Direct imaging of changes in aerosol particle viscosity upon hydration and chemical aging

Organic aerosol particles (OA) play major roles in atmospheric chemistry, climate, and public health. Aerosol particle viscosity is highly important since it can determine the ability of chemical species such as oxidants, organics or water to diffuse into the particle bulk. Recent measurements indicate that OA may be present in highly viscous states, however, diffusion rates of small molecules such as water are not limited by these high viscosities. Direct observational evidence of kinetic barriers caused by high viscosity and low diffusivity in aerosol particles were not available until recently; and techniques that are able to dynamically quantify and track viscosity changes during atmospherically relevant processes are still unavailable for atmospheric aerosols. Here we report quantitative, real-time, online observations of microscopic viscosity changes in aerosol particles of atmospherically relevant composition, using fluorescence lifetime imaging (FLIM) of viscosity. We show that microviscosity in ozonated oleic acid droplets and secondary organic aerosol (SOA) particles formed by ozonolysis of myrcene increases substantially with decreasing humidity and atmospheric oxidative aging processes. Furthermore, we found unexpected heterogeneities of microviscosity inside individual aerosol particles. The results of this study enhance our understanding of organic aerosol processes on microscopic scales and may have important implications for the modeling of atmospheric aerosol growth, composition and interactions with trace gases and clouds.Engineering and Physical Sciences Research Council (Career Acceleration Fellowship (Grant ID: EP/I003983/1), Prize studentship), Natural Environment Research Council (Studentship NE/J500070/1), European Research Council (Grant ID: 279405), Max Planck Society, European Union project PEGASOS (Grant ID: 265148

Pilot study to define criteria for Pituitary Tumors Centers of Excellence (PTCOE):results of an audit of leading international centers

Purpose: The Pituitary Society established the concept and mostly qualitative parameters for defining uniform criteria for Pituitary Tumor Centers of Excellence (PTCOEs) based on expert consensus. Aim of the study was to validate those previously proposed criteria through collection and evaluation of self-reported activity of several internationally-recognized tertiary pituitary centers, thereby transforming the qualitative 2017 definition into a validated quantitative one, which could serve as the basis for future objective PTCOE accreditation. Methods: An ad hoc prepared database was distributed to nine Pituitary Centers chosen by the Project Scientific Committee and comprising Centers of worldwide repute, which agreed to provide activity information derived from registries related to the years 2018–2020 and completing the database within 60 days. The database, provided by each center and composed of Excel® spreadsheets with requested specific information on leading and supporting teams, was reviewed by two blinded referees and all 9 candidate centers satisfied the overall PTCOE definition, according to referees’ evaluations. To obtain objective numerical criteria, median values for each activity/parameter were considered as the preferred PTCOE definition target, whereas the low limit of the range was selected as the acceptable target for each respective parameter. Results: Three dedicated pituitary neurosurgeons are preferred, whereas one dedicated surgeon is acceptable. Moreover, 100 surgical procedures per center per year are preferred, while the results indicated that 50 surgeries per year are acceptable. Acute post-surgery complications, including mortality and readmission rates, should preferably be negligible or nonexistent, but acceptable criterion is a rate lower than 10% of patients with complications requiring readmission within 30 days after surgery. Four endocrinologists devoted to pituitary diseases are requested in a PTCOE and the total population of patients followed in a PTCOE should not be less than 850. It appears acceptable that at least one dedicated/expert in pituitary diseases is present in neuroradiology, pathology, and ophthalmology groups, whereas at least two expert radiation oncologists are needed. Conclusion: This is, to our knowledge, the first study to survey and evaluate the activity of a relevant number of high-volume centers in the pituitary field. This effort, internally validated by ad hoc reviewers, allowed for transformation of previously formulated theoretical criteria for the definition of a PTCOE to precise numerical definitions based on real-life evidence. The application of a derived synopsis of criteria could be used by independent bodies for accreditation of pituitary centers as PTCOEs.</p

Response of Acroptilon repens to simulated herbivory and soil disturbance

Acroptilon repens is an invasive weed in North America but also causes problems in disturbed habitats in its native range in Asia. In order to test the effect of simulated biological control and soil disturbance on established A. repens patches and the competing vegetation, two levels of shoot clipping as well as soil tillage were imposed on A. repens patches in an undisturbed meadow and at two fallowland sites in the native range of the weed. At the meadow site, 2 years of partial clipping of shoots and of soil tillage had no influence on A. repens performance, while soil tillage significantly reduced the above-ground biomass of the competing vegetation. At the fallowland sites, which had been continuously cultivated for several years prior to the experiment, A. repens shoot density, biomass and number of seed heads were significantly higher in the undisturbed control than in the tillage plots. The total number of seed heads per unit area increased with shoot density up to 200 shoots m-2. These results indicate that A. repens has considerable regrowth capacities that allow established patches to tolerate substantial losses of above-ground biomass and that the competitive ability of A. repens is favoured both when soil disturbance is imposed on previously undisturbed sites, as well as when repeated soil disturbance is abandoned. The only promising nonchemical herbicide-based approach to reduce the competitive ability and seed output of A. repens appears to be a long-term management that enhances the interspecific plant competition by reducing soil disturbance and selectively damaging A. repens. © 2005 Association of Applied Biologists

Density and dynamics of Acroptilon Repens L., patches in Turkey

Acroptilon repens is an herbaceous perennial that propagates by seeds and vegetative means. Its natural range extends from Turkey throughout Central Asia to China. A. repens is a major weed for grape, orchards and meadow area in Central of Turkey. Our objective was to determine density and expanding of A. repens patches in Central of Turkey. The patche experiments were conducted for an 6 undisturbed meadow in 2002-2003. Six of 1×1=1 m2 plots were randomly selected in each patch (2 central (C), 2 middle (M) and 2 edge (E). Shoot density and height of A. repens were recorded at two different times (May and August) and also, fresh-dry weight and patch growth were recorded in August for each of the years from each plots The results of the 6 patches experiments for shoot height of A. repens in 2002 and 2003 ranged from 24.94 -31.33 cm and 19.31-25.41 cm plot-1, respectively. In addition to this, the shoot density of A. repens in 2002 and 2003 ranged from 5.83-26.83 shoot plot-1 and 7.50-24.83 shoot plot-1, respectively. The shoot density of A. repens was higher in central plot than the edge plot in 2002-2003. The patches of A. repens in Goreme1, Urgup 1, Urgup 3 and Urgup 4 in 2002-2003 were extended totaly 5, 16, 9 and 12 shoot plot-1, respectively

Population density and reproductive output of Acroptilon Repens L., in Turkey

Acroptilon repens of the family Asteraceae L., is a rhizomatous perennial, extends from Turkey throughout Central Asia to China. A. repens is a major weed in vineyards, orchards and meadows in Central Turkey. Our aim was to describe the population density of A. repens patches in Central of Turkey. The patch experiment was conducted in 15 undisturbed meadows in 2003. Six 1 m2 plots were placed in each patch, 2 in the centre (C), 2 halfway between the centre and the edge (M), and 2 at the edge of each patch (E). Twenty capitula were randomly selected from each plot to record the number of healthy and undeveloped seeds as well as the number of seeds damaged by herbivores. Population density of A. repens was recorded in August when the plant was mature. Mean shoot density of the 15 A. repens patches in 2003 was 12.14 m-2. The capitula density per shoot ranged 4.20- 229.60 plant-1. The relationship between mean number of capitula per shoot and shoot density in A. repens were found negative correlation. The number of seeds per capitula of A. repens was on average 52.36 and ranged from 12.06-24.31

Effect of Friction Welding Parameter on Mechanical and Microstructural Properties of Dissimilar AISI 1010-ASTM B22 Joints

WOS: 000290083700022Rotary friction welding is one of the most economical and efficient production methods for joining similar and dissimilar materials. It is widely used with metals and thermoplastics in a wide variety of aviation, transport, and aerospace industrial component designs. Individually, mild steel to mild steel and copper to copper are normally easy to weld by fusion welding methods, but the joint of mild steel to copper can be extremely difficult due to the differences in the two materials' melting temperature, density, strength, and thermal conductivity. Thus, these kinds of problems can be eliminated by a solid-state friction welding technique. Hence, the current study attempts to understand the friction welding characteristics of mild steel-bronze dissimilar parts. This study looks into the influence of process parameters, which includes friction pressure, upsetting pressure, and upset time on the axial shortening, hardness, microstructure, and tensile properties of the welds. The optimum parameters for upset time, upset pressure, and friction pressure necessary for welding were obtained. Finally, the obtained mechanical properties results were commented on the light of optical microscopy.Turkish Track FactoryThe authors wish to thank Prof. Dr. G. Said and H. Ozden for their valuable contributions. Also, special thanks to Turkish Track Factory for its support and guidance during the experimental stage

#Demonetization and Its Impact on the Indian Economy – Insights from Social Media Analytics

Part 4: Social Media and Web 3.0 for SmartnessInternational audienceIn recent times, twitter has emerged as a central site where people express their views and opinions on happenings surrounding their lives. This paper tries to study the general public sentiment surrounding a major breakthrough event for the Indian economy i.e. demonetization by capturing 1,44,497 tweets about demonetization. The paper also tries to find the impact of demonetization on various sectors of the economy and whether there exists any correlation between the public sentiments expressed over twitter and the stock market performance of Nifty 50 companies. The industries were classified into cash dependent and independent sectors and the impact on both were separately studied. It was found there exists no significant correlation between the sentiments expressed over twitter about demonetization and the performance of various sectors in the economy and twitter sentiments alone do not necessarily predict the performance of financial market

Direct imaging of changes in aerosol particle viscosity upon hydration and chemical aging

Organic aerosol particles (OA) play major roles in atmospheric chemistry, climate, and public health. Aerosol particle viscosity is highly important since it can determine the ability of chemical species such as oxidants, organics or water to diffuse into the particle bulk. Recent measurements indicate that OA may be present in highly viscous states, however, diffusion rates of small molecules such as water are not limited by these high viscosities. Direct observational evidence of kinetic barriers caused by high viscosity and low diffusivity in aerosol particles were not available until recently; and techniques that are able to dynamically quantify and track viscosity changes during atmospherically relevant processes are still unavailable for atmospheric aerosols. Here we report quantitative, real-time, online observations of microscopic viscosity changes in aerosol particles of atmospherically relevant composition, using fluorescence lifetime imaging (FLIM) of viscosity. We show that microviscosity in ozonated oleic acid droplets and secondary organic aerosol (SOA) particles formed by ozonolysis of myrcene increases substantially with decreasing humidity and atmospheric oxidative aging processes. Furthermore, we found unexpected heterogeneities of microviscosity inside individual aerosol particles. The results of this study enhance our understanding of organic aerosol processes on microscopic scales and may have important implications for the modeling of atmospheric aerosol growth, composition and interactions with trace gases and clouds.Engineering and Physical Sciences Research Council (Career Acceleration Fellowship (Grant ID: EP/I003983/1), Prize studentship), Natural Environment Research Council (Studentship NE/J500070/1), European Research Council (Grant ID: 279405), Max Planck Society, European Union project PEGASOS (Grant ID: 265148