Films of Poly(Hydroxybutyrate) (PHB) and Copper with Antibacterial Activity.

Poly(3-hydroxybutyrate), PHB, is a hydrophobic biopolymer with good mechanical and barrier properties. However, neat PHB is a semicrystalline polymer with a relative high degree of crystallinity and poor film properties. In this work, this biopolymer was plasticized with glycerol tributyrate and functionalized with copper (II) sulfate, allowing us to obtain biodegradable antimicrobial flexible films. Films with the minimum inhibitory concentration (MIC) of copper (II) sulfate presented a higher roughness than neat PHB films. The presence of plasticizer significantly improved the copper sulfate diffusion process, which was evidenced by a greater inhibition halo for plasticized materials compared to unplasticized ones, at the same salt concentration. Plasticized PHB with 2.5% copper (II) sulfate inhibited both Gram-positive (Staphylococcus aureus) and Gram-negative (Pseudomona aeruginosa) bacteria, as determined by the bacterial inhibition halo. In addition, neat PHB films and PHB containing copper (II) sulfate did not show in vitro cytotoxicity in the L-929 cell line. Thus, plasticized PHB functionalized with copper (II) sulfate can be used as biodegradable antimicrobial flexible films for different applications.

Sustainable and Bio-Based Food Packaging: A Review on Past and Current Design Innovations.

Food loss and waste occur for many reasons, from crop processing to household leftovers. Even though some waste generation is unavoidable, a considerable amount is due to supply chain inefficiencies and damage during transport and handling. Packaging design and materials innovations represent real opportunities to reduce food waste within the supply chain. Besides, changes in people's lifestyles have increased the demand for high-quality, fresh, minimally processed, and ready-to-eat food products with extended shelf-life, that need to meet strict and constantly renewed food safety regulations. In this regard, accurate monitoring of food quality and spoilage is necessary to diminish both health hazards and food waste. Thus, this work provides an overview of the most recent advances in the investigation and development of food packaging materials and design with the aim to improve food chain sustainability. Enhanced barrier and surface properties as well as active materials for food conservation are reviewed. Likewise, the function, importance, current availability, and future trends of intelligent and smart packaging systems are presented, especially considering biobased sensor development by 3D printing technology. In addition, driving factors affecting fully biobased packaging design and materials development and production are discussed, considering byproducts and waste minimization and revalorization, recyclability, biodegradability, and other possible ends-of-life and their impact on product/package system sustainability.

Breeding system and geospatial variation shape the population genetics of Triodanis perfoliata.

Both intrinsic and extrinsic forces work together to shape connectivity and genetic variation in populations across the landscape. Here we explored how geography, breeding system traits, and environmental factors influence the population genetic patterns of Triodanis perfoliata, a widespread mix-mating annual plant in the contiguous US. By integrating population genomic data with spatial analyses and modeling the relationship between a breeding system and genetic diversity, we illustrate the complex ways in which these forces shape genetic variation. Specifically, we used 4705 single nucleotide polymorphisms to assess genetic diversity, structure, and evolutionary history among 18 populations. Populations with more obligately selfing flowers harbored less genetic diversity (π: R 2 = .63, p = .01, n = 9 populations), and we found significant population structuring (F ST = 0.48). Both geographic isolation and environmental factors played significant roles in predicting the observed genetic diversity: we found that corridors of suitable environments appear to facilitate gene flow between populations, and that environmental resistance is correlated with increased genetic distance between populations. Last, we integrated our genetic results with species distribution modeling to assess likely patterns of connectivity among our study populations. Our landscape and evolutionary genetic results suggest that T. perfoliata experienced a complex demographic and evolutionary history, particularly in the center of its distribution. As such, there is no singular mechanism driving this species' evolution. Together, our analyses support the hypothesis that the breeding system, geography, and environmental variables shape the patterns of diversity and connectivity of T. perfoliata in the US.

Gels based on calcium alginate/pillared bentonite: structural characterization and their use as cadmium removal agent.

In this work, calcium alginate hydrogels with natural and pillared bentonites (0.5 and 5% w/w) were synthetized in two geometries (disks and beads) and their capacity to adsorb cadmium ion from aqueous media was evaluated. Pillarization effect on bentonite morphology was evidenced by SEM, XRD, LD and BET isotherms. Structure and swelling capacity of hydrogels were determined, showing that hydrogels beads with pillared clays presented the higher ability to retain water. Regarding cadmium adsorption capacity, the effect of pH media (3, 5 and 7), the contact time (0 to 320 min.) and the initial cadmium ion concentration (6 to 42 mg/L) were studied employing hydrogel beads. Regardless bentonite type and concentration, the optimal pH cadmium adsorption was 7, reaching the highest adsorption capacity (93%) for hydrogel with 0.5% natural bentonite. Besides, the equilibrium adsorption time was reached at 120 min for all studied hydrogels and experimental data fitted with a pseudo-second order kinetic model.

Biobased composites from agro-industrial wastes and by-products.

The greater awareness of non-renewable natural resources preservation needs has led to the development of more ecological high-performance polymeric materials with new functionalities. In this regard, biobased composites are considered interesting options, especially those obtained from agro-industrial wastes and by-products. These are low-cost raw materials derived from renewable sources, which are mostly biodegradable and would otherwise typically be discarded. In this review, recent and innovative academic studies on composites obtained from biopolymers, natural fillers and active agents, as well as green-synthesized nanoparticles are presented. An in-depth discussion of biobased composites structures, properties, manufacture, and life-cycle assessment (LCA) is provided along with a wide up-to-date overview of the most recent works in the field with appropriate references. Potential uses of biobased composites from agri-food residues such as active and intelligent food packaging, agricultural inputs, tissue engineering, among others are described, considering that the specific characteristics of these materials should match the proposed application.

An Explainable Machine Learning Approach Based on Statistical Indexes and SVM for Stress Detection in Automobile Drivers Using Electromyographic Signals.

The economic and personal consequences that a car accident generates for society have been increasing in recent years. One of the causes that can generate a car accident is the stress level the driver has; consequently, the detection of stress events is a highly desirable task. In this article, the efficacy that statistical time features (STFs), such as root mean square, mean, variance, and standard deviation, among others, can reach in detecting stress events using electromyographical signals in drivers is investigated, since they can measure subtle changes that a signal can have. The obtained results show that the variance and standard deviation coupled with a support vector machine classifier with a cubic kernel are effective for detecting stress events where an AUC of 0.97 is reached. In this sense, since SVM has different kernels that can be trained, they are used to find out which one has the best efficacy using the STFs as feature inputs and a training strategy; thus, information about model explain ability can be determined. The explainability of the machine learning algorithm allows generating a deeper comprehension about the model efficacy and what model should be selected depending on the features used to its development.

Vinasse: from a residue to a high added value biopolymer.

This work aimed to study the feasibility of using vinasse for polyhydroxybutyrate (PHB) production by Bacillus megaterium. To optimize the culture medium, a Box-Behnken design was employed considering carbon (C), nitrogen (N), and phosphorus (Ph) concentrations as independent variables and PHB productivity as the response variable. The productivity decreased when C or N were increased, probably due to the presence of phenolic compounds and the limitation of N for the production of PHB by Bacillus sp. bacteria. An additional experimental design to optimize the C/N ratio and growing conditions (fermentation time and temperature) was carried out. Fermentation time had a statistically significant effect on PHB productivity reaching 10.6 mg/L h. On the other hand, the variability in physicochemical properties of vinasse samples led to significant differences in PHB productivity. Lower productivity values were obtained when vinasse had higher values of DBO. Therefore, biopolymers production from vinasse is a feasible alternative to valorize this bioethanol by-product.

Reduction of spermatophore melanization in Litopenaeus vannamei shrimp fed Ulva clathrata during a commercial hatchery production.

Male broodstock (Litopenaeus vannamei, 36 ± 7 g, n = 600) reproductive performance, spermatophores and reproductive tract melanization, prostaglandin concentrations and biochemical composition were evaluated after including 3.8% Ulva clathrata meal in the diet (dry base) of a commercial hatchery during 45 days. Males fed Ulva had less melanized spermatophores (120 compared with 233, P < 0.01), less bacteria in the ductus deferens (P < 0.01), more sperm cells in testicles (P < 0.05), and increased courtship activity (839 compared with 689, P < 0.01), with no effect on mortality. Ulva-fed males had more arachidonic acid (20:4n-6) in the spermatophores (P < 0.05) but this did not affect the prostaglandin concentrations in response to diet. Males fed Ulva had more carotenoids in the hepatopancreas (0.08 ± 0.02 compared with 0.01 ± 0.01 mg/g, P < 0.05), and phenolic compounds in hepatopancreas (6.1 ± 0.7 compared with 1.8 ± 0.7 mg eq. phloroglucinol/g, P < 0.05) and muscle (0.4 ± 0.3 compared with 0.2 ± 0.1 mg eq. phloroglucinol/g, P < 0.05). Males fed the Ulva also had a lesser carbohydrate content in the hepatopancreas (P < 0.01) and muscle (P < 0.01). In conclusion, supplementing fresh maturation diets with a small dose of dried Ulva allowed for improvement of reproductive performance and to decrease melanization in spermatophores and the male reproductive tract.

A New Methodology Based on EMD and Nonlinear Measurements for Sudden Cardiac Death Detection.

Heart diseases are among the most common death causes in the population. Particularly, sudden cardiac death (SCD) is the cause of 10% of the deaths around the world. For this reason, it is necessary to develop new methodologies that can predict this event in the earliest possible stage. This work presents a novel methodology to predict when a person can develop an SCD episode before it occurs. It is based on the adroit combination of the empirical mode decomposition, nonlinear measurements, such as the Higuchi fractal and permutation entropy, and a neural network. The obtained results show that the proposed methodology is capable of detecting an SCD episode 25 min before it appears with a 94% accuracy. The main benefits of the proposal are: (1) an improved detection time of 25% compared with previously published works, (2) moderate computational complexity since only two features are used, and (3) it uses the raw ECG without any preprocessing stage, unlike recent previous works.

Crystalline morphology of thermoplastic starch/talc nanocomposites induced by thermal processing.

A structural study about the changes induced by plasticization of native corn starch was carried out in this work. The influence of talc nanoparticles presence during starch thermal processing was also evaluated. Macroscopic observation of the granules appearance evolution during melt-mixing and thermo-compression was supported by a theoretical description related to these processing methods. Melt-mixing induced a polymorphic transformation from A- to Vh-type and a reduction in the degree of crystallinity. Homogenous appearance of the plasticized starch was in accordance to the disruption of granules integrity, evidenced by SEM. This observation agreed to the distinctive XRD pattern of plasticized starch from unprocessed granules. Talc incorporation did not require the adjustment of processing parameters in order to obtain a homogenous thermoplastic material, with an adequate particles distribution within the matrix. Regardless talc presence, plasticized starch presented a Vh-type crystalline structure. Thermo-compression led to particles alignment promoted by talc laminar morphology.

Enhancement of thermoplastic starch final properties by blending with poly(ɛ-caprolactone).

Final properties of two thermoplastic corn starch matrices were improved by adding poly(ɛ-caprolactone), PCL, at 2.5, 5, and 10% w/w. One of the thermoplastic starch matrices was processed using water and glycerol as plasticizers (SG) and the other one was plasticized with a mixture of glycerol and sodium alginate (SGA). Blends were suitably processed by melt mixing and further injected. Films obtained by thermo-compression were flexible and easy to handle. Microstructure studies (SEM and FTIR) revealed a nice distribution of PCL within both matrices and also a good starch-PCL compatibility, attributed to the lower polyester concentration. The crystalline character of PCL was the responsible of the increment in the degree of crystallinity of starch matrices, determined by XRD. Moreover, it was demonstrated by TGA that PCL incorporation did not affect the thermal stability of these starch-based materials. In addition, a shift of Tg values of both glycerol and starch-rich phases to lower values was determined by DSC and DMA tests, attributed to the PCL plasticizing action. Besides, PCL blocking effect to visible and UV radiations was evident by the incremented opacity and the UV-barrier capacity of the starch films. Finally, water vapor permeability and water solubility values were reduced by PCL incorporation.

Thermoplastic starch plasticized with alginate-glycerol mixtures: Melt-processing evaluation and film properties.

Corn starch melt-processing in the presence of a commonly used plasticizer mixture (water/glycerol) and a non-conventional alternative (alginate/glycerol) was evaluated. All assayed formulations were successfully processed by melt-mixing and injected in circular probes. It was determined that all samples presented a typical viscoelastic behavior, observing a decrease in storage and loss modulus with water and alginate concentration, which facilitated samples processability. Concerning to thermal stability, it was not affected neither for water nor alginate presence. From injected probes, flexible films were obtained by thermo-compression. Films with the highest assayed water content presented a sticky appearance, whereas those containing alginate were non-tacky. Plasticizing action of water and alginate was evidenced by the occurrence of homogeneous fracture surfaces, without the presence of unmelted starch granules. Besides, the shift of glass transition temperature to lower values also corroborated the plasticizing effect of both additives. In conclusion, obtained results demonstrated the well-plasticizing action of sodium alginate on starch matrix, turning this additive into a promissory alternative to replace water during melt-processing of thermoplastic corn-starch.

Reduced effects of thyroid hormone on gene expression and metamorphosis in a paedomorphic plethodontid salamander.

It has been over a century since Gudernatsch (1912, Wilhelm Roux Arch Entwickl Mech Org 35:457-483) demonstrated that mammalian thyroid gland extracts can stimulate tadpole metamorphosis. Despite the tremendous developmental diversity of amphibians, mechanisms of metamorphosis have mostly been studied in a few model systems. This limits our understanding of the processes that influence the evolution of developmental aberrations. Here we isolated thyroid hormone receptors alpha (TRα) and beta (TRß) from Oklahoma salamanders (Eurycea tynerensis), which exhibit permanently aquatic (paedomorphic) or biphasic (metamorphic) developmental modes in different populations. We found that TRα and TRß were upregulated by thyroid hormone (T3 ) in tail tissues of larvae from metamorphic populations, but basal levels of TR expression and T3 responsiveness were reduced in larvae from paedomorphic populations. Likewise, we found that T3 treatment resulted in complete loss of larval epibranchials in larvae from metamorphic populations, but little to no epibranchial remodeling occurred in larvae from paedomorphic populations over the same duration. This is the first study to directly demonstrate reduced gene expression and metamorphic responses to T3 in a paedomorphic plethodontid compared to metamorphic conspecifics, and the first salamander system to show differential expression of thyroid hormone receptors associated with alternative developmental patterns.

Economic insecurity and access to the social safety net among Latino farmworker families.

Farmworkers experience pervasive economic insecurity in part because of the seasonal nature of agricultural work and limited employment protections. Yet little is known about the adequacy of the social safety net in responding to farmworker needs. Using data from the 2005-2009 National Agricultural Workers Survey (N = 10,469), the current study analyzed predictors of social welfare participation among Latinos, who represent approximately 80 percent of all farmworkers. Nearly 95 percent are immigrants, although almost half of them have lived in the United States for more than 10 years. Descriptive analyses showed that, even among farmworker households whose income fell below the poverty line or that were headed by legally documented individuals, social services use was very low. Logistic regression analyses revealed that degree of social integration influenced social welfare participation, controlling for education, poverty status, family composition, and employment characteristics. Latino farmworkers who were recent immigrants (that is, in the United States for less than five years) had significantly lower odds of access to social insurance and public assistance programs relative to their U.S.-born counterparts. Low self-reported English ability significantly decreased access to most social insurance programs but not public assistance receipt. The findings indicate the need for social workers to engage in outreach efforts and policy advocacy to improve farmworkers access to social welfare.

Potassium sorbate controlled release from corn starch films.

Active starch films with glycerol and potassium sorbate were obtained by casting. Native and acetylated corn starches, as well as the mixture of them in equal proportions were used and filmogenic suspensions with pH 4.5 were also prepared. Sorbate concentration decreased during film storage due to its oxidative degradation. Active films resulted more yellow and less transparent than films without sorbate. The minimum inhibitory concentration of sorbate resulted 0.3%, regardless of the starch type and the formulation pH. The use of antimicrobial package was more effective to prevent microbial growth on food surfaces than the use of conventional methods. Additive kinetic release was neither affected by the starch type nor by the formulation pH. Sorbate diffusion process was mathematically modeled satisfactorily. Active films were able to inhibit Candida spp., Penicillium spp., S. aureus and Salmonella spp. growth. Active films extended 21% the shelf life of refrigerated cheese, regardless of the formulation pH.

Thermoplastic starch films reinforced with talc nanoparticles.

Nanocomposite films of thermoplastic corn starch (TPS) with talc particles were obtained by thermo-compression in order to study the effect of filler on structure, optical, and thermal properties. Talc increased the films rigid phase, thus their cross-sections resulted more irregular. Talc preferential orientation within matrix and good compatibility between particles and TPS was observed by SEM. Slight crystalline structure changes in TPS matrix were measured by XRD and DSC, due to talc nucleating effect. Randomly dispersed talc nanoagglomerates and individual platelets were assessed by TEM. Laminar morphology and nano-sized particles allowed that nanocomposite films were optically transparent. TPS-talc films resulted heterogeneous materials, presenting domains rich in glycerol and others rich in starch. Talc incorporation higher than 3%, w/w increased softening resistance of the nanocomposites as stated by DMA. Relaxation temperatures of glycerol-rich phase shifted to higher values since talc reduces the mobility of starch chains.

Starch films from a novel (Pachyrhizus ahipa) and conventional sources: Development and characterization.

Biodegradable films from ahipa, cassava and corn native starches were developed by casting method and their physicochemical, mechanical and barrier properties were analyzed taking into account the different starch botanical sources. Filmogenic suspensions were prepared; their rheological behaviors were studied and all of them exhibited film-forming ability. However, mechanical assays demonstrated that unplasticized films were too rigid, limiting their technological applications. Thus, 1.5% w/w of glycerol as plasticizer was added to filmogenic suspensions and film flexibility and extensibility were improved, this effect was more significant for ahipa and cassava starch films. Furthermore, thickness, moisture content and water solubility of the developed films were increased when plasticizer was incorporated. Glycerol addition reduced film water vapor permeability and the lowest reduction corresponded to cassava starch films due to the high viscosity of its filmogenic suspensions. Plasticized starch films resulted to be UV radiation barriers; ahipa starch films had the lowest light absorption capacity and higher transparency than cassava and corn starch films. Dynamic-mechanical analysis indicated that plasticized films were partially miscible systems exhibiting two relaxations, one attributed to the starch-rich phase and the other to the glycerol-rich one. Likewise, it could be demonstrated that glycerol exerted a major plasticizing effect on ahipa starch matrixes.

Lupus anticoagulant syndrome: a case report.

Thromboses of the deep veins (DVT) and potential complications are disorders with which physicians need to be well familiarized so they can be recognized and managed. Hypercoagulable states play a significant role in the development of DVT and these disorders must be suspect when thrombosis occurs, especially in the upper extremities. Antiphospholipid antibody syndrome (APS) is one such hypercoagulable state in which autoantibodies are formed against anionic phospholipid complexes. In vivo, these antibodies cause a hypercoagulable state through a number of proposed mechanisms, whereas in vitro they interfere with the assembly of phospholipid complexes, thereby inhibiting coagulation and prolonging various clotting times. Though appearing to be anticoagulated on ancillary testing, patients with APS are actually in a pro-thrombotic state requiring treatment with the anticoagulants heparin and warfarin. This case discussion focuses on the recognition and treatment of thrombotic events in the setting of APS.

Film forming capacity of chemically modified corn starches.

Native starch can be chemically modified to improve its functionality and to expand its uses. Modified starches were characterized and the rheological behavior of filmogenic suspensions was analyzed. The film forming capacity of different chemical modified corn starches was evaluated. Acetylated starch was selected by the characteristics of the resulted films; its optimum concentration was 5% w/w since their films exhibited the lowest water vapor permeability (WVP, 1.26×10(-10)g/msPa). The effect of glycerol as plasticizer on film properties depend on its concentration, being 1.5% w/w those that allows to obtain the lowest WVP value (1.64×10(-11)g/msPa), low film solubility in water and a more compact structure than those of unplasticized films. Mechanical behavior of plasticized acetylated starch films depends on glycerol concentration, being rigid and brittle the unplasticized ones, ductile those containing 1.5% w/w of glycerol and very flexible those with a higher plasticizer content.

A report of two deaths from massive ibuprofen ingestion.

INTRODUCTION: Ibuprofen is a commonly used non-steroidal anti-inflammatory drug. While the vast majority of exposures to the drug do not result in significant morbidity, we are reporting 2 fatalities that resulted from massive ibuprofen ingestion. CASE 1: A 17-year-old girl presented to the emergency department (ED) following an ibuprofen overdose; she was unresponsive with a metabolic acidosis and hypothermic. Her serum ibuprofen concentration was 352 microg/mL: the therapeutic range is 10-50 microg/mL. Despite intensive supportive care and continuous veno-venous hemofiltration, she expired. CASE 2: A 49-year-old man presents to the ED with a history of divalproex sodium and ibuprofen ingestion. He was unresponsive, hypotensive, and had a significant metabolic acidosis. His serum ibuprofen concentration was 260 microg/mL and serum valproate concentration was 560 microg/mL: the therapeutic range is 50-100 microg/mL. In spite of supportive care and hemodialysis, he expired. DISCUSSION: We will describe 2 cases of ibuprofen overdose characterized by cardiovascular collapse, acidosis, and hypothermia despite the use of vasopressors and renal replacement therapy. Although rarely reported, massive ibuprofen overdose may result in refractory multisystem organ failure and death.