Nanorheology of viscoelastic shells: Applications to viral capsids

We study the microrheology of nanoparticle shells [Dinsmore et al. Science 298, 1006 (2002)] and viral capsids [Ivanovska et al. PNAS 101, 7600 (2004)] by computing the mechanical response function and thermal fluctuation spectrum of a viscoelastic spherical shell that is permeable to the surrounding solvent. We determine analytically the damped dynamics of the shear, bend, and compression modes of the shell coupled to the solvent both inside and outside the sphere in the zero Reynolds number limit. We identify fundamental length and time scales in the system, and compute the thermal correlation function of displacements of antipodal points on the sphere and the mechanical response to pinching forces applied at these points. We describe how such a frequency-dependent antipodal correlation and/or response function, which should be measurable in new AFM-based microrheology experiments, can probe the viscoelasticity of these synthetic and biological shells constructed of nanoparticles.Comment: 17 page

A FUSE Survey of Interstellar Molecular Hydrogen in the Small and Large Magellanic Clouds

We describe a moderate-resolution FUSE survey of H2 along 70 sight lines to the Small and Large Magellanic Clouds, using hot stars as background sources. FUSE spectra of 67% of observed Magellanic Cloud sources (52% of LMC and 92% of SMC) exhibit absorption lines from the H2 Lyman and Werner bands between 912 and 1120 A. Our survey is sensitive to N(H2) >= 10^14 cm^-2; the highest column densities are log N(H2) = 19.9 in the LMC and 20.6 in the SMC. We find reduced H2 abundances in the Magellanic Clouds relative to the Milky Way, with average molecular fractions = 0.010 (+0.005, -0.002) for the SMC and = 0.012 (+0.006, -0.003) for the LMC, compared with = 0.095 for the Galactic disk over a similar range of reddening. The dominant uncertainty in this measurement results from the systematic differences between 21 cm radio emission and Lya in pencil-beam sight lines as measures of N(HI). These results imply that the diffuse H2 masses of the LMC and SMC are 8 x 10^6 Msun and 2 x 10^6 Msun, respectively, 2% and 0.5% of the H I masses derived from 21 cm emission measurements. The LMC and SMC abundance patterns can be reproduced in ensembles of model clouds with a reduced H2 formation rate coefficient, R ~ 3 x 10^-18 cm^3 s^-1, and incident radiation fields ranging from 10 - 100 times the Galactic mean value. We find that these high-radiation, low-formation-rate models can also explain the enhanced N(4)/N(2) and N(5)/N(3) rotational excitation ratios in the Clouds. We use H2 column densities in low rotational states (J = 0 and 1) to derive a mean kinetic and/or rotational temperature = 82 +/- 21 K for clouds with N(H2) >= 10^16 cm^-2, similar to Galactic gas. We discuss the implications of this work for theories of star formation in low-metallicity environments. [Abstract abridged]Comment: 30 pages emulateapj, 14 figures (7 color), 7 tables, accepted for publication in the Astrophysical Journal, figures 11 and 12 compressed at slight loss of quality, see http://casa.colorado.edu/~tumlinso/h2/ for full version

Changes in duodenal tissue-associated microbiota following hookworm infection and consecutive gluten challenges in humans with coeliac disease

A reduced diversity of the gastrointestinal commensal microbiota is associated with the development of several inflammatory diseases. Recent reports in humans and animal models have demonstrated the beneficial therapeutic effects of infections by parasitic worms (helminths) in some inflammatory disorders, such as inflammatory bowel disease (IBD) and coeliac disease (CeD). Interestingly, these studies have described how helminths may alter the intestinal microbiota, potentially representing a mechanism by which they regulate inflammation. However, for practical reasons, these reports have primarily analysed the faecal microbiota. In the present investigation, we have assessed, for the first time, the changes in the microbiota at the site of infection by a parasitic helminth (hookworm) and gluten-dependent inflammation in humans with CeD using biopsy tissue from the duodenum. Hookworm infection and gluten exposure were associated with an increased abundance of species within the Bacteroides phylum, as well as increases in the richness and diversity of the tissue-resident microbiota within the intestine, results that are consistent with previous reports using other helminth species in humans and animal models. Hence, this may represent a mechanism by which parasitic helminths may restore intestinal immune homeostasis and exert a therapeutic benefit in CeD, and potentially other inflammatory disorders

Patient-related outcomes in patients referred to a respiratory clinic with persisting symptoms following non-hospitalised COVID-19

Survivors of COVID-19 can present with varied and persisting symptoms, regardless of hospitalisation. We describe the ongoing symptoms, quality of life and return to work status in a cohort of non-hospitalised COVID-19 survivors with persisting respiratory symptoms presenting to clinic, who consented and completed patient-reported outcome measures. We identified fatigue, reduced quality of life and dysregulated breathing alongside the breathlessness. Those with co-existent fatigue had worse mood and quality of life and were less likely to have returned to normal working arrangements compared to those without fatigue. For non-hospitalised people with persisting symptoms following COVID-19 referred to a respiratory assessment clinic, there was a need for a wider holistic assessment, including return to work strategies

Injury, Interiority, and Isolation in Men’s Suicidality

Men’s high suicide rates have been linked to individual risk factors including history of being abused as a child, single marital status, and financial difficulties. While it has also been suggested that the normative influences of hegemonic masculinities are implicated in men’s suicide, the gendered experiences of male suicidality are poorly understood. In the current photovoice study, 20 men who previously had suicidal thoughts, plans, and/or attempts were interviewed as a means to better understanding the connections between masculinities and their experiences of suicidality. The study findings revealed injury, interiority, and isolation as interconnected themes characterizing men’s suicidality. Injury comprised an array of childhood and/or cumulative traumas that fueled men’s ruminating thoughts inhibiting recovery and limiting hopes for improved life quality. In attempting to blunt these traumas, many men described self-injuring through the overuse of alcohol and other drugs. The interiority theme revealed how suicidal thoughts can fuel hopelessness amid summonsing remedies from within. The challenges to self-manage, especially when experiencing muddled thinking and negative thought were evident, and led some participants to summons exterior resources to counter suicidality. Isolation included separateness from others, and was linked to abandonment issues and not having a job and/or partner. Self-isolating also featured as a protection strategy to avoid troubling others and/or reducing exposure to additional noxious stimuli. The study findings suggest multiple intervention points and strategies, the majority of which are premised on promoting men’s social connectedness. The destigmatizing value of photovoice methods is also discussed

Bad influence? – an investigation into the purported negative influence of foreign domestic helpers on children's second language English acquisition

This paper explores the purported negative influence of foreign domestic helpers (FDHs) on child second language acquisition (SLA) by studying Hong Kong Cantonese children's listening ability in second language (L2) English. 31 kindergarten third graders aged 4;6 to 6, and 29 first year secondary students aged 11-14 who have had a Filipino domestic helper at home took part in the study. In addition, 34 youngsters (20 in kindergarten, 14 in secondary) who did not have a Filipino helper participated as controls. Results from two listening tasks (picture choosing task, sound discrimination task) suggest that informants do not differ from the control in their abilities to listen to American-, British-, and Hong Kong English, and that they are better at listening to Filipino-accented English than the control. These findings cast doubts on the anecdotal belief of the harmful effect FDHs have on children's language acquisition including an L2. Moreover, the additional effect of being familiar with another variety of English is arguably a desirable outcome given that English is used as a lingua franca among non-native speakers on a daily basis in this highly globalised world

Lack of an association between gallstone disease and bilirubin levels with risk of colorectal cancer : a Mendelian randomisation analysis

BACKGROUND: Epidemiological studies of the relationship between gallstone disease and circulating levels of bilirubin with risk of developing colorectal cancer (CRC) have been inconsistent. To address possible confounding and reverse causation, we examine the relationship between these potential risk factors and CRC using Mendelian randomisation (MR). METHODS: We used two-sample MR to examine the relationship between genetic liability to gallstone disease and circulating levels of bilirubin with CRC in 26,397 patients and 41,481 controls. We calculated the odds ratio per genetically predicted SD unit increase in log bilirubin levels (ORSD) for CRC and tested for a non-zero causal effect of gallstones on CRC. Sensitivity analysis was applied to identify violations of estimator assumptions. RESULTS: No association between either gallstone disease (P value = 0.60) or circulating levels of bilirubin (ORSD = 1.00, 95% confidence interval (CI) = 0.96-1.03, P value = 0.90) with CRC was shown. CONCLUSIONS: Despite the large scale of this study, we found no evidence for a causal relationship between either circulating levels of bilirubin or gallstone disease with risk of developing CRC. While the magnitude of effect suggested by some observational studies can confidently be excluded, we cannot exclude the possibility of smaller effect sizes and non-linear relationships.Peer reviewe