To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure email@example.com
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
The aim of this study was to examine the population structure, transmission and spatial relationship between genotypes of Shiga toxin-producing Escherichia coli (STEC) and Campylobacter jejuni, on 20 dairy farms in a defined catchment. Pooled faecal samples (n = 72) obtained from 288 calves were analysed by real-time polymerase chain reaction (rtPCR) for E. coli serotypes O26, O103, O111, O145 and O157. The number of samples positive for E. coli O26 (30/72) was high compared to E. coli O103 (7/72), O145 (3/72), O157 (2/72) and O111 (0/72). Eighteen E. coli O26 and 53 C. jejuni isolates were recovered from samples by bacterial culture. E. coli O26 and C. jejuni isolates were genotyped using pulsed-field gel electrophoresis and multilocus sequence typing, respectively. All E. coli O26 isolates could be divided into four clusters and the results indicated that E. coli O26 isolates recovered from calves on the same farm were more similar than isolates recovered from different farms in the catchment. There were 11 different sequence types of C. jejuni isolated from the cattle and 22 from water. An analysis of the population structure of C. jejuni isolated from cattle provided evidence of clustering of genotypes within farms, and among groups of farms separated by road boundaries.
The Fontan operation can create a stable circulation from childhood through early adulthood. However, the absence of a sub-pulmonary pumping chamber leads to a physiology in which exercise capacity is limited and decreases with age starting in adolescence. The limitation in exercise capacity is more pronounced at peak levels of exercise, but is still present during more modest levels of activity. The underlying causes of exercise impairment relate to both central cardiovascular factors (oxygen delivery) and peripheral factors (oxygen extraction). Interventions to improve cardiac preload and to improve lean muscle mass may help to improve exercise capacity and, perhaps, will alter the “natural history” of the progressive decline.
Erythropoietin (EPO) gene therapy can be used for several purposes; however, its effects on reproductive performance are unknown. The aim of this study was to evaluate the toxicological effects of non-viral (EPO) gene transfer on sperm motility, viability, morphology and concentration. Rabbit EPO cDNA was cloned into a pTarget mammalian expression vector. Rabbits were administered with: (1) pTarget/EPO vector, (2) recombinant human EPO (rHuEpo) and (3) saline (control). Both pTarget/EPO and rHuEpo significantly increased (P < 0.05) hematocrit levels 1 week after injection and they remained significantly higher than the control for up to 5 weeks (P < 0.05), showing that both EPO treatments were effective in stimulating the production of red blood cells in rabbits. The EPO gene transfer or rHuEPO administration had no significant effect (P > 0.05) on sperm motility, vigor, viability, concentration or morphology in the testis.
Spherical aberration corrected Atomic Number Contrast Scanning Electron Microscopy (Z-STEM) has recently demonstrated an amazing ability to not only obtain sub-angstrom levels of detail but also yield chemical information at that level as well. With an optimal probe size of 0.8 Å, extremely detailed images of CdSe nanocrystals were obtained showing the lattice structure and surface morphology. As an example of the usefulness of this technique, a sample of CdSe nanocrystals prepared using trioctylphosphine oxide (TOPO) as the surfactant was compared to a sample of CdSe prepared using a mixture of TOPO and hexadecylamine (HDA) as the surfactant. The TOPO/HDA nanocrystals exhibit a narrower size distribution and several orders of magnitude greater fluorescence compared to that of the TOPO only nanocrystals. Interestingly, the Z-STEM images show a striking difference in nanocrystal morphology as the result of the addition of HDA to the reaction mixture. This result suggests surface morphology can be tuned through judicious choice of surfactant. A second example of Z- STEM imaging involves the characterization of CdSe/ZnS core/shell nanocrystals. The mass contrast afforded by Z-STEM can easily distinguish between core and shell.
The aberration-corrected STEM allows nanostructures to be investigated with greater resolution and sensitivity than ever before. Single atom sensitivity is achieved both in imaging and also for spectroscopy, for atoms on surfaces or within the bulk. Nanocrystal size, shape, surface termination, 3D structure and the presence of any defects can be seen with unprecedented ease. The improved sensitivity provides improved input for theory, allowing new insights into nanostructure properties and the origin of their unique functionality. Furthermore, the larger aperture available with aberration-corrected STEM improves the depth resolution dramatically. Nanometer depth resolution can be achieved by simply taking a focal series of images, which may then be reconstructed into a 3D rendering of the material in the same manner as with confocal optical microscopy but maintaining sensitivity to individual atoms.
The field of neuroscience draws together many disciplines in the study of the nervous system and the properties of mind. Although understanding the basic structure and physiology of the brain and its processes has led to high-impact findings, it is typically the manipulation or application of this knowledge that is most interesting to individuals outside the scientific community. The development and use of neurotechnologies, those tools and devices that interact with and modulate the nervous system, is a fast-emerging area of technical achievement that has vast potential to impact our understanding of, and interaction with the brain. The rapidly growing field of neurotechnology research and development employs knowledge and tools from diverse fields. It is through interdisciplinary, collaborative thinking that great advances have been made to develop, research, and transfer neurotechnology to the clinic and beyond. Such technologies include functional magnetic resonance imaging (fMRI), electroencephalography (EEG), functional near-infrared spectroscopy (fNIRS), deep brain stimulation (DBS), and neural prosthetics. Investigation into the mechanisms and functions of the brain is leading to a vastly improved understanding of brain disease, injuries, human cognition, and behavior, and will give us an unprecedented ability to heal, enhance, and manipulate the nervous system.
Many ethical, legal, and social implications (ELSI) of these technologies and their identified and potential uses have emerged, with others still to surface, as the scientific community and general public have increasing access to medical and commercial neurotechnologies (Eaton & Illes 2007).
The virulence of Campylobacter jejuni and C. coli isolated from various water sources was compared with that of clinical strains by in vitro assays of adhesion, invasion and cytotoxicity to HeLa cells. Variation in degree of attachment was observed, but this did not appear to be related to strain source, However, water strains were less invasive and less cytotoxic to HeLa cells than clinical strains as shown by immunofluorescence and electron microscopy.
These differences were particularly evident between clinical and water isolates of the same serotype and biotype implicated in an outbreak of campylobacter enteritis in a school. The enhanced virulence of the clinical isolates, possibly induced by passage, was confirmed by colonization tests on infant mice.
The biochemical and biological properties of the flagella of Campylobacter jejuni have been investigated using two variants selected from a flagellate, motile clinical isolate (strain 81116): a flagellate, non-motile variant (SF-1) and an aflagellate variant (SF-2). Phenotypic and biochemical analysis of the strains and amino acid analysis of the isolated flagella suggest that the variants differed from the wild-type strain only in the absence of flagella and/or motility. The aflagellato variant poorly colonized the gastrointestinal tract of infant mice but the flagellate, non-motile variant colonized the mice as successfully as the wild-type strain.35S-labelled organisms were used to investigate the attachment of the variants to human epithelial cell monolayers in vitro. The flagellate, non-motile strain attached more efficiently to the cells than the wild-type strain or the aflagellate strain. Differences in attachment suggest that an adhesin is intimately associated with flagella of C jejuniand that active flagella mediate only a tenuous association with host cells. This adhesin attached most efficiently to cells of intestinal epithelial origin and was not specifically inhibited by various sugars.
Cross-sectional research has demonstrated poorer function and health-related quality of life (HRQOL) in those with multiple sclerosis (MS) but less is known about change over time. The goals of this study were to measure change in HRQOL and identify factors associated with change.
HRQOL was assessed at baseline and annually over two subsequent years using the Multiple Sclerosis Quality of Life Inventory. Function was assessed using the Expanded Disability Status Scale (EDSS) and the Multiple Sclerosis Functional Composite. Annualized rate of change was calculated for all twenty outcomes. Mixed effects modeling (univariate followed by multivariate) was used to examine the associations among patient characteristics and the age- and sex-adjusted Physical Component Summary (PCS) and Mental Component Summary (MCS) at study initiation and over the two years of follow-up.
Of 300 participants, 288 (96%) provided at least one assessment and are included in this analysis. Although 14 of the 20 outcomes showed a mean decline, only two (SF-36 physical function, p=0.018 and the EDSS, p<0.001) were statistically significant. The SF-36 social function showed a significant improvement (p=0.031). Only two variables were significantly associated with a decreased rate of decline or improvement over two years, including being female (PCS, p=0.001) and use of visiting nurse services (MCS, p<0.001).
HRQOL is relatively stable over two years of follow-up, particularly for mentally-oriented outcomes. Further research with a longer period of follow-up is needed to provide additional insight into factors associated with change in HRQOL in patients with MS.
“Women's movement” is a term widely used by journalists, activists, politicians, scholars, and citizens alike; most people have a general idea of the concept's meaning. Despite the widespread attention to the term since the 1970s, social science is in the early stages of conceptualization (Beckwith 2005a). A quick glance at scholarly work on women's movements indicates there is agreement on neither a general definition nor how the concept should be used in empirical research. In fact, researchers seldom give an explicit definition of the term. Can we be sure that women's movement scholars are talking about the same thing? If not, studies and theories of women's movements risk being inaccurate and perhaps even unintentionally misleading. Our own research on women's movements and women's policy agencies reveals a debate among scholars that has left unanswered many questions about how to use women's movements as a concept for good research. The more notable ones include:
How can movement characteristics be measured?
How can movement impact be measured?
What distinguishes women participants in government and politics from the movement?
Can men be in women's movements?
Is “women's movement” a singular or collective noun, or are there many movements?
Are women's movements defined by their mobilization of women exclusively, or by their goals, or both? For example, are women's peace movements women's movements?
The absence of a consensus about the conceptual use of “women's movement” is quite similar for the related concept “feminist movement/feminism,” but with a controversial twist.
State feminism captures the emergence of a new set of state–society relations and introduces a gendered view of state action to empirical and comparative analysis. It is based on the expectation that democratic governments, to be successful, can and should promote women's status and rights in relation to men's, however those rights are defined in specific cultural contexts, and should work to undermine the gender-based hierarchies that contribute to enduring sex-based inequities. In other words, the concept is based on the premise that democracies can and should be feminist. As we argue in this chapter, since the mid-1990s, scholars throughout the world have increasingly used state feminism to study the relations between women's movements and women's policy agencies (WPAs) – “state-based mechanisms charged formally with furthering women's status and gender equality” (RNGS 2006: 1). In this view, WPAs are a potential conduit for women's movement actors and ideas to enter the affairs of government and to influence the process of policy formulation and implementation. Such access thus increases the chances to realize the highly transversal and difficult-to-achieve feminist agenda. In its current usage, therefore, state feminism implies a focus on women's policy agencies in relation to women's movements and a complex process that may or may not produce a certain set of explicitly feminist outcomes.
State feminism has not always been associated with WPAs, or, as the United Nations calls them, “national machineries for the advancement of women” (UN 2006).