bluuebunny/crossref_metadata_2025 huggingface dataset:
A new Bayesian method to forecast and fine tune individual hemodialysis dose
Authors: Pfister M , Uehlinger D E , Hung A M , Schaedeli F , Sheiner L B
Published: July 2004

Background:  The most commonly used formulas for hemodialysis dose are based on single‐pool urea kinetics; i.e., they consider the body as a single compartment and use an ad hoc adjustment for postdialysis urea rebound. We present a new urea kinetic modeling approach, individualized Bayesian urea kinetic modeling (IBKM), which incorporates prior knowledge. This method uses measurements made during previous treatments to forecast a patient's postdialysis urea rebound and clearance and provides a choice of possible dialysis parameters to achieve a desired clearance goal.

Methods:  We used data from 18 patients (a total of 38 hemodialysis sessions) to build the model. All patients had been on thrice‐weekly hemodialysis for at least 1 year before enrollment, and their dialysis prescription remained unchanged during the study period. Recorded variables included blood urea nitrogen (BUN) measurements and dialysis prescription parameters (dialyzer size, KoA, treatment time, blood and dialysis flow). The population distribution of urea kinetic parameters—derived from the 18 patients' data—and individual urea kinetic data (i.e., pre‐ and postdialysis BUN) are used in the IBKM method to make individual predictions.

Results:  Estimates (mean±SE) of population urea kinetic parameters are generation rate 0.17±0.01 mmol/min, clearance between extracellular and intracellular compartments 646±60 mL/min, and total volume of distribution 31.5±1.5 L, of which the extracellular volume is 36±4%. The effective dialysis clearance is estimated to be 9.0±1.7%, less than the expected dialyzer clearance. IBKM predictions of postdialysis equilibrated BUN concentrations are accurate: a root mean squared error of 3.4% of the “postrebound” BUN concentration at 30 min, a value in the range of urea measurement error itself.

Conclusions:  IBKM can estimate not only the urea kinetics of an actual hemodialysis, but it can also predict a patient's target hemodialysis dose for any desired, flexible hemodialysis treatment. The method should prove useful for bedside monitoring, forecasting, and fine tuning of hemodialysis dose.
Coronary and aortic calcifications in patients new to dialysis
Authors: Spiegel David M , Raggi Paolo , Mehta Ravindra , Lindberg Jill S , Chonchol Michel , Ehrlich James , James George , Chertow Glenn M , Block Geoffrey A
Published: July 2004

Background:  Vascular calcification has been associated with all cause and cardiovascular mortality in patients with end‐stage kidney disease (ESRD). Whether vascular calcification is present in persons with advanced chronic kidney disease starting dialysis or develops in patients on dialysis is unknown. The purpose of this study was to examine the prevalence of vascular and coronary calcification in patients new to hemodialysis.

Methods:  A total of 129 subjects new to dialysis were evaluated using electron beam computed tomography. The primary outcome was the presence and extent of coronary artery, aortic, and valvular calcification.

Results:  Forty‐three percent of subjects had no significant coronary artery calcification (total score ≤ 30) and 27% had no detectable aortic calcification. Thirty‐four percent had coronary artery scores that placed them above the 90th percentile for age and sex. Coronary artery calcification was significantly associated with a history of coronary artery disease and atherosclerotic vascular disease (ASVD) whereas aortic calcification was significantly associated with ASVD. Age (p < 0.0001), pulse pressure (p = 0.004), diabetes mellitus (p = 0.009), and a history of smoking (p = 0.026) were independently associated with the extent of coronary artery calcification. Age (p < 0.0001) and pulse pressure (p = 0.0003) were independently associated with the extent of aortic calcification.

Conclusions:  A large fraction of patients new to hemodialysis had no evidence of coronary artery or aortic calcification. Coupled with the extensive vascular calcification reported by others in prevalent dialysis patients these findings suggest that dialysis‐specific factors contribute to calcific vascular disease in ESRD.
Prevention of hemodialysis‐related muscle cramps by intradialytic use of sequential compression devices: A report of four cases
Authors: Ahsan Muhammad , Gupta Mini , Omar Irfan , Frinak Stanley , Gendjar Suzette , Osman‐Malik Yayha , Yee Jerry
Published: July 2004

Background:  Hemodialysis (HD)‐related lower extremity (LE) muscle cramps are a common cause of morbidity in end‐stage renal disease patients on maintenance HD. Numerous pharmacologic and physical measures have been tried with variable success rates.

Methods:  Sequential compression devices (SCD) improve venous return (VR) and are commonly used to prevent LE deep venous thrombosis in hospitals. We hypothesized that LE cramps are triggered by stagnant venous flow during HD and are preventable by improving VR. We prospectively studied four adult patients (mean age 61 ± 14 years) on thrice‐weekly HD who experienced two or more episodes of LE cramping weekly in the month before the study. SCD were applied before each HD on both legs and compressions were intermittently applied at 40 mmHg during treatment.

Results:  All four patients reported complete resolution of cramping during the study period that lasted 1 month or 12 consecutive dialysis treatments.

Conclusion:  Application of SCD to LE may prevent the generation of LE HD‐related cramping in a select group of patients. Larger, controlled studies are needed to establish the utility of this noninvasive alternative for the prevention of LE HD‐related cramps.
On the origin of the chordate central nervous system: expression of onecut in the sea urchin embryo
Authors: Poustka Albert J. , Kühn Alexander , Radosavljevic Vesna , Wellenreuther Ruth , Lehrach Hans , Panopoulou Georgia
Published: July 2004

Summary
We identified a transcription factor of the onecut class in the sea urchin Strongylocentrotus purpuratus that represents an ortholog of the mammalian gene HNF6, the founding member of the onecut class of proteins. The isolated sea urchin gene, named SpOnecut, encodes a protein of 483 amino acids with one cut domain and a homeodomain. Phylogenetic analysis clearly places the sea urchin gene into this family, most closely related to the ascidian onecut gene HNF‐6. Nevertheless, phylogenetic analysis reveals a difficult phylogeny indicating that certain members of the family evolve more rapidly than others and also that the cut domain and homeodomain evolve at a different pace. In fly, worm, ascidian, and teleost fish, the onecut genes isolated so far are exclusively expressed in cells of the central nervous system (CNS), whereas in mammals the two copies of the gene have acquired additional functions in liver and pancreas development. In the sea urchin embryo, expression is first detected in the emerging ciliary band at the late blastula stage. During the gastrula stage, expression is limited to the ciliary band. In the early pluteus stage, SpOnecut is expressed at the apical organ and the elongating arms but continues most prominently in the ciliary band. This is the first gene known that exclusively marks the ciliary band and therein the apical organ in a pluteus larva, whereas chordate orthologs execute essential functions in dorsal CNS development. The significance of this finding for the hypothesis that the ciliary bands and apical organs of the hypothetical “dipleurula”‐like chordate ancestor and the chordate/vertebrate CNS are of common origin is discussed.
Evidence from Hox genes that bryozoans are lophotrochozoans
Authors: Passamaneck Yale J. , Halanych Kenneth M.
Published: July 2004

Summary
Bryozoans, or moss animals, are small colonial organisms that possess a suspension‐feeding apparatus called a lophophore. Traditionally, this “phylum” has been grouped with brachiopods and phoronids because of the feeding structure. Available molecular and morphological data refute this notion of a monophyletic “Lophophorata.” Alternative hypotheses place bryozoans either at the base of the Lophotrochozoa or basal to the Lophotrochozoa/Ecdysozoa split. Surprisingly, the only molecular data bearing on this issue are from the 18S nuclear ribosomal gene. Here we report the results of a Hox gene survey using degenerate polymerase chain reaction primers in a gymnolaemate bryozoan, Bugula turrita. Putative orthologs to both the Post2 and the Lox5 genes were found, suggesting that bryozoans are not a basal protostome group but closely allied to other lophotrochozoan taxa. We also found the first definitive evidence of two Deformed/Hox4 class genes in a nonvertebrate animal.
Rapid evaluation of risk of white particulate matter in blood components by a statewide survey of transfusion reactions
Authors: Iwamoto M. , Curns A.T. , Blake P.A. , Jernigan D.B. , Holman R.C. , Lance‐Parker S.E. , Chamberland M.E. , Kuehnert M.J.
Published: July 2004

BACKGROUND:  In January 2003, white particulate matter (WPM) was detected in blood components. Because the composition and cause of WPM was not understood at that time, there was uncertainty about whether WPM could endanger patient safety. To investigate possible adverse patient events associated with WPM, transfusion reaction rates were examined.

STUDY DESIGN AND METHODS:  A questionnaire was distributed to Georgia medical centers. Data collected included the number of components transfused and reported adverse reactions by component type from January 2002 through January 2003, and date, reaction type, and blood supplier for events in January 2003.

RESULTS:  Of 124 transfusion services contacted, 108 (87%) responded. During the survey period, there were 1213 reported transfusion reactions and 528,412 units transfused, or 2.3 reactions per 1000 units transfused; for RBCs, 2.4 (range, 1.8‐3.1); plasma, 1.5 (range, 0.6‐3.5); and PLTs, 3.4 (2.1‐5.4) per 1000 units. Transfusion reaction rates by component for January 2003 did not differ significantly from the rate for January 2002 or for the calendar year. The 86 reported reactions that occurred in January 2003 were attributed to bacterial contamination (n = 2, 2.3%), other febrile nonhemolytic (n = 49, 57.0%), allergic (n = 14, 16.3%), and “other” reactions (n = 21, 24.4%); the proportions of reaction types did not differ significantly during the month.

CONCLUSION:  No overall changes in reported adverse reaction rates occurred over the survey period or in the proportion of reaction types during January 2003 when WPM was detected. Statewide surveillance of transfusion reactions could be useful to evaluate potential threats to blood safety.
Different susceptibility of B19 virus and mice minute virus to low pH treatment
Authors: Boschetti Nicola , Niederhauser Isabel , Kempf Christoph , Stühler Albert , Löwer Johannes , Blümel Johannes
Published: July 2004

BACKGROUND:  Parvoviridae are small nonenveloped viruses that are known to be highly resistant to physico‐chemical treatments. Because low pH is frequently applied to process intermediates or final products, the impact of such conditions on the human erythrovirus B19 (B19V) and the mouse parvovirus (mice minute virus, MMV) was assessed, which is often used as a model for B19V. Owing to the lack of a suitable cultivation and/or detection system for B19V no such data exist so far.

STUDY DESIGN AND METHODS:  Virus inactivation was monitored by decrease of infectivity and loss of capsid integrity. Infectious B19V was quantified by dete‐ction of virus‐specific messenger RNA from Ku812Ep6 cells. To measure capsid integrity, endonucleases were added after exposure to low pH and the encapsidated (endonuclease‐protected) virus DNA was quantified by real‐time PCR.

RESULTS:  B19V was inactivated greater than 5 log after 2 hours at pH 4, whereas MMV was resistant over 9 hours. Infectivity data strongly correlated with data obtained by the endonuclease assay. Capsid disintegra‐tion was observed in immunoglobulin G as well as in different albumin solutions. Temperature and pH showed concerted impact on B19V capsid disintegration.

CONCLUSION:  Our data show that B19V is much more vulnerable toward low pH conditions than MMV. Together with the previously reported susceptibility of B19V toward wet heat conditions, low pH is the second treatment where erythrovirus B19V is less resistant than viruses from the parvovirus genus.
A new hybrid RHCE gene (CeNR) is responsible for expression of a novel antigen
Authors: Westhoff Connie M. , Storry Jill R. , Walker Phyllis , Lomas‐Francis Christine , Reid Marion E.
Published: July 2004

BACKGROUND:  The red blood cells (RBCs) of a patient, known to have the probable DCW(e)/D‐‐ phenotype, typed as DW– and Rh32– but were unexpectedly agglutinated by an anti‐DW/Rh32 serum. The reactivity suggested that the RBCs carried a novel antigen and that the molecular background of this DCW(e)/D‐‐ phenotype might be different from those reported. The purpose of this study was to determine the molecular basis of the Rh phenotype.

STUDY DESIGN AND METHODS: Samples were obtained for family studies. Standard hemagglutination methods were used. RH mRNA transcripts were isolated by reverse transcription‐polymerase chain reaction and sequenced.

RESULTS:  Sequence analysis revealed that the probond had three different RH transcripts: a normal RHD and two different hybrid transcripts from the RHCE locus, a RHCE‐D hybrid with exon 1 from RHCE associated with the D‐‐ haplotype, and a new RHCE‐D hybrid. In this new hybrid, exons 1 to 5 are RHCe‐specific and exons 6 to 10 correspond to RHD. The CW antigen is also encoded by this hybrid gene. Family studies confirmed that the new RHCE‐D hybrid is linked in cis to conventional RHD.

CONCLUSION:  A new RHCE‐D structure is associated with altered expression of C and e antigens in this family and the generation of a novel low‐prevalence antigen (CENR).
Capillary blood cell velocity in periulcerous regions of the lower leg measured by laser Doppler anemometry
Authors: Stücker Markus , Huntermann Christina , Bechara Falk Georges , Hoffmann Klaus , Altmeyer Peter
Published: July 2004

Background: The capillary blood flow of the nailfold can be measured by means of modern non‐invasive techniques like the videocapillary microscope in vivo. To quantify the capillary blood cell velocity, apart from the nailfold capillaries, we used a new technique, the so‐called laser Doppler anemometry (LDA).

Objective: The present study investigated how far laser Doppler fluxmetry (LDF), transcutaneous partial pressure of oxygen (tcpO2), and LDA are capable of quantifying differences of cutaneous microcirculation between patients with leg ulcera and a healthy control group. The effects of intravenous prostaglandin E1 and pentoxifylline were also investigated.

Patients and methods: Ten patients with venous leg ulcers and 10 patients with mixed venous/arterial ulcers were investigated with LDF, tcpO2, and LDA before and after injection of prostaglandin E1 and pentoxifylline. We measured the resting capillary blood cell velocity (rCBV), the maximum hyperemia, and the time to peak capillary blood cell velocity (tpCBV) during hyperemia after 4 min of suprasystolic occlusion and compared them with the results of a contol group of 20 patients.

Results: Laser Doppler flow was increased in all patients during resting period, whereas the tcpO2 was significantly decreased. LDF did not show an extension of tpCBV during reactive hyperemia after suprasystolic occlusion compared to the control group (73.6±31.1 vs. 164.1±52.5 s, P=0.003). TcpO2 revealed significantly dereased tpCBV in patients with venous and mixed venous/arterial ulcers (90.1±61.7 vs. 162.7±65.5 s, P≤0.0001). LDA showed no significant differences between patients and control group (P>0.8). After application of prostaglandin E1, LDA revealed a significant increase of erythrocyte velocity (0.5±0.18 to 0.74±0.28 mm/s [P=0,01]), whereas pentoxifylline had no significant effect. Capillary density increased significantly after application of prostaglandin E1 (5,1±2.7/mm2 to 8.9±3/mm2 [P=0.001]) and pentoxifylline (5.3± 1.8/mm2 to 8±2.1/mm2 [P=0.006]).

Conclusion: The LDA is an important additional investigation tool for cutaneous microcirculation.
Clinically normal atopic skin vs. non‐atopic skin as seen through electrical impedance
Authors: Nicander Ingrid , Ollmar Stig
Published: July 2004

Background/aims: In an earlier study, we have shown that the electrical impedance (IMP) is dependent on the lipid content of the stratum corneum as studied by lipid extraction. Therefore, we now employ the IMP technique to compare the properties of clinically normal atopic skin with that of non‐atopic skin. We looked at the same time at concomitant alterations in transepidermal water loss (TEWL) and skin moisture results.

Methods: Twenty‐two healthy participants and 26 patients with atopic dermatitis were recruited. One test site on each volar forearm was used in the test procedure, of cyclohexane swabbing, skin stripping, and lipid extraction using a mixture of hexane:isopropanol. Responses were evaluated by measuring TEWL, skin moisture using electrical capacitance, and finally IMP spectroscopy in the frequency range 1 kHz to 1 MHz before the start of the study, after each step of the test procedure, and also during a 2 weeks recovery period.

Results: Only the IMP results showed significant changes between baseline values of clinically normal atopic skin and healthy skin. Furthermore, IMP and TEWL showed significantly larger reactivity for the atopic group after the skin stripping procedure, and IMP after lipid extraction as well.

Conclusion: Our results show that IMP is a useful method for detection of changes in the lipid content of the stratum corneum by discriminating healthy looking atopic skin from healthy control skin, and to detect changes in reactivity between the two groups.
In vivo morphological characterisation of skin by MRI micro‐imaging methods
Authors: Mirrashed Fakhereh , Sharp Jonathan C.
Published: July 2004

Background/purpose: Quantitative assessments in skin layers using images obtained with standard magnetic resonance imaging (MRI) sequences are limited, since the stratum corneum and dermis, the layers of most clinical interest, have low signal due to their short spin–spin relaxation, T2.

Methods: In the present work, different methods of MRI contrast, such as magnetisation transfer contrast (MTC), T1‐weighting (where T1 is spin–lattice relaxation time), T2*‐weighting (where T2* is the combination of T2 and magnetic field in‐homogeneity effect) and chemical shift, were used. These techniques were combined with high‐resolution MRI.

Results: We found that skin is a very MT active tissue, and MTC provides data enabling the evaluation of how the tissue in skin layers interacts with the interstitial fluids. Details obtained from high‐resolution high‐quality in vivo skin images with different contrast allowed for differentiation of skin layers, sub‐layers and excellent correlation of MR data with known histological features and water constituent of skin layers.

Conclusion: Combining MT and other MRI data employing other contrast mechanisms provides a superior non‐invasive in vivo technique for visualisation and also quantitative assessment of the constituents of the stratum corneum, epidermis, papillary dermis, reticular dermis and hypodermis as major structural layers of the skin. This type of study can be extended to cutaneous disease states or skin ageing, where defects in water mobility, concentration and/or macromolecular structural changes are expected.
Topical negative pressure therapy: mechanisms and indications
Authors: Banwell Paul E , Musgrave Melinda
Published: July 2004

Topical negative pressure (TNP) therapy has emerged as a high‐technology, microprocessor‐controlled physical wound‐healing modality. Complex effects at the wound–dressing interface following application of a controlled vacuum force have been documented. These include changes on a microscopic, molecular level and on a macroscopic, tissue level: interstitial fluid flow and exudate management, oedema reduction, effects on wound perfusion, protease profiles, growth factor and cytokine expression and cellular activity, all leading to enhanced granulation tissue formation and improved wound‐healing parameters. Primary indications for clinical use have been documented and include traumatic wounds, open abdominal wounds, infected sternotomy wounds, wound bed preparation, complex diabetic wounds and skin‐graft fixation. Whilst this therapy now forms an essential part of the wound healing armamentarium, extensive clinical trials are recommended to confirm efficacy and delineate its optimum use.
An unusual lesion on the chest wall
Authors: Pandey Manoj , Chandramohan K Nair , Mathew Anitha
Published: July 2004

Osteoradionecrosis is an exceptional complication after the treatment of breast carcinoma. We report here a 63‐year‐old woman who presented with osteoradionecrosis of the sternum 17 years after initial treatment for breast cancer. Difficulty in diagnosing the lesion and its management is discussed.
Water‐Soluble Polysaccharide from Eleutherococcus senticosus Stems Attenuates Fulminant Hepatic Failure Induced by D‐Galactosamine and Lipopolysaccharide in Mice
Authors: Park Eun‐Jeon , Nan Ji‐Xing , Zhao Yu‐Zhe , Lee Sung Hee , Kim Young Ho , Nam Jeong Bum , Lee Jung Joon , Sohn Dong Hwan
Published: July 2004

Abstract: The aim of this study was to investigate whether Eleutherococcus senticosus stems could attenuate D‐galactosamine/lipopolysaccharide‐induced fulminant hepatic failure in mice. E. senticosus, known as Siberian ginseng, is a popular folk medicine used as a tonic in Asia. Preparations of E. senticosus used in this study were as follows; (i) 70% ethanol extract (ii) water extract (iii) ethanol‐soluble part of the water extract (iv) polysaccharide obtained as an 80% ethanol insoluble of the water extract. Preparations were given by intraperitoneal (300 mg/kg and 50 mg/kg) or oral (300 mg/kg) injection at 12 hr and 1 hr before a D‐galactosamine/lipopolysaccharide injection. The intraperitoneal injection of water extract and polysaccharide significantly lowered serum levels of tumour necrosis factor‐α, aspartate transaminase and alanine transaminase, improved the histologic changes in liver, inhibited hepatocyte apoptosis confirmed by the terminal deoxynucleotidyl transferase‐mediated dUTP nick end‐labeling method and DNA fragmentation assay, and suppressed the lethality induced by D‐galactosamine/lipopolysaccharide. The oral administration of water extract and polysaccharide also reduced serum aspartate transaminase, alanine transaminase and tumour necrosis factor‐α levels. In contrast 70% ethanol extract and ethanol‐soluble part of the water extract had no protective effect when treated intraperitoneally or orally. These results indicate E. senticosus stems attenuate fulminant hepatic failure induced by D‐galactosamine/lipopolysaccharide in mice and the protective effect is due to water‐soluble polysaccharides in E. senticosus stems.
An observer study comparing spot imaging regions selected by radiologists and a computer for an automated stereo spot mammography technique
Authors: Goodsitt Mitchell M. , Chan Heang‐Ping , Lydick Justin T. , Gandra Chaitanya R. , Chen Nelson G. , Helvie Mark A. , Bailey Janet E. , Roubidoux Marilyn A. , Paramagul Chintana , Blane Caroline E. , Sahiner Berkman , Petrick Nicholas A.
Published: July 2004

We are developing an automated stereo spot mammography technique for improved imaging of suspicious dense regions within digital mammograms. The technique entails the acquisition of a full‐field digital mammogram, automated detection of a suspicious dense region within that mammogram by a computer aided detection (CAD) program, and acquisition of a stereo pair of images with automated collimation to the suspicious region. The latter stereo spot image is obtained within seconds of the original full‐field mammogram, without releasing the compression paddle. The spot image is viewed on a stereo video display. A critical element of this technique is the automated detection of suspicious regions for spot imaging. We performed an observer study to compare the suspicious regions selected by radiologists with those selected by a CAD program developed at the University of Michigan. True regions of interest (TROIs) were separately determined by one of the radiologists who reviewed the original mammograms, biopsy images, and histology results. We compared the radiologist and computer‐selected regions of interest (ROIs) to the TROIs. Both the radiologists and the computer were allowed to select up to 3 regions in each of 200 images (mixture of 100 CC and 100 MLO views). We computed overlap indices (the overlap index is defined as the ratio of the area of intersection to the area of interest) to quantify the agreement between the selected regions in each image. The averages of the largest overlap indices per image for the 5 radiologist‐to‐computer comparisons were directly related to the average number of regions per image traced by the radiologists (about 50% for 1 region/image, 84% for 2 regions/image and 96% for 3 regions/image). The average of the overlap indices with all of the TROIs was 73% for CAD and for the radiologists. This study indicates that the CAD determined ROIs could potentially be useful for a screening technique that includes stereo spot mammography imaging.
Role of multimodality imaging in radiotherapy planning
Authors: Lee Young K.
Published: July 2004

Accurate tumor delineation is crucial to achieve successful radiotherapy (RT). While CTs are clinically used to plan 3D–RT, multimodality imaging (MMI) promises to aid accurate delineation of the tumor. This thesis examined delineated MMI volumes and studied their role in RT planning. A prostate modeling study evaluated the dose reductions in conformal and intensity‐modulated radiotherapy (CRT and IMRT) due to interfractional gross tumor volume (GTV) motion and variability in delineation. In both CRT and IMRT, a 10 mm margin was adequate to account for interfractional GTV movement. However, 10 mm (CRT) and 5 mm (IMRT) GTV misdelineation produced unacceptable dose distributions. IMRT plans were more affected by delineation errors when compared to CRT plans due to their steep dose gradients. Methods were developed to use MRI only in RT planning. Water and bone electron density values were assigned to the image and a low‐distortion MR‐sequence was used. MR‐delineated prostate volumes were in general smaller than those on CT by 10%. Patient data were separated into those that were affected by organ motion from those that were not. An independent‐organ registration technique was developed to relate CT‐ and MR‐delineated volumes that were affected by organ motion between the scans. The dosimetric study showed that unacceptable CRT was planned using planning target volume delineated using CT when volumes were assumed to be true. However, the dosimetric benefit was small as a 1–2 mm marginal increase on would deliver adequate dose to both PTVs and insignificant dose reductions were observed in rectum and bladder when plans were compared to plans. The dosimetric effect of in neuroblastoma CRT and IMRT was studied. Reduction in tumor control probability due to incorrectly delineated neuroblastoma was observed and a new treatment was planned using with acceptable doses to OARs the organs‐at‐risk. IMRT delivered more conformal dose distributions to complex‐shaped PTVs compared to CRT. Methods required to add currently acquired diagnostic to thoracic lymphoma RT planning were developed. The addition confirmed the inferior disease extension in 60% of the cases studied and in 20% of cases, presented a large inferior difference. The addition of FDG–PET would affect the field sizes and the extension of lead blocking. A theoretical CRT study showed that greater than 50% decrease in lung dose was achievable with when compared to the original plan. This thesis highlighted not only the importance of using MMI in RT planning but developed methods to cope with the additional information. Though not all the imaging modalities added a significant dosimetric benefit, they added new information regarding GTV determination and decreased the subjectivity of GTV delineation with minimal technical difficulty, which will benefit current RT planning.
Respiratory motion of the heart: Implications for magnetic resonance coronary angiography
Authors: Shechter Guy
Published: July 2004

Magnetic resonance (MR) coronary imaging is susceptible to artifacts caused by motion of the heart. The purpose of this thesis was to study the respiratory motion of the coronary arteries and to use the results to develop strategies for improved MR imaging. The first section of the thesis describes a MR motion correction technique for objects undergoing a 3D affine transformation. The remainder of the thesis focuses on measuring the respiratory motion of the heart from free breathing x‐ray angiograms. Stereo reconstruction methods are used to generate 3D models of the arteries from biplane angiograms. A method for tracking the motion of the arteries in a sequence of biplane images is presented next. The algorithm uses 3D regularizing constraints on the length changes of the arteries and on the spatial regularity of their motion. The algorithm was validated using a deforming vascular phantom. RMS 3D distance errors were measured between centerline models tracked in the x‐ray images and gold‐standard models derived from a gated 3D MR acquisition. The mean error was for four different orientations of the x‐ray system. The motion field recovered from free breathing angiograms is a combination of the cardiac contraction and respiratory motion of the heart. A cardiac respiratory parametric model is formulated to decompose the field into independent cardiac and respiratory components. Results are presented for ten patients imaged during spontaneous tidal breathing. For all patients, the heart translated caudally (mean, and rotated in a cranio‐dorsal direction (mean, during inspiration. In eight patients, the heart also translated anteriorly (mean, and rotated in a caudo‐dextral direction (mean, . Anatomic landmarks were used to compare results across patients. Three dimensional displacements and velocities were compared, and quiescent periods in the respiratory and cardiac cycles were measured. Finally, respiratory motion was analyzed using three linear motion models that correspond to available MR motion correction techniques: translation, rigid body, and affine. Calculations indicate that a two‐to‐four‐fold increase in scan efficiency is attainable, resulting in reduced scan times while maintaining image quality.
Evaluation of the new cesium‐131 seed for use in low‐energy x‐ray brachytherapy
Authors: Murphy Mark K. , Piper R. Kim , Greenwood Lawrence R. , Mitch Michael G. , Lamperti Paul J. , Seltzer Stephen M. , Bales Matt J. , Phillips Mark H.
Published: July 2004

Characterization measurements and calculations were performed on a new medical seed developed by IsoRay Inc. in Richland, Washington, that utilizes the short‐lived isotope This model has recently received FDA 510(k) clearance. The objective of this work was to characterize the dosimetric properties of the new seed according to the AAPM Task Group 43 recommendations. Cesium‐131 is a low‐energy x‐ray emitter, with the most prominent peaks in the 29 keV to 34 keV region. The intended application is brachytherapy for treating cancers in prostate, breast, head and neck, lung, and pancreas. The evaluations performed included air‐kerma strength, radial dose function, anisotropy in phantom, half‐life, energy spectra, and internal activity. The results indicate the CS‐1 seeds have a dose‐rate constant of in water, dose penetration characteristics similar to and anisotropy function values on the order of 0.71 at short distances and small angles, and an average anisotropy factor of 0.964. The overall dosimetric characteristics are similar to and seeds with the exception of half‐life, which is 9.7 days, as compared to 17 days for and 60 days for The shorter half‐life may offer significant advantages in biological effectiveness.
The relationship between professional operatic soprano voice and high range spectral energy
Authors: Barnes Jennifer J. , Davis Pamela , Oates Jennifer , Chapman Janice
Published: July 2004

Operatic sopranos need to be audible over an orchestra yet they are not considered to possess a singer’s formant. As in other voice types, some singers are more successful than others at being heard and so this work investigated the frequency range of the singer’s formant between 2000 and 4000 Hz to consider the question of extra energy in this range. Such energy would give an advantage over an orchestra, so the aims were to ascertain what levels of excess energy there might be and look at any relationship between extra energy levels and performance level. The voices of six operatic sopranos (national and international standard) were recorded performing vowel and song tasks and subsequently analyzed acoustically. Measures taken from vowel data were compared with song task data to assess the consistency of the approaches. Comparisons were also made with regard to two conditions of intended projection (maximal and comfortable), two song tasks (anthem and aria), two recording environments (studio and anechoic room), and between subjects. Ranking the singers from highest energy result to lowest showed the consistency of the results from both vowel and song methods and correlated reasonably well with the performance level of the subjects. The use of formant tuning is considered and examined.
The corono-apically varying ultrasonic velocity in human hard dental tissues
Authors: John Christoph
Published: July 2004

The speed of ultrasound at 20 MHz is measured for hard dental tissues inside human teeth. This includes the cementum, for which no data are available. The spatial distribution, extrema, and means of the longitudinal ultrasound velocity (LUV) are determined with an emphasis on the apical thirds and an extended spectrum. Tissue areas are investigated by optical means and by acoustical scanning, in order to compare apical regions-of-interest with the complete mineralized wet porous tissue that lies beneath the enamel cap. The maximal LUV in a single dentin specimen varies from 3903 m/s to 4226 m/s. The dentin’s frequency distribution of LUV at 20 °C exhibits a predominant peak feature comprising several Voigt functions. Introducing standardized relative tooth width portions, the corono-apical decrease in LUV of 21 specimens is approximated by LUV=4224−(257 *  ln(y)) along reduced distances in dentin. Abnormal teeth require a higher resolution and an approximate equation of the form LUV=(∑(ai * yi))/(1+∑(bi+1 * y(i+1))). It can be used each time the corono-apical variation has to be quantified in each of the three tissues. Ten coefficients are numerically exemplified. An error evaluation is performed, which denotes errors of 0.2%±1.3% (enamel), −0.1%±1.6% (cementum), and acceptable residual errors for dentin.
On the feasibility of elastic wave visualization within polymeric solids using magnetic resonance elastography
Authors: Romano Anthony J. , Bucaro Joseph A. , Houston Brian H. , Kugel Jennifer L. , Rossman Phillip J. , Grimm Roger C. , Ehman Richard L.
Published: July 2004

In this paper, the feasibility of extending previously described magnetic resonance elastography (MRE) dynamic displacement (and associated elasticity) measurement techniques, currently used successfully in tissue, to solid materials which have much higher shear rigidity and much lower nuclear spin densities, is considered. Based on these considerations, the MRE technique is modified in a straightforward manner and used to directly visualize shear wave displacements within two polymeric materials, one of which is relatively stiff.
A biophysical model of an inner hair cell
Authors: Zeddies David G. , Siegel Jonathan H.
Published: July 2004

Whole-cell patch-clamp recordings on isolated inner hair cells (IHCs) of guinea pig cochleae have revealed the presence of voltage-gated potassium channels. A biophysical model of an IHC is presented that indicates activation of slow voltage-gated potassium channels may lead to receptor potentials whose dc component decreases during the stimulus, and membrane potential hyperpolarizes when the stimulus is turned off. Both the decreasing dc and the hyperpolarization are, respectively, consistent with rapid adaptation and suppression of spontaneous rate in the auditory nerve. Receptor potentials recorded in vivo do not show these features, and when a nonspecific leak is included in the model to simulate microelectrode impalement, the model’s receptor potentials become similar to those in vivo. The nonspecific leak creates an electrical shunt that masks slow channel activity and allows the cell to depolarize. Both the decreasing dc and the hyperpolarization are sensitive to the resting potential. Because the reported resting potentials in vivo and in vitro differ greatly, the model is used to investigate homeostatic mechanisms responsible for the resting potential. It is found that the voltage-gated potassium channels have the greatest influence on the resting potential, but that the standing transducer current may be sufficient to eliminate the decreasing dc and after-stimulus hyperpolarization.
Noise annoyance from stationary sources: Relationships with exposure metric day–evening–night level (DENL) and their confidence intervals
Authors: Miedema Henk M. E. , Vos Henk
Published: July 2004

Relationships between exposure to noise [metric: day–evening–night levels (DENL)] from stationary sources (shunting yards, a seasonal industry, and other industries) and annoyance are presented. Curves are presented for expected annoyance score, the percentage “highly annoyed” (%HA, cutoff at 72 on a scale from 0 to 100), the percentage “annoyed” (%A, cutoff at 50 on a scale from 0 to 100), and the percentage “(at least) a little annoyed” (%LA, cutoff at 28 on a scale from 0 to 100). The estimates of the parameters of the relations are based on the data from a field study (N=1875) at 11 locations (2 shunting yards, 1 seasonal industry, 8 other industries) in the Netherlands. With the same (yearly) DENL, the seasonal industry causes less annoyance than the other industries, while the other industries cause less annoyance than the shunting yards. It appears that annoyance caused by vibrations from shunting yards and annoyance caused by noise from through trains are (partly) responsible for the relatively high annoyance from shunting yards. The relatively low annoyance from the seasonal industry presumably is related to the presence of a relatively quiet period. Results for the two shunting yards and the seasonal industry are based on fewer data than the other industrial sources, and are indicative. The same patterns of influence of age and noise sensitivity that are generally found are also found in this study. For comparison, results regarding transportation sources are also given, including previously unpublished results for expected annoyance.
Regularization method for the application of K-space data extrapolation to near-field acoustical holography
Authors: Saijyou Kenji
Published: July 2004

A regularization method for applying the K-space data extrapolation method to near-field acoustical holography (NAH) is proposed. The influence of the finiteness of measurement aperture is a serious impediment to the NAH reconstruction of structural vibration when the size of the measurement aperture is smaller than that of the structure. The K-space data extrapolation method has been proposed to reduce the influence of this finiteness. An appropriate regularization method is necessary to apply the K-space data extrapolation method if the measured pressure is contaminated by noise. Some regularization methods for NAH have been proposed. However, it is difficult to determine an appropriate K-space filter if the finiteness of the measurement aperture becomes an issue. An estimation method of appropriate regularization filter for applying the K-space data extrapolation method is proposed to solve this difficulty. The effectiveness of this method is demonstrated by simulations. The simulation results confirm that (1) an appropriate regularization filter may be constructed to realize spatial wave number characteristics similar to that of ideal full aperture and (2) the reconstruction error is sufficiently suppressed by the proposed method.
Specification of cross-modal source information in isolated kinematic displays of speech
Authors: Lachs Lorin , Pisoni David B.
Published: July 2004

Information about the acoustic properties of a talker’s voice is available in optical displays of speech, and vice versa, as evidenced by perceivers’ ability to match faces and voices based on vocal identity. The present investigation used point-light displays (PLDs) of visual speech and sinewave replicas of auditory speech in a cross-modal matching task to assess perceivers’ ability to match faces and voices under conditions when only isolated kinematic information about vocal tract articulation was available. These stimuli were also used in a word recognition experiment under auditory-alone and audiovisual conditions. The results showed that isolated kinematic displays provide enough information to match the source of an utterance across sensory modalities. Furthermore, isolated kinematic displays can be integrated to yield better word recognition performance under audiovisual conditions than under auditory-alone conditions. The results are discussed in terms of their implications for describing the nature of speech information and current theories of speech perception and spoken word recognition.
Acoustic nonlinearity of liquid containing encapsulated microbubbles
Authors: Ma Jian , Yu Jinfei , Fan Zheng , Zhu Zhemin , Gong Xiufen , Du Gonghuan
Published: July 2004

Recently, a high value nonlinear parameter of liquid containing contrast agents (encapsulated microbubbles) has been reported by some measurements, however an effective way to study it theoretically has not been found so far. In this paper, an approach, based on the concept of the equivalent nonlinear parameter is presented to estimate the nonlinear property of such media. The liquid containing encapsulated microbubbles is treated as a homogenous liquid with a equivalent nonlinear parameter. An experimental approximate linear relationship for attenuation and nonlinear parameter with bubble volume is confirmed from our calculation. It is also found that when a microbubble is encapsulated by a shell, the nonlinear oscillation of the bubble is restrained; the second and higher harmonics are generated not so effectively compared to a free bubble. Naturally this causes the nonlinear parameter of such a liquid to decrease greatly. Favorable agreement between the theory and Wu et al.’s experiments shows this approach could effectively estimate the nonlinearity of encapsulated bubbly liquid. Finally, some applicable limitations for this approach are also mentioned.
Numerical simulation of two-dimensional nonlinear standing acoustic waves
Authors: Vanhille Christian , Campos-Pozuelo Cleofé
Published: July 2004

In this paper the behavior of strongly nonlinear waves in two-dimensional resonators filled with thermoviscous fluid is studied. For this purpose a set of differential equations, written in Lagrangian coordinates, is proposed and a time-domain numerical scheme is developed for solving them. Full nonlinear equations are derived from the conservation laws and state equation by assuming an irrotational fluid. Auxiliary conditions are written by considering a rigid-walled cavity, excitation at some points of the boundary, and rest at the outset. Finite differences are applied in the space and time domains, and lead to an implicit scheme. The numerical model solves the problem in terms of displacement vector field. The pressure field is then obtained from the displacement values. The algorithm allows us to analyze the evolution of the behavior of complex standing waves. The nonlinear characteristics of standing waves, well known in one-dimensional chambers, are now apparent in two-dimensional resonators by means of this new computational model. Some numerical experiments are carried out, a validation of the model is achieved, and results are given at a complex mode for which plane wave approximation is not appropriate. Several aspects of the nonlinear pressure field inside two-dimensional resonators are presented, such as harmonic distortion and nonlinear attenuation effects. In particular the quasi-standing character of such waves is detected and described. The effect of redistribution of rms pressure inside a two-dimensional cavity is commented.
Sounds produced by Norwegian killer whales, Orcinus orca, during capture
Authors: Van Parijs Sofie M. , Leyssen Teo , Similä Tiu
Published: July 2004

To date very little is still known about the acoustic behavior of Norwegian killer whales, in particular that of individual whales. In this study a unique opportunity was presented to document the sounds produced by five captured killer whales in the Vestfjord area, northern Norway. Individuals produced 14 discrete and 7 compound calls. Two call types were used both by individuals 16178 and 23365 suggesting that they may belong to the same pod. Comparisons with calls documented in Strager (1993) showed that none of the call types used by the captured individuals were present. The lack of these calls in the available literature suggests that call variability within individuals is likely to be large. This short note adds to our knowledge of the vocal repertoire of this population and demonstrates the need for further studies to provide behavioural context to these sounds.
Thickening effect in soluble hydrogen-bonding interpolymer complexes. Influence of pH and molecular parameters
Authors: Bossard F. , Sotiropoulou M. , Staikos G.
Published: July 2004

Linear and nonlinear viscoelastic properties of poly(acrylic acid) (PAA) and poly(acrylic acid-co-2-acrylamido-2-methylpropane sulfonic acid)-graft-poly(N,N-dimethylacrylamide) (P(AA-co-AMPSA)-g-PDMAM) mixtures have been investigated as a function of pH, the PDMAM content of the graft copolymer and the molecular weight of PAA. At pH < 3.75, strong hydrogen-bonding interpolymer complexation between PAA and PDMAM side chains in semidilute solution leads to the formation of a transient network, as the considerable increase in viscosity indicates. The sol/gel transition observed at pH=2.0 by increasing the graft copolymer composition in PDMAM is explained by a substantial increase in the number of the junctions (stickers) resulting from the PDMAAM/PAA hydrogen bonding complexation. Moreover, the thickening effect observed is further strengthened by increasing the molecular weight of PAA, due to the interconnection of more copolymer chains.
Linking Albinism and Immunity: The Secrets of Secretory Lysosomes
Authors: Stinchcombe Jane , Bossi Giovanna , Griffiths Gillian M.
Published: July 2004

Lysosomes are membrane-bound organelles that are found in all mammalian cells and contain hydrolases and lipases required for protein and membrane degradation. In many cells of the immune system, lysosomes also contain secretory proteins that can be released by regulated exocytosis in response to an external stimulus, providing different cell types with a wide range of effector functions. Melanosomes also use a lysosome-related organelle to secrete melanin for pigmentation. Links between albinism and immunity in patients have uncovered a number of key proteins required for lysosomal secretion and have revealed a versatile secretory mechanism that can be fine-tuned by distinct interactions in different cell types.