Effect of Freestream Turbulence on Roughness-induced Crossflow Instability

AbstractThe effect of freestream turbulence on generation of crossflow disturbances over swept wings is investigated through direct nu- merical simulations. The set up follows the experiments performed by Downs et al. (2012). In these experiments the authors use ASU(67)-0315 wing geometry which promotes growth of crossflow disturbances. Distributed roughness elements are locally placed near the leading edge with a given spanwise wavenumber to excite the corresponding stationary crossflow vortices. In present study, we partially reproduce the isotropic homogenous freestream turbulence through direct numerical simulations using freestream spectrum data from the experiments. The generated freestream fields are then applied as the inflow boundary condition for direct numerical simulation of the wing. The distributed roughness elements are modelled through wing surface deformation and placed near the leading edge to trigger the stationary crossflow disturbances. The effects of the generated freestream turbulence on the initial amplitudes and growth of the boundary layer perturbations are then studied

Ektopik Gebelik Olgularında Methotrexatın Tedavi Etkinliğinin Değerlendirilmesi

Aim: Our aim in this study was to assess efficacy of singledose methotrexate (MTX) as medical treatment for ectopic pregnancy (EP) by evaluating the results of patients given this treatment. Materials and Methods: Between September 2016 and August 2017, the treatment outcomes of EP cases treated with MTX at Gazi Yaşargil Training and Research Hospital of Health Sciences University were evaluated retrospectively. Results: In total, 126 cases treated for EP were evaluated and 65 cases were included in the study. In cases administered a single dose of MTX, the success rate was 80%, the failure rate was 13.8%, and the emergency surgery rate was 6.2%. The overall success rate of the medical treatment was 90.7% for a second dose of MTX. An unsuccessful result was considered as less than a 15% reduction in the beta-human chorionic gonadotropin (?-hCG) level between 4 and 7 days after single dose MTX administration. In all cases, the rate of emergency surgery after treatment was 9.3%. Conclusions: In our study, success rates in patients with EP treated with MTX were 80% after a single dose and as high as 90.7% when a second dose was addedAmaç: Bu çalışmadaki amacımız ektopik gebelik’ te (EP) medikal tedavi olarak tek doz methotrexat (MTX) tedavisi verilen olguların sonuçlarının değerlendirilmesidir. Materyal ve Metot: Eylül 2016 ile Ağustos 2017 arasında Sağlık Bilimleri Üniversitesi Gazi Yaşargil Eğitim ve Araştırma Hastanesinde tedavi edilen EP olgularında MTX tedavisi uygulanmış olanların tedavi sonuçları retrospektif olarak değerlendirildi. Bulgular: Çalışmanın yapıldığı tarihler arasında EP nedeniyle tedavi edilen 126 olgu çalışmaya dahil edildi. Tek doz MTX tedavisi başlanan olgularda başarı oranı %80, başarısızlık %13.8 ve acil cerrahi oranı %6.2 olarak gerçekleşti. Tek doz MTX uygulaması sonrasında 4 ve 7 günler arsında betahuman chorionic gonadotropin (?-hCG) seviyesinin %15 ten az düşmesi sonucunda başarısız olarak kabul edilen olgularda yapılan 2. doz MTX sonucunda, medikal tedavinin toplam başarı oranı %90.7 olarak gerçekleşirken, bu olguların tümünde tedavi sonrası acil cerrahi oranı %9.3 olarak gerçekleşti. Sonuç: Çalışmamızda uygun endikasyonla MTX tedavisi uygulanan EP olgularında medikal tedavinin başarı oranı %90.7 gibi oldukça yüksek bir oranda gerçekleşmiş olup olguların sadece %9.3 de MTX tedavisi sonrasında acil cerrahi tedavi gerekmiştir

Unlocking community capability through promotion of self-help for health: experience from Chakaria, Bangladesh

Background People’s participation in health, enshrined in the 1978 Alma Ata declaration, seeks to tap into community capability for better health and empowerment. One mechanism to promote participation in health is through participatory action research (PAR) methods. Beginning in 1994, the Bangladeshi research organization ICDDR,B implemented a project “self-help for health,” to work with existing rural self-help organizations (SHOs). SHOs are organizations formed by villagers for their well-being through their own initiatives without external material help. This paper describes the project’s implementation, impact, and reflective learnings. Methods Following a self-help conceptual framework and PAR, the project focused on building the capacity of SHOs and their members through training on organizational issues, imparting health literacy, and supporting participatory planning and monitoring. Quarterly activity reports and process documentation were the main sources of qualitative data used for this paper, enabling documentation of changes in organizational issues, as well as the number and nature of initiatives taken by the SHOs in the intervention area. Health and demographic surveillance system (HDSS) data from intervention and comparison areas since 1999 allowed assessment of changes in health indicators over time. Results Villagers and members of the SHOs actively participated in the self-help activities. SHO functionality increased in the intervention area, in terms of improved organizational processes and planned health activities. These included most notably in convening more regular meetings, identifying community needs, developing and implementing action plans, and monitoring progress and impact. Between 1999 and 2015, while decreases in infant mortality and increases in utilization of at least one antenatal care visit occurred similarly in intervention and comparison areas, increases in immunization, skilled birth attendance, facility deliveries and sanitary latrines were substantially more in intervention than comparison areas. Conclusion Building community capability by working with pre-existing SHOs, encouraging them to place health on their agendas, strengthening their functioning and implementation of health activities led to sustained improvements in utilization of services for over 20 years. Key elements underpinning success include efforts to build and maintain trust, ensuring social inclusion in project activities, and balancing demands for material resources with flexibility to be responsive to community needs

High concentration of childhood deaths in the low-lying areas of Chakaria HDSS, Bangladesh: findings from a spatial analysis

Background: Despite significant reduction of childhood mortality in Bangladesh, large spatial variations persist. Identification of lower level spatial units with higher concentrations of deaths can be useful for strengthening services in these areas. This paper reports findings from a spatial analysis of deaths in Chakaria, a rural subdistrict, where a Health and Demographic Surveillance System has been in place since 1999. Chakaria is an INDEPTH member site. Methods: An analysis was done of 339 deaths among nearly 24,500 children under the age of five during 2005–2008. One ward, the lowest level of administrative units, was the unit of spatial analysis. Data from 24 wards were analyzed. The Discrete Poisson Probability Model was used to identify the clustering of deaths. Results: Deaths were concentrated within 12 wards located in the low-lying deltaic flood plains of the Chakaria HDSS area. The risk of death in the low-lying areas was statistically, significantly higher, 1.5 times, than the non-low-lying areas (p<0.02). Conclusion: Spatial analysis can be a useful tool for identifying high-risk mortality areas. An understanding of the risk factors prevalent in the low-lying areas can help design effective interventions to reduce mortality in these areas

Controlling the mode of operation of organic transistors through side-chain engineering

Electrolyte-gated organic transistors offer low bias operation facilitated by direct contact of the transistor channel with an electrolyte. Their operation mode is generally defined by the dimensionality of charge transport, where a field-effect transistor allows for electrostatic charge accumulation at the electrolyte/semiconductor interface, whereas an organic electrochemical transistor (OECT) facilitates penetration of ions into the bulk of the channel, considered a slow process, leading to volumetric doping and electronic transport. Conducting polymer OECTs allow for fast switching and high currents through incorporation of excess, hygroscopic ionic phases, but operate in depletion mode. Here, we show that the use of glycolated side chains on a thiophene backbone can result in accumulation mode OECTs with high currents, transconductance, and sharp subthreshold switching, while maintaining fast switching speeds. Compared with alkylated analogs of the same backbone, the triethylene glycol side chains shift the mode of operation of aqueous electrolyte-gated transistors from interfacial to bulk doping/transport and show complete and reversible electrochromism and high volumetric capacitance at low operating biases. We propose that the glycol side chains facilitate hydration and ion penetration, without compromising electronic mobility, and suggest that this synthetic approach can be used to guide the design of organic mixed conductors

Factors Controlling Properties of Ca-Mg, Ca-Er, Ca-Nd, or Ca-Y-Modified Aluminosilicate Glasses Containing Nitrogen and Fluorine

Glasses with composition (in eq.%) (30 − x)Ca:xM:55Si:15Al:80O:15N:5F have been prepared with different levels of substitution of Ca2+ cations by Mg2+, Y3+, Er3+, or Nd3+. The properties of these glasses are examined in detail and changes observed in molar volume (MV), free volume, fractional glass compactness, Young's modulus, microhardness, glass transition temperature, and thermal expansion as a function of M content are presented. Using linear regression analysis, evidence is presented which clearly shows that these glass properties are either solely dependent on the effective cation field strength, if modifier cation valency is the same (e.g., Mg substitution for Ca), or dependent on the effective cation field strength and the number of (Si, Al) (O, N, F) tetrahedra associated with each modifier when Ca is replaced by the trivalent modifiers. Combining these correlations with those observed previously relating glass properties to N and F substitution for O, it becomes apparent that glass properties for Ca–M–Si–Al–O–N–F glasses can be described by correlations which involve independent, but additive contributions by N and F substitution levels, effective cation field strength, and the number of tetrahedra associated with each modifier ion

Properties of Ca–(Y)–Si–Al–O–N–F Glasses: Independent and Additive Effects of Fluorine and Nitrogen

Thirty glasses of composition (in equivalent percent) 20-xCa:xY:50Si:30Al:(100-y-z)O:yN:zF, with x = 0, 10; y = 0, 10, 20, and z = 0, 1, 3, 5, 7 were prepared by melting and casting. All glasses were X-ray amorphous. Glass molar volumes (MV) decreased with nitrogen substitution for oxygen for all fluorine contents and, correspondingly, glass fractional compactness increased. Fluorine substitution of oxygen had virtually no effect on molar volume or fractional glass compactness for the three nitrogen contents tested. Young's modulus and microhardness were virtually unaffected by fluorine substitution for oxygen while nitrogen substitution for oxygen caused increases in these two properties. Glass-transition temperature and dilatometric-softening point values all decreased with increasing fluorine substitution levels, while increasing nitrogen substitution caused values for these thermal properties to increase. Correspondingly, the thermal expansion coefficient increased with fluorine and decreased with nitrogen substitution levels. Using property value differences between glasses containing fluorine and the corresponding glass containing 0 eq.% F enabled 24 data points to be used to determine the effect of fluorine on Tg,dil and TDS. The trends were linear with a gradient for both properties of the order of −22°C (eq.% F)−1. For the nitrogen effect, 20 data points were analyzed for trend effects. As expected from earlier work, all trends had good linearity. Gradients were for Tg,dil and TDS +2.5°C (eq.% N)−1, which are fairly similar to previous results in oxynitride systems. All of the data collected and its analysis clearly shows that the substitution effects of fluorine for oxygen and nitrogen for oxygen are independent and additive with the fluorine substitution. The property trends of the glasses are discussed in terms of their implications for glass structure.The authors wish to acknowledge Science Foundation Ireland and Valencian Small and Medium Enterprise Institute for financial support of this research and to thank colleagues in Materials Ireland and the Materials and Surface Science Institute for their help and advice

N-type organic electrochemical transistors with stability in water.

Organic electrochemical transistors (OECTs) are receiving significant attention due to their ability to efficiently transduce biological signals. A major limitation of this technology is that only p-type materials have been reported, which precludes the development of complementary circuits, and limits sensor technologies. Here, we report the first ever n-type OECT, with relatively balanced ambipolar charge transport characteristics based on a polymer that supports both hole and electron transport along its backbone when doped through an aqueous electrolyte and in the presence of oxygen. This new semiconducting polymer is designed specifically to facilitate ion transport and promote electrochemical doping. Stability measurements in water show no degradation when tested for 2 h under continuous cycling. This demonstration opens the possibility to develop complementary circuits based on OECTs and to improve the sophistication of bioelectronic devices