Probable Secondary Infections in Households of SARS Patients in Hong Kong

Although severe acute respiratory syndrome (SARS) is highly infectious in clinical settings, SARS has not been well examined in household settings. The household and household member attack rates were calculated for 1,214 SARS case-patients and their household members, stratified by two phases of the epidemic. A case-control analysis identified risk factors for secondary infection. Secondary infection occurred in 14.9% (22.1% versus 11% in earlier and later phases) of all households and 8% (11.7% versus 5.9% in the earlier and later phases) of all household members. Healthcare workers’ households were less likely to be affected. Risk factors from the multivariate analysis included at-home duration before hospitalization, hospital visitation to the SARS patient (and mask use during the visit), and frequency of close contact. SARS transmission at the household level was not negligible in Hong Kong. Transmission rates may be greatly reduced with precautionary measures taken by household members of SARS patients

Active contractility in actomyosin networks

Contractile forces are essential for many developmental processes involving cell shape change and tissue deformation. Recent experiments on reconstituted actomyosin networks, the major component of the contractile machinery, have shown that active contractility occurs above a threshold motor concentration and within a window of crosslink concentration. We present a microscopic dynamic model that incorporates two essential aspects of actomyosin self-organization: the asymmetric load response of individual actin filaments and the correlated motor-driven events mimicking myosin-induced filament sliding. Using computer simulations we examine how the concentration and susceptibility of motors contribute to their collective behavior and interplay with the network connectivity to regulate macroscopic contractility. Our model is shown to capture the formation and dynamics of contractile structures and agree with the observed dependence of active contractility on microscopic parameters including the contractility onset. Cooperative action of load-resisting motors in a force-percolating structure integrates local contraction/buckling events into a global contractile state via an active coarsening process, in contrast to the flow transition driven by uncorrelated kicks of susceptible motors.Comment: 15 pages, 4 main figures, 4 supplementary figure

Potential roles of masculine role discrepancy, discrepancy stress, and self-esteem in affecting addictive use of social networking sites among Chinese men: A random population-based study

Background and aims Masculine role discrepancy (i.e., men perceiving themselves not living up to the ideal manhood and being less masculine than the typical “man”) and related discrepancy stress were associated with some risk behaviors. No study has looked at their relationships with addictive use of social networking sites (SNSs), an emerging potential public health concern. The study constructed a moderated mediation model to test whether masculine role discrepancy would be positively associated with discrepancy stress, which would, in turn, be positively associated with addictive use of SNS, and whether self-esteem would buffer (moderate) the association between masculine role discrepancy and discrepancy stress. Methods A random population-based cross-sectional telephone survey interviewed 2,000 Hong Kong male adults in the general population. Results Currently unmarried and non-cohabiting, younger, and better educated participants reported higher addictive use of SNS scores than others. Adjusted for these variables, masculine role discrepancy and discrepancy stress were positively associated, and self-esteem was negatively associated with addictive use of SNS scores. Path analysis indicated that masculine role discrepancy was associated with addictive use of SNS through discrepancy stress (mediation); self-esteem buffered (moderated) the association between masculine role discrepancy and discrepancy stress; self-esteem was not significantly associated with addictive use of SNS in this model with good fit. Discussion The findings support the general strain theory’s postulation that strain is associated with stress, which is in turn associated with addictive use of SNS sites. Implications, potential interventions, and future studies are discussed in this study

Internal representation and factional faultlines as antecedents for board performance in social enterprises

There is an increasing scholarly interest in how social enterprises manage their hybrid nature. As hybrid organizational forms, social enterprises combine mission-driven social goals and revenue generating activities in a variety of organizational constellations and in diverse institutional contexts. Acknowledging the potentially conflicting demands that institutional environments impose on social enterprises there is an increasing research interest in the existence and proliferation of these conflicting demands at the organizational level. Some researchers have pointed to the importance of particular management practices and governance characteristics – such as authority relations and internal representation – as mechanisms to deal with the conflicting demands at the organizational level. This paper adds to this stream of literature by taking into account the organizational level dynamics of internal representation and the proliferation of factional groups in the boards of directors of hybrid organizational forms and their impact on board performance, ultimately influencing the organizational performance

Emotional Distress, Alcohol Use, and Bidirectional Partner Violence Among Lesbian Women

This study examined the relationship between emotional distress (defined as depression, brooding, and negative affect), alcohol outcomes, and bidirectional intimate partner violence among lesbian women. Results lend support to the self-medication hypothesis, which predicts that lesbian women who experience more emotional distress are more likely to drink to cope, and in turn report more alcohol use, problem drinking, and alcohol-related problems. These alcohol outcomes were, in turn, associated with bidirectional partner violence (BPV). These results offer preliminary evidence that, similar to findings for heterosexual women, emotional distress, alcohol use, and particularly, alcohol-related problems are risk factors for BPV among lesbian women

Maternal cardiac output and fetal doppler predict adverse neonatal outcomes in pregnant women with heart disease

Background-The mechanistic basis of the proposed relationship between maternal cardiac output and neonatal complications in pregnant women with heart disease has not been well elucidated. Methods and Results-Pregnant women with cardiac disease and healthy pregnant women (controls) were prospectively followed with maternal echocardiography and obstetrical ultrasound scans at baseline, third trimester, and postpartum. Fetal/neonatal complications (death, small-for-gestational-age or low birthweight, prematurity, respiratory distress syndrome, or intraventricular hemorrhage) comprised the primary study outcome. One hundred and twenty-seven women with cardiac disease and 45 healthy controls were enrolled. Neonatal events occurred in 28 pregnancies and were more frequent in the heart disease group as compared with controls (n=26/127 or 21% versus n=2/45 or 4%; P=0.01). Multiple complications in an infant were counted as a single outcome event. Neonatal complications in the heart disease group were small-for-gestational-age/low birthweight (n=18), prematurity (n=14), and intraventricular hemorrhage/respiratory distress syndrome (n=5). Preexisting obstetric risk factors (P=0.003), maternal cardiac output decline from baseline to third trimester (P=0.017), and third trimester umbilical artery Doppler abnormalities (P \u3c 0.001) independently predicted neonatal complications and were incorporated into a novel risk index in which 0, 1, and \u3e 1 predictor corresponded to expected complication rates of 5%, 30%, and 76%, respectively. Conclusions-Decline in maternal cardiac output during pregnancy and abnormal umbilical artery Doppler flows independently predict neonatal complications. These findings will enhance the identification of higher risk pregnancies that would benefit from close antenatal surveillance

Multiple Particle Tracking and Two-Point Microrheology in Cells

Mechanical stress and stiffness are increasingly recognized to play important roles in numerous cell biological processes, notably cell differentiation and tissue morphogenesis. Little definite is known, however, about how stress propagates through different cell structures or how it is converted to biochemical signals via mechanotransduction, due in large part to the difficulty of interpreting many cell mechanics experiments. A newly developed technique, two-point microrheology (TPM), can provide highly interpretable, quantitative measurements of cells’ frequency-dependent shear moduli and spectra of their fluctuating intracellular stresses. TPM is a non-invasive method based on measuring the Brownian motion of large numbers of intracellular particles using multiple particle tracking. While requiring only hardware available in many cell biology laboratories–a phase microscope and digital video camera, as a statistical technique, it also requires the automated analysis of many thousands of micrographs. Here we describe in detail the algorithms and software tools used for such large-scale multiple particle tracking, as well as common sources of error and the microscopy methods needed to minimize them. Moreover, we describe the physical principles behind TPM and other passive microrheology methods, their limitations, and typical results for cultured epithelial cells

Illness representation of COVID-19 affected public’s support and anticipated panic regarding the living with the virus policy: a cross-sectional study in a Chinese general population

BackgroundThere is a global trend for countries to adopt the Living with the Virus (LWV) policy regarding COVID-19. Little is known about the public’s supportiveness and emotional responses (e.g., anticipated panic) related to this policy. Such responses may be associated with illness representations of COVID-19 (i.e., how people think and feel about COVID-19). This novel topic was investigated in this study to facilitate policy-making and health communication.MethodsA random, population-based telephone survey interviewed 500 adults aged ≥18 of the Hong Kong general adult population from March to April 2022.ResultsThe prevalence of the public’s support and anticipated panic regarding the LWV policy, which were negatively correlated with each other, was 39.6 and 24.2%, respectively. The illness representation constructs of consequences, timeline, identity, illness concern, and emotional representations were negatively associated with supportiveness and positively associated with anticipated panic regarding the LWV policy. Illness coherence was significantly associated with policy support but not with anticipated panic. The associations between personal control/treatment control and supportiveness/anticipated panic were statistically non-significant. Moderation analyses showed that the above significant associations were invariant between those with and without previous COVID-19 infection.ConclusionPolicymakers need to be sensitized about the public’s supportive/unsupportive attitude and potential worry (panic) when adopting the LWV policy. Such attitudes/emotional responses may be affected by people’s illness representations of COVID-19. In general, those who found COVID-19 involving a milder nature and less negative emotions would be more supportive and anticipated less panic under the LWV policy

Actin-driven cell dynamics probed by Fourier transform light scattering

We applied the newly developed Fourier transform light scattering (FTLS) to study dynamic light scattering in single live cells, at a temporal scale of seconds to hours. The nanoscale cell fluctuations were measured with and without the active actin contribution. We found experimentally that the spatio-temporal signals rendered by FTLS reveal interesting cytoskeleton dynamics in glial cells (the predominant cell type in the nervous system). The active contribution of actin cytoskeleton was obtained by modulating its dynamic properties via Cytochalasin-D, a drug that inhibits actin polymerization/depolymerization

Intracellular microrheology of motile Amoeba proteus

The motility of motile Amoeba proteus was examined using the technique of passive particle tracking microrheology, with the aid of newly-developed particle tracking software, a fast digital camera and an optical microscope. We tracked large numbers of endogeneous particles in the amoebae, which displayed subdiffusive motion at short time scales, corresponding to thermal motion in a viscoelastic medium, and superdiffusive motion at long time scales due to the convection of the cytoplasm. Subdiffusive motion was characterised by a rheological scaling exponent of 3/4 in the cortex, indicative of the semiflexible dynamics of the actin fibres. We observed shear-thinning in the flowing endoplasm, where exponents increased with increasing flow rate; i.e. the endoplasm became more fluid-like. The rheology of the cortex is found to be isotropic, reflecting an isotropic actin gel. A clear difference was seen between cortical and endoplasmic layers in terms of both viscoelasticity and flow velocity, where the profile of the latter is close to a Poiseuille flow for a Newtonian fluid