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Layered double hydroxides (LDH) exhibit macromolecular behavior due to their layered structure, providing unique properties that make them suitable for various applications. Their crystal structure allows for intercalation of various species, demonstrating excellent thermal stability and mechanical strength. Synthesis methods, such as co-precipitation, ion exchange, and hydrothermal techniques, enable the preparation of well-defined LDH macromolecules with tailored characteristics. These materials find applications in catalysis, drug delivery systems, environmental remediation processes, and energy storage devices. Our research described here an LDH material based on nickel, copper, and aluminum was synthesized, characterized and used as a catalyst for the oxidation of Acetaminophen (Ac) using H2O2. Our materials were created using the co-precipitation process at a constant pH. Fourier Transform infrared spectroscopy (FTIR), Raman spectroscopy (RAMAN), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Energy-Dispersive X-ray Spectroscopy (EDS) were used to characterize the synthesized material. The material was crystalline and devoid of contaminants, according to the characterization. The CuNiAl-CO3 material was used to catalyze the elimination of the Ac (1 g.L−1) from an aqueous solution. The amount of the LDH, the molar ratio (oxidant/pollutant), the temperature, and the pH were among the experimental factors that were modified to get superior results. The kinetic analysis revealed that using 3 g L−1 of LDH with a molar ratio (oxidant/pollutant) of 2.5 for 3 h at room temperature and without modification of the pH of the solution resulted in a complete degradation of the Ac, and that our LDH performed best in acidic conditions. [ABSTRACT FROM AUTHOR]

Background and Hypothesis The glymphatic system (GS), a brain waste clearance pathway, is disrupted in various neurodegenerative and vascular diseases. As schizophrenia shares clinical characteristics with these conditions, we hypothesized GS disruptions in patients with schizophrenia spectrum disorder (SCZ-SD), reflected in increased brain macromolecule (MM) and decreased diffusion-tensor-image-analysis along the perivascular space (DTI-ALPS) index. Study Design Forty-seven healthy controls (HCs) and 103 patients with SCZ-SD were studied. Data included 135 proton magnetic resonance spectroscopy (1H-MRS) sets, 96 DTI sets, with 79 participants contributing both. MM levels were quantified in the dorsal-anterior cingulate cortex (dACC), dorsolateral prefrontal cortex, and dorsal caudate (point resolved spectroscopy, echo-time = 35ms). Diffusivities in the projection and association fibers near the lateral ventricle were measured to calculate DTI-ALPS indices. General linear models were performed, adjusting for age, sex, and smoking. Correlation analyses examined relationships with age, illness duration, and symptoms severity. Study Results MM levels were not different between patients and HCs. However, left, right, and bilateral DTI-ALPS indices were lower in patients compared with HCs (P  < .001). In HCs, age was positively correlated with dACC MM and negatively correlated with left, right, and bilateral DTI-ALPS indices (P  < .001). In patients, illness duration was positively correlated with dACC MM and negatively correlated with the right DTI-ALPS index (P  < .05). In the entire population, dACC MM and DTI-ALPS indices showed an inverse correlation (P  < .01). Conclusions Our results suggest potential disruptions in the GS of patients with SCZ-SD. Improving brain's waste clearance may offer a potential therapeutic approach for patients with SCZ-SD. [ABSTRACT FROM AUTHOR]

We present a model of the growth rate and elemental stoichiometry of phytoplankton as a function of resource allocation between and within broad macromolecular pools under a variety of resource supply conditions. The model is based on four, empirically-supported, cornerstone assumptions: that there is a saturating relationship between light and photosynthesis, a linear relationship between RNA/protein and growth rate, a linear relationship between biosynthetic proteins and growth rate, and a constant macromolecular composition of the light-harvesting machinery. We combine these assumptions with statements of conservation of carbon, nitrogen, phosphorus, and energy. The model can be solved algebraically for steady state conditions and constrained with data on elemental stoichiometry from published laboratory chemostat studies. It interprets the relationships between macromolecular and elemental stoichiometry and also provides quantitative predictions of the maximum growth rate at given light intensity and nutrient supply rates. Themodel is compatible with data sets from several laboratory studies characterizing both prokaryotic and eukaryotic phytoplankton from marine and freshwater environments. It is conceptually simple, yet mechanistic and quantitative. Here, the model is constrained only by elemental stoichiometry, but makes predictions about allocation to measurable macromolecular pools, which could be tested in the laboratory. [ABSTRACT FROM AUTHOR]

Melanins are macromolecular pigments widely spread in many living organisms, with unique physical and chemical properties. Specifically, their conductive properties have drawn attention for applications in different devices; however, the electrochemical response is equally necessary for designing technologies in sustainable bioelectronics. In this sense, we report a comparative study of the redox electrochemical properties of non‐functionalized and sulfonated melanins in different pH environments. The electrochemical response was investigated using cyclic voltammetry, electrochemical impedance spectroscopy, dielectric permittivity and AC/DC conductivity at pH 3, 5 and 7. The voltammetric currents were higher at low pH, in agreement with the known proton transport properties of melanins. The effect of pH on electrochemical properties was slightly more significant in non‐functionalized pigments. Melanins with a higher 5,6‐dihydroxyindole carboxylic acid/5,6‐dihydroxyindole ratio showed high DC current and low impedance. No significant difference was observed in the dielectric relaxation process between the different samples. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Protein–polysaccharide–tannin interactions are important in every aspect of red wine production from physical stability to color, astringency, and body. For this model study, bovine serum albumin (BSA) was selected as the protein, while carboxymethyl cellulose (CMC), mannoproteins, and pectin were the model polysaccharides. Each protein–polysaccharide combination was analyzed for zeta (ζ) potential and particle size at neutral pH and within the wine‐like solution. Mixtures were assessed regarding their protective, affinitive, and aggregative behaviors. Based on their individual ζ‐potentials, pectin and mannoprotein were most stable at lower concentrations. At higher concentrations, they reduced the suspension's stability and increased the aggregate sizes. CMC consistently increased the stability of any solution under neutral pH conditions. However, with increasing concentrations, these large aggregates are expected to precipitate. Fruit pectin (FP) and BSA interactions seemed to be the main factors in the formation of visible precipitates at neutral pH. FP and the mannoprotein decreased stability enough to cause precipitation without haze formation. The mannoprotein decreased particle sizes, in both the suspension and precipitation, which may indicate greater selectivity toward proteins. FP also decreased the suspended particle sizes under wine conditions. These findings demonstrate the use of ζ‐potential and particle size values to characterize macromolecular interactions in model systems and can also be used to indicate effective fining agents. Practical Application: This work demonstrates the capabilities of ζ‐potential analysis paired with size particle measurements to predict and characterize the interactions between macromolecules in complex systems. The interactions between model wine macromolecules can be evaluated with this technology at a level that cannot be reached with any other analytical technique. [ABSTRACT FROM AUTHOR]

The present study synthesized a novel dendrimer with specific functional groups and use them as pharmaceutical carriers at the nanoscale. First, a glycodendrimer was synthesized and a porphyrin substance was selected as its core. Afterward, this substance was subsequently reacted with gallic acid and bromo valerate step-by-step and it was conjugated with acrylonitrile functionalized with Tris (hydroxymethyl) aminomethane. Eventually, the composition was reacted with Tris [α-D Manos (pyrazolyl oxy) methyl] methylamine and glycodendrimer (TTP-Tr-GD) was prepared via a divergent approach to develop drug delivery system. The nanocarrier was characterized using several techniques, such as scanning electron microscopy (FE-SEM), thermal analysis (TGA), NMR, Fourier transform infrared (FT-IR), differential laser scanning (DLS), elemental mapping (EDS), and Zeta potential. Effective factors on the release of the drug delivery, including the best time to absorb, sample pH, and reaction temperature were optimized. The statistically optimized sorption efficiency (98.11%) was attained at pH = 5.5, and a contact time of 15 min. As a result of the functional groups on the surface of the TTP-Tr-GD are appropriate for simultaneous determination and high throughput analysis of drug delivery system. [ABSTRACT FROM AUTHOR]

Inorganic nanoparticles are a critical component in a broad range of applications spanning catalysis, sensing, optics, and electronics. The nucleation and growth mechanisms involved during their synthesis are known to be crucial for controlling their final performance. Macromolecules can display sequence definition, inherent chirality, metal ion targeting moieties, and can also form self-assemblies, affording them the ability to not only stabilize but also precisely control the synthesis and organization of nanoparticles for an intended application. Herein, we report the recent trends in inorganic nanoparticle synthesis mediated by peptides, peptoids, DNA, other biopolymers, and synthetic polymers. Important design parameters and future trends are also discussed. [ABSTRACT FROM AUTHOR]

Glioblastoma multiforme (GBM) remains one of the most aggressive and treatment-resistant forms of brain cancer, with a notoriously poor prognosis. A major hurdle in effectively targeting GBM is the presence of the blood-brain barrier (BBB), a highly selective barrier that impedes the delivery of therapeutic agents to the tumor site. This review examines the potential of permeable macromolecules as a novel approach for targeted therapy in GBM treatment. We explore the design and function of these macromolecules, which are engineered to traverse the BBB and deliver therapeutic agents directly to the tumor, thereby enhancing treatment efficacy and minimizing systemic toxicity. The review highlights various types of permeable macromolecules, including their mechanisms of BBB penetration, and the strategies employed to optimize their therapeutic payload. We also address the challenges in the development and clinical translation of these macromolecules, including issues related to biocompatibility, pharmacokinetics, and targeted delivery. Additionally, we discuss the potential of these macromolecules in overcoming drug resistance and preventing tumor recurrence, key concerns in GBM treatment. This review underscores the promising future of permeable macromolecules in GBM therapy, offering insights into their role in advancing personalized and targeted treatment strategies. With continued research and development, these macromolecules hold the potential to significantly improve outcomes for patients suffering from this devastating disease. [ABSTRACT FROM AUTHOR]

A simple two-stage extraction and recovery method for macromolecules from microalgae biomass, termed CASS (concentrating the microalgae solution, acid pretreatment, high-shear-assisted lipid extraction, and separation), was developed. This method effectively processed the wet biomass of Chlorella sp. ABC-001 at a moderately low biomass concentration (50 g/L). The optimal conditions were acid pretreatment with 5 wt.% H2SO4 at 100 °C for 1 h, followed by high-shear extraction using hexane at 3000 rpm for 30 min. The acid pretreatment hydrolyzed carbohydrates and phospholipids, disrupting the cell wall and membrane, while high-shear mixing enhanced mass transfer rates between solvents and lipids, overcoming the hydraulic barrier at the cell surface. Within 10 min after completing the process, the extraction mixture achieved natural phase separation into water, solvent, and biomass residue layers, each enriched with carbohydrates, lipids, and proteins, respectively. The CASS process demonstrated high esterifiable lipid yields (91%), along with substantial recovery of glucose (90%) and proteins (100%). The stable phase separation prevented emulsion formation, simplifying downstream processing. This study presents the results on cell disruption, optimal acid treatment concentration, and high-shear mixing to achieve macromolecule separation, expanding the lipid-centric microalgal process to a comprehensive biorefinery concept. [ABSTRACT FROM AUTHOR]

In oxygen (O2)‐dependent photodynamic therapy (PDT), photosensitizers absorb light energy, which is then transferred to ambient O2 and subsequently generates cytotoxic singlet oxygen (1O2). Therefore, the availability of O2 and the utilization efficiency of generated 1O2 are two significant factors that influence the effectiveness of PDT. However, tumor microenvironments (TMEs) characterized by hypoxia and limited utilization efficiency of 1O2 resulting from its short half‐life and short diffusion distance significantly restrict the applicability of PDT for hypoxic tumors. To address these challenges, numerous macromolecular nano‐assemblies (MNAs) have been designed to relieve hypoxia, utilize hypoxia or enhance the utilization efficiency of 1O2. Herein, we provide a comprehensive review on recent advancements achieved with MNAs in enhancing the effectiveness of O2‐dependent PDT against hypoxic tumors. [ABSTRACT FROM AUTHOR]

Reinforcement learning (RL) is one important branch of artificial intelligence (AI), which intuitively imitates the learning style of human beings. It is commonly derived from solving game playing problems and is extensively used for decision‐making, control and optimization problems. It has been extensively applied for solving complicated problems with the property of Markov decision‐making processes. With data accumulation and comprehensive analysis, researchers are not only satisfied with predicting the results for experimental systems but also hope to design or control them for the sake of obtaining the desired properties or functions. RL is potentially facilitated to solve a large number of complicated biological and chemical problems, because they could be decomposed into multi‐step decision‐making process. In practice, substantial progress has been made in the application of RL to the field of biomedicine. In this paper, we will first give a brief description about RL, including its definition, basic theory and different type of methods. Then we will review some detailed applications in various domains, for example, molecular design, reaction planning, molecular simulation and etc. In the end, we will summarize the essentialities of RL approaches to solve more diverse problems compared with other machine learning methods and also outlook the possible trends to overcome their limitations in the future. This article is categorized under:Data Science > ChemoinformaticsData Science > Computer Algorithms and ProgrammingData Science > Artificial Intelligence/Machine Learning [ABSTRACT FROM AUTHOR]

The document is a corrigendum for an article titled "A mechanistic model of macromolecular allocation, elemental stoichiometry, and growth rate in phytoplankton." The authors identified mistakes in the values in Table 1 related to elemental ratio values for protein, RNA, and DNA. They provided corrected values and reoptimized parameters, which yielded nearly identical results to the original version. The authors clarified that these corrections do not alter the scientific conclusions of the article. [Extracted from the article]

Measurement of molecular weight is an integral part of macromolecular and polymer characterization which usually has limitations. Herein, this article presents the use of a bench‐top 80 MHz Nuclear Magnetic Resonance (NMR) spectrometer for diffusion‐ordered spectroscopy as a practical and rapid approach for the determination of molecular weight/size using a novel solvent and polymer‐independent universal calibration. [ABSTRACT FROM AUTHOR]

Natural cellulose owing to its remarkable microstructural and physiochemical behaviour, and its eco-friendliness have attracted significant interest among the researchers. Therefore, in this work, microcrystalline cellulose (MCC) is extracted from the Musa paradisiaca plant leaf (MPPL) debris which is accumulated in large quantity and treated as waste material. The purified micro-cellulose is obtained by subjecting the MPPL raw material to alkali treatment followed by acid hydrolysis, bleaching and slow pyrolysis. From the FT-IR spectra of the cleaned cellulose, it is observed that its amorphous phase is eliminated. The crystallinity index is found to be 87.42% and this value is attributed to the sodium chlorite bleaching. The particle size analyzer results show that the micro-cellulose found to have a bimodal distribution with an average size of 35.97 μm and standard deviation 16.53. It is evident from SEM that the microcrystalline cellulose is of semi-spherical in shape and found to be aggregated with uneven distribution. Further, TGA analysis is carried out in this work and the results show that the microcrystalline cellulose can exhibit high heat resistance up to 297 °C. Surface roughness values (Ra) for MPPL MCC is 58.41 μm. The properties are well suited for futuristic polymer composite applications such as filler addition in biofilm for packaging industries and coating material in pharma industries. [ABSTRACT FROM AUTHOR]

Digestive enzymes can selectively degrade proteins, carbohydrates and lipids; and their supplementation alongside food may accelerate the breakdown of complex food matrices, facilitate greater nutrient absorption, decrease food sensitivities and aid in the management of certain disease states. Several intrinsic and extrinsic factors govern food digestion and for every individual this phenomenon is unique. This study was conducted as a randomized, crossover, placebo-controlled design where each participant served as their own control. This post-hoc analysis investigated the impact of a dietary enzyme supplementation blend known as Elevase® on dietary macromolecule digestion in samples from otherwise healthy participants that had previously undergone a small bowel resection, resulting in an ileostomy (NCT04489810). This is the first time this study-paradigm has been used for the assessment of in vivo dietary breakdown following enzyme supplementation. Arguably, this technique offers superior data when compared to that generated in artificial gut digestion models, preclinical animal models, or indeed conventional clinical studies using stool analyses, as it allows real-time access to samples in situ in the small intestine where the majority of nutritional absorption takes place. It was demonstrated that after 4 h, Elevase® significantly increased monosaccharide levels (predominantly glucose and fructose) in the ileostomy samples taken from the same individuals on the same diet on a different day. In addition, the bile salt taurohyodeoxycholic acid was also increased, suggesting a physiological host response to the macromolecule digestion induced by the enzymatic blend. Overall, these findings suggest Elevase® could accelerate food digestion and potentially increase nutrient availability from the diet.

Alzheimer's disease (AD) is a prevalent neurodegenerative disorder characterized by progressive neuronal damage and cognitive decline. Recent studies have shed light on the involvement of not only the blood-brain barrier (BBB) dysfunction but also significant alterations in cellular junctions in AD pathogenesis. In this review article, we explore the role of the BBB and cellular junctions in AD pathology, with a specific focus on the hippocampus. The BBB acts as a crucial protective barrier between the bloodstream and the brain, maintaining brain homeostasis and regulating molecular transport. Preservation of BBB integrity relies on various junctions, including gap junctions formed by connexins, tight junctions composed of proteins such as claudins, occludin, and ZO-1, as well as adherence junctions involving molecules like vascular endothelial (VE) cadherin, Nectins, and Nectin-like molecules (Necls). Abnormalities in these junctions and junctional components contribute to impaired neuronal signaling and increased cerebrovascular permeability, which are closely associated with AD advancement. By elucidating the underlying molecular mechanisms governing BBB and cellular junction dysfunctions within the context of AD, this review offers valuable insights into the pathogenesis of AD and identifies potential therapeutic targets for intervention. [ABSTRACT FROM AUTHOR]

In this article we present the results of time-of-flight mass spectrometry of volatile products formed during the electrical breakdown of polyethylene terephthalate and polypropylene polymer films in high vacuum. During the breakdown of films, all the substance emitted from the breakdown channel is a gas of low-molecular products of destruction of macromolecules. The breakdown mass spectra do not contain lines of carbon molecules, the presence of which could indicate carbonation of the channel. To explain the formation of charge carriers, the ionization mechanism of destruction of macromolecules in an electric field is used without the involvement of impact ionization. The final stage of electrical breakdown (the flow of a high-density conduction current) occurs when the critical concentration of traps and electrons ≈1024 m–3 is reached. [ABSTRACT FROM AUTHOR]

Starch is a biological macromolecule with myriad of industrial uses. The growing need for starch and native starch deficiencies have necessitated researches into under-exploited starch sources and modifications, respectively. Chrysophyllum albidum (African star apple, ASA) seed is a waste consisting of 63.94% carbohydrate in its kernel. Its starch content can be fully utilised, industrially, if it is in a suitable form and its properties understood. That necessitated the isolation of ASA kernel starch, its modification and properties assessment. Acetylation, acid-thinning and oxidation were performed on the native Chrysophyllum albidum kernel starch, NACA, to produce the acetylated Chrysophyllum albidum kernel starch, ACCA, acid-thinned Chrysophyllum albidum kernel starch, ATCA, and oxidised Chrysophyllum albidum kernel starch, OXCA, respectively. The physicochemical properties of the native and modified starches were investigated with established methods. The yield of starch was 43.76%. The acetylated and oxidised starches had low degrees of substitution. FTIR results confirmed the introduction of carbonyl functionality into the acetylated and oxidised starches. Starch morphology revealed smooth, small rounded and truncated ellipsoid granules with diameter ranges of 7–20 μm. Swelling power of modified starches improved, except for the acid-thinned, and increased with temperature. Acetylated and oxidised starches had significantly (p < 0.05) higher water and oil absorption capacities, respectively. Acid-thinning significantly improved starch pasting properties and reduced retrogradation tendency. Modification improved the gelatinisation transition temperature of native starch. [ABSTRACT FROM AUTHOR]

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Simple Summary: Many cancer therapeutics may have a robust effect on target molecules but lack the means of effective localization into tumor cells, thus displaying reduced therapeutic efficacy. Viruses bear naturally evolved machinery to ensure entry and localization of nucleic acid cargo into a cell. Utilizing and better understanding the mechanism of the penton base protein that contributes to the adenovirus cell entry machinery may improve the intracellular delivery of tumor targeting therapeutics. This review describes the progression of penton-base-derived cancer nanotherapeutic development and highlights essential requirements for robust delivery into a tumor cell. Macromolecular therapeutics such as nucleic acids, peptides, and proteins have the potential to overcome treatment barriers for cancer. For example, nucleic acid or peptide biologics may offer an alternative strategy for attacking otherwise undruggable therapeutic targets such as transcription factors and similar oncologic drivers. Delivery of biological therapeutics into tumor cells requires a robust system of cell penetration to access therapeutic targets within the cell interior. A highly effective means of accomplishing this may be borrowed from cell-penetrating pathogens such as viruses. In particular, the cell entry function of the adenovirus penton base capsid protein has been effective at penetrating tumor cells for the intracellular deposition of macromolecular therapies and membrane-impermeable drugs. Here, we provide an overview describing the evolution of tumor-targeted penton-base-derived nano-capsids as a framework for discussing the requirements for overcoming key barriers to macromolecular delivery. The development and pre-clinical testing of these proteins for therapeutic delivery has begun to also uncover the elusive mechanism underlying the membrane-penetrating function of the penton base. An understanding of this mechanism may unlock the potential for macromolecular therapeutics to be effectively delivered into cancer cells and to provide a treatment option for tumors resisting current clinical therapies. [ABSTRACT FROM AUTHOR]

Due to the high solubility in water and the structural compatibility of polyethylene glycol with water molecules, it is a good model system for studying the mechanisms of interaction between water and biopolymers. The behavior of biopolymers in living organisms strongly depends on the hydration of macromolecules in the aquatic environment. In this work the effective hydration numbers of polyethylene glycols are determined using a new viscosity model developed for electrolytes and experimental data on the viscosity of dilute aqueous solutions of polyethylene glycols (300–35000). The calculated hydration numbers are in good agreement with the literature data and increase with increasing molecular mass of polyethylene glycol: as the molecular mass increases, starting from a molecular mass of 1000, the chain begins to fold in on itself, forming segment‐segment interactions, trapping additional, more loosely bound water between the segments. Based on the dependence of the intrinsic viscosity on the molecular mass according to the Mark‐Houwink equation, it is shown that PEGs are the flexible polymers and highly soluble in water. [ABSTRACT FROM AUTHOR]

Biologics address a range of unmet clinical needs, but the occurrence of biologics-induced liver injury remains a major challenge. Development of cimaglermin alfa (GGF2) was terminated due to transient elevations in serum aminotransferases and total bilirubin. Tocilizumab has been reported to induce transient aminotransferase elevations, requiring frequent monitoring. To evaluate the clinical risk of biologics-induced liver injury, a novel quantitative systems toxicology modeling platform, BIOLOGXsym™, representing relevant liver biochemistry and the mechanistic effects of biologics on liver pathophysiology, was developed in conjunction with clinically relevant data from a human biomimetic liver microphysiology system. Phenotypic and mechanistic toxicity data and metabolomics analysis from the Liver Acinus Microphysiology System showed that tocilizumab and GGF2 increased high mobility group box 1, indicating hepatic injury and stress. Tocilizumab exposure was associated with increased oxidative stress and extracellular/tissue remodeling, and GGF2 decreased bile acid secretion. BIOLOGXsym simulations, leveraging the in vivo exposure predicted by physiologically-based pharmacokinetic modeling and mechanistic toxicity data from the Liver Acinus Microphysiology System, reproduced the clinically observed liver signals of tocilizumab and GGF2, demonstrating that mechanistic toxicity data from microphysiology systems can be successfully integrated into a quantitative systems toxicology model to identify liabilities of biologics-induced liver injury and provide mechanistic insights into observed liver safety signals. [ABSTRACT FROM AUTHOR]

Wool is sensitive toward the effect of alkaline solutions which are usually used in the dissolution of wool fibers to regenerate keratin. In this investigation, the effect of different alkalis on the chemical composition and the secondary structure of wool was studied. Wool was treated with equivalent amounts of alkali metal hydroxides (lithium, sodium, and potassium hydroxides) as well as alkaline earth metal hydroxides (strontium and barium hydroxides). The effect of these alkalis on wool was monitored using amino acid analysis, elemental analysis, carboxylic content, acid, and base combining capacity, urea-bisulfite and alkali solubility, and FTIR spectroscopy. Further structure elucidation was conducted by thermo-gravimetric analysis, differential scanning calorimetry, and X-ray diffraction pattern. Scanning electron microscopy was used to assign the alteration of the fiber morphology of the alkali-treated wool. The results of this investigation indicate that the effect of the used alkalis on wool is not similar. Cystine, glycine, and the basic amino acids are the most affected species in the treated wool. Some elimination reactions were involved during alkaline treatment of wool; namely decarboxylation, desulphydration, and deamination. The secondary structure of wool treated with Sr(OH)2 and Ba(OH)2 was changed from the α-helical structure into the β-sheet form.

The development status of slippery water fracturing fluid systems for reservoir transformation is reviewed, different types of friction reduction agents for slippery water fracturing are summarized, including natural polymers, powder-type synthetic polymers, emulsion-type synthetic polymers, surfactants and other types, and the four sliding water drag reduction hypotheses such as pseudoplastic, viscoelastic, effective slip and turbulence inhibition are analyzed, different types of friction equations are discussed, and the influence of polymer microstructure and rheological properties on the sand carrying properties is pointed out.There are many influencing factors, which point out the direction of the next step of mechanism research and product development. [ABSTRACT FROM AUTHOR]

Cardiac blood pool imaging is currently performed almost exclusively with 99mTc-based compounds and SPECT/CT imaging. Using a generator-based PET radioisotope has a few advantages, including not needing nuclear reactors to produce it, obtaining better resolution in humans, and potentially reducing the radiation dose to the patient. When the shortlived radioisotope 68Ga is used, it can be applied repeatedly on the same day—for example, for the detection of bleeding. Our objective was to prepare and evaluate a long-circulating polymer functionalized with gallium for its biodistribution, toxicity, and dosimetric properties. A 500 kDa hyperbranched polyglycerol was conjugated to the chelator NOTA and radiolabeled rapidly at room temperature with 68Ga. It was then injected intravenously into a rat, and gated imaging allowed us to easily observe wall motion and cardiac contractility, confirming the suitability of this radiopharmaceutical for cardiac blood pool imaging. Internal radiation dose calculations showed that the radiation doses that patients would receive from the PET agent would be 2.5× lower than those from the 99mTc agent. A complete 14-day toxicology study in rats concluded that there were no gross pathology findings, changes in body or organ weights, or histopathological events. This radioactive-metal-functionalized polymer might be a suitable non-toxic agent to advance for clinical application. [ABSTRACT FROM AUTHOR]

The article presents data on the synthesis and antimicrobial properties of guanidine-containing carboxymethylcellulose derivatives with different physical and chemical characteristics. The regularities of the reaction of nucleophilic substitution of the aldehyde groups of modified Na-carboxymethylcellulose (Na-CMC) by guanidine under different conditions have been studied. It has been found that the maximal replacement of reactive electrophilic groups by nucleophilic reagent depends on the pH value of the medium, molar ratio of guanidine, and the degree of oxidation of cellulose ester. The azomethine derivatives with different content of nitrogen-containing fragments in the polymer chain have been synthesized by varying the reaction conditions and the number of aldehyde groups in oxidized Na-CMC. Chemical reduction of labile azomethine bonds has led to water-soluble derivatives that contain strong amino-bound guanidine groups. The study shows and substantiates the influence of structural parameters (degree of substitution, quantitative guanidine content, pKα values, and nature of counterions) of macromolecular systems on antibacterial and antifungal properties. The developed approach to the synthesis opens up prospects for the creation of antimicrobial derivatives with regulated physical and chemical characteristics and specified biologically active properties. [ABSTRACT FROM AUTHOR]

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[Display omitted] • A novel macromolecular hybrid was synthesized. • Excellent flame retardancy and smoke suppression were enabled via hybrid method. • Compatibility between three thermally conductive fillers and Al-IFR was studied. • A delicate balance between fire safety and thermal conductivity was achieved. Achieving a delicate balance between fire resistance and thermal conductivity in intumescent flame-retarded polypropylene (PP) poses a formidable challenge, primarily due to the susceptibility of intumescent barrier layers to functional fillers. To address this concern, a novel hybrid macromolecule (Al-PAP) was synthesized via polycondensation reaction, showcasing promising potential in constructing flame-retardant and thermally conductive PP. Remarkably, the inclusion of mere 14 wt% of the Al-PAP/melamine polyphosphate (Al-IFR) system raised the limiting oxygen index (LOI) of PP to 28.3 %, equivalent to that of PP containing 20 wt% of the conventional system, emphasizing the superior efficacy of the hybrid Al-PAP. Further, the PP with 20 wt% Al-IFR performed a 32.2 % of LOI, 850 °C of glow wire ignition temperature, >960 °C of glow wire flammable index and UL 94 V-0 ratings (3.2 mm & 1.6 mm), indicating the high flame retardancy. Subsequently, three thermal conductive fillers – aluminum oxide, boron nitride, and multi-walled carbon nanotubes – were evaluated based on a 20 wt% dosage of Al-IFR. Alumina emerged as the optimal candidate, enhancing flame retardancy and smoke suppression while imparting thermal conductivity to PP. Conversely, the other two fillers compromised fire-safety performance. Notably, the composite 5Al 2 O 3 /20Al-IFR/PP exhibited a 90.8 % lower peak heat release rate and an 88.2 % lower peak smoke production rate compared to PP. Additionally, its thermal diffusivity and thermal conductivity were 27.0 % and 48.9 % higher than those of PP, respectively. In short, this work combined molecular design and comprehensive screening to build the thermally conductive PP with high flame retardant efficiency, and relevant mechanisms were also investigated. [ABSTRACT FROM AUTHOR]

This study investigated bacterial removal using TiO2 nanoparticles (NPs) modified with poly-amidoamine dendrimer macromolecule (PAMAM, G3). The PAMAM G3/TiO2 (nanohybrid) was used to specify antibacterial properties via broth microdilution (MBC-Minimum Bactericidal Concentration and MIC-Minimum Inhibitory Concentration-determination), paper disc diffusion, and surface plate count methods. The nanohybrid was characterized via the different techniques. The effects of different factors including initial bacteria count, run time, solution pH, and the nanohybrid concentration were studied. The nanohybrid cytotoxicity was studied on AGS and MKN45 cells line by MTT assay. It was revealed that the nanohybrid was effective in intercepting both bacterial strains growth. The MIC value for S. aureus and E. coli were determined to be 4 and 2 μg/mL, respectively. The MBC value for both strains were calculated to be 32 μg/mL. The results showed removal efficiency of 100% for S. aureus and E. coli bacteria in optimum situation. The decrease in cell viability in the dosage of 32 μg/mL after 72 h treatment for AGS and MKN45 cells line were shown to be 6.2 and 4.6%, respectively. The nanohybrid was able to decrease the S. aureus and E. coli count in solution, which meets the drinking water criterions aligned with WHO guidelines. HIGHLIGHTS A novel poly (amidoamine) generation 3-functionalized TiO2 nanoparticle was prepared.; The antibacterial activity was displayed with particles of a nano size which exhibited a distinct homogenous morphology.; Super high removal efficiency was achevied for bacteria in aqueous solution: E. coli and S. aureus.; FE-SEM analysis revealed morphological variations and the mechanism of killing and trapping the bacteria by nanocomposite.; In the MIC and MBC values range, the cytotoxicity effect of nanocomposite on AGS cell line was relatively lower.;

Herbal medicines have greatly contributed to human health worldwide for thousands of years. In particular, traditional Chinese medicine plays an essential role in the prevention and treatment of COVID-19. With the exponentially increasing use and global attention to herbal medicinal products (HMPs), efficacy and safety have become major public concerns in many countries. In general, the quantification and qualification of quality markers (Q-markers) is the most common way to solve this issue. In the last few decades, small molecules, including flavonoids, terpenes, phenylpropanoids, alkaloids, phenols, and glycosides have been extensively investigated as Q-markers for HMP quality control. With the development of biotechnology in the last decade, scientists have begun to explore HMPs macromolecules, including polysaccharides and DNA, for their establishment as Q-markers. In recent years, supermolecules with stronger biological activities have been found in HMPs. In this review, we summarize and discuss the current Q-markers for HMP quality control; in particular, the possibility of using supermolecules as Q-markers based on structure and activity was discussed.

[Display omitted] Previously, we reported that the combined use of spermine (SPM) and sodium taurocholate (STC) (SPM–STC) significantly improves the oral absorption of rebamipide (BCS class IV) and pulmonary absorption of interferon-α without any harmful histopathological changes in the gastrointestinal tract and lungs, respectively. In the present study, we examined the effect of SPM–STC on the transport of fluorescein isothiocyanate-labeled dextrans (FDs) across Caco-2 cell monolayers and attempted to clarify the mechanisms underlying the transport enhancement caused by SPM–STC. SPM–STC were found to significantly enhance the transport of FDs, while the treatment with SPM–STC was not harmful, and the decrease in transepithelial electrical resistance was transient and reversible. The voltage-clamp study clearly indicated that the opening of the paracellular route could be mainly responsible for the enhanced transport of FD-4. As for the mechanisms, it was found that SPM–STC caused a significant increase in membrane fluidity, which would lead to the enhanced transport of small-molecule drugs such as rebamipide. Since SPM–STC increased intracellular Ca2+ via Ca2+ uptake through Ca2+ channels and Ca2+ release from the endoplasmic reticulum stimulated by the IP 3 pathway, the subsequent possible activation of the MLCK signaling pathway would have led to the contraction of the actin–myosin ring. The rearrangement of tight junction-constituting proteins induced through the MAPK pathway has also been suggested as a possible mechanism for opening tight junctions. Claudin-4, a key protein constituting the tight junction, merged with F-actin along with the plasma membrane, was significantly decreased, which would be at least partial structural evidence for the tight-junction opening. [ABSTRACT FROM AUTHOR]

Wool is sensitive toward the effect of alkaline solutions which are usually used in the dissolution of wool fibers to regenerate keratin. In this investigation, the effect of different alkalis on the chemical composition and the secondary structure of wool was studied. Wool was treated with equivalent amounts of alkali metal hydroxides (lithium, sodium, and potassium hydroxides) as well as alkaline earth metal hydroxides (strontium and barium hydroxides). The effect of these alkalis on wool was monitored using amino acid analysis, elemental analysis, carboxylic content, acid, and base combining capacity, urea-bisulfite and alkali solubility, and FTIR spectroscopy. Further structure elucidation was conducted by thermo-gravimetric analysis, differential scanning calorimetry, and X-ray diffraction pattern. Scanning electron microscopy was used to assign the alteration of the fiber morphology of the alkali-treated wool. The results of this investigation indicate that the effect of the used alkalis on wool is not similar. Cystine, glycine, and the basic amino acids are the most affected species in the treated wool. Some elimination reactions were involved during alkaline treatment of wool; namely decarboxylation, desulphydration, and deamination. The secondary structure of wool treated with Sr(OH)2 and Ba(OH)2 was changed from the α-helical structure into the β-sheet form. [ABSTRACT FROM AUTHOR]

The intact porcine eye globe model was used to demonstrate that transscleral iontophoresis could deliver a small protein, cytochrome c (Cyt c), to the posterior segment and to investigate post-iontophoretic biodistribution in the different ocular compartments. The effects of Cyt c concentration (1, 5, and 10 mg/mL), current density (3.5 and 5.5 mA/cm2), and duration of the current application (10 min and 1, 2, and 4 h) were evaluated. The data confirmed that transscleral iontophoresis enhanced the intraocular delivery of Cyt c under all conditions as compared to passive controls (same setup but without the current application). Increasing the Cyt c concentration resulted in a proportional enhancement in the Cyt c delivery. Increasing the current density from 3.5 to 5.5 mA/cm2 increased iontophoretic delivery at a Cyt c concentration of 10 mg/mL but did not appear to do so at 5 mg/mL; this was attributed in part to the effect of melanin binding. Short duration iontophoresis (10 min, 3.5 mA/cm2) of a 10 mg/mL Cyt c solution created a depot in the sclera. When this was followed by a 4 h incubation period, post-iontophoretic Cyt c diffusion from the sclera resulted in a different biodistribution, and Cyt c could be quantified in the posterior segment. [ABSTRACT FROM AUTHOR]

Biologics address a range of unmet clinical needs, but the occurrence of biologics-induced liver injury remains a major challenge. Development of cimaglermin alfa (GGF2) was terminated due to transient elevations in serum aminotransferases and total bilirubin. Tocilizumab has been reported to induce transient aminotransferase elevations, requiring frequent monitoring. To evaluate the clinical risk of biologics-induced liver injury, a novel quantitative systems toxicology modeling platform, BIOLOGXsym™, representing relevant liver biochemistry and the mechanistic effects of biologics on liver pathophysiology, was developed in conjunction with clinically relevant data from a human biomimetic liver microphysiology system. Phenotypic and mechanistic toxicity data and metabolomics analysis from the Liver Acinus Microphysiology System showed that tocilizumab and GGF2 increased high mobility group box 1, indicating hepatic injury and stress. Tocilizumab exposure was associated with increased oxidative stress and extracellular/tissue remodeling, and GGF2 decreased bile acid secretion. BIOLOGXsym simulations, leveraging the in vivo exposure predicted by physiologically-based pharmacokinetic modeling and mechanistic toxicity data from the Liver Acinus Microphysiology System, reproduced the clinically observed liver signals of tocilizumab and GGF2, demonstrating that mechanistic toxicity data from microphysiology systems can be successfully integrated into a quantitative systems toxicology model to identify liabilities of biologics-induced liver injury and provide mechanistic insights into observed liver safety signals.

Plant polyphenols have many potential applications, for example, in the fields of chemical ecology and human and animal health and nutrition. These biological benefits are related to their bioavailability, bioaccessibility and interactions with other biomolecules, such as proteins, lipids, fibers and amino acids. Polyphenol–protein interactions are well-studied, but less is known about their interactions with lipids and cell membranes. However, the affinity of polyphenols for lipid bilayers partially determines their biological activity and is also important from the usability perspective. The polyphenol–lipid interactions can be studied with several chemical tools including, among others, partition coefficient measurements, calorimetric methods, spectroscopic techniques and molecular dynamics simulation. Polyphenols can variably interact with and penetrate lipid bilayers depending on the structures and concentrations of the polyphenols, the compositions of the lipids and the ambient conditions and factors. Polyphenol penetrating the lipid bilayer can perturb and cause changes in its structure and biophysical properties. The current studies have used structurally different polyphenols, diverse model lipids and various measuring techniques. This approach provides detailed information on polyphenol–lipid interactions, but there is much variability, and the results may even be contradictory, for example, in relation to the locations and orientations of the polyphenols in the lipid bilayers. Nevertheless, by using well-characterized model polyphenols and lipids systematically and combining the results obtained with several techniques within a study, it is possible to create a good overall picture of these fascinating interactions. [ABSTRACT FROM AUTHOR]

Determination of plasma vitamin B12 (B12) is a frequently requested laboratory analysis, mainly employed to establish B12 deficiency. However, an increased level of B12 is a common unexpected finding that may be related to an increased concentration of one of the B12 binding proteins, haptocorrin or transcobalamin. This paper describes the extensive laboratory evaluation of a patient with an elevated level of plasma B12 with various well-established assays. Initial studies suggested the presence of a macromolecule consisting of haptocorrin bound B12. Specific determinations of the B12-binding proteins revealed normal amounts of haptocorrin but a markedly increase in both total and B12 saturated transcobalamin (holo-TC). The results are in accord with the presence of macro-transcobalamin. These experiments reveal that determination of the nature of the B12-macromolecules is troublesome due to differences in assays applied to measure these proteins. In addition, this publication creates awareness of macro-holo-TC as a cause of an unexplained increased B12 level. [ABSTRACT FROM AUTHOR]

This paper reviews the development of inverse emulsion polymerization system used in the oil and gas fields, further discusses the mechanism of inverse emulsion polymerization, analyzes five important factors affecting the process of inverse emulsion polymerization, and expounds in detail the application of inverse emulsion polymerization system in hydraulic fracturing, acidizing fracturing, profile control and water plugging, tertiary oil recovery, well drilling and oil field wastewater treatment, analyzes of green environmental protection and low toxicity is the future development direction of inverse emulsion polymerization system・ Besides, according to the complex process and the influencing factors of inverse emulsion polymerization, this paper also points out the development direction in the future. [ABSTRACT FROM AUTHOR]

Edited MRS sequences are widely used for studying γ‐aminobutyric acid (GABA) in the human brain. Several algorithms are available for modelling these data, deriving metabolite concentration estimates through peak fitting or a linear combination of basis spectra. The present study compares seven such algorithms, using data obtained in a large multisite study. GABA‐edited (GABA+, TE = 68 ms MEGA‐PRESS) data from 222 subjects at 20 sites were processed via a standardised pipeline, before modelling with FSL‐MRS, Gannet, AMARES, QUEST, LCModel, Osprey and Tarquin, using standardised vendor‐specific basis sets (for GE, Philips and Siemens) where appropriate. After referencing metabolite estimates (to water or creatine), systematic differences in scale were observed between datasets acquired on different vendors' hardware, presenting across algorithms. Scale differences across algorithms were also observed. Using the correlation between metabolite estimates and voxel tissue fraction as a benchmark, most algorithms were found to be similarly effective in detecting differences in GABA+. An interclass correlation across all algorithms showed single‐rater consistency for GABA+ estimates of around 0.38, indicating moderate agreement. Upon inclusion of a basis set component explicitly modelling the macromolecule signal underlying the observed 3.0 ppm GABA peaks, single‐rater consistency improved to 0.44. Correlation between discrete pairs of algorithms varied, and was concerningly weak in some cases. Our findings highlight the need for consensus on appropriate modelling parameters across different algorithms, and for detailed reporting of the parameters adopted in individual studies to ensure reproducibility and meaningful comparison of outcomes between different studies. [ABSTRACT FROM AUTHOR]

• Heavy metal (HM) exposure causes ecological imbalance. • Chitosan is highly effective in the adsorption of HMs, both individually and synergistically. • Modification of chitosan through grafting crosslinking for enhanced adsorption of heavy metals from water. • Role of physiochemical parameters in regulating the adsorption efficiency of chitosan. • Limitations of chitosan nanoparticles for heavy metal adsorption. The advancement of industrialization has put the environment at risk of getting saturated with different contaminants. Heavy metals (HMs) emerging from industries, reaching the water bodies expose marine biota to these stressors, leading to negative effects on growth and development. Thus, it is imperative to detoxify the environment from these HM contaminants through degradation, and adsorption. Several mechanical and chemical methods have been developed and implied for the purpose of minimizing HM contamination, but they often give rise to certain by-products that are toxic in nature. Over the years, chitosan has emerged as a potent adsorption material for reducing HM contamination. Chitosan is obtained from multiple natural sources, and owing to its versatile nature, it shows significant capacity for adsorbing different HMs and HM ions. Chitosan is used in synergy with some of the agents to increase its adsorption efficiency. The preparation of graft, beads, functionalized chitosan, crosslinkers, nanoparticles, and nanotubes are some of the potential methods that have been used in modifying chitosan. This paper gives an overview of the ecotoxicological effects of HMs, besides mentioning the fundamental sources of chitosan. The individual role of chitosan and its synergistic role have been discussed in greater detail. Moreover, the limitations associated with chitosan as an HM adsorbent have been delineated. [ABSTRACT FROM AUTHOR]

The incorporation of metal-organic frameworks (MOFs) on textile materials to enhance flame retardancy is of interest and challenge. In this study, an iron-rich MOF (Fe-MOF) was constructed in situ on wool fabric surface through the alternating assembly of ferric metal salt and the carboxylic acid ligand 1,3,5-benzenetricarboxylic acid. The surface morphology, flame retardancy, smoke and heat release performance, thermal stability, and flame-retardant mechanism of the Fe-MOF coated wool fabric were investigated. Square-shaped crystals were observed on the coated wool fabric, indicating successful construction of Fe-MOF on the wool surface. The coated wool fabric with an add-on of 6.8 % exhibited excellent flame retardancy, as evidenced by its self-extinguishing ability during the vertical burning test and a significantly enhanced limiting oxygen index of 32.6 %. Moreover, the coated wool fabric demonstrated a remarkable reduction in heat and smoke production of 23.8 % and 68.4 %, respectively, indicating enhanced fire safety. The analysis of char residue, including thermal stability, surface morphology, iron content, and graphitization degree, supported the formation of ferric oxides as a protective layer, contributing to the improved flame retardancy of the Fe-MOF coated wool in the condensed phase. The in situ construction of Fe-MOF on wool macromolecules offers a promising and innovative approach for developing nonhalogen and nonphosphorus flame-retardant systems. [Display omitted] ● The iron-rich metal-organic frameworks (Fe-MOF) is in situ loaded on wool surface. ● The Fe-MOF coating exhibits high flame retardancy and smoke suppression capacity. ● The Fe-MOF coating mainly functions in the condensed phase. ● The Fe-MOF coating serves as halogen-free, phosphorus-free flame-retardant system. [ABSTRACT FROM AUTHOR]

Unmethylated cytosine-phosphate-guanine (CpG) DNA stimulates mammalian immune cells through recognition by Toll-like receptor 9 (TLR9). Therefore, CpG DNA is expected to be an effective adjuvant for the treatment of immune and allergic diseases. However, challenges, such as low stability against DNase and low delivery efficiency for immune cells, still need to be resolved for the application of CpG DNA. To overcome these challenges, we developed DNA supramolecules consisting of long single-stranded DNA (lss-DNA) synthesized using rolling circle amplification (RCA) and cholesterol-modified DNA (chol-DNA). Lss-DNAs containing multiple CpG motifs were annealed with complementary chol-DNAs to form DNA supramolecules through hydrophobic interactions. Transmission electron microscopy revealed that lss-DNA mixed with chol-DNA formed micrometer-sized DNA supramolecules. The formation of DNA supramolecules increased their stability against DNase compared to lss DNA, which was evaluated using FBS. Furthermore, DNA supramolecules induced three-times higher TNF-α release from RAW264.7 cells than lss-DNA alone. These results demonstrate that DNA supramolecules are efficient delivery carriers of CpG DNA to immune cells. [ABSTRACT FROM AUTHOR]

Purpose: To acquire the mobile macromolecule (MM) spectrum from healthy participants, and to investigate changes in the signals with age and sex. Methods: 102 volunteers (49 M/53 F) between 20 and 69 years were recruited for in vivo data acquisition in the centrum semiovale (CSO) and posterior cingulate cortex (PCC). Spectral data were acquired at 3T using PRESS localization with a voxel size of 30 × 26 × 26 mm3, pre‐inversion (TR/TI 2000/600 ms) and CHESS water suppression. Metabolite‐nulled spectra were modeled to eliminate residual metabolite signals, which were then subtracted out to yield a "clean" MM spectrum using the Osprey software. Pearson's correlation coefficient was calculated between integrals and age for the 14 MM signals. One‐way ANOVA was performed to determine differences between age groups. An independent t‐test was carried out to determine differences between sexes. Results: MM spectra were successfully acquired in 99 (CSO) and 96 (PCC) of 102 subjects. No significant correlations were seen between age and MM signals. One‐way ANOVA also suggested no age‐group differences for any MM peak (all p >.004). No differences were observed between sex groups. WM and GM voxel fractions showed a significant (p <.05) negative linear association with age in the WM‐predominant CSO (R = –0.29) and GM‐predominant PCC regions (R = –0.57) respectively while CSF increased significantly with age in both regions. Conclusion: Our findings suggest that a pre‐defined MM basis function can be used for linear combination modeling of metabolite data from different age and sex groups. [ABSTRACT FROM AUTHOR]

The review is devoted to the analysis of the current state of understanding relationships among the deformation-induced structure transformations, observed rheological properties, and the occurrence of non-linear effects for polymer liquids (melts, solutions, and composites). Three levels of non-linearity are the base for consideration. The first one concerns changes in the relaxation spectra of viscoelastic liquids, which are responsible for weak non-linear phenomena. The second one refers to the strong non-linearity corresponding to such changes in the structure of a medium that leads to the emergence of a new relaxation state of a matter. Finally, the third one describes the deformation-induced changes in the phase state and/or the occurring of bifurcations and instability in flow and reflects the thermodynamic non-linear behavior. From a structure point of view, a common cause of the non-linear effects is the orientation of macromolecules and changes in intermolecular interaction, while a dominant factor in describing fluid dynamics of polymer liquids is their elasticity. The modern understanding of thixotropic effects, yielding viscoplastic materials, deformation-induced phase transition, and the experimental observations, demonstrating direct correlations between the structure and rheology of polymer liquids, are the main objects for discussion. All these topics are reviewed and discussed mainly on the basis of the latest five-year publications. [ABSTRACT FROM AUTHOR]

Microalgal production conducted outdoors using low-cost cultivation media is important for the consolidation of this bioprocess on a large scale. In this context, the use of a chemically defined medium with reduced costs can not only provide nutritional security but also contribute to an increase in the concentration of biomolecules without a loss of microalgal biomass productivity. Thus, this study aimed to evaluate the biomass production and biomolecule concentrations of Spirulina sp. LEB 18 and Synechococcus nidulans LEB 115 in outdoor cultivation using media containing reduced nutrients. Algal performance was assessed in open raceway bioreactors, using three different culture media, namely, BG-11, standard Zarrouk, and a modified Zarrouk [reduction in the sources of carbon (83%), phosphorus (94%), nitrogen (40%), and magnesium (63%) concerning the standard Zarrouk medium]. Cultivation of Spirulina sp. LEB 18 in the modified Zarrouk medium promoted the shortest generation time (2.10 days), with the concentration of carbohydrate produced (37.1%) being 346% higher than that produced using the standard Zarrouk medium (8.3%). Similarly, compared with the Zarrouk medium, the modified Zarrouk medium promoted higher biomass productivity of S. nidulans LEB 115 (0.19 g L−1 d−1) along with a 160% increase in the concentration of carbohydrates (21.6%) produced by this strain. Thus, for the examined microalgal strains, the use of the modified Zarrouk medium enhanced the potential carbohydrate production and maintained the protein concentration above 39%, thereby indicating that this medium would be a promising candidate for the cost-effective large-scale production of microalgal biomass. [ABSTRACT FROM AUTHOR]