522 research outputs found
A missing dimension in measures of vaccination impacts
Immunological protection, acquired from either natural infection or vaccination, varies among hosts, reflecting underlying biological variation and affecting population-level protection. Owing to the nature of resistance mechanisms, distributions of susceptibility and protection entangle with pathogen dose in a way that can be decoupled by adequately representing the dose dimension. Any infectious processes must depend in some fashion on dose, and empirical evidence exists for an effect of exposure dose on the probability of transmission to mumps-vaccinated hosts [1], the case-fatality ratio of measles [2], and the probability of infection and, given infection, of symptoms in cholera [3]. Extreme distributions of vaccine protection have been termed leaky (partially protects all hosts) and all-or-nothing (totally protects a proportion of hosts) [4]. These distributions can be distinguished in vaccine field trials from the time dependence of infections [5]. Frailty mixing models have also been proposed to estimate the distribution of protection from time to event data [6], [7], although the results are not comparable across regions unless there is explicit control for baseline transmission [8]. Distributions of host susceptibility and acquired protection can be estimated from dose-response data generated under controlled experimental conditions [9]–[11] and natural settings [12], [13]. These distributions can guide research on mechanisms of protection, as well as enable model validity across the entire range of transmission intensities. We argue for a shift to a dose-dimension paradigm in infectious disease science and community health
Linking a dermal permeation and an inhalation model to a simple pharmacokinetic model to study airborne exposure to di(n-butyl) phthalate
Six males clad only in shorts were exposed to high levels of airborne di(n-butyl) phthalate (DnBP) and diethyl phthalate (DEP) in chamber experiments conducted in 2014. In two 6 h sessions, the subjects were exposed only dermally while breathing clean air from a hood, and both dermally and via inhalation when exposed without a hood. Full urine samples were taken before, during, and for 48 h after leaving the chamber and measured for key DnBP and DEP metabolites. The data clearly demonstrated high levels of DnBP and DEP metabolite excretions while in the chamber and during the first 24 h once leaving the chamber under both conditions. The data for DnBP were used in a modeling exercise linking dose models for inhalation and transdermal permeation with a simple pharmacokinetic model that predicted timing and mass of metabolite excretions. These models were developed and calibrated independent of these experiments. Tests included modeling of the “hood-on” (transdermal penetration only), “hood-off” (both inhalation and transdermal) scenarios, and a derived “inhalation-only” scenario. Results showed that the linked model tended to duplicate the pattern of excretion with regard to timing of peaks, decline of concentrations over time, and the ratio of DnBP metabolites. However, the transdermal model tended to overpredict penetration of DnBP such that predictions of metabolite excretions were between 1.1 and 4.5 times higher than the cumulative excretion of DnBP metabolites over the 54 h of the simulation. A similar overprediction was not seen for the “inhalation-only” simulations. Possible explanations and model refinements for these overpredictions are discussed. In a demonstration of the linked model designed to characterize general population exposures to typical airborne indoor concentrations of DnBP in the United States, it was estimated that up to one-quarter of total exposures could be due to inhalation and dermal uptake
Multicolour correlative imaging using phosphor probes
Correlative light and electron microscopy exploits the advantages of optical methods, such as multicolour probes and their use in hydrated live biological samples, to locate functional units, which are then correlated with structural details that can be revealed by the superior resolution of electron microscopes. One difficulty is locating the area imaged by the electron beam in the much larger optical field of view. Multifunctional probes that can be imaged in both modalities and thus register the two images are required. Phosphor materials give cathodoluminescence (CL) optical emissions under electron excitation. Lanthanum phosphate containing thulium or terbium or europium emits narrow bands in the blue, green and red regions of the CL spectrum; they may be synthesised with very uniform-sized crystals in the 10- to 50-nm range. Such crystals can be imaged by CL in the electron microscope, at resolutions limited by the particle size, and with colour discrimination to identify different probes. These materials also give emissions in the optical microscope, by
multiphoton excitation. They have been deposited on the surface of glioblastoma cells and imaged by CL. Gadolinium oxysulphide doped with terbium emits green photons by either ultraviolet or electron excitation. Sixty-nanometre crystals of this phosphor have been imaged in the atmospheric scanning electron microscope (JEOL ClairScope). This probe and microscope combination allow correlative imaging in hydrated samples. Phosphor probes should prove to be very useful in correlative light and electron microscopy, as fiducial
markers to assist in image registration, and in high/super resolution imaging studies
External tagging does not affect the feeding behavior of a coral reef fish, Chaetodon vagabundus (Pisces: Chaetodontidae)
Author Posting. © The Author(s), 2009. This is the author's version of the work. It is posted here by permission of for personal use, not for redistribution. The definitive version was published in Environmental Biology of Fishes 86 (2009): 447-450, doi:10.1007/s10641-009-9545-9.Increasingly, the ability to recognize individual fishes is important for studies of population
dynamics, ecology, and behavior. Although a variety of methods exist, external tags remain one
of the most widely applied because they are both effective and cost efficient. However, a key
assumption is that neither the tagging procedure nor the presence of a tag negatively affects the
individual. While this has been demonstrated for relatively coarse metrics such as growth and
survival, few studies have examined the impact of tags and tagging on more subtle aspects of
behavior. We tagged adult vagabond butterflyfish (Chaetodon vagabundus) occupying a 30-ha
insular reef in Kimbe Bay, Papua New Guinea, using a commonly-utilized t-bar anchor tag. We
quantified and compared feeding behavior (bite rate), which is sensitive to stress, of tagged and
untagged individuals over four separate sampling periods spanning four months post-tagging.
Bite rates did not differ between tagged and untagged individuals at each sampling period and,
combined with additional anecdotal observations of normal pairing behavior and successful
reproduction, suggest that tagging did not adversely affect individuals.The authors gratefully
acknowledge funding from the Fulbright Program, National Science Foundation and the
Australian Research Council
Diagnostic and treatment characteristics of polycystic ovary syndrome: descriptive measurements of patient perception and awareness from 657 confidential self-reports
BACKGROUND: This investigation was undertaken to describe patient perception and awareness of the polycystic ovary syndrome (PCOS), the most common cause of anovulation/oligoovulation among women of reproductive age. METHODS: Fifteen parameters were evaluated by a computer-based research instrument accessed by a large, unscreened population. Incomplete questionnaires were not entered, and responses were electronically tabulated to block duplicate submissions. RESULTS: From 657 participants, the majority (63%) were between 26–34 years old; mean BMI was 30.4 kg/m(2). 343 of 657 had at least one pregnancy and 61% of the study group had taken fertility medicine (any type) at least once. Physicians were the most common provider of PCOS information for all study participants, irrespective of age. Patient emotions associated with the diagnosis of PCOS included "frustration" (67%), "anxiety" (16%), "sadness" (10%), and "indifference" (2%). Self-reported patient aptitude regarding PCOS was scored as high or "very aware" in >60% of women. Respondents were also asked: "If your PCOS could be safely and effectively helped by something else besides fertility drugs or birth control pills, would that interest you?" Interest in alternative PCOS treatments was expressed by 99% of the sample (n = 648). CONCLUSIONS: In our study population, most women associated negative emotions with PCOS although the self-reported knowledge level for the disorder was high. While these women regarded their obstetrician-gynecologist as integral to their PCOS education, traditional PCOS therapies based on oral contraceptives or ovulation induction agents were regarded as unsatisfactory by most women
Manganese as a Probe of Fungal Degradation of Wood
Transition state metals, such as manganese (Mn) and iron (Fe), have been reported to be involved in fungal degradation of wood (Ellis, 1959; Shortl
The HLA class II allele DRB1*1501 is over-represented in patients with idiopathic pulmonary fibrosis
Background: Idiopathic pulmonary fibrosis (IPF) is a progressive and medically refractory lung disease with a grim prognosis. Although the etiology of IPF remains perplexing, abnormal adaptive immune responses are evident in many afflicted patients. We hypothesized that perturbations of human leukocyte antigen (HLA) allele frequencies, which are often seen among patients with immunologic diseases, may also be present in IPF patients. Methods/Principal Findings: HLA alleles were determined in subpopulations of IPF and normal subjects using molecular typing methods. HLA-DRB1*15 was over-represented in a discovery cohort of 79 Caucasian IPF subjects who had lung transplantations at the University of Pittsburgh (36.7%) compared to normal reference populations. These findings were prospectively replicated in a validation cohort of 196 additional IPF subjects from four other U.S. medical centers that included both ambulatory patients and lung transplantation recipients. High-resolution typing was used to further define specific HLA-DRB1*15 alleles. DRB1*1501 prevalence in IPF subjects was similar among the 143 ambulatory patients and 132 transplant recipients (31.5% and 34.8%, respectively, p = 0.55). The aggregate prevalence of DRB1*1501 in IPF patients was significantly greater than among 285 healthy controls (33.1% vs. 20.0%, respectively, OR 2.0; 95%CI 1.3-2.9, p = 0.0004). IPF patients with DRB1*1501 (n = 91) tended to have decreased diffusing capacities for carbon monoxide (DLCO) compared to the 184 disease subjects who lacked this allele (37.8±1.7% vs. 42.8±1.4%, p = 0.036). Conclusions/Significance: DRB1*1501 is more prevalent among IPF patients than normal subjects, and may be associated with greater impairment of gas exchange. These data are novel evidence that immunogenetic processes can play a role in the susceptibility to and/or manifestations of IPF. Findings here of a disease association at the HLA-DR locus have broad pathogenic implications, illustrate a specific chromosomal area for incremental, targeted genomic study, and may identify a distinct clinical phenotype among patients with this enigmatic, morbid lung disease
Interpersonal and affective dimensions of psychopathic traits in adolescents : development and validation of a self-report instrument
We report the development and psychometric evaluations of a self-report instrument designed to screen for psychopathic traits among mainstream community adolescents. Tests of item functioning were initially conducted with 26 adolescents. In a second study the new instrument was administered to 150 high school adolescents, 73 of who had school records of suspension for antisocial behavior. Exploratory factor analysis yielded a 4-factor structure (Impulsivity α = .73, Self-Centredness α = .70, Callous-Unemotional α = .69, and Manipulativeness α = .83). In a third study involving 328 high school adolescents, 130 with records of suspension for antisocial behaviour, competing measurement models were evaluated using confirmatory factor analysis. The superiority of a first-order model represented by four correlated factors that was invariant across gender and age was confirmed. The findings provide researchers and clinicians with a psychometrically strong, self-report instrument and a greater understanding of psychopathic traits in mainstream adolescents
Visualizing Rank Deficient Models: A Row Equation Geometry of Rank Deficient Matrices and Constrained-Regression
Situations often arise in which the matrix of independent variables is not of full column rank. That is, there are one or more linear dependencies among the independent variables. This paper covers in detail the situation in which the rank is one less than full column rank and extends this coverage to include cases of even greater rank deficiency. The emphasis is on the row geometry of the solutions based on the normal equations. The author shows geometrically how constrained-regression/generalized-inverses work in this situation to provide a solution in the face of rank deficiency
Incidence, prevalence and mortality rates of malaria in Ethiopia from 1990 to 2015: analysis of the global burden of diseases 2015
Background: In Ethiopia there is no complete registration system to measure disease burden and risk factors accurately. In this study, the 2015 Global Burden of Diseases, Injuries and Risk factors (GBD) data were used to analyse the incidence, prevalence and mortality rates of malaria in Ethiopia over the last 25 years.
Methods: GBD 2015 used verbal autopsy (VA) surveys, reports, and published scientific articles to estimate the burden of malaria in Ethiopia. Age and gender-specific causes of death for malaria were estimated using Cause of Death Ensemble Modelling (CODEm).
Results: The number of new cases of malaria declined from 2.8 million (95% uncertainty interval (UI): 1.4-4.5million) in 1990 to 621,345 (95% UI: 462,230-797,442) in 2015. Malaria caused an estimated 30,323.9 deaths (95% UI: 11,533.3-61,215.3) in 1990 and 1,561.7 deaths (95% UI: 752.8-2,660.5) in 2015, a 94.8% reduction over the 25 years. Age-standardized mortality rate of malaria has declined by 96.5% between 1990 and 2015 with an annual rate of change (ARC) of 13.4%. Age-standardized malaria incidence rate among all ages and gender declined by 88.7% between 1990 and 2015. The number of disability-adjusted life years lost (DALY) due to malaria decreased from 2.2 million (95% UI: 0.76-4.7 million) in 1990 to 0.18 million (95% UI: 0.12-0.26 million) in 2015, with a total reduction 91.7%. Similarly, age-standardized DALY rate declined by 94.8% during the same period.
Conclusions: Ethiopia has achieved a 50% reduction target of malaria of the Millennium Development Goals (MDGs). The country should strengthen its malaria control and treatment strategies to achieve the Sustainable Development Goals (SDG)
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