Stability Effects Research Articles

Leguminous green mulching alters the microbial community structure and increases microbial diversity by improving nitrogen availability in subtropical orchard systems in China

Microorganisms, the major decomposers of plant residues, are crucial for soil nutrient cycling. Living grass mulching effectively alters microbial community structure and promotes nutrient cycling. However, its consistency with mulching ages and growth periods remains unclear. Therefore, this study aims to clarify the dynamic characteristics of microbial communities and enzyme activities across different mulching ages. In this study, high-throughput sequencing technology was used to investigate bacterial and fungal community evolution in three mulching treatments with Vicia villosa for 8 years (VV_8), 4 years (VV_4), and clean tillage in a citrus orchard. This study covered three growth periods (citrus–grass: spring sprouting to budding period [SSBP], fruit swelling to withering period [FSWP], and fruit maturity to seeding period [FMSP]). The results showed that VV_4 and VV_8 treatments increased bacterial and fungal alpha diversity as well as the activities of nitrogen (N), carbon (C), and phosphorus cycling enzymes. C-cycling enzyme activity was the primary key factor driving changes in microbial diversity across growth periods. Under leguminous green mulching, bacteria alpha diversity increased the most during FSWP, while fungi increased the most during FMSP. Additionally, the relative abundance of Ascomycota and Basidiomycota significantly increased during the FSWP and FMSP, reaching 63.65–73.80 % and 79.73–84.51 %, respectively. With increasing mulching ages, the structural stability and synergistic effects of microorganisms were correspondingly enhanced. Furthermore, available nutrients determined microbial community evolution, with N availability being a key factor influencing microbial diversity, especially fungal diversity. In conclusion, as mulching ages increase, improved nutrient availability gradually enhances microbial diversity, synergistic interactions, and nutrient cycling functions, with copiotrophic taxa occupying a key position in the microbial network. FSWP is a critical turning point for enhancing microbial activity and C-cycling function. This study offers theoretical support for developing microbial regulation strategies to improve soil quality in orchard management practices.

The Pharmacokinetic Interaction of Tirabrutinib with Voriconazole, Itraconazole, and Fluconazole in SD Rats by UPLC-MS/MS.

Tirabrutinib is an orally effective, approved, and highly selective second-generation Bruton's tyrosine kinase (BTK) inhibitor for the treatment of recurrent or refractory primary central nervous system lymphoma (PCNSL). This study aimed to develop an ultra-high performance liquid chromatography- tandem mass spectrometry (UPLC-MS/MS) method for the determination of tirabrutinib concentration in rat plasma, where zanubrutinib was used as an internal standard (IS). This method was also applied to study whether tirabrutinib would interact with voriconazole, itraconazole, and fluconazole in rats, providing a reference value for clinical medication guidance. In the current study, the organic solvent protein precipitation method was used to treat plasma samples, which is simple and reproducible. Tirabrutinib (m/z 455.32 → 320.21) and zanubrutinib (m/z 472.13 → 455.04) were separated on a Waters Acquity BEH C18 column (2.1 × 50 mm, 1.7 μm) and detected by multiple reaction monitoring (MRM) in positive ionization mode. The method showed good linearity in the range of 5-3000 ng/mL for tirabrutinib with the lower limit of quantification (LLOQ) of 5 ng/mL. The recovery and matrix effects were 85.7-91.0% and 102.0-113.3%, respectively. The accuracy, precision, stability, and carry-over effect were also acceptable. The method could also be used for determining the pharmacokinetic interaction of tirabrutinib in rats. The results showed AUC0→∞ of tirabrutinib to be increased by 139.3% and 83.9% in the presence of voriconazole and fluconazole, respectively, while itraconazole had little effect. It is necessary to monitor the concentration of tirabrutinib in patients when it is combined with voriconazole and fluconazole to achieve a better therapeutic effect and reduce the risk of adverse reaction. Further research should be conducted in the future.

Novel functional carriers based on Spirulina protein for the delivery of curcumin with improved stability and antioxidant efficiency

The potential of sustainably sourced Spirulina protein (SP), and SP nanoparticles (SPNP) obtained by heating gelation and ultrasound treatment as functional carriers for curcumin (Cur) was studied. The antioxidant activity, encapsulation performance, stability and digestive properties of the delivery system were analyzed. Compared with SP, SPNP exhibited higher hydrophobicity, and its antioxidant capacity was enhanced due to increased exposure of chromophores. The encapsulation performance of Cur-loaded complexes was influenced by the protein-Cur mass ratio, and the encapsulation efficiency of SPNP was significantly higher than that of SP (p < 0.05). Because of the better binding affinity, SPNP-Cur complexes showed improved thermal stability and UV protection effect. SP and SPNP all exhibited antioxidant synergism with Cur, and the antioxidant efficiency was closely related to pH, dissociating solvents, UV irradiation and digestion. The bioaccessibility of Cur was also greatly improved. It suggests that Spirulina protein may be an ideal carrier for delivering nutraceutical compounds.

Insights into the thermal stabilization mechanism of zeolitic imidazolate framework-8 for poly(vinyl chloride)

The thermal stability of zeolitic imidazolate framework-8 (ZIF-8) for poly(vinyl chloride) (PVC) has received attention, but its thermal stabilization mechanism needs further clarification. Herein, the stearic acid-modified ZIF-8 with high specific surface area and large pore volume was effectively synthesized by using zinc stearate as the zinc source for the first time. Modification of stearic acid results in larger adsorption capacity of ZIF-8 for HCl and better thermal stability effect for PVC, especially long-term thermal stability. Moreover, the thermal stability mechanism of ZIF-8 for PVC was demonstrated by experiments and theoretical calculations. In addition to absorbing HCl to eliminate autocatalytic degradation of PVC, ZIF-8 disintegrates and may form 2-methylimidazole-Zn-Cl salt complex instead of free ZnCl2, avoiding the negative zinc burning effect. Furthermore, the Diels-Alder reaction between imidazole ring and degraded PVC prevents the extension of the conjugated double bonds of PVC and delays the deepening of the color of PVC.

Effect of salt ions (Na+, Ca2+ and Mg2+) and EOR anionic and nonionic surfactants on the dispersion stability of cellulose nanocrystals

The application of cellulose nanocrystals (CNCs) in enhanced oil recovery (EOR) is a developing hotspot. To improve the stability of CNCs in salt environments, the effects of sodium dodecylbenzene sulfonate (SDBS) and polyoxyethylene sorbitan monooleate (Tween 80) on the stability of CNCs in the presence of sodium (Na+), calcium (Ca2+) and magnesium (Mg2+) were investigated. The range of salt ions and the stability mechanism for improving the CNCs stability in the presence of SDBS and Tween 80 were pointed out. SDBS improved the stability of CNCs in the presence of 30–100 mM Na+, 1–2 mM Ca2+ and 2 mM Mg2+, respectively. Tween 80 improved the stability of CNCs in the presence of Na+ ≤ 300 mM, Ca2+ ≤ 10 mM and Mg2+ ≤ 10 mM, respectively. The mechanism was explained by the bridging effect of salt ions, electrostatic effect and spatial stability effect. The combined systems of surfactants (SDBS and Tween 80) with CNCs exhibited strong emulsifying properties, low interfacial tension (0.023 mN/m and 1.85 mN/m), and the ability to alter the wettability of oil wet rocks. This made the combined systems have better oil displacement performance.

Macroeconomic stability and economic growth: Evidence from Bangladesh

This paper investigates the link and causal relationship between macroeconomic stability and economic growth in Bangladesh for the period 1971 through 2023. Cointegration, vector error correction technique, and the Granger causality test are applied for this purpose. The paper finds sufficient evidence that macroeconomic stability and economic growth are positively related with each other in the long run. Like the long-run relationship, government consumption and investment proxy are significant in the short-run among all the factors of stability while only government consumption and inflation show some causal relationship with growth. Thus, the results are suggestive of the fact that it is better to comment about factors of stability separately rather than macroeconomic stability as a whole. The results also emphasize evaluation of both the long-run and the short-run effects of macroeconomic stability separately for effective policymaking.

Recycling steel slag as aggregate in developing an ultra-thin friction course with high comprehensive road performance

The demand for skid-resistant and wear-resistant alternative aggregates in the preparation of ultra-thin friction course (UTFC) asphalt mixtures is a key direction for achieving high durability and low-carbon development in pavement maintenance. As a typical industrial waste, steel slag with high alkalinity and strong adhesion can facilitate the mechanical property of asphalt mixtures. However, few researches focused on the impact of steel slag on the comprehensive road performance of UTFC mixtures. Hence, the issue merits systematic exploration. In this study, the chemical components, microstructure and morphological characteristics of three steel slags (GXSS, HBSS and IMSS) obtained from different sources were surveyed. Then the stone matrix asphalt (SMA)-5 and open-grade friction courses (OGFC)-5 mixtures with different steel slags were fabricated. And their comprehensive road performances were quantitatively explored via the improved radar chart. The results indicate that steel slag with approximately 40 % Ca content, about 20 % Fe content, irregular shapes and tiny pores endows its wear resistance and strong adhesion. IMSS demonstrates the largest average angularity and form 2D values of 3850 and 7.28, respectively, representing its significant crowding function and interlocking structure. Incorporating steel slag remarkably reinforces the rutting resistance, skid resistance and anti-interlayer shear performance of UTFC. While the effect of water stability and crack resistance of UTFC depend on the category of steel slag. All three steel slags manifest the improvement function on the comprehensive assessment indexes (CAI) of OGFC-UTFC. IMSS-OGFC reveals the optimal comprehensive road performance, achieving the highest CAI of 0.9909. It is inferred that steel slag is more suitable for OGFC-UTFC than SMA-UTFC due to its relatively high CAI and consistent performance regardless of the steel slag type.

Hyaluronic acid-decorated lipid nanocarriers as novel vehicles for curcumin: Improved stability, cellular absorption, and anti-inflammatory effects

This study aimed to investigate how hyaluronic acid interfacial decoration affects the stability, cellular absorption, and anti-inflammatory effects of curcumin-loaded nanostructured lipid carriers. Nanocarriers were synthesized with an ovalbumin single layer and ovalbumin/hyaluronic acid double, mixed, or conjugated layers. All nanocarriers were spherical (200–300 nm diameter), and their encapsulation efficiency exceeded 95 %. Among the layers, the conjugated one exhibited the highest elastic surface dilatational modulus of approximately 40 mN/m, and the longest curcumin half-life of 186.07 days at 4 °C. Spearman's correlation analysis showed a negative correlation (r = −0.6698) between the recrystallization index and curcumin stability. The layer's mechanical strength improved curcumin stability by preventing crystal transition. Hyaluronic acid decoration enhanced the curcumin uptake of Caco-2 cells by 1.96–2.48 folds. Among the layers, the conjugate one was the most effective because of its strong binding constant with the receptor. Hyaluronic acid decoration improved the anti-inflammatory effects of curcumin.

Quality by Design (QbD) Approach to Develop Colon-Specific Ketoprofen Hot-Melt Extruded Pellets: Impact of Eudragit® S 100 Coating on the In Vitro Drug Release.

A pelletizer paired with hot-melt extrusion technology (HME) was used to develop colon-targeted pellets for ketoprofen (KTP). Thermal stability and side effects in the upper gastrointestinal tract made ketoprofen more suitable for this work. The pellets were prepared using the enzyme-triggered polymer Pectin LM in the presence of HPMC HME 4M, followed by pH-dependent Eudragit® S 100 coating to accommodate the maximum drug release in the colon by minimizing drug release in the upper gastrointestinal tract (GIT). Box-Behnken Design (BBD) was used for response surface optimization of the proportion of different independent variables like Pectin LM (A), HPMC HME 4M (B), and Eudragit® S 100 (C) required to lower the early drug release in upper GIT and to extend the drug release in the colon. Solid-state characterization studies revealed that ketoprofen was present in a solid solution state in the hot-melt extruded polymer matrix. The desired responses of the prepared optimized KTP pellets obtained by considering the designed space showed 1.20% drug release in 2 h, 3.73% in the first 5 h of the lag period with the help of Eudragit® S 100 coating, and 93.96% in extended release up to 24 h in the colonic region. Hence, developing Eudragit-coated hot-melt extruded pellets could be a significant method for achieving the colon-specific release of ketoprofen.

Does the size of the housing rental market stabilize regional economic fluctuations? Evidence from China's large- and medium-sized cities

The influence of the housing rental market on economic operations is a significant concern. Particularly in China, the rental market has been undergoing a transition from being disregarded to being valued. Based on an analytical framework referencing the three-sector theory of metropolitan economic growth, this study explores the impact of rental market size on regional economic fluctuations and its influence channels using a panel of 69 large and medium-sized cities from 2010 to 2019. The results indicate that increased rental market size is significantly correlated with decreased regional economic fluctuations through housing sales and labor market channels. Specifically, house price depression, house investment stability, labor allocation, and employment stability effects are crucial channels through which the size of the rental market influences regional economic fluctuations. In addition, the marginal effect of rental market size on regional economic fluctuations is smaller in cities with higher economic development. The conclusions imply that policymakers should not focus on how to unilaterally expand the housing rental market, but should strategically compensate for the defects of regional housing rental–related institutional systems.

The Role of Political Leadership Achieving Economic Growth and Project Success Through the Mediating Role of Political Stability: Investigation from Mega Project

This paper aims to understand the interdependency of political leadership, political stability, economic growth, and project success by applying the concept from the intuitional theory and Resource Based View - (RBV). This study addresses the relationship between political leadership in determining economic growth and the success of projects, arguing that leadership leads to stability of the political system that enhances economic growth and development and a conducive environment for construction projects. It also explores the mediating effect of political stability by proposing that the impact of political leadership on growth and project success is more strongly positive if the political system is stable. The data were collected from 240 professional’s team member working in a mega project in Pakistan. The research employed partial least squares structural equation modelling to confirm the direct and mediated effects. The findings demonstrated that PL exerts a favorable and substantial influence on economic growth and project success. Moreover, the results further validated that political stability mediates the relationship between political leadership, economic growth and project success. Thus, this paper extends the current literature review by offering empirical findings on the importance of political stability in mediating between political leadership, economic development, and project success. The current study also supports development of an integrated model that integrates political, economic and management strategies in politically unstable context to enhance the sustainable marketing system towards sustainable development goals. This paper has developed the theoretical framework and hypotheses that point out the importance of policymakers, project managers, and researchers adopting and implementing a comprehensive framework of integrated political, economic, and management to solve challenges of sustainable development and project performance. The proposed findings of this study are most beneficial to those countries with unstable political systems, highlighting that investment in political stability results in substantial economic and project-related returns.

Theoretical and experimental study of active vibration control of rotating composite laminated beams using Fx-NLMS algorithm

In the study, an adaptive active vibration control model of rotating composite laminated beam is presented by using the filtered-x normalized least mean square (Fx-NLMS) algorithm, and the experimental study is carried out based on the closed-loop control system. The macro fible composite (MFC) patches is employed to contruct the closed-loop control system of rotating composite laminated beam. By considering peizoelectric coupling effect and the influence of rotating angular velocity, the novel analysis model of vibration transfer function of rotating composite laminated beam with MFC patches is established. The calculation accurancy of the theoretical analysis model is validated by the experimental results. The experimental and simulation studies demonstrate that the low-frequnecy vibration of rotating composite beam is effectively controlled by using the lightweight system. The excellent stability and convergence effect of the closed-loop control system are obtained in the experimental testings. Moreover, the filter orders and learning factor on the active vibration control effect of the rotating composite beam are also stuided and discussed. This work provides a novel appoach for the low-frequency vibration control of the rotating cantilever beams by employing lightweight system.

Effects of fluorine atom numbers on electrochromic properties of the benzothiadiazole-based D-A polymers

In this work, two fluorinated D-π-A-π-D type monomers, F-EDOT and FF-EDOT, were facilely synthesized by donor-acceptor-donor method via Stille coupling reaction, with monofluorinated benzothiadiazole and difluorinated benzothiadiazole as the acceptor units and 3,4-ethylenedioxythiophene (EDOT) as the donor units. The electrochemical polymerization behavior of the fluorinated monomers, electrochemical and electrochromic properties of the corresponding fluorinated D-A polymers were compared to study the effects of different fluorine atom numbers on the optoelectronic properties of the monomers and their resultant D-A polymers. The results show that the introduction of more F atoms into the conjugated backbone increases the oxidation potential of monomers, both of them have low initial oxidation potential (0.65 V/0.70 V). As in the case of monomers, the substitution of more F atoms also leads to the decreased HOMO energy level of the polymers, thus leading to the increased band gap energy of P(FF-EDOT) (1.39 eV). This result can be attributed to the deviation of planarity and the reduced effective conjugate length. As prepared fluorinated D-A polymers also have good adhesion on the electrode surface, favorable redox activity, and outstanding redox stability (the redox activity of P(F-EDOT) remains 99 % after 1000 cycles). At the same time, the fluorinated D-A polymers also show distinguish electrochromic properties under various external potentials; both the optical contrast and coloration efficiency decreased with the increase of F atom numbers, and the corresponding response time increased. As a result, both the fluorinated D-A polymers show light green in the neutral state, P(F-EDOT) shows more obvious electrochromic performance in the near infrared region (optical contrast: 35.02 %, coloration efficiency: 159.94 cm2 C−1, and quick response time: 0.2 s), accompanied with excellent discoloration stability and optical memory effect. The study of novel fluorinated-based electrochromic materials further expands the selection of acceptor units and the application prospect of electrochromic materials.

Polyelectrolyte Complex Coated Cotton Fabrics with Hydrophobicity, Antibacterial Activity, and Flame Retardancy

AbstractCotton fabrics with the main constituent of cellulose, which is hydrophilic, bacterial infected, and flammable, are in urgent need of functionalization as a kind of widely applied material. To address these issues, in this work, modified polyelectrolyte complex (MPEC) coatings with polyethylenimine (PEI), polyphosphate (APP), and perfluorodecyltrichlorosilane modified PEI (PFTS‐PEI) are prepared to construct multi‐functionally gradient MPEC coatings on cotton fabrics. Stability and synergistic effects on hydrophobicity, antibacterial activity, and flame retardancy in this system have been studied. Notably, PFTS‐PEI with fluorine and silicone elements are confirmed to provide hydrophobicity and durability for MPEC coatings, which not only has no negative effect on other functions but also makes some improvement in antibacterial activity. This MPEC‐treated cotton fabric finally has an antibacterial rate against S. aureus and E. coli of 99.9% and 96.9%, limiting oxygen index of 28.5% and water contact angle of 118°, which can be almost maintained after 20 times washing. The modified PEC will provide an efficient strategy to achieve durable multi‐functions on cellulose‐based fabrics.

Functionalized Amyloid‐Like Protein Nanofilm‐Mediated Synergistic Disulfidptosis and Photodynamic Therapy for Preventing Postoperative Recurrence of Colorectal Cancer

Colorectal cancer (CRC) has a postoperative recurrence rate of up to 50%. Local treatment at the surgical site offers a new strategy to prevent recurrence, minimizing systemic side effects. However, these treatments often face issues like poor stability, insufficient targeting, and significant local side effects. Research shows glucose starvation can induce disulfidptosis, a novel cell death pathway, in CRC cells, suitable for precise intervention in residual tumor cells postsurgery. This study develops a biocompatible 2D therapeutic platform using amyloid‐like protein nanofilm technology for precise local synergistic intervention in disulfidptosis and photodynamic therapy (PDT) after CRC surgery. The nanofilm boasts excellent drug‐loading capacity, enzyme activity retention, ultrathin dimensions, wet adhesion, and biocompatibility. A model simulating incomplete tumor resection post‐CRC surgery shows that the GCI@nanofilm effectively inhibits recurrence through an enzyme‐catalyzed cascade reaction inducing disulfidptosis and synergizing with PDT. In summary, GCI@nanofilm overcomes multiple challenges in local postsurgical intervention, providing a foundation for precise and efficient treatment of residual tumors.

The Y44 residue point mutation in CXCL14 reveals the significance of CXCL14 protein stability in anti-tumor activity

Abstract Objectives CXCL14, a member of the CXC chemokine family, plays a significant role in tumor development, progression, and metastasis, making it a potential target for cancer diagnosis and treatment. This study aims to investigate the impact of a point mutation in the (41VSRYR45) motif of CXCL14 on its anti-tumor activity. Methods Phylogenetic analysis, tertiary structure prediction, homology modeling, and cell culture experiments were employed to assess the effects of CXCL14 mutations on protein stability and anti-tumor activity. Phylogenetic analysis identified conserved regions critical for function, while computational tools predicted structural changes due to mutations. Homology modeling provided structural insights, and cell culture experiments involved transfecting HeLa cells with wild-type or mutant CXCL14 plasmids, assessing stability and anti-tumor effects. Additionally, in vivo, xenograft experiments using nude mice were conducted to evaluate the anti-tumor efficacy of CXCL14 variants. Results The conserved Y44 site within the (41VSRYR45) motif was identified as a key ubiquitination site. Mutations Y44V and Y44F enhanced CXCL14 stability, reducing HeLa cell proliferation and migration while increasing apoptosis. In vivo, tumor xenograft experiments confirmed the stronger inhibitory effect of these CXCL14 variants on tumor growth compared to the wild-type protein. Conclusion The Y44 site in CXCL14 is crucial for its stability and anti-tumor activity. Mutations Y44V and Y44F enhance CXCL14 stability and anti-tumor effects, suggesting that targeting this site could be a promising therapeutic strategy for cervical cancer.

High stability and strong hydrophobic hindrance effect of core–shell NaX/polyacrylate composite for CO2 capture

It is well known that zeolite NaX excels at capturing CO2 in dry flue gas, but maintaining its excellent CO2 adsorption capacity in the presence of water remains a huge challenge. In order to significantly reduce the water adsorption of NaX while ensuring its high CO2 adsorption performance, a millimeter-sized spherical NaX/polyacrylate composite with a core–shell structure has been successfully developed through the structural modulation strategy. Here, NaX was uniformly crystallized inside the hydrophobic polyacrylate, and the crystal structure was in situ modulated using functionalized tetraethylenepentamine, so that the unique coupling of the two structures and functions achieves strong hydrophobic hindering performance. Compared with the pristine NaX, NaX/polyacrylate shows a 64.77 % reduction in water adsorption (25 °C, 11 % RH) of 5.20 mmol·g−1. The modulated nanocrystals expose more accessible adsorption active sites, so that the CO2 working capacity of the composite increases to 1.3 times that of NaX. To the best of our knowledge, this is the best case of a material that can retain excellent adsorption performance even after hydrophobic modification. More importantly, the CO2 capacity hardly declined in 100 adsorption–desorption cycles. This work provides a generalized solution to enhance the surface hydrophobicity of zeolite-like materials while maintaining their high CO2 adsorption capacity in practical applications.

Synthesis and performance study of amphoteric polymer suspension stabilizer for cementing slurry at ultra-high temperature

As the number of ultra-deep wells increases, maintaining the suspension stability of cement slurry at ultra-high temperatures becomes increasingly challenging; the development of a suspension stabilizer suitable for ultra-high temperature environments is imperative. Therefore, this study synthesized a temperature-resistant polymer suspension stabilizer (LHAP) using 2-acrylamide-2-methylpropanesulfonic acid (AMPS), N, N-dimethyl acrylamide (DMAA), 4-acryloylmorpholine (ACMO), and quaternary ammonium cationic hydrophobic long-chain monomer hexadecyl dimethylallyl ammonium chloride (DMAAC-16) as raw materials. It was applied to maintain the suspension stability of cement slurry at ultra-high temperatures. The molecular structure and molecular weight of LHAP were characterized and tested using infrared spectroscopy, nuclear magnetic hydrogen spectroscopy, and Ubbelohde viscometer. The thermal stability and viscosity-temperature performance of LHAP were measured using thermogravimetric analysis and rheometer, respectively. Through the segmented density difference testing of cement stone columns, the suspension stability effect of LHAP on cement slurry under high temperature was evaluated. The suspension stabilization mechanism of LHAP was studied through fluorescence probe testing, variable temperature UV visible light testing, variable temperature particle size distribution testing, Zeta potential analysis, Environmental Scanning Electron Microscopy (ESEM) analysis, and scanning electron microscopy (SEM) analysis. The results indicated that the polymer suspension agent LHAP had excellent temperature resistance, and the molecules didn’t undergo significant thermal degradation below 302 ℃. At high temperatures of 220 ℃, LHAP could maintain the suspension stability of cement slurry, and the segmented density difference of cement columns was less than 0.01 g/cm3. Mechanism analysis revealed that in addition to enhancing temperature resistance by introducing sulfonic acid groups and rigid rings, LHAP also effectively maintains the stability of the slurry suspension at ultra-high temperatures by coordinating electrostatic interactions and molecular associations. LHAP can effectively solve the settlement instability problem of cement slurry under ultra-high temperature, which is beneficial for improving the safety and quality of cementing construction in ultra-deep wells.

Regional (economic) integration, political stability uncertainty and (intra-African) exports

The economic literature reports ambiguous effects of regional economic integration (REI) and political stability on exports. Therefore, this research analyzes the effects of REI and political stability on intra-African exports, compares them to the effects on intra-African imports and explores the combined effect of REI and political stability on intra-African exports. We use the two-stage least squares and fixed-effects approach which includes the two-step feasible generalized method of moments (GMM) estimation to address endogeneity issues in a panel of 49 African countries over the period of 1996–2022. The results show that REI and political stability lead to an increase in intra-African exports. However, while REI results in an increase in intra-African imports, political stability results in a decrease; similar findings are highlighted for overall intra-African trade as well as for total exports of goods and services. The results remain robust across diverse estimation techniques. Furthermore, they reveal that political stability plays a role in amplifying the relationship between REI and intra-African exports. Supporting the African Continental Free Trade Area agenda, these findings imply that African policymakers need to (i) strengthen REI to increase intra-African trade and (ii) improve political stability to ensure that a greater part of REI is canalized in a more effective way in order to boost intra-African exports.

Effect of Ozonation on Physicochemical Properties of Olive Oil Based Sunscreen Product

ABSTRACT Ozone serves as a potent oxidizing agent and a universal antiseptic, extensively employed in industries such as food, pharmaceuticals, and cosmetics due to its ability to dissolve in water and decompose into oxygen. This study aimed to treat virgin olive oil (VOO) with the ozonation process prior to its incorporation into a sunscreen product, and to discover any new potentially useful properties by comparing it with a sunscreen containing non-ozonated olive oil. The comparison was based on physicochemical properties, physical appearance, and sun protection factor (SPF) value. VOO treated with 0.017 mole/L ozone was tested for various physicochemical properties such as color, viscosity, refractive index, acid value, iodine value, peroxide value, saponification value, and oxidative stability. The composition was analyzed using gas chromatography (GC) and gas chromatography – mass spectrometry (GC-MS). The properties of ozonated olive oil (OOO) differed from VOO in terms of viscosity and flow behavior. An increase in shear rate significantly reduced the viscosity of OOO, while VOO maintained a constant viscosity and exhibited Newtonian flow behavior. When OOO was incorporated into sunscreen products, it enhanced the spreadability of the product on the skin, resulting in a significantly higher SPF value. The ability of a sunscreen to spread evenly on the skin and form a continuous thin film is crucial for effective protection against the sun’s rays. These findings highlight the potential of OOO in enhancing the photoprotection efficacy of sunscreen products by providing valuable data for its incorporation into formulations aiming to improve sun protection. Future research could focus on long-term stability and potential side effects of OOO in cosmetic formulations.