic bacteria and micrococci–staphylococci counts of all sucuks. Within the heat‐processed sucuks, heating stage did not result in a significant change in nonprotein nitrogen contents (P > 0.05). Changes in myofibrillar and sarcoplasmic protein were observed because of proteolytic changes during ripening, but, in general, no major difference was observed between sodium dodecyl sulfate‐polyacrylamide gel electrophoresis patterns as a result of starter culture treatments.

PRACTICAL APPLICATIONS

Results of this study can be applied to improve some biochemical and microbiological characteristics of fermented turkey sausages. The findings showed that utilizing commercial starter culture mix, containing Lactobacillus sake, Staphylococcus carnosus and Staphylococcus xylosus II resulted in lower pH value with a higher titratable acidity than traditional style‐fermented turkey sausages. These parameters are responsible for texture development and characteristic taste of fermented sausages.
Citizen oversight of independent police services: Bifurcated accountability, regulation creep, and lesson learning
Authors: Smith Graham
Published: December 2009

By examining developments in England and Wales this article considers police reform in the context of the tension between operational independence and citizen oversight. The article assesses the nexus between regulation and accountability in order to shed light on how a bifurcated accountability paradigm has protected police autonomy. Particular significance is attached to the cold‐blooded police shooting of an innocent man as a critical moment in the recent history of police governance. The lesson‐learning strategy of the Independent Police Complaints Commission, created under the Police Reform Act 2002, is singled out as an important driver of police reform. Although police governance reform in England and Wales is context specific, it is held that appreciation of the regulation accountability nexus and complaints as lesson‐learning opportunities are of significance in other jurisdictions and sectors.
Comparing the legitimacy and effectiveness of global hard and soft law: An analytical framework
Authors: Karlsson‐Vinkhuyzen Sylvia I. , Vihma Antto
Published: December 2009

The international norms that are developed as tools of global governance can be placed on a continuum from traditional “hard law” treaties to the vaguest and voluntary “soft law.” In this article we develop an analytical framework for comparing norms on different positions along the continuum, thus for comparing international hard and soft law. We root the framework in both the rationalist and the constructivist paradigms of international relations by focusing on two overarching evaluative criteria: effectiveness and legitimacy. These broad concepts are divided into smaller building blocks encompassing mechanisms through which norms can exert influence; for example, by changing material incentives, identities, and building capacity, and by contributing to building source‐based, procedural, and substantive legitimacy. We illustrate the applicability of the framework with three norm processes of varying degrees of “softness” in global climate governance.
Regulation and voluntarism: A case study of governance in the making
Authors: Barkay Tamar
Published: December 2009

In this article I analyze a multi‐stakeholder process of environmental regulation. By grounding the article in the literature on regulatory capitalism and governance, I follow the career of a specific legislative process: the enactment of Israel's Deposit Law on Beverage Containers, which aims to delegate the responsibility for recycling to industry. I show that one crucial result of this process was the creation of a non‐profit entity licensed to act as a compliance mechanism. This new entity enabled industry to distance itself from the responsibility of recycling, and thereby frustrated the original objective of the legislation, which was to implement the principle of “extended producer responsibility.” Furthermore, this entity, owned by commercial companies and yet acting as an environmentally friendly organization, allowed industry to promote an anti‐regulatory agenda via a “civic voice.” The study moves methodologically from considering governance as an institutional structure to analyzing the process of “governancing,” through which authoritative capacities and legal responsibilities are distributed among state and non‐state actors. Two key findings are that this process and its outcome (i) are premised on an ideology of civic voluntarism, which ultimately delegates environmental responsibilities to citizens; and (ii) facilitate an anti‐regulatory climate that serves commercial interests.
Testing responsive regulation in regulatory enforcement
Authors: Nielsen Vibeke Lehmann , Parker Christine
Published: December 2009

The policy ideals of responsive regulation have been developed on the basis of substantial empirical evidence. The overall formulation of responsive regulation theory itself, however, has rarely been empirically tested. This article sets out the theoretical concept of responsive regulation in the context of business regulation enforcement and discusses how we might operationalize and empirically measure it. We develop two alternative theoretical interpretations of responsive regulatory enforcement: “tit for tat” responsive regulation and “restorative justice” responsive regulation. We then measure business firms' perceptions of the reactions and counter‐reactions of a regulatory enforcement agency throughout the investigation and enforcement process. We find little evidence of tit for tat responsiveness actually occurring in practice. To the extent that tit for tat responsiveness does exist, we find a small amount of evidence that it has the hypothesized effects on behavior but not on attitudes. We find clearer evidence of restorative justice responsiveness having the hypothesized effects on attitudes but not on behavior.
The regulatory state and the UK Labour Government's re‐regulation of provision in the English National Health Service
Authors: Wright John S. F.
Published: December 2009

Following its election in 1997, the UK Labour Government embarked upon a 10 year program of reform of the National Health Service (NHS). By 2005, Labour had doubled the NHS budget and dramatically transformed the shape of the Service. In England, a basic characteristic of the NHS is the organizational split between provider and commissioning agencies. In this article I argue that Labour's re‐regulation of NHS provision is a coherent representation of the influence of the “regulatory state” in restructuring arrangements between government, market, and society. The article offers an account of the regulatory state based on a discussion of five key theses: The Audit Society, Regulation Inside Government, The New Regulatory State, The British Regulatory State, and Regulatory Capitalism. The article unfolds Labour's program of reform across themes common to these accounts: the division of labor between state and society, the division of labor within the state, the formalization of previously informal controls, and the development of meta‐regulatory techniques of enforced self‐regulation. It concludes that the key themes of the regulatory state are at work in Labour's transformation of NHS provision and it offers a discussion of the implications for both scholars of regulation and the UK and European health policy literature.
Legitimating beliefs: Sources and indicators
Authors: Levi Margaret , Sacks Audrey
Published: December 2009

The more a government is effective and fair, the more legitimacy that government is likely to attain, and the more it will possess the potential to elicit compliance without excessive monitoring or punitive action. We explore this proposition using contemporary survey data from sub‐Saharan Africa. In particular, we are interested in the conditions that promote popular legitimating beliefs that provide support for governments that are attempting to serve their entire populations competently and in a manner that is relatively impartial and equitable. This article provides empirical support for a long hypothesized link between the extent of government effectiveness, procedural justice, and citizens' willingness to defer to governmental tax authority. The sample, drawn from a continuum of developing societies in Africa, allows us to analyze the impact of variations in government effectiveness and citizen perceptions of fairness on the sense of obligation to comply with the tax authorities, our indicator for legitimating beliefs.
Quality of Heart Failure Management: A Comparison of Care Between a Comprehensive Heart Failure Program and a General Cardiology Practice
Authors: Asghar Hannah , Rahko Peter S.
Published: December 2009

This study evaluates adherence to guidelines by heart failure clinicians (HFCs) vs general cardiologists (GCs) for use of implantable cardioverter‐defibrillators (ICDs), biventricular pacing devices (cardiac resynchronization therapy; CRT), and use of medications for heart failure (HF). The authors reviewed 563 patients with HF and an ejection fraction ≤35% for adherence to the 2005 American College of Cardiology/American Heart Association HF guidelines for the use of ICDs, CRT, and medications. There were 324 HFC and 239 GC patients. CRT guidelines were appropriately followed in 86% of HFC and 81% of GC patients ( P=NS). For primary arrhythmia prevention, an ICD was implanted in 107 (42%) HFC and 50 (25%) GC patients ( P<.004). Guidelines were appropriately followed in 77% of HFC and 74% of GC patients ( P=NS). For medications, dose intensity of diuretics, β‐blockers, and angiotensin‐converting enzyme inhibitors was significantly greater in HFC than GC patients. Guideline‐recommended β‐blockers were more frequently utilized by HFCs (97%) than GCs (82%). In conclusion, HFCs and GCs appropriately follow guidelines in the majority of cases, but HFCs use appropriate medications at higher dose intensity.

Congest Heart Fail. 2010;16:65–70. © 2009 Wiley Periodicals, Inc.
The quest for Y‐chromosomal markers – methodological strategies for mammalian non‐model organisms
Authors: GREMINGER MAJA P. , KRÜTZEN MICHAEL , SCHELLING CLAUDE , PIENKOWSKA–SCHELLING ALDONA , WANDELER PETER
Published: December 2009

Tracing maternal and paternal lineages independently to explore breeding systems and dispersal strategies in natural populations has been high on the wish‐list of evolutionary biologists. As males are the heterogametic sex in mammals, such sex‐specific patterns can be indirectly observed when Y chromosome polymorphism is combined with mitochondrial sequence information. Over the past decade, Y‐chromosomal markers applied to human populations have revealed remarkable differences in the demographic history and behaviour between the sexes. However, with a few exceptions, genetic data tracing the paternal line are lacking in most other mammalian species. This deficit can be attributed to the difficulty of developing Y‐specific genetic markers in non‐model organisms and the general low levels of polymorphisms observed on the Y chromosome. Here, we present an overview of the currently employed strategies for developing paternal markers in mammals. Moreover, we review the practical feasibility and requirements of various methodological strategies and highlight their future prospects when combined with new molecular techniques such as next generation sequencing.
Minimally invasive straight laparoscopic total proctocolectomy for ulcerative colitis
Authors: Ozawa H. , Kokuba Y. , Nakamura T. , Naito M. , Sato T. , Hatate K. , Onozato W. , Miura H. , Tsutsui A. , Ikeda A. , Ihara A. , Watanabe M.
Published: December 2009

Introduction: We have performed straight laparoscopic total proctocolectomy for ulcerative colitis, in which all procedures, including transection of the rectum and anastomosis, were performed in the abdominal cavity. The primary objective of this study was to evaluate whether straight laparoscopic total proctocolectomy is technically feasible and safe.

Methods: A retrospective database identified 22 consecutive patients who underwent straight laparoscopic total proctocolectomy for ulcerative colitis between March 1998 and September 2007. Patients were excluded if they required emergency surgery. First, to create a stoma site, a mini‐laparotomy to insert a 15 mm trocar was performed. Seven other trocars, 5 mm in diameter, were then inserted. Mobilization and dissection of the colorectum and anastmosis were performed completely intracorporeally under laparoscopic guidance. Anastomosis of an ileal J‐pouch to the anal canal was performed using the double‐stapling technique.

Results: Nineteen patients were underwent ileal pouch anal canal anastomosis; two underwent ileorectal anastomosis; and one underwent abdominoperineal resection. The median operation time was 355 min (range 255–605); the median blood loss was 50 g (range 0–800); and the median postoperative hospital stay was 24.5 d. Postoperative complications occurred in eight patients, including three (13.6%) with bowel obstruction, two (9.1%) with portal vein thrombosis, one (4.5%) with anastomotic leakage, and one (4.5%) with postoperative hemorrhage. The morbidity rate was 36.4%. There were no intraoperative complications or conversions to conventional surgery.

Conclusion: In the context of this study, we have shown that straight laparoscopic total proctocolectomy is technically feasible and safe in patients with ulcerative colitis.
Laparoscopic sphincter‐preserving surgery for low rectal tumor using prolapsing technique
Authors: Zheng M.H. , Ma J.J. , Zhang T. , Zhu Q.L. , Lu A.G. , Zong Y.P. , Wang M.L. , Li J.W. , Hu W.G. , Mao Z.H. , Dong F. , Zang L.
Published: December 2009

Introduction: With this study, we aimed to assess the feasibility and outcome of laparoscopy‐assisted low anterior resection with a prolapsing technique for low rectal tumors.

Materials and Methods: We studied surgical techniques, recovery status, complications, oncological clearance and the results of short‐term follow‐up in 15 patients who had received laparoscopy‐assisted low anterior resection with a prolapsing technique for low rectal tumors between October 2005 and January 2008.

Results: None of the cases was converted to open surgery. The mean operation time was 185  min (150–232 min), and the mean blood loss was 75 ml (25–105 ml). The mean time for passage of flatus, duration of urinary drainage, and postoperative hospital stay were 3 d (1–4 d), 6 d (5–10 d) and 11 d (7–20 d), respectively. The total amount of lymph nodes harvested was 15 (9–21), and the mean distal margin from the tumor was 2.5 cm (1.0–3.9 cm). No major complications were observed. The mean follow‐up time was 13 months (4–27 months). Neither local recurrence nor metastasis was observed. Acceptable anal function results were obtained in most patients.

Discussion: Laparoscopy‐assisted low anterior resection with a prolapsing technique can be successfully performed.
Improved MAGIC gel for higher sensitivity and elemental tissue equivalent 3D dosimetry
Authors: Zhu Xuping , Reese Timothy G. , Crowley Elizabeth M. , El Fakhri Georges
Published: December 2009

Purpose

Polymer‐based gel dosimeter (MAGIC type) is a preferable phantom material for PET range verification of proton beam therapy. However, improvement in elemental tissue equivalency (specifically O/C ratio) is very desirable to ensure realistic time‐activity measurements.

Methods

Glucose and urea was added to the original MAGIC formulation to adjust the O/C ratio. The dose responses of the new formulations were tested with MRI transverse relaxation rate (R2) measurements.

Results

The new ingredients improved not only the elemental composition but also the sensitivity of the MAGIC gel. The O/C ratios of our new gels agree with that of soft tissue within 1%. The slopes of dose response curves were 1.6–2.7 times larger with glucose. The melting point also increased by . Further addition of urea resulted in a similar slope but with an increased intercept and a decreased melting point.

Conclusions

Our improved MAGIC gel formulations have higher sensitivity and better elemental tissue equivalency for 3D dosimetry applications involving nuclear reactions.
Evaluation of the interplay effect when using RapidArc to treat targets moving in the craniocaudal or right‐left direction
Authors: Court Laurence , Wagar Matthew , Berbeco Ross , Reisner Adam , Winey Brian , Schofield Debbie , Ionascu Dan , Allen Aaron M. , Popple Richard , Lingos Tania
Published: December 2009

Purpose

We have investigated the dosimetric errors caused by the interplay between the motions of the LINAC and the tumor during the delivery of a volume modulated arc therapy treatment. This includes the development of an IMRT QA technique, applied here to evaluate RapidArc plans of varying complexity.

Methods

An IMRT QA technique was developed, which involves taking a movie of the delivered dose (0.2 s frames) using a 2D ion chamber array. Each frame of the movie is then moved according to a respiratory trace and the cumulative dose calculated. The advantage of this approach is that the impact of turning the beam on at different points in the respiratory trace, and of different types of motion, can be evaluated using data from a single irradiation. We evaluated this technique by comparing with the results when we actually moved the phantom during irradiation. RapidArc plans were created to treat a 62 cc spherical tumor in a lung phantom (16 plans) and a 454 cc irregular tumor in an actual patient (five plans). The complexity of each field was controlled by adjusting the MU (312–966 MU). Each plan was delivered to a phantom, and a movie of the delivered dose taken using a 2D ion chamber array. Patient motion was modeled by shifting each dose frame according to a respiratory trace, starting the motion at different phases. The expected dose distribution was calculated by blurring the static dose distribution with the target motion. The dose error due to the interplay effect was then calculated by comparing the delivered dose with the expected dose distribution. Peak‐to‐peak motion of 0.5, 1.0, and 2.0 cm in the craniocaudal and right‐left directions, with target periods of 3 and 5 s, were evaluated for each plan (252 different target motion/plan combinations).

Results

The daily dose error due to the interplay effect was less than 10% for 98.4% of all pixels in the target for all plans investigated. The percentage of pixels for which the daily dose error could be larger than 5% increased with increasing plan complexity (field MU), but was less than 15% for all plans if the motion was 1 cm or less. For 2 cm motion, the dose error could be larger than 5% for 40% of pixels, but was less than 5% for more than 80% of pixels for , and was less than 10% for 99% of all pixels. The interplay effect was smaller for 3 s periods than for 5 s periods.

Conclusions

The interplay between the motions of the LINAC and the target can result in an error in the delivered dose. This effect increases with plan complexity, and with target magnitude and period. It may average out after many fractions.
CT colonography: Advanced computer‐aided detection scheme utilizing MTANNs for detection of “missed” polyps in a multicenter clinical trial
Authors: Suzuki Kenji , Rockey Don C. , Dachman Abraham H.
Published: December 2009

Purpose

The purpose of this study was to develop an advanced computer‐aided detection (CAD) scheme utilizing massive‐training artificial neural networks (MTANNs) to allow detection of “difficult” polyps in CT colonography (CTC) and to evaluate its performance on false‐negative (FN) CTC cases that radiologists “missed” in a multicenter clinical trial.

Methods

The authors developed an advanced CAD scheme consisting of an initial polyp‐detection scheme for identification of polyp candidates and a mixture of expert MTANNs for substantial reduction in false positives (FPs) while maintaining sensitivity. The initial polyp‐detection scheme consisted of (1) colon segmentation based on anatomy‐based extraction and colon‐based analysis and (2) detection of polyp candidates based on a morphologic analysis on the segmented colon. The mixture of expert MTANNs consisted of (1) supervised enhancement of polyps and suppression of various types of nonpolyps, (2) a scoring scheme for converting output voxels into a score for each polyp candidate, and (3) combining scores from multiple MTANNs by the use of a mixing artificial neural network. For testing the advanced CAD scheme, they created a database containing 24 FN cases with 23 polyps (range of ; average of ) and a mass , which were “missed” by radiologists in CTC in the original trial in which 15 institutions participated.

Results

The initial polyp‐detection scheme detected 63% of the missed polyps with 21.0 FPs per patient. The MTANNs removed 76% of the FPs with loss of one true positive; thus, the performance of the advanced CAD scheme was improved to a sensitivity of 58% with 8.6 FPs per patient, whereas a conventional CAD scheme yielded a sensitivity of 25% at the same FP rate (the difference was statistically significant).

Conclusions

With the advanced MTANN CAD scheme, 58% of the polyps missed by radiologists in the original trial were detected and with a reasonable number of FPs. The results suggest that the use of an advanced MTANN CAD scheme may potentially enhance the detection of “difficult” polyps.
Automatic selection of tube potential for radiation dose reduction in CT: A general strategy
Authors: Yu Lifeng , Li Hua , Fletcher Joel G. , McCollough Cynthia H.
Published: December 2009

Purpose

To optimize radiation dose efficiency in CT while maintaining image quality, it is important to select the optimal tube potential. The selection of optimal tube potential, however, is highly dependent on patient size and diagnostic task. The purpose of this work was to develop a general strategy that allows for automatic tube potential selection for each individual patient and each diagnostic task.

Methods

The authors propose a general strategy that allows automatic adaptation of the tube potential as a function of patient size and diagnostic task, using a novel index of image quality, “iodine contrast to noise ratio with a noise constraint (iCNR_NC),” to characterize the different image quality requirements by various clinical applications. The relative dose factor (RDF) at each tube potential to achieve a target image quality was then determined as a function of patient size and the noise constraint parameter. A workflow was developed to automatically identify the optimal tube potential that is both dose efficient and practically feasible, incorporating patient size and diagnostic task. An experimental study using a series of semianthropomorphic thoracic phantoms was used to demonstrate how the proposed general strategy can be implemented and how the radiation dose reduction achievable by the tube potential selection depends on phantom sizes and noise constraint parameters.

Results

The proposed strategy provides a flexible and quantitative way to select the optimal tube potential based on the patient size and diagnostic task. The noise constraint parameter can be adapted for different clinical applications. For example, for noncontrast routine exams; for contrast‐enhanced routine exams; and for CT angiography. For the five thoracic phantoms in the experiment, when , the optimal tube potentials were 80, 100, 100, 120, 120, respectively. The corresponding RDFs (relative to 120 kV) were 78.0%, 90.9%, 95.2%, 100%, and 100%. When , the optimal tube potentials were 80, 80, 80, 100, 100, respectively, with corresponding RDFs of 34.7%, 44.7%, 54.7%, 60.8%, and 89.5%.

Conclusions

A general strategy to automatically select the most dose efficient tube potential for CT exams was developed that takes into account patient size and diagnostic task. Dependent on the patient size and the selection of noise constraint parameter for different diagnostic tasks, the dose reduction at each tube potential, quantified explicitly with the RDF, varies significantly.
Calibration of a novel four‐dimensional diode array
Authors: Yan Guanghua , Lu Bo , Kozelka Jakub , Liu Chihray , Li Jonathan G.
Published: December 2009

Purpose

The aim of this work is to develop effective calibration methods for a novel four‐dimensional (4D) diode array for pretreatment verification of intensity‐modulated radiation therapy (IMRT) and rotational therapy.

Methods

A novel 4D diode array (ArcCHECK, Sun Nuclear, Melbourne, FL) was developed to meet the needs of appropriate and efficient quality assurance for IMRT and especially rotational radiotherapy. The diode array presents a consistent detector image in beam's eye view at arbitrary gantry angles due to isotropic arrangement of diodes in a three‐dimensional (3D) cylindrical phantom. The simultaneous update of all diodes on the detector array (fourth dimension) makes it capable of time‐resolved beam delivery analysis with any rotational delivery techniques. The calibration procedure consisted of delivering and measuring a series of calibration beams with 5.8° angular spacing surrounding the cylindrical diode array. Correction factors for diode intrinsic sensitivity and directional response dependence were derived from these measurements. A real‐time algorithm to derive gantry angles based on the detector signal was developed to interpolate and apply the corresponding angular correction factors.

Results

The calibration was validated with ion chamber scanned beam profiles in a 3D water tank. Excellent agreement was observed between diode array measurement and treatment planning system calculation. The accuracy of the gantry angle derivation algorithm was within 1° which caused a less than 0.2% dosimetric uncertainty.

Conclusions

With the proposed calibration method and the automatic gantry angle derivation algorithm, the 4D diode array achieved isotropic detector response and is suitable for both IMRT and rotational therapy pretreatment verification.
Exploring nonlinear feature space dimension reduction and data representation in breast CADx with Laplacian eigenmaps and ‐SNE
Authors: Jamieson Andrew R. , Giger Maryellen L. , Drukker Karen , Li Hui , Yuan Yading , Bhooshan Neha
Published: December 2009

Purpose

In this preliminary study, recently developed unsupervised nonlinear dimension reduction (DR) and data representation techniques were applied to computer‐extracted breast lesion feature spaces across three separate imaging modalities: Ultrasound (U.S.) with 1126 cases, dynamic contrast enhanced magnetic resonance imaging with 356 cases, and full‐field digital mammography with 245 cases. Two methods for nonlinear DR were explored: Laplacian eigenmaps [M. Belkin and P. Niyogi, “Laplacian eigenmaps for dimensionality reduction and data representation,” Neural Comput. 15, 1373–1396 (2003)] and ‐distributed stochastic neighbor embedding (‐SNE) [L. van der Maaten and G. Hinton, “Visualizing data using t‐SNE,” J. Mach. Learn. Res. 9, 2579–2605 (2008)].

Methods

These methods attempt to map originally high dimensional feature spaces to more human interpretable lower dimensional spaces while preserving both local and global information. The properties of these methods as applied to breast computer‐aided diagnosis (CADx) were evaluated in the context of malignancy classification performance as well as in the visual inspection of the sparseness within the two‐dimensional and three‐dimensional mappings. Classification performance was estimated by using the reduced dimension mapped feature output as input into both linear and nonlinear classifiers: Markov chain Monte Carlo based Bayesian artificial neural network (MCMC‐BANN) and linear discriminant analysis. The new techniques were compared to previously developed breast CADx methodologies, including automatic relevance determination and linear stepwise (LSW) feature selection, as well as a linear DR method based on principal component analysis. Using ROC analysis and validation, 95% empirical confidence intervals were computed for the each classifier's AUC performance.

Results

In the large U.S. data set, sample high performance results include, with 95% empirical bootstrap interval [0.787;0.895] for 13 ARD selected features and with interval [0.817;0.906] for four LSW selected features compared to 4D t‐SNE mapping (from the original 81D feature space) giving with interval [0.847;0.919], all using the MCMC‐BANN.

Conclusions

Preliminary results appear to indicate capability for the new methods to match or exceed classification performance of current advanced breast lesion CADx algorithms. While not appropriate as a complete replacement of feature selection in CADx problems, DR techniques offer a complementary approach, which can aid elucidation of additional properties associated with the data. Specifically, the new techniques were shown to possess the added benefit of delivering sparse lower dimensional representations for visual interpretation, revealing intricate data structure of the feature space.
Technical Note: Deformable image registration on partially matched images for radiotherapy applications
Authors: Yang Deshan , Goddu S. Murty , Lu Wei , Pechenaya Olga L. , Wu Yu , Deasy Joseph O. , El Naqa Issam , Low Daniel A.
Published: December 2009

In radiation therapy applications, deformable image registrations (DIRs) are often carried out between two images that only partially match. Image mismatching could present as superior‐inferior coverage differences, field‐of‐view (FOV) cutoffs, or motion crossing the image boundaries. In this study, the authors propose a method to improve the existing DIR algorithms so that DIR can be carried out in such situations. The basic idea is to extend the image volumes and define the extension voxels (outside the FOV or outside the original image volume) as NaN (not‐a‐number) values that are transparent to all floating‐point computations in the DIR algorithms. Registrations are then carried out with one additional rule that NaN voxels can match any voxels. In this way, the matched sections of the images are registered properly, and the mismatched sections of the images are registered to NaN voxels. This method makes it possible to perform DIR on partially matched images that otherwise are difficult to register. It may also improve DIR accuracy, especially near or in the mismatched image regions.
Dose perturbations by two carbon fiber treatment couches and the ability of a commercial treatment planning system to predict these effects
Authors: Gerig L. H. , Niedbala M. , Nyiri B. J.
Published: December 2009

Purpose

To measure the effect of the treatment couch on dose distributions and to investigate the ability of a modern planning system to accurately model these effects.

Methods

This work measured the dose perturbation at depth and in the dose buildup region when one of two treatment couches, CIVCO (formerly MED‐TEC) or Medical Intelligence, was placed between a photon beam source (6, 10, and 18 MV) and the phantom. Beam attenuation was measured in the center of a cylindrical acrylic phantom with a Farmer type ion chamber at multiple gantry angles. Dose buildup was measured in Solid Water with plane parallel ion chambers (NACP‐02 and PTW Markus) with the beam normal to both the phantom and couch surfaces. The effective point of measurement method as described [M. R. McEwen et al. “The effective point of measurement of ionization chambers and the build‐up anomaly in MV x‐ray beams,” Med. Phys. 35(3), 950–958 (2008)] was employed to calculate dose in the buildup region. Both experiments were modeled in XiO. Images of the treatment couches were merged with images of the phantoms such that they were included as part of the “patient” image. Dose distributions calculated with superposition and fast superposition algorithms were compared to measurement.

Results

The two treatment couches have different radiological signatures and dissimilar water equivalent thicknesses (4.2 vs 6.3 mm.) Maximum attenuation was 7%. Both couches caused significant loss of skin sparing, the worst case showing an increase in surface dose from 17% (no couch) to 88% (with couch). The TPS accurately predicted the surface dose (±3%) and the attenuation at depth when the phantom was in contact with the couch. For the open beam the TPS was less successful in the buildup region.

Conclusions

The treatment couch is not radio‐transparent. Its presence between the patient and beam source significantly alters dose in the patient. For the most part, a modern treatment planning system can adequately predict the altered dose distribution.