Obtention and Study of Polyurethane-Based Active Packaging with Curcumin and/or Chitosan Additives for Fruits and Vegetables-Part I: Analysis of Morphological, Mechanical, Barrier, and Migration Properties.

Several polyurethane-formulated films with curcumin and/or chitosan additives for food packaging have been previously obtained. The study examines the effect of the additives on the film's morphological, mechanical, barrier, and migration properties. Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), water contact angle, thermogravimetric and differential thermal analysis (TGA and DTGA), differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), oxygen transmission rate (OTR), water vapor transmission rate (WVTR), and the overall and specific migration tests were conducted. The results show that the presence of chitosan significantly increased the overall migration and mechanical properties, such as the elongation at break, tensile strength, and Young's modulus of most polyurethane formulations, while curcumin had a minor influence on the mechanical performance. Based on the results, formulations with curcumin but without chitosan are suitable for food packaging.

Assessing the nationwide impact of COVID-19 mitigation policies on the transmission rate of SARS-CoV-2 in Brazil.

COVID-19 is now identified in almost all countries in the world, with poorer regions being particularly more disadvantaged to efficiently mitigate the impacts of the pandemic. In the absence of efficient therapeutics or large-scale vaccination, control strategies are currently based on non-pharmaceutical interventions, comprising changes in population behavior and governmental interventions, among which the prohibition of mass gatherings, closure of non-essential establishments, quarantine and movement restrictions. In this work we analyzed the effects of 707 governmental interventions published up to May 22, 2020, and population adherence thereof, on the dynamics of COVID-19 cases across all 27 Brazilian states, with emphasis on state capitals and remaining inland cities. A generalized SEIR (Susceptible, Exposed, Infected and Removed) model with a time-varying transmission rate (TR), that considers transmission by asymptomatic individuals, is presented. We analyze the effect of both the extent of enforced measures across Brazilian states and population movement on the changes in the TR and effective reproduction number. The social mobility reduction index, a measure of population movement, together with the stringency index, adapted to incorporate the degree of restrictions imposed by governmental regulations, were used in conjunction to quantify and compare the effects of varying degrees of policy strictness across Brazilian states. Our results show that population adherence to social distance recommendations plays an important role for the effectiveness of interventions and represents a major challenge to the control of COVID-19 in low- and middle-income countries.

Effect of Chitosan and Aloe Vera Extract Concentrations on the Physicochemical Properties of Chitosan Biofilms.

Chitosan films have been extensively studied as dressings in formulations for the treatment of chronic wounds. The incorporation of aloe vera (Aloe barbadensis Miller) into chitosan dressings could potentialize the healing process since aloe vera shows several pharmacological activities. This work aimed to evaluate the effect of aloe vera and chitosan concentrations on the physicochemical properties of the developed films. The films were obtained by casting technique and characterized with respect to their color parameters, morphology, barrier and mechanical properties, and thermal analysis. Results showed that the presence of aloe vera modified the films' color parameters, changed barrier properties, increased fluid handling capacity (FHC), and decreased water-vapor permeability (WVP). The reduced elongation at break resulted in more rigid films. Aloe vera concentration did not significantly change film properties, but the presence of this gel increased the films' stability at temperatures below 200 °C, showing similar behavior as chitosan films above 400 °C. The results suggest a crosslinking/complexation between chitosan and aloe vera, which combine appropriate physicochemical properties for application as wound dressing materials.

Dynamic quarantine: a comparative analysis of the Chilean public health response to COVID-19.

In this study, an analysis of the Chilean public health response to mitigate the spread of COVID-19 is presented. The analysis is based on the daily transmission rate (DTR). The Chilean response has been based on dynamic quarantines, which are established, lifted or prolonged based on the percentage of infected individuals in the fundamental administrative sections, called communes. This analysis is performed at a national level, at the level of the Metropolitan Region (MR) and at the commune level in the MR according to whether the commune did or did not enter quarantine between late March and mid-May of 2020. The analysis shows a certain degree of efficacy in controlling the pandemic using the dynamic quarantine strategy. However, it also shows that apparent control has only been partially achieved to date. With this policy, the control of the DTR partially falls to 4%, where it settles, and the MR is the primary vector of infection at the country level. For this reason, we can conclude that the MR has not managed to control the disease, with variable results within its own territory.

The temperature and regional climate effects on communitarian COVID-19 contagion in Mexico throughout phase 1.

Due to the close relationship between the incidence of infectious diseases by epidemics and environmental conditions, this research explores the temperature, evaporation, precipitation and regional climate effects on the local transmission of coronavirus SARS-CoV-2 inside 31 states and capital of Mexico since February 29 (national onset) to March 31, 2020. Statistical analysis was conducted to explore the association between the daily local COVID-19 confirmed positive cases (LCPC) and both climate characteristics and the daily weather reported by the regional meteorological stations. In this work, the local transmission ratio (LTR) was calculated with the regional LCPC divided by the number of the effective contagion days since regional onset in each state. The results showed a negative association between temperature (mean, max and min) and climate classification with both LCPC and LTR variables. The precipitation associated positively with LCPC and LTR. The associations between the climate classification with LCPC and LTR are statistically significant. The tropical climate (mean temperature around 25.95 °C and mean precipitation around 8.74 mm) delayed the regional onset. However, the regional onset in dry climates emerged earlier as consequence of the lower temperatures and higher precipitations (20.57 °C and 20.87 mm respectively) than the observed in the tropical climate. The fastest regional onsets were observed in tempered climates in states where the lowest temperatures and lowest precipitations were registered (19.65 °C and 8.48 mm respectively). Meteorological factors influenced the trend on the regional outbreaks in Mexican's states likely by the host predisposition and susceptibility during the cold winter season. In Mexico, the climate characteristics played a crucial role on the local infection during the phase 1 being the tempered regions (as Michoacán, Jalisco, Puebla, etc.) more vulnerable than the dry (as Chihuahua, Durango or Zacatecas, etc.) or tropical areas (as Colima, Campeche, Morelos etc.).

Transmission of Microdochium albescens from seeds to seedlings in the pre-germinated cultivation system of irrigated rice / Transmissão de Microdochium albescens de sementes para plântulas de arroz irrigado no sistema de cultivo pré-germinado

The fungus Microdochium albescens is one of the main pathogens associated with irrigated rice seeds in southern Brazil. The objective of the present study was to quantify the transmission of M. albescens from naturally infected seeds to the crown, coleoptile, and first true leaf of the seedlings of six cultivars growing in pre-germinated cultivation system of irrigated rice. Seeding was carried out on a water-saturated substrate, using four untreated seed lots for each of the six cultivars. At 14 days after sowing, the crown, coleoptile, and first true leaf of the seedlings were carefully highlighted, and the samples were disinfected and plated onto potato-sucrose-agar culture medium. M. albescens was transmitted asymptomatically to crown, coleoptile, and first true leaf, at rates of 39.3%, 25.8%, and 5.4%, respectively (these values represent the average incidence of the six cultivars). This is the first report that proves that M. albescens is transmitted from infected seeds to irrigated rice seedlings in a pre-germinated seed system.(AU)

O fungo Microdochium albescens é um dos principais patógenos associados às sementes de arroz irrigado no sul do Brasil. O objetivo do presente estudo foi quantificar a transmissão de M. albescens de sementes naturalmente infectadas para a coroa, coleóptilo e primeira folha verdadeira das plântulas de seis cultivares semeadas em sistema de cultivo pré-germinado de arroz irrigado. A semeadura foi realizada em substrato saturado com água, utilizando quatro lotes de sementes não tratadas para cada uma das seis cultivares. Aos 14 dias após a semeadura, a coroa, o coleóptilo e a primeira folha verdadeira das plântulas foram cuidadosamente dissecados, desinfestados e plaqueados em meio de cultura batata-sacarose-ágar. M. abescens foi transmitido de forma assintomática para coroa, coleóptilo e primeira folha verdadeira, nas taxas de 39,3%, 25,8% e 5,4%, respectivamente (estes valores representam a incidência média das seis cultivares). Este é o primeiro relato de M. albescens transmitido de sementes infectadas para plântulas de arroz irrigado em sistema de semente pré-germinada.(AU)

Transmission of Microdochium albescens from seeds to seedlings in the pre-germinated cultivation system of irrigated rice / Transmissão de Microdochium albescens de sementes para plântulas de arroz irrigado no sistema de cultivo pré-germinado

ABSTRACT: The fungus Microdochium albescens is one of the main pathogens associated with irrigated rice seeds in southern Brazil. The objective of the present study was to quantify the transmission of M. albescens from naturally infected seeds to the crown, coleoptile, and first true leaf of the seedlings of six cultivars growing in pre-germinated cultivation system of irrigated rice. Seeding was carried out on a water-saturated substrate, using four untreated seed lots for each of the six cultivars. At 14 days after sowing, the crown, coleoptile, and first true leaf of the seedlings were carefully highlighted, and the samples were disinfected and plated onto potato-sucrose-agar culture medium. M. albescens was transmitted asymptomatically to crown, coleoptile, and first true leaf, at rates of 39.3%, 25.8%, and 5.4%, respectively (these values represent the average incidence of the six cultivars). This is the first report that proves that M. albescens is transmitted from infected seeds to irrigated rice seedlings in a pre-germinated seed system.

RESUMO: O fungo Microdochium albescens é um dos principais patógenos associados às sementes de arroz irrigado no sul do Brasil. O objetivo do presente estudo foi quantificar a transmissão de M. albescens de sementes naturalmente infectadas para a coroa, coleóptilo e primeira folha verdadeira das plântulas de seis cultivares semeadas em sistema de cultivo pré-germinado de arroz irrigado. A semeadura foi realizada em substrato saturado com água, utilizando quatro lotes de sementes não tratadas para cada uma das seis cultivares. Aos 14 dias após a semeadura, a coroa, o coleóptilo e a primeira folha verdadeira das plântulas foram cuidadosamente dissecados, desinfestados e plaqueados em meio de cultura batata-sacarose-ágar. M. abescens foi transmitido de forma assintomática para coroa, coleóptilo e primeira folha verdadeira, nas taxas de 39,3%, 25,8% e 5,4%, respectivamente (estes valores representam a incidência média das seis cultivares). Este é o primeiro relato de M. albescens transmitido de sementes infectadas para plântulas de arroz irrigado em sistema de semente pré-germinada.

Propriedade de barreira à umidade de embalagens plásticas para produtos oftálmicos / Moisture barrier properties of plastic bottles for ophthalmic eye drops

As propriedades de barreira à umidade de embalagens plásticas para produtos oftálmicos de capacidade nominal de 20 mL e terminação 15 mm nos formatos cilíndrico e oval, de diferentes composições (100% Polietileno de Baixa Densidade (PEBD), 100% Polipropileno (PP) e blendas com percentuais 10% e 40% de Polietileno de Alta Densidade (PEAD) em PEBD), foram estudadas neste trabalho. Foi verificada também a influência do batoque gotejador (de maior ou menor orifício de dosagem) e a influência do fechamento na taxa de transmissão de vapor d'água. O trabalho foi conduzido sob duas condições de estocagem a 25 ºC/40% UR e a 40 ºC/75% UR. Verificou-se que o diâmetro do orifício gotejador não interferiu significativamente na perda de peso da embalagem avaliada a 25 ºC/40% UR. Sob a condição de estocagem a 40 ºC/75% UR verificou-se um aumento da taxa de transmissão de vapor d'água das embalagens comparativamente as mesmas embalagens avaliadas a 25 ºC/40% UR. O sistema de fechamento não favoreceu um acréscimo significativo da taxa de transmissão de vapor d'água, o que indica que a permeação ocorreu principalmente através do corpo da embalagem plástica. A propriedade de barreira foi influenciada pela composição da embalagem plástica chegando a uma redução média de 47% na taxa de transmissão de vapor d'água para a embalagem de PEBD com 40% PEAD em relação à embalagem com100% PEBD de formato cilíndrico. Verificou-se ainda que o formato oval, por apresentar uma maior área superficial exposta comparativamente à embalagem de formato cilíndrico, com regiões de menor espessura de parede, pode favorecer um ligeiro aumento da taxa de transmissão de vapor d'água da embalagem...

The moisture barrier properties of plastic ophthalmic product bottles of nominal capacity 20 mL and finish diameter 15 mm, in cylindrical and oval shapes, with various compositions (100% Low Density Polyethylene(LDPE), 100% polypropylene (PP) and blends with10% and 40% High Density Polyethylene (HDPE) in LDPE), were assessed in this study. The effects of the drop hole size (higher or lower dosage diameter) and the screw cap on the Water Vapor Transmission Rate (WVTR) were also assessed. This study was conducted under two conditions of storage, at 25 °C/40% RH and 40 °C/75% RH. It was observed that the drop hole diameter did not influence significantly the weight loss of the container at 25 °C/40% RH, whereas at 40°C/75% RH, the WVTR of the container was higher than that of the same package at 25 °C/40% RH.The screw cap did not significantly affect the WVTR, indicating that the permeation occurred primarily through the plastic body. The barrier property was influenced by the composition of the plastic container; thus, compared to LDPE, there was a mean reduction of 47% in the WVTR of LDPE blended with 40% HDPE, when both bottles were cylindrical. It was found that the oval shape, because of the larger exposed surface area relative to the cylindrical shape, as well as the presence of regions of thinner wall, can favor a slight increase in the WVTR of the bottle...