A Long-Lasting Triamcinolone-Loaded Microneedle Patch for Prolonged Dermal Delivery.

Background: Scar is an unpleasant skin lesion that occurs following deep wounds or burns. The application of local triamcinolone is a common treatment for scar treatment and prevention, which should be repeated several times in conventional dosage forms. An effort has been made here to provide a prolonged triamcinolone dermal delivery by microneedle technology, which can also be used for wound closure. Objectives: This study aimed to develop a long-lasting polylactic acid (PLA) microneedle patch for the prolonged release of triamcinolone acetonide (TrA) that could potentially be used for closure of wound edges and scar prevention and treatment. Methods: In this study, 3% and 10% TrA-containing polymeric microneedles were fabricated using the micro molding-solvent casting method. Optical microscopy, X-ray diffraction analysis (XRD), Fourier-transform infrared spectroscopy (FT-IR), and differential scanning calorimetry (DSC) were used for the characterization of microneedles. Mechanical strength was evaluated using a compression test and methylene blue staining. Additionally, the insertion depth was determined by histopathological sectioning of human skin samples and also insertion into Parafilm®M as a skin model. The in vitro drug release profile of the microneedles was studied over 34 days, and the kinetic model was determined. The ex-vivo skin permeation of TrA was studied using a Franz-diffusion cell. Results: The TrA-containing PLA microneedles were fabricated with a uniform structure without any failure, deterioration, or loss of needles. Fourier-transform infrared spectroscopy and differential scanning calorimetry showed no interaction between TrA and PLA, and no effect on crystallinity and thermal behavior of TrA on polymer was detected. Microneedles showed appropriate mechanical properties, which were able to penetrate to about 900 - 1000 µm depth. Release profile from the whole body of 10% and 3% microneedle fitted to Higuchi model with cumulative amounts of 625 µg and 201.64 µg over 34 days. Release from the needles followed zero-order kinetic with cumulative amounts of 30.04 µg and 20.36 µg for 10% and 3%, respectively, for 34 days. Permeation was calculated to be 17 µg/day for 10% TrA-containing microneedle. Conclusions: The results suggested that suitable PLA microneedles containing TrA with prolonged release behavior can be successfully constructed with the solvent casting method.

Comprehensive evaluation of fungal-induced corrosion in aluminum alloys by Amorphotheca resinae.

Amorphotheca resinae is a fungus that particularly corrodes aeronautical aluminum alloys, leading to economic issues in various industries. This study aims to investigate the effects of this fungus on the corrosion of four different aluminum alloys, namely 2024, 7075, 5083, and 3105, after 25, 50, and 75 days through scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), 3D profilometry, weight loss (%) measurement, energy dispersive spectrometry (EDS), electrochemical impedance (EIS), and pH changes. After 25 days, the 2024 alloy had the highest mycocorrosion rate (1.3417 mpy), while alloy 3105 had an undetectable value on this day. According to the EIS test, the 3105 alloy had the highest level of resistance (1.12 × 105 Ω cm2) to corrosion, while the 2024 alloy was the most susceptible (7138 Ω cm2). The qualitative data from SEM, CLSM, and 3D profilometry also confirmed the quantitative findings where the surface pits on the 2024 alloy were deeper than those of other alloys. Overall, the results showed that the lowest and highest corrosion rates mediated by A. resinae belonged to 3105 and 2024 alloys, respectively. These findings could have significant implications for industries that use aluminum alloys and might help in developing strategies to prevent or control biocorrosion.

Corrosion behavior of predominant Halodesulfovibrio in a marine SRB consortium and its mitigation using ZnO nanoparticles.

Formation of Sulfate Reducing Bacteria (SRB) biofilm accelerates microbiologically influenced corrosion (MIC). The aim of this study was to investigate both the corrosivity of a marine SRB consortium on carbon steel coupons and its mitigation in the presence of ZnO. Metagenomics analysis revealed that Halodesulfovibrio (78.9%) was predominant and could be related to MIC. The analysis also showed a remarkable shift from a highly corrosive SRB consortium in the control bioreactors to a far less corrosive consortium when ZnO was added to the bioreactors. Further results indicated that the corrosion rate of the SRB consortium was 8.17 mpy on the carbon steel coupons. In the ZnO-treated bioreactors, the count of SRB and MIC in the carbon steel coupons simultaneously reduced. Moreover, Confocal Laser Scanning Microscopy and profilometry analysis determined that ZnO could significantly decrease the amount of biofilm and the corrosion rate. Electrochemical experiments revealed higher corrosion current density (icorr) and lower charge transfer resistance (Rct) in the control bioreactors relative to the ZnO-treated bioreactors. We introduce Halodesulfovibrio as a potentially important corrosive genus in a marine SRB consortium. Additionally, ZnO could be considered a proper candidate to control the corrosion induced by Halodesulfovibrio.

Corticosteroid-loaded chitosan-based in-situ forming gel combined with microneedle technology for improvement of burn eschar wound healing.

Burn is one of the most common skin injuries and accounts for 300,000 deaths annually. Debridement and antibiotic therapy are major burn treatments, however, as debridement is not always possible and many drugs have poor penetration into necrotic tissue, permeation enhancement is acquired. Another challenge is the short duration of topically applied drugs. This study aims to address both problems by combining in-situ forming gels and microneedles. A chitosan-based in-situ forming gel of hydrocortisone was applied to human burn eschar using microneedles. The formulation was optimized using Design-Expert software. Formulation characterization was done in terms of gelling time and temperature, thermal analysis, release phenomenon, rheology, texture analysis, and stability. Finally, animal studies on mice burn wound treatment were conducted. Results showed that optimized formulation controlled the drug release, and wherever microneedle was used, drug permeation and flux increased (P-value < 0.05). In all ex-vivo and in-vivo stages, gel plus microneedle (length of 1.5 mm and application mode of 2) produced the best results concerning increased flux and faster recovery of burn eschar. In conclusion, the in-situ forming gel with appropriate texture, quality, and stability in combination with microneedle can be a good candidate for the controlled release of drugs in third-degree burn eschars.

Design and Characterization of an Osmotic Pump System for Optimal Feeding and pH Control in E. coli Culture to Increase Biomass.

Background: Batch cultures used for various purposes, such as expression screening and recombinant protein production in laboratories, usually have some drawbacks due to the bolus addition of carbon sources, such as glucose and buffers, that lead to overflow metabolism, decreased pH, high osmolality, low biomass yield, and low protein production. Objectives: This study aimed to overcome the problems of batch culture using the controlled release concept by a controlled porosity osmotic pump (CPOP) system. Methods: The CPOP was formulated with glucose as a carbon source feeding and sodium carbonate as a pH modifier in the core of the tablet that was coated with a semipermeable membrane containing cellulose acetate and polyethylene glycol (PEG) 400. The release rate was regulated with Eudragit L100 as a retardant agent in the core and PEG 400 as a pore-former agent in the coating membrane. Fourier-transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM) were used to elucidate compatibility between components and release mechanism, respectively. The in-vitro release of glucose and Na2CO3 studies were performed for 24 hours in a mineral culture medium (M9). Then, the effectiveness of CPOP in the growth of Escherichia coli (E. coli BL21) as a microorganism model was evaluated. Glucose consumption, changes in medium's pH, and acetate concentration as a by-product were also monitored during the bacterial growth. Results: Fourier-transform infrared spectroscopy confirmed the compatibility between the components in the osmotic pump, and SEM elucidated the release mechanism due to in-situ delivery pores created by dissolving soluble components (PEG 400) on the coated membrane upon contact with the dissolution medium. The in-vitro release studies indicated that the osmotic pump was able to deliver glucose and sodium carbonate in a zero-order manner. The use of CPOP in E. coli (BL21) cultivation resulted in a statistically significant improvement in biomass (over 80%), maintaining the pH of the medium (above 6.8) during the exponential phase, and reducing metabolic by-product formation (acetate), compared to bolus feeding (P < 0.05). Conclusions: The use of CPOP, which is capable of controlled release of glucose as a carbon source and sodium carbonate as a pH modifier, can overcome the drawbacks of bolus feeding, such as decreased pH, increased acetate concentration, and low productivity. It has a good potential for commercialization.

Unlocking the potential of soil microbial communities for bioremediation of emerging organic contaminants: omics-based approaches.

The remediation of emerging contaminants presents a pressing environmental challenge, necessitating innovative approaches for effective mitigation. This review article delves into the untapped potential of soil microbial communities in the bioremediation of emerging contaminants. Bioremediation, while a promising method, often proves time-consuming and requires a deep comprehension of microbial intricacies for enhancement. Given the challenges presented by the inability to culture many of these microorganisms, conventional methods are inadequate for achieving this goal. While omics-based methods provide an innovative approach to understanding the fundamental aspects, processes, and connections among microorganisms that are essential for improving bioremediation strategies. By exploring the latest advancements in omics technologies, this review aims to shed light on how these approaches can unlock the hidden capabilities of soil microbial communities, paving the way for more efficient and sustainable remediation solutions.

Design of a two functional permeable reactive barrier for synergistic enzymatic and microbial bioremediation of phenol-contaminated waters: laboratory column evaluation : Enzymatic and microbial bioremediation of phenol in a bilayer permeable reactive barrier.

The present study aimed to develop a system using a combination of enzymatic and microbial degradation techniques for removing phenol from contaminated water. In our prior research, the HRP enzyme extracted from horseradish roots was utilized within a core-shell microcapsule to reduce phenolic shock, serving as a monolayer column. To complete the phenol removal process, a second column containing degrading microorganisms was added to the last column in this research. Phenol-degrading bacteria were isolated from different microbial sources on a phenolic base medium. Additionally, encapsulated calcium peroxide nanoparticles were used to provide dissolved oxygen for the microbial population. Results showed that the both isolated strains, WC1 and CC1, were able to completely remove phenol from the contaminated influent water the range within 5 to 7 days, respectively. Molecular identification showed 99.8% similarity for WC1 isolate to Stenotrophomonas rizophila strain e-p10 and 99.9% similarity for CC1 isolate to Bacillus cereus strain IAM 12,605. The results also indicated that columns using activated sludge as a microbial source had the highest removal rate, with the microbial biofilm completely removing 100% of the 100 mg/L phenol concentration in contaminated influent water after 40 days. Finally, the concurrent use of core-shell microcapsules containing enzymes and capsules containing Stenotrophomonas sp. WC1 strain in two continuous column reactors was able to completely remove phenol from polluted water with a concentration of 500 mg/L for a period of 20 days. The results suggest that a combination of enzymatic and microbial degrading systems can be used as a new system to remove phenol from polluted streams with higher concentrations of phenol by eliminating the shock of phenol on the microbial population.

Comprehensive network of stress-induced responses in Zymomonas mobilis during bioethanol production: from physiological and molecular responses to the effects of system metabolic engineering.

Nowadays, biofuels, especially bioethanol, are becoming increasingly popular as an alternative to fossil fuels. Zymomonas mobilis is a desirable species for bioethanol production due to its unique characteristics, such as low biomass production and high-rate glucose metabolism. However, several factors can interfere with the fermentation process and hinder microbial activity, including lignocellulosic hydrolysate inhibitors, high temperatures, an osmotic environment, and high ethanol concentration. Overcoming these limitations is critical for effective bioethanol production. In this review, the stress response mechanisms of Z. mobilis are discussed in comparison to other ethanol-producing microbes. The mechanism of stress response is divided into physiological (changes in growth, metabolism, intracellular components, and cell membrane structures) and molecular (up and down-regulation of specific genes and elements of the regulatory system and their role in expression of specific proteins and control of metabolic fluxes) changes. Systemic metabolic engineering approaches, such as gene manipulation, overexpression, and silencing, are successful methods for building new metabolic pathways. Therefore, this review discusses systems metabolic engineering in conjunction with systems biology and synthetic biology as an important method for developing new strains with an effective response mechanism to fermentation stresses during bioethanol production. Overall, understanding the stress response mechanisms of Z. mobilis can lead to more efficient and effective bioethanol production.

Fungal-bacterial consortia: A promising strategy for the removal of petroleum hydrocarbons.

Nowadays, petroleum hydrocarbon pollution is one of the most widespread types of contamination that poses a serious threat to both public health and the environment. Among various physicochemical methods, bioremediation is an eco-friendly and cost-effective way to eliminate petroleum hydrocarbon pollutants. The successful degradation of all hydrocarbon components and the achievement of optimal efficiency are necessary for the success of this process. Using potential microbial consortia with rich metabolic networks is a promising strategy for addressing these challenges. Mixed microbial communities, comprising both fungi and bacteria, exhibit diverse synergistic mechanisms to degrade complex hydrocarbon contaminants, including the dissemination of bacteria by fungal hyphae, enhancement of enzyme and secondary metabolites production, and co-metabolism of pollutants. Compared to pure cultures or consortia of either fungi or bacteria, different studies have shown increased bioremediation of particular contaminants when combined fungal-bacterial treatments are applied. However, antagonistic interactions, like microbial competition, and the production of inhibitors or toxins can observed between members. Furthermore, optimizing environmental factors (pH, temperature, moisture, and initial contaminant concentration) is essential for consortium performance. With the advancements in synthetic biology and gene editing tools, it is now feasible to design stable and robust artificial microbial consortia systems. This review presents an overview of using microbial communities for the removal of petroleum pollutants by focusing on microbial degradation pathways, and their interactions. It also highlights the new strategies for constructing optimal microbial consortia, as well as the challenges currently faced and future perspectives of applying fungal-bacterial communities for bioremediation.

Assessing the efficiency and microbial diversity of H2S-removing biotrickling filters at various pH conditions.

This study aimed to investigate the operation of three parallel biotrickling filters (BTFs) in removing H2S at different pH conditions (haloalkaliphilic, neutrophilic, and acidophilic) and their associated microbial population in the biodesulfurization process. BTF columns were inoculated with enriched inoculum and experiments were performed by gradually reducing Empty Bed Retention Time (EBRT) and increasing inlet concentration in which the maximum removal efficiency and maximum elimination capacity in EBRT 60 s reached their maximum level in haloalkaline condition (91% and 179.5 g S-H2S m-3 h-1). For visualizing the attached microbial biofilms on pall rings, Scanning Electron Microscopy (SEM) was used and microbial community structure analysis by NGS showed that the most abundant phyla in haBTF, nBTF, and aBTF belong to Gammaproteobacteria, Betaproteobacteria, and Acidithiobacillia, respectively. Shannon and Simpson indexes evaluation showed a lower diversity of bacteria in the aBTF reactor than that of nBTF and haBTF and beta analysis indicated a different composition of bacteria in haBTF compared to the other two filters. These results indicated that the proper performance of BTF under haloalkaliphilic conditions is the most effective way for H2S removal from air pollutants of different industries.

Acceleration a yeast-based biodegradation process of polyethylene terephthalate microplastics by Tween 20: Efficiency, by-product analysis, and metabolic pathway Prediction.

Polyethylene terephthalate is a widely produced plastic polymer that exhibits considerable biodegradation resistance, making its derived microplastics ubiquitous environmental pollutants. In this study, a new yeast strain (Vanrija sp. SlgEBL5) was isolated and found to have lipase and esterase-positive capabilities for degrading polyethylene terephthalate microplastics. This isolate changed the microplastic surface charge from -19.3 to +31.0 mV and reduced more than 150 µm of its size in addition to reducing the intensity of the terephthalate, methylene, and ester bond functional groups of the polymer in 30 days. Tween 20 as a chemical auxiliary treatment combined with biodegradation increased the microplastic degradation rate from 10 to 16.6% and the thermal degradation rate from 85 to 89%. Releasing less potentially hazardous by-products like 1,2 diethyl-benzene despite the higher abundance of long-chain n-alkanes, including octadecane and tetracosane was also the result of the bio + chemical treatment. Altogether, the findings showed that Vanrija sp. SlgEBL5 has the potential as a biological treating agent for polyethylene terephthalate microplastics, and the simultaneous bio + chemical treatment enhanced the biodegradation rate and efficiency.

Assessment of parent and alkyl -PAHs in surface sediments of Iranian mangroves on the northern coast of the Persian Gulf: Spatial accumulation distribution, influence factors, and ecotoxicological risks.

Spatial patterns, potential origins, and ecotoxicological risk of alkylated (APAH) -and parent -(PPAH) polycyclic aromatic hydrocarbons (PAHs) were studied in mangrove surface sediments along the northern coasts of the Persian Gulf, Iran. The mean total concentrations (ngg-1dw) ∑32PAH, ∑PPAHs and ∑APAHs in sediments were 3482 (1689-61228), 2642 (1109-4849), and 840 (478-1273), respectively. The spatial variability was similar among these PAH groups, with the highest levels occurring in Nayband National Marine Park (NNMP). Physicochemical environmental factors, such as sediment grain size, and total organic carbon (TOC) contents, are significant factors of PAH distribution. These findings suggest that PAH pollution level is moderate-to-high, supporting the current view that mangrove ecosystems are under intensive anthropogenic impacts, such as petrochemical, oil and gas loads, port activities, and urbanization. Non-parametric multidimensional scaling (NPMDS) ordination demonstrated that NNMP mangrove is the critical site exhibiting high loading of PAH pollutants. Here, for the first time in this region, Soil quality guidelines (SQGs), Toxic equivalency quotient (TEQ), Mutagenic equivalency quotient (MEQ), and composition indices comprising Mean maximum permissible concentration quotient (m-MPC-Q), and Mean effect range median quotient (m-ERM-Q) methods were used to have a comprehensive risk assessment for PAH compounds and confirmed medium-to-high ecological risks of PAHs in the study area, particularly in the western part of the Gulf, highlighting the industrial impacts on the environment.

Protein-based microneedles for biomedical applications: A systematic review.

Microneedles are minimally-invasive devices with the unique capability of bypassing physiological barriers. Hence, they are widely used for different applications from drug/vaccine delivery to diagnosis and cosmetic fields. Recently, natural biopolymers (particularly carbohydrates and proteins) have garnered attention as safe and biocompatible materials with tailorable features for microneedle construction. Several review articles have dealt with carbohydrate-based microneedles. This review aims to highlight the less-noticed role of proteins through a systematic search strategy based on the PRISMA guideline from international databases of PubMed, Science Direct, Scopus, and Google Scholar. Original English articles with the keyword "microneedle(s)" in their titles along with at least one of the keywords "biopolymers, silk, gelatin, collagen, zein, keratin, fish-scale, mussel, and suckerin" were collected and those in which the proteins undertook a structural role were screened. Then, we focused on the structures and applications of protein-based microneedles. Also, the unique features of some protein biopolymers that make them ideal for microneedle construction (e.g., excellent mechanical strength, self-adhesion, and self-assembly), as well as the challenges associated with them were reviewed. Altogether, the proteins identified so far seem not only promising for the fabrication of "better" microneedles in the future but also inspiring for designing biomimetic structural biopolymers with ideal characteristics.

COVID-19 vaccines breakthrough infection and adverse reactions in medical students: a nationwide survey in Iran.

Introduction: There are different types of COVID-19 vaccines approved worldwide. Since no national studies focus on vaccine-related adverse reactions and breakthrough cases, this study aimed to investigate the rate of adverse events and COVID-19 infection in medical students in Iran. Methods: This retrospective cohort study included Iranian medical students who received two doses of COVID-19 vaccines. The medical team gathered the demographic characteristics, comorbidities, type of vaccine, adverse events following vaccination, and history of COVID-19 infection data through a phone interview. The frequency of adverse events and breakthrough infection was stratified by vaccine type (ChAdOx1-S, Gam-COVID-Vac, and BIBP-CorV). Results: A total of 3,591 medical students enrolled in this study, of which 57.02% were females, with a mean age of 23.31 + 4.87. A PCR-confirmed and suspicious-for-COVID-19 breakthrough infection rate of 4.51 and 7.02% was detected, respectively. There was no significant relation between breakthrough infection and gender, BMI, blood groups, and comorbidities. However, there was a significant difference in breakthrough infection rate among different types of vaccines (p = 0.001) and history of COVID-19 infection (p = 0.001). A total of 16 participants were hospitalized due to COVID-19 infection after vaccination for reasons such as dyspnea, abnormal imaging, or decreased oxygen saturation. No severe infection or death was observed in the studied population. Conclusion: Vaccination prevented severe COVID-19 infection, although a high breakthrough infection rate was evident among Iranian medical students during the Delta variant's peak. Vaccine effectiveness may be fragile during emerging new variants and in high-exposure settings. Moreover, adverse events are rare, and the benefits of vaccination outweigh the side effects. However, many limitations challenged this study, and the results should be cautious.

In-vivo and in-vitro wound healing and tissue repair effect of Trametes versicolor polysaccharide extract.

Regarding different medical benefits of fungi, using the medical mushroom extracts as wound-healing agents is gaining popularity. This study, evaluated the wound healing characteristics of Trametes versicolor. Anti-oxidant activity addressed by employing the DPPH (2,2-diphenyl-1-picrylhydrazyl) assay resulting 53.7% inhibitory effect. Besides, for anti-microbial ability determination, the MIC (Minimum Inhibitory Concentration) of extract measured which Escherichia coli growth was inhibited at 1.1 mg/ml, and Staphylococcus aureus did not grow at 4.38 mg/ml of extract. The MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) method indicated dose dependence of the extract with 63 ± 3% and 28 ± 3% viability at 1250 µg/ml and 156.25 µg/ml of extract, which higher concentration caused higher cell viability. The outcome of gene expression analysis determined that overall expression of FGF2 (Fibroblast Growth Factor 2), IL-1ß (Interleukin-1ß), and TGF-ß1 (Transforming Growth Factor-ß1) was 4 times higher at 48 h than at 24 h in treated cells, suggesting a stimulating effect on cell growth. An in-vivo animal model suggested enhanced wound healing process after treatment with 0.01 g of extract. Furthermore, the number of fibroblasts, epidermal thickness, and collagen fiber was respectively 2, 3, and threefold higher in treated mice when compared to untreated mice. The treated wounds of mice showed 100% and 60% of untreated mice of healing within 14 days. The results of this research show promise for the fungus-based wound healing treatments, which may help with tissue regeneration and the healing of cutaneous wounds.

Fabrication of controlled-release silver nanoparticle polylactic acid microneedles with long-lasting antibacterial activity using a micro-molding solvent-casting technique.

Most topical drug delivery techniques do not provide therapeutic concentrations for treatment of surgical site and other local infections and, therefore, require some kind of enhancement, such as physical methods like microneedles, the subject of the present investigation. Here, controlled-release long-lasting antibacterial polylactic acid (PLA) microneedles containing 1, 3, and 5% silver nanoparticles (AgNP) were prepared using micro-molding solvent-casting technique. Microneedles were characterized using optical microscopy, SEM, FTIR, XRD, and DSC. Also, mechanical strength, barrier disruption ability, insertion depth, in-vitro release kinetics, antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa, and silver permeation through rat skin were studied. Microneedles showed good mechanical strength with no signs of failure at an optimum PLA concentration of 25% (w/v). FTIR revealed no chemical interaction between ingredients, and XRD confirmed presence of AgNP in microneedles. Microneedles penetrated the skin model at depth of up to 1143 µm resulting 5-7 times increase in transepidermal water loss (TEWL). Release studies showed 2.2, 6.8, and 8.1 µg silver release from the whole body (obeying Higuchi's release model) and 0.33, 0.45, and 0.78 µg from the needles alone (obeying Fickian-cylindrical type release) for 1, 3, and 5% AgNP microneedles, respectively. Also, prolonged antibacterial activity (for 34 days) was observed. Skin studies over 72 h indicated that besides needles, silver is also released from the baseplate which had a marginal share in total silver permeation through the skin. In conclusion, a straightforward solvent-casting technique can be used to successfully prepare strong AgNP-containing PLA microneedles capable of long-lasting antibacterial activity.

Comparison of bioleaching of a sulfidic copper ore (chalcopyrite) in column percolators and in stirred-tank bioreactors including microbial community analysis.

Chalcopyrite is the most abundant Cu-sulfide and economically the most important copper mineral in the world. It is known to be recalcitrant in hydrometallurgical processing and therefore chalcopyrite bioleaching has been thoroughly studied for improvement of processing. In this study, the microbial diversity in 22 samples from the Sarcheshmeh copper mine in Iran was investigated via 16S rRNA gene sequencing. In total, 1063 species were recognized after metagenomic analysis including the ferrous iron- and sulfur-oxidizing acidophilic genera Acidithiobacillus, Leptospirillum, Sulfobacillus and Ferroplasma. Mesophilic as well as moderately thermophilic acidophilic ferrous iron- and sulfur-oxidizing microorganisms were enriched from these samples and bioleaching was studied in shake flask experiments using a chalcopyrite-containing ore sample from the same mine. These enrichment cultures were further used as inoculum for bioleaching experiments in percolation columns for simulating heap bioleaching. Addition of 100 mM NaCl to the bioleaching medium was assessed to improve the dissolution rate of chalcopyrite. For comparison, bioleaching in stirred tank reactors with a defined microbial consortium was carried out as well. While just maximal 32% copper could be extracted in the flask bioleaching experiments, 73% and 76% of copper recovery was recorded after 30 and 10 days bioleaching in columns and bioreactors, respectively. Based on the results, both, the application of moderately thermophilic acidophilic bacteria in stirred tank bioreactors, and natural enrichment cultures of mesoacidophiles, with addition of 100 mM NaCl in column percolators with agglomerated ore allowed for a robust chalcopyrite dissolution and copper recovery from Sarcheshmeh copper ore via bioleaching.

Investigating biodegradation of polyethylene and polypropylene microplastics in Tehran DWTPs.

Microplastic (MP) pollution is a growing concern and various methods are being sought to alleviate the level of pollution worldwide. This study investigates the biodegradation capacity of MPs by indigenous microorganisms of raw water from Tehran drinking water treatment plants. By exposing polypropylene (PP) and polyethylene (PE) MPs to selected microbial colonies, structural, morphological, and chemical changes were detected by scanning electron microscope (SEM), cell weight measurement, Fourier transform infrared (FTIR), Raman spectroscopy test, and thermal gravimetric analysis (TGA). Selected bacterial strains include Pseudomonas protegens strain (A), Bacillus cereus strain (B), and Pseudomonas protegens strain (C). SEM analysis showed roughness and cracks on PP MPs exposed to strains A and C. However, PE MPs exposed to strain B faced limited degradation. In samples related to strain A, the Raman spectrum was completely changed, and a new chemical structure was created. Both TGA and FTIR analysis confirmed changes detected by Raman analysis of PP and PE MPs in chemical changes in this study. The results of cell dry weight loss for microbial strains A, B, and C were 13.5, 38.6, and 25.6%, respectively. Moreover, MPs weight loss was recorded at 32.6% for PP MPs with strain A, 13.3% for PE MPs with strain B, and 25.6% for PP MPs with strain C.

A Mechanistic Study on the Fluidization and Enhancement Effects of Cineole Toward Stratum Corneum Intercellular Lamellar Lipids: A Liquid Crystalline Model Approach.

Background: The stratum corneum (SC) serves as the primary barrier for permeation in human skin. Penetration enhancers, such as 1,8-cineole, are utilized to enhance the permeation of drugs. Cineole increases the permeation of chemicals through different mechanisms. However, its mechanism, particularly at high concentrations, has not been well-studied and is the subject of the present investigation. Objectives: In continuation of our previous studies, the present investigation aims to elucidate the mechanism of action and concentration dependency of the effects of 1,8-cineole on the structure, diffusional properties, and partitioning behavior of the SC at high concentrations. This will be achieved through lamellar liquid crystalline models and ex-vivo skin studies. Methods: A lamellar liquid crystalline lipid matrix model in the presence (25 - 90%, w/w) and absence of cineole was prepared from SC lipids and characterized by X-ray diffraction, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and polarized light microscopy (PLM) studies. Release of the model lipophilic drug (diazepam) from cineole and cineole-treated matrices and the permeation of the drug from cineole and cineole-containing matrices (as a vehicle similar to the stratum corneum lipids) through excised rat skin were studied. Drug assay was performed by HPLC. Results: The PLM, DSC, and X-ray studies showed that the model matrix had a lamellar gel-liquid crystalline structure, and cineole fluidized the structure concentration-dependently and created other mesomorphic textures, such as myelinic figures. Release experiments showed that diffusion coefficients remained almost constant at high cineole concentrations of 40-90%, suggesting similar fluidization states. Skin permeation studies indicated that the diffusion coefficient (estimated from lag-time) increased concentration-dependently and played a role in permeability coefficient (Kp) increments alongside the increased partitioning of the model drug into the skin. Data suggest that high concentrations of cineole at the skin surface might not provide enough cineole in the skin for full fluidization, despite the similarity of the vehicle to SC lipids and even at high concentrations. Conclusions: The enhancement effect of cineole is concentration-dependent and might reach maximum fluidization at certain concentrations, but this maximum might not be easily achievable when cineole is used in formulations as pure or in a vehicle.