Do-It-Yourself Low-Cost Stroboscopy

This case series tests the construction of an extremely low-cost stroboscope and assesses its strengths and weaknesses.

Hemotympanum as a Complication of a Valsalva Maneuver during Childbirth

Background

Hemotympanum may occur due to otic barotrauma secondary to Valsalva maneuver during the second phase of labor. A pressure differential across the tympanic membrane (TM) of about five psi can cause rupture. The increased intrathoracic and intraabdominal pressure spikes repeatedly manifested by "pushing" during second-stage labor easily approach (and may exceed) this level. Clinical Presentation. This case report describes a healthy thirty-seven-year-old multipara patient admitted for the 40-weeks' gestational age routine follow-up that proceeded to active labor followed by an aural fullness and bloody otorrhea. Otoscopic examination with a light microscope confirmed the hemotympanum of the right tympanic membrane.

Conclusion

Forceful Valsalva can cause hemotympanum. Investigating the benefits and disadvantages of the pushing methods could help reduce such complications in the future. A prompt evaluation of an otolaryngologist should be requested in the event of a new postpartum hearing disturbance or bloody otorrhea.

Outcomes of the Bethesda system for reporting thyroid cytopathology in community- vs. institution-performed cytology

OBJECTIVES

Despite the important role of the community in the assessment and risk stratification of patients with thyroid nodules, evidence-based data on the Bethesda System for Reporting Thyroid Cytopathology (BSRTC) performance in community clinics is lacking. We aim to evaluate BSRTC performance of aspirations taken in community clinics compared with primary referral center.

METHODS

Patients who underwent thyroid surgery between 2013 and 2018 at our institution were divided according to the fine needle aspirations (FNA) settings: community FNA (cFNA) vs. institutional FNA (iFNA). Demographics, BSRTC results and final pathology were collected. Diagnostic values were calculated for BSRTC categories (sensitivity, specificity, positive predictive value [PPV], and negative predictive value [NPV]), and were compared between the groups.

RESULTS

A total of 268 nodules were included in the study; 77% (207) cFNA and 23% (61) iFNA. Patients in the community were younger (51.7 ± 15.1 vs. 56.6 years±14.8, p = 0.03) and with less epidemiology risk factors for thyroid cancer (1.9% vs 13.1%, p < 0.001). cFNA malignancy rate for BSRTC I-VI was 0%, 6.4%, 11.8%, 32.1%, 91.6% and 93.8% respectively. Best sensitivity was found for BSRTC III-VI in both groups (88% and 83%, cFNAs and iFNAs, respectively). Overall best performance was obtained for BSRTC V-VI for both groups (cfNA: 85%, 97%, 93%, 94% and 93%; iFNAs: 81%, 100%, 100%, 87% and 91%, for sensitivity, specificity, PPV, NPV and accuracy, respectively).

CONCLUSIONS

Community-performed FNAs demonstrate acceptable BSRTC distribution and malignancy rates, comparable with a primary referral academic hospital. This supports the universality of the BSRTC 2017 and its recommendations also in the community.

Effect of helicity and rotation on the free decay of turbulent flows

The self-similar decay of energy in a turbulent flow is studied in direct numerical simulations with and without rotation. Two initial conditions are considered: one nonhelical (mirror symmetric) and one with maximal helicity. While in the absence of rotation the energy in the helical and nonhelical cases decays with the same rate, in rotating flows the helicity content has a major impact on the decay rate. These differences are associated with differences in the energy and helicity cascades when rotation is present. The properties of the structures in the flow at late times are also discussed.

Community structures and role detection in music networks

We analyze the existence of community structures in two different social networks using data obtained from similarity and collaborative features between musical artists. Our analysis reveals some characteristic organizational patterns and provides information about the driving forces behind the growth of the networks. In the similarity network, we find a strong correlation between clusters of artists and musical genres. On the other hand, the collaboration network shows two different kinds of communities: rather small structures related to music bands and geographic zones, and much bigger communities built upon collaborative clusters with a high number of participants related through the period the artists were active. Finally, we detect the leading artists inside their corresponding communities and analyze their roles in the network by looking at a few topological properties of the nodes.