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1.
Carbohydr Polym ; 343: 122432, 2024 Nov 01.
Article in English | MEDLINE | ID: mdl-39174119

ABSTRACT

Sorption is one of the most efficient methods to remediate the increasing oil spill incidents, but the currently available absorbents are inadequate to tackle such a global threat. Recently, numerous researchers have attempted to develop sustainable oil sorbents. Cellulose aerogels and foams, a type of lightweight porous material with excellent sorption performance, are one of the most promising candidates. Significant progress has been made in the past decade towards the development of cellulose porous materials as effective oil sorbents, with improvements in their oil sorption capacity, reusability, and enhanced multifunctionality, indicating their potential for oil spill remediation. This article reviews recent reports and provides a comprehensive overview of the preparation and modification strategies for cellulose porous materials, with a specific emphasis on their oil sorption performance and structure control. We also focus on the burgeoning 3D printing technology within this field, summarizing the latest advances with a discussion of the potential for using 3D printing to customize and optimize the structure of cellulose porous materials. Lastly, this review addresses current limitations and outlines future directions for development.

2.
Heliyon ; 10(15): e34765, 2024 Aug 15.
Article in English | MEDLINE | ID: mdl-39144965

ABSTRACT

Failures in mining machinery can abruptly halt mineral production and operations, emphasizing the indispensable role of humans in maintenance and repair operations. Addressing human errors is crucial for ensuring a safe and reliable system, particularly during maintenance activities where accidents frequently occur. This paper focuses on evaluating Human Reliability (HR) to enhance activity implementation effectiveness. Given the challenge of limited and uncertain data on human errors, this study aims to estimate the probability of human errors using Bayesian networks (BN) under uncertain parameters. Applying this approach to assess HR in the maintenance and repair operations of mining trucks at Golgohar Iron Ore Mine in Iran, the study identifies critical factors influencing error occurrence in a fuzzy environment. The results highlight key factors impacting human error and offer insights into estimating HR with minimal human intervention.

3.
Acta Neurol Belg ; 2024 Aug 15.
Article in English | MEDLINE | ID: mdl-39147996

ABSTRACT

Developmental and epileptic encephalopathy type 25 with amelogenesis imperfecta (DEE25) is a rare autosomal recessive disorder caused by homozygous or compound heterozygous disease-causing variants in the SLC13A5. These variants can disrupt energy production and delay brain development, leading to DEE25. Key symptoms include refractory seizures, often manifesting in neonates or infants, alongside global developmental delay, intellectual disability, progressive microcephaly, ataxia, spasticity, and speech difficulties. Dental anomalies related to amelogenesis imperfecta are common. Previous studies have typically reported normal or minimally altered early-life brain magnetic resonance imaging (MRI) findings in DEE25. However, our investigation identified a homozygous splice donor variant (NM_177550.5: c.1437 + 1G >T) in SLC13A5 through whole-exome sequencing in two affected siblings (P1 and P2). They displayed developmental delay, cerebral hypotonia, speech delay, recurrent seizures, mild but constant microcephaly, and motor impairments. Significantly, P1 exhibited novel findings on brain magnetic resonance imaging at age 5, including previously unreported extensive persistent hypomyelination. Meanwhile, P2 showed substantial loss of cerebral white matter in the frontoparietal region and delayed myelination at 18 months old. These discoveries broaden the DEE25 imaging spectrum and highlight the clinical heterogeneity even within siblings sharing the same variants.

4.
Int J Bipolar Disord ; 12(1): 30, 2024 Aug 20.
Article in English | MEDLINE | ID: mdl-39162912

ABSTRACT

BACKGROUND: Current treatments for bipolar depression have limited effectiveness, tolerability and acceptability. Transcranial direct current stimulation (tDCS) is a novel non-invasive brain stimulation method that has demonstrated treatment efficacy for major depressive episodes. tDCS is portable, safe, and individuals like having sessions at home. We developed a home-based protocol with real-time remote supervision. In the present study, we have examined the clinical outcomes, acceptability and feasibility of home-based tDCS treatment in bipolar depression. RESULTS: Participants were 44 individuals with bipolar disorder (31 women), mean age 47.27 ± 12.89 years, in current depressive episode of at least moderate severity (mean Montgomery Asberg Depression Rating Scale (MADRS) score 24.59 ± 2.64). tDCS was provided in bilateral frontal montage, F3 anode, F4 cathode, 2 mA, for 30 min, in a 6-week trial, for total 21 sessions, a follow up visit was conducted 5 months from baseline. Participants maintained their current treatment (psychotherapy, antidepressant or mood stabilising medication) or maintained being medication-free. A research team member was present by video conference at each session. 93.2% participants (n = 41) completed the 6-week treatment and 72.7% of participants (n = 32) completed the 5 month follow up. There was a significant improvement in depressive symptoms following treatment (mean MADRS 8.77 ± 5.37) which was maintained at the 5 month follow up (mean MADRS 10.86 ± 6.90), rate of clinical response was 77.3% (MADRS improvement of 50% or greater from baseline), and rate of clinical remission was 47.7% (MADRS rating of 9 or less). Acceptability was endorsed as "very acceptable" or "quite acceptable" by all participants. No participants developed mania or hypomania. CONCLUSIONS: In summary, home-based tDCS with real-time supervision was associated with significant clinical improvements and high acceptability in bipolar depression. Due to the open-label design, efficacy findings are preliminary. TRIAL REGISTRATION: ClinicalTrials.gov number NCT05436613 registered on 23 June 2022 https//www. CLINICALTRIALS: gov/study/NCT05436613.

5.
R Soc Open Sci ; 11(6): 240045, 2024 Jun.
Article in English | MEDLINE | ID: mdl-39100160

ABSTRACT

In this paper, we present a novel and sustainable approach using choline chloride:triethanolamine as a green, efficient and reusable deep eutectic solvent (DES) for Pd-catalysed O-arylation reactions with Pd/BaSO4 (10%). By using the unique properties of DESs, we successfully achieved C-O bond formation without the need for additional solvents, bases and ligands. This solvent/catalyst system ([ChCl][TEA]2) functioned as a dual catalyst and solvent system, enabling fast and environmentally friendly C-O bond formation from phenol derivatives and electron-deficient aryl halides, leading to remarkable yields under mild reaction conditions. To identify and characterize this DES, we employed differential scanning calorimetry, thermogravimetric analysis, Fourier-transform infrared spectroscopy, refractive index, viscosity, the potential of hydrogen (pH) and conductivity measurements. One of the remarkable advantages of this DES system is its exceptional stability. This solvent/catalyst system exhibited high stability throughout the reaction cycles, showing no significant loss of activity. As a result, this DES and catalyst (Pd/BaSO4 (10%)) can be easily recycled and re-used for up to three consecutive cycles, making it an economically and environmentally attractive option for organic reactions. Our approach offers several key benefits, including simple catalyst preparation, quick reaction times and excellent production efficiency.

6.
Mol Biol Rep ; 51(1): 913, 2024 Aug 17.
Article in English | MEDLINE | ID: mdl-39153108

ABSTRACT

Klotho is recognized as an aging-suppressor protein that is implicated in a variety of processes and signaling pathways. The anti-inflammatory, anti-apoptotic, anti-oxidant, and anti-tumor bioactivities of klotho have extended its application in neurosciences and made the protein popular for its lifespan-extending capacity. Furthermore, it has been demonstrated that klotho levels would reduce with aging and numerous pathologies, particularly those related to the central nervous system (CNS). Evidence supports the idea that klotho can be a key therapeutic target in CNS diseases such as amyotrophic lateral sclerosis, Parkinson's disease, stroke, and Alzheimer's disease. Reviewing the literature suggests that the upregulation of klotho expression regulates various signaling pathways related to autophagy, oxidative stress, inflammation, cognition, and ferroptosis in neurological disorders. Therefore, it has been of great interest to develop drugs or agents that boost or restore klotho levels. In this regard, the present review was designed and aimed to gather the delegated documents regarding the therapeutic potential of Klotho in CNS diseases focusing on the molecular and cellular mechanisms.


Subject(s)
Central Nervous System Diseases , Klotho Proteins , Signal Transduction , Humans , Central Nervous System Diseases/metabolism , Central Nervous System Diseases/drug therapy , Animals , Oxidative Stress , Glucuronidase/metabolism , Glucuronidase/genetics , Autophagy , Aging/metabolism , Aging/genetics
7.
J Chromatogr A ; 1733: 465216, 2024 Jul 29.
Article in English | MEDLINE | ID: mdl-39154493

ABSTRACT

Bio-separation is a crucial process in biotechnology and biochemical engineering for separating biological macromolecules, and the field has long relied on bead-based and expanded bed chromatography. Printed monolith adsorption (PMA) is a new alternative to which uses a 3D-printed monolithic structure containing self-supporting, ordered flow channels. PMA allows for direct purification of biological molecules from crude cell lysates and cell cultures, and like the other technologies, can functionalized to specifically target a molecule and enable affinity chromatography. Here we have combined PMA technology with an immobilized metal affinity ligand (iminodiacetic acid) to provide selectivity of binding to polyhistidine-tagged proteins during PMA chromatography. Two different PMA structures were created and tested for both static and dynamic protein-binding capacity. At comparative linear flow rates, the dynamic binding capacity of both columns was ≈3 mg/mL, while static capacity was shown to differentiate based on column voidage. We show that a polyhistidine-tagged protein can be directly purified from crude lysate with comparable results to the available commercial providers of IMAC, and with a substantially reduced purification time.

9.
Br J Anaesth ; 2024 Aug 01.
Article in English | MEDLINE | ID: mdl-39095238

ABSTRACT

BACKGROUND: Centralisation of perioperative care for small children to a limited number of specialised paediatric centres has many theoretical advantages, but neither the optimal balance nor the current distribution of paediatric anaesthesia on a national scale are well elucidated. The aim of this study was to describe the distribution, adverse events, and mortality in children undergoing anaesthesia in Sweden. METHODS: In this cohort study, data from all paediatric anaesthesia procedures registered in Sweden during the years 2019-22 were extracted from the Swedish Perioperative Register (SPOR). Data were analysed according to hospital level of care and ASA physical status. RESULTS: Data from 81 hospitals were analysed. During the 4-yr period, 214,964 procedures were registered. Most procedures in neonates and infants were managed in paediatric (73%) and other university hospitals (21%). Adverse events occurred in 2.71% of cases and severe adverse events in 0.067%. The all-cause 24-h mortality rate was 6.6:10,000 anaesthetics and the all-cause 30-day mortality was 14.7:10,000 anaesthetics. The 30-day all-cause estimated mortality was highest in paediatric hospitals (95% confidence interval [CI] 30-39) compared with other university hospitals (95% CI 6.1-12), county (95% CI 1.9-4.8), district (95% CI 0.07-2.2), and smaller hospitals (95% CI 0.0-22). CONCLUSIONS: Most procedures in neonates and infants were performed in tertiary centres, with county hospitals managing mainly older children, in accordance with national recommendations. Mortality was more common in tertiary centres, reflecting increased comorbidity and centralisation of anaesthesia of neonates and infants.

10.
Trials ; 25(1): 518, 2024 Aug 01.
Article in English | MEDLINE | ID: mdl-39090754

ABSTRACT

BACKGROUND: Heart failure is a chronic and progressive disease where the heart muscle is unable to pump enough blood and oxygen to meet the body's needs. Oxidative stress and inflammation are key elements in the development and progression of heart failure. Astaxanthin, a carotenoid, has strong anti-inflammatory and antioxidant effects that may protect the cardiovascular system. A study will evaluate the effect of astaxanthin supplementation on inflammatory status, oxidative stress, lipid profile, uric acid levels, endothelial function, quality of life, and disease symptoms in people with heart failure. METHODS: The current study is a double-blind controlled randomized clinical trial for 8 weeks, in which people with heart failure were randomly assigned to two groups: intervention (one capsule containing 20 mg of astaxanthin per day, n = 40) and placebo (one capsule containing 20 mg of maltodextrin per day, n = 40) will be divided. At the beginning and end of the intervention, uric acid, lipid profile, oxidative stress indices, inflammatory markers, blood pressure, nitric oxide, and anthropometric factors will be measured, and questionnaires measuring quality of life, fatigue intensity, shortness of breath, and appetite will be completed. SPSS version 22 software will be used for statistical analysis. DISCUSSION: There is a growing global interest in natural and functional food products. This RCT contributes to the expanding body of research on the potential benefits of astaxanthin in heart failure patients, including its antioxidant, lipid-lowering, and anti-inflammatory effects. TRIAL REGISTRATION: Iranian Registry of Clinical Trials IRCT20200429047235N3. Registered on 26 March 2024.


Subject(s)
Biomarkers , Blood Pressure , Dietary Supplements , Heart Failure , Oxidative Stress , Quality of Life , Uric Acid , Xanthophylls , Humans , Xanthophylls/therapeutic use , Oxidative Stress/drug effects , Heart Failure/drug therapy , Heart Failure/physiopathology , Heart Failure/blood , Uric Acid/blood , Double-Blind Method , Biomarkers/blood , Blood Pressure/drug effects , Randomized Controlled Trials as Topic , Middle Aged , Male , Lipids/blood , Female , Antioxidants , Aged , Treatment Outcome , Inflammation Mediators/blood , Adult , Inflammation/blood , Anti-Inflammatory Agents/therapeutic use , Iran
11.
Mater Today Bio ; 27: 101134, 2024 Aug.
Article in English | MEDLINE | ID: mdl-39027676

ABSTRACT

Biomimetic functionalized metal-organic frameworks (Fn-MOFs) represent a cutting-edge approach in the realm of cancer vaccines. These multifunctional agents, inspired by biological systems, offer unprecedented opportunities for the development of next-generation cancer vaccines. The vast surface area, tunable pore size, and diverse chemistry of MOFs provide a versatile scaffold for the encapsulation and protection of antigenic components, crucial for vaccine stability and delivery. This work delves into the innovative design and application of Fn-MOFs, highlighting their role as carriers for immune enhancement and their potential to revolutionize vaccine delivery. By mimicking natural processes, Fn-MOFs, with their ability to be functionalized with a myriad of chemical and biological entities, exhibit superior biocompatibility and stimuli-responsive behavior and facilitate targeted delivery to tumor sites. This review encapsulates the latest advancements in Fn-MOF technology, from their synthesis and surface modification to their integration into stimuli-responsive and combination therapies. It underscores the significance of biomimetic approaches in overcoming current challenges in cancer vaccine development, such as antigen stability and immune evasion. By leveraging the biomimetic nature of Fn-MOFs, this work paves the way for innovative strategies in cancer vaccines, aiming to induce potent and long-lasting immune responses against malignancies.

12.
J Biomed Phys Eng ; 14(3): 309-314, 2024 Jun.
Article in English | MEDLINE | ID: mdl-39027707

ABSTRACT

Humans have generally evolved some adaptations to protect against UV and different levels of background ionizing radiation. Similarly, elephants and whales have evolved adaptations to protect against cancer, such as multiple copies of the tumor suppressor gene p53, due to their large size and long lifespan. The difference in cancer protection strategies between humans and elephants/whales depends on genetics, lifestyle, environmental exposures, and evolutionary pressures. In this paper, we discuss how the differences in evolutionary adaptations between humans and elephants could explain why elephants have evolved a protective mechanism against cancer, whereas humans have not. Humans living in regions with high levels of background radiation, e.g. in Ramsar, Iran where exposure rates exceed those on the surface of Mars, seem to have developed some kind of protection against the ionizing radiation. However, humans in general have not developed cancer-fighting adaptations, so they instead rely on medical technologies and interventions. The difference in cancer protection strategies between humans and elephants/whales depends on genetics, lifestyle, environmental exposures, and evolutionary pressures. In this paper, we discuss how the differences in evolutionary adaptations between humans and elephants could explain why elephants have evolved a protective mechanism against cancer, whereas humans have not. Studying elephant adaptations may provide insights into new cancer prevention and treatment strategies for humans, but further research is required to fully understand the evolutionary disparities.

13.
J Biomed Phys Eng ; 14(3): 319-322, 2024 Jun.
Article in English | MEDLINE | ID: mdl-39027714

ABSTRACT

Professor John Roderick Cameron (1922-2005) stands out as a trailblazer in the field of medical physics, whose innovative work has deeply influenced radiation protection and the broader medical radiation field through sound technical judgment and insight. Best known for inventing the bone densitometry device, his pioneering efforts have reshaped modern medical practices far beyond his initial breakthroughs. Cameron's explorations extended into the realms of space biomedical science and models of terrestrial radiation, areas where his insights continue to resonate today. As the Emeritus Professor of Medical Physics at the University of Wisconsin-Madison and a founding member of the American Association of Physicists in Medicine, Cameron laid crucial groundwork for safety standards in environments with high natural radiation levels. His leadership was instrumental in advancing thermoluminescence dosimetry, radiation measurement, and image quality assurance, driving progress in both academia and clinical practices. Moreover, through establishing Medical Physics Publishing, Cameron played a pivotal role in spreading vital research and educational materials across the fields of health physics and medical physics. This commentary reflects on Cameron's far-reaching contributions, highlighting his critical work in space radiation research and terrestrial radiation models-key to the future of interplanetary travel and potential human settlement on planets like Mars. His research in areas of high background radiation, like Ramsar, Iran, has been fundamental in developing strategies for biological protection in space, which are essential for ensuring astronaut safety during long-duration space missions. We honor Professor Cameron's profound legacy, celebrating his visionary spirit and the lasting impact of his contributions on generations of scientists in radiation science.

14.
Heliyon ; 10(12): e32813, 2024 Jun 30.
Article in English | MEDLINE | ID: mdl-39005921

ABSTRACT

Large-amplitude plasma wave is known to accelerate electrons to high energies. The electron energy gain mainly depends on plasma wave amplitude. In this paper, we investigate the excitation of large-amplitude plasma waves by laser beat-wave in an inhomogeneous plasma. The idea behind this work is to employ linear and radial plasma density profiles to enhance the plasma wave amplitude. PIC simulations are used to validate the numerical solution of the nonlinear wave equation in cylindrical dimensions through the finite difference method. Furthermore, the effects of the quadratic-radial plasma density profiles and magnetic field on the plasma wave excitation are investigated. The study shows that compared to the linear density profile of plasma, the plasma wave amplitude in the case of a linear-radial density profile is far more pronounced. For the linear-radial density profile, the plasma wave amplitude remains steady over greater distances of propagation compared to the linear density profile, resulting in reduced immediate damping effects. It can also be seen that the plasma wave amplitude is higher for the quadratic-radial than for the linear-radial density profiles. The effect of a longitudinal magnetic field on plasma wave amplitude is investigated. It can be seen that the plasma wave amplitude is increased by applying a magnetic field. This study may provide a way to enhance the plasma wave field for accelerating the electrons in laser-plasma accelerators.

15.
BMC Public Health ; 24(1): 1875, 2024 Jul 15.
Article in English | MEDLINE | ID: mdl-39004703

ABSTRACT

BACKGROUND: Underweight is a prevalent health issue in children. This study aimed to identify factors associated with underweight in children aged 1-2 years in Hamadan city. Unlike the studies conducted in this field, which are cross-sectional and do not provide information on the effect of age changes on underweight, our longitudinal approach provides insights into weight changes over time. On the other hand, this study focuses on the high-risk age group of 1 to 2 years, which has only been addressed in a few studies. METHODS: In this longitudinal study, 414 mothers with 1 to 2 year-old children referred to the health centers of Hamadan city, whose information is in the SIB system, a comprehensive electronic system, were examined to identify factors related to underweight. The response variable was weight-for-age criteria classified into three categories: underweight, normal weight, and overweight. A two-level longitudinal ordinal model was used to determine the factors associated with underweight. RESULTS: Of the children studied, 201 (48.6%) were girls and 213 (51.4%) were boys. Significant risk factors for underweight included low maternal education (AOR = 3.56, 95% CI: 1.10-11.47), maternal unemployment (AOR = 3.38, 95% CI: 1.05-10.91), maternal height (AOR = 0.85, 95% CI: 0.79-0.92), lack of health insurance (AOR = 2.85, 95% CI: 1.04-7.84), gestational age less than 24 years (AOR = 3.17, 95% CI: 16.28-0.97), child age 12-15 months (AOR = 2.27, 95% CI: 1.37-3.74), and child's birth weight (AOR = 0.63, 95% CI: 0.70-0.58). CONCLUSION: Based on the results of the present study, it seems that the possibility of being underweight among children is more related to the characteristics of mothers; therefore, taking care of mothers can control some of the weight loss of children.


Subject(s)
Thinness , Humans , Thinness/epidemiology , Female , Longitudinal Studies , Male , Infant , Risk Factors , Child, Preschool , Adult , Mothers/statistics & numerical data
16.
Tissue Cell ; 89: 102462, 2024 Aug.
Article in English | MEDLINE | ID: mdl-39002289

ABSTRACT

Successful treatment of diabetic wounds requires multifactorial approaches. Herein we investigated the effects of a bioengineered three-dimensional dermal derived matrix-scaffold (DMS) in combination with hyperbaric oxygen (HBO) in repairing of wound model in diabetic rats. Thirty days after induction of diabetes, a circular wound was created and treatments were performed for 21 days. Animals were randomly allocated into the untreated group, DMS group, HBO group, and DMS+HBO group. On days 7, 14, and 21, tissue samples were obtained for stereological, molecular, and tensiometrical assessments. Our results showed that the wound closure rate, volume of new dermis and epidermis, numerical density fibroblasts and blood vessels, collagen density, and biomechanical characterize were significantly higher in the treatment groups than in the untreated group, and these changes were more obvious in the DMS+HBO ones. Moreover, the expression of TGF-ß, bFGF, miRNA-21, miRNA-146a, and VEGF genes were meaningfully upregulated in treatment groups compared to the untreated group and were greater in the DMS+HBO group. This is while expression of TNF-α and IL-1ß, as well as the numerical density of neutrophil and macrophage decreased more considerably in the DMS+HBO group than in the other groups. Overall, using both DMS engraftment and HBO treatment has more effects on diabetic wound healing.


Subject(s)
Diabetes Mellitus, Experimental , Hyperbaric Oxygenation , Tissue Scaffolds , Wound Healing , Animals , Diabetes Mellitus, Experimental/therapy , Diabetes Mellitus, Experimental/pathology , Rats , Tissue Scaffolds/chemistry , Male , Rats, Sprague-Dawley
17.
Sci Rep ; 14(1): 17584, 2024 Jul 30.
Article in English | MEDLINE | ID: mdl-39080333

ABSTRACT

The dynamic analysis of municipal solid waste (MSW) is essential for optimizing landfills and advancing sustainable development goals. Assessing damping ratio (D), a critical dynamic parameter, under laboratory conditions is costly and time-consuming, requiring specialized equipment and expertise. To streamline this process, this research leveraged several novel ensemble machine learning models integrated with the equilibrium optimizer algorithm (EOA) for the predictive analysis of damping characteristics. Data were gathered from 153 cyclic triaxial experiments on MSW, which examined the age, shear strain, weight, frequency, and percentage of plastic content. Analysis of a correlation heatmap indicated a significant dependence of D on shear strain within the collected MSW data. Subsequently, five advanced machine learning methods-adaptive boosting (AdaBoost), gradient boosting regression tree (GBRT), extreme gradient boosting (XGBoost), random forest (RF), and cubist regression-were employed to model D in landfill structures. Among these, the GBRT-EOA model demonstrated superior performance, with a coefficient of determination (R2) of 0.898, root mean square error of 1.659, mean absolute error of 1.194, mean absolute percentage error of 0.095, and an a20-index of 0.891 for the test data. A Shapley additive explanation analysis was conducted to validate these models further, revealing the relative contributions of each studied variable to the predicted D-MSW. This holistic approach not only enhances the understanding of MSW dynamics but also aids in the efficient design and management of landfill systems.

18.
Electrophoresis ; 2024 Jul 30.
Article in English | MEDLINE | ID: mdl-39076068

ABSTRACT

In this study, magnetic graphene oxide coated with poly(8-hydroxyquinoline) was successfully synthesized, characterized, and utilized as a novel sorbent for the ultrasonic-assisted dispersive magnetic solid-phase extraction of naproxen and ibuprofen. These analytes served as representative analytes for two nonsteroidal anti-inflammatory drugs in various real samples. Characterization techniques, such as IR, X-ray powder diffraction, field emission scanning electron microscopy, energy-dispersive X-ray-mapping, and Brunauer-Emmett-Teller (BET), were used to confirm the correctness synthesis and preparation of the nanocomposites. Effective parameters on the extraction efficiency were investigated to maximize the analytical performance of the developed method. The dynamic range (1-1000 µg L-1), coefficients of determination (R2 ≥ 0.997), the limits of detection (0.3-1.0 µg L-1), and limit of quantification (1.0-3.0 µg L-1), intra-day and inter-day precisions (3.5%-7.2%) were achieved. The method validation results showed extraction recovery ranging from 80.4% to 96.0% and preconcentration factors ranging from 137 to 140.

19.
ACS Appl Mater Interfaces ; 16(32): 42687-42703, 2024 Aug 14.
Article in English | MEDLINE | ID: mdl-39082691

ABSTRACT

In this paper, we develop high aspect ratio nanofibrils from a polycaprolactone-based thermoplastic polyurethane (TPU) and evaluate their performance as a toughening agent. Poly(methyl methacrylate) (PMMA) was chosen as the matrix material because of its inherent brittleness and low resistance to sudden shocks and impact. We show that the addition of as little as 3 wt % of TPU nanofibrils with an average diameter of ∼98 nm and very high aspect ratio can significantly improve both the tensile toughness (∼212%) and impact strength (∼40%) of the chosen matrix (i.e., PMMA) without compromising its original strength, stiffness, and transparency. We compare the performance of TPU nanofibrils with TPU spherical particles─the form TPU typically manifests into when melt-mixed with an immiscible polymer. Our findings highlight that the structure of TPU plays a crucial role in determining the critical concentration of TPU needed for the brittle-ductile transition of the matrix. We also provide new and valuable insights into the unique interfacial interaction (i.e., formation of fibrillar bridges) observed between the PMMA matrix and TPU. We also show that the inclusion of 3 wt % of TPU nanofibrils can notably enhance resistance to creep deformation, even at temperatures close to the glass transition temperature of the matrix. Finally, we evaluate recyclability and demonstrate that the composite containing 3 wt % of TPU nanofibrils can be mechanically recycled without losing any properties. The proposed TPU nanofibrils can withstand repeated reprocessing at temperatures up to 190 °C due to their very high melting point and thermal stability. This presents the opportunity for them to be utilized not just with amorphous PMMA, but also with a range of other materials that can be processed at or below this temperature to remarkably improve their toughness without sacrificing strength and stiffness.

20.
RSC Adv ; 14(30): 21954-21970, 2024 Jul 05.
Article in English | MEDLINE | ID: mdl-38993503

ABSTRACT

A nitrilotriacetic acid (NTA) complex of Cu(ii) supported on silica-coated nanosized magnetite Fe3O4@SiO2-Pr-DEA-[NTA-Cu(ii)]2 was prepared as a new well-defined magnetically separable nanomaterial and fully characterized via IR, XRD, FESEM, TEM, TGA, DLS, BET, VSM, solid-state UV-vis spectroscopy, EDX, ICP-OES, and FESEM-EDX map analyses. Thereafter, it was successfully applied as a new easily magnetically separable and reusable heterogeneous nanocatalyst for the Buchwald-Hartwig C-N bond formation reaction in DMF at 110 °C. Using this method, various kinds of nitrogen heterocycles, such as imidazoles, 2-methyl-1H-imidazole, benzimidazole, indole, and 10H-phenothiazine as well as aliphatic secondary amines such as piperidine, piperazine, morpholine, dimethylamine, and diethylamine, were reacted with aryl halide compounds, and the desired products were obtained with good to excellent yields. In all cases, the applied catalyst could be recovered easily and rapidly using an external magnet and reused 7 times without significant loss of catalytic activity.

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