cssi/SciSciGPT-SciSciNet huggingface dataset:
Computer Simulation of Speckle in a Synthetic Aperture Radar Image Pixel

Images of a uniform scene produced with a synthetic aperture radar will frequently appear nonuniform. This phenomenon, called ?speckle,? is attributed to the coherency of the radar signal and intrapixel interferometry. Speckle is generally regarded as image contrast or response variation between adjacent pixels of a uniform scene. The same type of variation can be observed by imaging just one such pixel when viewed from different azimuthal heading angles. A computer program described in this paper was written to simulate the radar return from a single pixel containing numerous scatterers. The phase and amplitude of the signal reflected from the pixel generally varies from pulse to pulse due to intrapixel interference. After integration, the pixel response usually differs with each ?azimuth look,? and this speckle variation between azimuth looks may be as much as 20 dB or more. Speckle variation can be significantly reduced by averaging or median filtering multiple azimuth looks per pixel.
Susceptibility of different strains of influenza a virus to the inhibitory effects of 2-deoxy-2,3-dehydro-N-trifluoroacetylneuraminic acid (FANA)

Abstract Susceptibility to the neuraminidase-inhibiting effects of a synthetic analog of neuraminic acid, 2-deoxy-2,3-dehydro- N -trifluoroacetylneuraminic acid (FANA) was found to vary among different strains of influenza A virus according to the neuraminidase they contain. In particular, NWS (H0N1) virus and recombinant strains which derive their neuraminidase from NWS are especially susceptible to FANA as measured by the concentrations of inhibitor which reduce rates of elution from red cells, in vitro neuraminidase activity using fetuin as a substrate, and virus replication in cell culture under agar. Growth in tissue culture of X-7 (H0N2) virus and all recombinant viruses containing N2 neuraminidase is approximately 50–200 times less susceptible to inhibition by FANA. These results provide further evidence that the inhibitory effects of FANA on the replication of influenza viruses are mediated by its specific neuraminidase-inhibitory activity and confirm that neuraminidase activity is necessary for the replication of influenza viruses.
Prozessflexibilisierung im Dienstleistungssektor

Dienstleister stehen mehr denn je unter Druck, da sie in der Lage sein mussen, flexibel auf sich verandernde Umweltbedingungen reagieren zu konnen. Dies erfordert Prozessflexibilitat. Typische Bedarfstreiber sind z. B. schwankende Nachfragemengen, Anderungen in der Leistungserbringung oder Anderungen bei den eingebundenen Partnern. Auf diese kann mit Masnahmen zur Flexibilitatssteigerung wie Automatisierung, Zeitarbeit, Multi-Skilling, Alternativen im Prozessmodell, Unterspezifikation, Modularisierung oder Multi-Sourcing reagiert werden. Anhand konkreter Beispiele aus Interviews mit Entscheidungstragern aus einem Telekommunikations- und einem Versicherungsunternehmen werden Erfahrungen und Lessons Learned aus der Praxis aufgezeigt.
Noise-induced speed up in repetitively firing neurons occurs far from spike threshold

Injecting white noise currents has been shown to increase mean firing rate in several types of neuron. This speed up is generally attributed to the fact that depolarizing currents on the tails of the noise distribution push cells past spike threshold sooner than they would have otherwise. As part of a larger effort to understand the dynamic properties of rat subthalamic (STN) neurons, we have performed perforated patch recordings of these tonically active neurons in brain slices, exposing them to contiguous sequences of brief current pulses drawn from a Gaussian distribution. Pulsed noise disrupted firing pattern with no significant change in rate over a wide range of noise amplitudes, so long as the pulse durations were brief (<2 ms). With longer pulse durations, neurons increased their firing rate with noise, with greater increases for pulses of larger magnitude and longer duration. However, individual neurons displayed varying degrees of noise-induced speed up. We used phase resetting methods to understand the noise-induced changes in the mean and variance of the recorded interspike interval distributions. For each cell, a phase response curves (PRC) was derived by using linear interpolation to estimate the phase of the neuron between spikes, followed by a linear regression to estimate the sensitivity of the cell to input perturbations at each phase. We then compared Monte Carlo simulations of a one-dimensional phase model to predict the response patterns of individual neurons. Surprisingly, simulation results produced a good match to experimental mean and variances even at noise levels leading to autocorrelation histograms with no visible periodicity (CVs ~ 0.4). We then investigated simulations results in detail to understand the dynamic mechanism that underlies the noise-induced speed up in these neurons. Plots of the mean phase as a function of time revealed that the noise-induced phase advance occurred early in an interspike interval, well before trajectories approach the time of the next spike. This phase advance can be understood as ‘noise-induced drift’ in the Stratanovich interpretation of stochastic differential equations, with possible supralinear contributions for pulses of finite duration. Current research uses artificially constructed PRCs to examine how the increasing spread of the phase distribution during each intervals leads to an asymmetric sampling of the noise-induced drift, preventing the early noise-induced speed up from being canceled by an expected noise-induced slowing as the PRC approaches zero near the time of the next spike.
Lexical access via letter naming in a profoundly alexic and anomic patient: a treatment study.

We report the results of a letter naming treatment designed to facilitate letter-by-letter reading in an aphasic patient with no reading ability. Patient M.R.'s anomia for written letters reflected two loci of impairment within visual naming: impaired letter activation from print (a deficit commonly seen in pure alexic patients who read letter by letter) and impaired access to phonology via semantics (documented in a severe multimodality anomia). Remarkably, M.R. retained an excellent ability to pronounce orally spelled words, demonstrating that abstract letter identities could be activated normally via spoken letter names, and also that lexical phonological representations were intact when accessed via spoken letter names. M.R.'s training in oral naming of written letters resulted in significant improvement in her oral naming of trained letters. Importantly, as M.R.'s letter naming improved, she became able to employ letter-by-letter reading as a compensatory strategy for oral word reading. M.R.'s success in letter naming and letter-by-letter reading suggests that other patients with a similar pattern of spared and impaired cognitive abilities may benefit from a similar treatment. Moreover, this study highlights the value of testing the pronunciation of orally spelled words in localizing the source of prelexical reading impairment and in predicting the functional outcome of treatment for impaired letter activation in reading.
Impact of colonoscopy preparation quality on detection of suspected colonic neoplasia

Abstract Background: Suboptimal bowel preparation for colonoscopy can lead to missed colonic lesions. The aim of this study was to describe the impact of preparation quality on detection of suspected colonic neoplasia. Methods: Data from the Clinical Outcomes Research Initiative national endoscopic database for the period January 1, 2000 to December 31, 2001, were analyzed. Patient demographics, quality of preparation, and colonoscopy findings were abstracted from the database. Results: Overall, 93,004 colonoscopies with adequate documentation were reviewed. Preparation was adequate for 71,501 (76.9%) of these procedures. On multivariate analysis, preparation adequacy was associated with colonic lesion detection, odds ratio (OR) 1.21: 95% CI [1.16, 1.25]. Adequate preparation demonstrated a closer association with identification of "nonsignificant" lesions (polyps ≤9 mm), OR 1.23: 95% CI [1.19, 1.28], compared with "significant" lesion detection (mass lesion, polyps >9 mm), OR 1.05: 95% CI [0.98, 1.11]. Conclusions: Bowel preparation is inadequate for almost a quarter of patients undergoing colonoscopy. These results suggest that inadequate preparation quality only hinders detection of smaller lesions, while having negligible impact on detection of larger lesions. These results should be confirmed in prospective studies. (Gastrointest Endosc 2003;58:76-9.)
Financial impact of a resident-run vascular and interventional radiology clinic

Learning Objectives Resident-run Vascular and Interventional Radiology (VIR) resident clinics represent an emerging trend in the education of VIR trainees. As the concept is not widely adopted, the financial impact of a clinic on an existing training program has not been described. We present data regarding reimbursement over a three-year period at a resident-run VIR clinic at a single institution. We detail reimbursement patterns of the training institution and the private practice group staffing the VIR section. Background The Maine Medical Center Model and referral patterns of a resident-run VIR clinic has been presented previously. We believe the clinical access offered by direct patient care from referral through follow-up provides a means to maintain clinical competence. A clinic fosters the development of patient care skills specific to VIR and provides correlative experience relevant to VIR imaging. The clinic serves to improve access for patients with limited financial resources. Clinical Findings/Procedure Details The first 40 clinic referrals generated 34 consult visits with a total of 56 clinic visits. Consults generated 36 imaging studies and 31 unique procedures. Total professional charges for the VIR physician group were $126,642. Nearly half was categorized as free care ($58,333) under identical criteria for the hospital and radiology group. Of the remaining charges, 23.8% ($16,291, or 12.9% of total charges) were reimbursed. Total charges generated by Maine Medical Center were $347,264. Of available data, approximately 30.5% was reimbursed. Medicare and Medicaid (Maine Care) accounted for the majority of reimbursement. Conclusion and/or Teaching Points A resident-run VIR clinic represents an exceptional opportunity for trainees to build the clinical skills necessary for contemporary practice. With the introduction of the dual certificate training pathway, we expect that resident clinics will be explored at more institutions. Patients served within the institutional clinic environment traditionally have limited financial resources, and reimbursement is expected to be minimal. Our reimbursement data serves as a realistic benchmark for programs that wish to develop similar clinics at other training institutions.
Metabolic activation of chemical carcinogens by kidney from rats and mice of various ages

1. The ability of homogenates from kidney tissue of 4- to 26-month-old male Fischer F344 rats, 6- to 30-month-old male Sprague-Dawley rats, and 5- to 30-month-old male C57 BL/6J mice to metabolically activate the chemical procarcinogens 2-aminofluorene and aflatoxin B1 to mutagens was measured using the Ames Salmonella/microsome test. 2. The conversion of 2-aminofluorene to mutagenic compounds by kidney homogenates from Fischer F344 and Sprague-Dawley rats and C57 BL/6J mice decreased 35-50% with increasing age. 3. An age-related decrease (50-65%) in the ability of kidney homogenates from Fischer F344 rats and C57 BL/6J mice to convert aflatoxin B1 to mutagenic compounds was also observed.
Analysis of numerical instability in single-stage gas permeation

A single-stage co-current gas permeation process with two permeable components and one non-permeable component is modeled with a sweep gas in the permeation side. The introduction of sweep gas in the permeate side give rise to a singular point in the resulting differential equations. To solve the model equations for a wide range of stage cuts, one need to avoid this singular point because the system becomes unstable, resulting in floating-point error. Present work analyzes this instability from different points of view and a method is proposed to overcome this instability with some examples.
Maintaining reality: Relational agents for antipsychotic medication adherence

We describe an animated, conversational computer agent designed to promote antipsychotic medication adherence among patients with schizophrenia. In addition to medication adherence, the agent also promotes physical activity and system usage, and includes verbal and nonverbal behavior designed to foster a therapeutic alliance with patients. We discuss special considerations in designing interventions for this patient population, and challenges in developing and evaluating conversational agents in the mental health domain. Results from a pilot evaluation study of the agent indicate that it is accepted and effective.
Psychology versus anthropology in drug use studies: The representative case method

James V. Spotts and Franklin C. Shontz. Cocaine Users: A Representative Case Approach. New York: The Free Press, 1980. x + 517 pp. Tables, Index. $ 19.91, cloth.
Synthesis of p-nitrophenyl β-glycosides of (1→6)-β-d-galactopyranosyl-oligosaccharides☆

Abstract Sequential tritylation, benzoylation, and detritylation of p -nitrophenyl β- d -galactopyranoside gave p -nitrophenyl 2,3,4-tri- O -benzoyl-β- d -galactopyranoside ( 2 ). Reaction of 2 with 2,3,4,6-tetra- O -benzoyl-α- d -galactopyranosyl bromide gave p -nitrophenyl O -(2,3,4,6-tetra- O -benzoyl-β- d -galactopyranosyl)-(1→6)-2,3,4-tri- O -benzoyl-β- d -galactopyranoside ( 4 ) in 94% yield. Deprotection with sodium methoxide then gave the crystalline p -nitrophenyl O -(β- d -galactopyranosyl)-(1→6)-β- d -galactopyranoside ( 5 ). Condensation of 2 with 2,3,4-tri- O -benzoyl-6- O -bromoacetyl-α- d -galactopyranosyl bromide ( 3 ) readily yielded the protected disaccharide p -nitrophenyl O -(2,3,4-tri- O -benzoyl-6- O -bromoacetyl-β- d -galactopyranosyl)-(1→6)-2,3,4-tri- O -benzoyl-β- d -galactopyranoside ( 6 ) from which the bromoacetyl groups could be selectively removed. Condensation of the resulting material with tetra- O -benzoyl-α- d -galactopyranosyl bromide then yielded p -nitrophenyl O -(2,3,4,6-tetra- O -benzoyl-β- d -galactopyranosyl)-(1→6)- O -(2,3,4-tri- O -benzoyl-β- d -galactopyranosyl)-(1→6)-2,3,4-tri- O -benzoyl-β- d -galactopyranoside, ( 8 ), which was converted into the crystalline trisaccharide p -nitrophenyl O -(β- d -galactopyranosyl)-(1→6)- O -β- d -galactopyranosyl)-(1→6)-β- d -galactopyranoside ( 9 ) by treatment with sodium methoxide. Preliminary experiments on the interaction of p -(bromoacetamido)phenyl and p -isothiocyanatophenyl glycoside derivatives of some of these galacto-saccharides with monoclonal anti-(1→6)-β- d -galactopyranan antibodies have been conducted.
Neonatal sepsis and death caused by resistant Escherichia coli: Possible consequences of extended maternal ampicillin administration

Abstract Objective: Our goal was to evaluate the relationship between neonatal death caused by sepsis associated with ampicillin-resistant organisms and length of antibiotic exposure. Study Design: All neonatal deaths from culture-positive sepsis over a 3-year period were examined. Infants who were delivered at either the University of Mississippi Medical Center or at Saint Barnabas Medical Center at ≥24 weeks' gestation and died within 7 days of life were included. Information on the organism causing sepsis and its sensitivities was collected, and the number of doses of ampicillin administered to the mother before delivery was determined. Results: Of the 78 neonatal deaths, 35 met the inclusion criteria. There were 8 cases of sepsis from ampicillin-resistant Escherichia coli and 27 cases caused by other organisms. There was a statistically significant difference between the mean number of doses of ampicillin received by the ampicillin-resistant Escherichia coli group (17.6 ± 5.5) compared with the other organisms group (4.9 ± 3.6) ( P Conclusion: A relationship exists between neonatal death caused by ampicillin-resistant Escherichia coli and prolonged antepartum exposure to ampicillin. (Am J Obstet Gynecol 1999;180:1345-8.)
Modern shoreface and inner-shelf storm deposits off the East Texas Coast, Gulf of Mexico

ABSTRACT The modern shoreface and inner-shelf sediments off the east Texas coast on the Gulf of Mexico were examined using sediment cores and high-resolution seismic data. Low sediment input and low effective accommodation space resulted in the overall thinness of the modern marine sediment cover in the region. Erosion on the inner shelf during historic ( 100 yr) times produced patches of sand in a predominantly mud-dominated environment. Storm beds are scarce on the inner shelf. The shoreface succession off Galveston Island is characterized by offshore-directed crosscutting storm channels of varying sizes. The existence of these channels and the relatively high frequency of storms and hurricanes that have affected the region during historical imes are inconsistent with the paucity of storm deposits on the inner shelf. The offshore-directed channelized flows may have been prevented from going beyond the shoreface by strong along-shelf storm currents that impinged on the shoreface. In contrast to the storm record on the east Texas shelf, the central Texas shelf shows a greater frequency of and more laterally persistent storm sand beds due to greater effective accommodation space and higher sediment supply there.
Optical Laboratory Realization Of Symbolic Substitution

Optical symbolic substitution offers general purpose optical processors for numeric, logic, and image processing functions. Its realization on an optical correlator is most attractive. This paper addresses the optical laboratory realization of the symbolic substitution steps of recognition and substitution with attention to the effects of the beam balance ratio (K-ratio) used when synthesizing the matched spatial filters for a symbolic substitution correlator. Specifically, low spatial frequencies should be emphasized in the substitution step and high spatial frequencies should be emphasized in the recognition step.
A Study of Lifting Rotor Flapping Response Peak Distribution in Atmospheric Turbulence

Studies are made of the peak statistics of rigid-blade flapping responses to atmospheric turbulence at high advance ratios. The rotor model is characterized by a finite dimensional linear system with periodically varying parameters and with feedback controls. System inputs represent a modulated nonstationary Gaussian process. The response description includes: 1) the ratio between the total number of peaks and of zero-level up-crossings per period, 2) the ranges of lower level thresholds within which the response process could deviate from being a narrow-band process, and 3) the accuracy of the approximate formulae of peak distribution conditional on the occurrence of a peak. The conditional probability density of peak magnitude indicates that high-level peaks which cause significant damage to system components are most likely to occur within narrow ranges of the azimuth angle. The Rayleigh density law provides a satisfactory approximation to this conditional prpbability density only within such narrow azimuth ranges. A similar approximation by a widely used narrow-band formula is not satisfactory. Numerical analysis further substantiates an earlier finding that the flapping response is a quasi-coherent narrow-band process with small phase angle variance.
Riemann-Stieltjes quasi-martingale integration☆

Abstract Stochastic integration of left continuous integrands with respect to quasimartingales is developed as the pathwise limit of Riemann-Stieltjes sums. The procedure is extended to right continuous integrands.
Practice style in the nursing home: dimensions for assessment and quality improvement

Objective Based on research staff observations during several studies in nursing homes and the findings of other studies, we propose a nomenclature of components of care for the elderly in nursing homes. The paper seeks thereby to operationalize those aspects of the nursing home practice style that can be improved. Methods This operationalization examines two main components (staff and institutional components) of practice style of care in nursing homes. Four domains characterize staff conduct (knowledge, practice style proficiency, flexibility and individualization of care and communication) and three domains define institutional conduct (staff support, resources and flexibility/rigidity of policies). Results The paper addresses critical aspects of staff conduct, and by extension, key features that require training, monitoring, and systemic change. Examples for each domain of practice style are provided. Conclusions After systematically reviewing the observations and findings it was concluded that enhancing practice styles in the nursing home requires knowledge, communication, flexibility, understanding, and genuine concern on the part of nursing home staff and administrators at all levels. We acknowledge and understand, of course, that changing practice styles in nursing homes is a difficult and time-consuming process. Copyright © 2007 John Wiley & Sons, Ltd.
Issue Salience, News Coverage, and Attention Cycles of Environmental Problems

Applying Downs' theoretical perspective and analytical approach, the “issue-attention cycles” of “second generation” environmental problems are evaluated using network news coverage and public opinion on environmental problems from 1975 to 1990. Previous research is improved upon and extended by using actual network news coverage of second generation environmental issues (toxic, hazardous, nuclear, and solid waste management, contamination, and accidents) to track these problems through all five stages of Downs' construct of the issue-attention cycle (his analysis ventured through only two stages completely). Findings show that Downs' conceptualization of the issue-attention cycle, although useful, is problematic. The cyclical nature of the proposed model is evident based on network news coverage. The pattern observed for public opinion, however, is not exactly cyclical; there is evidence of a relationship between network news information and public opinion, which corroborates past research and further refines our understanding of the interaction of media, public opinion, and public policy.
Stent-graft treatment for bleeding from a presumed aortoenteric fistula.

Purpose:To describe a technique for the endovascular treatment of aortoenteric fistula.Methods and Results:A 67-year-old man who had undergone aortobi-iliac grafting for aneurysmal disease 8 years previously presented with life-threatening upper gastrointestinal hemorrhage. Endoscopy after resuscitation did not identify the source of the bleeding. Computed tomographic (CT) scanning and angiography revealed pseudoaneurysm formation at the upper anastomosis 1 cm below the renal arteries. Measurements were taken for endovascular repair. Uncomplicated emergency aortic endografting for exclusion of the pseudoaneurysm was performed using a 28-mm × 3.75-cm AneuRx device. Gastrointestinal hemorrhage ceased. CT scanning at 6 months confirmed the absence of a pseudoaneurysm, and the patient remains symptom free at 18 months.Conclusions:Endovascular treatment of aortoenteric fistula may represent a technique for treating gastrointestinal hemorrhage and for lessening the morbidity and mortality of open repair.
Neutron spectrum measurements using miniature proton recoil proportional spectrometers

Abstract A system has been developed for measurements of neutron energy spectra in the energy range from approximately 1 keV to 2 MeV, for use in the Purdue University Fast Breeder Blanket Facility. This energy range covers the neutron energy range of interest in fast reactor blankets. The neutron spectroscopy system uses hydrogen- and methane-filled cylindrical proportional counters for the measurements, and two-parameter analysis for discrimination against gamma-ray events in the low-energy hydrogen-filled detector. A detector and preamplifier can be inserted into the blanket with the removal of a single fuel rod having a diameter of 15.3 mm (0.60″).
Multiple cycles of intermittent chemotherapy in metastatic androgen-independent prostate cancer.

Recently, completed phase III studies demonstrated a survival benefit for a fixed number of cycles of docetaxel-containing chemotherapy treatment of androgen-independent prostate cancer (AIPC). Management of patients who respond well to initial chemotherapy for AIPC remains ill-defined. We previously reported that in a select group of such patients, retreatment with the same regimen was feasible and was associated with quality of life gains. Here, we report that multiple cycles of such intermittent chemotherapy are feasible. We prospectively tested intermittent chemotherapy in eight AIPC patients responding to calcitriol plus docetaxel who reached a serum prostate-specific antigen (PSA) or =50% and 1 ng ml(-1). The median duration of the first treatment holiday was 20 weeks (13-74 weeks) and all patients retained sensitivity to retreatment. Four patients were eligible for a second chemotherapy holiday, and the median duration was 21 weeks (17-28 weeks). Two patients elected to take a third chemotherapy holiday, which lasted 10 and 28 weeks. The median time to treatment failure was 26.5 months (95% CI 23.6-29.4 months), and the median survival is 41 months (95% CI 33.7-48.3 months). Multiple cycles of intermittent chemotherapy interrupted by clinically meaningful treatment holidays are feasible in a subset of AIPC patients treated with this docetaxel-containing regimen. Intermittent chemotherapy for AIPC is feasible and deserves further study.
Ritual and Presentation in Early Buddhist Religious Architecture

The physical organization and layout of Buddhist reliquary mounds, stupas, provides a window into the forms of ritual practiced by Buddhists in the first few centuries B.C. through the end of the second century A.D. Specifically, the manner in which stupas were architecturally presented informs upon the differences in ritual presentation by the clergy and the laity. Attempts by the Buddhist clergy to direct worship and establish a privileged position in regard to the Buddha were resisted by the laity; in contrast, the laity attempted to preserve the egalitarian aspects of Buddhism. Traces of the laity's resistance can be identified in the architectural layouts of ritual spaces of the early Buddhists. The organization of ritual within stupa complexes also illustrates the methods used by early Buddhists to foster group cohesion within a highly individualistic religious tradition.
Designing gully control systems for eroding watersheds

Effective design of gully control systems must consider the gully network as a whole and be based on geomorphologie indicators such as type of network, stream order, and stage of development. Consideration of geomorphologic characteristics allows a ranking of gully treatment priorities that, in turn, promises the highest return for expenditures. Relationships between sediment catch, channel gradient, treatment cost, and height of check dams in a treatment system are presented. Return is considered within a physical rather than economic framework. Future soil savings are the main focus.
A hidden Markov model for detecting multi-gene chromatin domains

* Correspondence: jlarson@hsph.harvard.edu Department of Biostatistics, Harvard University, Boston, MA 02115, USA Full list of author information is available at the end of the article Figure 1 Heatmaps of known gene clusters. The 35 gene region on Ch6 from Npy to 2410066E13Rik as depictured as a heatmap of histone modification and gene expression for (a) the ES cell line and (c) ES and NP cell lines. The 250 gene region on Ch7 from rt2a to Insc as depictured as a heatmap of histone modification and gene expression for (b) the ES cell line and (d) ES and NP cell lines. For all figures on the left (a and c), cluster state assignment is given in the first and second tracks and HMM state assignments are in the third and fourth tracks (red for active state, blue for non-active state, yellow for null state). For figures on the right (b and d), NP HMM state assignment is given in the first and second tracks and ES HMM state assignments are in the third and fourth tracks. Whether (black) or not (white) a gene is a respective gene cluster in shown in the bottom track in all figures. Larson and Yuan BMC Bioinformatics 2010, 11(Suppl 10):O5 http://www.biomedcentral.com/1471-2105/11/S10/O5
Two-dimensional correlation spectroscopy reveals coupled immunoglobulin regions of differential flexibility that influence stability.

Despite the well-accepted importance of protein flexibility and dynamics in molecular recognition and conformational stability, our understanding of these relationships is incomplete. Immunoglobulin flexibility is essential for antigen binding and adaptation to diverse molecular shapes and sizes. The inherent flexibility of immunoglobulins also renders these molecules suitable for investigating the possible relationships between protein flexibility and stability. To better understand these inter-relationships, we employ generalized perturbation-based two-dimensional correlation FTIR spectroscopy to monitor the time evolution of H−D exchange of an IgG1 as a function of pH. The differential flexibility of various immunoglobulin regions is described in response to an external perturbation and shown to vary widely. The greatest number of regions with differential exchange rates and, thus differential flexibility, is seen at pH 6. Approximately seven, six, five, and four separate states that exchange with diff...
THE INAUGURAL NOEL BUTLIN LECTURE: WORLD FACTOR MIGRATIONS AND DEMOGRAPHIC TRANSITIONS

This lecture explores the connection between demographic transitions, mass migrations and international capital flows. It reviews how demographic transitions influence the size of age cohorts, and then how these changes in age distribution influence excess demands in receiving regions and excess supplies in sending regions. The lecture offers four examples – two from the first global century and two from the second global century – where shocks generated by demographic transitions have had an enormous impact on factor flows: European mass migrations to the New World before 1914; African mass migrations to the OECD over the past two decades; British capital export to the New World before 1914; and capital flows across East Asian borders after 1950 and before the melt down of the 1990s. The lecture concludes with an assessment of the demographic contribution to the East Asian miracle (and slowdown) over the past half century.
Prostate-Specific Antigen Level at Initiation of Hormonal Therapy After Prostate-Specific Antigen Failure Following Prostatectomy or Radiotherapy and Therapeutic Response

OBJECTIVES To determine the pretreatment factors associated with an undetectable prostate-specific antigen (PSA) nadir after 8 months of androgen suppression therapy (AST). METHODS The study cohort comprised 137 men with an increasing PSA level after surgery or radiotherapy performed for localized prostate cancer who had undergone AST. Cox regression multivariate analyses were used to identify the factors associated with a PSA nadir of 0.2 ng/mL or less 8 months after AST initiation. RESULTS The PSA level at the initiation of AST was associated with a PSA nadir of 0.2 ng/mL or less after 8 months of AST, as both a continuous variable (adjusted odds ratio [OR] 0.44, P = 0.0001) and a categorical variable, with PSA greater than 10 ng/mL (OR 0.16, P = 0.007). The percentage of patients with a PSA nadir of 0.2 ng/mL or less was 86%, 72%, 75%, 67%, and 25% for men with a PSA level at the initiation of AST of 4 ng/mL or less, greater than 4 to 10 ng/mL, greater than 10 to 20 ng/mL, greater than 20 to 50 ng/mL, and greater than 50 ng/mL, respectively. CONCLUSIONS An elevated PSA level before the initiation of AST was significantly associated with a decreased chance of a PSA nadir of 0.2 ng/mL or less after 8 months of AST. Given the association between the PSA nadir after AST and prostate-cancer specific mortality, men with increasing PSA levels could be considered for Phase II and III clinical trials evaluating the effect of adding novel systemic therapies to AST on the interval to prostate-cancer specific mortality.
Assessment of the Impact of Climate Shifts on Malaria Transmission in the Sahel

Climate affects malaria transmission through a complex network of causative pathways. We seek to evaluate the impact of hypothetical climate change scenarios on malaria transmission in the Sahel by using a novel mechanistic, high spatial- and temporal-resolution coupled hydrology and agent-based entomology model. The hydrology model component resolves individual precipitation events and individual breeding pools. The impact of future potential climate shifts on the representative Sahel village of Banizoumbou, Niger, is estimated by forcing the model of Banizoumbou environment with meteorological data from two locations along the north–south climatological gradient observed in the Sahel—both for warmer, drier scenarios from the north and cooler, wetter scenarios from the south. These shifts in climate represent hypothetical but historically realistic climate change scenarios. For Banizoumbou climatic conditions (latitude 13.54 N), a shift toward cooler, wetter conditions may dramatically increase mosquito abundance; however, our modeling results indicate that the increased malaria transmissibility is not simply proportional to the precipitation increase. The cooler, wetter conditions increase the length of the sporogonic cycle, dampening a large vectorial capacity increase otherwise brought about by increased mosquito survival and greater overall abundance. Furthermore, simulations varying rainfall event frequency demonstrate the importance of precipitation patterns, rather than simply average or time-integrated precipitation, as a controlling factor of these dynamics. Modeling results suggest that in addition to changes in temperature and total precipitation, changes in rainfall patterns are very important to predict changes in disease susceptibility resulting from climate shifts. The combined effect of these climate-shift–induced perturbations can be represented with the aid of a detailed mechanistic model.
The microstructural path of grain-boundary-nucleated phase transformations

Abstract Microstructural path functions, Sv(t) = f{Xv(t)}, where Xv is the volume fraction transformed and Sv is the interfacial area per unit volume (separating transformed from untransformed material), are derived for transformations in which the product phase nucleates either at parent phase grain boundaries, grain edges or grain corners and grows at a constant rate. The treatment considers that either there is a fixed number of pre-existing nuclei, or nucleation is at a constant rate, or some combination of these two means of nucleation are operative. The rate equations for Xv are deduced using existing formalisms and by using the same basic premises to treat the problem of impingement, the Sv rate equations are derived for the first time. The microstructural path functions are obtained by eliminating time from these rate equations. An example of the usefulness of the microstructural path function to model recrystallization in an aluminum-gold alloy is presented.
Affinity-labeling of anti-lactose antibody

Abstract Purified anti-lactose antibodies induced in the horse and rabbit with a bacterial vaccine have been subjected to affinity-labeling with two bromoacetyl derivatives of lactose-containing ligands. The synthesis of these new radioactive reagents is described and the optimum conditions for the labeling reaction given. The specificity of the reaction has been demonstrated by inhibition with lactose. The maximum extent of specific labeling observed was 1·5 mole of label per mole of 7S antibody. The distribution of the label between heavy and light chains was measured with the separated chains fractionated by acrylamide gel electrophoresis. Except for one antibody preparation the heavy chain carried between 77 and 90 per cent of the total label. It is concluded that bromoacetyl derivatives of appropriate ligands can be used to label the hypervariable regions of the heavy chains present in antibody with anti-lactose specificity.
Prolactin increases survival and migration of ovarian cancer cells: Importance of prolactin receptor type and therapeutic potential of S179D and G129R receptor antagonists

Variably-spliced prolactin receptors (PRLRs) and PRL are expressed by the ovarian cancer cell lines, TOV-112D, OV-90 and TOV-21G. Incubation in the PRLR antagonists, G129R- or S179D-PRL, or anti-PRL reduced cell number, indicating a functional autocrine PRL growth loop. Added PRL promoted, and the antagonists decreased, cell migration. When cells were stressed, added PRL decreased apoptosis and increased survival, and the antagonists had the opposite effect. Cells expressing higher long:short PRLR ratios had increased growth, survival and migration in response to PRL. Results suggest that PRLR antagonists may be therapeutically beneficial in ovarian cancer.
Rate-dependent plastic flow in polycrystalline silver at ambient temperature

This investigation is a continuation of work by Logan, Castro, and Mukherjee in which the mechanical properties of cold-worked (about 12 percent) polycrystalline silver at low temperature (77 to 473 K) were studied. Those authors interpreted their results as support for the intersection of dislocations as the controlling mechanism for plastic flow. That conclusion seems to have been based largely on the observation that the activation area, A, decreases with increasing strain, as would be theoretically expected. However, from strain-rate change tests performed over a strain range of 20 percent at 77 K, those investigators found a decrease of only a factor of two in A. In the present investigation, the proposition of the dislocation-intersection mechanism was analogously tested with annealed polycrystalline silver. If the dislocation intersection mechanism is appropriate, a more demonstrative decrease in A (e.g., over a factor of ten) would be expected in this case over the same strain range of 20 percent.
Phonon interactions in the luminescence of amorphous silicon

Abstract Experimental data and a new model of luminescence in glow-discharge-deposited amorphous silicon are described. The shape of the luminescence excitation spectrum rules out the previous model based on zero-phonon transitions. Instead, phonon interactions give a Stokes shift of 0.4–0.5 eV and the recombination is due to self-trapping of excitons bound to band tail localized states. The model explains the luminescence peak position and line width, the Stokes shift, and the thermal quenching of the luminescence intensity.
Invertebrate Allorecognition: The Origins of Histocompatibility

Alloimmune specificity and histocompatibility, driven by genetic polymorphism, are ancient determinants of self-/non-self-recognition. Recent molecular genetic evidence has revealed an allodeterminant in the cnidarian Hydractinia that consistently predicts histocompatibility reactions.
Commercial Bumble Bee Pollination of Lowbush Blueberry

The commercial bumble bee, Bombus impatiens, has been used in Maine lowbush blueberry since the late 1990s. Studies conducted in 1995–1998 and published in 2001 showed that B. impatiens was a good ...
Influence of nitric oxide on agonist-mediated calcium mobilization in platelets

Recent studies have characterized endothelium-derived relaxing factor as nitric oxide. It appears to exert its effect by elevating intracellular levels of cyclic GMP. In this study we confirm that nitric oxide is a potent inhibitor of agonist-induced irreversible aggregation. At the concentrations tested nitric oxide effectively blocked thrombin-stimulated mobilization of cytosolic-free calcium in Fura 2-loaded platelets. In addition, nitric oxide prevented the inositol 1,4,5-trisphosphate-stimulated calcium rise in cytosolic calcium in saponin-permeabilized Fura 2-loaded platelets. Similar to the action of adenylate cyclase stimulators, nitric oxide facilitated lowering of calcium levels raised by the action of agonists. The specific mechanism by which it exerts its effect on intracellular levels of calcium is not clear.
An adjustable double running suture technique for keratoplasty

In a retrospective analysis, we examined 30 consecutive cases of penetrating keratoplasty in which a double running 10−0/11−0 nylon suture technique was used and the 10−0 suture was adjusted early in the postoperative period to reduce astigmatism. When the response to suture adjustment was inadequate, the presence of the 11−0 suture allowed for early (ten to 18 weeks) removal of the 10−0 suture. Rapid visual recovery (12.3 ± 0.95 weeks; mean ± standard error) and low levels of final astigmatism (2.66 ± 0.24 diopters) were achieved. Visual acuity was 20/20 to 20/40 in 25 of the 28 patients (89%) who were visually rehabilitated. In these 28 patients, visual acuity remained stable for the remainder of the study. All patients had a minimum of six months' follow-up from the time of surgery; mean follow-up was 10.6 ± 1.70 months.
Artificial acidification of a non-acidic and an acidic headwater stream in Maine, USA

Two headwater streams with low DOC and different pHs (4.5-4.8 and 5-6.5) were acidified with H2SO4 to pH 4.1 and 4.5, respectively, for 24-h periods. Neutralization of the added acid occurred by protonation of ANC (HCO3-dominated in the higher pH stream), desorption of Ca (< 15 microeq litre(-1)) and Mg (<6 microeq litre(-1)), and desorption and dissolution of AL (<250 microg litre(-1)) from the stream bed. The concentrations of dissolved organic carbon (DOC) remained constant within the experimental reaches. The concentrations of Na, K an H4SiO4 also remained constant, indicating no detectable increase in the rate of chemical weathering in the stream bed. After acid addition was stopped, concentrations of Ca, Mg and Al decreased to below background, indicating reversible ion exchange as the principal mechanism for the mobility of Ca and Mg and to a lesser extent for Al. Repeated acidifications indicated that significant regeneration of cations on the exchange surfaces of the stream substrate occurs rapidly.
Improving the distribution of Doxil® in the tumor matrix by depletion of tumor hyaluronan

Liposomes improve the pharmacokinetics and safety of rapidly cleared drugs, but have not yet improved the clinical efficacy compared to the non-encapsulated drug. This inability to improve efficacy may be partially due to the non-uniform distribution of liposomes in solid tumors. The tumor extra-cellular matrix is a barrier to distribution and includes the high molecular weight glycosaminoglycan, hyaluronan (HA). Strategies to remove HA or block its synthesis may improve drug delivery into solid tumors. Orally administered methylumbelliferone (MU) is an inhibitor of HA synthesis, but it is limited by low potency and limited solubility. In this study, we encapsulate a water-soluble phosphorylated prodrug of MU (MU-P) in a liposome (L-MU-P). We demonstrate that L-MU-P is a more potent inhibitor of HA synthesis than oral MU in the 4T1 murine mammary carcinoma model using both a quantitative ELISA and histochemistry. We show that HA depletion improves the tumor distribution of liposomes computed using Mander's colocalization analysis of liposomes with the tumor vasculature. Hyaluronan depletion also increases the fraction of the tumor area positive for liposomes. This improved distribution extends the overall survival of mice treated with Doxil®.
Complex river terrace development in the Nenana Valley near Healy, Alaska

A complex sequence of river terraces in the Nenana Valley was examined to determine whether the surfaces were depositional or erosional in origin. Of prime concern was the identification of outwash derived from the Healy (early Wisconsin) and Riley Creek I (late Wisconsin) glaciations. Two terraces were formed during the Healy glacial cycle. The higher level represents the depositional surface of the Healy outwash. The lower level was formed during recession of the Healy ice when approximately 18 metres of that outwash was removed. The erosion was initiated when glacial Lake Moody, dammed behind the Healy moraine, spilled over the drainage divide and began excavation of the Nenana gorge. The surface of Riley Creek [] outwash has been offset by faulting near the gorge mouth. Isolated remnants of that surface stand at different elevations, complicating the correlation of downvalley outwash with the Riley Creek I moraine. The evolution of the Nenana gorge is associated with spasmodic development of erosional terraces throughout post-Healy time as the Nenana River attempted to establish a new equilibrium condition. This erosional trend has been interrupted only by out-wash deposition during episodic expansion of the Riley Creek ice.
Clinical and Hemodynamic Results of Intraaortic Balloon Pumping and Surgery for Cardiogenic Shock

The AVCO balloon pump has been employed in treating 40 patients with cardiogenic shock from acute myocardial infarction (CS-MI). All patients were given a trial of medical therapy with hemodynamic monitoring. The time from the development of shock to institution of intraaortic balloon pumping (IABP) was less than 24 hours in all but nine patients. Prior to IABP the mean hemodynamic values were: cardiac index (CI) 1.7 liters/min/m2; mean arterial pressure (MAP) 66 mm Hg; pulmonary artery wedge pressure (PAW) 22 mm Hg. After 24-48 hours of IABP the CI and MAP had increased 0.8 liters/min/m2 and 8 mm Hg, respectively, and the PAW had decreased 4.8 mm Hg. During IABP the shock syndrome was reversed in 31 patients. Four of 25 patients treated with IABP alone survived to be discharged, but two have died from subsequent infarctions. Because of the persistent high mortality, 15 patients judged unable to survive off IABP have undergone emergency surgical procedures with IABP continuing during preoperative angiogra...
Graded Materials for Resistance to Contact Deformation and Damage

The mechanical response of materials with spatial gradients in composition and structure is of considerable interest in disciplines as diverse as tribology, geology, optoelectronics, biomechanics, fracture mechanics, and nanotechnology. The damage and failure resistance of surfaces to normal and sliding contact or impact can be changed substantially through such gradients. This review assesses the current understanding of the resistance of graded materials to contact deformation and damage, and outlines future research directions and possible applications for graded materials.