bluuebunny/crossref_metadata_2025 huggingface dataset:
Proliferative responses in the local lymph node assay associated with concomitant exposure to 1,4‐phenylenediamine and methyldibromo glutaronitrile: evidence for synergy?
Authors: Jowsey Ian R. , Basketter David A. , Irwin Anita
Published: July 2008

Background:  A key consideration when undertaking risk assessments should be the potential for synergy between contact allergens. Previously, this concept has only been investigated during elicitation in contact allergic individuals.

Objective:  To determine whether there exists evidence for synergy between contact allergens during the induction phase of skin sensitization using the mouse local lymph node assay (LLNA) as a model system.

Method:  Proliferative responses in draining lymph nodes were assessed with increasing concentrations of 1,4‐phenylenediamine (PPD), methyldibromo glutaronitrile (MDBGN), and a combination of PPD and MDBGN.

Result:  Data from each of two independent experiments show that lymph node cell proliferation associated with combined exposure to PPD and MDBGN was, in general, only modestly increased relative to that predicted from a simple summation of their individual responses.

Conclusions:  Although the increase in response is very modest, it does imply a relationship between this combination of sensitizers that may not be simply additive in terms of their ability to stimulate proliferative responses in draining lymph nodes. The reproducibility of this observation should be confirmed in future studies with additional pairs of contact allergens to ascertain whether or not this represents evidence of synergy.
Contact sensitization to 4,4′‐diaminodiphenylmethane and to isocyanates among general dermatology patients
Authors: Liippo Jussi , Lammintausta Kaija
Published: July 2008

Background:  Diisocyanates and 4,4′‐diaminodiphenylmethane (MDA) are industrial sensitizers. Occupational asthma is a risk among workers exposed to diisocyanates. Exposure may also lead to contact sensitization and allergic contact dermatitis.

Objective:  The aim of this study was to determine the occurrence of contact sensitization to MDA and to diisocyanates among general dermatology patients.

Patients and methods:  Patch testing with MDA was carried out in 1595 patients. Diphenylmethane‐4,4′‐diisocyanate (MDI) and toluene‐2,4‐diisocyanate (TDI) were tested in 1023 patients and isophorone diisocyanate (IPDI) and 1,6‐hexamethylene diisocyanate (HDI) in 433 patients. The clinical data and sources of exposure are analysed.

Results:  MDA reactions were seen in 17 (1.1%) patients and MDI reactions in 4 patients. Six MDA‐positive patients reacted to p‐phenylenediamine and two to epoxy chemicals. 5/10 of the TDI reactions were seen concurrently with reactions to MDI, MDA, HDI, or to IPDI. IPDI reactions were seen in eight patients and HDI reactions in two patients. Possible sources of exposure were traced in most patients, although the association with the current dermatitis was not apparent in all cases.

Conclusion:  (Di)isocyanates may induce contact sensitization with or without allergic contact dermatitis.
Associations between baseline allergens and polysensitization
Authors: Carlsen Berit Christina , Menné Torkil , Johansen Jeanne Duus
Published: July 2008

Background:  Identification of patients at risk of developing polysensitization is not possible at present. An association between weak sensitizers and polysensitization has been hypothesized.

Objectives:  To examine associations of 21 allergens in the European baseline series to polysensitization.

Patients/Methods:  From a database‐based study with 14 998 patients patch tested with the European baseline series between 1985 and 2005, a group of 759 (5.1%) patients were polysensitized. Odds ratios were calculated to determine the relative contribution of each allergen to polysensitization.

Results:  Seven allergens – parabens mix, N‐isopropyl‐N‐phenyl‐p‐phenylenediamine, sesquiterpene lactone mix, wool alcohols, potassium dichromate, Myroxylon pereirae, and cobalt chloride – showed statistically significant positive associations to polysensitization. Five allergens p‐phenylenediamine, neomycin sulfate, epoxy resin, primin, and nickel sulfate showed statistically significant negative associations to polysensitization. For the allergens with the strongest associations, only every second individual with these particular allergies had two or more additional allergies.

Conclusions:  No common denominator for the association between the allergens and the polysensitization was apparent, and any association, whether positive or negative, was relatively low. Based on these results, sensitization to specific baseline allergens cannot be used as risk indicators for polysensitization.
BODIPY‐Cholesterol: A New Tool to Visualize Sterol Trafficking in Living Cells and Organisms
Authors: Hölttä‐Vuori Maarit , Uronen Riikka‐Liisa , Repakova Jarmila , Salonen Emppu , Vattulainen Ilpo , Panula Pertti , Li Zaiguo , Bittman Robert , Ikonen Elina
Published: July 2008

Analysis of sterol distribution and transport in living cells has been hampered by the lack of bright, photostable fluorescent sterol derivatives that closely resemble cholesterol. In this study, we employed atomistic simulations and experiments to characterize a cholesterol compound with fluorescent boron dipyrromethene difluoride linked to sterol carbon‐24 (BODIPY‐cholesterol). This probe packed in the membrane and behaved similarly to cholesterol both in normal and in cholesterol‐storage disease cells and with trace amounts allowed the visualization of sterol movement in living systems. Upon injection into the yolk sac, BODIPY‐cholesterol did not disturb zebrafish development and was targeted to sterol‐enriched brain regions in live fish. We conclude that this new probe closely mimics the membrane partitioning and trafficking of cholesterol and, because of its excellent fluorescent properties, enables the direct monitoring of sterol movement by time‐lapse imaging using trace amounts of the probe. This is, to our knowledge, the first cholesterol probe that fulfills these prerequisites.
Current controversies in perinatal steroid therapy
Authors: Eventov‐Friedman S , Shinwell ES
Published: July 2008

Few therapies in perinatal medicine have created as much controversy as corticosteroids. Despite five decades of extensive research and practice, major areas of uncertainty remain. In this article, we review the most current evidence on both antenatal and postnatal therapy.

Conclusion: Overall, it is clear that we must continue to investigate the most appropriate doses of the ideal preparation in the most appropriate target populations before we can let the steroid issues rest.
Quality of care of VLBW neonates: relationship between unit volume and outcome is different between metropolitan and rural regions
Authors: Jochum F , Schmidt B , Schunk K , Hesse V , Distler B , Laske G , V.Moers A , Dombrowsky M , Elling D , Kentenich H , Mendling W , Untch M , Grüning T , Abou‐Dakn M
Published: July 2008

Background: Recent studies from predominantly rural areas in Germany show that neonatal outcome of very low birth weight (VLBW) neonates is (on average) inferior with lower NICU (neonatal intensive care unit) volume. However, there are no data available which show that study results of one specific region can be transferred to other areas with possibly different medical infrastructure and needs.

Aim: It was investigated whether a systematic difference of treatment quality between smaller (1000–2000 births/year; ≤20 neonatal beds) vs. larger neonatal centres in Berlin (>3000 births/year; >20 neonatal beds) exists. Furthermore, the results are compared to data from a rural region in order to discuss transferability between regions.

Methods: Retrospectively, completely, and for the first time, the data of all centres which treat VLBW neonates (≤1500 g birth weight) in the city‐state of Berlin, Germany, from the years 2003/2004 were reviewed.

Results: Our study showed no difference in the treatment quality of smaller vs. larger neonatal units in Berlin. This result differs from those of a study in Baden‐Württemberg, a predominately rural state, with different medical infrastructure than Berlin.

Conclusion: The present study suggests that regional investigations on the infrastructure vs. treatment outcome are not transferable between areas. Patient volume/unit appears inadequate for predicting the future treatment quality of neonatal departments. Direct quality indicators are stable for the assessed departments and should be preferably used to organize medical infrastructure.
High maternal body mass index increases the risk of neonatal early onset group B streptococcal disease
Authors: Håkansson Stellan , Källen Karin
Published: July 2008

Objective: The aim of this study was to analyse the occurrence of neonatal early onset group B streptococcal (EOGBS) disease relative to maternal body mass index (BMI).

Method: A cohort of Swedish parturients with an early pregnancy BMI registered was investigated. Data were retrieved from population‐based registers during 1997–2001, (n = 344 127, elective caesarean section excluded). Medical records of all infants with a diagnosis of EOGBS septicaemia (P36.0) were scrutinized for verification of the diagnosis. There were 136 cases with blood culture‐positive septicaemia and 112 cases with clinical infection. Odds ratios (OR) and 95% confidence intervals (CI) were calculated using multiple logistic regression.

Results: In obese parturients with BMI > 30, there was an 80% increased risk for verified neonatal EOGBS disease (OR 1.8, 95% CI 1.1–3.0). When cases with clinical sepsis were included a significant risk increment was also found in overweight women with BMI 25.0–29.9 (OR 1.5, 95% CI 1.1–2.0).

Conclusion: Maternal obesity and overweight are risk factors associated with increased risk of neonatal EOGBS disease.
Sudden oronasal bleeding in a young child
Authors: Hey Edmund
Published: July 2008

Sudden severe upper‐airway obstruction occurring in a hospital setting can sometimes precipitate an episode of acute haemorrhagic pulmonary oedema. A review of 197 published case reports shows that the presenting feature is almost always the sudden appearance of blood stained fluid coming up through the larynx or out through the mouth and nose of an adult or child in obvious respiratory distress. Such overt features are seen in 10–15% of cases of sudden severe, but sub‐lethal, upper‐airway obstruction. Signs normally appear within minutes once the obstruction is relieved but are occasionally only recognized after 1–4 h. All signs and symptoms usually resolve within 12–24 h. Other causes of acute pulmonary haemorrhage are rare in young children.

Conclusion: If what looks like blood is seen in, or coming from, the mouth or nose of a previously healthy young child who has suddenly become distressed and started to struggle for breath, that child has most probably suffered an episode of acute pulmonary oedema, and the commonest precipitating cause is sudden upper‐airway obstruction.
Protective Effect of Extract from Paeonia lactiflora and Astragalus membranaceus against Liver Injury Induced by Bacillus Calmette‐Guérin and Lipopolysaccharide in Mice
Authors: Sun Wu‐Yi , Wei Wei , Gui Shuang‐Ying , Wu Li , Wang Hua
Published: July 2008

Abstract:  Paeonia lactiflora and Astragalus membranaceus are two popular traditional Chinese medicines, commonly used in Chinese herb prescription to treat liver disease. The extract from the roots of P. lactiflora and A. membranaceus demonstrated better hepatoprotective activity than the herbs used individually as shown in our previous studies. The present study was carried out to investigate the effects of P. lactiflora and A. membranaceus extract on immunological liver injury in mice induced by Bacillus Calmette‐Guérin and lipopolysaccharide (BCG/LPS) and to explore a possible mechanism. After administration of P. lactiflora and A. membranaceus (60, 120 and 240 mg/kg, intragastrically) daily for 10 days, the extract significantly reduced the degree of liver damage in BCG/LPS‐induced liver injury, as well as the elevation of serum transaminase activities and level of nitric oxide in live injury mice. The extract also restored the decrease in superoxide dismutase and glutathione peroxidase activities and inhibited the formation of lipid peroxidative products. Moreover, P. lactiflora and A. membranaceus (60, 120 and 240 mg/kg, intragastrically) repressed high levels of tumour necrosis factor‐α (TNF‐α) and interleukin‐1 (IL‐1) from peritoneal macrophages. In the primary cultured Kupffer cells, P. lactiflora and A. membranaceus also significantly decreased the production of TNF‐α and IL‐1 in cells stimulated with LPS (5 µg/ml). These results suggest that P. lactiflora and A. membranaceus have a protective effect on BCG/LPS‐induced liver injury mice, which might be associated with the antioxidant properties, ability to reduce nitric oxide production and suppression of Kupffer cell activity and pro‐inflammatory mediator and cytokines production.
In vitroInhibition of CYP1A2 by Model Inhibitors, Anti‐Inflammatory Analgesics and Female Sex Steroids: Predictability ofin vivoInteractions
Authors: Karjalainen Marjo J. , Neuvonen Pertti J. , Backman Janne T.
Published: July 2008

Abstract: The cytochrome P450 enzyme CYP1A2 is crucial for the metabolism of many drugs, for example, tizanidine. As the effects of several non‐steroidal anti‐inflammatory drugs (NSAID) and female sex steroids on CYP1A2 activityin vitroare unknown, their effects on phenacetin O‐deethylation were studied and compared with the effects of model inhibitors in human liver microsomes, followed by prediction of their interaction potential with tizanidinein vivo.In vitro, fluvoxamine, tolfenamic acid, mefenamic acid and rofecoxib potently inhibited CYP1A2 [the 50% inhibitory concentration (IC50) < 10 µM]. Ethinyloestradiol, celecoxib, desogestrel and zolmitriptan were moderate (IC5020–200 µM), and etodolac, ciprofloxacin, etoricoxib and gestodene weak inhibitors of CYP1A2 (IC50 > 200 µM). At 100 µM, the other tested NSAIDs and steroids inhibited CYP1A2 less than 35%. Pre‐incubation increased the inhibitory effects of rofecoxib, progesterone and desogestrel. Using the free portal plasma inhibitor concentration and the competitive inhibition model, the effect of fluvoxamine and the lack of effects of tolfenamic acid and celecoxib on tizanidine pharmacokinetics in human beings were well predicted. However, the effects of ciprofloxacin, rofecoxib and oral contraceptives were greatly underestimated even when the predictions were based on their total portal plasma concentration. Besides rofecoxib, and possibly mefenamic acid, other NSAIDs were predicted not to significantly inhibit CYP1A2 in human beings. The type of enzyme inhibition, particularly metabolism‐dependent inhibition, free inhibitor concentration and accumulation of the inhibitor into the hepatocytes should be considered in extrapolations ofin vitroresults to human beings.
Cytoprotective Effect of Mangiferin on Benzo(a)pyrene‐Induced Lung Carcinogenesis in Swiss Albino Mice
Authors: Rajendran Peramaiyan , Ekambaram Ganapathy , Sakthisekaran Dhanapal
Published: July 2008

Abstract:  Antioxidants are one of the key players in tumourigenesis, and several natural and synthetic antioxidants have been shown to have anticancer effects. In the present investigation, the efficacy of mangiferin on the antioxidant status of benzo(a)pyrene‐induced lung carcinogenesis in Swiss albino mice was assessed. The animals were divided into five groups. The animals in groups I and V were normal control and mangiferin control, respectively. Groups II, III and IV were administered with benzo(a)pyrene (50 mg/kg body weight, orally) for 4 weeks (twice a week) to induced lung carcinogenesis. Starting 1 week prior to benzo(a)pyrene administration, group III animals were treated with mangiferin (100 mg/kg body weight) in the diet for 18 weeks; 12 weeks after benzo(a)pyrene administration, group III animals were treated with mangiferin that continued until the end of the experiment period (18 weeks). At the end of the experiment period, the reactive oxygen species, glutathione and the activities of antioxidant enzymes were assessed in both lung and liver tissues. The levels of glutathione, superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, vitamin E and vitamin C were decreased in group II animals. However, in the mangiferin + benzo(a)pyrene‐treated groups III and IV, the levels of GSH and the activities of antioxidant enzymes in both lung and liver were improved when compared with benzo(a)pyrene‐induced group II animals. In addition, the finding that mangiferin decreased reactive oxygen species levels and enhanced antioxidant status suggests that this polyphenol might also be of value in the prevention of benzo(a)pyrene‐induced lung carcinogenesis.
Effects of Short‐Term Exposure to Manganese on the Adult Rat Brain Antioxidant Status and the Activities of Acetylcholinesterase, (Na+,K+)‐ATPase and Mg2+‐ATPase: Modulation by l‐Cysteine
Authors: Liapi Charis , Zarros Apostolos , Galanopoulou Panagiota , Theocharis Stamatios , Skandali Nikolina , Al‐Humadi Hussam , Anifantaki Foteini , Gkrouzman Elena , Mellios Zois , Tsakiris Stylianos
Published: July 2008

Abstract:  Manganese (Mn) is an essential metalloenzyme component that in high doses can exert serious oxidative and neurotoxic effects. The aim of this study was to investigate the potential effect of the antioxidant l‐cysteine (Cys, 7 mg/kg) on the adult rat brain total antioxidant status (TAS) and the activities of acetylcholinesterase (AChE), Na+,K+‐ATPase and Mg2+‐ATPase induced by short‐term Mn administration (as Mn chloride, 50 mg/kg). Twenty‐eight male Wistar rats were divided into four groups: A (saline‐treated control), B (Mn), C (Cys) and D (Mn and Cys). All rats were treated once daily, for 1 week with intraperitoneal injections of the tested compounds. Rats were killed by decapitation and mentioned parameters were measured spectrophotometrically. Rats treated with Mn exhibited a significant reduction in brain TAS (−39%, P < 0.001, B versus A) that was partially reversed by Cys co‐administration (−13%, P < 0.01, D versus A), while Cys (group C) had no effect on TAS. The rat brain AChE activity was found significantly increased by both Mn (+21%, P < 0.001, B versus A) and Cys (+61%, P < 0.001, C versus A), while it was adjusted into the control levels by the co‐administration of Mn and Cys. The activity of rat brain Na+,K+‐ATPase was not affected by Mn administration, while Mg2+‐ATPase exhibited a slight but statistically significant reduction in its activity (−9%, P < 0.01, B versus A) due to Mn, which was further reduced by Cys co‐administration. The above findings suggest that short‐term Mn in vivo administration causes a statistically significant decrease in the rat brain TAS and an increase in AChE activity. Both effects can be, partially or totally, reversed into the control levels by Cys co‐administration (which could thus be considered for future applications as a neuroprotective agent against chronic exposure to Mn and the treatment of manganism). The activity of Na+,K+‐ATPase is not affected by Mn, while Mg2+‐ATPase activity is slightly (but significantly) inhibited by Mn, possibly due to Mg replacement.
Disposition of a CYP2C9 Phenotyping Agent, Losartan, Is Not Influenced by the Common 3435C > T Variation of the Drug Transporter Gene ABCB1 (MDR1)
Authors: Yasar Umit , Babaoglu Melih O. , Bozkurt Atila
Published: July 2008

Abstract:  Losartan is oxidized to E3174 by cytochrome P450 2C9 (CYP2C9); it has been suggested as a useful probe drug for CYP2C9 activity. It has also been shown to be a substrate for the drug‐efflux transporter ATP‐binding cassette sub‐family B member 1 (ABCB1, MDR1). Both CYP2C9 and ABCB1 genes are polymorphic. The aim of the study was to determine if losartan disposition was influenced by the 3435C > T polymorphism of ABCB1 in healthy persons. These participants (n = 58) whose CYP2C9 genotypes and phenotypes were determined previously were genotyped for 3435C > T polymorphism in ABCB1. The concentrations of losartan and E3174 were compared across genotypes for ABCB1 3435C > T variation. For persons with the ABCB1 3435 CC, CT, TT genotypes, the concentrations (µM, means ± S.D.) of neither losartan (1.76 ± 0.87, 1.68 ± 0.84 and 1.80 ± 0.85, respectively, P = 0.70) nor E3174 (2.97 ± 2.49, 2.53 ± 2.09 and 3.18 ± 2.75, respectively, P = 0.65) were significantly different. These results suggest that ABCB1 3435C > T polymorphism does not have any influence on losartan disposition. Therefore, ABCB1 3435C > T polymorphism is probably not a confounding factor in the prediction of CYP2C9 activity by using losartan as a probe agent.
CONTAMINATION OF PATULIN IN CLEAR APPLE JUICE IN MASHHAD, IRAN
Authors: KARIMI GHOLAMREZA , HASSANZADEH MOHAMMAD , YAZDANPANAH HASSAN , NAZARI FIRUZEH , IRANSHAHI MEHRDAD , NILI AMIR
Published: July 2008

Patulin is a frequent contaminant of moldy and rotten apples and apple products. The aim of this study was to evaluate patulin contamination in 58 apple juices collected from a retail market in Mashhad during winter and spring of 2006.

Samples were assayed for patulin by high‐performance liquid chromatography. Fifty‐four samples were positive for patulin at levels that ranged from 10.5 to 121.8 µg/L, and six samples had patulin levels higher than 50 µg/L. The overall mean of patulin concentration was 29.2 ± 19.5 µg/L. Forty‐eight samples had patulin concentration between 5 and 50 µg/L. Although the mean concentration of patulin samples was lower than Iranian maximum tolerated level of 50 µg/L, contamination of 10% of the samples at levels higher than 50 µg/L indicated the need for improving production techniques by the industry.

PRACTICAL APPLICATIONS

Studies have shown that the concentration of patulin may exceed the determined limits in apple juice and in other fruit products. Its presence can be a potential threat to the health of consumers, particularly children. The results may help us in understanding what should be the level of patulin in apple juice. The awareness of the apple industry of patulin contamination in fruit and the implementation of improved techniques for the production of apple products with reduced patulin concentrations have contributed to the quality of apple juice that are available on the Iranian market.
TOXICITY AND ANTIBACTERIAL EFFECT OF MACE OF MYRISTICA FRAGRANS USED IN MOROCCAN GASTRONOMY: BIOCHEMICAL AND HISTOLOGICAL IMPACT
Authors: EL MALTI JAZILA , BOURHIM NOUREDDINE , AMAROUCH HAMID
Published: July 2008

The aril of the plant Myristica fragrans is one of the most broadly used spices in Moroccan gastronomy. This research demonstrated its antimicrobial activity against both gram‐positive and gram‐negative bacterial species. Likewise, its toxicity was investigated on Swiss albino mice. Mice were treated orally with 0.003 and 0.3 mg/day during 7 days. Plasmatic markers and antioxidant defense systems were assessed and histological alterations evaluated. Our results showed a significant increase in creatine phosphokinase level. The microscopic evaluation showed that mace induces morphological perturbation in mice's liver. The results also showed an inhibitory effect of glyceraldehyde 3‐phosphate dehydrogenase and an important increase in the level of thiobarbituric acid reactive substances, succinate dehydrogenase activities and no change in catalase activities. All of these results show that M. fragrans at 0.3 mg/g in mice affects energy metabolism and oxidative stress.

PRACTICAL APPLICATIONS

Mace can be used as a natural antioxidant and preservative in the food industry to increase the shelf life of foodstuffs.
The Lingering Effects of the Recruitment Experience on the Long‐Term Employment Relationship
Authors: Ferguson Merideth , Moye Neta , Friedman Ray
Published: July 2008

Two studies (one cross‐sectional and one longitudinal) examine the effects that job negotiation interactional justice perceptions created in the recruitment process have on an employee’s turnover intentions. The findings indicate a long‐term impact of the interactional justice perceptions experienced in the recruitment negotiation on employees’ intent to leave their organization. Specifically, job negotiation interactional justice perceptions have a lingering effect on an individual’s turnover intentions beyond the effects of distributive justice and supportive human resource practices.
Early detection of psychosis: finding those at clinical high risk
Authors: Addington Jean , Epstein Irvin , Reynolds Andrea , Furimsky Ivana , Rudy Laura , Mancini Barbara , McMillan Simone , Kirsopp Diane , Zipursky Robert B.
Published: July 2008

Aim: In early detection work, recruiting individuals who meet the prodromal criteria is difficult. The aim of this paper was to describe the development of a research clinic for individuals who appear to be at risk of developing a psychosis and the process for educating the community and obtaining referrals.

Methods: The outcome of all referrals to the clinic over a 4‐year period was examined.

Results: Following an ongoing education campaign that was over inclusive in order to aid recruitment, approximately 27% of all referrals met the criteria for being at clinical high risk of psychosis.

Conclusions: We are seeing only a small proportion of those in the community who eventually go on to develop a psychotic illness. This raises two important issues, namely how to remedy the situation, and second, the impact of this on current research in terms of sampling bias and generalizability of research findings.
Numerical Wave Tanks Based on Finite Element and Boundary Element Modeling
Authors: Taylor R. Eatock , Wu G. X. , Bai W. , Hu Z. Z.
Published: July 2008

This work forms part of an investigation into the nonlinear interaction between steep (but not overturning) transient waves and flared structures, using a coupled finite element and boundary element model. The use of a coupled approach is based on consideration of the relative strengths and weaknesses of the finite element (FE) and boundary element (BE) methods when implemented separately (e.g., efficiency of computation versus complexity of adaptive mesh generation). A FE model can be used to advantage away from the body, where the domain is regular, and a BE discretization near the body where the moving mesh is complex. This paper describes the aspects of the FE and BE models which have been developed for this analysis, each based on the use of quadratic isoparametric elements implemented in a mixed Eulerian–Lagrangian formulation. Initially, the two approaches have been developed side by side, in order to ensure the use of robust components in the coupled formulation. Results from these methods are obtained for a series of test cases, including the interaction of an impulse wave with a circular cylinder in a circular tank, and nonlinear diffraction by a cylinder in a long tank.
Nonlinear Effects on Fatigue Analysis for Fixed Offshore Structures
Authors: Gaidai Oleg , Naess Arvid
Published: July 2008

Fatigue analysis for fixed offshore structures is an important practical issue. These structures are often drag dominated, which makes the deck response a non-Gaussian process when it is assumed that the irregular waves are Gaussian. Incorporating nonlinear and non-Gaussian modeling in the fatigue analysis can be a complicated issue, cf. work of Madhavan Pillai and Meher Prasad [2000, “Fatigue Reliability Analysis in Time Domain for Inspection Strategy of Fixed Offshore Structures,” Ocean Eng., 27(2), pp. 167–186]. The goal of this paper is to provide evidence that for drag dominated offshore structures it is, in fact, sufficient to perform linearization in order to obtain accurate estimates of fatigue damage. The latter fact brings fatigue analysis back into the Gaussian domain, which facilitates the problem solution. Beyond straightforward linearization of the exciting wave forces, this paper employs two different approaches accounting for nonlinear effects in fatigue analysis. One is an application of the quadratic approximation approach described in the work of Naess and co-workers [1997, “Frequency Domain Analysis of Dynamic Response of Drag Dominated Offshore Structures,” Appl. Ocean. Res., 19(3), pp. 251–262;1996, “Stochastic Response of Offshore Structures Excited by Drag Forces,” J. Eng. Mech., ASCE, 122, pp. 155–160]. to the stochastic fatigue estimation of jacket type offshore structures. An alternative method proposed is based on a spectral approximation, and this approximation turns out to be accurate and computationally simple. The stress cycles causing structural fatigue are considered to be directly related to the horizontal excursions of the fixed offshore structure in random seas. Besides inertia forces, it is important to study the effect of the nonlinear Morison type drag forces. Since no direct method for dynamic analysis with Morison type forces is available, it is a goal to find an accurate approximation, allowing efficient dynamic analysis. This has implications for long term fatigue analysis, which is an important issue for design of offshore structures.
A Physical and Numerical Modeling for Launching of Jackets (Case Study on Balal PLQ Platform)
Authors: Honarvar M. R. , Pirooz Moharam D. , Bahaari Mohammad R.
Published: July 2008

Platform structures are commonly utilized for various purposes including offshore drilling, processing, and support of offshore operations. A jacket is a supporting structure for deck facilities, stabilized by piles driven through it to the seabed. In a jacket design, operational and environmental loads are very important and must be intensively investigated to secure the stability of structures during their service life, as well as installation phase. The main purpose of this research is to evaluate the results of physical modeling for the launch operation of jackets from barge into the sea, as the most hazardous stage in the installation of a platform, and compare them to those of numerical modeling. Both physical and numerical modeling parameters are described and they are examined on a prototype platform, i.e., Balal oil field production and living quarter platform that is a 1700 tone, eight-legged jacket located in the center of Persian Gulf, some 100km distance from Iranian Lavan Island. It is found that both numerical and physical methods can describe the motion of the barge similarly well, but some differences are traced in the motion of jacket. The inequalities are, then, appeared to be due to the Froude-type parameters applied for modeling purpose. One notable fact investigated in this research is the necessity for choosing Reynolds–Froude type in the physical modeling of the launch, instead of Froude type. This is because, in addition to the importance of gravitational and inertial forces, the viscosity affects the drag hydrodynamic force, as well. It should be noted that viscosity and consequently drag coefficient in Froude type modeling cannot be quite applicable and this causes the difference observed between the results of physical and numerical modeling. Although there have been so many jacket launching designed and probably their physical models have been tested, but to the best of our knowledge from the literature, there was found no study on Reynolds–Froude physical modeling of jacket launch phenomenon. If one is interested in practicing a Reynolds-Froude physical modeling, it could be done either in a centrifuge test or by using a fluid with lower viscosity dependent on the scale of model, or even by finding a fluid (with new viscosity and new density) and a new gravity to have simultaneously the Froude and the Reynolds similarity laws satisfied.
Delamination at Thick Ply Drops in Carbon and Glass Fiber Laminates Under Fatigue Loading
Authors: Samborsky Daniel D. , Wilson Timothy J. , Agastra Pancasatya , Mandell John F.
Published: July 2008

Delamination at ply drops in composites with thickness tapering has been a concern in applications of carbon fibers. This study explored the resistance to delamination under fatigue loading of carbon and glass fiber prepreg laminates with the same resin system, containing various ply drop geometries, and using thicker plies typical of wind turbine blades. Applied stress and strain levels to produce significant delamination at ply drops have been determined, and the experimental results correlated through finite element and analytical models. Carbon fiber laminates with ply drops, while performing adequately under static loads, delaminated in fatigue at low maximum strain levels except for the thinnest ply drops. The lower elastic modulus of the glass fiber laminates resulted in much higher strains to produce delamination for equivalent ply drop geometries. The results indicate that ply drops for carbon fibers should be much thinner than those commonly used for glass fibers in wind turbine blades.
The Inverse Vortex Wake Model: A Measurement Analysis Tool
Authors: Haans Wouter , van Kuik Gijs , van Bussel Gerard
Published: July 2008

To reduce the level of uncertainty associated with current rotor aerodynamics codes, improved understanding of rotor aerodynamics is required. Wind tunnel measurements on model rotors contribute to advancing our knowledge on rotor aerodynamics. The combined recording of blade loads and rotor wake is desired, because of the coupled blade and wake aerodynamics. In general, however, the small size of model rotors prohibits detailed blade load measurements; only the rotor wake is recorded. To estimate the experimental blade flow conditions, a measurement analysis tool is developed: the inverse vortex wake model. The rotor wake is approximated by a lifting line model, using rotor wake measurements to reconstruct the vortex wake. Conservation of circulation, combined with the Biot–Savart law, allows the induced velocity to be expressed in terms of the bound circulation. The unknown bound circulation can be solved for, since the velocity is known from rotor wake measurements. The inverse vortex wake model is subsequently applied to measurements on the near wake of a model rotor subject to both axial and yawed flow conditions, performed at a TUDelft open jet wind tunnel. The inverse vortex wake model estimates the unsteady experimental blade flow conditions and loads that otherwise would have remained obscured.
Assessment of Condition Monitoring Techniques for Offshore Wind Farms
Authors: Wiggelinkhuizen Edwin , Verbruggen Theo , Braam Henk , Rademakers Luc , Xiang Jianping , Watson Simon
Published: July 2008

This paper discusses the results of an extensive investigation to assess the added value of various techniques of health monitoring to optimize the maintenance procedures of offshore wind farms. This investigation was done within the framework of the EU funded Condition Monitoring for Offshore Wind Farms (CONMOW) project, which was carried out from 2002 to 2007. A small wind farm of five turbines has been instrumented with several condition monitoring systems and also with the “traditional” measurement systems for measuring mechanical loads and power performance. Data from vibration and traditional measurements, together with data collected by the turbine’s system control and data acquisition (SCADA) systems, have been analyzed to assess (1) if failures can be determined from the different data sets; (2) if so, if they can be detected at an early stage and if their progress over time can be monitored; and (3) if criteria are available to assess the component’s health. Several data analysis methods and measurement configurations have been developed, applied, and tested. This paper first describes the use of condition monitoring if condition based maintenance is going to be applied instead of only scheduled and corrective maintenance. Second, the paper describes the CONMOW project and its major results, viz., the assessment of the usefulness and capabilities of condition monitoring systems, including algorithms for identifying early failures. Finally, the economic consequences of applying condition monitoring systems have been quantified and assessed.
Reliability of Wind Turbine Technology Through Time
Authors: Echavarria E. , Hahn B. , van Bussel G. J. W. , Tomiyama T.
Published: July 2008

This study attempts to obtain more detailed knowledge of failures of wind turbines (WTs) by using the German “250MW Wind” test program database. Specific objectives are to show the reliability of some major components and to analyze how their design has advanced through time, what the main failures are, and which technologies have proven to work. Within the program, reports on operation and maintenance are analyzed with respect to WT type, size, and technologies used. This paper presents a comparison of component reliability through time, with respect to their technology. The results show significant differences in reliability for certain subcomponents depending on the size of the WT and especially on the type of power control. For instance, induction generators show half the annual failure rate compared to synchronous generators. The study also includes failures of other components that are affected or added due to the use of the components being analyzed. In general, the results show that failure rates of WTs decrease with time. Most of the data show a short period of “early failures” and later a long period of “random failures.” However, this is not the case for the megawatt class: As technology is introduced into the market, WTs show a longer early failure behavior, which has not yet become stable. Furthermore, large turbines, included in the database analyzed, show a significantly higher annual failure rate of components, per WT. This may be due to the immature technology of the WTs included in the database.
SU‐DD‐A1‐06: Correlation Between Number of Beams and Monitor Units, in the Context of VMAT and RapidArc, in IMRT
Authors: Fu L , Das I
Published: July 2008

Purpose: Reduction in treatment time and monitor units (MU) are desired for an optimum intensity modulated radiotherapy (IMRT) plan. We investigated the relationship between increasing field numbers and the total number of monitor units and segments in IMRT plans of prostate cancer tumors, and its impact on arc techniques such as intensity modulated arc therapy (IMAT) and volumetric modulated arc therapy (VMAT). Method and Materials: Ten prostate cancer patients treated to the same clinical protocol of 79.2 Gy were investigated. Individual plans that consisted of 5, 7, 9, 18 and 36 equally spaced, 15 MV beams were created for each patient. The effect of beam numbers on each plan was analyzed for 1) PTV Uniformity Index, 2) Segments, 3) Monitor Units (MU) and 4) DVH of all organs. Results: MU changes were most significant when number of fields increased from 5 to 9. Number of segments showed similar trends, where maximum increase in segment numbers occurred when field numbers increased from 5 to 9. The UI results showed both increasing and decreasing trends when field numbers increased between different patients, but were not significant. DVH comparison of organs at risk showed maximum changes in volume dose when the number of fields increased from 5 to 7. Conclusion: Increasing the field numbers from 9 to 36 fields did not result in dramatic changes in MU, segments, uniformity or DVH. Our study showed that for traditional IMRT step and shoot arrangements, to achieve similar homogeneous coverage of deep seated tumors, significant increases in the number of fields did not result in similar increases in monitor units or segments. Provided the continuous beam‐on and segment changes do not affect the overall treatment delivery speed, techniques based on modulated arc therapy should deliver dose distributions similar to IMRT techniques in considerably less time.
SU‐DD‐A2‐01: The Metal Artifact Reduction Technique for Accurate Prostate Seed Localization Using Limited EPID Projections and Deformable Registration
Authors: Chang J , Suh T , Jung W , Park S
Published: July 2008

Purpose: Scatter radiation can degrade the quality of a kilovoltage cone‐beam CT (KV CBCT) image due to the use of a larger flat‐panel detector. Especially, if KV CBCT is employed for seed localization, the effect of streak metal artifacts of the seeds can be magnified in CBCT images. In this study, we describe the preliminary application of MV cone‐beam reconstruction (CBR) image from EPID projections and deformable registration for metal artifact reduction in a test phantom. Method and Materials: To perform the CBR and deformable registration based technique, the following three steps were used. (1) Extract a seeds only image and an image of seeds with bright metal streak regions by using a user‐defined threshold value in the CBR image and KV CBCT images. (2) A derived intensity based 3D ‘demon’ deformable registration algorithm was applied to both seeds images, and the use of the algorithm generated the deformation field. (3) Resample the original CT image according to the deformation field. Results: The intensities of the metal artifact region were decreased with the use of the deformation grid, as the seeds in KV CBCT images were deformed as compared to the original seeds in CBR images. Although image quality was not dramatically enhanced, the metal artifact removed volume which causes the dose calculation error was 2.795 mm3 over 61 CT slices of the test phantom. Conclusion: Preliminary results with a test phantom demonstrated a bright streak metal artifact reduction effect. We believe that if dose calculation associated with KV CBCT yields reliable results, our study could provide an efficient method for post‐implant dosimetry. Conflict of Interest: This research sponsored by the Seoul R&BD Program (10550) and the Mid‐ and Long‐Term Nuclear R&D Program of the Ministry of Science and Technology (M20706000007‐07M0600‐00710).
SU‐DD‐A2‐02: Accurate Dosimetric Characterization of a Novel 125I Eye Plaque Design
Authors: Trichter S , Zaider M , Munro J , Sabbas A , Nori D
Published: July 2008

Purpose: Eye plaques provide a good alternative to enucleation for ophthalmic tumors. The majority of eye plaques in the U.S. use brachytherapy seeds in a Collaborative Ocular Melanoma Study (COMS) standardized design. The plaques are 3 mm thick and uncomfortable to the patients, dosimetrically having localized hot spots. Implant Sciences developed 1 mm thick eye plaques using ion‐implantation techniques. Dosimetric characterization of prototype plaques using radiochromic film and a silicon diode is reported. Method and Materials: Prototype 16 mm eye plaques consisted of titanium‐encapsulated hemispheric quartz substrates with an layer at the inner surface, and a gold backing. Dosimetry was performed using GAFCHROMIC XR‐T and EBT film in a specially designed Solid Water “eye” phantom inserted into a 30 cm × 30 cm × 23 cm full scatter Solid Water phantom, as well as using a Scanditronix stereotactic diode in a water tank. Films were sandwiched between 1 mm thick phantom inserts perpendicular to the plaque's central axis. The diode was used for point measurements along the central axis and scans across the plaques. The films and diode were calibrated using a calibrated I‐Plant 3500 seed in Solid Water and water respectively, applying the TG‐43 formalism. Results: Dose distributions in planes perpendicular to the central axis of the plaques were radially isotropic and uniform. Film results, reproducible within 4%, agree well with silicon‐diode measurements. At 5 mm depth, measured dose rates are between 50 and 200 cGy/hour. Conclusion: Implant Sciences' ion‐implantation technique enables manufacturing of thin eye plaques with optimal dose distributions and clinically‐useful dose rates. GAFCHROMIC film in a Solid Water phantom and the stereotactic diode in water are convenient and reproducible dosimeters for eye plaque dosimetry. Conflict of Interest: Supported in part by SBIR NIH Grant 2R44CA092913‐02.
SU‐DD‐A2‐06: TG‐43 Parameterization of a Novel Brachytherapy Source Design of Multi‐Radioisotope
Authors: Dini S , Warren G , Meigooni A
Published: July 2008

Purpose: Applications of I‐125 and Pd‐103 sources in brachytherapy treatment of prostate cancers, with long and short doubling time, respectively, are well established. However, for treatment of prostate cancer composed of cells with different doubling time, a brachytherapy source with mixture of I‐125 and Pd‐103 radioisotopes might be more desirable. In this project, dosimetric characteristics of a novel brachytherapy source, composed of a mixture of I‐125 and Pd‐103 radioisotopes, has been determined following AAPM TG‐43U1 protocol. Method and Materials: A new brachytherapy source model, ADVANTAGE™ HYBRID PdI, has been designed by IsoAid™, LLC for treatment of prostate cancer. A dose calculation model was developed to determine the dosimetric characteristics of this source design. In this model, the Monte Carlo simulated parameters from each isotope of the source were individually determined assuming 50% dose contribution from each isotope. These values were then utilized for determination of the parameters of the mixed source. The outcomes of these investigations have been incorporated in the VariSeed planning system for the evaluation of an actual clinical case. Results: The results of these investigations indicated that the dose rate constant of a source with 50% dose contribution from each isotope is 0.699 cGy/hr/U. The radial dose function, 2D‐ and 1D‐ anisotropy function of the new source design have been tabulated for clinical applications. The tolerance of each parameter was evaluated for isotope variation within the source. The percent variation of V100 and D90 were found to be less than 1% and 4%, respectively, which are within the acceptable range. Conclusion: The TG‐43 dosimetric parameters of a multi‐isotope source have been determined for clinical applications in the treatment of prostate cancer with tumors composed of cells with variety of potential doubling times.

This project is partially sponsored by IsoAid™, LLC.
SU‐DD‐A3‐04: Analysis of Prostate Patient Setup Error and Organ Motion Error Using Calypso Setup Shift and Tracking Data
Authors: Su Z , Farukhi Y , Murphy M , Williamson J
Published: July 2008

Purpose: To evaluate the prostate patient setup and intra‐fraction organ motion error distributions by analyzing initial setup shift and target tracking data obtained from the Calypso system. Method and Materials: The spatial coordinates of the centroid of three implanted markers implanted in the prostates of 13 patients were monitored by our Calypso system with 10Hz sampling frequency. Patients were initially setup to tattoos and then shifted to the Calypso localized locations. Measurements were performed for average 32 fractions of average time about 8 minutes each. For each patient, the systematic setup correction and standard‐deviation (SD) over all fractions was obtained for the left‐right (LR), anterior‐posterior (AP) and superior‐inferior (SI) axes. Systematic setup error was obtained as the SD of the systematic setup errors of all patients. Similarly, the systematic and random components of prostate intra‐fractional motion were obtained from the tracking data. For all patients, correlation coefficients were calculated among the three axes of tracking data; the cumulative probability of total 3D displacement from initial setup was also calculated. Results: The systematic and random components of the initial setup errors for LR, AP and SI axes are 2.4mm, 2.6mm and 3.2mm, respectively and 3.6mm, 2.7mm and 3.3mm. The corresponding systematic and random components of prostate intra‐fractional motion errors are 0.3mm, 0.5mm and 0.6mm, and 0.6mm, 1.1mm and 1.0mm, respectively. The correlation between AP and SI motion was significant. The 3D displacement data indicates that 11 of 13 patients have 94.4% or higher probability of prostate motion within 5mm from the Calypso setup positions. However, one patient showed 28.7% probability of motion beyond 5mm. Conclusion: In our patient population, residual systematic and random error due to intra‐fraction prostate motion is small, once inter‐fraction setup‐organ motion errors have been eliminated by Calypso‐guided online setup.

Supported in part by grant P01 CA 116162.