Selective enrichment of milk fat globules using functionalized polyvinylidene fluoride membrane.

We report on the development of a functionalized membrane-based technology for selective enrichment of milk fat globules from raw bovine milk. Functionalization was conducted by in situ polymerization of acrylic acid within a polyvinylidene fluoride membrane, followed by the electrostatic attachment of a cationic polymer to impart a net positive charge. The functionalized membrane-based technology enabled a one-step method of selective separation of globules directly from milk-based on size and charge. The presence of globules in the eluate was confirmed by fluorescence microscopy. Quantification of the extracted phospholipids from globules in the eluant revealed a significantly higher amount of polar lipids than the permeate. Our study describes a comprehensive analysis of selective enrichment of fat globules using a functionalized membrane and demonstrates the beneficial effect of extracted phospholipids from enriched fat globules.

Reversibly Attached Phospholipid Bilayer-Functionalized Membrane Pores.

We report the development of reversibly attached phospholipid bilayer (PLB)-functionalized membrane pores that enabled reusability of the membrane matrix as well as the phospholipid. The functionalized architecture was constructed based on electrostatic interactions, which facilitate the reversible attachment-detachment sequence of the functional moieties within membrane pores. To demonstrate potential application, an enzyme, glucose oxidase (GOx), was electrostatically immobilized within the PLB-functionalized membrane and enzymatic catalysis was conducted under the convective flow mode. The GOx-immobilized membrane demonstrated satisfactory activity and stability. Convective flow of the substrate solution resulted in significantly higher activity than diffusive flow. Then, the enzyme was detached keeping the functional PLB backbone intact. Detachment of the enzyme without affecting the functional activity of PLB backbone permits attachment of fresh enzyme. In addition, reusability of the phospholipids is also of great importance as they have wide range of applications, but their usage is limited by higher cost. We have demonstrated the detachment of the PLB from the membrane using a simple technique. Characterization of the detached phospholipid confirmed retention of the original structural and functional properties as exhibited before attachment. To the best of our knowledge, this is the first study on reversible PLB formation within membrane pores and demonstration of a detachment technique, while maintaining the structural and functional properties of the phospholipid.

Reactive nanostructured membranes for water purification.

Many current treatments for the reclamation of contaminated water sources are chemical-intensive, energy-intensive, and/or require posttreatment due to unwanted by-product formation. We demonstrate that through the integration of nanostructured materials, enzymatic catalysis, and iron-catalyzed free radical reactions within pore-functionalized synthetic membrane platforms, we are able to conduct environmentally important oxidative reactions for toxic organic degradation and detoxification from water without the addition of expensive or harmful chemicals. In contrast to conventional, passive membrane technologies, our approach utilizes two independently controlled, nanostructured membranes in a stacked configuration for the generation of the necessary oxidants. These include biocatalytic and organic/inorganic (polymer/iron) nanocomposite membranes. The bioactive (top) membrane contains an electrostatically immobilized enzyme for the catalytic production of one of the main reactants, hydrogen peroxide (H(2)O(2)), from glucose. The bottom membrane contains either immobilized iron ions or ferrihydrite/iron oxide nanoparticles for the decomposition of hydrogen peroxide to form powerful free radical oxidants. By permeating (at low pressure) a solution containing a model organic contaminant, such as trichlorophenol, with glucose in oxygen-saturated water through the membrane stack, significant contaminant degradation was realized. To illustrate the effectiveness of this membrane platform in real-world applications, membrane-immobilized ferrihydrite/iron oxide nanoparticles were reacted with hydrogen peroxide to form free radicals for the degradation of a chlorinated organic contaminant in actual groundwater. Although we establish the development of these nanostructured materials for environmental applications, the practical and methodological advances demonstrated here permit the extension of their use to applications including disinfection and/or virus inactivation.

Effect of extracellular matrices on production and potency of mesenchymal stem cell-derived exosomes.

Mesenchymal stem cell (MSC) derived exosomes have emerged as potential acellular therapeutics for various tissue regenerative applications. However, successful clinical translation of exosome-based therapy is limited by lack of a structured production platform. Thus, in this study, the effect of decellularized extracellular matrix (dECM) was assessed on the production and potency of exosomes secreted by bone marrow-derived human MSCs. The results indicate that there was a ∼2-fold increase in MSC-exosome production when MSCs were cultured on dECM compared to TCP. Further, our study revealed that dECM generation induced by ascorbic acid (AA) up to 100 µg mL-1 highly increased exosome yield thereby indicating a potential scale up method for MSC exosome production. The bioactivity of exosomes was investigated by their ability to improve the healing of wounded human skin explants. Wound closure was enhanced in the presence of exosomes isolated from MSCs cultured on ascorbic acid-induced dECM compared to TCP generated MSC-exosomes. In summary, this study suggests a promising solution to a major bottleneck in large-scale production of MSC exosomes for cell-free therapy.

In Situ Synthesis of Silver Nanoparticles within Hydrogel-Conjugated Membrane for Enhanced Antibacterial Properties.

Biofouling negatively impacts water treatment performance of membranes by reducing water permeability, increasing energy consumption, and shortening the lifetime of the membranes. In this study, we integrated the bactericidal property of silver nanoparticles (AgNPs) with hydrophilicity of hydrogels to modify membranes that not only reduce adhesion, but also deactivate the adhered bacteria. Two approaches for AgNP synthesis were adopted-in situ synthesis and encapsulation in single step, and immobilization in multistep. Formation of AgNPs was confirmed by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD) studies. Compared to the pristine membrane, AgNP/hydrogel-modified membranes displayed no adverse effect in water flux under gravitational flow condition. The AgNP/hydrogel-modified membranes also exhibited better antibacterial properties (inhibition of adhesion and growth of Escherichia coli) as demonstrated by the bacterial growth, inhibition zone, and coculture (with the membranes) studies. The improvements could be attributed to the synergistic effect of hydrophilic hydrogel networks and the presence of bactericidal AgNPs. In addition, comparison of the antibacterial studies revealed the superiority of the encapsulated AgNPs over the immobilized AgNPs. This could be attributed to the efficient release of the former over the latter. To the best of our knowledge, this is the first study that demonstrates the enhancement of antibacterial properties of membrane via in situ synthesis and encapsulation of AgNPs within hydrogel matrices.

A risk-based decision support framework for selection of appropriate safety measure system for underground coal mines.

In the context of underground coal mining industry, the increased economic issues regarding implementation of additional safety measure systems, along with growing public awareness to ensure high level of workers safety, have put great pressure on the managers towards finding the best solution to ensure safe as well as economically viable alternative selection. Risk-based decision support system plays an important role in finding such solutions amongst candidate alternatives with respect to multiple decision criteria. Therefore, in this paper, a unified risk-based decision-making methodology has been proposed for selecting an appropriate safety measure system in relation to an underground coal mining industry with respect to multiple risk criteria such as financial risk, operating risk, and maintenance risk. The proposed methodology uses interval-valued fuzzy set theory for modelling vagueness and subjectivity in the estimates of fuzzy risk ratings for making appropriate decision. The methodology is based on the aggregative fuzzy risk analysis and multi-criteria decision making. The selection decisions are made within the context of understanding the total integrated risk that is likely to incur while adapting the particular safety system alternative. Effectiveness of the proposed methodology has been validated through a real-time case study. The result in the context of final priority ranking is seemed fairly consistent.

Analysis of occupational health hazards and associated risks in fuzzy environment: a case research in an Indian underground coal mine.

This paper presents a unique hierarchical structure on various occupational health hazards including physical, chemical, biological, ergonomic and psychosocial hazards, and associated adverse consequences in relation to an underground coal mine. The study proposes a systematic health hazard risk assessment methodology for estimating extent of hazard risk using three important measuring parameters: consequence of exposure, period of exposure and probability of exposure. An improved decision making method using fuzzy set theory has been attempted herein for converting linguistic data into numeric risk ratings. The concept of 'centre of area' method for generalized triangular fuzzy numbers has been explored to quantify the 'degree of hazard risk' in terms of crisp ratings. Finally, a logical framework for categorizing health hazards into different risk levels has been constructed on the basis of distinguished ranges of evaluated risk ratings (crisp). Subsequently, an action requirement plan has been suggested, which could provide guideline to the managers for successfully managing health hazard risks in the context of underground coal mining exercise.

In Silico Designing of an Industrially Sustainable Carbonic Anhydrase Using Molecular Dynamics Simulation.

Carbonic anhydrase (CA) is a family of metalloenzymes that has the potential to sequestrate carbon dioxide (CO2) from the environment and reduce pollution. The goal of this study is to apply protein engineering to develop a modified CA enzyme that has both higher stability and activity and hence could be used for industrial purposes. In the current study, we have developed an in silico method to understand the molecular basis behind the stability of CA. We have performed comparative molecular dynamics simulation of two homologous α-CA, one of thermophilic origin (Sulfurihydrogenibium sp.) and its mesophilic counterpart (Neisseria gonorrhoeae), for 100 ns each at 300, 350, 400, and 500 K. Comparing the trajectories of two proteins using different stability-determining factors, we have designed a highly thermostable version of mesophilic α-CA by introducing three mutations (S44R, S139E, and K168R). The designed mutant α-CA maintains conformational stability at high temperatures. This study shows the potential to develop industrially stable variants of enzymes while maintaining high activity.

smRithm: Graphical user interface for heart rate variability analysis.

Over the past 25 years, Heart rate variability (HRV) has become a non-invasive research and clinical tool for indirectly carrying out investigation of both cardiac and autonomic system function in both healthy and diseased. It provides valuable information about a wide range of cardiovascular disorders, pulmonary diseases, neurological diseases, etc. Its primary purpose is to access the functioning of the nervous system. The source of information for HRV analysis is the continuous beat to beat measurement of inter-beat intervals. The electrocardiography (ECG or EKG) is considered as the best way to measure inter-beat intervals. This paper proposes an open source Graphical User Interface (GUI): smRithm developed in MATLAB for HRV analysis that will apply effective techniques on the raw ECG signals to process and decompose it in a simpler manner to obtain more useful information out of signals that can be utilized for more powerful and efficient applications in the near future related to HRV.

Removal of enzymatic and fermentation inhibitory compounds from biomass slurries for enhanced biorefinery process efficiencies.

Within the biorefinery paradigm, many non-monomeric sugar compounds have been shown to be inhibitory to enzymes and microbial organisms that are used for hydrolysis and fermentation. Here, two novel separation technologies, polyelectrolyte polymer adsorption and resin-wafer electrodeionization (RW-EDI), have been evaluated to detoxify a dilute acid pretreated biomass slurry. Results showed that detoxification of a dilute acid pretreated ponderosa pine slurry by sequential polyelectrolyte and RW-EDI treatments was very promising, with significant removal of acetic acid, 5-hydroxymethyl furfural, and furfural (up to 77%, 60%, and 74% removed, respectively) along with >97% removal of sulfuric acid. Removal of these compounds increased the cellulose conversion to 94% and elevated the hydrolysis rate to 0.69 g glucose/L/h. When using Saccharomyces cerevisiae D(5)A for fermentation of detoxified slurry, the process achieved 99% of the maximum theoretical ethanol yield and an ethanol production rate nearly five-times faster than untreated slurry.

An attempt towards simultaneous biobased solvent based extraction of proteins and enzymatic saccharification of cellulosic materials from distiller's grains and solubles.

Distiller's grains and solubles (DGS) is the major co-product of corn dry mill ethanol production, and is composed of 30% protein and 30-40% polysaccharides. We report a strategy for simultaneous extraction of protein with food-grade biobased solvents (ethyl lactate, d-limonene, and distilled methyl esters) and enzymatic saccharification of glucan in DGS. This approach would produce a high-value animal feed while simultaneously producing additional sugars for ethanol production. Preliminary experiments on protein extraction resulted in recovery of 15-45% of the protein, with hydrophobic biobased solvents obtaining the best results. The integrated hydrolysis and extraction experiments showed that biobased solvent addition did not inhibit hydrolysis of the cellulose. However, only 25-33% of the total protein was extracted from DGS, and the extracted protein largely resided in the aqueous phase, not the solvent phase. We hypothesize that the hydrophobic solvent could not access the proteins surrounded by the aqueous phase inside the fibrous structure of DGS due to poor mass transfer. Further process improvements are needed to overcome this obstacle.

Functionalized Membranes by Layer-By-Layer Assembly of Polyelectrolytes and In Situ Polymerization of Acrylic Acid for Applications in Enzymatic Catalysis.

This research work was directed toward the development of highly active, stable, and reusable functionalized polymeric membrane domains for enzymatic catalysis. Functionalized membranes were created by two different approaches. In the first approach, which involved alternative attachment of cationic and anionic polyelectrolytes, functionalization was performed using a layer-by-layer (LBL) assembly technique within a nylon-based microfiltration (MF) membrane. In the second approach, a hydrophobic polyvinylidene fluoride (PVDF) MF membrane was functionalized by the in situ polymerization of acrylic acid. The enzyme, glucose oxidase (GOX), was then electrostatically immobilized inside the functionalized membrane domains to study the catalytic oxidation of glucose to gluconic acid and H2O2. Characterization of the functionalized membranes, in terms of polyelectrolyte/polymer domains and permeate flux, was also conducted. The kinetics of H2O2 formation was discussed, along with the effects of residence time and pH on the activity of GOX. The stability and reusability of the electrostatically immobilized enzymatic system were also investigated.