bluuebunny/crossref_metadata_2025 huggingface dataset:
A Blueprint for Social Cognitive Development
Authors: Olson Kristina R. , Dweck Carol S.
Published: May 2008

The field of social cognitive development (SCD) has historically failed to emerge as a dominant approach in developmental psychology. We take this opportunity to articulate the assumptions, goals, and contributions of SCD with the aim of invigorating research from this perspective. We begin by describing the current landscape of social and cognitive development, suggesting what they have and have not given us. We then outline major goals of the social cognitive developmental approach and walk through examples of successful SCD research. Finally, we examine the unique potential of the social cognitive approach to cross-fertilize social and cognitive development (as well as related fields such as social psychology and neuroscience) and to answer new questions about development.
Hedonomics: Bridging Decision Research With Happiness Research
Authors: Hsee Christopher K. , Hastie Reid , Chen Jingqiu
Published: May 2008

One way to increase happiness is to increase the objective levels of external outcomes; another is to improve the presentation and choices among external outcomes without increasing their objective levels. Economists focus on the first method. We advocate the second, which we call hedonomics. Hedonomics studies (a) relationships between presentations (how a given set of out-comes are arranged among themselves or relative to other outcomes) and happiness and (b) relationships between choice (which option among alternative options one chooses) and happiness.
Patient satisfaction with nurse practitioner care in emergency departments in Canada
Authors: Thrasher Christine , Purc‐Stephenson Rebecca
Published: May 2008

Purpose: To measure patient satisfaction with care delivered by nurse practitioners (NPs) in emergency departments (EDs) in Canada using a psychometrically valid survey.

Data sources: All patients who received care from an NP in six participating EDs in Ontario province over a 1‐week period were asked to complete a self‐administered patient satisfaction survey designed specifically to assess satisfaction with NP care in EDs.

Conclusions: One hundred and thirteen patients completed the survey. Principal components analysis of the survey revealed three factors or subscales: Attentiveness, Comprehensive care, and Role clarity. Scores on the three subscales indicated that patients were satisfied with Attentiveness (M = 3.72, SD = 0.38) and Comprehensive care (M = 3.52, SD = 0.49) and had a moderate understanding of Role clarity (M = 2.99, SD = 0.66). Participants with higher income levels reported higher levels of satisfaction with the attentiveness they received, whereas patients with previous experience with an NP reported higher levels of satisfaction with the comprehensive care they received. There was no appreciable increase in patient satisfaction with the NP based on age, gender, education, or health status.

Implications for practice: These findings indicate that attentiveness, comprehensive care, and role clarity are reflected by the NP in emergency healthcare settings as indicated by the patient‘s responses to the survey. This study supports that meeting expectations is a critical component of patient satisfaction.
Characterizing nurse practitioner practice by sampling patient encounters: An APRNet study
Authors: Deshefy‐Longhi Terry , Swartz Martha K. , Grey Margaret
Published: May 2008

Purpose: The purpose of this study was to characterize nurse practitioners’ (NPs’) practice by using reports of patient encounters to more accurately reflect practice patterns than has been previously performed. This study was part of a larger primary care practice survey by a consortium of 20 practice‐based research networks (PBRNs). Therefore, comparisons, when appropriate, were also made between this network of NPs (Advanced Practice Registered Nurse Network, APRNet) and the other 19 physician‐run research networks.

Data sources: A descriptive survey was developed by the 20 PBRN consortium under grants from the Agency for Healthcare Research and Quality. The consortium’s goal was to collect primary care data over a 6‐month period and to document and compare primary care practice in the United States. The data were collected immediately following members’ encounters with patients rather than from billing spreadsheets. Nineteen PBRNs may have had NPs in the practices that comprised their networks. However, the data from these NPs were collected under the study ID numbers of the physician owners of each practice. APRNet, therefore, was the sole research network comprised exclusively of NPs who collected and reported data under their own study ID numbers.

Conclusions: Acute health problems comprised 45% of all episodes treated by NPs compared to 30% of episodes for exacerbations of chronic conditions and 24.5% for nonillness and health promotion visits. In addition, our findings suggest that NPs provide counseling in 84% (vs. 61% for physicians) of their primary care visits, regardless of the reason for visit, and the type of counseling varies by the type of NP.

Implications for practice: Despite many studies on the comparability and outcomes of NP practice, the need to identify, clarify, and document the practices of NPs in primary care settings remains. The present survey provides an important and useful first step in providing a systematic way to characterize these practices through a survey of APRNs immediately following their patient encounters.
Overweight and obesity in nurses, advanced practice nurses, and nurse educators
Authors: Miller Sally K. , Alpert Patricia T. , Cross Chad L.
Published: May 2008

Purpose: To quantify the incidence of overweight and obesity in nursing professionals and assess nurses’ knowledge of obesity and associated health risks.

Data sources: A mailed survey to 4980 randomly selected registered nurses from one state in each of six geographic regions. Response rate was 15.5% (n= 760). Descriptive statistics were calculated for continuous variables; categorical variables were summarized with frequency counts.

Results: The grand mean body mass index (BMI) of nurses surveyed was 27.2. Almost 54% were overweight or obese. Fifty‐three percent of these nurses report that they are overweight but lack the motivation to make lifestyle changes. Forty percent are unable to lose weight despite healthy diet and exercise habits. Only 26% of respondents use BMI to make clinical judgments of overweight and obesity. Although 93% of nurses acknowledge that overweight and obesity are diagnoses requiring intervention, 76% do not pursue the topic with overweight and obese patients.

Discussion: Many nurses provide weight‐related health information to the public. These data suggest that they may benefit from continuing education on obesity and its risks. Because 76% of nurses do not pursue the topic of obesity with patients, they may benefit from education on pursuing sensitive topics during a professional encounter. Nurse practitioners may play a key role in the education of both patients and registered nurses.
Characterization of the Photochromic Pigments in Red Fluorescent Proteins Purified from the Gut Juice of the Silkworm Bombyx mori L.
Authors: Sunagar Santosh G. , Lakkappan Vinod J. , Ingalhalli Susheela S. , Savanurmath Chandrashekar J. , Hinchigeri Shivyogeppa B.
Published: May 2008

Multiple forms of red fluorescent proteins (RFPs) were observed in the gut juice of the silkworm, Bombyx mori L. It is to be noted that only one RFP band is reported in the literature so far. However, we report here three electrophoretically separated RFPs (A, B and C) found to be heterogeneous with respect to their components, namely the protein part and the fluorescent tetrapyrrole pigment moiety. Of the three RFPs, band C was found to be a glycoprotein. The absorption extinction coefficients and fluorescence quantum yields of the three RFPs were estimated. Further, this is the first communication demonstrating the presence of three different chlorophyll derivatives associated with the three different RFPs. The pigments were analyzed by thin layer chromatography followed by their elution to characterize the pigments by spectrophotometric and spectrofluorometric methods. Spectral characteristics have led to the identification of monovinyl chlorophyllide a, divinyl protochlorophyllide a and monovinyl pheophytin a as being associated with RFP bands A, B and C, respectively. These three purified RFPs can serve as the source of the three pigments as the standards.
U‐Pb Age Determination for Seven Standard Zircons using Inductively Coupled Plasma–Mass Spectrometry Coupled with Frequency Quintupled Nd‐YAG (λ = 213 nm) Laser Ablation System: Comparison with LA‐ICP‐MS Zircon Analyses with a NIST Glass Reference Material
Authors: Orihashi Yuji , Nakai Shun’ichi , Hirata Takafumi
Published: May 2008

This paper evaluates the analytical precision, accuracy and long‐term reliability of the U‐Pb age data obtained using inductively coupled plasma–mass spectrometry (ICP‐MS) with a frequency quintupled Nd‐YAG (λ = 213nm) laser ablation system. The U‐Pb age data for seven standard zircons of various ages, from 28 Ma to 2400 Ma (FCT, SL13, 91500, AS3, FC1, QGNG and PMA7) were obtained with an ablation pit size of 30 μm diameter. For 207Pb/206Pb ratio measurement, the mean isotopic ratio obtained on National Institute of Standards and Technology (NIST) SRM610 over 4 months was 0.9105 ± 0.0014 (n = 280, 95% confidence), which agrees well with the published value of 0.9096. The time‐profile of Pb/U ratios during single spot ablation showed no significant difference in shape from NIST SRM610 and 91500 zircon standards. These results encouraged the use of the glass standard as a calibration standard for the Pb/U ratio determination for zircons with shorter wavelength (λ = 213 nm) laser ablation. But 206Pb/238U and 207Pb/235U ages obtained by this method for seven zircon standards are systematically younger than the published U‐Pb ages obtained by both isotope dilution–thermal ionization mass spectrometry (ID‐TIMS) and sensitive high‐resolution ion‐microprobe (SHRIMP). Greater discrepancies (3–4% younger ages) were found for the 206Pb/238U ages for SL13, AS3 and 91500 zircons. The origin of the differences could be heterogeneity in Pb/U ratio on SRM610 between the different disks, but a matrix effect accuracy either in the ICP ion source or in the ablation‐transport processes of the sample aerosols cannot be neglected. When the 206Pb/238U (= 0.2302) newly defined in the present study is used, the measured 206Pb/238U and 207Pb/235U ages for the seven zircon standards are in good agreement with those from ID‐TIMS and SHRIMP within ±2%. This suggests that SRM610 glass standard is suitable for ICP‐MS with laser ablation sampling (LA‐ICP‐MS) zircon analysis, but it is necessary to determine the correction factor for 206Pb/238U by measuring several zircon standards in individual laboratories.
Syntectonic Mobility of Supergene Nickel Ores of New Caledonia (Southwest Pacific). Evidence from Garnierite Veins and Faulted Regolith
Authors: Cluzel Dominique , Vigier Benoit
Published: May 2008

Supergene nickel deposits of New Caledonia that have been formed in the Neogene by weathering of obducted ultramafic rocks are controlled by fracture development. The relationship of tropical weathering and tectonic structures, faults and tension gashes, have been investigated in order to determine whether fractures play a passive role only, as previously thought; or alternatively, if brittle tectonics was acting together with alteration. Observation of time‐relationship, textures, and mineralogy of various fracture fills and fault gouges shows that active faulting has played a prominent role not only in facilitating drainage and providing room for synkinematic crystallization of supergene nickel silicate, but also in mobilizing already formed sparse nickel ore, producing the very high grade ore nicknamed “green gold”.
The Safety and Efficacy of High‐Dose Alefacept Compared With a Loading Dose of Alefacept in Patients With Chronic Plaque Psoriasis
Authors: Cafardi Jennifer A. , Cantrell Wendy , Wang Wenquan , Elmets Craig A. , Elewski Boni E.
Published: May 2008

Objectives
. Alefacept is a biologic response modifier indicated for moderate to severe psoriasis; it has been available since 2003. It is typically administered in a dosing regimen of 15 mg intramuscularly (IM) weekly for 12 weeks. The purpose of this study was to determine whether a higher dose may be more beneficial in achieving a 75% reduction in the Psoriasis Area and Severity Index (PASI 75). A secondary objective of this study was to examine whether increasing the dose during the initial course of alefacept would reduce the time to onset of efficacy and overall response rate. Two separate dosing regimens are evaluated in this study: 30 mg IM for 6 weeks followed by 15 mg IM for 6 weeks (group 1) and alefacept 30 mg IM weekly for 12 weeks (group 2).

Methods
. Efficacy was assessed using the PASI, Physician Global Assessment, body surface area, and photographic evaluation of a target lesion. A total of 20 patients enrolled and were randomized, 16 of whom completed the study. Data analyses were performed on a per‐protocol basis.

Results
. Overall, the mean PASI scores progressively decreased, with 43.8% reaching a 50% reduction in the PASI (PASI 50) at week 14 evaluation. Of these participants, 37.5% were in group 1 and 50% were treated with alefacept 30 mg IM for 12 weeks (group 2). Although our sample size was small, 12.5% of patients (one patient in each treatment arm) reached PASI 75. The most common adverse events encountered in this trial were mild infection, headache, pruritus, and erythroderma. There were no infections associated with a CD4+ cell count <250 cells/mm3.

Conclusions
. There was no difference between the treatment groups in achieving PASI 50 or PASI 75. In addition, in our small population, the higher doses of alefacept were associated with increased adverse effects, including erythroderma.
The Role of Ultrafiltration in the Management of Heart Failure
Authors: Costanzo Maria Rosa
Published: May 2008

Congestion causes the majority of hospitalizations for heart failure and contributes to heart failure progression and mortality. Intravenous loop diuretics reduce the signs and symptoms of congestion. Loop diuretics, however, may be associated with increased morbidity and mortality due to deleterious effects on neurohormonal activation, electrolyte balance, and cardiac and renal function. Ultrafiltration, an alternative method of sodium and water removal, safely improves hemodynamics in heart failure patients. Recent clinical trial data suggest that ultrafiltration may also reduce rehospitalizations for worsening heart failure.
Nonsteroidal Anti‐Inflammatory Drugs and the Heart: What Is the Danger?
Authors: Mukherjee Debabrata
Published: May 2008

Nonsteroidal anti‐inflammatory drugs (NSAIDs) and selective cyclooxygenase (COX‐2) inhibitors, or “coxibs,” are used for a number of disease conditions for relief of pain and inflammation. Currently available data suggest concern for prothrombotic risk with coxibs and some NSAIDs, and the magnitude of risk may vary with individual agents. NSAIDs and coxibs also increase blood pressure, worsen hypertension control, and may precipitate heart failure, with important differences among agents. Physicians should consider patterns of risk and benefit in selecting the most appropriate agent for individual patients based on the individual gastrointestinal and cardiovascular risk profile.
Vibration Tailoring of a Polar Orthotropic Circular Plate With a Translational Spring
Authors: Elishakoff Isaac , Pentaras Demetris
Published: May 2008

In this study, the vibration tailoring problem is analytically solved for the polar orthotropic circular plate with translational spring along its circumference. By using the semi-inverse method and postulating the mode shape as a polynomial, we derive a closed-form solution.
A model‐based framework for the detection of spiculated masses on mammographya)
Authors: Sampat Mehul P. , Bovik Alan C. , Whitman Gary J. , Markey Mia K.
Published: May 2008

The detection of lesions on mammography is a repetitive and fatiguing task. Thus, computer‐aided detection systems have been developed to aid radiologists. The detection accuracy of current systems is much higher for clusters of microcalcifications than for spiculated masses. In this article, the authors present a new model‐based framework for the detection of spiculated masses. The authors have invented a new class of linear filters, spiculated lesion filters, for the detection of converging lines or spiculations. These filters are highly specific narrowband filters, which are designed to match the expected structures of spiculated masses. As a part of this algorithm, the authors have also invented a novel technique to enhance spicules on mammograms. This entails filtering in the radon domain. They have also developed models to reduce the false positives due to normal linear structures. A key contribution of this work is that the parameters of the detection algorithm are based on measurements of physical properties of spiculated masses. The results of the detection algorithm are presented in the form of free‐response receiver operating characteristic curves on images from the Mammographic Image Analysis Society and Digital Database for Screening Mammography databases.
Investigation of intensity‐modulated radiotherapy optimization with gEUD‐based objectives by means of simulated annealing
Authors: Hartmann Matthias , Bogner Ludwig
Published: May 2008

Inverse treatment planning of intensity‐modulated radiation therapy (IMRT) is complicated by several sources of error, which can cause deviations of optimized plans from the true optimal solution. These errors include the systematic and convergence error, the local minima error, and the optimizer convergence error. We minimize these errors by developing an inverse IMRT treatment planning system with a Monte Carlo based dose engine and a simulated annealing search engine as well as a deterministic search engine. In addition, different generalized equivalent uniform dose (gEUD)‐based and hybrid objective functions were implemented and investigated with simulated annealing. By means of a head‐and‐neck IMRT case we have analyzed the properties of these gEUD‐based objective functions, including its search space and the existence of local optima errors. We found evidence that the use of a previously published investigation of a gEUD‐based objective function results in an uncommon search space with a golf hole structure. This special search space structure leads to trapping in local minima, making it extremely difficult to identify the true global minimum, even when using stochastic search engines. Moreover, for the same IMRT case several local optima have been detected by comparing the solutions of 100 different trials using a gradient optimization algorithm with the global optimum computed by simulated annealing. We have demonstrated that the hybrid objective function, which includes dose‐based objectives for the target and gEUD‐based objectives for normal tissue, results in equally good sparing of the critical structures as for the pure gEUD objective function and lower target dose maxima.
A quality assurance program for image quality of cone‐beam CT guidance in radiation therapy
Authors: Bissonnette Jean‐Pierre , Moseley Douglas J. , Jaffray David A.
Published: May 2008

The clinical introduction of volumetric x‐ray image‐guided radiotherapy systems necessitates formal commissioning of the hardware and image‐guided processes to be used and drafts quality assurance (QA) for both hardware and processes. Satisfying both requirements provides confidence on the system's ability to manage geometric variations in patient setup and internal organ motion. As these systems become a routine clinical modality, the authors present data from their QA program tracking the image quality performance of ten volumetric systems over a period of 3 years. These data are subsequently used to establish evidence‐based tolerances for a QA program. The volumetric imaging systems used in this work combines a linear accelerator with conventional x‐ray tube and an amorphous silicon flat‐panel detector mounted orthogonally from the accelerator central beam axis, in a cone‐beam computed tomography (CBCT) configuration. In the spirit of the AAPM Report No. 74, the present work presents the image quality portion of their QA program; the aspects of the QA protocol addressing imaging geometry have been presented elsewhere. Specifically, the authors are presenting data demonstrating the high linearity of CT numbers, the uniformity of axial reconstructions, and the high contrast spatial resolution of ten CBCT systems (1–2 mm) from two commercial vendors. They are also presenting data accumulated over the period of several months demonstrating the long‐term stability of the flat‐panel detector and of the distances measured on reconstructed volumetric images. Their tests demonstrate that each specific CBCT system has unique performance. In addition, scattered x rays are shown to influence the imaging performance in terms of spatial resolution, axial reconstruction uniformity, and the linearity of CT numbers.
Accelerating protons to therapeutic energies with ultraintense, ultraclean, and ultrashort laser pulses
Authors: Bulanov Stepan S. , Brantov Andrei , Bychenkov Valery Yu. , Chvykov Vladimir , Kalinchenko Galina , Matsuoka Takeshi , Rousseau Pascal , Reed Stephen , Yanovsky Victor , Krushelnick Karl , Litzenberg Dale William , Maksimchuk Anatoly
Published: May 2008

Proton acceleration by high‐intensity laser pulses from ultrathin foils for hadron therapy is discussed. With the improvement of the laser intensity contrast ratio to achieved on the Hercules laser at the University of Michigan, it became possible to attain laser‐solid interactions at intensities up to that allows an efficient regime of laser‐driven ion acceleration from submicron foils. Particle‐in‐cell (PIC) computer simulations of proton acceleration in the directed Coulomb explosion regime from ultrathin double‐layer (heavy ions/light ions) foils of different thicknesses were performed under the anticipated experimental conditions for the Hercules laser with pulse energies from 3 to 15 J, pulse duration of 30 fs at full width half maximum (FWHM), focused to a spot size of (FWHM). In this regime heavy ions expand predominantly in the direction of laser pulse propagation enhancing the longitudinal charge separation electric field that accelerates light ions. The dependence of the maximum proton energy on the foil thickness has been found and the laser pulse characteristics have been matched with the thickness of the target to ensure the most efficient acceleration. Moreover, the proton spectrum demonstrates a peaked structure at high energies, which is required for radiation therapy. Two‐dimensional PIC simulations show that a 150–500 TW laser pulse is able to accelerate protons up to 100–220 MeV energies.
Noise analysis and improvement of displacement vector estimation from angular displacements
Authors: Chen Hao , Varghese Tomy
Published: May 2008

Elastography or elasticity imaging techniques typically image local strains or Young's modulus variations along the insonification direction. Recently, techniques that utilize angular displacement estimates obtained from multiple angular insonification of tissue have been reported. Angular displacement estimates obtained along different angular insonification directions have been utilized for spatial‐angular compounding to reduce noise artifacts in axial‐strain elastograms, and for estimating the axial and lateral components of the displacement vector and the corresponding strain tensors. However, these angular strain estimation techniques were based on the assumption that noise artifacts in the displacement estimates were independent and identically distributed and that the displacement estimates could be modeled using a zero‐mean normal probability density function. Independent and identically distributed random variables refer to a collection of variables that have the same probability distribution and are mutually independent. In this article, a modified least‐squares approach is presented that does not make any assumption regarding the noise in the angular displacement estimates and incorporates displacement noise artifacts into the strain estimation process using a cross‐correlation matrix of the displacement noise artifacts. Two methods for estimating noise artifacts from the displacement images are described. Improvements in the strain tensor (axial and lateral) estimation performance are illustrated utilizing both simulation data obtained using finite‐element analysis and experimental data obtained from a tissue‐mimicking phantom. Improvements in the strain estimation performance are quantified in terms of the elastographic signal‐to‐noise and contrast‐to‐noise ratios obtained with and without the incorporation of the displacement noise artifacts into the least‐squares strain estimator.
Relationship between and stopping‐power ratios for flattening filter free accelerators: A Monte Carlo study
Authors: Xiong Guoming , Rogers D. W. O.
Published: May 2008

The relationship between the photon beam quality specifier and the Spencer–Attix water to air restricted mass collision stopping‐power ratio, , is studied using Monte Carlo simulation with realistic beams in contrast to the previously used realistic but uniform spectra from an isotropic point source. The differences between accelerators with and without flattening filters are investigated since flattening filter free accelerators appear to be useful for IMRT. Our results show that the standard relationship between and , which is used in the TG–51 protocol to calculate the quality conversion factor , is acceptable for beams with or without a flattening filter with a maximum error of 0.4%, although a fit to the new data would reduce the maximum error to 0.2%. Reasons for differences between the individual values of and with and without a flattening filter are studied. Specifically the differences due to the softening of the beam, the change in shape of the profile, and the inclusion of radial variations in the photon energy spectra, are investigated. It is shown that if is used as a beam quality specifier, there are two different relationships between and which differ by 0.4%–1%. When using as a beam quality specifier in a beam without a flattening filter, one should subtract 0.5% from the value of for a given value of .
Energy spectra, sources, and shielding considerations for neutrons generated by a flattening filter‐free Clinac
Authors: Kry Stephen F. , Howell Rebecca M. , Titt Uwe , Salehpour Mohammad , Mohan Radhe , Vassiliev Oleg N.
Published: May 2008

Neutron production is an unwanted result of high‐energy radiation therapy and results in secondary exposure of patients and radiation therapists to radiation. Recent studies have shown that delivering therapy using a standard medical accelerator with the flattening filter removed may reduce neutron fluence by nearly 70% over the course of prostate intensity‐modulated radiation therapy (IMRT). In the current study, the Bonner sphere technique was used to compare the neutron spectrum produced when the filter is present and when it is absent. In addition, the following was calculated: (1) the neutron‐shielding parameters of source strength and ambient dose equivalent and (2) using the Monte Carlo technique, the sources of neutron production in the accelerator head. It was found that the neutron spectrum was nearly constant, regardless of the presence of the flattening filter; however, the total fluence and ambient dose equivalent over the course of prostate IMRT were more than 70% lower when the filter was removed. Similarly, shielding parameters were lower when the filter was removed. Finally, the primary collimator and jaws accounted for the majority of neutron production, both with and without the flattening filter; however, with the flattening filter removed, the upper jaw accounted for much more neutron production relative to when the filter was present. Ultimately, removal of the flattening filter may offer several clinical advantages, including a reduction in the dose from neutrons to the patient and to radiation personnel.
Improved activity estimation with MC‐JOSEM versus TEW‐JOSEM in SPECT
Authors: Ouyang Jinsong , Fakhri Georges El , Moore Stephen C.
Published: May 2008

We have previously developed a fast Monte Carlo (MC)‐based joint ordered‐subset expectation maximization (JOSEM) iterative reconstruction algorithm, MC‐JOSEM. A phantom study was performed to compare quantitative imaging performance of MC‐JOSEM with that of a triple‐energy‐window approach (TEW) in which estimated scatter was also included additively within JOSEM, TEW‐JOSEM. We acquired high‐count projections of a sphere of at different locations in the water‐filled torso phantom; high‐count projections were then obtained with only in the liver or only in the soft‐tissue background compartment, so that we could generate synthetic projections for spheres surrounded by various activity distributions. MC scatter estimates used by MC‐JOSEM were computed once after five iterations of TEW‐JOSEM. Images of different combinations of liver/background and sphere/background activity concentration ratios were reconstructed by both TEW‐JOSEM and MC‐JOSEM for 40 iterations. For activity estimation in the sphere, MC‐JOSEM always produced better relative bias and relative standard deviation than TEW‐JOSEM for each sphere location, iteration number, and activity combination. The average relative bias of activity estimates in the sphere for MC‐JOSEM after 40 iterations was , versus for TEW‐JOSEM, while the average relative standard deviation of the sphere activity estimates was 16.1% for MC‐JOSEM, versus 27.4% for TEW‐JOSEM. Additionally, the average relative bias of activity concentration estimates in the liver and the background for MC‐JOSEM after 40 iterations was , versus for TEW‐JOSEM, while the average relative standard deviation of these estimates was 2.5% for MC‐JOSEM, versus 3.4% for TEW‐JOSEM. MC‐JOSEM is a promising approach for quantitative activity estimation in SPECT.
Dosimetric and anatomic indicators of late rectal toxicity after high‐dose intensity modulated radiation therapy for prostate cancer
Authors: Munbodh Reshma , Jackson Andrew , Bauer Joseph , Schmidtlein C. Ross , Zelefsky Michael J.
Published: May 2008

We seek to identify dosimetric and anatomic indicators of late rectal toxicity in prostate cancer patients treated with intensity modulated radiation therapy (IMRT). Data from 49 patients sampled from 698 patients treated for clinically localized prostate cancer at the Memorial Sloan‐Kettering Cancer Center with IMRT to a dose of were analyzed. The end point of the study was late Grade 2 or worse rectal toxicity within 30 months of treatment. Dosimetric analysis was performed on the rectum surface in three dimensions and on two‐dimensional dose maps obtained by flattening the rectum surface using a conformal mapping procedure. Several parameters including the percentage and absolute surface area of the rectum irradiated, mean dose as a function of location on the rectum, planning target volume (PTV) size and rectum size were analyzed for correlation to toxicity. Significance was set at for a two‐sided ‐test. Correlation between absolute areas irradiated and toxicity was observed on both the rectum surface and flattened rectum. Patients with toxicity also received a significantly higher mean dose to the superior 25% of the rectum surface and 15% of the flattened rectum. PTV volume, PTV height, rectum surface area and average cross‐sectional area were significantly larger in patients with toxicity. The conformal mapping procedure has potential utility for evaluating dose to the rectum and risk of toxicity. Late rectal toxicity was related to the irradiation of the upper part of the rectum and also to the absolute area irradiated, PTV size, and rectum size on the planning computed tomography (CT) scan.
Molecular Survey of β-Lactamases Conferring Resistance to Newer β-Lactams in
Enterobacteriaceae
Isolates from Polish Hospitals
Authors: Empel Joanna , Baraniak Anna , Literacka Elżbieta , Mrówka Agnieszka , Fiett Janusz , Sadowy Ewa , Hryniewicz Waleria , Gniadkowski Marek
Published: May 2008

The first national survey of resistance to newer β-lactams in nosocomial populations of
Enterobacteriaceae
in Poland was performed. The study covered all nonrepetitive enterobacterial isolates cultured from specimens from inpatients in 13 regional secondary-care hospitals from November 2003 to January 2004. Among 2,388 isolates, the predominant species was
Escherichia coli
(59.6%), followed by
Proteus mirabilis
(14.5%) and
Klebsiella
spp. (8.5%). The frequency of extended-spectrum β-lactamases (ESBLs) was very high, with ESBLs present in 11.1% of all isolates and 40.4% of
Klebsiella pneumoniae
isolates, the latter value greatly exceeding that for
E. coli
(2.5%). The contribution of outbreak isolates was significant, resulting, for example, in a particularly high rate of ESBL producers among
Serratia marcescens
isolates (70.8%). The pool of ESBL types was overwhelmingly dominated (81.7%) by CTX-M-like β-lactamases CTX-M-3 (80.6%) and CTX-M-15, with SHV types (17.5%; SHV-2, SHV-5, and SHV-12) and sporadic TEM-like enzymes (0.7%; TEM-19 and TEM-48) being the next most frequent. Acquired AmpC-type cephalosporinases were observed exclusively in
P. mirabilis
, in 20.5% of the isolates of this species (compared with the frequency of ESBL producers of 11.5% of
P. mirabilis
isolates). All these cephalosporinases (CMY-12, CMY-15, and a novel variant, CMY-38) originated from
Citrobacter freundii
. Four isolates of
E. coli
(two isolates),
K. pneumoniae
(one isolate), and
P. mirabilis
(one isolate) produced class A inhibitor-resistant β-lactamases (TEM-30, TEM-32, TEM-37, and SHV-49), being the first of such producers identified in Poland. The survey documented both specific and more global characteristics of the epidemiology of the β-lactamase-mediated resistance in enterobacteria from Polish hospitals and demonstrated that the ESBL frequency has reached an alarming level.
Chemical Target Validation Studies of Aminopeptidase in Malaria Parasites Using α-Aminoalkylphosphonate and Phosphonopeptide Inhibitors
Authors: Cunningham Eithne , Drag Marcin , Kafarski Pawel , Bell Angus
Published: May 2008

During its intraerythrocytic phase, the most lethal human malarial parasite,
Plasmodium falciparum
, digests host cell hemoglobin as a source of some of the amino acids required for its own protein synthesis. A number of parasite endopeptidases (including plasmepsins and falcipains) process the globin into small peptides. These peptides appear to be further digested to free amino acids by aminopeptidases, enzymes that catalyze the sequential cleavage of N-terminal amino acids from peptides. Aminopeptidases are classified into different evolutionary families according to their sequence motifs and preferred substrates. The aminopeptidase inhibitor bestatin can disrupt parasite development, suggesting that this group of enzymes might be a chemotherapeutic target. Two bestatin-susceptible aminopeptidase activities, associated with gene products belonging to the M1 and M17 families, have been described in blood-stage
P. falciparum
parasites, but it is not known whether one or both are required for parasite development. To establish whether inhibition of the M17 aminopeptidase is sufficient to confer antimalarial activity, we evaluated 35 aminoalkylphosphonate and phosphonopeptide compounds designed to be specific inhibitors of M17 aminopeptidases. The compounds had a range of activities against cultured
P. falciparum
parasites with 50% inhibitory concentrations down to 14 μM. Some of the compounds were also potent inhibitors of parasite aminopeptidase activity, though it appeared that many were capable of inhibiting the M1 as well as the M17 enzyme. There was a strong correlation between the potencies of the compounds against whole parasites and against the enzyme, suggesting that M17 and/or M1 aminopeptidases may be valid antimalarial drug targets.
Analyses of microfungal diversity from a user's perspective
Authors: Bills Gerald F.
Published: May 2008

For microfungi, the understanding of the extent of their biotic diversity and of their ecological function remains underdeveloped. An insufficient number of specialists are available to collect and document the world's microfungi. Organizations that exploit microfungi as a source of chemical products or for biotechnological applications also may need to assess microfungal diversity to meet their specific objectives. During future inventories of biomes that are deemed of high biological interest or that may harbor species of commercial potential, methods for enumerating microfungi must be made more efficient, and fungal communities should be evaluated in such a way as to extract the maximum information. Rapid isolation techniques can be used to deliver high species diversity and obtain quantitative estimates of fungal species diversity and abundance. These methods, some previously developed by soil ecologists, rely heavily on selective media, dissection, physical and chemical elimination of contaminants, knowledge of spore behavior, and manipulation of incubation conditions. The rapid expansion of our knowledge of endophytes in woody plants exemplifies the success of this approach. Whenever rigorous isolation strategies have been applied to unstudied substrates, an unrealized depth of species diversity has been revealed. When methods are standardized, richness of different fungal communities, geographic variation within communities, or effectiveness of isolation procedures can be quickly and quantitatively compared. Exploration of complex substrata via indirect isolation expands the view of the fungal community in a way that complements traditional mycological collecting. However, fungi isolated into culture are often impossible to identify based on morphology. The utility of the rapid isolation approach to the inventory problem is illustrated with experiences with microfungi from rain-forest leaf litter.Key words: fungal metabolites, industrial microbiology, microbial diversity, natural products.
Ecological considerations for the use of the nematophagous fungus, Verticillium chlamydosporium, to control plant parasitic nematodes
Authors: Kerry B. R.
Published: May 2008

The nematophagous fungus, Verticillium chlamydosporium, has considerable potential as a biological control agent for root-knot nematodes on a range of crops. The fungus is a general facultative parasite that attacks the eggs of several nematode species. The biology of the fungus is reviewed and the need for a detailed understanding of its ecology for its rational use as a biological control agent is highlighted. Isolates of the fungus must colonize the rhizosphere to be effective control agents. Plants differ in their ability to support the fungus and greatest control is achieved on those cultivars that support abundant growth of the fungus but produce only limited galling in response to nematode attack. On such plants, most eggs produced by nematodes are exposed to parasitism by this nematophagous fungus in the rhizosphere. Key words: biological control, nematophagous fungi, root-knot nematodes, Verticillium chlamydosporium.
Constraints associated with taxonomy of biocontrol fungi
Authors: Samson Robert A.
Published: May 2008

An increasing number of fungi are being collected and screened for the biological control of pests, but nomenclature, taxonomy, and correct identification of many of them remain problematic. Trichoderma spp. and the rust fungi are promising candidates for biocontrol agents, yet they present serious taxonomic problems. Several groups of entomopathogenic fungi are also potential biocontrol sources of agents. Genera such as Cordyceps, Aschersonia, Verticillium, Beauveria, and Metarhizium are in need of urgent revision. Before their release can be considered, all details of their complex life cycles and taxonomy have to be elucidated to satisfy quarantine authorities. Formerly, the taxonomy and identification of biocontrol fungi has been based largely on morphological structures, but molecular techniques have been introduced to provide more objective criteria. Beauveria and Metarhizium spp. have been subjected to several molecular techniques that have resolved phylogeny and species concepts. In Metarhizium, a high degree of genetic diversity is present. Incorrect typification, lack of holotypes, and poorly resolved life cycles and unclear teleomorph – (syn)anamorph connections are serious taxonomic contraints. Only a small fraction of the fungi that can be used for biological control has been examined. The destruction of habitats and ecosystems for these fungi will result in the disappearance of fungal germ plasm of potential value, not only for biological control but also as a source of novel metabolites. This loss and the decline of taxonomic expertise in the fungi are major problems. Key words: biocontrol, taxonomy, Trichoderma, Beauveria, Metarhizium, Cordyceps.
Global regulation of sulfur assimilation in Neurospora
Authors: Marzluf George A. , Li Qunhui , Coulter Kristin
Published: May 2008

A complex regulatory circuit controls expression of many permeases and enzymes involved in sulfur assimilation in the filamentous fungus Neurospora crassa. CYS3, the global positive-acting sulfur regulatory protein, turns on the expression of structural genes that encode sulfur enzymes when N. crassa cells are limited for sulfur. Expression of the cys-3 gene itself is highly regulated by negative-acting sulfur-controller scon genes and by autogenous regulation. The CYS3 protein is localized within the nucleus and contains a bZip DNA-binding motif and regions rich in alanine and in proline that appear to function in trans activation. Amino acid substitutions for basic or neutral amino acids in the bZip domain of CYS3 lead to significant changes in its DNA-binding activity. Key words: sulfur regulation, CYS3, autogenous control, leucine zipper, trans activation.
Mating type inNeurosporaand closely related ascomycetes: some current problems
Authors: Metzenberg Robert L. , Randall Thomas A.
Published: May 2008

Neurospora crassa and related ascomycetes such as Podospora anserina exist in two mating types, encoded in a unique region of one chromosome. Classical genetic analysis outlined the nature of the questions and provided important materials for further work. In the mating type region, there is little DNA sequence resemblance between the two mating types. They are, therefore, called idiomorphs rather than alleles. There are no silent copies of these sequences in the genome, so mating type switching is impossible. Cloning, sequence analysis, and complementation studies involving these idiomorphs has begun to shed light on their function. One of the idiomorphs contains three reading frames; one is essential for fertilization and fruiting body formation and the other two are involved in post-fertilization functions including ascus and ascospore formation. In various species of the genus Neurospora, the centromere-proximal flank of the idiomorphs is highly variable in DNA sequence among species, and in some cases, between mating types. The similarities and differences in these flanking sequences allow some conclusions to be drawn about the possible phylogenetic relationship of these species. Key words: Neurospora, ascomycetes, mating, evolution, compatibility, HMG proteins.
Analysis of cell cycle regulation usingAspergillus nidulans
Authors: Ye Xiang S. , Xu Gang , Pu Robert T. , Fincher Russell R. , Osmani Aysha H. , Osmani Stephen A.
Published: May 2008

Aspergillus nidulans has proved to be an excellent model system to help unravel the genetic and biochemical control systems that regulate the cell cycle. Many genes that specifically affect progression through G2 into mitosis have been isolated. Study of these genes has helped to formulate concepts about how the cell cycle is regulated. The existence of regulatory networks involving protein phosphorylation and dephosphorylation has been realized, and how the kinases and phosphatases of these networks ensure correct order and timing through the cell cycle is beginning to be understood. Our studies indicate that activation of two protein kinases is essential for progression into mitosis. One, the universal p34cdc2H1 kinase, has been well studied in many systems and is considered the key activator of mitotic initiation. However, in the absence of the NIMA protein kinase p34cdc2cannot promote mitosis. How these two mitotic kinases interact is therefore of great importance to our understanding of cell cycle regulation. The contribution of studies using A. nidulans to the formulation of concepts about how the cell cycle is regulated is the topic of this paper. Key words: Aspergillus nidulans, cell cycle regulation, protein kinase, NIMA, p34cdc2, cyclinB, Cdc25.
Analysis of differentiation and development of the specialized infection structures formed by biotrophic fungal plant pathogens using monoclonal antibodies
Authors: Green Jonathan R. , Pain Naomi A. , Cannell Martin E. , Leckie Calum P. , McCready Sharon , Mitchell Alison J. , Callow James A. , Jones Gwyneth L. , O'Connell Richard J. , Mendgen Kurt
Published: May 2008

Monoclonal antibodies have been used to study the differentiation and development of the specialized infection structures formed in the Colletotrichum–bean and powdery mildew – pea interactions. In the Colletotrichum lindemuthianum – bean interaction, monoclonal antibodies have been used to show that the extracellular matrices associated with conidia, germ tubes, and appressoria differ in composition and that the extracellular glycoproteins are organized into specific regions of the fungal cell surface. Monoclonal antibody UB27 has been used to show that the plasma membrane of appressoria is differentiated into distinct domains, with the integral membrane glycoprotein identified by UB27 being excluded from the pore region. UB25 recognizes a glycoprotein located specifically in the cell wall/matrix of intracellular hyphae and is expressed only during the biotrophic phase of development. In the Erysiphe pisi – pea interaction, UB8 and UB10 identify glycoproteins specific to the haustorial plasma membrane within the haustorial complex. Monoclonal antibodies that recognize the extrahaustorial membrane have shown that this membrane contains specific components, as well as glycoproteins in common with the host plasma membrane. UB8 has been successfully used to isolate a gene sequence coding for the protein antigen, by immunoscreening a cDNA expression library prepared from infected epidermis. An antibody that recognizes the plant endoplasmic reticulum has been used to show that this structure reorganizes around the developing haustorial complex in pea epidermal cells. Key words: appressorium, biotrophy, Colletotrichum lindemuthianum, Erysiphe pisi, haustorium, monoclonal antibody, powdery mildew.
Microinjection of fungal cells: a powerful experimental technique
Authors: Jackson Sandra L.
Published: May 2008

Microinjection is an effective method for introducing membrane-impermeant molecules into cells. As yet however, mycologists have made only limited use of this technique. Recent improvements in both equipment and methodology may change this situation as it is now possible to routinely microinject small turgid cells. In this paper I will review microinjection techniques and evaluate these with regard to fungal cells. The potential of microinjection for furthering our knowledge of fungal biology will be discussed. Key words: microinjection, fungi, oomycetes, F-actin, calcium.