Flow and particle deposition using an integrated CFD model of the respiratory system

This paper was presented at the 3rd Micro and Nano Flows Conference (MNF2011), which was held at the Makedonia Palace Hotel, Thessaloniki in Greece. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, Aristotle University of Thessaloniki, University of Thessaly, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute.In the present study a theoretical investigation on flow, particle motion, and deposition in the respiratory system is reported. An integrated computational model of the respiratory system is developed comprised of nine sequential computational blocks corresponding to the nasal cavity, the pharyngo-trachea, and a series of branches of the pulmonary system. Airflow during steady-state inhalation inside the human respiratory system was determined using computational fluid dynamics (CFD) for inlet velocities, vin = 1-20 m/s, corresponding to inhalation flow rates of 9 to 180 L/min, and particle deposition was examined in detail for particle sizes, D=1-20μm. Local deposition efficiencies as well as spatial distribution of deposited particles were found to be strongly dependent on the particle size and volumetric flow rate

Sickness Absence in the Private Sector of Greece: Comparing Shipyard Industry and National Insurance Data

Approximately 3% of employees are absent from work due to illness daily in Europe, while in some countries sickness absence exceeds 20 days per year. Based on a limited body of reliable studies, Greek employees in the private sector seem to be absent far less frequently (<5 days/year) compared to most of the industrialized world. The aim of this study was to estimate the levels of sickness absence in the private sector in Greece, using shipyard and national insurance data. Detailed data on absenteeism of employees in a large shipyard company during the period 1999–2006 were utilized. National data on compensated days due to sickness absence concerning all employees (around 2 million) insured by the Social Insurance Institute (IKA, the largest insurance scheme in Greece) were retrieved from the Institute’s annual statistical reports for the period 1987–2006. Sick-leave days per employee and sick-leave rate (%) were calculated, among other indicators. In the shipyard cohort, the employment time loss due to sick leave was 1%. The mean number of sick-leave days per employee in shipyards ranged between 4.6 and 8.7 and sick-leave rate (sickness absenteeism rate) varied among 2% and 3.7%. The corresponding indicators for IKA were estimated between 5 and 6.3 sick-leave days per insured employee (median 5.8), and 2.14–2.72% (median 2.49%), respectively. Short sick-leave spells (<4 days) may account at least for the 25% of the total number of sick-leave days, currently not recorded in national statistics. The level of sickness absence in the private sector in Greece was found to be higher than the suggested by previous reports and international comparative studies, but still remains one of the lowest in the industrialized world. In the 20-years national data, the results also showed a 7-year wave in sickness absence indexes (a decrease during the period 1991–1997 and an increase in 1998–2004) combined with a small yet significant decline as a general trend. These observations deserve detailed monitoring and could only partly be attributed to the compensation and unemployment rates in Greece so other possible reasons should be explored

Case report: hydroquinone and/or glutaraldehyde induced acute myeloid leukaemia?

BACKGROUND: Exposures to high doses of irradiation, to chemotherapy, benzene, petroleum products, paints, embalming fluids, ethylene oxide, herbicides, pesticides, and smoking have been associated with an increased risk of acute myelogenous leukemia (AML). Although there in no epidemiological evidence of relation between X-ray developer, fixer and replenisher liquids and AML, these included glutaraldehyde which has weakly associated with lymphocytic leukemia in rats and hydroquinone has been increasingly implicated in producing leukemia, causing DNA and chromosomal damage, inhibits topo-isomerase II, alter hematopoiesis and inhibit apoptosis of neoplastic cells. CASE PRESENTATION: Two white females (A and B) hired in 1985 as medical radiation technologists in a primary care center, in Greece. In July 2001, woman A, 38-years-old, was diagnosed as having acute monocytic leukaemia (FAB M5). The patient did not respond to therapy and died threeweeks later. In August 2001, woman B, 35-year-old, was diagnosed with acute promyelocytic leukaemia (FAB M3). Since discharge, she is in continuous complete remission. Both women were non smokers without any medical history. Shortly after these incidents official inspectors and experts inspected workplace, examined equipment, archives of repairs, notes, interviewed and monitored employees. They concluded that shielding was inadequate for balcony's door but personal monitoring did not show any exceeding of TLV of 20 mSv yearly and cytogenetics analysis did not reveal findings considered to be characteristics of ionizing exposure. Equipment for developing photos had a long list of repairs, mainly leakages of liquids and increases of temperature. On several occasions the floor has been flooded especially during 1987–1993 and 1997–2001. Inspection confirmed a complete lack of ventilation and many spoiled medical x-ray films. Employees reported that an "osmic" level was continuously evident and frequently developed symptoms of respiratory irritation and dizziness. CONCLUSION: The findings support the hypothesis that the specific AML cases might have originated from exposure to chemicals, especially hydroquinone and/or glutaraldehyde. The report also emphasises the crucial role of inspection of facilities and enforcement of compliance with regulations in order to prevent similar incidents

A Systematic Review of Randomized Controlled Interventions for Parents' Distress in Pediatric Leukemia

Objective. This review aims to summarize the existing evidence concerning interventions towards reducing stress in parents with a child with leukemia and their effect in child and family wellbeing. Methods. A systematic review strategy was conducted using MEDLINE covering the period January 1980 to June 2010. Results. Seven randomized controlled trials met the inclusion criteria including in total 1045 parents participants. A variety of cognitive-behavioral interventions problem-solving skills training programs have been used for managing distress in parents and children. Outcome measures are assessed by self-report, observer report, behavioral/psychological, and physiological measures. The most prominent methodological problems were the marked heterogeneity in stress measurement and the relative absence of proper measurement and adjustment of moderating and mediating factors. The largest effect has been obtained by combined cognitive-behavioral interventions with promising but limited evidence for several other psychological interventions. Conclusions. Recommendations for future RCTs are provided, and particular attention to the quality of trial design and reporting is highlighted

Swiping more, committing less: Unraveling the links among dating app use, dating app success, and intention to commit infidelity

The present study was conducted to explore the cognitive processes linking people's perceptions of their mobile dating app experience and their intention to commit infidelity. Three hundred and ninety-five participants were recruited through a U.S. based university (44.6%) and MTurk (55.4%). Our results indicate that people's perceived success on a dating app was positively associated with their intention to commit infidelity through self-perceived desirability, and negatively associated with their intention to commit infidelity through perceived amount of available partners. These findings are discussed in light of theories of relational investment

Possible scenarios for soft and semi-hard components structure in central hadron-hadron collisions in the TeV region

Possible scenarios in hh collisions in the TeV regions are discussed in full phase space. It is shown that at such high energies one should expect strong KNO scaling violation and a ln(s) increase of the average charged multiplicity of the semi-hard component, resulting in a huge mini-jet production.Comment: 20 pages, 9 PS figures included, LaTeX2e with AMSmath, epsfi

Polynomial Growth Harmonic Functions on Finitely Generated Abelian Groups

In the present paper, we develop geometric analytic techniques on Cayley graphs of finitely generated abelian groups to study the polynomial growth harmonic functions. We develop a geometric analytic proof of the classical Heilbronn theorem and the recent Nayar theorem on polynomial growth harmonic functions on lattices \mathds{Z}^n that does not use a representation formula for harmonic functions. We also calculate the precise dimension of the space of polynomial growth harmonic functions on finitely generated abelian groups. While the Cayley graph not only depends on the abelian group, but also on the choice of a generating set, we find that this dimension depends only on the group itself.Comment: 15 pages, to appear in Ann. Global Anal. Geo