THE EFFECT OF PHYSICIANS’ GENDER AND EXPERIENCE ON PERSIAN MEDICAL INTERACTIONS

This study focusing on physician-patient interactions aimed to find out whetherphysicians’ gender and experience influence Persian doctor-patient interactions. Sopower strategies in physician-patient interactions were extracted and categorized toexplore the relationship between physicians’ gender and experience and power strategies.Fieldwork was conducted in clinics and hospitals of Rafsanjan city in Iran. One hundredphysician-patient consultations were audiotaped and transcribed during 2011-2012.Woods’ (2006) view was used to examine four strategies of power and knowledge ontheir talk. The findings pointed out the importance of investigating discourse of medicinein order to improve medical consultations, especially physician-patient interactions.Our study confirmed some previous assertions that physician-patient interactionswere asymmetrical. Physicians controlled and dominated the medical consultations byquestioning, interruptions, directive statements and tag questions. The analysis of the datarevealed that all power strategies were applied in Iranian physician-patient interactions.The results of Chi-Square tests indicated that there was a significant relationship betweenpower strategies and physicians’ experience and gender. It was concluded that the femaleand inexperienced physicians tended to control consultations by questioning, interruption,directives and tag questions more than the male and experienced physicians

Studie des Einflusses von Nanopartikeln auf die Leistung und die Eigenschaften von Polyamid 6

The number of efforts in order to modify the properties of polymeric fibers by organic or inorganic particles has increased in recent times because of increasing interest of fiber research in hightech fiber applications. In addition to these attempts, the innovation of nanotechnology also leads to the development of nanoparticles for various end uses such as nanocomposite fibers. In this study spherical silica nanoparticles were introduced into polyamide 6 and drawn into filaments through a melt extrusion process. With two different particle diameters, different particle concentrations and types of surface modified silica as variables, preparation of polyamide 6/SiO2 nanocomposites were investigated for three different nanocomposite preparation methods (i) melt intercalation, (ii) solution intercalation and (iii) in-situ polymerization, while pure polyamide 6 was spun under the same condition as a reference. The study was carried out for multifilament nanocomposite fibers consisting of nano-silica fillers embedded in a fiber grade polyamide 6 matrix. Thus the effect of SiO2 nanoparticles on the thermal, structural, morphological and tensile properties of polyamide-silica nanocomposites fibers were investigated by using thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and standard tensile testing methods, respectively. TGA results showed that thermal stability of nanocomposites was notably improved compared to pure polyamide 6. According to DSC and XRD results the introduction of different silica nanoparticles into the polymer matrix as well as the cooling rate in the preparation method caused a phase transformation of the crystals of the polymer matrix from α- to γ-form crystals. SEM observations show that In-situ polymerization and solution intercalation are suitable methods for the preparation of inorganic/organic nanocomposites which can avoid the agglomeration of inorganic particles in polymer matrices, moreover modified silica particle disperse more homogeneously in the PA 6 matrix in comparison with the unmodified silica particle. GPC and relative viscosity measurement indicate that by increasing the silica content the molecular weight of nanocomposites decreased in comparison to pure polyamide 6 which suggests that there is an interaction between silica and polyamide 6. This is supported by a change of the proportion of the amino and carboxylic acid end groups which not only prove a molecular weight reduction but also explains the observed decrease of tenacity of nanocomposite fibers. In contrast to these findings the modulus of PA 6/silica nanocomposite fibers show a tendency to increase with increasing silica content.Eine gerade in jüngster Vergangenheit stark gestiegene Zahl an Untersuchungen zum Thema: Eingenschaftsverbesserungen von Polymerfasern durch Zusatz organischer und anorganischer Partikel, belegt das zunehmende Interesse an high-tech Fasern und deren Anwendungen. Im Rahmen dieser Versuche spielen auch die Innovationen im Bereich der Nanotechnologie eine wichtige Rolle, die zur Entwicklung spezieller Nanopartikel für verschiedene Endanwendungen – wie beispielsweise von Nanokompositfasern – führten. In dieser Studie wurden sphärische Siliziumdioxid-Nanopartikel mit zwei unterschiedlichen Partikeldurchmessern in Polyamid 6 eingearbeitet und daraus über ein Schmelzextrusionsverfahren verstreckte Filamentgarne hergestellt. Weitere, untersuchte Prozessvariable waren dabei der Füllstoffgehalt und die Oberflächenmodifizierung der Siliziumdioxid-Partikel. Die Herstellung von Polyamid 6 / SiO2 Nanokompositen erfolgte nach drei unterschiedlichen Methoden: (a) Schmelzeinterkalation,(b) Lösungsinterkalation und (c) in-situ-Polymerisation. Als Referenz wurde reines Polyamid 6 unter gleichen Bedingungen gesponnen. Die Untersuchung der Nanokomposit fasern bzw. die Wirkung der darin enthaltenen SiO2-Nanopartikel auf dere thermische, strukturelle, morphologische sowie Zugeigenschaften wurde mittels Thermogravimetrie (TGA), Differential Scanning Kalorimetrie (DSC), Röntgenbeugung (XRD), Fourier-Transform-Infrarotspektroskopie (FTIR), Rasterelektronenmikroskopie (REM) und Zugversuchen erfasst. Die TGA Ergebnisse zeigten, dass die thermische Stabilität von Nanokompositen verglichen mit reinen Polyamid 6 besser ist. Aufgrund der DSC und XRD-Ergebnisse führt die Einführung von Siliziumdioxid-Nanopartikeln in die Polymermatrix bei Abkühlung und Kristallisation in der Schmelze zu einer Phasenumwandlung der gebildeten Kristallite von der α-Form in die γ-Form. Die SEMAufnahmen zeigen, dass In-situ-Polymerisation und LösungsiInterkalation geeignete Methoden für die Herstellung von anorganisch-organische Nanokompositen sind, da sie die Agglomeration von anorganischen Partikeln in den Polymermatrices vermeiden, außerdem sind modifizierte Siliziumdioxidpartikel homogener in der PA 6-Matrix dispergiert als im Vergleich dazu unmodifizierte Siliziumdioxidpartikel. GPC Analysen und Messungen der relativen Viskosität weisen darauf hin, dass durch Erhöhung des Siliziumdioxidanteils eine Abnahme des Molekulargewichts der Nanokomposite im Vergleich zu reinem Polyamid 6 erfolgt. Durch die Wirkung des Siliziumdioxids auf das Polyamid 6 wird der Gehalt an Amino-und Carbonsäure-Endgruppen erhöht, dies ist gleichbedeutend mit einer Molekulargewichtsreduktion, woraus seinerseits ein Verlust an Faserfestigkeit bei den Nanokompositfasern resultiert. Die Erhöhung des Siliziumdioxid-Anteils zeigt sich für den Modul im Gegensatz zur Festigkeit ein Trend zu zunehmenden Werten

Rheotaxis-based sperm separation using a biomimicry microfluidic device

Sperm selection is crucial to assisted reproduction, influencing the success rate of the treatment cycle and offspring health. However, in the current clinical sperm selection practices, bypassing almost all the natural selection barriers is a major concern. Here, we present a biomimicry microfluidic method, inspired by the anatomy of the female reproductive tract, that separates motile sperm based on their rheotaxis behavior to swim against the flow into low shear rate regions. The device includes micropocket geometries that recall the oval-shaped microstructures of the female fallopian tube to create shear protected zones for sperm separation. Clinical tests with human samples indicate that the device is capable of isolating viable and highly motile sperm based on their rheotaxis responses, resulting in a separation efficiency of 100%. The device presents an automated alternative for the current sperm selection practices in assisted reproduction