Plasticizing Effect Research Articles

Early‐life and chronic exposure to high‐fat diet alters noradrenergic and glutamatergic neurotransmission in the male rat amygdala and hippocampus under cognitive challenges

AbstractChildhood obesity increases the risk of health and cognitive disorders in adulthood. Consuming high‐fat diets (HFD) during critical neurodevelopmental periods, like childhood, impairs cognition and memory in humans and animals, affecting the function and connectivity of brain structures related to emotional memory. However, the underlying mechanisms of such phenomena need to be better understood. This study aimed to investigate the neurochemical profile of the amygdala and hippocampus, brain structures involved in emotional memory, during the acquisition of conditioned odor aversion in male rats that consumed a HFD from weaning to adulthood. The rats gained weight, experienced metabolic changes, and reduced insulin sensitivity and glucose tolerance. Rats showed enhanced odor aversion memory, contrary to the expected cognitive impairments. This memory enhancement was accompanied by increased noradrenergic and glutamatergic neurotransmission in the amygdala and hippocampus. Importantly, this upregulation was specific to stimuli exposure, as basal neurotransmitter levels remained unaltered by the HFD. Our results suggest that HFD modifies cognitive function by altering neurochemical signaling, in this case, upregulating neurotransmitter levels rendering a stronger memory trace, demonstrating that metabolic dysfunctions do not only trigger exclusively detrimental plasticity processes but also render enhanced plastic effects depending on the type of information.

Interface interactions driven antioxidant properties in olive leaf extract/cellulose nanocrystals/poly(butylene adipate-co-terephthalate) biomaterials

Functional packaging represents a new frontier for research on food packaging materials. In this context, adding antioxidant properties to packaging films is of interest. In this study, poly(butylene adipate-co-terephthalate) (PBAT) and olive leaf extract (OLE) have been melt-compounded to obtain novel biomaterials suitable for applications which would benefit from the antioxidant activity. The effect of cellulose nanocrystals (CNC) on the PBAT/OLE system was investigated, considering the interface interactions between PBAT/OLE and OLE/CNC. The biomaterials' physical and antioxidant properties were characterized. Morphological analysis corroborates the full miscibility between OLE and PBAT and that OLE favours CNC dispersion into the polymer matrix. Tensile tests show a stable plasticizer effect of OLE for a month in line with good interface PBAT/OLE interactions. Simulant food tests indicate a delay of OLE release from the 20 wt% OLE-based materials. Antioxidant activity tests prove the antioxidant effect of OLE depending on the released polyphenols, prolonged in the system at 20 wt% of OLE. Fluorescence spectroscopy demonstrates the nature of the non-covalent PBAT/OLE interphase interactions in π-π stacking bonds. The presence of CNC in the biomaterials leads to strong hydrogen bonding interactions between CNC and OLE, accelerating OLE released from the PBAT matrix.

Cyclic quenching treatment doubles the Charpy V-notch impact energy of a 2.3 GPa maraging steel

A cyclic quenching treatment (CQT) succeeded in turning a 2.3 GPa maraging steel with a Charpy impact energy of 9 J into a new grade with the same strength but a Charpy impact energy of 20 J upon 4 cyclic treatments. The improvement of mechanical properties is attributed to the refinement and increased chemical heterogeneity of the martensitic substructure, rather than the refinement of prior austenite grain (PAG), as well as the Transformation-Induced Plasticity (TRIP) effect facilitated by small austenite grains. The role of local segregation of Ni during CQT in the formation of Ni-rich austenite grains, Ni-rich martensite laths and Ni-poor martensite laths, was investigated and verified by DICTRA simulations. This study highlights the important influence of Ni partitioning behavior during CQT, providing insights into microstructural evolution and mechanical properties.

Designing the heterogeneous microstructure via a direct warm rolling process to synergistically enhance the strength-ductility in a medium Mn steel

This work introduced a facile method for fabricating heterostructures in a medium Mn steel via a direct warm rolling process. The heavy warm rolling promoted the transformation of metastable austenite (∼12.2 vol%) into hard domain α’ martensite, which formed a heterogeneous microstructure with the untransformed γ (soft domain). After 600 °C re-annealing, the hard domain α’ re-reversed to α + γ, and the heterostructure disappeared. Compared to the homogeneous structure, the heterostructure exhibited the synergistic enhancement of strength-ductility (yield strength (YS): 782 → 1113 MPa; ultimate tensile strength (UTS): 1099 → 1304 MPa; total elongation (TEL): 20.8 % → 21.7 %). Quantitative analysis showed that the heterogeneous deformation induced (HDI) strengthening (∼261 MPa) was the primary contributor to the increased ΔYS (782 → 1113 MPa) value, rather than the traditional strengthening mechanisms. Transformation induced plasticity (TRIP) and twinning induced plasticity (TWIP) effect were the main deformation mechanisms of both homogeneous/heterogeneous structures. However, compared to the homogeneous microstructure, the heterogeneous structure possessed the more pronounced TRIP and HDI hardening effects as well as L-C locks, the cooperative effect of these three factors further improved the strain hardening ability to break through the strength-ductility trade-off dilemma.

Finite Element Analysis of Plastic Deformation in Ultrasonic Vibration Superimposed Face Milling of Steel X46Cr13.

Ultrasonic vibration superimposed face milling enables the generation of predefined surface microstructures by an appropriate setting of the process parameters. The geometrical reproducibility of the surface characteristics depends strongly on the plastic material deformation. Thus, the precise prediction of the emerging surface microstructures using kinematic simulation models is limited, because they ignore the influence of material flow. Consequently, the effects of plastic as well as elastic deformation are investigated in depth by finite element analysis. Microstructured surfaces resulting from these numerical models are characterized quantitatively by areal surface parameters and compared to those from a kinematical simulation and a real machined surface. A high degree of conformity between the values of the simulated surfaces and the measured values is achieved, particularly with regard to material distribution. Deficits in predictability exist primarily due to deviations in plastic deformation. Future research can address this, either by implementing a temperature consideration or adapting specific modeling aspects like an adjusted depth of cut or experimental validated material parameters.

Plastic pollution affects ecosystem processes including community structure and functional traits in large rivers

Plastics in aquatic ecosystems rapidly undergo biofouling, giving rise to a new ecosystem on their surface, the 'plastisphere.' Few studies quantify the impact of plastics and their associated community on ecosystem traits from biodiversity and functional traits to metabolic function. It has been suspected that impacts on ecosystems may depend on its state but comparative studies of ecosystem responses are rare in the published literature. We quantified algal biomass, bacterial and algal biodiversity (16S and 18S rRNA), and metabolic traits of the community growing on the surface of different plastic polymers incubated within rivers of the Lower Mekong Basin. The rivers selected have different ecological characteristics but are similar regarding their high degree of plastic pollution. We examined the effects of plastics colonized with biofilms on ecosystem production, community dark respiration, and the epiplastic community's capability to influence nitrogen, phosphorus, organic carbon, and oxygen in water. Finally, we present conceptual models to guide our understanding of plastic pollution within freshwaters. Our findings showed limited microalgal biomass and bacterial dominance, with potential pathogens present. The location significantly influenced community composition, highlighting the role of environmental conditions in shaping community development. When assessing the effects on ecosystem productivity, our experiments showed that biofouled plastics led to a significant drop in oxygen concentration within river water, leading to hypoxic/anoxic conditions with subsequent profound impacts on system metabolism and the capability of influencing biogeochemical cycles. Scaling our findings revealed that plastic pollution may exert a more substantial and ecosystem-altering impact than initially assumed, particularly in areas with poorly managed plastic waste. These results highlighted that the plastisphere functions as a habitat for biologically active organisms which play a pivotal role in essential ecosystem processes. This warrants dedicated attention and investigation, particularly in sensitive ecosystems like the Mekong River, which supports a rich biodiversity and the livelihoods of 65 million people.

Effects of plasticity and genetic divergence in phenotypic trait expression of sulfide spring fishes

Effects of plasticity and genetic divergence in phenotypic trait expression of sulfide spring fishes

Heterogeneous Multi-Phase Grains Improving the Strength-Ductility Balance in Warm-Rolled Fe-18Mn-3Ti Steel.

The thermal properties, microstructure, and mechanical properties of Fe-18Mn-3Ti (wt%) were investigated, focusing on the effects of different heat-treatment processes. Results revealed that the 450 °C warm-rolling sample (450 WR) exhibited promising mechanical properties. Specifically, this sample displayed a yield strength of 988 MPa, an ultimate tensile strength of 1052 MPa, and total elongation of 15.49%. Consequently, a favorable strength-ductility balance was achieved. The strain-hardening ability surpassed that of the cold rolling sample (CR). Microstructure analysis indicated the simultaneous occurrence of dynamic equilibrium between grain deformation and re-crystallization because of the co-influence of thermal and strain in the warm rolling process. This desirable mechanical property was attributed to the presence of a multi-phase (α-martensite, austenite, and ε-martensite) and heterogeneous microstructure. The improvement of ultimate tensile strength was based on grain refinement, grain co-deformation, and the transformation-induced plasticity (TRIP) effect in the early stage of plastic deformation (stage Ⅰ). The improvement of ultimate elongation (TEL) was ascribed to the TRIP effect in the middle stage of plastic deformation (stage Ⅱ).

Effect of grain size and segregation on the cryogenic toughness mechanism in heat-affected zone of high manganese steel

High manganese steels have been nominated as desirable materials used for various cryogenic applications due to their excellent cryogenic toughness caused by twinning. High manganese steel welded joints were obtained through gas metal arc welding, and the microstructural differences at three subzones of heat-affected zone (HAZ) were utilized. The aim was to investigate the effect of grain size and Mn/C/Cu segregation on the cryogenic toughness mechanism of high manganese steel welded joints. The results indicate that the average impact absorbed energies at −196 °C for 1.0, 3.0, and 5.0 mm from the fusion line (denoted by FL + 1, FL + 3, and FL + 5) is 118.6 J, 102.4 J, and 117.2 J, respectively. Compared with base metal, the embrittlement occurred in HAZ. Large grains improve toughness, while small grain boundaries, segregation, and precipitation in HAZ deteriorate toughness. Larger grain size facilitates the primary twins with thinner inter-twin spacing and twin thickness, and the high density of these primary twins inhibits the activation of secondary twins. This, in turn, enhances cryogenic impact toughness. Although the stacking fault energy (SFE) throughout the welding joint lays within the range for the twinning-induced plasticity effect, the enrichment of Mn/C/Cu slightly increases the local SFE and critical resolved shear stress for twining within the segregation zone. This phenomenon makes the activation of primary twins more challenging. Furthermore, the C segregation at grain boundaries leads to the precipitation of fine Cr23C6 carbides. These carbides serve as crack initiation points during impact tests, contributing to degradation in cryogenic impact toughness.

Fabrication of high strength-ductility aluminum alloy heterogeneous plates using additive manufacturing and hot rolling process

Aluminum alloy heterogeneous plate has great potential applications in automotive, military, aerospace, and other fields due to its excellent mechanical properties and ability to resist ballistic missile penetration. In the present work, a 5356/7A48 aluminum alloy heterogeneous plate with high strength-ductility and excellent interfacial metallurgical bonding strength was prepared using wire-arc additive manufacturing and hot rolling (WAAM+HR) process. The yield strength and ultimate tensile strength were 280.2 MPa and 392.3 MPa, respectively, both of which were between 5356 and 7A48 alloys, but the elongation was excellent, up to 22%. Its excellent comprehensive mechanical properties far exceed those of Al/Al heterogeneous plates reported in previous studies. In addition, compared with traditional clad plates, its fracture displacement is improved by 48.8%, showing remarkably high interlayer bonding strength. The soft layer 5356 and the hard layer 7A48 beared the main plastic strain and normal stress respectively, resulting in back-stress strengthening at the interlayer interface, which was the fundamental reason for the synergistic effect of strength and plasticity. Furthermore, even at the maximum bending angle of 180°, the heterogeneous plate did not show any sign of fracture, thanks to the fact that the outer soft-clad layer accommodated most of the bending deformation. The heterogeneous lamella structure, high constraint of hard layer to soft layer, and high geometrically necessary dislocations (GNDs) density of interfaces effectively stimulated the back stress strengthening and dislocation hardening, so that the 5356/7A48 aluminum alloy heterogeneous plate exhibited excellent comprehensive mechanical properties. The proposed WAAM+HR process provides an approach for the preparation of multi-functional heterogeneous plates with high strength-ductility and superior bonding strength.

МОДИФИЦИРОВАНИЕ СВОЙСТВ ГИДРОТЕХНИЧЕСКИХ БЕТОНОВ ДОБАВКАМИ НА ОСНОВЕ ВЫСОКОМОЛЕКУЛЯРНЫХ СОЕДИНЕНИЙ

Ensuring high water resistance, frost resistance and corrosion resistance of hydraulic structures is achieved by creating concrete with a dense structure that can absorb aggressive influences. This is possible by modifying the structure of concrete with polymer additives of new generation. The introduction of polymer additives has a plasticizing effect and contributes to the preservation of technological properties of the concrete mixture, modifies the pore structure of concrete and influences the formation of cement stone strength. The paper presents the results of research on the effect of polymer additive based on polyvinylpyrrolidone on the basic properties of Portland cement binder. It was found that the compressive strength at the age of 2 days increases by 7% at the content of polymer additive in the amount of 0.8%. Also, in-troduction of polymer additive increases the compressive strength at the age of 28 days at its content of 0.6 and 0.8% by 22 and 27%, respectively. The effect of polymer modifier on the formation of the initial structure, manifested in the increase in the time of the beginning and accel-eration of the end of setting has been established. The kinetics of heat release of cement dough in the presence of polymeric modifier in the amount of 0.6 % has been studied. The data on the phase composition of cement stone in the presence of polymer modifier are given. It is established by means of electron microscopic analysis that the introduction of polymeric admixture promotes modification of cement stone microstructure with formation of more dense homogeneous structure. The given research results are taken into account in the development of concrete compositions with a set of specified properties required for the construction of hydraulic structures.

Cooperative roles of twinning, transformation and strain partitioning on the excellent cryogenic strength-toughness synergy of dual-heterogeneous metastable high entropy alloys

In a metastable Fe50Mn30Co10Cr10 high entropy alloy (HEA), a dual-heterogeneous structure, encompassing both grain size and dislocation heterogeneity, has been constructed to obtain excellent cryogenic mechanical performance by varying the annealing temperature (630 and 740 °C) following severe deformation. The HS-630 sample, consisting of recovered coarse-grains (CG), recrystallized fine-grains (FGs) and un-recrystallized ultrafine-grains (UFGs), possesses higher yield strength (YS) of ∼965 MPa, ultimate tensile strength (UTS) of ∼1680 MPa and uniform elongation (UEL) of ∼45 % when compared to the fully-recrystallized HS-740 sample at liquid nitrogen temperature (LNT). The difference in YS is primarily caused by the grain boundary and dislocation strengthening of UFGs, whereas the higher ductility of the HS-630 sample is associated with the hierarchical activation of transformation- and twinning-induced plasticity (TRIP and TWIP) effects, and compatible strain partitioning between heterogeneous domains. The dual-heterogeneity results in different critical stresses of ε-phase nucleation in heterogeneous domains, and promotes sustainable TRIP effect in CGs and the emergence of TWIP effect in UFGs with strain progressing. Moreover, the strain of the ductile transformed ε-phase is mainly accommodated by non-basal slip, which contributes to the strain hardening in the later deformation stage. Furthermore, the higher cryogenic impact toughness of the HS-630 sample can be attributed to the synergistic effects of the fracture mode, the transformation characteristics, and the heterogeneous strain partitioning.

Neuromodulatory Responses Elicited by Intermittent versus Continuous Transcranial Focused Ultrasound Stimulation of the Motor Cortex in Rats.

Transcranial focused ultrasound stimulation (tFUS) has emerged as a promising neuromodulation technique that delivers acoustic energy with high spatial resolution for inducing long-term potentiation (LTP)- or depression (LTD)-like plasticity. The variability in the primary effects of tFUS-induced plasticity could be due to different stimulation patterns, such as intermittent versus continuous, and is an aspect that requires further detailed exploration. In this study, we developed a platform to evaluate the neuromodulatory effects of intermittent and continuous tFUS on motor cortical plasticity before and after tFUS application. Three groups of rats were exposed to either intermittent, continuous, or sham tFUS. We analyzed the neuromodulatory effects on motor cortical excitability by examining changes in motor-evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS). We also investigated the effects of different stimulation patterns on excitatory and inhibitory neural biomarkers, examining c-Fos and glutamic acid decarboxylase (GAD-65) expression using immunohistochemistry staining. Additionally, we evaluated the safety of tFUS by analyzing glial fibrillary acidic protein (GFAP) expression. The current results indicated that intermittent tFUS produced a facilitation effect on motor excitability, while continuous tFUS significantly inhibited motor excitability. Furthermore, neither tFUS approach caused injury to the stimulation sites in rats. Immunohistochemistry staining revealed increased c-Fos and decreased GAD-65 expression following intermittent tFUS. Conversely, continuous tFUS downregulated c-Fos and upregulated GAD-65 expression. In conclusion, our findings demonstrate that both intermittent and continuous tFUS effectively modulate cortical excitability. The neuromodulatory effects may result from the activation or deactivation of cortical neurons following tFUS intervention. These effects are considered safe and well-tolerated, highlighting the potential for using different patterns of tFUS in future clinical neuromodulatory applications.

Development of a Biodegradable Cassava Starch Biofilm based on a Combination of Plasticizers with Bio‐SiO2 Extracted from Sugarcane Leaves

AbstractThis study prepares biodegradable biofilms for packaging applications from biomass to help reduce plastic waste while also adding value to biomass. Furthermore, the effects of plasticization with 30 wt% plasticizer (relative to the mass of cassava starch) by glycerol (G), sorbitol (S), and a mixture of glycerol and sorbitol (GS) plasticizers are investigated, and the effects of bio‐SiO2 particles extracted from sugarcane leave via the sol–gel method are evaluated in terms of the mechanical and biodegradability properties of the cassava starch‐based biofilms. Biofilms used for packing applications must be insoluble and exhibit good elongation properties. In this context, the results indicate that the GS mixture produces a biofilm that exhibits these desirable properties. Thus, cassava starch‐based biofilms are prepared using GS and varying concentrations of the bio‐SiO2 particles (i.e., 0, 0.5, 1, and 1.5 wt%). The films containing bio‐SiO2 exhibit significantly lower water solubilities and moisture contents than the corresponding bio‐SiO2‐free films. Additionally, the inclusion of bio‐SiO2 particles increases the water resistance properties of the biofilms. Overall, the results suggest that cassava starch films prepared using a mixture of plasticizers and reinforced with bio‐SiO2 particles can be considered a safe material for application in biodegradable food packaging.

Practical Technology of Toughening Epoxy Resin (II): Modification Effects of Special Engineering Plastics on Epoxy Resin

The effects of Special engineering plastics (SEP) such as polyether ether ketone (PEEK), polyimide (PI), thermoplastic polyimide (TPI), polyphenylene sulfide (PPS), polysulfone (PSF), liquid crystal polymer (LCP), polyaromatic (PAR) on the mechanical, thermal and electrical properties of epoxy resins were studied in this paper. The engineering plastics with rigid and active elements produce differential phase in the epoxy curing process, which can absorb energy under stress, prevent micro-crack diffusion, and improve the mechanical properties of epoxy resin, including tensile, compression and impact strength. SEP with better heat resistance than epoxy resins are beneficial for improving the heat resistance of epoxy resins. During the epoxy curing process, strong intermolecular forces are generated between SEP and epoxy resin, which further enhances the heat resistance of modified epoxy resins. Better insulation of epoxy resin are achieved by adding engineering plastics with fine insulation equipment. PSF with poor dispersion aggregates to form a weak interface layer, which first fails under stress, and its main mechanical properties slightly decrease. The dispersion of pulp like LCP in epoxy resin is poor, and there is no significant improvement in the mechanical properties of epoxy resin. PAR are difficult to form a homogeneous phase in epoxy resin and cannot be used for epoxy resin modification research.

Effect of reaction conditions on pyrolysis performance of waste plastics loaded with Ni/ZSM-5 catalyst

Ni/ZSM-5 catalysts were prepared by uniformly loading the active metal Ni to ZSM-5 zeolite using excessive wet impregnation method, and the characterization tests of XRD, SEM, H2-TPR, and NH3-TPD were carried out. For the prepared Ni/ZSM-5 catalyst, the pyrolysis–catalytic reforming of waste plastics for gas production performance was explored under different reaction temperatures, steam-carbon (S/C) ratio, catalyst addition amount, and plastic type. The results showed that the gas production volume and gas quality of pure pyrolysis of HDPE and catalytic pyrolysis of Ni/ZSM-5 were improved with the increase of temperature. Given the thermal economy, the optimal pyrolysis temperature was 700 °C, the catalytic gas production was 900 mL, and the hydrogen concentration was 64.4 %. S/C ratio of 1.5 and plastic: catalyst of 1 was the best reaction condition, under which the gas production was 1020 mL and the hydrogen concentration was 65.1 %, respectively. In addition, an appropriate increase in the amount of steam and the addition of catalysts would greatly optimize the final gas production performance. However, excess steam and catalysts was unfavorable to the gas production of plastic pyrolysis, resulting in a waste of resources. Finally, as for the gas production of four plastics, LDPE had the best pyrolysis gasification effect with gas yield of 1040 mL and hydrogen concentration of 65.7 %. The order of catalytic pyrolysis effect of different plastics was LDPE > HDPE > PP > PS.

A Multiphysics Thermoelastoviscoplastic Damage Internal State Variable Constitutive Model including Magnetism.

We present a macroscale constitutive model that couples magnetism with thermal, elastic, plastic, and damage effects in an Internal State Variable (ISV) theory. Previous constitutive models did not include an interdependence between the internal magnetic (magnetostriction and magnetic flux) and mechanical fields. Although constitutive models explaining the mechanisms behind mechanical deformations caused by magnetization changes have been presented in the literature, they mainly focus on nanoscale structure-property relations. A fully coupled multiphysics macroscale ISV model presented herein admits lower length scale information from the nanoscale and microscale descriptions of the multiphysics behavior, thus capturing the effects of magnetic field forces with isotropic and anisotropic magnetization terms and moments under thermomechanical deformations. For the first time, this ISV modeling framework internally coheres to the kinematic, thermodynamic, and kinetic relationships of deformation using the evolving ISV histories. For the kinematics, a multiplicative decomposition of deformation gradient is employed including a magnetization term; hence, the Jacobian represents the conservation of mass and conservation of momentum including magnetism. The first and second laws of thermodynamics are used to constrain the appropriate constitutive relations through the Clausius-Duhem inequality. The kinetic framework employs a stress-strain relationship with a flow rule that couples the thermal, mechanical, and magnetic terms. Experimental data from the literature for three different materials (iron, nickel, and cobalt) are used to compare with the model's results showing good correlations.

Colyophilized Sugar-Polymer Dispersions for Enhanced Processing and Storage Stability.

Sucrose and trehalose pharmaceutical excipients are employed to stabilize protein therapeutics in a dried state. The mechanism of therapeutic protein stabilization is dependent on the sugars being present in an amorphous solid-state. Colyophilization of sugars with high glass transition polymers, polyvinylpyrrolidone (PVP), and poly(vinylpyrrolidone vinyl acetate) (PVPVA), enhances amorphous sugar stability. This study investigates the stability of colyophilized sugar-polymer systems in the frozen solution state, dried state postlyophilization, and upon exposure to elevated humidity. Binary systems of sucrose or trehalose with PVP or PVPVA were lyophilized with sugar/polymer ratios ranging from 2:8 to 8:2. Frozen sugar-PVPVA solutions exhibited a higher glass transition temperature of the maximally freeze-concentrated amorphous phase (Tg') compared to sugar-PVP solutions, despite the glass transition temperature (Tg) of PVPVA being lower than PVP. Tg values of all colyophilized systems were in a similar temperature range irrespective of polymer type. Greater hydrogen bonding between sugars and PVP and the lower hygroscopicity of PVPVA influenced polymer antiplasticization effects and the plasticization effects of residual water. Plasticization due to water sorption was investigated in a dynamic vapor sorption humidity ramping experiment. Lyophilized sucrose systems exhibited increased amorphous stability compared to trehalose upon exposure to the humidity. Recrystallization of trehalose was observed and stabilized by polymer addition. Lower concentrations of PVP inhibited trehalose recrystallization compared to PVPVA. These stabilizing effects were attributed to the increased hydrogen bonding between trehalose and PVP compared to trehalose and PVPVA. Overall, the study demonstrated how differences in polymer hygroscopicity and hydrogen bonding with sugars influence the stability of colyophilized amorphous dispersions. These insights into excipient solid-state stability are relevant to the development of stabilized biopharmaceutical solid-state formulations.

Plastic and Micro/Nanoplastic Pollution in Sub-Saharan Africa: Challenges, Impacts, and Solutions

Sub-Saharan Africa faces increasing levels of plastic production and importation, unregulated usage, and inadequate waste management systems. This region’s harsh conditions often lead to plastic breaking down into microplastics and nanoplastics. This review explores the abundance of micro/nanoplastics across different environmental mediums, such as surface waters, sediments, and aquatic organisms, in sub-Saharan African countries. It also highlights knowledge gaps concerning the region’s abundance of micro/nanoplastics. The effects of plastics and micro/nanoplastics on food production, water quality, health, and the environment are discussed. Strategies to address the challenges of plastic pollution are proposed. Finally, the review concludes with future perspectives for addressing the ongoing challenges of plastic waste management in sub-Saharan Africa. The materials for this study were sourced from published articles on Scopus, Google Scholar, ResearchGate, and additional platforms, including reports and various press releases, using keywords such as plastic waste, micro/nano-plastic, sub-Saharan Africa, toxicity, and circular economy. Articles were initially screened by reviewing abstracts, followed by a thorough reading of full papers to identify relevant studies. Key information was extracted from these selected articles and incorporated into this review.

Clinical Results of Asymmetric Blepharoplasty Plastic Repair.

To investigate plastic surgery repair's effects and adverse reactions in the clinical therapy of asymmetric double eyelids. All 126 sufferers who came to the hospital for asymmetric double eyelid plastic repair from January 2022 to October 2022 were selected as the research objects, and they were divided into a control group and an observation group using the random number method, with 63 cases in each group, in which sufferers in the control group underwent full incision blepharoplasty and sufferers in the observation group underwent small incision liposuction with submerged sutures. The general data, treatment results, treatment satisfaction, related surgical indicators, and frequency of adverse reactions of the 2 groups of sufferers with asymmetric double eyelid plastic repair were compared. It had no statistically obvious distinction between the control group and the observation group of sufferers in terms of general data such as sex, age, weight, and height ( P> 0.05); the total therapy efficiency of the sufferers in the observation group (95.24%) was greater than the control group (74.60%), with P value <0.05; the total treatment satisfaction of the patients in the observation group (96.83%) was significantly higher than that in the control group (76.19%), with P value <0.05; compared with the control group, patients in the observation group had shorter operative time and healing time and less intraoperative bleeding, with P value < 0.05; the total frequency of adverse reactions of sufferers in the observation group (4.76%) was less than the control group (17.46%), with P value < 0.05. Small incision liposuction with submerged sutures for plastic repair has significant efficacy, relatively high patient satisfaction, and low incidence of adverse reactions, in line with patient esthetic review, which has a broad clinical application prospect.