bluuebunny/crossref_metadata_2025 huggingface dataset:
Eight genotypes (A–H) of hepatitis B virus infecting patients from San Francisco and their demographic, clinical, and virological characteristics
Authors: Kato Hideaki , Gish Robert G. , Bzowej Natalie , Newsom Margaret , Sugauchi Fuminaka , Tanaka Yasuhito , Kato Takanobu , Orito Etsuro , Usuda Sadakazu , Ueda Ryuzo , Miyakawa Yuzo , Mizokami Masashi
Published: June 2004

Clinical lines of evidence have been accumulated that hepatitis B virus (HBV) genotypes have characteristic geographical distributions and distinct clinical impact on liver diseases. The distribution of HBV genotypes was determined with reference to hepatitis B e antigen (HBeAg) and alanine aminotransferase (ALT) levels in 165 patients with hepatitis B in San Francisco. HBV genotypes were determined by enzyme‐linked immunosorbent assay (ELISA) and the unclassified samples were sequenced within the S region for phylogenetic analysis. Genotype A occurred in 60 (36%) patients, B in 16 (10%), C in 56 (34%), D in 19 (12%), E in 1 (1%), F in 1 (1%), G in 8 (5%), and H in 4 (2%). Caucasians were infected predominantly with HBV genotype A (HBV/A) (38 of 57 [67%]), Asians with HBV/C (45 of 63 [71%]), and Hispanics with HBV/F and HBV/H (4 of 9 [44%]). Serum ALT levels were higher in the patients infected with HBV/A (P = 0.03) or HBV/G (P = 0.02) than HBV/C. HBeAg was more frequent in patients infected with HBV/G than HBV/C or HBV/D (7 of 8 [88%] vs. 25 of 56 [45%] or 6 of 19 [32%], P = 0.03 or 0.01). In conclusion, eight genotypes (A–H) were identified in San Francisco in association with various ethnicities and then influenced ALT levels as well as the prevalence of serum HBeAg. HBV genotype H might be identified by combination of preS2 serotpe bksf and HBsAg serotype adw. J. Med. Virol. 73:516–521, 2004. © 2004 Wiley‐Liss, Inc.
Seroprevalence of markers of viral hepatitis in Yemeni healthcare workers
Authors: Shidrawi Ray , Ali Al‐Huraibi Mohammed , Ahmad Al‐Haimi Mohammed , Dayton Ralph , Murray‐Lyon Iain M.
Published: June 2004

The seroprevalence of viral hepatitis in healthcare workers has important public health implications. To assess the risk factors for the acquisition of viral hepatitis in an unvaccinated cohort from an hyperendemic region, 567 healthcare workers from a large hospital in the capital of the Republic of Yemen were interviewed and tested for serological markers of infection with viral hepatitis. 54/543 (9.9%) tested positive for hepatitis B surface antigen (HBsAg), 174/543 (32.0%) had positive hepatitis B core antibodies (anti‐HBc), and 19/546 (3.5%) had hepatitis C antibodies (anti‐HCV). Age (OR = 1.04, 95% CI 1.02–1.06), male sex (OR = 2.0, 1.32–3.03), and occupation (healthcare workers not carrying out exposure prone procedures, OR = 1.61, 1.06–2.44) were found to be independent predictors for the likelihood of detecting either HBsAg or anti‐HBc by multivariate logistic regression analysis. No independent risk factors for anti‐HCV positive status were identified. Our findings support the adoption of universal HBV immunisation programmes and infection control precautions. The absence of known risk factors predicting anti‐HCV positive serostatus suggests the main mode of transmission of hepatitis C in this cohort in the Yemen remains undiscovered. J. Med. Virol. 73:562–565, 2004. © 2004 Wiley‐Liss, Inc.
Excess hospital admissions for pneumonia, chronic obstructive pulmonary disease, and heart failure during influenza seasons in Hong Kong
Authors: Yap Florence H.Y. , Ho Pak‐Leung , Lam Kwok‐Fai , Chan Paul K.S. , Cheng Yeung‐Hung , Peiris Joseph S.M.
Published: June 2004

It is widely held that Southern China is a hypothetical influenza epicentre for the emergence of pandemic influenza viruses. However, influenza is perceived as a relatively unimportant infection in this part of the world compared with western countries. Hong Kong is situated within the hypothetical epicentre and serves as a sentinel post for the region. In a retrospective study, the influenza‐associated excess hospitalisations in a regional hospital for pneumonia, chronic obstructive pulmonary disease (COPD), heart failure, and asthma in persons aged ≥65 years from 1998 to 2001 were each estimated by a model taking into consideration the confounding effect of other respiratory viral infections, seasonal factors, time trends, and weather and pollution indices. In the regression models, influenza activity is an independent significant factor affecting admission rates for pneumonia, COPD, and heart failure but not that for asthma. The variations in hospital admissions for pneumonia, COPD, and heart failure explained by influenza activity were 38.9, 7.5, and 45.6%, respectively. The adjusted rates of excess influenza‐associated hospital admissions for the three diagnoses combined amounted to 58.5, 20.0, 29.2, and 13.4 per 10,000 populations aged ≥65 years in 1998, 1999, 2000, and 2001, respectively. In conclusion, influenza activity is associated significant excess hospital admissions among elderly aged 65 or above in Hong Kong, comparable to the data reported in Western countries. The findings support a wider application of annual influenza vaccination in this region. J. Med. Virol. 73:617–623, 2004. © 2004 Wiley‐Liss, Inc.
Are false negative direct immnufluorescence assays caused by varicella zoster virus gE mutant strains?
Authors: Taha Yusri A. , Quinlivan Mark , Scott Fiona T. , Leedham‐Green Mary , Hawrami Khidir , Thomas Janice M. , Breuer Judith
Published: June 2004

Strains of Varicella zoster virus (VZV) have been described recently in which a single base mutation in the gE epitope abrogates binding of the 3B3 monoclonal antibody, which is widely used for virus detection in diagnostic laboratories. These strains, named VZV‐MSP, are associated with a distinct phenotype in both in vitro culture and in SCID‐hu mice. We investigated the possibility that negative direct immunofluorescence results, using the 3B3 antibody, where the presence of virus was confirmed by polymerase chain reaction (PCR) or tissue culture are due in some cases to the MSP strain of VZV. A total of 249 vesicle fluid specimens from people with suspected shingles were examined using direct immunofluorescence, tissue culture and a nested multiplex PCR for VZV, herpes simplex virus type 1 (HSV‐1) and 2 (HSV‐2). VZV was detected in 218 of 249 (87.6%) cases. Forty‐five confirmed VZV specimens, but with negative (30) or indeterminate (15) immunofluorescence results, were analysed further. PCR was used to amplify a fragment in ORF 68 that encodes the VZV gE ectodmain recognised by 3B3 antibody. The fragments were sequenced and analysed for the single base change G448A (D150N), which is present in VZV‐MSP as compared with the reference Dumas strain. No VZV gE mutant (MSP/MSP‐like) was detected. Overall, PCR was found to be the most sensitive method of confirming VZV infection. False negative VZV immunofluorescence results are unlikely to be due to virus variants. J. Med. Virol. 73:631–635, 2004. © 2004 Wiley‐Liss, Inc.
Stability of ascorbic acid in adapted milk‐based infant formulae during storage
Authors: Manglano Pilar , Farré Rosaura , Lagarda María Jesús , Abellán Pedro , Romero Fernando , Clemente Gonzalo
Published: June 2004

A study was made of the effects of storage (for up to 17 months at 22 or 37 °C) on the ascorbic acid contents of four adapted milk‐based infant formulae with the same composition except for the iron salt added (lactate or sulphate) and/or the vitamin E source involved (α‐tocopherol (α‐T) or α‐tocopherol acetate (α‐TAc)). Ascorbic acid was measured by a voltammetric method. The ascorbic acid contents of the formulae ranged from 0.77–0.84 g kg−1 immediately after manufacture to 0.41–0.48 g kg−1 after 17 months of storage. Samples stored at 22 °C had higher ascorbic acid contents than those stored at 37 °C. A multiple regression analysis performed to evaluate ascorbic acid evolution throughout storage/shelf‐life and the effects of storage temperature and the different components of the samples yielded a model explaining 79.71% of the variability in ascorbic acid content. Iron lactate and α‐tocopherol acetate addition afforded the best preservation of ascorbic acid content. The evolution of ascorbic acid was not linear, exhibiting an important decrease in the first month of storage, followed by stabilisation. Copyright © 2004 Society of Chemical Industry
The relationship between gas transport properties and the histology of apple
Authors: Schotsmans Wendy , Verlinden Bert E , Lammertyn Jeroen , Nicolaï Bart M
Published: June 2004

The relation between skin resistance to gas diffusion, diffusivity and several histological characteristics of apple cvs Braeburn and Jonica was investigated. Large discrepancies were found between the skin resistance values measured by the efflux method and a diffusion method. It is believed that these discrepancies are due to the invalidity of Graham's law in tightly packed tissue, the existence of internal gas gradients and the types of tissue measured in the two methods. The differences between cultivars in diffusivity of O2 and CO2 in the same tissue were related to differences in intercellular space volume and cell size. The spatial pattern of the diffusivity of oxygen and carbon dioxide could be linked to the number of cells, the cell area, the cell perimeter and the internal free space volume. The considerably lower diffusivity in the skin was believed to be caused by both the skin and the very dense tissue of the outer cortex. Changes in diffusivity during storage coincided with changes in the amount of intercellular space and in the shape of the cells. Copyright © 2004 Society of Chemical Industry
Effect of essential oils of cinnamon, clove, lemon grass, oregano and palmarosa on growth of and fumonisin B1 production by Fusarium verticillioides in maize
Authors: Velluti Andrea , Sanchis Vicente , Ramos Antonio J , Marín Sonia
Published: June 2004

The ability of cinnamon, clove, lemon grass, oregano and palmarosa essential oils to prevent growth of and fumonisin B1 (FB1) production by Fusarium verticillioides at different water activity (0.95 and 0.995 aw) and temperature (20 and 30 °C) levels in irradiated maize grain was evaluated. All the essential oils inhibited growth of F verticillioides isolates under all conditions tested, but FB1 production was only inhibited at 30 °C and 0.995 aw. Moreover, stimulation of toxin production was found under certain environmental conditions. None of the essential oils showed a significantly greater ability to inhibit FB1 production when compared with the others. At 1000 mg essential oil kg−1 maize the essential oils showed a greater inhibitory effect on growth of F verticillioides than at 500 mg kg−1, but there was no difference in FB1 production between the two levels of essential oil. Copyright © 2004 Society of Chemical Industry
Nutritional study of raw and popped seed proteins of Amaranthus caudatus L and Amaranthuscruentus L
Authors: Gamel Tamer H , Linssen Jozef P , Alink Gerrit M , Mosallem Ahmed S , Shekib Lila A
Published: June 2004

The nutritional value of raw and popped (similar to popcorn preparation) seed proteins of two amaranth species, Amaranthus caudatus L and A cruentus L, was investigated. After popping, the true protein content in A caudatus and A cruentus decreased by 9 and 13% respectively. Among the amino acids, the loss of tyrosine due to the popping effect was the highest, followed by phenylalanine and methionine. Leucine was the first limiting amino acid in the raw samples, followed by lysine, while the reverse order was observed in the popped samples. The in vivo protein quality of raw and popped seeds was tested with male weanling rats and compared with wheat flour and casein samples. There was no difference between the in vivo digestibility of the raw and the popped seeds, although the in vitro digestibility was slightly higher for the popped samples. The protein efficiency ratio (PER) for all the amaranth seed samples was higher than that for the wheat sample, while the PER for the raw amaranth seed samples was close to that for the casein reference protein. The rat blood serum levels of total cholesterol, triglycerides and high‐density lipoprotein cholesterol for all the amaranth samples were lower than those for the reference protein, while the wheat flour sample showed the lowest values. Copyright © 2004 Society of Chemical Industry
Performance of dairy cows fed roasted sunflower seed
Authors: Sarrazin P , Mustafa AF , Chouinard PY , Raghavan GSV , Sotocinal SA
Published: June 2004

The objectives of this study were to determine the effects on milk yield, milk composition, ruminal fermentation and total tract nutrient utilization of feeding roasted whole sunflower seed to dairy cows. Three diets were formulated: a control diet with no sunflower seed (NSF), a raw sunflower seed diet (USF) and a roasted sunflower seed diet (RSF). The level of sunflower seed in USF and RSF was 78 g kg−1 of dry matter (DM). The effects of dietary treatments on yield and composition of milk were determined using nine Holstein cows in three 3 × 3 Latin squares. Three ruminally fistulated cows were used to determine the effects of dietary treatments on ruminal fermentation and total tract nutrient digestibilities. Cows fed sunflower seed diets consumed 8% less (P < 0.05) DM but produced similar amounts of milk as cows fed NSF. However, milk fat content (30.7 vs 33.5 g kg−1) and yield (1.33 vs 1.47 kg day−1) were lower (P < 0.05) for cows fed USF and RSF than for those fed NSF. Supplemental sunflower seed had no effect on concentrations and yields of other milk components. The concentrations of short‐chain (C4:0 to C12:0) and medium‐chain (C14:0 to C16:0) fatty acids were, respectively, 27% and 29% lower (P < 0.05) while those of long‐chain fatty acids (C18:0 to C18:3) were 51% higher (P < 0.05) in the milk of cows fed USF and RSF than for cows fed NSF. Ruminal pH, ammonia N and total volatile fatty acids were not affected by dietary treatments. Feeding sunflower seed (USF or RSF) reduced (P < 0.05) the concentration of acetate and increased (P < 0.05) the concentration of propionate. Total tract nutrient digestibilities were not affected by sunflower seed supplementation or by heat treatment. Supplementing dairy cow diets with unheated or roasted sunflower seed improved the efficiency of milk production and increased concentrations of long‐chain and polyunsaturated fatty acids. Feeding sunflower seed at up to 78 g kg−1 of diet DM had no adverse effects on nutrient utilization. Roasting had no additional benefits on milk yield or milk fatty acid composition. Copyright © 2004 Society of Chemical Industry
Grapevine clones discriminated using stilbene synthase–chalcone synthase markers
Authors: Faria Miguel A , Beja‐Pereira Marisa , Martins Antero , Ferreira Margarida A , Nunes Maria Eugénia S
Published: June 2004

Touriga Nacional is the most popular Portuguese grapevine cultivar. After twenty years of clonal selection, highly recommended qualitative and productive clones have been identified. In the genus Vitis several molecular markers have been used to characterize genetic diversity at the DNA level, namely microsatellites, ISSR (inter simple sequence repeat), AFLP (amplified fragment length polymorphism), and stilbene synthase–chalcone synthase (StSy–CHS) markers.

In this work a novel pure DNA extraction methodology, which occludes the extract in an agarose matrix, thus allowing the removal of the remaining hydrophilic impurities, was used. An optimized and highly reproducible procedure for the detection of differences among Vitis vinifera L clones using the StSy–CHS gene family primer combination is described. With this methodology, 21 clones and a commercial cultivar, ‘Chardonnay’, were evaluated with three StSy–CHS markers. It was possible to obtain 14% discrimination within Touriga Nacional (TN) clones, identifying two different groups. The polyclonal origin of TN clones was previously verified with eight microsatellite markers. The methodology described could be used for clonal selection of grapevine cultivars. Copyright © 2004 Society of Chemical Industry
Assessment of iron bioavailability from twenty elite late‐maturing tropical maize varieties using an in vitro digestion/Caco‐2 cell model
Authors: Oikeh Sylvester O , Menkir Abebe , Maziya‐Dixon Bussie , Welch Ross M , Glahn Raymond P
Published: June 2004

An in vitro digestion/Caco‐2 cell model was used to assess iron bioavailability of twenty elite late‐maturing tropical maize varieties grown in three diverse agroecologies in West and Central Africa (WCA). Kernel‐iron concentration of the varieties, averaged across locations, varied from 19.2 to 24.4 mg kg−1, while mean kernel‐zinc concentration ranged between 19.4 and 24.6 mg kg−1. Significant differences in iron bioavailability were observed among varieties, but the environment had no significant effect. Mean bioavailable iron ranged between 14% below and 43% above the reference control variety, TZB‐SR. Variety DMR‐LSR‐Y with the highest concentrations of kernel‐iron and ‐zinc of 24–25 mg kg−1 across the three locations had a similar quantity of bioavailable iron as the reference control, TZB‐SR. In the long run this variety could be potentially effective in reducing iron deficiency because of its high kernel‐iron. The most promising varieties were Mid‐altitude STR synthetic and ACR91SUWAN‐1‐SRC1. They had kernel‐iron and ‐zinc levels of 22–24 mg kg−1 and bioavailable iron 24–36% higher than the reference control, TZB‐SR. Additional research is necessary to determine if the increases in kernel‐iron concentration and bioavailable iron observed in this study can significantly improve the iron status of individuals in WCA at risk for iron deficiency. Copyright © 2004 Society of Chemical Industry
Methemoglobin formation during laser induced photothermolysis of vascular skin lesions
Authors: Randeberg L.L. , Bonesrønning J.H. , Dalaker M. , Nelson J.S. , Svaasand L.O.
Published: June 2004

Background and Objective

Monitoring dynamic changes during laser induced photothermolysis of vascular skin lesions is essential for obtaining an optimal therapeutic result. Rapid photoinduced thermal damage occurs at a threshold temperature of about 70°C. It is therefore, relevant to identify markers to indicate if this threshold temperature has been reached. Methemoglobin, which is formed by a photo‐induced oxidation of hemoglobin, indicates that the temperature has reached this threshold value. This study presents a proof of concept of a method for monitoring the in vivo presence of methemoglobin immediately after laser exposure.

Study Design/Materials and Methods

The present study was designed to investigate the in vivo temperature dependence of hemoglobin absorption in the 450–800 nm spectrum range. In vivo diffuse reflectance measurements of port‐wine stain (PWS) and telangiectasia were performed prior to, and immediately after, laser treatment with a pulsed dye laser (PDL) at 585 nm wavelength.

Results

In vivo measurements following laser treatment of vascular skin lesions showed an immediate increase in the optical absorption of blood. This effect, caused by thermal stress, is a result of an increased dermal blood volume fraction and methemoglobin formation. The effect is light dose dependent, and reflectance spectra revealed methemoglobin formation in patients treated with fluences above 5 J/cm2 at 585 nm wavelength.

Conclusions

It was proved that methemoglobin can be measured in vivo by reflectance spectroscopy. Measurements of the average methemoglobin concentrations immediately after laser exposure may be a valuable diagnostic tool to verify that the blood temperature has been sufficiently high to induce thermal damage to the vessel wall. Lasers Surg. Med. 34:414–419, 2004. © 2004 Wiley‐Liss, Inc.
Laser‐assisted endoscopic third ventriculostomy for obstructive hydrocephalus: Technique and results in a series of 40 consecutive cases
Authors: Devaux Bertrand C. , Joly Luc‐Marie , Page Philippe , Nataf François , Turak Baris , Beuvon Frederic , Trystram Denis , Roux François‐Xavier
Published: June 2004

Background and Objectives

To report a case series of endoscopic third ventriculostomy (ETV) using laser in 40 consecutive patients with obstructive hydrocephalus.

Study Design/Materials and Methods

Under stereotactic and endoscopic guidance, multiple perforations in the ventricular floor using a 1.32 μm neodymium–yttrium/aluminum/garnet (Nd–YAG) or a 0.805 μm diode laser unit and removal of intervening coagulated tissue ensued with a 4–6 mm opening between third ventricle and basilar cisterns.

Results

The procedure could be completed in all cases. A transient complication occurred in five cases. In 39 patients (mean follow‐up 28 months), 31 (79%) had a favorable outcome. Failure occurred in six patients, requiring permanent shunting leading to complete recovery, and two patients remained in a poor clinical status despite ETV.

Conclusions

Laser‐assisted ETV is a safe and efficient procedure for the treatment of obstructive hydrocephalus. Laser is advantageous in cases of distorted anatomy and may reduce technical failures. Lasers Surg. Med. 34:368–378, 2004. © 2004 Wiley‐Liss, Inc.
Fractional Photothermolysis: A New Concept for Cutaneous Remodeling Using Microscopic Patterns of Thermal Injury
Authors: Manstein Dieter , Herron G. Scott , Sink R. Kehl , Tanner Heather , Anderson R. Rox
Published: June 2004

Background and Objectives

We introduce and clinically examine a new concept of skin treatment called fractional photothermolysis (FP), achieved by applying an array of microscopic treatment zones (MTZ) of thermal injury to the skin.

Study Design/Materials and Methods

Two prototype devices emitting at 1.5 μm wavelength provided a pattern of micro‐exposures with variable MTZ density. Effects of different MTZ densities were tested on the forearms of 15 subjects. Clinical effects and histology were assessed up to 3 months after exposure. Treatment of photoaged skin on the periorbital area in an additional 30 subjects receiving four treatments over a period of 2–3 weeks was also tested. Tissue shrinkage and clinical effects were assessed up to 3 months after treatment.

Results

Pattern densities with spacing of 250 μm or more were well tolerated. Typical MTZ had a diameter of 100 μm and penetrated 300 μm into the skin. Reepithelialization was complete within 1 day. Clinical effects were assessed over a 3‐month period. Histology at 3 months revealed enhanced undulating rete ridges and increased mucin deposition within the superficial dermis. Periorbital treatments were well tolerated with minimal erythema and edema. Linear shrinkage of 2.1% was measured 3 months after the last treatment. The wrinkle score improved 18% (P<0.001) 3 months after the last treatment.

Conclusions

FP is a new concept for skin restoration treatment. Safety and efficacy were demonstrated with a prototype device. Further clinical studies are necessary to refine the optimum parameters and to explore further dermatological applications. Lasers Surg. Med. 34:426–438, 2004. © 2004 Wiley‐Liss, Inc.
Laryngeal morphometry with a new laser ‘clip on’ device
Authors: Schade Goetz , Leuwer Rudolf , Kraas Mathias , Rassow Bernhard , Hess Markus M.
Published: June 2004

Background and Objectives

Qualitative laryngoscopic investigations belong to diagnostic routine in laryngology. Nevertheless, quantitative morphometric measurements of intralaryngeal structures have been difficult by now.

Study Design/Material and Methods

The development of a two‐point‐light projection method for endolaryngeal measurements that works with a double reflecting mirror and green laser light is shown.

Results

The laser beams that have a distance of exactly 2 mm are very well visible at the surface of laryngeal structures. The technique can be used during a routine videoendoscopic examination.

Conclusion

In our opinion this method enables accurate quantitative morphological measurement within the larynx that could be used even in clinical routine. The two‐point light projection technique helps to reduce former limitations of endoscopic investigations. Lasers Surg. Med. 34:363–367, 2004. © 2004 Wiley‐Liss, Inc.
Clinical evaluation of enhanced nonablative skin rejuvenation using a combination of a 532 and a 1,064 nm laser
Authors: Tan Mei‐Heng , Dover Jeffrey S. , Hsu Te‐Shao , Arndt Kenneth A. , Stewart Brigitte
Published: June 2004

Background and Objectives

Improvements in the physical signs of photoaging can be achieved by non‐invasive laser resurfacing procedures. To evaluate the effectiveness and safety of the Nd:YAG 1,064 nm and KTP 532 nm lasers for non‐invasive skin rejuvenation.

Study Design/Patients and Methods

Subjects requesting non‐invasive skin rejuvenation underwent two treatments with the 532 nm laser to one side of the face and with both lasers to the other side, followed by three treatments with the 1,064 nm laser to both sides. Skin characteristics were evaluated before, during, and up to 4 months after treatment.

Results

A >25% improvement in overall skin condition was observed for >30% of subjects at the 1 month follow‐up and >40% of subjects at the 4 month follow‐up. The greatest improvements were observed for visual dryness, roughness, and uneven pigmentation. No adverse events were reported. There was a trend for greater improvement in patients who received more 1,064 nm treatments but this was not statistically significant.

Conclusions

The 532 nm KTP and 1,064 nm Nd: YAG lasers can be effectively and safely used for non‐invasive skin rejuvenation. Lasers Surg. Med. 34:439–445, 2004. © 2004 Wiley‐Liss, Inc.
Electrically Conducting Gels Formed From Polyaniline/Ethylcellulose/m‐Cresol Ternary Solutions
Authors: González Ignacio , Vecino Mónica , Muñoz M. Eugenia , Santamaría Anton , Pomposo J. Adolfo
Published: June 2004

Summary: Polyaniline doped with camphorsulfonic acid (PANI‐CSA) and ethylcellulose (EC), constitutes the basis of the investigated binary PANI(CSA)0.5/m‐cresol and ternary PANI(CSA)0.5/EC/m‐cresol solutions. Ternary solutions give rise to gels with a lower elastic modulus and electrical conductivity than binary PANI(CSA)0.5/m‐cresol gels. However, the dimensional stability is considerably improved, since warping observed in binary gels is eliminated or lessened. These results are explained considering the role played by ethylcellulose, which interacts with the hydroxyl group of m‐cresol, skimping PANI(CSA)0.5/m‐cresol specific interactions and retarding solvent evaporation.

Electrical conductivity of binary (▴) and ternary (•) gels as a function of m‐cresol content. The arrow indicates that warping is observed below this solvent level.

magnified image

Electrical conductivity of binary (▴) and ternary (•) gels as a function of m‐cresol content. The arrow indicates that warping is observed below this solvent level.
Modified technique of ureteroureterostomy in rat kidney transplantation
Authors: Pietsch Alexander , Nett Philipp C. , Sollinger Hans W. , Hullett Debra A.
Published: June 2004

Different strain combinations of rats are available to study immunological and transplant‐related problems in the models of kidney transplantation. Although numerous modifications of surgical techniques for ureteric reconstruction are evaluated in order to reduce complications and to extend long‐term survival, ureteric complications still occur frequently, especially when the difference in diameter of both donor and host ureters is disproportionate. Instead of using the current nonsplinted ureteroureterostomy (method A), a versatile and rapid technical modification (method B) was developed to perform reconstruction of ureters with disproportionate diameters. The overall incidence of ureteric complications was 80% (8/10) using method A, whereas this rate was significantly reduced to 15% (3/20) using method B (P < 0.001). Our modification proves the feasibility of nonsplinted ureteroureterostomy in a technical, highly demanding rat model of kidney transplantation with an acceptable rate of ureteric complication, considering the disproportionate difference in diameter between the host and donor ureters. © 2004 Wiley‐Liss, Inc.
Oxidative stress–associated mitochondrial dysfunction in corticosteroid‐treated muscle cells
Authors: Oshima Yasushi , Kuroda Yukiko , Kunishige Makoto , Matsumoto Toshio , Mitsui Takao
Published: June 2004

We analyzed the effects of corticosteroid on mitochondrial membrane potentials (ΔΨm), generation of reactive oxygen species (ROS), and apoptosis in a human rhabdomyosarcoma cell line, RD, and a dopaminergic neuroblastoma cell line, SH‐SY5Y. The cell lines were cultured in the presence or absence of dexamethasone and superoxide dismutase (SOD) for up to 1 week. Dexamethasone treatment increased ΔΨm, ROS generation, and apoptosis in proliferating RD cells. Treatment with SOD attenuated ROS generation and apoptosis, but not ΔΨm. The increase in ΔΨm seemed to be the primary effect of dexamethasone on proliferating RD cells, which is probably mediated by mitochondrial transcription. In differentiated RD cells, but not differentiated SH‐SY5Y cells, dexamethasone treatment showed a delayed effect of interfering with the ΔΨm and increasing ROS generation and apoptosis. Since these changes disappeared in the presence of SOD, dexamethasone primarily induced ROS generation, resulting in apoptosis. We speculate that this mechanism provides the basis of a pathophysiological model of corticosteroid myopathy. Muscle Nerve 30:49–54,2004
Stochastic optimization for the ruin probability
Authors: Schäl Manfred
Published: June 2004

The Cramér‐Lundberg insurance model is studied where the risk process can be controlled by reinsurance and by investment in a financial market. The performance criterion is the ruin probability. The problem can be imbedded in the framework of discrete‐time stochastic dynamic programming. Basic tools are the Howard improvement and the verification theorem. Explicit conditions are obtained for the optimality of employing no reinsurance and of not investing in the market.
Phase Transitions in a Traffic Flow Model
Authors: Colombo Rinaldo M.
Published: June 2004

The terms phase transitions have been used since some years in the trafic modeling literarure to label a set of recurrent phenomena experimentally observed. This talk aims at the presentation of a system of p.d.e.s that models these phenomena, within the framework provided by phase transitions in systems of hyperbolic conservation laws.
Combining landmark and intensity driven registrations
Authors: Fischer Bernd , Modersitzki Jan
Published: June 2004

One of the challenging tasks in today image processing is image registration. Image registration is inevitable whenever images taken for example at different times or from different perspectives need to be compared or to be integrated. Typically, the location of corresponding points in the different views of one object or even of different objects is distorted. For example, motion or different properties of the underlying optical systems (MR, CT) are responsible for the distortion. Thus, a basic problem is to find a meaningful spatial transformation of a given image, such that the transformed image becomes similar to a given second one. Typically, the transformation is computed by minimizing a suitable similarity measure. For many applications it is also desirable to guide the registration by additional information, like the locations of outstanding points. In this note, be present a general variational based approach for image registration which allows the choice of a user supplied similarity measure and a user supplied regularizer as well as the integration of external knowledge, like, for example, the location of outstanding points.
3D‐Flow structures behind a circular cylinder with hemispherical head geometry
Authors: Leder A. , Grebin U. , Hassel E. , Kashkoul Y. , Ackl A.
Published: June 2004

An experimental investigation of the flow around a finite circular cylinder mounted on a flat plate, see fig. 1, is reported. The aspect ratio L/D (with length L and diameter D) of the cylinder model is 2.0. The focus of this study is toward examining the complex separated flow structures and wake properties. Velocity and turbulence measurements have been carried out with a three component Laser Doppler anemometer (LDA) at the Reynolds number ReD = 2.0 · 105. The experimental results show complex 3D fluid motions in the separated flow region. They are induced by the superposition of three main vortical flows.
An adaptive Lagrange‐Galerkin method for the shallow‐water equations on the sphere
Authors: Läuter Matthias
Published: June 2004

The shallow‐water equations on the sphere are compressible Navier‐Stokes equations that describe hydrostatic atmospheric dynamics. An adaptive Lagrange‐Galerkin method is applied on the spherical domain to develop a simplified global atmospheric model. Computational results show the experimental convergence of this numerical method.
Homogenization of cellular structures for soft tissue modelling
Authors: Rohan Eduard
Published: June 2004

The aim of the paper is to show how the method of homogenization can be applied in modelling of soft tissue undergoing large deformation. Simplified microstructures are considered, which consist of hyperelastic porous matrix and periodic array of fluid‐filled cells. At the microscopic level diffusion processes are described by the Darcy law, permeability of the cellular membrane is introduced. Although at the macroscopic scale the tissue is incompressible, the flow inside microscopic volumes induces viscous relaxation effects. The homogenized problem is formulated.
Simulating Prosthetic Gait ‐ Lessons to Learn
Authors: Brugger P. , Schmiedmayer H.‐B.
Published: June 2004

Modern computer assisted above knee prostheses currently available on the market (e.g. C‐Leg from Otto‐Bock) allow the patients to choose their walking speed freely during level walking. Due to energy reasons it is only possible to change the passive mechanical characteristics of the prosthetic limb but no active actuators can be used to influence the knee joint movement. The control strategies for level walking act on the damping of the knee joint during swing phase of gait. During walking down ramps or descending stairs the control strategies are switched off in current designs. Based on a measured reference kinematics it should be possible to study the influence and behaving of technical devices in combination with the whole body biomechanical system. For this purpose we use a combined inverse‐forward‐dynamics approach. Kinematics parameters that are not critical in the inverse‐dynamics approach (leading to physiological reasonable forces and moments) and that are not influenced by the other parameters in the model are prescribed as in the classical inverse‐dynamics approach. To follow the other kinematics parameters (joint‐angles) control elements are used where the associated joint‐moments are determined by the goal trajectory and physiological boundary conditions. The so called “controlled joints” of the model and the applied technical device (prosthesis) are formulated as a forward‐dynamics system. In contrast to experimental studies a simulation study offers the advantage, that parameters can be varied in a wide range. Different ramp and stair inclinations can be implemented and different control strategies can be tested without any risk for the patient. The disadvantage lies in the fact, that there are only few reference sets for the kinematics of real patients. The modification of a reference kinematics for different situations (level walking, ramp or stair descent) is a big challenge and needs further investigation. On the other hand the combined inverse‐forward‐dynamics approach with its well balanced simplicity and complexity offers a flexible tool to reach this aim. This approach can also be used to investigate the interaction of the biomechanical system with other technical systems like sports equipment.
The optimal elbow angle for acrobatics ‐ stability analysis of the elbow with a load
Authors: Giesl Peter
Published: June 2004

We consider a human elbow with a load and study the existence and stability of equilibrium positions without the use of reflexes. We observe that for each elbow angle there is a critical mass above which the equilibrium becomes unstable. We determine the optimal elbow angle, i.e., the angle such that the corresponding critical mass is as high as possible.
Stability Structure for Lattice Boltzmann Equations: Some Computational Results
Authors: Banda M.K. , Yong W.‐A. , Klar A.
Published: June 2004

The Lattice Boltzmann equations are usually constructed to satisfy physical requirements like Galilean invariance and isotropy as well as to possess a velocity‐independent pressure, no compressible effects, just to mention a few. In this paper, a stability criterion for such constructions is introduced and is used to derive a new relation of the parameters in a parametrized 2‐dimensional 9‐velocity model.
Analysis of lattice Boltzmann boundary conditions
Authors: Junk M. , Yang Z.
Published: June 2004

The correct implementation of Navier‐Stokes boundary conditions in the framework of lattice Boltzmann schemes is complicated by the non‐availability of analytical methods to assess the consistency of such discretizations. To close this gap, we propose a simple direct asymptotic analysis which is readily applicable to finite difference discretizations of initial boundary value problems in general and to lattice Boltzmann methods in particular. Results of the analysis applied to the classical lattice Boltzmann scheme with bounce back boundary condition are reported.
Mechanical Modelling of Drill‐Strings
Authors: Kreuzer E. , Struck H.
Published: June 2004

Vibrations in long torsional strings result in spatio‐temporal dynamics. These vibrations disturb the accuracy of the drilling process and may cause damage due to fatigue. The high costs of drillings are the main motivation for the suppression of vibrations of the drill–string. In this paper a model for the drill string is proposed. In order to describe the dynamics of the drill–string appropriately but as simple as possible the model has to comprise bending vibrations, self–excited torsional vibrations as well as the coupling between them. The aim of the model with only few degrees of freedom is the development of an optimal control technique for the active damping of drill–string vibrations. The string is modeled as a one–dimensional continuum. Two sets of variables are proposed for the formulation of kinematics: one is suitable for the description of the kinetic energy the other for the description of the elastic energy. Differential geometry yield equations which express one sets of variables in terms of the other. These equations can be linearised. In order to justify the linearisation, an analysis of the parameters is made. Since the Lagrangian can be written in a more compact form than the equations of motion, the Lagrangian is investigated: All variables are normalised and the order of magnitude of the terms are compared. The simplified Lagrangian yields the equations of motion which are solved approximately using Galerkin's method. Forces due to the interaction between the fluid and the structure are considered as well as those due to contact with the borehole.
Stability analysis of the servohydraulic equations with linear state feedback and harmonic reference signal
Authors: Manhartsgruber Bernhard
Published: June 2004

The servohydraulic equations describe the dynamic behaviour of a hydrostatic drive featuring a servo‐valve and a hydraulic cylinder. Under the assumptions of constant supply pressures, a rigid support of the cylinder, and a rigid mass attached to the piston, the evolution of cylinder pressures as well as piston position and velocity is governed by a 4th order non‐linear ordinary differential equation. The servo valve is assumed to be much faster than the dynamics of the mass‐cylinder system. Thus, the valve dynamics is neglected. Adding a feedback control law makes up the servohydraulic equations.

These equations are partially singularly perturbed. The perturbation parameter is associated with fluid compressibility and the reduced system corresponds to the case of an incompressible fluid. This paper deals with the stability analysis of periodic orbits arising in the case of harmonic reference position trajectories. Geometric singular perturbation theory is used to generate stability charts. Numerical computations verify the analytical results. For a given set of hydraulic system parameters, the stability of periodic orbits depends on controller gains as well as on the amplitude and frequency of the reference signal.
Moderately large flexural vibrations of sandwich plates with thick layers
Authors: Adam Christoph
Published: June 2004

In this paper moderately large amplitude vibrations of a polygonally shaped composite plate with thick layers are analyzed. Three homogeneous and isotropic layers with a common Poisson's ratio are perfectly bonded, and their arbitrary thickness and material properties are symmetrically disposed about the middle plane. Mindlin‐Reissner kinematic assumptions are implemented layerwise, and as such model both the global and local response. Geometric nonlinear effects arising from longitudinally constrained supports are taken into account by Berger's approximation of nonlinear strain‐displacement relations. The shear stress continuity across the interfaces is prescribed according to Hooke's law, and subsequently, a correspondence of this higher order problem to the simpler case of a homogenized shear‐deformable nonlinear plate with effective stiffness and hard hinged boundary conditions is found.
Length‐scale effect in dynamics of hexagonal lattice‐type plates
Authors: Cielecka Iwona , Jędrysiak Jarosław
Published: June 2004

In the contribution lattice‐type plates with hexagonal structure in plane 0x1x2 are analysed. The aim of the note is to apply a length‐scale model of lattice‐type periodic plates derived within the tolerance averaging method (developed for periodic composites and structures by Woźniak and Wierzbicki (2000)) to analyse vibrations of hexagonal plates. It will be shown that the derived model, taking into account the effect of the periodicity cell size on the overall plate behaviour, is represented by equations with constant coefficients in the form similar to equations for isotropic cases.
A note on the nonlinear modeling of piezoelectric rods
Authors: Gausmann Rainer , Seemann Wolfgang
Published: June 2004

Piezoceramic materials are usually calculated using linear constitutive equations if the exciting electric field is small. If the structure is excited near a resonance frequency the assumption of a linear material becomes invalid. Therefore nonlinear constitutive equations have to be used if the super harmonics in the measured velocity signals should be modeled. In this paper nonlinear constitutive equations are derived from the electric enthalpy density to describe the longitudinal oscillations of a piezoceramic rod. The kinetic energy considers the inertia effects in transversal direction so the model is not limited to the slender rod theory. With Hamilton's principle a variational principle is derived which is approximated using a Rayleigh Ritz ansatz with the first eigenfunction of the linearized system. The resulting nonlinear ODE is solved by application of the harmonic balance method. The amplitudes of displacement of the fundamental, the second and the third super harmonic oscillations are solved numerically. In a first step the results of the theoretical model are compared with measurements. The material parameters of the nonlinear constitutive equations are calculated using a parametric identification method. As a result it is shown that the theoretical model can describe the Duffing type nonlinearities found in measurements.
The Effect of Variable Eccentricity onto the Oscillations in a Coiling Process
Authors: Hammelmüller Franz , Holl Helmut J.
Published: June 2004

The mechanical model and the equations of motion of a rapid long‐term coiling process are presented. Additional effects are considered in the mechanical model in extension of the simple Laval‐rotor. Due to the coiled material the outer radius and the stiffness of the coiling drum varies with the rotation angle. The variable mass of the rotor has an important influence upon the oscillations of the rotor. Additionally, for the mechanical system under consideration, the resulting oscillations due to a variable eccentricity are analyzed. For the solution of the dynamic system an extended Newmark‐method is applied with a time‐step, which guarantees a converged solution. Numerical studies are performed for various parameters in order to highlight the influence of variable mass and variable eccentricity.
On the use of the Subspace Identification Method to identify Mechanical System Properties
Authors: Kompalka Andreas , Reese Stefanie
Published: June 2004

This contribution gives an overview about the present state of our research in the project B4 in the Collaborative Research Center 398 at the Ruhr University Bochum. The subject of the research topic is the diagnosis and localisation of discrete damage by vibration measurement with the aim of lifetime estimation. First of all, we discuss the verification of eigensystem realization algorithms for system identification. In the second part, a method for finite element model updating is investigated in view of its application for damage localization. A contribution of both methods is validated by means of a numerical example.
Reibleistendämpfung in Leichtbaustrukturen
Authors: Kröger Matthias , Reckmann Hanno , Popp Karl , Romberg Oliver
Published: June 2004

Die Erhöhung der Dämpfung in Leichtbaustrukturen ist immer dann sinnvoll, wenn die dynamischen Beanspruchungen durch Schwingungen dominant sind. Dann kann durch Reibleistendämpfer die Schwingungsamplitude und dadurch die Gesamtmasse reduziert werden. Die analytische Vorauslegung von Reibleisten wird an einem Seitenleitwerk aufgezeigt. Die berechneten und optimierten Dämpfungsgrade lassen sich durch experimentellen Untersuchungen bestätigen. Insgesamt zeigte sich ein großes Potential für den Einsatz von Reibleisten zur Dämpfungserhöhung.
Flutter instability of long‐span suspension bridges: a simplified critical wind speed evaluation in closed form
Authors: Maceri Franco , Vairo Giuseppe
Published: June 2004

A simplified approach able to determine in closed‐form the critical speed of the wind flow acting on long‐span suspension bridges is presented. Both flutter (single d.o.f. or binary) and torsional divergence instabilities are investigated.
Investigation of Parametric Resonance in Tuned Liquid Column Dampers
Authors: Reiterer Michael , Hochrainer Markus
Published: June 2004

Tuned liquid column dampers (TLCDs) are innovative vibration absorbing devices in the low frequency range, which have been studied extensively in the last decade. Most research work focuses on the suppression of horizontal motions of structures, but there is still a demand to investigate the influence of vertical motions on the damping behavior of TLCD, especially if the absorber is attached to earthquake excited buildings or long span bridges. When considering vertical motions the TLCD dynamics becomes nonlinear and quite sensitive to parametric resonance. Consequently an unstable system might be obtained, which is dangerous for the main structure. Hence, a small‐scale model of a TLCD under both, horizontal and vertical excitation has been developed and analyzed numerically and experimentally. For this sake, a small‐scale testing facility has been constructed to perform these experimental investigations. Samples of free and electro‐dynamically forced vibration experiments with different TLCD configurations and excitation scheme has been performed. The experimental results turned out in good agreement with the theoretical predictions of the computer model and both, theoretical and experimental studies indicate that the vertical motion of a structure should be considered carefully since in case of parametric resonance it might dominate the overall dynamic behavior of TLCDs.