Crystallization kinetics: A solution for geometrical impingement

Starting from the wrong derivation by Erukhimovitch and Baram of an equation alternative to the classical Kolmogoroff-Johnson-Mehl-Avrami one for the transformed fraction in an infinite specimen, undergoing an isothermal first-order phase transformation, it is shown that a different exact solution of the geometrical problem of impingement can be obtained. Such solution is equivalent to the empirical one already presented by Austin and Rickett more than sixty years ago and allows to better fit experimental results for isothermal transformations. This also suggests that perhaps different statistical derivations could allow to reach the same result.651

Pharmacological treatment of ceftriaxone-related cholelithiasis in children: is it worthwhile?

Ceftriaxone treatment of bacterial infections can be associated with biliary complications, more commonly in children than adults, in a dosedependent manner. This study describes a clinical case series of children with ceftriaxone-related cholelithiasis. We performed a retrospective analysis of cases of ceftriaxone-related biliary complications admitted to the Pediatric Clinic, Department of Clinical and Experimental Medicine, University of Sassari, Italy, during the period 2005-2015. Four children with cholelithiasis occurring during, or soon after, the treatment with ceftriaxone are reported. Case 1 (6-month-old), case 2 (9-yearold) and case 4 (10-year-old) were symptomatic, while case 3 (3-year-old) was asymptomatic. After the ultrasonographic diagnosis of gallstones (cases 1 and 2) or biliary sludge (cases 3 and 4), ceftriaxone treatment was withdrawn, and ursodeoxycholic acid (UDCA) was started in cases 1 and 2. A complete recovery was observed in all but case 1, in whom cholelithiasis was still detectable at one-year follow-up by ultrasonography. This case underwent a triple antibiotic protocol for bacterial meningitis. The protocol included rifampicin, which is known to have an effect in decreasing hepatic concentration of bile salts. Therefore, in this case, both rifampicin and UDCA were of no benefit in preventing or treating ceftriaxone biliary complications. The current pharmacological approach for the treatment of ceftriaxonerelated cholelithiasis seems to be ineffective, likely due to the high calcium content of gallstones. Therefore, the best strategy of intervention for ceftriaxone biliary complications in children remains the prevention of the risk factors

Snoring in Portuguese primary school children

OBJECTIVE: To determine the prevalence of snoring and its potential associations with sleep problems, such as daytime symptoms, medical conditions, school performance, and behavioral disturbances in Portuguese children attending primary school. METHODS: A previously validated questionnaire was sent to the parents of 1381 children attending primary schools in a parish of Coimbra, Portugal. To assess behavioral disturbances, the Portuguese version of Rutter's Children's Behavior Questionnaire for completion by teachers was used. RESULTS: Of the 988 questionnaires returned (71.5%), complete information concerning snoring was obtained for 976 children (496 girls and 480 boys; mean age: 8.1 +/- 1.5 years). Loud snoring during sleep was reported as frequent or constantly present (LSn) in 84 children (8.6%), as occasionally present in 299 children (30.6%), and as never present (NSn) by 593 children (60.8%). The LSn and NSn groups did not differ with respect to age, gender, sleep duration, time to fall asleep, frequency of night wakings, bedwetting, daytime tiredness, and school achievement. However, LSn was significantly associated with increased bedtime problems (fears and struggles), increased need for comforting activities to fall asleep, behaviors suggestive of parasomnias (sleep talking, teeth grinding, and night terrors), increased daytime sleepiness and irritability, and behavioral disturbances. Children in the LSn group were also more likely to report recurrent medical problems particularly those involving infections of the respiratory tract. CONCLUSIONS: Snoring is a common symptom in Portuguese children that is associated with behavioral daytime and sleep time disturbances. Children with loud snoring may benefit from early evaluation and intervention

Variations of training load, monotony, and strain and dose-response relationships with maximal aerobic speed, maximal oxygen uptake, and isokinetic strength in professional soccer players

This study aimed to identify variations in weekly training load, training monotony, and training strain across a 10-week period (during both, pre- and in-season phases); and to analyze the dose-response relationships between training markers and maximal aerobic speed (MAS), maximal oxygen uptake, and isokinetic strength. Twenty-seven professional soccer players (24.9±3.5 years old) were monitored across the 10-week period using global positioning system units. Players were also tested for maximal aerobic speed, maximal oxygen uptake, and isokinetic strength before and after 10 weeks of training. Large positive correlations were found between sum of training load and extension peak torque in the right lower limb (r = 0.57, 90%CI[0.15;0.82]) and the ratio agonist/antagonist in the right lower limb (r = 0.51, [0.06;0.78]). It was observed that loading measures fluctuated across the period of the study and that the load was meaningfully associated with changes in the fitness status of players. However, those magnitudes of correlations were small-to-large, suggesting that variations in fitness level cannot be exclusively explained by the accumulated load and loading profile

Barbed suture vs conventional tenorrhaphy: biomechanical analysis in an animal model.

BACKGROUND: The advantages of barbed suture for tendon repair could be to eliminate the need for a knot and to better distribute the load throughout the tendon so as to reduce the deformation at the repair site. The purpose of this study was to evaluate the breaking force and the repair site deformation of a new barbed tenorrhaphy technique in an animal model. MATERIALS AND METHODS: Sixty porcine flexor tendons were divided randomly into three groups and repaired with one of the following techniques: a new 4-strand barbed technique using 2/0 polypropylene Quill™ SRS or 2/0 polydioxanone Quill™ SRS and a modified Kessler technique using 3/0 prolene. All tendons underwent mechanical testing to assess the 2-mm gap formation force, the breaking force and the mode of failure. The percentage change in tendon cross-sectional area before and after repair was calculated. RESULTS: The two-sample Student t-test demonstrated a significant increase in 2-mm gap formation force and in breaking force with barbed sutures, independently from suture material, when compared to traditional Kessler suture. Concerning the tendon profile, we registered less bunching at the repair site in the two barbed groups compared with the Kessler group. CONCLUSIONS: This study confirms the promising results achieved in previous ex vivo studies about the use of barbed suture in flexor tendon repair. In our animal model, tenorrhaphy with Quill™ SRS suture guarantees a breaking force of repair that exceeds the 40-50 N suggested as sufficient to initiate early active motion, and a smoother profile at the repair site. LEVEL OF EVIDENCE: Not applicable

Telepresence and the Role of the Senses

The telepresence experience can be evoked in a number of ways. A well-known example is a player of videogames who reports about a telepresence experience, a subjective experience of being in one place or environment, even when physically situated in another place. In this paper we set the phenomenon of telepresence into a theoretical framework. As people react subjectively to stimuli from telepresence, empirical studies can give more evidence about the phenomenon. Thus, our contribution is to bridge the theoretical with the empirical. We discuss theories of perception with an emphasis on Heidegger, Merleau-Ponty and Gibson, the role of the senses and the Spinozian belief procedure. The aim is to contribute to our understanding of this phenomenon. A telepresence-study that included the affordance concept is used to empirically study how players report sense-reactions to virtual sightseeing in two cities. We investigate and explore the interplay of the philosophical and the empirical. The findings indicate that it is not only the visual sense that plays a role in this experience, but all senses

Socioeconomic risk markers of arthropod-borne virus (arbovirus) infections: a systematic literature review and meta-analysis.

INTRODUCTION: Arthropod-borne viruses (arboviruses) are of notable public health importance worldwide, owing to their potential to cause explosive outbreaks and induce debilitating and potentially life-threatening disease manifestations. This systematic review and meta-analysis aims to assess the relationship between markers of socioeconomic position (SEP) and infection due to arboviruses with mosquito vectors. METHODS: We conducted a systematic search on PubMed, Embase, and LILACS databases to identify studies published between 1980 and 2020 that measured the association of SEP markers with arbovirus infection. We included observational studies without geographic location or age restrictions. We excluded studies from grey literature, reviews and ecological studies. Study findings were extracted and summarised, and pooled estimates were obtained using random-effects meta-analyses. RESULTS: We identified 36 observational studies using data pertaining to 106 524 study participants in 23 geographic locations that empirically examined the relationship between socioeconomic factors and infections caused by seven arboviruses (dengue, chikungunya, Japanese encephalitis, Rift Valley fever, Sindbis, West Nile and Zika viruses). While results were varied, descriptive synthesis pointed to a higher risk of arbovirus infection associated with markers of lower SEP, including lower education, income poverty, low healthcare coverage, poor housing materials, interrupted water supply, marital status (married, divorced or widowed), non-white ethnicities and migration status. Pooled crude estimates indicated an increased risk of arboviral infection associated with lower education (risk ratio, RR 1.5 95% CI 1.3 to 1.9); I2=83.1%), interruption of water supply (RR 1.2; 95% CI 1.1 to 1.3; I2=0.0%) and having been married (RR 1.5 95% CI 1.1 to 2.1; I2=85.2%). CONCLUSION: Evidence from this systematic review suggests that lower SEP increases the risk of acquiring arboviral infection; however, there was large heterogeneity across studies. Further studies are required to delineate the relationship between specific individual, household and community-level SEP indicators and arbovirus infection risks to help inform targeted public health interventions. PROSPERO REGISTRATION NUMBER: CRD42019158572

Calculating the energy spectra of magnetic molecules: application of real- and spin-space symmetries

The determination of the energy spectra of small spin systems as for instance given by magnetic molecules is a demanding numerical problem. In this work we review numerical approaches to diagonalize the Heisenberg Hamiltonian that employ symmetries; in particular we focus on the spin-rotational symmetry SU(2) in combination with point-group symmetries. With these methods one is able to block-diagonalize the Hamiltonian and thus to treat spin systems of unprecedented size. In addition it provides a spectroscopic labeling by irreducible representations that is helpful when interpreting transitions induced by Electron Paramagnetic Resonance (EPR), Nuclear Magnetic Resonance (NMR) or Inelastic Neutron Scattering (INS). It is our aim to provide the reader with detailed knowledge on how to set up such a diagonalization scheme.Comment: 29 pages, many figure