The Unreasonable Effectiveness of Contact Tracing on Networks with Cliques

Contact tracing, the practice of isolating individuals who have been in contact with infected individuals, is an effective and practical way of containing disease spread. Here, we show that this strategy is particularly effective in the presence of social groups: Once the disease enters a group, contact tracing not only cuts direct infection paths but can also pre-emptively quarantine group members such that it will cut indirect spreading routes. We show these results by using a deliberately stylized model that allows us to isolate the effect of contact tracing within the clique structure of the network where the contagion is spreading. This will enable us to derive mean-field approximations and epidemic thresholds to demonstrate the efficiency of contact tracing in social networks with small groups. This analysis shows that contact tracing in networks with groups is more efficient the larger the groups are. We show how these results can be understood by approximating the combination of disease spreading and contact tracing with a complex contagion process where every failed infection attempt will lead to a lower infection probability in the next attempts. Our results illustrate how contract tracing in real-world settings can be more efficient than predicted by models that treat the system as fully mixed or the network structure as locally tree-like.Comment: 15 pages, 13 figures, 4 table

Dissemination as cultivation: scholarly communications in a digital age

Participatory web platforms have greatly enhanced the means by which students, scholars, and practitioners engage in arts and humanities research. Intuitive interfaces and content delivery systems have brought about paradigm shifts in the ways in which scholars connect and communicate, removing the need for advanced technical expertise when conducting a range of scholarly activities. Collaborative networks of both research and communications are now facilitated across ubiquitous systems that interact to form a transdisciplinary and dynamic interconnection of thought and practice. This chapter introduces readers to the underlying principles of scholarly communications and publishing in the digital age, uncovering the affordances and limitations of online public scholarship. The relationship between form and content is discussed, drawing upon relevant case studies to demonstrate how scholars should consider cultivating the habits and practices of thick collegiality. From here, an overview of relevant platforms is offered, before strategies for social media are detailed, all of which are supplemented by this chapter’s corresponding electronic materials

Removal of dissolved oxygen interference in the amperometric detection of monochloramine using a pH control method

Monochloramine amperometric determination was investigated using a pH control method to eliminate dissolved oxygen as an interferent. This method allowed local pH conditions to become more acidic, causing the production of dichloramine. This species showed an onset of electro-reduction at 450 mV, far outside of the oxygen reduction region. Monochloramine was calibrated using this method and showed good linearity (0.99) and a limit of detection of 0.03 ppm

The use of inline high-shear rotor-stator mixing for preparation of high-solids milk-protein-stabilised oil-in-water emulsions with different protein:fat ratios

The emulsification of refined palm oil (RPO) in a continuous phase consisting of skim milk concentrate (SMC) and maltodextrin with a dextrose equivalent value of 17 (MD17) to produce fat-filled milk emulsions (FFMEs), was studied. A novel inline high-shear mixing (IHSM) method was used to produce emulsions, and three protein contents were investigated at a fixed RPO content of 12%: low (7.7%), medium (10.5%) and high (13%). Pressure drop measurement was used as an inline approach to determine viscosity using the Hagen-Poiseuille equation. In addition, offline viscometry, particle size and emulsion stability analyses were performed. Emulsion fat droplet size decreased significantly (P < 0.05) as a function of number of passes through the IHSM, due to an effective increase in residence time. Furthermore, inline pressure drop data demonstrated that the emulsification process displayed two distinct stages: (i) oil injection, and (ii) reduction in fat droplet size, irrespective of protein content

Stunning and Right Ventricular Dysfunction Is Induced by Coronary Balloon Occlusion and Rapid Pacing in Humans: Insights From Right Ventricular Conductance Catheter Studies

BACKGROUND: We sought to determine whether right ventricular stunning could be detected after supply (during coronary balloon occlusion [BO]) and supply/demand ischemia (induced by rapid pacing [RP] during transcatheter aortic valve replacement) in humans. METHODS AND RESULTS: Ten subjects with single-vessel right coronary artery disease undergoing percutaneous coronary intervention with normal ventricular function were studied in the BO group. Ten subjects undergoing transfemoral transcatheter aortic valve replacement were studied in the RP group. In both, a conductance catheter was placed into the right ventricle, and pressure volume loops were recorded at baseline and for intervals over 15 minutes after a low-pressure BO for 1 minute or a cumulative duration of RP for up to 1 minute. Ischemia-induced diastolic dysfunction was seen 1 minute after RP (end-diastolic pressure [mm Hg]: 8.1±4.2 versus 12.1±4.1, P<0.001) and BO (end-diastolic pressure [mm Hg]: 8.1±4.0 versus 8.7±4.0, P=0.03). Impairment of systolic and diastolic function after BO remained at 15-minutes recovery (ejection fraction [%]: 55.7±9.0 versus 47.8±6.3, P<0.01; end-diastolic pressure [mm Hg]: 8.1±4.0 versus 9.2±3.9, P<0.01). Persistent diastolic dysfunction was also evident in the RP group at 15-minutes recovery (end-diastolic pressure [mm Hg]: 8.1±4.1 versus 9.9±4.4, P=0.03) and there was also sustained impairment of load-independent indices of systolic function at 15 minutes after RP (end-systolic elastance and ventriculo-arterial coupling [mm Hg/mL]: 1.25±0.31 versus 0.85±0.43, P<0.01). CONCLUSIONS: RP and right coronary artery balloon occlusion both cause ischemic right ventricular dysfunction with stunning observed later during the procedure. This may have intraoperative implications in patients without right ventricular functional reserve

Monitoring of pilot-scale induction processes for dairy powders using inline and offline approaches

The induction of two dairy powders, skim milk powder (SMP; low-protein content), and milk protein isolate (MPI, high-protein content), was studied. The powder induction approaches investigated were (1) eductor alone, (2) eductor with a static mixer, and (3) eductor with high shear inline mixing. Measurement of pressure drop, from which viscosity was determined inline using the Hagen-Poiseuille equation, offline viscometry and particle size analyses were performed. High shear inline mixing provided the most efficient induction of powders. In addition, more rapid powder induction, as observed from particle size analysis, was achieved for SMP in comparison to MPI, owing to its better rehydration properties. Inline pressure drop data demonstrated that dissolution of MPI had two distinct phases: (i) powder introduction, and (ii) powder breakdown, irrespective of configuration and concentration employed

Marked elevation in plasma osteoprotegerin constitutes an early and consistent feature of cerebral malaria

Adherence of infected erythrocytes to vascular endothelium causes acute endothelial cell (EC) activation during Plasmodium falciparum infection. Consequently, proteins stored in Weibel-Palade (WP) bodies within EC are secreted into the plasma. Osteoprotegerin (OPG) binds to VWF and consequently is stored within WP bodies. Given the critical role of EC activation in the pathogenesis of severe malaria, we investigated plasma OPG levels in children with P. falciparum malaria. At presentation, plasma OPG levels were significantly elevated in children with cerebral malaria (CM) compared to healthy controls (means 16.0 vs 0.8 ng/ml; p<0.01). Importantly, OPG levels were also significantly higher in children with CM who had a fatal outcome, compared to children with CM who survived. Finally, in children with CM, plasma OPG levels correlated with other established prognostic indices (including plasma lactate levels and peripheral parasite density). To further investigate the relationship between severe malaria and OPG, we utilised a murine model of experimental CM in which C57BL/6J mice were infected with P. berghei ANKA. Interestingly, plasma OPG levels were increased 4.6 fold within 24 hours following P. berghei inoculation. This early marked elevation in OPG levels was observed before any objective clinical signs were apparent, and preceded the development of peripheral blood parasitaemia. As the mice became increasingly unwell, plasma OPG levels progressively increased. Collectively, these data suggest that OPG constitutes a novel biomarker with prognostic significance in patients with severe malaria. In addition, further studies are required to determine whether OPG plays a role in modulating malaria pathogenesis

Randomized Interventional Study on Prediction of Preeclampsia/Eclampsia in Women With Suspected Preeclampsia: INSPIRE.

The ratio of maternal serum sFlt-1 (soluble fms-like tyrosine kinase 1) to PlGF (placental growth factor) has been used retrospectively to rule out the occurrence of preeclampsia, a pregnancy hypertensive disorder, within 7 days in women presenting with clinical suspicion of preeclampsia. A prospective, interventional, parallel-group, randomized clinical trial evaluated the use of sFlt-1/PlGF ratio in women presenting with suspected preeclampsia. Women were assigned to reveal (sFlt-1/PlGF result known to clinicians) or nonreveal (result unknown) arms. A ratio cutoff of 38 was used to define low (≤38) and elevated risk (>38) of developing the condition in the subsequent week. The primary end point was hospitalization within 24 hours of the test. Secondary end points were development of preeclampsia and other adverse maternal-fetal outcomes. We recruited 370 women (186 reveal versus 184 nonreveal). Preeclampsia occurred in 85 women (23%). The number of admissions was not significantly different between groups (n=48 nonreveal versus n=60 reveal; P=0.192). The reveal trial arm admitted 100% of the cases that developed preeclampsia within 7 days, whereas the nonreveal admitted 83% (P=0.038). Use of the test yielded a sensitivity of 100% (95% CI, 85.8-100) and a negative predictive value of 100% (95% CI, 97.1-100) compared with a sensitivity of 83.3 (95% CI, 58.6-96.4) and negative predictive value of 97.8 (95% CI, 93.7-99.5) with clinical practice alone. Use of the sFlt-1/PlGF ratio significantly improved clinical precision without changing the admission rate. Clinical Trial Registration- URL: http://www.isrctn.com. Unique identifier: ISRCTN87470468