Chemical Damage Research Articles

Effect of Five Different Antioxidants on the Effectiveness of Goat Semen Cryopreservation.

The effective combination of semen cryopreservation and artificial insemination has a positive effect on the conservation of germplasm resources, production and breeding, etc. However, during the process of semen cryopreservation, the sperm cells are very susceptible to different degrees of physical, chemical, and oxidative stress damage. Oxidative damage is the most important factor that reduces semen quality, which is affected by factors such as dilution equilibrium, change of osmotic pressure, cold shock, and enzyme action during the freezing-thawing process, which results in the aggregation of a large amount of reactive oxygen species (ROS) in sperm cells and affects the quality of semen after thawing. Therefore, the method of adding antioxidants to semen cryoprotective diluent is usually used to improve the effect of semen cryopreservation. The aim of this experiment was to investigate the effects of adding five antioxidants (GLP, Mito Q, NAC, SLS, and SDS) to semen cryoprotection diluent on the cryopreservation effect of semen from Saanen dairy goats. The optimal preservation concentrations were screened by detecting sperm viability, plasma membrane integrity, antioxidant capacity, and acrosomal enzyme activities after thawing, and the experimental results were as follows: the optimal concentrations of GLP, Mito Q, NAC, SLS, and SDS added to semen cryopreservation diluent at different concentrations were 0.8mg/mL, 150nmol/L, 0.6mg/mL, 0.15mg/ mL, 0.6mg/mL, and 0.15mg/mL. The optimal concentrations of the five antioxidants were added to the diluent and analyzed after 1week of cryopreservation, and it was found that sperm viability, plasma membrane integrity, and mitochondrial activity were significantly enhanced after thawing compared with the control group (P < 0.05), and their antioxidant capacity was significantly enhanced (P < 0.05). Therefore, the addition of the above five antioxidants to goat sperm cryodilution solution had a better enhancement of sperm cryopreservation. This study provides a useful reference for exploring the improvement of goat semen cryoprotection effect.

Regulated Cell Death in Endometriosis.

Regulated cell death (RCD) represents a distinct mode of cell demise, differing from accidental cell death (ACD), characterized by specific signaling cascades orchestrated by diverse biomolecules. The regular process of cell death plays a crucial role in upholding internal homeostasis, acting as a safeguard against biological or chemical damage. Nonetheless, specific programmed cell deaths have the potential to activate an immune-inflammatory response, potentially contributing to diseases by enlisting immune cells and releasing pro-inflammatory factors. Endometriosis, a prevalent gynecological ailment, remains incompletely understood despite substantial progress in unraveling associated signaling pathways. Its complexity is intricately tied to the dysregulation of inflammatory immune responses, with various RCD processes such as apoptosis, autophagic cell death, pyroptosis, and ferroptosis implicated in its development. Notably, limited research explores the association between endometriosis and specific RCD pathways like pyroptosis and cuproptosis. The exploration of regulated cell death in the context of endometriosis holds tremendous potential for further advancements. This article thoroughly reviews the molecular mechanisms governed by regulated cell death and their implications for endometriosis. A comprehensive understanding of the regulated cell death mechanism in endometriosis has the potential to catalyze the development of promising therapeutic strategies and chart the course for future research directions in the field.

Femtosecond laser ablation (fs-LA) XPS – A novel XPS depth profiling technique for thin films, coatings and multi-layered structures

Sputter depth profiling has been employed for XPS/AESdepth profilingsincethe late 1960s. However, for many materials, ion beam induced damage distorts the chemical state information and chemical composition, limiting the value of the analysis. A novelmethodology is presented in which XPS depth profiles are generated using a 160 fs pulse length, 1030 nm peak wavelength femtosecond laser in place of the traditional ion gun. Femtosecond laser ablation (fs-LA) XPS depth profiles are compared with argon monatomic and cluster ion beam depth profilesfor different classes of materials, including ceramics, semiconductors, polymers and metals. In all cases, the XPS spectra recorded following femtosecond laser ablation are fully representative of the original chemical composition and chemical state, with no ablation induced damage. The technique is also shown to be very versatile with ablation rates of <20 nm per pulse being achieved for thin films but profiles to depths of >30 μm are also realisable in practical time scales.fs-LA XPS depth profiling promises to be a very exciting new methodology for the XPS community, complementing sputter depth profiling but avoiding the chemical damage induced by ion beams and offering valuable new depth profiling capabilities.

Characterization of the mechanical properties of the cortex region of human hair fibers by multiparametric atomic force microscopy mapping

We show the benefit of the use of atomic force microscopy (AFM) in spectroscopy force mode (FV: force volume) for evaluation of the cosmetic active effectiveness in improving the mechanical properties of human hair fibers cortex region. For this, we characterized human hair fibers without and with chemical damage caused by bleaching process. Fiber and resin (embedding material) data were obtained simultaneously in the mapping in order to have the resin data as a reference to ensure a coherent comparison between data from the different fiber groups. Our AFM results, which were evaluated using statistical tests, demonstrated the degradation of fibers after bleaching, corroborating the findings of transmission electron microscopy analysis and the effectiveness of a cosmetic active ingredient in improving the Young's modulus (elastic modulus) (E) of the damaged fibers. We also found a radial decrease in the natural logarithm of Young's modulus ln(E) along the cross-section of the active group fiber, which is compatible with confocal Raman spectroscopy analysis by other authors, demonstrating variation of the active permeation with depth. We note that Young's modulus was also determined by a tensile tester (macro-scale technique), in which it was not possible to obtain statistically significant differences between the groups, evidencing the advantage of the FV-AFM analysis. We also found an increase in ln(E) accompanied by a decrease in maximum adhesion force between tip and sample (negative Pearson correlation coefficient). This result can be explained by the fact that structures composed of hydrophobic components have a higher Young's modulus than structures composed of hydrophilic components.•Bleaching damage and cosmetic hair treatment assessed by AFM, TEM, and tensile tester.•Young's modulus by AFM nanoindentation of hair fibers monitored by sample standard.•Young's modulus changes radially along the cross-section due to the cosmetic active.•AFM data show statistically significant differences among sample groups.•Tensile tester was not able to show statistically significant differences.

Self-reporting and Biodegradable Thermosetting Solid Polymer Electrolyte.

To date, significant efforts have been dedicated to improve their ionic conductivity, thermal stability, and mechanical strength of solid polymer electrolytes (SPEs). However, direct monitoring of physical and chemical changes in SPEs is still lacking. Moreover, existing thermosetting SPEs are hardly degradable. Herein, by overcoming the limitation predicted by Flory theory, self-reporting and biodegradable thermosetting hyperbranched poly(β-amino ester)-based SPEs (HPAE-SPEs) are reported. HPAE is successfully synthesized through a well-controlled "A2+B4" Michael addition strategy and then crosslinked it in situ to produce HPAE-SPEs. The multiple tertiary aliphatic amines at the branching sites confer multicolour luminescence to HPAE-SPEs, enabling direct observation of its physical and chemical damage. After use, HPAE-SPEs can be rapidly hydrolysed into non-hazardous β-amino acids and polyols via self-catalysis. Optimized HPAE-SPE exhibits an ionic conductivity of 1.3×10-4 S/cm at 60 °C, a Na+ transference number ( ) of 0.67, a highly stable sodium plating-stripping behaviour and a low overpotential of ≈190 mV. This study establishes a new paradigm for developing SPEs by engineering multifunctional polymers. The self-reporting and biodegradable properties would greatly expand the scope of applications for SPEs.

Self‐reporting and Biodegradable Thermosetting Solid Polymer Electrolyte

AbstractTo date, significant efforts have been dedicated to improve their ionic conductivity, thermal stability, and mechanical strength of solid polymer electrolytes (SPEs). However, direct monitoring of physical and chemical changes in SPEs is still lacking. Moreover, existing thermosetting SPEs are hardly degradable. Herein, by overcoming the limitation predicted by Flory theory, self‐reporting and biodegradable thermosetting hyperbranched poly(β‐amino ester)‐based SPEs (HPAE‐SPEs) are reported. HPAE is successfully synthesized through a well‐controlled “A2+B4” Michael addition strategy and then crosslinked it in situ to produce HPAE‐SPEs. The multiple tertiary aliphatic amines at the branching sites confer multicolour luminescence to HPAE‐SPEs, enabling direct observation of its physical and chemical damage. After use, HPAE‐SPEs can be rapidly hydrolysed into non‐hazardous β‐amino acids and polyols via self‐catalysis. Optimized HPAE‐SPE exhibits an ionic conductivity of 1.3×10−4 S/cm at 60 °C, a Na+ transference number ( ) of 0.67, a highly stable sodium plating‐stripping behaviour and a low overpotential of ≈190 mV. This study establishes a new paradigm for developing SPEs by engineering multifunctional polymers. The self‐reporting and biodegradable properties would greatly expand the scope of applications for SPEs.

Xanthohumol, a prenylated flavonoid from hops (Humulus lupulus L.) exerts multidirectional pro-healing properties towards damaged zebrafish hair cells by regulating the innate immune response

Xanthohumol (XN) is a prominent prenylated flavonoid present in the hop plant (Humulus lupulus L.). Despite undoubted pro-healing properties of hop plant, there is still a need for clinical investigations confirming these effects as well as the underlying molecular mechanisms. The present study was designed to (1) establish the role of XN in non-invasive inflammation induced by chemical damage to zebrafish hair cells, (2) clarify if it influences cell injury severity, neutrophil migration, macrophage activation, cell regeneration, and (3) find out whether it modulates the gene expression profile of chosen immune and stress response markers. All experiments were performed on 3 dpf zebrafish larvae. After fertilization the embryos were transferred to appropriate XN solutions (0.1 μM, 0.3 μM and 0.5 μM). The 40 min 10 μM CuSO4 exposure evoked severe damage to posterior lateral line hair cells triggering a robust acute inflammatory response. Four readouts were selected as the indicators of XN role in the process of inflammation: 1) hair cell death, 2) neutrophil migration towards damaged hair cells, 3) macrophage activation and recruitment to damaged hair cells, 4) hair cell regeneration. The assessments involved in vivo confocal microscopy imaging and qPCR based molecular analysis. It was demonstrated that XN (1) influences death pathway of damaged hair cells by redirecting their severe necrotic phenotype into apoptotic one, (2) impacts the immune response via regulating neutrophil migration, macrophage recruitment and activation (3) modulates gene expression of immune system markers and (4) accelerates hair cell regeneration.

Evidence of internalized microplastics in mussel tissues detected by volumetric Raman imaging

Microplastics are a global ecological concern due to their potential risk to wildlife and human health. Animals ingest microplastics, which can enter the trophic chain and ultimately impact human well-being. The ingestion of microplastics can cause physical and chemical damage to the animals' digestive systems, affecting their health. To estimate the risk to ecosystems and human health, it is crucial to understand the accumulation and localization of ingested microplastics within the cells and tissues of living organisms. However, analyzing this issue is challenging due to the risk of sample contamination, given the ubiquity of microplastics. Here, an analytical approach is employed to confirm the internalization of microplastics in cryogenic cross-sections of mussel tissue. Using 3D Raman confocal microscopy in combination with chemometrics, microplastics measuring 1 μm in size were detected. The results were further validated using optical and fluorescence microscopy. The findings revealed evidence of microplastics being internalized in the digestive epithelial tissues of exposed mussels (Mytilus galloprovincialis), specifically within the digestive cells forming digestive alveoli. This study highlights the need to investigate the internalization of microplastics in organisms like mussels, as it helps us understand the potential risks they pose to aquatic biota and ultimately to human health. By employing advanced imaging techniques, challenges associated with sample contamination can be overcome and valuable insights into the impact of microplastics on marine ecosystems and human consumers are provided.

A systematically evolved method for the effective use of essential oil blends for the structural maintenance of palm leaf manuscripts

Palm leaf manuscripts (PLMs) are traditional carriers that contain a wealth of knowledge from different disciplines written by ancient scholars. However, PLMs are susceptible to deterioration due to moisture, light, fungi and bacteria. An existing method of applying essential oils (EOs) to preserve PLMs does not currently appear successful, hence the study presented here which aimed to maximise the preservation characteristics of six different EO blends, prepared and applied to palm leaves, which were then tested for stiffness, brightness and weight gain. The interpretation of the efficiency of EO blends in the preservation of PLMs is attributed to the compatibility between the oils due to the various constituents present in the individual EOs. FTIR spectroscopy was used to understand the compatibility of the oils in a blend and any EO blend rendering a higher stiffness and brightness was identified as having a high preservation performance. Based on the investigation, good compatibility is observed between the FTIR spectrum of Blend-E with its contributing EOs of citronella, neem and mustard. On the other hand, Blend-B exhibits poor preservation characteristics and incompatibility. The study concludes with the recommendation that Blend-E is suitable for the treatment and regular maintenance of PLMs as it can help reduce physical and chemical damage.

Etiology of gingival recession - a literature review.

Gum recession is a common problem that in most cases does not cause any bothersome symptoms to the patient. They can affect people of any age and are most often diagnosed on the vestibular surfaces of the teeth. They are manifested by the exposure of part of the root through the apical migration of the gingival margin. Its etiology is not fully understood, but it is known that it consists of many factors. The authors discussed such factors as inflammation, gum biotype, patient's age, mechanical and chemical damage, smoking, presence of tartar, cervical defects and their reconstruction, orthodontic treatment, occlusal overload and iatrogenic factors. Additionally, important risk factors also include genetic predispositions and abnormalities in the immune system. In addition, certain hygiene habits, such as improper brushing techniques or lack of regular check-ups at the dentist, may also contribute to the development of gum recession. Understanding the comprehensive nature of these factors is crucial to the effective treatment and prevention of this common condition. It is also worth taking into account the importance of educating patients on proper oral hygiene and regular dental check-ups to prevent gum recession.

&lt;b&gt;Neurotoxic effects of type II-diabetes mellitus and the possible preventive effects of olive leaves supplement in male rats&lt;/b&gt;

Background: Diabetes mellitus (DM) is a common metabolic disorder with well-known serious secondary complications. It is also associated with central nervous system damage. This damage is characterized by impairments in brain functions, with neurochemical and structural abnormalities. Aim: The study was conducted to clarify the neuroprotective effects of olive leaves supplement on brain and brain histological structure of diabetic adult rats. Methods: Thirty adult male rats were allocated into three groups, The first group (CC), received an oral supplement containing olive leaves (OLS) and served as a control; another group (DM), diabetes mellitus was induced in these animals and left for 40 days; and the third group was DM+OL, which induced diabetes mellitus, then treated with oral (OLS) for 40 days. The investigation included serum glycemic index measurements, in addition, the level of malondialdehyde (MDA), glutathione (GSH), dopamine (DOP), acetylcholinesterase (AchE) in brain tissue, and histopathology of brain and pancreas. Results: We demonstrated a significant increase in glycemic index measurements in diabetic groups (DM, DM+OL) at the beginning of a trial, however, the same parameters were significantly decreased after treatment with OLS in only DM+OL group after 40 days. Study also showed differences in the levels of malondialdehyde (MDA), and glutathione (GSH), in the diabetic groups, which returned to normal levels after being treated with OLS. Moreover, acetylcholinesterase (AchE), and dopamine (DOP) exhibited a significant decline in diabetic rats. However, OLS induced a considerable rise in these neurotransmitters after treatment with it in DM+OL group. The histopathological section of the pancreas and brain showed histopathological changes in (DM) groups, whereas, the tissue was shielded from chemical damage from DM by the (OLS) treatment in DM+OL animals. Conclusion: Overall, diabetes impairs glucose hemostasis by affecting glucose concentration, insulin level, and insulin resistance, However, olive leaves supplement restored the glucose hemostasis close to the normal in diabetic rats. Furthermore, diabetes affected neurotransmitters by increasing the level of oxidative stress in brain tissue, and brain cell damage. Nevertheless, olive leave supplements can ameliorate diabetes mellitus harmful effects by retrieving normal oxidative environment in brain.

A gravity–inspired design for robust and photothermal superhydrophobic coating with dual–size lignin micro–nanospheres

The use of renewable materials as structural components for constructing superhydrophobic coatings is an important direction for future development. Here, a robust and photothermal superhydrophobic coating (with a water contact angle of 166.1 ± 0.8° and a sliding angle of 2.8 ± 0.1°) is fabricated using dual–size lignin micro–nanospheres (LMNSs), comprising lignin microspheres (m–LMNSs) and nanospheres (n–LMNSs), which successively settle on the substrate surface under the effect of gravity. The microstructure armor formed by the combination of m–LMNSs and epoxy resin endows the coating with excellent abrasion resistance and bonding strength. Moreover, the presence of n–LMNSs within the cavities provides water repellency. The coating maintains superhydrophobicity even after the abrasion distance exceeds 320 cm or after 210 tape peeling cycles. The coating also exhibits robustness under various forms of mechanical and chemical damage. Furthermore, the photothermal effect of the coating enables rapid heating of its surface temperature from ∼13 to 112 °C in only 60 s under laser irradiation. This innovative structural regulation approach enhances the durability and photothermal performance of lignin–based superhydrophobic coatings, demonstrating the practical applicability of the approach.

Mechanically robust, self-reporting and healable polyurethane elastomers by incorporating symmetric/asymmetric chain extenders.

Self-healing elastomers usually show poor mechanical properties and environmental stability, and they cannot self-report mechanical/chemical damage. Herein, an innovative design strategy is reported that combines symmetric/asymmetric chain extenders to create large yet disordered hard domains within polyurethane (PU) elastomers, enabling the integration of mechanical robustness and self-reporting and self-healing capabilities to overcome both mechanical and chemical damage. Specifically, large yet disordered hard domains were created by governing the molar contents of asymmetric fluorescent 2-(4-aminophenyl)-5-aminobenzimidazole (PABZ) and symmetric 4-aminophenyl disulfide (APDS). Such a structural feature led to a small free-volume fraction, prominent strain-induced crystallization (SIC), and high energy of dissipation, enabling the PU elastomer to display outstanding mechanical strength (60.7 MPa) and toughness (177.9 MJ m-3). Meanwhile, the loose stacking of disordered hard domains imposed small restriction on network chains and imparted the network with high relaxation dynamics, leading to high healing efficiency (97.8%). More importantly, the fluorescence intensity was stimulus-responsive and thus the PU elastomer could self-report mechanical/chemical damage and healing processes. The PU elastomer also showed potential application prospects in information encoding and encryption. Furthermore, selecting polydimethylsiloxane as one of the soft segments could effectively endow the PU elastomer with intrinsic hydrophobicity. Therefore, this work provides valuable guidance for designing multi-functional materials with anti-counterfeiting, self-reporting, and healing properties as well as high mechanical properties and hydrophobicity.

The ability of bacteria from legume plant roots grown on former coal mining soil to produce Indole-3-Acetic Acid (IAA)

In general, coal mining is carried out openly using heavy equipment to take and move soil in the topsoil area until coal mining is possible to be conducted. As a consequence, the nutrient level is low because there is physical, chemical, and biological soil damage. Bioremediation is one of the alternatives to improve former coal mining land by utilizing soil microorganisms that have a role in soil plant hormone levels, such as auxin-produced root rhizosphere bacteria. This study aimed to isolate and characterize rhizosphere bacteria of legume plant roots grown on former coal mining soil, and to determine qualitatively and quantitatively its ability to produce IAA hormones. The characterizations include gram properties, colony morphology, arrangement of isolate, and cell shape. Then, the bacterial ability to produce IAA qualitatively and quantitatively respectively using the Salkowski method and spectrophotometry were tested. The results revealed that there were eleven isolates of legume plant root rhizosphere bacteria grown on the former coal mining soil that were able to produce IAA hormones with an average concentration of 15.949 ppm (2IA4); 10.762 ppm (4IIE3); 9.700 ppm (ID3); 9.422 ppm (3IB4); 7.970 ppm (2IA3); 7.847 ppm (6IIB3); 7.268 ppm (8IIIB4); 6.804 ppm (IIID5); 6.459 ppm (IE5); 5.379 ppm (7IIIB3); and 5.086 ppm (5IB3). Isolates of rhizosphere bacteria with the highest concentration have the potential to be chosen as a growth booster for legume plants grown on former coal mining soil to increase legume crop productivity.

Analysis of Physcho-Chemical Changes and Mechanical Damage of Tomato (Licopersicum Esculentum L.) During the Transportation

Quality analysis on tomatoes must always be done to maintain the shelf life and physical, chemical and mechanical damage of a product. However, generally the initial damage to tomatoes occurs in the post-harvest handling process during the transportation of tomatoes for distribution to marketing areas. Damage often occurs due to the distribution process with improper selection of packaging containers. This study aims to analyze the physical, chemical and mechanical changes due to the transportation process of various types of packaging during the distribution of tomato fruit so that it can be known which type of packaging container is able to maintain the quality of tomato fruit during the distribution process. This research method uses three treatments, namely tomatoes packed in plastic bags, wooden boxes and styrofoam during the transportation process. Data analysis was carried out by measuring parameters, namely weight loss, color, percentage of defects and total soluble solids. Based on the research that has been done, it can be concluded that the type of wooden box packaging has the most changes in weight shrinkage, mechanical damage, and Total Soluble Solid (TSS) and styrofoam packaging can minimize the occurrence of weight shrinkage, mechanical damage and Total Soluble Solid (TSS).

How Do Thermophiles Organize Their Genomes?

All cells must maintain the structural and functional integrity of the genome under a wide range of environments. High temperatures pose a formidable challenge to cells by denaturing the DNA double helix, causing chemical damage to DNA, and increasing the random thermal motion of chromosomes. Thermophiles, predominantly classified as bacteria or archaea, exhibit an exceptional capacity to mitigate these detrimental effects and prosper under extreme thermal conditions, with some species tolerating temperatures higher than 100°C. Their genomes are mainly characterized by the presence of reverse gyrase, a unique topoisomerase that introduces positive supercoils into DNA. This enzyme has been suggested to maintain the genome integrity of thermophiles by limiting DNA melting and mediating DNA repair. Previous studies provided significant insights into the mechanisms by which NAPs, histones, SMC superfamily proteins, and polyamines affect the 3D genomes of thermophiles across different scales. Here, I discuss current knowledge of the genome organization in thermophiles and pertinent research questions for future investigations.

Colorimetria e propriedades químicas da madeira de Parkia pendula e Simarouba amara modificada termicamente

ABSTRACT The thermal modification of wood is a process that alters its chemical composition, aiming to improve technological properties such as dimensional stability, reduction of equilibrium moisture content, homogeneity, or color. In this context, this study aimed to evaluate the colorimetry and chemical properties of the wood of Parkia pendula (angelim-saia) and Simarouba amara (marupá) that was thermally modified by different methods. Three treatments were evaluated: T1 (pre-treatment in an oven for one hour at 120 °C and treatment in an oven at 180 °C for three hours); T2 (pre-treatment in an autoclave at 125 °C for three hours under 1.2 kgf cm-2 and treatment in an oven at 180 °C for three hours); and T3 (without pre-treatment, with sample treatment in vegetable oil). The thermally modified wood was evaluated in relation to untreated wood for structural chemical composition (extractives, lignin, holocellulose and ash content), colorimetric parameters defined through the CIELAB (Commission Internationale de l´Eclairage) system and total color variation. We detected a significant increase in extractives content and a decrease in holocellulose and lignin content in T3 for both species, which can be explained by the impregnation of oil in the wood samples. The thermal modification caused the surface darkening of the wood of both species, which was more pronounced in P. pendula. Despite the colorimetric change, there was no chemical damage to the wood.

Design of a stable wearable piezoresistive sensor with a laminated pattern for simultaneous anti-wetting and self-power

Wearable piezoresistive sensors have great potential in motion monitoring, health detection, and virtual reality. However, such sensors have difficulty maintaining long-term and stable sensing performance in complicated conditions such as wetting, corrosion and without external power supply. Herein, we integrated a stable wearable piezoresistance sensor (SWPS) with sandwich-like laminated structure, which consists of a flexible superhydrophobic conductive material, a rigid superhydrophobic material, conductive coil and magnetic composite materials which is used to provide magnetic field. SWPS achieves simultaneously effective pressure sensing and self-power supply. Importantly, such sensor maintains outstanding superhydrophobicity even when exposed to mechanical or chemical damage, such as cyclic compression, impact and wetting erosion, ensuring the reliable and long-lasting sensing performance. Our design strategy could also guide the development of other wearable sensor materials that need to retain long-term sensing performance in harsh operating conditions.

Macro-micro crack and damage evolution characteristics of concrete: After the action of acidic drying-saturation cycle

Repeated saturation and drying of acidic mine water have a major influence on the mechanical properties and stability monitoring of artificial dams (concrete walls) in underground reservoirs. A uniaxial compression acoustic emission (AE) monitoring test was conducted to quantify the evolution characteristics of micro cracks in concrete. In addition, the evolution characteristics of macro cracks during sample failure were quantitatively analyzed by fractal dimension theory and Image-Pro. Finally, the damage constitutive model was established and the damage evolution law was studied. The results of the study showed that the percentage of micro shear cracks in dry samples exhibited a decreasing and then increasing trend during the loading stage before the uniaxial compressive strength (UCS). However, after the acidic drying-saturation cycle (ADSC), this percentage of concrete showed an increasing trend. As the number of drying-saturation cycles increases or the pH decreases, the fractal dimension, total length, and area of the macro cracks also increase. The damage constitutive model, based on ADSC and loading conditions, works well. After the ADSC, the concrete sample will have three damage stages. Additionally, the strain at entry into each stage increases. Expansion and shrinkage of hydration products and chemical damage due to ion exchange are the mechanisms that change the mechanical properties and the macro-micro crack evolution pattern of concrete after ADSC.

A Review on Barrier Properties of Cellulose/Clay Nanocomposite Polymers for Packaging Applications.

Packaging materials are used to protect consumer goods, such as food, drinks, cosmetics, healthcare items, and more, from harmful gases and physical and chemical damage during storage, distribution, and handling. Synthetic plastics are commonly used because they exhibit sufficient characteristics for packaging requirements, but their end lives result in environmental pollution, the depletion of landfill space, rising sea pollution, and more. These exist because of their poor biodegradability, limited recyclability, etc. There has been an increasing demand for replacing these polymers with bio-based biodegradable materials for a sustainable environment. Cellulosic nanomaterials have been proposed as a potential substitute in the preparation of packaging films. Nevertheless, their application is limited due to their poor properties, such as their barrier, thermal, and mechanical properties, to name a few. The barrier properties of materials play a pivotal role in extending and determining the shelf lives of packaged foods. Nanofillers have been used to enhance the barrier properties. This article reviews the literature on the barrier properties of cellulose/clay nanocomposite polymers. Cellulose extraction stages such as pretreatment, bleaching, and nanoparticle isolation are outlined, followed by cellulose modification methods. Finally, a brief discussion on nanofillers is provided, followed by an extensive literature review on the barrier properties of cellulose/clay nanocomposite polymers. Although similar reviews have been presented, the use of modification processes applied to cellulose, clay, and final nanocomposites to enhance the barrier properties has not been reviewed. Therefore, this article focuses on this scope.