Uncontrolled Release Research Articles

Clinical Case of a Patient with Acute Tricuspid Valve Infective Endocarditis and A Multiplex Approach to Evaluation of The Complication Risk

Infective endocarditis (IE) is characterized by the difficulty of diagnosis, treatment and risk assessment of an unfavorable prognosis. Currently there are no approved scales and calculators for the risk of complications and death that help the practitioner make decisions, especially in patients with isolated right-sided IE. For right-sided IE, the timing of successful surgical treatment remains uncertain. Previously developed risk calculators (Italian Rizzi calculator and French Hubert) are poorly validated in a wide population of patients with IE, especially for right-sided IE. One of the required parameters of calculators is the determination of etiological affiliation. However, with negative results of microbiological studies reaching 56-83 %, this parameter becomes uninformative. Moreover, existing risk assessment tools do not take into account the activity of the disease (including laboratory activity), which intuitively is an important guideline for every doctor in decision-making. At the moment, there is a great need for the introduction of molecular biological methods to improve the quality of etiological diagnosis and in-depth study of possible biomarkers from simple (neutrophil/lymphocytic, platelet/lymphocytic and systemic immuno-inflammatory index) to more complex (neutrophil extracellular traps, cytokine profile). We present a clinical case of a young patient with acute tricuspid valve IE with giant vegetation (28 mm), complicated by severe valvular insufficiency without signs of heart failure, recurrent embolic syndrome in the pulmonary artery system with the formation of pulmonary hypertension, determining indications for cardiac surgical treatment. The etiological affiliation of IE to Staphylococcus aureus was established only by PCR. The urgent timing of intervention was determined based on an increase in new markers — neutrophil/lymphocytic index ≥20.0, systemic immuno-inflammatory index ≥2314.0 and neutrophil extracellular traps ≥14.2, indicating an extremely high risk of death. A fundamental pathohistological study of the tissue material revealed a low content of intact CD86+ proinflammatory macrophages, probably associated with their excessive destruction and uncontrolled release of copious amounts of proinflammatory cytokines, which led to rapid and severe damage to the tricuspid valve. Thus, modern management of patients with IE should be multiplex using current methods of etiological and imaging diagnostics, and aimed at early detection of patients at adverse risk for a timely differentiated approach to conservative or cardiac surgical treatment tactics.

An Evaluation of the Subcutaneous Depot Release of TV-46000, A Novel Long-Acting Injectable (LAI) Formulation of Risperidone, Under Extreme Conditions in Dogs, Minipigs and Humans

Background: TV-46000 (Uzedy, Teva), a long-acting subcutaneous antipsychotic, is an injectable formulation of risperidone and is approved by the FDA for the treatment of schizophrenia in adults. Its innovative copolymer-based drug delivery depot technology (licensed from MedinCell, Jacou, France) allows for plasma concentrations of the total active moiety of risperidone (TAM) to reach clinically relevant levels within 6–24 h and the maintenance of these therapeutic levels with monthly and bimonthly dosing regimens. Objective: As part of the development program for TV-46000, the effect of extrinsic factors of manipulation on the site of injection, and on the pharmacokinetic (PK) profile of TAM following TV-46000 administration was evaluated. Methods: Studies were conducted assessing the effect of heat and rubbing with male Gottingen minipigs and the effect of rubbing with male beagle dogs. A pilot clinical study in healthy volunteers was performed to evaluate the effect of rubbing. Results: These investigations showed that heating or rubbing of the TV-46000 sc injection site immediately post-injection had no clinically meaningful impact on safety and no burst or uncontrolled release was evident. Furthermore, no impact of injection site manipulation on TAM exposure was observed after depot formation (≥0.5 h post-injection). Conclusions: The observed similarity in findings between the animal and human studies supports the suitability of animal models for evaluation of the effect of extrinsic factors on injection sites and its translatability to clinical settings.

An electroanalytical sensor for the detection of antibiotic cefoperazone sodium sulbactam sodium residue in wastewater.

The misuse and uncontrolled release of pharmaceuticals into water bodies lead to environmental challenges and the development of resistance, thereby reducing their effectiveness. To mitigate these problems, it is essential to identify pharmaceuticals in water sources and eliminate them prior to human use. This study presents the designing of a novel nanosensor for the detection of the antibiotic Cefoperazone Sodium Sulbactam Sodium (CSSS). The nanosensor was prepared by modifying the surface of a glassy carbon electrode (GCE) with the nanoparticles of NiO and MWCNTs. A green synthetic method was applied for the synthesis of NiO nanoparticles. Their structural and morphological characterization was conducted using X-ray diffraction and scanning electron microscopy, while optical properties were assessed through UV-vis spectroscopy. NiO nanoparticles in conjunction with MWCNTs enhanced the sensitivity of the GCE for the detection of CSSS. Electrochemical impedance spectroscopy revealed efficient charge transport through the designed sensing platform designated as NiO/MWCNTs/GCE. Square wave voltammetry demonstrated an eightfold increase in peak current intensity of CSSS at the NiO/MWCNTs/GCE as compared to the unmodified GCE. The electrochemical analysis of CSSS in solution of different pH indicated the involvement of protons during electron transfer reactions of CSSS. The limit of detection of CSSS with a value of 3.31 nM was obtained at the designed sensing platform under optimized experimental conditions. The current investigations combine advanced materials with principles of green chemistry, significantly enhancing efforts in wastewater remediation from antibiotic drugs.

Immune responses to avian influenza viruses in chickens.

Chickens are a key species in both the manifestation of avian influenza and the potential for zoonotic transmission. Avian influenza virus (AIV) infection in chickens can range from asymptomatic or mild disease with low pathogenic AIVs (LPAIVs) to systemic fatal disease with high pathogenic AIVs (HPAIVs). During AIV infection in chickens, Toll-like receptor 7 and melanoma differentiation-associated gene 5 are upregulated to detect the single-stranded ribonucleic acid genomes of AIV, triggering a signaling cascade that produces interferons (IFNs) and pro-inflammatory cytokines. These inflammatory mediators induce the expression of antiviral proteins and recruit immune system cells, such as macrophages and dendritic cells, to the infection site. AIV evades these antiviral responses primarily through its non-structural protein 1, which suppresses type I IFNs, influencing viral pathogenicity. The uncontrolled release of pro-inflammatory cytokines may contribute to the pathogenicity and high mortality associated with HPAIV infections. AIV modulates apoptosis in chicken cells to enhance its replication, with variations in apoptosis pathways influenced by viral strain and host cell type. The presentation of AIV antigens to T and B cells leads to the production of neutralizing antibodies and the targeted destruction of infected cells by CD8+ T cells, respectively, which enhances protection and establishes immunological memory. This review explores the diverse innate and adaptive immune responses in chickens to different AIVs, focusing on the dynamics of these responses relative to protection, susceptibility, and potential immunopathology. By understanding these immune mechanisms, informed strategies for controlling AIV infection and improving chicken health can be developed.

Core-Shell Nanoparticles with Sequential Drug Release Depleting Cholesterol for Reverse Tumor Multidrug Resistance.

Multidrug resistance (MDR) facilitates tumor recurrence and metastasis, which has become a main cause of chemotherapy failure in clinical. However, the current therapeutic effects against MDR remain unsatisfactory, mainly hampered by the rigid structure of drug-resistant cell membranes and the uncontrolled drug release. In this study, based on a sequential drug release strategy, we engineered a core-shell nanoparticle (DOX-M@CaP@ATV@HA) depleting cholesterol for reverse tumor MDR. DOX-M@CaP@ATV@HA could accurately target tumor cells due to the active targetability of hyaluronic acid (HA) toward CD44 receptors. The calcium phosphate (CaP) shell was cleaved in the lysosomal acidic environment so that the cholesterol-lowering drug atorvastatin (ATV) was rapidly released to diminish cholesterol and P-glycoprotein (P-gp) level on the membrane, thereby boosting tumor cell drug uptake. Next, doxorubicin (DOX) was gradually released from the hydrophobic core of the mPEG-DSPE micelle, inflicting irreversible DNA damage and triggering apoptosis. The nanosystem was proven both in vitro and in vivo to reverse MDR effectively and exhibited a remarkable therapeutic efficacy on drug-resistant tumors with high biosafety. In conclusion, DOX-M@CaP@ATV@HA effectively reverses MDR via cholesterol depletion, which provides an innovative strategy for tumor MDR treatment.

Exploring Ionic Liquid-based Liquid-Liquid Extraction as Benign Alternative for Sustainable Wastewater Treatment

The uncontrolled release of industrial effluents containing micropollutants (MPs), dyes, and heavy metal ions contaminates natural water bodies posing threats to health and the environment. Conventional treatment methods often struggle with challenges such as prolonged processing time, low specificity, and risk of producing secondary pollutants. Liquid-liquid extraction (LLE) technique utilizing ionic liquids (ILs) has emerged as a viable alternative for the elimination of contaminants from wastewater. ILs, characterized by minimal volatility and tunable physicochemical properties, facilitate the precise elimination of contaminants from industrial effluent. IL-LLE streamlines the experimental setup, lowers energy consumption, promotes recyclability for reuse, enhances mechanistic understanding, and hence provides a sustainable alternative to industrial effluent treatment. This review provides a comprehensive analysis of IL-LLE approaches for wastewater treatment, commencing with an overview of the historical evolution of ILs, tracing their progression from initial research to contemporary and advanced applications. The article primarily examines the practical applications of IL-LLE, demonstrating how these approaches are employed to efficiently remove diverse contaminants from both simulated and actual industrial wastewater samples. As a whole, the review consolidates the versatility and efficiency of IL-based LLE in addressing various challenges in wastewater treatment.

Loading curcumin on hyperbranched polymers functionalized Zein via the phenol-yne click reaction as pH-responsive drug delivery system for chemotherapy and photodynamic therapy.

Zein and its complexes have been considered as promising carriers for encapsulating and delivering various biological active ingredients, however, there still have some issues about Zein-based drug delivery systems should be considered, including poor colloidal stability, low drug encapsulation efficiency as well as rapid initial drug release, and uncontrollable release. In this work, we reported for the first time that hyperbranched polymers (HPG) functionalized Zein with terminal alkyne (Zein-HPG-PA) can be used for loading anticancer agent curcumin (CUR) via a facile phenol-yne click reaction. The resultant product (Zein-HPG-PA@CUR) displays high drug loading capacity, small particle size and excellent water dispersibility. More importantly, almost no CUR was released from Zein-HPG-PA@CUR under pH7.4 and the cargo will be gradually released under acidic environment. As compared with free CUR, Zein-HPG-PA@CUR shows considerable cytotoxicity towards MDA-MB-231 cells under dark environment, while the cytotoxicity was significantly enhanced upon light-irradiation, implying great potential of Zein-HPG-PA@CUR for cancer treatment. Considered the above aspects, we believe that this work should be of significant impact on the biomedical applications of Zein, especially for fabrication of Zein-based responsive drug delivery systems.

A nanocarrier containing carboxylic and histamine groups with dual action: acetylcholine hydrolysis and antidote atropine delivery.

Disruption of cholinesterases and, as a consequence, increased levels of acetylcholine lead to serious disturbances in the functioning of the nervous system, including death. The need for rapid administration of an antidote to restore esterase activity is critical, but practical implementation of this is often difficult. One promising solution may be the development of antidote delivery systems that will release the drug only when acetylcholine levels are elevated. This approach will ensure timely delivery of the antidote and minimize side effects associated with uncontrolled drug release. Here, we describe the creation of a new smart system that serves as a carrier for delivering an antidote (i.e., atropine) and functions as a synthetic esterase to hydrolyze acetylcholine. The nanocarrier was synthesized through microemulsion polycondensation of phenylboronic acid with resorcinarenes containing hydroxy, imidazole, and carboxylic groups on the upper rim. The nanocarrier breaks down acetylcholine into choline and acetic acid. The latter acts on the boronate bonds, dissociating them. This leads to the destruction of the nanocarrier and the release of the antidote. The paper covers the creation of the nanocarrier, its physicochemical and biological properties, encapsulation of the antidote, acetylcholine hydrolysis, and antidote release.

Intelligent Microneedles Patch with Wireless Self‐Sensing and Anti‐Infective Actions

AbstractTraditional microneedle (MN) technology offers unique advantages in treating wound infections; however, its single‐function design lacks the capability for real‐time monitoring of wound conditions, often resulting in uncontrolled drug release. Herein, an anti‐infective and intelligent MN patch (SP‐CSMN) integrating three functional modules is developed, including temperature monitoring, Bluetooth wireless communication, and responsive drug release. The patch employed chitosan (CS) as a porous substrate, filled with temperature‐sensitive poly(N‐isopropylacrylamide) (PNIPAM) to encapsulate and release the antibiotic rifampicin. With the integrated sensing chip, SP‐CSMN enabled continuous temperature monitoring and real‐time feedback via smartphone Bluetooth communication. When the wound temperature exceeds 36.5 °C for 6 h, the system can automatically identify the infection occurrence and activate the heating module to trigger PNIPAM contraction, triggering rifampicin release. This self‐sensing and intelligent release cycles can repeat throughout its life‐cycle. The SP‐CSMN demonstrated precisely temperature‐induced drug release and enhanced antibacterial activities against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) in vitro. Furthermore, it sensitively monitored wound temperature changes in infected mice and significantly accelerated wound healing via controlled drug delivery. This advanced MN system offers a promising solution for efficient management of bacterial wound infections.

Cytokine Storm Syndromes: Immune Dysregulation in Severe Viral Infections and Autoimmune Diseases

Cytokine storm syndromes (CSS) are characterized by an excessive and uncontrolled release of pro-inflammatory cytokines, leading to systemic inflammation and multi-organ dysfunction. Initially recognized in severe viral infections, such as those caused by SARS-CoV-2 and H1N1, CSS have also been implicated in various autoimmune diseases, including systemic lupus erythematosus and rheumatoid arthritis. This review explores the pathophysiology of CSS, highlighting the critical roles of key cytokines such as interleukin-1 (IL-1), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) in driving hyper-inflammatory responses. We discuss the triggers of cytokine storms, including viral infections, autoimmune dysregulation, genetic predispositions, and therapeutic agents. Clinical manifestations can range from mild symptoms to severe complications, including acute respiratory distress syndrome (ARDS) and septic shock. Early recognition and intervention are vital for improving outcomes. Management strategies focus on mitigating inflammation through corticosteroids, monoclonal antibodies, and Janus kinase (JAK) inhibitors. As research advances, a deeper understanding of the mechanisms underlying cytokine storm syndromes will pave the way for innovative therapeutic approaches, enhancing patient care in these critical and complex conditions. Keywords: Cytokine Storm Syndromes (CSS), Pro-inflammatory Cytokines, SARS-CoV-2, Autoimmune Diseases, Acute Respiratory Distress Syndrome (ARDS), Therapeutic Strategies

CRL3ARMC5 ubiquitin ligase and Integrator phosphatase form parallel mechanisms to control early stages of RNA Pol II transcription.

Control of RNA polymerase II (RNA Pol II) through ubiquitylation is essential for the DNA-damage response. Here, we reveal a distinct ubiquitylation pathway in human cells, mediated by CRL3ARMC5, that targets excessive and defective RNA Pol II molecules at the initial stages of the transcription cycle. Upon ARMC5 loss, RNA Pol II accumulates in the free pool and in the promoter-proximal zone but is not permitted into elongation. We identify Integrator subunit 8 (INTS8) as a gatekeeper preventing the release of excess RNA Pol II molecules into gene bodies. Combined loss of ARMC5 and INTS8 has detrimental effects on cell growth and results in the uncontrolled release of excessive RNA Pol II complexes into early elongation, many of which are transcriptionally incompetent and fail to reach the ends of genes. These findings uncover CRL3ARMC5 and Integrator as two distinct pathways acting in parallel to monitor the quantity and quality of transcription complexes before they are licensed into elongation.

Sustainable Environmental Technologies: Recent Development, Opportunities, and Key Challenges

The ongoing increase in global population, industrialization, urbanization, and intensive agricultural practices has resulted in a wide range of environmental challenges including increased waste generation, rising greenhouse gas emissions, the uncontrolled release of emerging and toxic pollutants, degraded soil, water, and air quality, the depletion of natural resources, and the escalating impact of climate change [...]

Serum Gel Formulation of Mundu Fruit Extract (Garcinia dulcis (Roxb.) Kurz) as Antioxidant and Anti-elastase

UV radiation can generate ROS, thereby damaging neutrophils, leading to the uncontrolled release of elastase, and causing aging. This study intends to examine the antioxidants and anti-elastase activity of the skin of Garcinia dulcis (Roxb.) Kurz fruit in serum gel extract preparation. The methods used in this research are microwave-assisted extraction and antioxidants using the ABTS (2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) method. Three formulas were made with 100 x IC50, 200 x IC50, and 300 x IC50. The test results for the three formulas showed the best antioxidant and anti-elastase activity values in formula 3, with IC50 values ​​of 66.26 ppm and 111.48 ppm. This indicates that the higher the extract concentration in the formulation provides better activity in the serum gel preparation. In the third formulation, evaluation observations were made on the preparation, and a pH value close to the skin’s pH was produced, namely in formula 3. Therefore, it can be concluded that the Mundu fruit peel extract has antioxidant and anti-elastase activity. The extract is applied to cosmetic preparations and still provides good antioxidant and anti-elastase activity results.

Reimagining anti-inflammatory drugs delivery: the integration of ordered mesoporous silica and MOF materials for enhanced therapeutic outcomes

Abstract Migraine, one of the neurological conditions, affects approximately 15% of the global population. It is characterized by intense headaches accompanied by nausea, vomiting, and heightened sensitivity to light. The first line of drugs for treating migraine are non-steroidal anti-inflammatory drugs. Unfortunately, these medications suffer from poor solubility in water, uncontrolled release, and numerous adverse side effects. In order to maximize their therapeutic effect by preventing premature release and degradation, novel drug delivery systems based on composites are being dynamically developed. Herein, the biocompatible ketoprofen (K), naproxen sodium (NS), and diclofenac sodium (DS) vehicles integrating ordered mesoporous silica (SBA-16) with Fe-based metal–organic frameworks (MIL-101(Fe)) were synthesized via the solvothermal method. The composites were characterized by different percentages of MIL-101(Fe) (25 and 50 wt.%), which had a significant impact on their porosity, structure, and number of functional groups. The SBA-16@MIL-101(Fe)-25 and SBA-16@MIL-101(Fe)-50 samples exhibited BET surface areas of 768 and 324 m2 g−1, respectively. Their sorption capacities towards selected anti-inflammatory drugs were in the range of 141–318 mg g−1 for K, 481–490 mg g−1 for NS, and 246–589 mg g−1 for DS, notably exceeding the values obtained for pure mesoporous silica (5–9 mg g−1). Morphological defects and specific functional groups, derived from SBA-16 and MIL-101(Fe), contributed to generating new adsorption sites in composites, enhancing host-guest interactions. The drug release profiles were determined by the carrier porosity, surface charge, and the presence of functional groups. The diffusion of K and DS from the composites into the phosphate buffer (pH 7.7), mimicking rectal fluid, occurred in a more controlled manner compared to pristine silica. The SBA-16@MIL-101(Fe)-50 carrier released 82% of K and 90% of DS over 24 h.

Self-Exfoliated Guanidinium Covalent Organic Nanosheets as High-Capacity Curcumin Carrier.

Drug administration is commonly used to treat chronic wounds but faces challenges such as poor bioavailability, instability, and uncontrollable release. Existing drug delivery platforms are limited by chemical instability, poor functionality, complex synthesis, and toxic by-products. Presently, research efforts are focused on developing novel drug carriers to enhance drug efficacy. Guanidinium Covalent Organic Nanosheets (gCONs) offer promising alternatives due to their high porosity, surface area, loading capacity, and ability to provide controlled, sustained, and target-specific drug delivery. Herein, we successfully synthesized self-exfoliated gCONs using a Schiff base condensation reaction and embedded curcumin (CUR), a polyphenolic pleiotropic drug with antioxidant and anti-inflammatory properties, via the wet impregnation method. The BET porosimeter exhibited the filling of gCON pores with CUR. Morphological investigations revealed the formation of sheet-like structures in gCON. Culturing human dermal fibroblasts (hDFs) on gCON demonstrated cytocompatibility even at a concentration as high as 1000 µg/mL. Drug release studies demonstrated a controlled and sustained release of CUR over an extended period of 5 days, facilitated by the high loading capacity of gCON. Furthermore, the inherent antioxidant and anti-inflammatory properties of CUR were preserved after loading into the gCON, underscoring the potential of CUR-loaded gCON formulation for effective therapeutic applications. Conclusively, this study provides fundamental information relevant to the performance of gCONs as a drug delivery system and the synergistic effect of CUR and CONs addressing issues like drug bioavailability and instability.

Dynamic-Covalent Mesoporous Silica Nanohybrid with pH/ROS-Responsive Drug Release for Targeted Tumor Therapy.

Nanomedicine provides promising new methodologies for the treatment of tumors but still faces several limitations, including poor colloidal stability, uncontrollable drug release, and insufficient drug targeting. Herein, hyaluronic acid (HA) was used to modify the surface of mesoporous silica nanoparticles (MSNs) via a dynamic-covalent linker, phenylborate ester (PBAE), termed MA. The HA modifier provided enhanced colloidal stability to the hybrid nanoparticles. As expected, MA exhibited an improved biocompatibility and high potential for biomedical applications. Moreover, MA with a negatively charged surface effectively adsorbed the drug Doxorubicin (DOX) inside the carriers, ensuring minimal drug leakage. In an acidic and reactive oxygen species (ROS)-containing condition mimicking the tumor microenvironment, MA@DOX (MAD) continuously released its payloads, likely due to the cleavage of the pH/ROS-sensitive PBAE. Compared with free DOX, MAD had 2.2 times higher accessibility to tumor cells than free DOX. The favorable stability and cancer-selective drug release make this nanoformulation a promising platform for potent cancer treatment.

MATHEMATICAL MODELLING AN ACTIVE COMPONENT RELEASE FROM SWELLING POLYMER-COATED GRANULE

A mathematical model of an active component release from swelling polymer-coated granule is proposed. The model predicts the degree of an active component release and the size of the capsule at any given time. The model is based on two differential equations of molecular diffusion with corresponding boundary conditions. The first equation describes the transfer of water through the polymer coating layer into the capsule. The second equation characterizes the diffusion of an active component through the coating layer into the environment. The boundary conditions vary depending on the release process period: impregnation of the coating layer with water, dissolution of the fertiliser solid core surrounded by a saturated solution and a decrease in the concentration of the solution inside the capsule after the total dissolution of the solid core. Unlike well-known models, this model takes into account the dependence of the release rate of an active component on the moisture content of the coating layer. Additional relationships allow to calculate the current volume and radius of the capsule, pressure and tensile stress inside the shell. The model also makes it possible to predict the onset of uncontrolled release of an active component when the critical value of the tensile stress and rupture of the shell is reached. Urea granules with an acrylic polymer elastic coating were obtained in a spouted bed laboratory apparatus in order to verify the adequacy of the mathematical model. Urea release experiment was carried out in water under static conditions. The dependences of the degree of urea release and the radius of granules on the process time are obtained. Comparison of the calculated and experimental data showed their good agreement. The standard deviation for the degree of urea release was 0.011 and for the granule radius it was 0.027 mm. For citation: Lipin A.A., Lipin A.G. Mathematical modelling an active component release from swelling polymer-coated granule. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 11. P. 138-144. DOI: 10.6060/ivkkt.20246711.7058.

The Impact of the Configuration of a Hydrogen Refueling Station on Risk Level

The paper discusses potential hazards at hydrogen refueling stations for transportation vehicles: cars and trucks. The main hazard analyzed here is an uncontrolled gas release due to a failure in one of the structures in the station: storage tanks of different pressure levels or a dispenser. This may lead to a hydrogen cloud occurring near the source of the release or at a given distance. The range of the cloud was analyzed in connection to the amount of the released gas and the wind velocity. The results of the calculations were compared for chosen structures in the station. Then potential fires and explosions were investigated. The hazard zones were calculated with respect to heat fluxes generated in the fires and the overpressure generated in explosions. The maximum ranges of these zones vary from about 14 to 30 m and from about 9 to 14 m for a fires and an explosions of hydrogen, respectively. Finally, human death probabilities are presented as functions of the distance from the sources of the uncontrolled hydrogen releases. These are shown for different amounts and pressures of the released gas. In addition, the risk of human death is determined along with the area, where it reaches the highest value in the whole station. The risk of human death in this area is 1.63 × 10−5 [1/year]. The area is approximately 8 square meters.

Heat mitigation in basal compacted clay liners in municipal solid waste landfills.

In municipal solid waste (MSW) landfills, biodegradation of the organic MSW fraction results in elevated waste and basal liner temperatures which have the potential to cause the clay component of the basal liner to experience severe moisture loss over time and eventually undergo desiccation cracking. Cracking of the basal liner's clay component would result in an uncontrolled release of contaminants into the surrounding environment and ultimately give rise to a variety of major environmental concerns. Accordingly, this study examined the variation of temperature-moisture profiles along the depth of a compacted clay liner (CCL) exposed to different constant elevated waste temperatures (CETs) in the absence and presence of two heat reduction techniques, respectively. Rockwool insulation layers with varying thicknesses and galvanized steel cooling pipes with varying flowrates were introduced separately as the two heat reduction techniques. Introduction of both techniques led to a significant attenuation of the temperature rise and desiccation experienced by the CCL in the face of different CETs. An increase in rockwool thickness increments led to a progressive reduction of CCL temperature, while an increase in flow rate under turbulent condition did not have a significant influence on the temperature and desiccation reduction of the CCL. Nevertheless, the present study certainly highlights the potential of the two proposed heat reduction techniques to minimize desiccation and consequently increase the service life of CCLs exposed to different elevated temperatures in MSW landfills.

Mechanism and kinetic study of n-undecane degradation on Co-CeO2: A dual approach combining thermal and plasma catalysis

The catalytic degradation of long-chain alkanes presents a formidable challenge in environmental chemistry. n-Undecane (C11), a quintessential long-chain alkane, predominates as a component of volatile organic compounds (VOCs) emitted from the printing industry and diesel-powered vehicles. The uncontrolled release of these compounds into the atmosphere necessitates stringent measures. This study reports on the plasma-catalytic degradation of n-undecane over the CeO2 based catalysts cooperated with cobalt (Co), manganese (Mn), aluminum (Al), nickel (Ni), iron (Fe), or magnesium (Mg) via aerosol pyrolysis method. Notably, the Co-doped CeO2 catalyst with a Co:Ce atom ratio of 4:1, in conjunction with plasma, achieves an optimal degradation performance. Under the reaction conditions of 90 °C and an energy density of 40 J/L, C11 conversion and COx selectivity reached impressive levels of 100 % and 97 %, respectively. Characterization findings indicate that elevated ratios of Ce3+/(Ce3++Ce4+) and Co3+/(Co2++Co3+) are conducive to the catalytic degradation of C11. A kinetic model has been developed to elucidate the thermal and plasma catalytic degradation mechanisms.