64 research outputs found

    Characterization of Granulations of Calcium and Apatite in Serum as Pleomorphic Mineralo-Protein Complexes and as Precursors of Putative Nanobacteria

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    Calcium and apatite granulations are demonstrated here to form in both human and fetal bovine serum in response to the simple addition of either calcium or phosphate, or a combination of both. These granulations are shown to represent precipitating complexes of protein and hydroxyapatite (HAP) that display marked pleomorphism, appearing as round, laminated particles, spindles, and films. These same complexes can be found in normal untreated serum, albeit at much lower amounts, and appear to result from the progressive binding of serum proteins with apatite until reaching saturation, upon which the mineralo-protein complexes precipitate. Chemically and morphologically, these complexes are virtually identical to the so-called nanobacteria (NB) implicated in numerous diseases and considered unusual for their small size, pleomorphism, and the presence of HAP. Like NB, serum granulations can seed particles upon transfer to serum-free medium, and their main protein constituents include albumin, complement components 3 and 4A, fetuin-A, and apolipoproteins A1 and B100, as well as other calcium and apatite binding proteins found in the serum. However, these serum mineralo-protein complexes are formed from the direct chemical binding of inorganic and organic phases, bypassing the need for any biological processes, including the long cultivation in cell culture conditions deemed necessary for the demonstration of NB. Thus, these serum granulations may result from physiologically inherent processes that become amplified with calcium phosphate loading or when subjected to culturing in medium. They may be viewed as simple mineralo-protein complexes formed from the deployment of calcification-inhibitory pathways used by the body to cope with excess calcium phosphate so as to prevent unwarranted calcification. Rather than representing novel pathophysiological mechanisms or exotic lifeforms, these results indicate that the entities described earlier as NB most likely originate from calcium and apatite binding factors in the serum, presumably calcification inhibitors, that upon saturation, form seeds for HAP deposition and growth. These calcium granulations are similar to those found in organisms throughout nature and may represent the products of more general calcium regulation pathways involved in the control of calcium storage, retrieval, tissue deposition, and disposal

    Imports and isotopes: a modern baseline study for interpreting Iron Age and Roman trade in fallow deer antlers

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    The European Fallow deer (Dama dama dama) became extinct in the British Isles and most of continental Europe at the time of the Last Glacial Maximum, with the species becoming restricted to an Anatolian refugium (Masseti et al. 2008). Human-mediated reintroductions resulted in fallow populations in Rhodes, Sicily, Mallorca, Iberia and other parts of western Europe (Sykes et al. 2013). Eventually, the species was brought to Britain by the Romans during the 1st century AD, with a breeding population being established at Fishbourne Roman Palace (Sykes et al. 2011). The human influence on the present-day distribution of the species makes it particularly interesting from a zooarchaeological perspective. This paper describes my MSc research, as part of the AHRC-funded project Dama International: Fallow Deer and European Society 6000 BC–AD 1600, looking at antlers from Iron Age and Roman sites in Britain for evidence of trade in body parts and whether this can be elucidated by a parallel stable isotope study of modern fallow antlers of known provenance

    Dead or alive?: investigating long-distance transport of live fallow deer and their body parts in antiquity

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    The extent to which breeding populations of fallow deer were established in Roman Europe has been obscured by the possibility that the skeletal remains of the species, in particular Dama foot bones and antlers, were traded over long distances as objects in their own right. This paper sets out to refine our understanding of the evidence for the transportation of living and dead fallow deer in Iron Age and Roman Europe. To achieve this, museum archives containing purportedly early examples of Dama antler were searched, with available specimens sampled for carbon, nitrogen and strontium isotope analyses, and compared with data for archaeological fallow deer from across Europe. Importantly, the resulting isotope values can be interpreted in light of new modern baseline data for fallow deer presented here. Together these multi-isotope results for modern and archaeological fallow deer provide a more critical perspective on the transportation of fallow deer and their body parts in antiquity

    Changes in symptomatology, reinfection, and transmissibility associated with the SARS-CoV-2 variant B.1.1.7: an ecological study

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    Background The SARS-CoV-2 variant B.1.1.7 was first identified in December, 2020, in England. We aimed to investigate whether increases in the proportion of infections with this variant are associated with differences in symptoms or disease course, reinfection rates, or transmissibility. Methods We did an ecological study to examine the association between the regional proportion of infections with the SARS-CoV-2 B.1.1.7 variant and reported symptoms, disease course, rates of reinfection, and transmissibility. Data on types and duration of symptoms were obtained from longitudinal reports from users of the COVID Symptom Study app who reported a positive test for COVID-19 between Sept 28 and Dec 27, 2020 (during which the prevalence of B.1.1.7 increased most notably in parts of the UK). From this dataset, we also estimated the frequency of possible reinfection, defined as the presence of two reported positive tests separated by more than 90 days with a period of reporting no symptoms for more than 7 days before the second positive test. The proportion of SARS-CoV-2 infections with the B.1.1.7 variant across the UK was estimated with use of genomic data from the COVID-19 Genomics UK Consortium and data from Public Health England on spike-gene target failure (a non-specific indicator of the B.1.1.7 variant) in community cases in England. We used linear regression to examine the association between reported symptoms and proportion of B.1.1.7. We assessed the Spearman correlation between the proportion of B.1.1.7 cases and number of reinfections over time, and between the number of positive tests and reinfections. We estimated incidence for B.1.1.7 and previous variants, and compared the effective reproduction number, Rt, for the two incidence estimates. Findings From Sept 28 to Dec 27, 2020, positive COVID-19 tests were reported by 36 920 COVID Symptom Study app users whose region was known and who reported as healthy on app sign-up. We found no changes in reported symptoms or disease duration associated with B.1.1.7. For the same period, possible reinfections were identified in 249 (0·7% [95% CI 0·6–0·8]) of 36 509 app users who reported a positive swab test before Oct 1, 2020, but there was no evidence that the frequency of reinfections was higher for the B.1.1.7 variant than for pre-existing variants. Reinfection occurrences were more positively correlated with the overall regional rise in cases (Spearman correlation 0·56–0·69 for South East, London, and East of England) than with the regional increase in the proportion of infections with the B.1.1.7 variant (Spearman correlation 0·38–0·56 in the same regions), suggesting B.1.1.7 does not substantially alter the risk of reinfection. We found a multiplicative increase in the Rt of B.1.1.7 by a factor of 1·35 (95% CI 1·02–1·69) relative to pre-existing variants. However, Rt fell below 1 during regional and national lockdowns, even in regions with high proportions of infections with the B.1.1.7 variant. Interpretation The lack of change in symptoms identified in this study indicates that existing testing and surveillance infrastructure do not need to change specifically for the B.1.1.7 variant. In addition, given that there was no apparent increase in the reinfection rate, vaccines are likely to remain effective against the B.1.1.7 variant. Funding Zoe Global, Department of Health (UK), Wellcome Trust, Engineering and Physical Sciences Research Council (UK), National Institute for Health Research (UK), Medical Research Council (UK), Alzheimer's Society

    Genomic assessment of quarantine measures to prevent SARS-CoV-2 importation and transmission

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    Mitigation of SARS-CoV-2 transmission from international travel is a priority. We evaluated the effectiveness of travellers being required to quarantine for 14-days on return to England in Summer 2020. We identified 4,207 travel-related SARS-CoV-2 cases and their contacts, and identified 827 associated SARS-CoV-2 genomes. Overall, quarantine was associated with a lower rate of contacts, and the impact of quarantine was greatest in the 16–20 age-group. 186 SARS-CoV-2 genomes were sufficiently unique to identify travel-related clusters. Fewer genomically-linked cases were observed for index cases who returned from countries with quarantine requirement compared to countries with no quarantine requirement. This difference was explained by fewer importation events per identified genome for these cases, as opposed to fewer onward contacts per case. Overall, our study demonstrates that a 14-day quarantine period reduces, but does not completely eliminate, the onward transmission of imported cases, mainly by dissuading travel to countries with a quarantine requirement

    Genomic epidemiology of SARS-CoV-2 in a UK university identifies dynamics of transmission

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    AbstractUnderstanding SARS-CoV-2 transmission in higher education settings is important to limit spread between students, and into at-risk populations. In this study, we sequenced 482 SARS-CoV-2 isolates from the University of Cambridge from 5 October to 6 December 2020. We perform a detailed phylogenetic comparison with 972 isolates from the surrounding community, complemented with epidemiological and contact tracing data, to determine transmission dynamics. We observe limited viral introductions into the university; the majority of student cases were linked to a single genetic cluster, likely following social gatherings at a venue outside the university. We identify considerable onward transmission associated with student accommodation and courses; this was effectively contained using local infection control measures and following a national lockdown. Transmission clusters were largely segregated within the university or the community. Our study highlights key determinants of SARS-CoV-2 transmission and effective interventions in a higher education setting that will inform public health policy during pandemics.</jats:p

    Single-cell measurements of the contributions of cytosolic Na+ and K+ to cell salt tolerance

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    Ion concentrations in the roots of two barley (Hordeum vulgare) varieties that differed in NaCl tolerance were compared after exposure to NaCl. Triple-barreled H_-, K_-, and Na_-selective microelectrodes were used to measure cytosolic activities of the three ions after 5 and 8 d of NaCl stress. In both varieties of barley, it was only possible to record successfully from root cortical cells because the epidermal cells appeared to be damaged. The data show that from the 1st d of full NaCl stress, there were differences in the way in which the two varieties responded. At 5 d, the tolerant variety maintained a 10-fold lower cytosolic Na_ than the more sensitive variety, although by 8 d the two varieties were not significantly different. At this time, the more tolerant variety was better at maintaining root cytosolic K_ in the high-NaCl background than was the more sensitive variety. In contrast to earlier work on K_-starved barley (Walker et al., 1996), there was no acidification of the cytosol associated with the decreased cytosolic K_ activity during NaCl stress. These single-cell measurements of cytosolic and vacuolar ion activities allow calculation of thermodynamic gradients that can be used to reveal (or predict) the type of active transporters at both the plasma membrane and tonoplast

    The Road Less Traveled: How to Manage the Recycling Career Stage

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    This article examines how organizations can better respond to the needs of individuals who are reexamining and changing their chosen career paths. The term, career recycling , reflects a new, growing segment of the workforce describing individuals who are reexamining and changing their career paths. Through exploratory interviews, we found that recyclers were dissatisfied with their careers and willing to accept the risks associated with changing career direction. Recycling is generally triggered by organizational change, personal plateauing and/or personal crisis. Firms may need to reassess, redesign, and reevaluate key human resource activities, such as employee counseling, job sharing, and compensation benefits in the light of this new phenomenon
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