A control framework to optimize public health policies in the course of the COVID-19 pandemic.

The SARS-CoV-2 pandemic triggered substantial economic and social disruptions. Mitigation policies varied across countries based on resources, political conditions, and human behavior. In the absence of widespread vaccination able to induce herd immunity, strategies to coexist with the virus while minimizing risks of surges are paramount, which should work in parallel with reopening societies. To support these strategies, we present a predictive control system coupled with a nonlinear model able to optimize the level of policies to stop epidemic growth. We applied this system to study the unfolding of COVID-19 in Bahia, Brazil, also assessing the effects of varying population compliance. We show the importance of finely tuning the levels of enforced measures to achieve SARS-CoV-2 containment, with periodic interventions emerging as an optimal control strategy in the long-term.

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.

Study of interactions between organic contaminants and a new phosphated biopolymer derived from cellulose.

The extensive use of organic molecules (Rhodamine B and Amitriptyline) also has contributed to environmental pollution; adsorption is a relevant method for removal of these contaminants in aqueous media. In this context, the objective of this study was to modify the surface of cellulose (Cel) with phosphoric acid and sodium tripolyphosphate to obtain a biopolymer with incorporated phosphate groups (PCel). The modification was confirmed by X-ray dispersive energy spectroscopy, solid state nuclear magnetic resonance, X-ray diffraction, and thermal analysis. The obtained material (PCel) was used as a Rhodamine B (RhB) or Amitriptyline (AmTP) adsorbent, and the highest adsorption capacity of this material was obtained at pH 3.0 (RhB) and 7.0 (AmTP) and the equilibrium time was achieved at 65 (RhB) and 150 min (AmTP). Moreover, the pseudo-first-order model best describes the kinetics of this adsorption. The experimental adsorption isotherms were adjusted to the Langmuir model, indicating that monolayer adsorption occurred and the highest experimental adsorption capacity obtained was 47.58 (RhB) and 45.52 mg g-1 (AmTP) in PCel. The thermodynamic parameters showed that the adsorption process is exothermic and non-spontaneous, with increase of non-spontaneity with enhance of the temperature. However, PCel was efficient in removing the contaminant (RhB or AmTP) in an aqueous solution.

Understanding kinetics and thermodynamics of the interactions between amitriptyline or eosin yellow and aminosilane-modified cellulose.

A new adsorbent matrix (Cel-SiN) for the adsorption of the dye eosin yellow (EY) and the drug amitriptyline (AMI) from aqueous media has been synthesized. The Cel-SiN matrix was obtained via chemical modification of cellulose with (3-aminopropyl)trimethoxysilane. Successful modification was confirmed using Fourier transform infrared (FTIR) and 13C and 29Si solid state nuclear magnetic resonance (SSNMR) spectroscopies, thermal analysis (TG/DTG), X-ray diffraction (XRD), and elemental analysis. The effects of pH, contact time, concentration, and temperature were evaluated in batch adsorption tests. Cel-SiN efficiently adsorbed AMI and EY in aqueous media, with maximum adsorption capacities of 92.28 ±â€¯1.34 mg g-1 for AMI (pH = 7, time =240 min, and temperature = 318 K) and 61.0 ±â€¯0.36 mg g-1 for EY (pH = 5, time =80 min, and temperature = 298 K). The adsorption process occurs mainly via hydrogen bonding interactions for AMI and electrostatic interactions for EY.

Potential of amino-functionalized cellulose as an alternative sorbent intended to remove anionic dyes from aqueous solutions.

Adsorption has been explored to minimize the pollution caused by dyes. This work relates the preparation of diethylenetriamine-modified cellulose (DetaCel) by reacting phthalic anhydride-modified cellulose (PhCel) with diethylenetriamine (Deta). Materials were characterized by Elemental Analysis and results showed a degree of incorporation of 5.55 ±â€¯0.02 mmol of nitrogen per gram of modified material. The main bands observed for DetaCel by Fourier-Transform Infrared Spectroscospy (FTIR) were attributed to CN deformation (1330 cm-1) and NH stretching of amide (3400 cm-1), while Solid State Nuclear Magnetic Resonance of 13C (13C{1H}CP-MAS NMR) showed a signal at 164.6 ppm characteristic of amide group. Crystallinity index (CrI) obtained by X-Ray Diffraction (XRD) was 74.99 (Cel), 58.64 (PhCel) and 46.12% (DetaCel). Adsorbent matrices were employed to remove methyl orange (MO) and eosin (EY) dyes in aqueous medium. Data obtained experimentally from kinetic study had a better fit to the pseudo-first order, thus the adsorption process occurs in monolayer, with MO adsorption capacity by Cel and DetaCel of 2.19 and 65.45 mg g-1, respectively. For EY adsorption by Cel and DetaCel was 1.30 and 56.69 mg g-1, respectively. These results suggest that DetaCel can be used as an alternative potential for removal dyes in aqueous solution.

Direct Modification of Microcrystalline Cellulose with Ethylenediamine for use as Adsorbent for Removal Amitriptyline Drug from Environment.

Cellulose derivatives have been widely used as adsorbents for the removal of micropollutants such as drugs, dyes, and metals, due to their abundance, low cost and non-contaminating nature. In this context, several studies have been performed searching for new adsorbents (cellulose derivatives) efficient at contaminant removal from aqueous solutions. Thus, a new adsorbent was synthesized by chemical modification of cellulose with ethylenediamine in the absence of solvent and applied to the adsorption of amitriptyline (AMI) in aqueous solution. The modification reaction was confirmed by X-ray Diffraction (XRD), elemental analysis, Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetry/Differential Scanning Calorimeter (TG/DSC), solid state Nuclear Magnetic Resonance of ¹H and 13C (¹H-NMR and 13C-NMR). Moreover, the effectiveness of reaction was confirmed by computational calculations using Density Functional Theory (DFT) at level B3LYP/6-31G(d). This adsorption process was influenced by pH, time, concentration, temperature and did not show significant changes due to the ionic strength variation. Through these experiments, it was observed that the maximum adsorption capacity of AMI by CN polymer at 298 K, 300 min, and pH 7 was 87.66 ± 0.60 mg·g-1.