bluuebunny/crossref_metadata_2025 huggingface dataset:
Sanitary and phytosanitary measures in international trade: policy considerations vs. economic reasoning
Authors: Miljkovic Dragan
Published: April 2005

Sanitary and phytosanitary (SPS) measures are one form of non‐tariff international trade barrier with the objective of requiring consumer and intermediate goods to be safe and to provide information to protect consumers from deceptive practices. However, such barriers could severely restrict trade. The central strategy of the World Trade Organization's (WTO) SPS Agreement is to use science to distinguish between those SPS measures consistent with the Agreement and those in violation of the Agreement. SPS measures belong to what is known as trans‐science questions or questions which can be asked of science and yet which cannot be answered by science. Because of the presence of scientific uncertainty, science policies adopted by members should be identified by the WTO. WTO panels should not, however, establish scientific policies. Prohibitive measures would seem rather incompatible with the role the WTO assumed trying to promote free trade. Rather, facilitating the distribution of available information regarding SPS and food safety risk, or a lack of it, to consumers in importing countries would help them to make better informed decisions according to their own preferences and risk aversion.
Viability of Auction‐Based Revenue Management in Sequential Markets
Authors: Baker Tim , Murthy Nagesh N.
Published: April 2005

The Internet is providing an opportunity to revenue management practitioners to exploit the potential of auctions as a new price distribution channel. We develop a stochastic model for a high‐level abstraction of a revenue management system (RMS) that allows us to understand the potential of incorporating auctions in revenue management in the presence of forecast errors associated with key parameters. Our abstraction is for an environment where two market segments book in sequence and revenue management approaches consider auctions in none, one, or both segments. Key insights from our robust results are (i) limited auctions are best employed closest to the final sale date, (ii) counterbalancing forecast errors associated with overall traffic intensity and the proportion of customer arrivals in a segment is more important if an auction is adopted in that segment, and (iii) it is critically important not to err on the side of overestimating market willingness to pay.
Revenue Management in Order‐Driven Production Systems
Authors: Barut Mehmet , Sridharan V.
Published: April 2005

This article investigates the effectiveness of a tactical demand‐capacity management policy to guide operational decisions in order‐driven production systems. The policy is implemented via a heuristic that attempts to maximize revenue by selectively accepting or rejecting customer orders for multiple product classes when demand exceeds capacity constantly over the short term. The performance of the heuristic is evaluated in terms of its ability to generate a higher profit compared to a first‐come‐first‐served (FCFS) policy. The policies are compared over a wide range of conditions characterized by variations in both internal (firm) and external (market) factors. The heuristic, when used with a Whole Lot order‐processing approach, produces higher profit compared to FCFS when profit margins of products are substantially different from each other and demand exceeds capacity by a large amount. In other cases it is better to use the heuristic in conjunction with the Split Lot order‐processing approach.
Pleomorphic Ventricular Tachycardia: An Uncommon Presentation in Idiopathic Left Ventricular Tachycardia
Authors: YEH YUNG‐HSIN , LIN KUO‐HUNG , LUQMAN NAZAR , SUNG RUEY J. , KUO CHI‐TAI
Published: April 2005

Idiopathic left ventricular tachycardia (ILVT) is a distinct entity that arises in the left ventricle, may have reentrant mechanism and is verapamil‐sensitive. Pleomorphism as defined by multiple ventricular tachycardia morphologies is usually associated with either coronary artery disease or cardiomyopathy but very rare in cases of ILVT. In this case report, we describe an unusual case of ILVT with two ECG morphologies of the opposite axis that were successfully eliminated with radiofrequency ablation. The successful ablation sites were closely located to each other in the left lower ventricular septum.
Use of Advanced Mapping Systems to Guide Ablation in Complex Cases: Experience with Noncontact Mapping and Electroanatomic Mapping Systems
Authors: GUREVITZ OSNAT T. , GLIKSON MICHAEL , ASIRVATHAM SAMUEL , KESTER TAMMY A. , GRICE SUELLEN K. , MUNGER THOMAS M. , REA ROBERT F. , SHEN WIN‐KUANG , JAHANGIR ARSHAD , PACKER DOUGLAS L. , HAMMILL STEPHEN C. , FRIEDMAN PAUL A.
Published: April 2005

Objective: This report describes our experience with noncontact mapping and electroanatomic mapping in complex ablations, which are defined as ablations done after failure of conventional ablation.

Material and Methods: Patients were included (N = 68; 49% with structural heart disease) in whom previous ablation failed and in whom a second procedure was done with advanced mapping. Non‐contact mapping was used in 17 patients, electroanatomic mapping in 36, and both noncontact and electroanatomic mapping in 15. Arrhythmias included focal atrial tachycardia (n = 16), reentrant atrial tachycardia (n = 14), right ventricular outflow tachycardia (n = 10), post‐myocardial infarction ventricular tachycardia (n = 9), and others (n = 19).

Results: Acute success at the second ablation was achieved in 79% of patients. At 20 ± 9 months after the procedure, 69% of these patients reported having significantly fewer symptoms than before the second ablation, and 51% were free of symptoms. Only 16% were using antiarrhythmic medications. Complications included a small pericardial effusion in two patients, hypotension in one patient, and a femoral pseudoaneurysm in another.

Conclusions: Advanced mapping is a useful and safe adjunct for catheter ablation after ablation has failed in patients with complex substrate.
Outcome of Magnetic Resonance Imaging (MRI) in Selected Patients with Implantable Cardioverter Defibrillators (ICDs)
Authors: GIMBEL J. ROD , KANAL EMANUEL , SCHWARTZ KERRY M. , WILKOFF BRUCE L.
Published: April 2005

Objective: To determine if simple strategies used to safely scan pacemaker patients could be applied to implantable cardioverter defibrillator (ICD), patients undergoing MRI allowing ICD patients to undergo MRI as well.

Interventions: Screening, reprogramming, and monitoring strategies were used to facilitate MRI.

Results: Seven patients underwent eight MRI scans at 1.5 T. Post‐MRI, all devices demonstrated no change in pacing, sensing, impedances, charge times, or battery status. The patient undergoing a lumbar spine scan experienced a “power‐on‐reset” of his ICD without permanent impairment of his device.

Conclusion: Scanning of ICD patients might be performed if appropriate reprogramming and monitoring is implemented.
Cardiac Magnetic Resonance Imaging in a Patient with Implantable Cardioverter‐Defibrillator
Authors: ROGUIN A. , DONAHUE J.K. , BOMMA C.S. , BLUEMKE D.A. , HALPERIN H.R.
Published: April 2005

The presence of pacemakers and implantable cardioverter‐defibrillators (ICD) is considered historically a contraindication to magnetic resonance (MR) imaging. This image modality has unparalleled soft‐tissue imaging capabilities, and many consider it as the image of choice for patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C). ICDs are now smaller, with less magnetic materials and improved electromagnetic interference protection. We tested modern ICDs for heat, force, function and image distortion and found that several of them may indeed be MRI safe. We report here a patient who was suspected of ARVD/C, underwent ICD implantation based on MR safety testing, and underwent intentionally scheduled follow‐up cardiac MR imaging. This is the description of a patient with an ICD who had planned MRI scanning. The scan was safe and most of the MRI images were of high quality.
Current Clinical Issues for MRI Scanning of Pacemaker and Defibrillator Patients
Authors: KALIN RON , STANTON MARSHALL S.
Published: April 2005

Dramatic increases in both magnetic resonance imaging (MRI) usage and cardiac device‐based therapy have resulted in an estimated 50–75% probability of a patient being indicated for an MRI over the lifetime of their device. Some recent studies have demonstrated “safe procedures” and “no adverse events” in the limited populations, clinical situations, and specific devices and lead orientations tested. While these investigations are useful to help ascertain the hazards for patients with cardiac devices, they do not demonstrate clear freedom from risk. All components of active implantable systems must be engineered during the design stage to provide safety in current and evolving MR environments. Device manufacturers need to secure regulatory approval to confirm their products' safety under multiple clinical and technical variables.
The Determinants of Gender Equity in India: Examining Dyson and Moore's Thesis with New Data
Authors: Rahman Lupin , Rao Vijayendra
Published: April 2005

In revisiting the influential Dyson and Moore (1983) hypothesis as to why women in South India enjoy relatively more agency than in the North, we conducted an econometric analysis of the determinants of women's mobility and decisionmaking authority. Data for the study come from a household data survey carried out in the Northern state of Uttar Pradesh and in the Southern state of Karnataka in 1995. We find that cross‐cousin and uncle‐niece marriage is more prevalent in Karnataka as expected. Contrary to Dyson and Moore, however, by 1995 a majority of communities in both North and South practiced village exogamy, and dowries in the two regions were of similar size. Reduced‐form, multivariate regressions show that cultural factors affect women's autonomy in ways not earlier predicted. The impact of village exogamy is mixed rather than negative, while that of consanguinity is strongly negative rather than positive as Dyson and Moore surmised. These authors correctly identified the negative effect purdah has on female mobility. Consistent with economic theory, our data show that higher wages for women consistently improve their mobility and authority, while higher male wages decrease them. Improvements in infrastructure–particularly the presence of street lights and schools in the village–are associated with increased women's agency. We conclude, therefore, that economic factors, state action, and restrictions on mobility seem more powerful than kinship structures as explanations of differences in female autonomy between North and South India.
Sex Differentials in Childhood Feeding, Health Care, and Nutritional Status in India
Authors: Mishra Vinod , Roy T. K. , Retherford Robert D.
Published: April 2005

Strong preference for sons in South Asia is well documented, but evidence on female disadvantage in childhood feeding, health care, and nutritional status is inconclusive. This article examines sex differentials in indicators of childhood feeding, health care, and nutritional status of children under age 3 by birth order and sex composition of older living siblings. Data are from India's 1992–93 and 1998–99 National Family Health Surveys. The analysis finds three reasons for inconclusive evidence on female disadvantage in aggregate analyses. First, discrimination against girls is limited to the relatively small fraction of children of certain birth orders and sex compositions of older siblings. Second, discrimination against girls when boys are in short supply and discrimination against boys when girls are in short supply cancel each other to some extent. Third, some discrimination against girls (e.g., in exclusive breastfeeding at 6–9 months) is nutritionally beneficial to girls. Separate analyses for North and South India find that gender discrimination is as common in the South as in the North, where son preference is generally much stronger.
The Media Marketplace for Garbled Demography
Authors: Teitelbaum Michael S.
Published: April 2005

Differences in cultural norms and incentives provide a powerful marketplace for garbled demography in the mass media. Journalists are attracted to expectation of dramatic shifts in politically and socially controversial domains that can result from long‐term population projections. Demographers routinely caution against interpreting such projections as forecasts, and emphasize the complexities and uncertainties of demographic analyses. Yet such caveats are often lost in the sequence of translations from demographic study, to press release, to journalistic treatment. In addition, advocacy groups often interpret such stories to serve their own interests, while headlines and article titles designed for general readerships are another source of miscommunication about demographic studies. Two recent cases offer object lessons of how careful demographic analyses addressing politically controversial trends can suffer from such confusions: media coverage of the 1997 National Research Council report entitled The New Americans, and the 2000 report by the United Nations Population Division entitled Replacement Migration: Is It a Solution to Declining and Ageing Populations? The essay suggests procedural changes that might moderate the level of garbled reporting and commentary that commonly characterize coverage of such studies in the mass media.
Isolation and Characterization of a Novel Chitosan‐Binding Protein from Non‐Heading Chinese Cabbage Leaves
Authors: CHEN Hui‐Ping , XU Lang‐Lai
Published: April 2005

Abstract: To know the mechanism of ammonia assimilation in non‐heading Chinese cabbage (Brassica campestrish L. ssp. chinensis (L.) Makino) leaves regulated by chitosan (CTS), a CTS‐binding protein was isolated from non‐heading Chinese cabbage leaves using the chitosan affinity chromatography approach and this CTS‐binding protein was partially characterized. The profile of the 53.1 kDa purified protein on sodium dodecyl sulfate‐polyacrylamide gel electrophoresis was compared with the native molecular weight of 106.5 kDa, which indicated that the purified protein was a dimer with identical subunits. After isoelectric focusing, a band was obtained at pH 8.25. The agglutination test and periodic acid‐Schiff staining further revealed that the protein was a glycoprotein with lectin activity. Moreover, the purified protein contained 17.4% (w/w) neutral carbohydrate and 82.56% (w/w) protein. The comparison of this protein and the 67 kDa CTS‐binding protein isolated previously from Rubus culture tissue exhibited some differences in characterization. According to results of peptide mass fingerprinting analysis, the protein purified in the present study does not show any similarity with any protein in the protein data bank. Thus, it was deduced that the protein purified in the present study is a novel CTS‐binding protein.

(Managing editor: Li‐Hui ZHAO)
Isolation and Expression Pattern Analysis of Two Ferritin Genes in Tobacco
Authors: JIANG Ting‐Bo
Published: April 2005

Abstract: For understanding of the ferritin gene expression pattern and the mechanism of iron homeostasis in tobacco (Nicotiana tabaccum, L.) plants, two full‐length ferritin cDNAs, NtFer1, and NtFer2, were isolated from tobacco seedlings and characterized. These cDNAs are 1 214 and 1 125 bp nucleotides and encode 251 and 259 amino acid residues, respectively. The deduced amino acid sequences showed that two tobacco ferritins share the same characteristics as the plant ferritins from Arabidopsis, soybean, and maize. Southern blotting analysis indicated that both NtFer1, and NtFer2, were probably multicopy genes in the tobacco genome. Northern blotting analysis indicated that iron loading of tobacco plantlets increased the ferritin mRNA abundance and that NtFer1, expression was higher and more sensitive to iron than NtFer2 expression. Furthermore, NtFer1, was expressed in both leaves and roots, whereas NtFer2, was expressed mainly in leaves.

(Managing editor: Li‐Hui ZHAO)
WHY BANKS HAVE A FUTURE: TOWARD A NEW THEORY OF COMMERCIAL BANKING
Authors: Rajan Raghuram G.
Published: April 2005

According to some observers, the commercial bank–an institution that conducts the twin activities of accepting deposits payable on demand and originating loans–has outlived its usefulness and is in a state of terminal decline. The broad statistical evidence for this contention, however, is somewhat mixed. While some studies suggest that the role of banks in the United States is declining, others suggest that banks are simply using new vehicles to offer their services and that their role has not diminished at all.

This article takes a different approach to analyzing the future of banks by examining the economic rationale for their past existence and exploring the extent to which this rationale can be expected to hold up in the future. The author begins by explaining why the two core banking activities–taking in deposits payable on demand and originating non‐marketable loans–are performed by the same institutions. The explanation turns on the recognition that both activities essentially require the institution to come up with cash on short notice–that is, to provide liquidity. Scale economies in providing liquidity explain why both activities are provided by the same entity.

Deregulation and innovation have increased competition in the financial services industry, which has forced banks to concentrate on the essentials of liquidity provision. This is why the outward nature of banks' activities has changed (for example, banks today often sell instead of holding loans, and provide back‐up lines for commercial paper instead of originating loans), though not their underlying economic rationale (particularly the credit evaluation and monitoring involved in “relationship” banking).

Beneath the surface reality of dramatic changes in financial products and services, the fundamental banking business of liquidity provision is alive and well. Moreover, in the course of performing their traditional activities, banks have acquired competencies that enable them to perform a variety of other financial and nonfinancial activities that deregulation and innovation have opened up to them. As part of their evaluation of these nontraditional activities, bankers must ensure that their organizational structures, controls, and compensation policies are appropriate for the new environment of deregulation and technological change.
A NEW MODEL FOR ESTIMATING RISK PREMIUMS (ALONG WITH SOME EVIDENCE OF THEIR DECLINE)
Authors: Booth Laurence
Published: April 2005

This article uses the Gordon growth model with a novel method for forecasting dividend growth rates to estimate the equity cost and associated risk premium for a sample of Canadian telecommunications companies. The results suggest that the Telco risk premium has declined significantly since the early 1980s. Moreover, this decline is accentuated when measured over long Canada yields, rather than over similarly taxed, longterm preferred yields.

The findings of this study also suggest that the inverse relationship between utility risk premium and market interest rates reported by studies of U.S. utilities does not hold in Canada. If anything, the Telco risk premium has tended to vary directly with the level of market interest rates, with risk premium falling along with the general decline in rates. The main reason for these results seems to be the significant increase in interest rate risk, which has caused the long Canada yield to be a very poor proxy for the longterm, riskfree rate.

One practical implication of this finding is that companies that estimate equity costs as a premium over longterm government bond yields are probably seriously overestimating the cost.
Thermohydrodynamic Analysis of Surface Roughness in the Flow Field
Authors: Kim Joon Hyun , Kim Joo-Hyun
Published: April 2005

The study deals with the development of a thermohydrodynamic (THD) computational procedure for evaluating the pressure, temperature, and velocity distributions in fluid films with a very rough geometry. A parametric investigation is performed to predict the bearing behaviors in the lubricating film with the absorbed layers and their interfaces as determined by rough surfaces with Gaussian distribution. The layers are expressed as functions of the standard deviations of each surface to characterize flow patterns between both rough surfaces. Velocity variations and heat generation are assumed to occur in the central (shear) zone with the same bearing length and width. The coupled effect of the surface roughness and shear zone dependency on the hydrodynamic pressure and temperature has been found in the noncontact mode. The procedure confirms the numerically determined relationship between the pressure and film gap, provided that its roughness magnitude is smaller than the fluid film thickness.
Application of a Deterministic Contact Model to Analyze the Contact of a Rough Surface Against a Flat Layered Surface
Authors: Pasaribu H. R. , Schipper D. J.
Published: April 2005

In this paper, a rough surface is modeled as an array of asperities represented by spheres with different radii and heights to be able to calculate the deformation (elastic, elastic-plastic, and plastic) at each asperity in contact. The total contact area and the total load carried are calculated by summarizing respectively the contact area and the load carried by each individual asperity (deterministic model). This model will diminish the assumption of an average asperity radius and enable one to calculate the contact of non-Gaussian surface more precisely. Further, in this paper, the deterministic model is used to analyze the contact behavior of a rough surface against a flat layered surface by modeling the flat layered surface as a solid that has effective mechanical properties as a function of indentation depth.
Three‐dimensional fluorescence lifetime tomography
Authors: Godavarty Anuradha , Sevick‐Muraca Eva M. , Eppstein Margaret J.
Published: April 2005

Near‐infrared fluorescence tomography using molecularly targeted lifetime‐sensitive, fluorescent contrast agents have applications for early‐stage cancer diagnostics. Yet, although the measurement of fluorescent lifetime imaging microscopy (FLIM) is extensively used in microscopy and spectroscopy applications, demonstration of fluorescence lifetime tomography for medical imaging is limited to two‐dimensional studies. Herein, the feasibility of three‐dimensional fluorescence‐lifetime tomography on clinically relevant phantom volumes is established, using (i) a gain‐modulated intensified charge coupled device (CCD) and modulated laser diode imaging system, (ii) two fluorescent contrast agents, e.g., Indocyanine green and 3‐3’‐Diethylthiatricarbocyanine iodide differing in their fluorescence lifetime by 0.62 ns, and (iii) a two stage approximate extended Kalman filter reconstruction algorithm. Fluorescence measurements of phase and amplitude were acquired on the phantom surface under different target to background fluorescence absorption (70:1, 100:1) and fluorescence lifetime (1:1, 2.1:1) contrasts at target depths of 1.4–2 cm. The Bayesian tomography algorithm was employed to obtain three‐dimensional images of lifetime and absorption owing to the fluorophores.
A new data consistency condition for fan‐beam projection data
Authors: Chen Guang‐Hong , Leng Shuai
Published: April 2005

The sum of all attenuation data acquired in one view of parallel‐beam projections is a view angle independent constant. This fact is known as a data consistency condition on the two‐dimensional Radon transforms. It plays an important role in tomographic image reconstruction and artifact correction. In this paper, a novel fan‐beam data consistency condition (FDCC) is derived and presented. Using the FDCC, individual projection data in one view of fan‐beam projections can be estimated from filtering all other projection data measured from different view angles. Numerical simulations are performed to validate the new FDCC in correcting ring artifacts caused by malfunctioning detector cells.
Respiratory correlated cone beam CT
Authors: Sonke Jan‐Jakob , Zijp Lambert , Remeijer Peter , van Herk Marcel
Published: April 2005

A cone beam computed tomography (CBCT) scanner integrated with a linear accelerator is a powerful tool for image guided radiotherapy. Respiratory motion, however, induces artifacts in CBCT, while the respiratory correlated procedures, developed to reduce motion artifacts in axial and helical CT are not suitable for such CBCT scanners. We have developed an alternative respiratory correlated procedure for CBCT and evaluated its performance. This respiratory correlated CBCT procedure consists of retrospective sorting in projection space, yielding subsets of projections that each corresponds to a certain breathing phase. Subsequently, these subsets are reconstructed into a four‐dimensional (4D) CBCT dataset. The breathing signal, required for respiratory correlation, was directly extracted from the 2D projection data, removing the need for an additional respiratory monitor system. Due to the reduced number of projections per phase, the contrast‐to‐noise ratio in a 4D scan reduced by a factor 2.6–3.7 compared to a 3D scan based on all projections. Projection data of a spherical phantom moving with a 3 and 5 s period with and without simulated breathing irregularities were acquired and reconstructed into 3D and 4D CBCT datasets. The positional deviations of the phantoms center of gravity between 4D CBCT and fluoroscopy were small: for the regular motion and for the irregular motion. Motion artifacts, clearly present in the 3D CBCT datasets, were substantially reduced in the 4D datasets, even in the presence of breathing irregularities, such that the shape of the moving structures could be identified more accurately. Moreover, the 4D CBCT dataset provided information on the 3D trajectory of the moving structures, absent in the 3D data. Considerable breathing irregularities, however, substantially reduces the image quality. Data presented for three different lung cancer patients were in line with the results obtained from the phantom study. In conclusion, we have successfully implemented a respiratory correlated CBCT procedure yielding a 4D dataset. With respiratory correlated CBCT on a linear accelerator, the mean position, trajectory, and shape of a moving tumor can be verified just prior to treatment. Such verification reduces respiration induced geometrical uncertainties, enabling safe delivery of 4D radiotherapy such as gated radiotherapy with small margins.
Experimental validation of the Wigner distributions theory of phase‐contrast imaging
Authors: Donnelly Edwin F. , Price Ronald R. , Pickens David R.
Published: April 2005

Recently, a new theory of phase‐contrast imaging has been proposed by Wu and Liu [Med. Phys. 31, 2378–2384 (2004)]. This theory, based upon Wigner distributions, provides a much stronger foundation for the evaluation of phase‐contrast imaging systems than did the prior theories based upon Fresnel‐Kirchhoff diffraction theory. In this paper, we compare results of measurements made in our laboratory of phase contrast for different geometries and tube voltages to the predictions of the Wu and Liu model. In our previous publications, we have used an empirical measurement (the edge enhancement index) to parametrize the degree of phase‐contrast effects in an image. While the Wu and Liu model itself does not predict image contrast, it does measure the degree of phase contrast that the system can image for a given spatial frequency. We have found that our previously published experimental results relating phase‐contrast effects to geometry and x‐ray tube voltage are consistent with the predictions of the Wu and Liu model.
Suitability of radiochromic medium for real‐time optical measurements of ionizing radiation dose
Authors: Rink Alexandra , Vitkin I. Alex , Jaffray David A.
Published: April 2005

A system, consisting of a novel optical fiber‐based readout configuration and model‐based method, has been developed to test suitability of a certain radiochromic medium for real‐time measurements of ionizing radiation dose. Using this system with the radiochromic film allowed dose measurements to be performed during, and immediately after, exposure. The rates of change in OD before, during, and after exposure differ, and the change in OD during exposure was found to be proportional to applied dose in the tested range of 0–4 Gy. Estimating applied dose within an average error of less than 5% did not require a waiting time of 24–48 h as generally recommended with this radiochromic film. The errors can be further reduced by performing a calibration for each individual dosimeter setup instead of relying on batch calibration. Measurements of change in OD were found to be independent of dose‐rate in the 95–570 cGy/min range for applied dose of 1 Gy or less. Some error was introduced due to dose‐rate variation for doses of 2 Gy and above. The major limiting factor in utilizing this radiation sensitive medium for real‐time in vivo dosimetry is the strong dependence on temperature in the clinically relevant range of 20–38 °C.
Combination of dosimetry for targeted radionuclide and external beam therapies
Authors: Bodey Rachel K.
Published: April 2005

In this thesis, issues relevant to the combined use and dosimetry of external beam radiotherapy (EBT) and targeted radionuclide therapy (TRT) are addressed. Methodology was developed to allow a combination of dose information from these two modalities, employing the biologically effective dose (BED) to address the inequivalence of biological effect. It was found that use of this combined modality radiotherapy (CMRT) could result in increased conformality of treatments and reduced doses to normal tissues compared with dose delivery by EBT alone. A model was developed to investigate the radiobiological effects that may arise if the two therapies were delivered concurrently. It was found that under most clinical conditions, the relative temporal delivery of these two therapies is unlikely to significantly influence the overall radiobiological effect to the tumour at the cellular level. Synergistic effects may be more significant in normal tissues and for tumours with low values of . The accuracy with which single photon emission computed tomography (SPECT) can be quantified for TRT dosimetry applied to CMRT was assessed via an phantom imaging study. Good agreement was found between the modeled and experimental data, but recovery of the object by deconvolution was found to be unsuccessful due to the limited spatial resolution of the system and noise content in the image. may therefore be unsuitable for this application. The incorporation of intensity modulated radiotherapy (IMRT) into CMRT was investigated, exploring both physically and biologically based methods of prescribing a nonuniform EBT dose distribution according to the distribution of TRT uptake. This approach was found to be feasible with IMRT providing sufficient dose modulation. The nonuniform EBT prescription can often be reduced to the simpler uniform case if planned as a component of CMRT and the effects of delivery errors are taken into account. In general, it has been found that a combination of EBT and TRT allows normal tissue doses to be reduced compared with dose delivery by EBT alone, and more satisfactory doses in the target to be reached. Methodology developed is applicable both to biologically based radiotherapy planning and to the wider concepts of combined modality therapies.
Brain tumors and synchrotron radiation: Methodological developments in quantitative brain perfusion imaging and radiation therapy
Authors: Adam Jean‐François
Published: April 2005

High‐grade gliomas are the most frequent type of primary brain tumors in adults. Unfortunately, the management of glioblastomas is still mainly palliative and remains a difficult challenge, despite advances in brain tumor molecular biology and in some emerging therapies. Synchrotron radiation opens fields for medical imaging and radiation therapy by using monochromatic intense x‐ray beams. It is now well known that angiogenesis plays a critical role in the tumor growth process and that brain perfusion is representative of the tumor mitotic activity. Synchrotron radiation quantitative computed tomography (SRCT) is one of the most accurate techniques for measuring in vivo contrast agent concentration and thus computing precise and accurate absolute values of the brain perfusion key parameters. The methodological developments of SRCT absolute brain perfusion measurements as well as their preclinical validation are detailed in this thesis. In particular, absolute cerebral volume and blood brain barrier permeability high‐resolution (pixel size ) parametric maps were reported. In conventional radiotherapy, the treatment of these tumors remains a delicate challenge, because the damages to the surrounding normal brain tissue limit the amount of radiation that can be delivered. One strategy to overcome this limitation is to infuse an iodinated contrast agent to the patient during the irradiation. The contrast agent accumulates in the tumor, through the broken blood brain barrier, and the irradiation is performed with kilovoltage x rays, in tomography mode, the tumor being located at the center of rotation and the beam size adjusted to the tumor dimensions. The dose enhancement results from the photoelectric effect on the heavy element and from the irradiation geometry. Synchrotron beams, providing high intensity, tunable monochromatic x rays, are ideal for this treatment. The beam properties allow the selection of monochromatic irradiation, at the optimal energy, for a maximal dose deposit in the tumor, while sparing healthy tissues. The methodology, the associated dosimetry as well as the preclinical validation of iodine enhanced strereotactic synchrotron radiation therapy is developed in the thesis. Significant survival increases were obtained, especially when the delivery of iodine is coupled with a transient blood–brain–barrier opener. The two complementary methods developed in this thesis offer perspectives in the understanding of the glioma growth process and in their treatment by radiation therapy. They show the potential of synchrotron radiation for absolute high‐resolution morphological and functional CT imaging, and for new therapeutic modalities using intense monochromatic x rays.
Distributions of decayed nuclei generated in the and targets by the target nuclear fragment reaction using therapeutic MONO and SOBP proton beam
Authors: Nishio Teiji , Sato Takashi , Kitamura Hideaki , Murakami Koji , Ogino Takashi
Published: April 2005

In proton radiotherapy, the irradiation dose can be concentrated on a tumor. To use this radiotherapy efficiently in the clinical field, it is necessary to evaluate the proton‐irradiated area and condition. The proton‐irradiated area can be confirmed by coincidence detection of pair annihilation gamma rays from decayed nuclei generated by target nuclear fragment reaction of irradiated proton nuclei and nuclei in the irradiation target. In this study, we performed experiments of proton irradiation to a polyethylene target containing nuclei, which is a major component of the human body, and a gelatinous water target containing nuclei at different proton irradiation energy levels under different beam conditions of mono‐energetic Bragg peak and spread‐out Bragg peak. The distribution of the activity in the target after proton irradiation was measured by a positron emission tomography (PET) apparatus, and compared with the calculated distribution. The temporal dependence of the activity distribution during the period between the completion of proton irradiation and the start of measurement by the PET apparatus was examined. The activity by clinical proton irradiation was in the PE target and in the water target, indicating that the intensity was sufficient for the evaluation of the distribution. The range of the activity distribution against the physical range was short (several millimeter water equivalent length), indicating the presence of target dependence. The range difference in the water target was slightly large with time dependence until the start of measurement. The difference of the lateral widths with full width half at maximum in the distributions of the measured irradiated dose and activity was within .
Improved accuracy and consistency in measurement of flowing blood by using inversion recovery GE‐EPI
Authors: Guo Jun‐Yu , Kim Seong‐Eun , Parker D. L. , Jeong E. K. , Zhang Ling , Roemer R. B.
Published: April 2005

Problems associated with techniques currently used to measure the of flowing blood are evaluated and a method to improve the consistency and repeatability of measurements is presented. Similar to some currently used techniques, the pulse sequence employs a nonselective adiabatic inversion pulse followed by a series of ECG‐gated gradient echo EPI (echo planar imaging) images to obtain images where the blood (fluid) signal exhibits a ‐dependent inversion recovery signal from which the spin lattice relaxation constant of the flowing fluid can be measured. The new method combines curve fitting with a measure of the curve null point to acquire more accurate and consistent values. Simulation and experimental results show that this combined fitting‐nulling method is more stable and consistent in measuring the of flowing fluid. The feasibility of temperature measurement of a flowing fluid based on the temperature dependence of the of water protons is shown in this paper. ECG gating is used to reduce the effects of cyclic intensity changes for measurement of in pulsatile flowing blood.
Near‐real‐time radiotherapy dosimetry using optically stimulated luminescence of : Mathematical models and preliminary results
Authors: Gaza R. , McKeever S. W. S. , Akselrod M. S.
Published: April 2005

In this paper we report investigations aimed toward applying optically stimulated luminescence (OSL) of for near‐real‐time medical dosimetry, especially in radiotherapy. The classical mathematical model normally used for the description of OSL phenomena was expanded to predict the behavior of the luminescence signal in the case when the OSL sample is simultaneously irradiated and optically stimulated. The predictions obtained were used to develop different measurement approaches and correction algorithms for the luminescence signals, thus enabling dose estimation from OSL during rather then after the irradiation procedure. Radiation probes with diameters of less than 1 mm, suitable for the envisioned in‐vivo measurements were constructed by attaching small crystals to optical fiber cables. The OSL fiber probes and a purpose‐built, portable OSL stimulation and readout system were used to measure doses at speeds up to 1 data point every 3s, under irradiation at dose rates of the same order of magnitude as those found in conventional radiotherapy techniques. The corrected OSL signal was found to be proportional to the absorbed dose, and accurately followed sudden transitions in the irradiation dose rate.
Prospective Evaluation of a Whole-Blood Test Using
Mycobacterium tuberculosis
-Specific Antigens ESAT-6 and CFP-10 for Diagnosis of Active Tuberculosis
Authors: Ravn Pernille , Munk Martin E. , Andersen Åse B. , Lundgren Bettina , Lundgren Jens D. , Nielsen Lars N. , Kok-Jensen Axel , Andersen Peter , Weldingh Karin
Published: April 2005

A new immunodiagnostic test based on the
Mycobacterium tuberculosis
-specific antigens CFP-10/ESAT-6(QFT-RD1) has been launched as an aid in the diagnosis of latent tuberculosis (TB) infection (LTBI). The aim of this study was to evaluate this test for the diagnosis of active TB. Eighty-two patients with suspicion of TB and 39 healthy BCG-vaccinated persons were enrolled. Forty-eight had active TB, 25 did not, and 9 were excluded. Sensitivity and specificity of the test for active TB were evaluated in a prospective blinded manner in patients suspected of TB. The sensitivity of the QFT-RD1 was 85% (40/48; confidence interval [CI], 75 to 96), and it was higher than the sensitivity of microscopy, 42% (20/48; CI, 27 to 56;
P
= 0.001), and culture, 59% (27/46; CI, 44 to 73;
P
= 0.009). Of patients with extrapulmonary TB, 92% (12/13) were QFT-RD1 positive, whereas only 31% (4/13) were positive by microscopy and 42% (5/12) by culture (
P
< 0.05), and 87% (13/15) of those who were negative by both microscopy and culture were QFT-RD1 positive. By combining microscopy and culture with the QFT-RD1 test, sensitivity increased to 96% (CI, 90 to 102). Ten of 25 (40%) non-TB patients were QFT-RD1 positive, resulting in a specificity of 60%. However, 80% (8/10) of these had risk-factors for TB, indicating latent infection in this group. In healthy controls, only 3% (1/39) were QFT-RD1 positive. In conclusion, the QFT-RD1 test is sensitive for diagnosis of TB, especially in patients with negative microscopy and culture. The accuracy of the QFT-RD1 test will vary with the prevalence of LTBI. We suggest that the QFT-RD1 test could be a very useful supplementary tool for the diagnosis of TB.
Persisting Humoral Antiviral Immunity within the Japanese Population after the Discontinuation in 1976 of Routine Smallpox Vaccinations
Authors: Hatakeyama Shuji , Moriya Kyoji , Saijo Masayuki , Morisawa Yuji , Kurane Ichiro , Koike Kazuhiko , Kimura Satoshi , Morikawa Shigeru
Published: April 2005

Concerns have arisen recently about the possible use of smallpox for a bioterrorism attack. Routine smallpox vaccination was discontinued in Japan in 1976; however, it is uncertain exactly how long vaccination-induced immunity lasts. We sought to evaluate the seroprevalence and intensity of anti-smallpox immunity among representatives of the present Japanese population. The subjects included 876 individuals who were born between 1937 and 1982. Vaccinia virus-specific immunoglobulin G (IgG) levels were measured by enzyme-linked immunosorbent assay (ELISA), and 152 of 876 samples were also tested for the presence of neutralizing antibodies. Of the subjects who were born before 1962, between 1962 and 1968, and between 1969 and 1975, 98.6, 98.6, and 66.0%, respectively, still retained the vaccinia virus-specific IgG with ELISA values for optical density at 405 nm (OD
405
) of ≥0.10. The corresponding figures for retained IgGs with OD
405
values of ≥0.30 were 91.0, 90.3, and 58.2%, respectively. Neutralizing antibodies were also maintained. The sera with OD
405
values of ≥0.30 showed 89% sensitivity and a 93% positive predictive value for detection of neutralizing antibodies (≥4). Thus, approximately 80% of persons born before 1969 and 50% of those born between 1969 and 1975 were also found to have maintained neutralizing antibodies against smallpox. A considerable proportion of the previous vaccinated individuals still retain significant levels of antiviral immunity. This long-lasting immunity may provide some protective benefits in the case of reemergence of smallpox, and the disease may not spread as widely and fatally as generally expected.
Real-Time Reverse Transcription-PCR Quantitation of Substance P Receptor (NK-1R) mRNA
Authors: Lai Jian-Ping , Douglas Steven D. , Wang Yan-Jian , Ho Wen-Zhe
Published: April 2005

The substance P (SP)-preferring receptor, neurokinin-1 receptor (NK-1R), has an important role in inflammation, immune regulation, and viral infection. We applied a newly developed real-time reverse transcription (RT)-PCR assay to quantify NK-1R mRNA in human neuronal cell line (NT-2N), a human B-cell line (IM9), monocyte-derived macrophages (MDM), peripheral blood lymphocytes (PBL), and human astroglioma cells (U87 MG). The NK-1R real-time RT-PCR assay has a sensitivity of 100 mRNA copies, with a dynamic range of detection between 102and 107copies of NK-1R gene transcripts per reaction. This assay is highly reproducible, with an intraassay coefficient variation of threshold cycle (Ct) of less than 1.9%. The NK-1R real-time RT-PCR is highly sensitive for quantitative determination of NK-1R mRNA in human immune cells (MDM and PBL) that express low levels of NK-1R mRNA. In addition, the assay has the ability to accurately quantitate the dynamic changes in NK-1R mRNA expression in interleukin-1β-stimulated U87 MG. These data indicate that the NK-1R real-time RT-PCR has potential for a wide application in investigation of NK-1R expression at the mRNA level under physiological and pathological conditions in both the central nervous system and the immune system.
Development and Evaluation of a Western Blot Kit for Diagnosis of Schistosomiasis
Authors: Sulahian Annie , Garin Yves Jean François , Izri Arezki , Verret Caroline , Delaunay Pascal , van Gool Tom , Derouin Francis
Published: April 2005

We evaluated the performance of Western blot (WB) analysis using commercially available antigen strips and compared the results with those of indirect hemagglutination (IHA) and indirect immunofluorescence (IFAT) for the serodiagnosis of human schistosomiasis. The antigen preparation was a crude extract ofSchistosoma mansoni. The WB profile characteristics of schistosomiasis were characterized by comparing the results for 58 serum samples from patients with parasitologically provenS. mansoni(n= 12) andS. haematobium(n= 46) infections and 37 individuals with probable cases of schistosomiasis but with only positive serology results. The specificity of WB analysis was assessed by testing 12 serum samples from healthy subjects, 67 serum samples from patients with other proven helminthic and protozoan infections, and 16 serum samples from patients with autoantibodies. Six immunodominant bands (65, 70, 80, 95, 110, and 120 kDa) were revealed with sera from patients with schistosomiasis. The presence of three or more bands in the range 65 to 120 kDa, with the exception of the 100-kDa band, was considered diagnostic forSchistosomainfection and had a specificity of 100% in our series. In patients with proven schistosomiasis, the sensitivity of WB analysis was 84.5%, whereas those of IFAT and IHA were 65.5 and 72.9%, respectively. For serologically proven cases, the sensitivity of WB analysis was 97.3%. The overall sensitivity and specificity for both groups of patients were 89.5 and 100%, respectively, with positive and negative predictive values of 100 and 91.3%, respectively. We conclude that WB analysis is a useful technique for the immunological diagnosis of schistosomiasis.
NOVEL VOLTAGE-MODE UNIVERSAL FILTER USING ONLY TWO CDBAs
Authors: MAHESHWARI SUDHANSHU , KHAN IQBAL A.
Published: April 2005

A novel voltage-mode universal filter employing only two current differencing buffered amplifiers (CDBAs) is proposed. The filter uses four inputs and single output to realize six responses, viz. low-pass, high-pass, inverting band-pass, noninverting band-pass, band-elimination, and all-pass through input selection with independent pole-Q control. Computer simulation results using SPICE are also given to verify the theory.
DUAL FUNCTION CAPABILITY OF RECENTLY PROPOSED FOUR-CURRENT-CONVEYOR-BASED VM BIQUAD
Authors: SINGH VINOD KUMAR , SINGH ABDHESH K. , SENANI RAJ
Published: April 2005

This letter shows how, by simple modifications, the four-current-conveyor (CC) voltage mode biquad filter recently proposed by Singh and Senani provides dual function capability, i.e., the same circuit also yields all the five current-mode (CM) filters.
POWER-SPEED TRADE-OFF IN PARALLEL PREFIX CIRCUITS
Authors: VANICHAYOBON S. , DHALL S. K. , LAKSHMIVARAHAN S. , ANTONIO J. K.
Published: April 2005

Optimizing area and speed in parallel prefix circuits has been considered important for a long time. The issue of power consumption in these circuits, however, has not been addressed. This paper presents a comparative study of different parallel prefix circuits from the point of view of power–speed trade-off. An effective circuit capacitance model that is verified through PSpice simulations is used to investigate the power consumption in parallel prefix circuits. The model results in an analytical function for power consumption for each prefix circuit considered. The degrees of freedom studied include different parallel prefix circuits and voltage scaling. The results of the study were applied to evaluate power–speed trade-offs when different prefix circuits are used in Brent's parallel adder.5