Free energy of colloidal particles at the surface of sessile drops

The influence of finite system size on the free energy of a spherical particle floating at the surface of a sessile droplet is studied both analytically and numerically. In the special case that the contact angle at the substrate equals $\pi/2$ a capillary analogue of the method of images is applied in order to calculate small deformations of the droplet shape if an external force is applied to the particle. The type of boundary conditions for the droplet shape at the substrate determines the sign of the capillary monopole associated with the image particle. Therefore, the free energy of the particle, which is proportional to the interaction energy of the original particle with its image, can be of either sign, too. The analytic solutions, given by the Green's function of the capillary equation, are constructed such that the condition of the forces acting on the droplet being balanced and of the volume constraint are fulfilled. Besides the known phenomena of attraction of a particle to a free contact line and repulsion from a pinned one, we observe a local free energy minimum for the particle being located at the drop apex or at an intermediate angle, respectively. This peculiarity can be traced back to a non-monotonic behavior of the Green's function, which reflects the interplay between the deformations of the droplet shape and the volume constraint.Comment: 24 pages, 19 figure

Global Retinoblastoma Presentation and Analysis by National Income Level

Importance: Early diagnosis of retinoblastoma, the most common intraocular cancer, can save both a child's life and vision. However, anecdotal evidence suggests that many children across the world are diagnosed late. To our knowledge, the clinical presentation of retinoblastoma has never been assessed on a global scale. Objectives: To report the retinoblastoma stage at diagnosis in patients across the world during a single year, to investigate associations between clinical variables and national income level, and to investigate risk factors for advanced disease at diagnosis. Design, Setting, and Participants: A total of 278 retinoblastoma treatment centers were recruited from June 2017 through December 2018 to participate in a cross-sectional analysis of treatment-naive patients with retinoblastoma who were diagnosed in 2017. Main Outcomes and Measures: Age at presentation, proportion of familial history of retinoblastoma, and tumor stage and metastasis. Results: The cohort included 4351 new patients from 153 countries; the median age at diagnosis was 30.5 (interquartile range, 18.3-45.9) months, and 1976 patients (45.4) were female. Most patients (n = 3685 84.7%) were from low-and middle-income countries (LMICs). Globally, the most common indication for referral was leukocoria (n = 2638 62.8%), followed by strabismus (n = 429 10.2%) and proptosis (n = 309 7.4%). Patients from high-income countries (HICs) were diagnosed at a median age of 14.1 months, with 656 of 666 (98.5%) patients having intraocular retinoblastoma and 2 (0.3%) having metastasis. Patients from low-income countries were diagnosed at a median age of 30.5 months, with 256 of 521 (49.1%) having extraocular retinoblastoma and 94 of 498 (18.9%) having metastasis. Lower national income level was associated with older presentation age, higher proportion of locally advanced disease and distant metastasis, and smaller proportion of familial history of retinoblastoma. Advanced disease at diagnosis was more common in LMICs even after adjusting for age (odds ratio for low-income countries vs upper-middle-income countries and HICs, 17.92 95% CI, 12.94-24.80, and for lower-middle-income countries vs upper-middle-income countries and HICs, 5.74 95% CI, 4.30-7.68). Conclusions and Relevance: This study is estimated to have included more than half of all new retinoblastoma cases worldwide in 2017. Children from LMICs, where the main global retinoblastoma burden lies, presented at an older age with more advanced disease and demonstrated a smaller proportion of familial history of retinoblastoma, likely because many do not reach a childbearing age. Given that retinoblastoma is curable, these data are concerning and mandate intervention at national and international levels. Further studies are needed to investigate factors, other than age at presentation, that may be associated with advanced disease in LMICs. © 2020 American Medical Association. All rights reserved

Comparison of diurnal variation of airborne pollen in Mar del Plata (Argentina): 2. Arboreal pollen

Intradiurnal variation of arboreal pollen (AP) in Mar del Plata city is compared during three non -consecutive years of survey and described in relation to the associated weather. The daily pattern of pollen abundance has a maximum between 10:00 and 12:00 h, while a minimum occurs at 18:00 h. The first two years of survey showed homogeneous daily trends, but in 1995 the maximum and minimum concentrations were delayed because of the change in position of the collecting station. Arboreal pollen spectrum presented qualitative and quantitative changes in the three years analysed. Results indicate optimal conditions for diurnal dispersion of arboreal pollen are high temperatures and low relative humidity. Also interaction between source position and wind direction has important effects on the timing of the peaks of some pollen types.Fil:Gardiol, J.M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Matriz porosa do BV60S no tratamento de defeitos ósseos críticosem rádios de cães

O objetivo deste estudo foi avaliar o efeito da matriz porosa do biovidro de composição molar 60% SiO2 - 36% CaO - 4% P2O5 (BV60S) no tratamento de defeitos ósseos críticos de cães. Foram utilizados 20 cães, machos, sem raça definida, com dois anos e massa corporal média de 25kg. Foram constituídos três grupos experimentais: defeitos ósseos preenchidos com BV60S (BV), com osso autógeno (C+) e defeitos não preenchidos (C-). A regeneração óssea foi avaliada por meio de exames radiográficos, densitométricos e histomorfométricos ao longo de 90 dias. A matriz do BV60S mostrou rápida reabsorção com redução média de 12,62% a cada 15 dias. A regeneração foi completa no grupo C+ e incompleta nos grupos BV e C-, aos 90 dias. A área de neoformação óssea foi semelhante entre os grupos BV e C-, em todos os tempos estudados. Conclui-se que a matriz porosa do BV60S possui rápida reabsorção, não sendo eficiente no tratamento de defeitos ósseos críticos em rádios de cães

Good Practice for Introducing Radiopharmaceuticals for Clinical Use

BACKGROUNDRadiopharmaceuticals are radiolabelled compounds designed to deliver diagnostic information as a result of their incorporation with selected cellular targets. These exquisite molecular tools are essential components of nuclear medicine technology and must be prepared prior to administration to the patient. The production of radiopharmaceuticals must be performed by al icensed commercial organization，or altematively using in-house good manufacturing practice (GMP) compliant facilities. According to the mostwidely accepted defmition，a radiopharmaceutical is classified as a‘ medicinal product\u27 and，therefore，its production，characterization and quality control testing should comply with the rules for manufacturing/compounding sterile products intended for human injection. These rules have evolved over the years to ensure that a safe and high quality product is adrninistered to the patient at all times. In countries that are experienced in this technology，the most common route ofsupplying radiopharmaceuticals is through a network of commercial production sites. In this context，the commercial producer retains the responsibility of ensuring that the quality and safety of leradiopharmaceutical product complies with intemationally accepted standards. However，i n-house preparations are also permitted when performed in aGMP compliant facility. Positron enlIssion tomography (PET) and single-photon emission computed tomography (SPECT) radionuclide diagnostic imaging，are complextechnologies that require certain infrastructure to be in place before the population of a country can benefit from their application. In many countries where these technologies have been developed and used in clinical practice for some time，the necessary components are already established. These include but are not limited to (a) the manufacture of radiopharmaceutical to a GMP standard，(b) a clear gularatory framework，(c) availability of scanning centres and (d) suitably qualified personnel. Countries with less extensive experience in the mannufacture of radiopharmaceuticals may encounter several challenges，which，in the first instance, include a basic lack of expertise.In addition，there may also be a lack of clarity with respect to the rules and guidance regarding the process of technological development.\n11.2 JAPANThere are two types of radiopharmaceuticals in clinical usage, namely approvedradiopharmaceuticals and compounded radiopharmaceuticals produced by approved synthesis modules. The Ministry of Health, Labour and Welfare (WHL W) and the Pharmaceutical and Medical Device Agency (PMDA) are responsible for the approval of radiopharmaceuticals and medical devices. For these radiopharmaceuticals GMP, GCP and good laboratory practice(GLP) are required in the production and delivery processes, pre-clinical safety testing and clinical trials, respectively. Radiophannaceuticals should be produced using an approved synthesis module and all the process and quality assurance should be done according to the guidelines and monographs published by a scientific organization (Japanese Society of Nuclear Medicine (JSNM). Recently, the JSNM Molecular Imaging Strategic Committee (JSNM-MISC) published"New Guidelines and qualification for research using in-house PET drugs", including a guideline for the standardization and quality assurance of in-house PET drugs; guidelines for standardization and quality control of PET imaging; guidelines for the clinical evaluation of PET drugs and guidelines for pre-clinical safety tests of PET drugs. JSNM-MISC is also working on developing and publishing new radiophannaceuticals monographs. This is to facilitate safe and effective clinical research, as well as approval of synthesis modules for newradiopharmaceuticals. JSNM-MISC and National Institute of Radiological Sciences have started an educational program for PET radiopharmaceuticals production under the JSNMGuidelines that operates site-visit programs for audit, and closely communicates with government authorities to harmonize the guidelines and government regulations