Low Transmission Rate Research Articles

Wording the trajectory of the three-year COVID-19 epidemic in a general population – Belgium

The trajectory of COVID-19 epidemic waves in the general population of Belgium was analysed by defining quantitative criteria for epidemic waves from March 2020 to early 2023. Peaks and starting/ending times characterised nine waves numerated I to IX based on the daily reported incidence number (symbol INCID) and three “endemic” interval periods between the first four waves. The SIR compartmental model was applied to the first epidemic wave by fitting the daily prevalence pool (symbol I) calculated as the sum of the daily incidence rate and estimated number of subjects still infectious from the previous days. The basic reproductive number R0 was calculated based on the exponential growth rate during the early phase and on medical literature knowledge of the time of generation of SARS-CoV-2 infection. The first COVID-19 wave was well fitted by an open SIR model. According to this approach, dampened recurrent epidemic waves evolving through an endemic state would have been expected. This was not the case with the subsequent epidemic waves being characterised by new variants of concern (VOC). Evidence-based observations: 1) each epidemic wave affected less than a fifth of the general population; 2) the Vth epidemic wave (VOC Omicron) presented the greatest amplitude. The lack of recurrence of the same VOC during successive epidemic waves strongly suggests that a VOC has a limited persistence, disappearing from the population well before the expected proportion of the theoretical susceptible cohort being maximally infected. Fitting the theoretical SIR model, a limited persistence of VOCs in a population could explain that new VOCs replace old ones, even if the new VOC has a lower transmission rate than the preceding one. In conclusion, acquisition of potential defective mutations in VOC during an epidemic wave is a potential factor explaining the absence of resurgence of a same VOC during successive waves. Such an hypothesis is open to discussion and to rebuttal. A modified SIR model with epidemic waves of variable amplitude related not only to R0 and public health measures but also to acquisition of defective fitting in virus within a population should be tested.

Passionfruit severe leaf distortion virus: Expanded host range, response ofPassifloraspp. plants to infection and transmission byBemisia tabaciMEAM1

AbstractPassionfruit severe leaf distortion virus (PSLDV) is a begomovirus transmitted byBemisia tabaciMiddle East‐Asia Minor 1 (MEAM1), associated with severe disease in passion flowers. This study aimed to evaluate the reaction of plants of different species ofPassiflorato infection with PSLDV, expand the known host range of the virus and determine the minimum virus acquisition and inoculation access periods and the time of virus retention byB. tabaciMEAM1. Plants ofPassiflora cincinnata,P. mucronataandP. malacophyllawere not infected with PSLDV through transmission withB. tabaciMEAM1. When healthy plants of these species were fork grafted onto PSLDV‐infected plants ofP. edulis, only plants ofP. malacophyllaremained uninfected and the virus was not detected by PCR, suggesting immunity to this begomovirus. Plants ofDatura stramonium,Nicotiana benthamiana,N. clevelandii,N. tabacum‘Xanthi’,Solanum lycopersicum(tomato cv. Compack) and several varieties ofManihot esculenta(cassava cvs IAC 118‐96, IAC 6‐01, Paranavaí, IAC 576, IAC 90 and IAC 14) were susceptible to infection with PSLDV through transmission withB. tabaciMEAM1. Adults ofB.tabaciMEAM1 acquired PSLDV after 1 h of feeding on PSLDV‐infected plants ofD.stramonium.They transmitted the virus to healthy plants after feeding on these plants for 1 h, although with low transmission rates. The retention time of PSLDV in the vector was 14 days.

Understanding the impact of mobility on Plasmodium spp. carriage in an Amazon cross-border area with low transmission rate.

Despite the large reduction in malaria incidence in the last decade, the last kilometre to elimination is often the hardest, especially in international border areas. This study investigated the impact of mobility on Plasmodium spp. carriage in people living in a cross-border area in Amazonia with a low malaria transmission rate. We implemented a longitudinal ancillary study in the French Guiana town of St. Georges de l'Oyapock, which is located on the border with Brazil. It was based on data from two transversal surveys performed in October 2017 and October 2018. Data were collected on peri-domestic mobility for food-producing activities, and longer-distance mobility in high-risk areas. Participants were screened for Plasmodium spp. carriage using PCR tests, and treated if positive. Vector density around a participant's home was estimated using a previously published model based on remote sensing and meteorological data. The association between Plasmodium spp. carriage and mobility was analysed using a generalized additive mixed model. A total of 1,192 inhabitants, aged between 0 and 92 years old, were included. Median age was 18 years in 2017 (IQR [8;35]). Plasmodium spp. prevalence in the study population was 7% in 2017 (n = 89) and 3% in 2018 (n = 35). Plasmodium spp. carriage was independently associated with i) travel to the adjoining Oiapoque Indigenous Territories in Brazil (OR = 1.76, p = 0.023), ii) the estimated vector density around a participant's home (High versus Low risk OR = 4.11, p<0.001), iii) slash-and-burn farming (OR = 1.96, p = 0.013), and iv) age (p = 0.032). Specific surveillance systems and interventions which take into account different types of mobility are needed in cross-border areas to achieve and maintain malaria elimination (e.g., reactive case detection and treatment in the places visited).

Physicochemical properties and pork preservation effects of lotus seed drill core powder starch-based active packaging films

Lotus seed drill core powder starch (LCPS)-based active packaging films incorporated with cellulose nanocrystals (CNC) and grapefruit essential oil-corn nanostarch Pickering emulsion (ECPE) were characterized, and their pork preservation effects were investigated in this study. In contrast with corn, potato and rice starches, LCPS showed higher amylose content, elliptical and circular shape with more uniform size distribution. Furthermore, LCPS film exhibited lower light transmittance, stronger tensile strength, and smaller elongation at break compared to the other starch films. Then, the LCPS film containing 4 % CNC and 9 % ECPE was fabricated which had stronger mechanical properties, lower water vapor permeability and oxygen transmission rate, and denser network structure. FTIR and XRD analyses also confirmed that CNC and ECPE were successfully implanted into the LCPS matrix without damaging the crystalline structure of LCPS. Herein, the LCPS/CNC/ECPE film exerted potential antibacterial activity against Escherichia coli and Staphylococcus aureus. Besides, packaging with this composite film significantly preserved the pork during cold storage via decreasing its juice loss rate, pH value, total number of colonies, total volatile base nitrogen and thiobarbituric acid reactive substance values. The present study will provide a theoretical basis for the application of LCPS as new biodegradable active films.

Influence of genotypes and crop growth stage at time of infection on seed transmission of Maize chlorotic mottle virus

Understanding the effect of seed transmission of Maize chlorotic mottle virus (MCMV) is important in managing the spread of the disease especially secondary transmission caused by vectors. This study was set out to investigate the effect of different genotypes and crop growth stage at the time of infection to rate of MCMV transmission from seeds to seedlings. The experiments were laid out in randomised complete block design with three replications. Detection of MCMV in the grow outs was determined using double antibody sandwich enzyme-linked immunosorbent assay and real time reverse transcription polymerase chain reaction. The results showed low rates of seed transmission from the genotypes in which their was detection of MCMV in their samples (0.08–1%). Similarly, crop growth stage at time of infection also showed low transmission rate of up to 0.1%, with highest transmission rate at the four-leaf stage.

Hybrid organic-inorganic coating with enhanced oxygen- and UV-barrier performance: Polyelectrolyte complex based on sodium alginate, poly (vinyl alcohol), and reconstructed layered double hydroxide

Organic-inorganic hybrid materials with high oxygen- and UV-barrier properties were developed using a polyelectrolyte complex comprising sodium alginate (SA), poly (vinyl alcohol) (PVA), and reconstructed layered double hydroxide (RLDH). These materials were applied to poly (ethylene terephthalate) (PET) as a barrier coating layer at a harsh drying temperature of 120 °C, similar to environments for the industrial coating process. The RLDH nanoplatelets within the coating matrix restricted the polymer chain mobility, elevating the glass transition temperature to 105.222–159.114 °C. Below RLDH 0.2 %, the apparent coating density significantly increased to 0.93–0.94 g/cm3. The embedded RLDH gave a tortuosity within the matrix, as evidenced by an intensified (003) diffraction peak in the XRD analysis. These structural alterations contributed to high oxygen- and UV-barrier performance. Notably, the PET/SA1.0PVA0.5RLDH0.2 film exhibited an extremely low oxygen transmission rate of <0.005 cm3/m2·day, with effectively blocking UV-A (62.41 %), -B (92.45 %), and -C light (100 %). Moreover, the susceptibility of the coated film to water vapor was mitigated by laminating cast polypropylene, achieving a water vapor transmission rate of 1.17 g/m2·day. Overall, the packaging materials with advanced oxygen-, water vapor-, and UV-barrier properties show great potential for practical applications in various sectors, including food packaging and medical/electrical devices.

A novel antioxidant and antimicrobial food packaging based on Eudragit ®/collagen electrospun nanofiber incorporated with bitter orange peel essential oil

A novel nanofiber for potential use in food packaging was developed by blending Eudragit ® (Eu) and collagen (Co) at varying ratios. Among these blends, Eu/Co nanofiber with a 70:30 ratio was identified as the optimal composition due to its bead-free morphology, fine fiber diameter (279.6 nm), high tensile stress (6.9 MPa), desirable water contact angle (WCA) of 72.18°, low water vapor transmission rate (WVTR) of 423.51 g/m2 × 24 h, and favorable porosity (65.4%). To further enhance its properties, bitter orange peel essential oil (BE) (up to 100 μL/mL) was incorporated into the optimal blend, resulting in a reduced fiber diameter (211.6 nm), increased tensile stress (8.5 MPa), and enhanced porosity (73.5%). Moreover, BE induced potential antimicrobial and antioxidant activities in the nanofibers, effectively inhibiting the growth of E. coli and S. aureus bacteria while scavenging up to 50% of DPPH radicals, respectively. Importantly, none of the nanofiber samples exhibited cytotoxicity toward Human umbilical vein endothelial cells (HUVEC) over a 72-h period, demonstrating their biocompatibility. These findings highlight the suitability of Eu and Co-based nanofibers enriched with bioactive compounds like BE for use in food packaging applications.

High-income ZIP codes in New York City demonstrate higher case rates during off-peak COVID-19 waves.

Our study explores how New York City (NYC) communities of various socioeconomic strata were uniquely impacted by the COVID-19 pandemic. New York City ZIP codes were stratified into three bins by median income: high-income, middle-income, and low-income. Case, hospitalization, and death rates obtained from NYCHealth were compared for the period between March 2020 and April 2022. COVID-19 transmission rates among high-income populations during off-peak waves were higher than transmission rates among low-income populations. Hospitalization rates among low-income populations were higher during off-peak waves despite a lower transmission rate. Death rates during both off-peak and peak waves were higher for low-income ZIP codes. This study presents evidence that while high-income areas had higher transmission rates during off-peak periods, low-income areas suffered greater adverse outcomes in terms of hospitalization and death rates. The importance of this study is that it focuses on the social inequalities that were amplified by the pandemic.

Development and Characterization of Edible Packaging Film Using Lignin Extracted from Coffee Silverskin

In this study, edible packaging films were developed by solvent casting method using lignin extracted from Costa Rican or Kenyan coffee silverskin and their barrier properties were investigated. Anise or cinnamon essential oil, glycerol or sorbitol or polyethylene glycol, and sodium alginate effects on the film properties were compared. The moisture content, swelling index and water vapor transmission rate analyses of the produced edible films were realized. Chemical structure analysis was done using Fourier Transform Infrared Spectroscopy device. Edible films plasticized with glycerol, have higher moisture content (23.21%), low swelling index (28.44%) and low water vapor transmission rate (0.7991*10-8(g/cm2.s)), than the films plasticized with sorbitol and polyethylene glycol. As a result, it was observed that coffee processing waste coffee silverskin, plasticized in preference with glycerol and mixed with anise or cinnamon essential oil, can be successfully used as a cost-effective lignin source for edible packaging film production.

Surviving the summer: foot-and-mouth disease virus survival in U.S. regional soil types at high ambient temperatures.

Foot-and-mouth disease (FMD) is one of the most economically significant global livestock diseases. In the U.S., economic optimization models run in 2011 demonstrate the highest mean epidemic impact of a potential FMD outbreak in California would occur in livestock-dense regions, resulting in national agriculture losses of $2.3 to $69.0 billion. In the case that an FMD outbreak occurred in the U.S., mass depopulation, carcass disposal, and disinfection protocols for infected premises have been designed to prevent further viral spread. Because the FMD virus (FMDV) is spread mechanically via the environment, characteristics of viral environmental stability are important. Temperature and adsorption to soil particles are reported to be the most important factors affecting general virus survival; however, how much these factors alter FMDV survival has not been tested. Soil samples were examined from typical U.S. regions containing the highest cattle population densities: Tennessee, Georgia, Nebraska, California, Pennsylvania, Kentucky, and Iowa. Soils were spiked with known quantities of FMDV and FMDV stability was evaluated over seven distinct time points between 0 hours and 12 days at incubation temperatures of 25°C and 37°C to represent a range of typical ambient temperatures during the summer. FMDV stability was quantified via virus titration. Virus decayed faster at higher ambient temperatures for all soils, but decay at 25°C was faster in some soils. Consequently, areas with high ambient temperatures may have lower between-farm transmission rates, slower outbreak spread, and simpler farm decontamination. This study provides a helpful exploration into understanding soil survival of the virus. Additional investigations into FMDV survival across different soil types will aid in developing better disinfection protocols and further refining regional viral transmission rate estimates.

The burden of dengue in children and risk factors of transmission in nine districts in Sri Lanka

AbstractWe sought to understand the differences in age‐stratified seroprevalence rates in different regions in Sri Lanka to plan dengue vaccination programs, especially as the WHO has given guidance to vaccinate in high transmission settings. Age stratified seroprevalence rates were assessed in children, aged 10−20 years, in nine districts representing the nine provinces in Sri Lanka, from September 2022 to March 2023. A stratified multistage cluster was used to select 146 schools representing each district. Of the 5207 children recruited, the overall dengue seroprevalence rates in children was 24.8%, with the highest rates reported from Trincomalee (54.3%) and the lowest rates from Badulla (14.2%), which is a high‐altitude estate area. While the age‐stratified seroprevalence rates increased in some districts such as Trincomalee, Jaffna, Gampaha, and Ratnapura, which reported the highest seropositivity rates, there was no such increase with age in the other districts. There was a weak correlation between the dengue antibody positivity rates and age in most districts which had seroprevalence rates of &gt;25%, while there was no increase in antibody titers with age in the other districts. The seroprevalence rates was significantly higher in urban areas (35.8%) compared to rural (23.2%) and estate areas (9.4%), although there was no association with seropositivity rates with population density (Spearman's r = −0.01, p = 0.98), in each district. The seroprevalence rates in many districts were very different to those reported from Colombo, with many districts reporting low transmission rates. These data would be important to consider when rolling out dengue vaccines in Sri Lanka.

Polyisobutylene Encapsulated PEDOT: Pss Electrode Honeycomb Skeleton Electrolyte for Moisture Resistant Electro‐Ionic Soft Artificial Muscles

AbstractAdvances in electro‐ionic soft actuators hold significant potential as next‐generation bioelectronic interfaces due to mechanical compliance and operation in agreement with soft biological tissues and low voltages. However, current devices call for encapsulation strategies to accommodate high mechanical demands and long‐term stability in environmental changes. In this study, a durability of polyvinylidene‐fluoride‐co‐hexafluoropropylene (PVDF‐co‐HFP) honeycomb skeleton electrolyte encapsulated with a biocompatible polyisobutylene (PIB) thin film is being investigated. A low water vapor transmission rate (0.61 g m−2 day−1) and elastic modulus (10 kPa) are measured from a 7.5 µm‐thick thin‐modified PIB‐encapsulation layer. The PIB‐encapsulated soft actuator maintains 68% of its mechanical durability after 40 000 cycles of zero‐to‐tension fatigue loading at room temperature. A cantilever actuation test of the PIB‐encapsulated 3mm‐wide 30mm‐long actuator film shows a large tip displacement (15.90 mm) at a low voltage (±1.5 V) under 0.1 Hz, 37 °C, 50% relative humidity (RH). Most importantly, while the unencapsulated actuator immediately degrades in a few cycles at 37 °C, 50%RH, and 0.1% applied strain, PIB‐encapsulated soft actuator performs up to 6500 dynamic actuation cycles without any functionality degradation. Exceptional durability against mechanical fatigue and stability at elevated temperature and humidity meet the prerequisite for future soft biomedical robots that enable long‐lasting safe operations.

Potential‐induced degradation in bifacial silicon heterojunction solar modules: Insights and mitigation strategies

AbstractPotential‐induced degradation (PID) may be a serious concern in photovoltaic (PV) modules and plants, particularly when approaching high system voltages (1500+ V). Here, we investigate PID occurring in bifacial rear‐emitter silicon heterojunction (SHJ) solar cells encapsulated in a glass/glass (G/G) module configuration with ethylene vinyl acetate (EVA) as an encapsulant. PID testing was performed at 85°C in 85% relative humidity (RH), and the solar cells were subjected to −1 kV and +1 kV for up to 800 h. SHJ cells were found to degrade when subjected to −1 kV, and to a lesser extent when left unbiased in damp heat (DH) conditions, while the application of +1 kV prevented degradation. Although prone to PID after extended test durations, the SHJ mini‐modules investigated in this study noticeably passed the industry standard (IEC 61215:2021) PID test of 96 h. The degradation was primarily characterized by losses in short‐circuit current (ISC) at the front side, followed by fill factor (FF) and open‐circuit voltage (VOC). A cross‐sectional transmission electronic microscopy analysis of the laminates subjected to −1 kV highlighted a transport of sodium (Na) through the transparent conductive oxide (TCO), reaching the amorphous Si/TCO interface. The samples tested in DH conditions and with positive PID test conditions did not exhibit such a migration of Na. To account for these observations, we updated a previously proposed model describing the sensitivity of SHJ cells to water. In our degradation model, moisture in the module corrodes the glass, creating sodium hydroxide (NaOH) that then percolate through the EVA before reaching the SHJ cell. The application of a high negative bias amplifies the previous mechanism by increasing the availability of Na+ and also enhances the drift of Na+ through the EVA to the cell. Finally, we demonstrate that PID can be mitigated or suppressed at the module level by using a high‐volume resistivity encapsulant with a low water vapor transmission rate (WVTR) or by encapsulating SHJ solar cells in a configuration impermeable to water (e.g., using an edge sealant).

Delayed Response and Random Backoff First for Low-Power Random Access of IoT Devices with Poor Channel Conditions

As IoT services become more active, the density of IoT devices is increasing, and massive connectivity technology is needed to support numerous devices simultaneously. In addition, IoT devices are often battery-powered, and during random access, it is necessary to reduce the power consumption to extend the lifetime of the devices. In particular, devices with poor channels need to send at a very low transmission rate through a large number of repetitions, and longer packet lengths can increase the probability of collisions, increasing the power consumption while shortening the lifetime of the IoT system. Dividing devices into groups based on the number of repetitions and allocating different resources to each group can reduce collisions for bad-channel devices, but it can be difficult to support large connections, due to the inefficient use of resources. This paper proposes schemes to reduce the collision probability of bad-channel devices while allowing IoT devices to use shared resources, instead of dividing resources by groups. There are two versions of the proposed schemes. The first method reduces collisions by delaying the response of a bad-channel device, and in the meantime, eliminating interference from other devices, assuming that the bad-channel device is not sensitive to delay. Instead of checking the response, and then, performing a random backoff when no acknowledgement packet is received, the second proposed method reverses the order of response checking and random backoff, that is, it first performs a random backoff, and then, checks the response to decide whether to retransmit. The proposed method can increase the lifetime of the IoT system by reducing the collision probability of a bad-channel device, without degrading the performance of other devices.

Anti-Attack Event-Triggered Control for Nonlinear Multi-Agent Systems With Input Quantization.

In this article, an anti-attack event-triggered secure control scheme for a class of nonlinear multi-agent systems with input quantization is developed. With the help of neural networks approximating unknown nonlinear functions, unknown states are obtained by designing an adaptive neural state observer. Then, a relative threshold event-triggered control strategy is introduced to save communication resources including network bandwidth and computational capabilities. Furthermore, a quantizer is employed to provide sufficient accuracy under the requirement of a low transmission rate, which is represented by the so-called a hysteresis quantizer. Meanwhile, to resist attacks in the multi-agent network, a predictor is designed to record whether an edge is attacked or not. Through the Lyapunov analysis, the proposed secure control protocol can ensure that all the closed-loop signals remain bounded under attacks. Finally, the effectiveness of the designed scheme is verified by simulation results.

IoT Sea Level Monitoring Development and Field Testing Study

The measurement of sea level is essential to oceanography because it provides vital information about the ocean environment, such as tides, currents, and water temperature. This research aimed to develop an Internet of Things (IoT)-based sea level monitoring device that can precisely measure sea level and transmit data in real time. An ESP32 microcontroller, a GSM module, an MS5803-14BA sensor, and a battery constituted the device. To protect the electronics from the ocean environment, the components were assembled on a PCB board and placed within a waterproof box. The field test was conducted for 17 hours at the Class 1 Navigation Office Port in Tanjungpinang, and the Ubidots platform was used to monitor the data. The device accurately measured sea level with an RMSE of 0.69 cm and an accuracy rate of 99.47%, according to the results. However, the field test also revealed problems with data transmission, with 18.81% of the data not being transmitted to the server. This low data transmission rate may have been caused by low RSSI levels and signal quality issues with the operator. To understand the causes of these data losses and improve the device's overall performance, additional research is required. This study demonstrated the viability of utilizing an Internet of Things-based sea level monitoring device to precisely measure sea level and transmit data in real time. It provides valuable information for the improvement and further development of sea level monitoring systems.

Prenatal ultrasound screening and pregnancy outcomes in HIV-positive women in Germany: results from a retrospective single-center study at the Charité-Universitätsmedizin Berlin.

The aim of this study was to investigate the rate of Mother-to-child-transmission (MTCT) in women living with HIV (WLWH) in a tertiary care institution. Furthermore, we aimed to assess prenatal ultrasound screening for fetal anomalies and outcomes in high-risk pregnancies due to maternal HIV infection." In this single-center study, retrospective data related to pregnancy and childbirth were collected from 420 WLWH. All data were evaluated descriptively. From January 2014 to December 2020, a total number of 420 pregnant WLWH delivered 428 newborns. 415 (98.8%) were receiving antiretroviral therapy (ART) and 88.8% had a viral load of < 50 cop/ml prior delivery. 46 (11%) of the newborns were born prematurely. Low birth weight < 2500g occurred in 38 (9.1%) of the children. 219 (52.1%) caesarean sections (CS) were performed. The most frequent indication for an elective CS was a previous CS (70.2%). 8 severe malformations were detected using first and second trimester ultrasound. In one child, MTCT was detected postpartum, resulting in an HIV transmission rate of 0.2% in the presented cohort. The low rate of vertical HIV-transmission in our cohort of 0.2% is the result of interdisciplinary prenatal care and high experience of healthcare providers in treatment of WLWH. Despite high ART coverage and adherence, good maternal immune system and very low vertical HIV transmission rate, maternal HIV infection remains a challenge in obstetric care. First and second ultrasound screening should be a part of prenatal care for HIV-infected women and should also be offered to HIV-negative women. A reduction of the rate of unnecessary elective caesarean deliveries in WLWH is necessary to reduce complications in subsequent pregnancies.

An investigation into the transmission and control of pestivirus in sheep in Australia.

Border disease virus (BDV) is a member of the pestivirus genus that primarily affects sheep, causing reproductive losses through abortion, still births and the birth of weak lambs. The key characteristic of this disease is the birth of persistently infected (PI) lambs which, after surviving transplacental infection, are born antibody negative, yet virus positive, and thus shed the virus for their entire life and are the primary source of spread within a flock. The cornerstones of BDV control are detection and elimination of PI animals, biosecurity measures to prevent re-infection, and surveillance programs. Recommendations for the control of BDV in sheep are centred around the approach to bovine viral diarrhoea virus (BVDV), the prominent cattle pestivirus species, due to a lack of specific research into BDV control and elimination. In this study, two aspects of a BDV control program were investigated: the effectiveness of the BVDV vaccine, Pestigard®, and the rate of seroconversion in a flock deliberately exposed to known PI lambs. The vaccine appeared to be safe, and the optimal dose was the full cattle dose (2 mL). While vaccination induced high virus neutralising titres to BVDV when administered as either a quarter, half or full dose registered for cattle, the BDV titres achieved were low and unlikely to prevent transplacental infection. In a second study, after exposure of between 2 and 15 days exposure to two PI lambs in confined conditions, only 3 of 66 previously naïve sheep demonstrated seroconversion. This demonstrated a very low rate of transmission and suggested that deliberate exposure to PI lambs at low-risk times for less than 15 days was not likely to be an effective means of achieving seroconversion throughout a flock and, therefore, not provide protection against BDV challenge during gestation.

Plasticizer concentration effect on films and coatings based on poly(vinyl alcohol) and cationic starch blends

Films based on poly(vinyl alcohol) (PVA) and cationic starch (CS) were combined with different percentages of sorbitol (S; 15.0, 22.5, and 30.0% w v-1) to assess the effect of plasticizer on the films. Spectroscopic analyses confirmed the interaction between them. However, micrographs indicated the formation of sorbitol crystals on the surface of the films, especially at higher sorbitol concentrations. The blends presented low water vapor transmission rate values, reaching (7.703 ± 0.000) g h−1 m−2 (PVA75CS25S15), and low solubility values for the films containing higher CS amounts. The lack of statistical differences in most parameters suggests that no significant gain comes from increasing the amount of sorbitol at percentages higher than 15%. As a coating, the blend PVA75CS25S15 successfully decreased the loss of moisture content in acerolas by 1.15 times (compared to the control), confirming the suitability of this matrix as a fruit coating.

Study of the Physical, Chemical, and Structural Properties of Low- and High-Methoxyl Pectin-Based Film Matrices Including Sunflower Waxes.

The development of bio-based materials remains one of the most important alternatives to plastic materials. Although research in this field is growing, reporting various materials and methodologies, it is still necessary to increase exploration. The aim of this work was to expand and complement previous research on the preparation and characterization of high- and low-methoxyl pectin films obtained by casting, with the addition of commercial and recovered sunflower waxes. The results showed that the addition of sunflower waxes to the pectin matrix generated some discontinuity in the aggregate, increasing the thickness and roughness of the film. However, due to their hydrophobic nature, the waxes contributed to lower vapor transmission rate values of the films. On the other hand, the low-methoxyl pectin films had a more crystalline structure, which could help to diminish water vapor permeability values, mechanical resistance and rigidity, and improve their elongation. Regarding chemical characteristics, most of the raw materials' chemical groups were found in the resulting films, and the presence of C-H bending due to pectin gelation was observed. Finally, the compatibility and contribution of pectin and sunflower waxes to the production of the films were demonstrated, as well as the possibility of using materials from industrial waste in food packaging applications.