Hasil untuk "Chemical engineering"

Christy Liu, Yingzi Li, Xiaohua Liu et al.

Carbon dots (CDs) are a class of nanobiomaterials with significant potential in bone regeneration. Their excellent biocompatibility, tunable fluorescence, high stability, low toxicity, and abundant functional groups make CDs promising candidates for efficient drug delivery and bone tissue regeneration. CDs contribute to targeted drug release, enhance osteogenic differentiation, and interact with cellular components to facilitate bone formation. Recent research highlights the roles of CDs in scaffold-based approaches, offering controlled drug delivery and real-time bioimaging capabilities. This review provides a comprehensive overview of CDs in bone regeneration, with a focus on their synthesis, functionalization, and biomedical applications. It begins by exploring CD synthesis methods, physicochemical properties, and mechanisms of action. Next, it discusses CD-based drug delivery systems and their applications in bone regeneration. Finally, the review highlights the challenges and future perspectives in optimizing CDs for enhanced therapeutic outcomes.

Xin Guan, Yang Liu, Lianwei Li et al.

Abstract Particle assembly at liquid–liquid interfaces presents a promising bottom‐up strategy for creating supramolecular materials with advanced functionalities. However, the significantly lower interfacial tension observed in immiscible organic phases compared to traditional oil–water systems has hindered the effective adsorption and assembly of particles at oil–oil interfaces. In this work, a versatile and effective strategy is presented that utilizes the assembly and jamming of microgels and polymer ligands at non‐aqueous liquid–liquid interfaces to create non‐aqueous Pickering emulsions and reconfigurable droplet networks. The resulting microgel‐polymer complexes form an asymmetric interfacial bilayer with high surface coverage, which effectively minimizes interfacial energy and improves interfacial elasticity. Through a combination of systematic interfacial measurements and molecular dynamics simulations, the underlying mechanisms governing interfacial self‐assembly are elucidated. Notably, the stimuli‐responsive nature of the microgel‐polymer complexes allows for precise control over the interfacial assembly and disassembly by introducing competitive molecules. Furthermore, it is demonstrated that these non‐aqueous Pickering emulsions serve as excellent templates for the fabrication of heterogeneous organogels and microgel‐based colloidosomes through both covalent and non‐covalent crosslinking strategies. This work underscores the potential of non‐aqueous interfaces in advancing materials science and opens new avenues for developing multifunctional materials.

The Truyen Tran, Thu Minh Tran, Xuan Tung Nguyen et al.

This study aims to present the results of anticipation of lightweight concrete durability when exposed to a chloride environment under pre-compressive load. The research employs Keramzit aggregate as the coarse aggregate for lightweight concrete. Following a 28-day curing period in water, the concrete specimens undergo varying levels of pre-compressive stress. Rapid Chloride Permeability Testing is then conducted to ascertain the chloride diffusion coefficient. The study posits a correlation between the chloride diffusion coefficient and precompressive stress levels, drawing from the experimental findings. Furthermore, Monte-Carlo simulation is employed to assess the influence of stochastic variables on the corrosion likelihood of concrete structures using lightweight aggregates. These stochastic variables encompass the chloride diffusion coefficient, surface chloride concentration, critical chloride concentration, concrete protection layer thickness, and a coefficient contingent on environmental conditions, to appraise the operational lifespan of lightweight concrete structures.

Seyed Jamaleddin Peighambardoust, Shima Abdollahian Aghbolagh, Rauf Foroutan et al.

Abstract This study investigates the use of pine cones as a novel and readily available precursor for producing biochar (BC), which is then modified with CoFe2O4 magnetic nanoparticles and Mn-Fe layered double hydroxide (LDH) to enhance its adsorption capacity for removing the cationic dye crystal violet (CV) from aqueous solutions. The physical and chemical properties of the resulting adsorbents—BC (BCPC), BC/CoFe2O4, and BC/CoFe2O4/Mn-Fe LDH—were characterized using FTIR, XRD, VSM, SEM, EDX mapping, and BET analyses. BET results revealed that the specific surface areas of BCPC, BCPC/CoFe2O4, and BCPC/CoFe2O4/Mn-Fe LDH were 43.41, 95.81, and 98.85 m2/g, respectively, indicating a significant enhancement in surface area due to modification. Additionally, the magnetic saturation of the BCPC/CoFe2O4/Mn-Fe LDH composite was 32.35 emu/g, confirming that the composite could be easily separated from the solution using an external magnetic field. The composite achieved a maximum CV dye removal efficiency of 98.54% under optimal conditions: pH = 9, temperature 25 °C, adsorbent dose of 1 g/L, contact time of 70 min, and initial dye concentration of 10 mg/L. Isotherm studies revealed that the Langmuir model provided the best fit for the experimental data, suggesting a monolayer adsorption process on homogeneous surfaces. Kinetic studies indicated that the pseudo-second-order model was the most appropriate, highlighting the importance of chemical interactions in the adsorption process. Thermodynamic analyses revealed that the adsorption process was exothermic and spontaneous, as confirmed by negative enthalpy (∆H°) and Gibbs free energy (∆G°) values. In contrast, the negative entropy (∆S°) indicated a reduction in randomness during adsorption. This study demonstrates that the BCPC/CoFe2O4/Mn-Fe LDH magnetic nanocomposite is an effective, sustainable, and easily separable adsorbent for removing cationic dyes from aqueous environments.

Armin Abbasi, Jafar Towfighi Darian, Mahdi Pourmand et al.

The methanol-to-olefins (MTO) process is a key catalytic route for light olefin production, yet challenges related to catalyst deactivation and coke formation persist. In this study, we investigate the catalytic performance of SAPO-34 (SP) and a modified SAPO-34 catalyst incorporating a mixed metal oxide of indium oxide and cerium oxide (SPM) to enhance selectivity, stability, and coke resistance. A combination of experimental and theoretical approaches, including catalyst characterization, MTO catalytic testing, and molecular dynamics (MD) simulations, was employed to elucidate the impact of mixed metal oxide incorporation on catalyst properties. The results indicate that SPM exhibits significantly higher total olefin selectivity (85.7 %) compared to SP (76.6 %), with improved stability and a catalytic lifetime approximately twice as long. Furthermore, SPM demonstrates a higher propylene-to-ethylene (P/E) ratio, reaching 2.9 at the initial stage compared to 1.5 for SP. The incorporation of mixed metal oxides enhances mesoporosity and modifies acid site distribution, reducing excessive secondary reactions and mitigating coke formation. MD simulations confirm that SPM inhibits the formation of formaldehyde species, a key coke precursor, while promoting coke oxidation, thereby extending catalyst lifespan. These findings suggest that mixed metal oxide incorporation is an effective strategy for optimizing SAPO-34-based catalysts for sustainable MTO applications.

Colten L. Snider, Chris J. Glover, David A. Grant et al.

Three-dimensional printing provides more versatility in the fabrication of scaffold materials for hard and soft tissue replacement, but a critical component is the ink. The ink solution should be biocompatible, stable, and able to maintain scaffold shape, size, and function once printed. This paper describes the development of a collagen ink that remains in a liquid pre-fibrillized state prior to printing. The liquid stability occurs due to the incorporation of ethylenediaminetetraacetic acid (EDTA) during dialysis of the collagen. Collagen inks were 3D-printed using two different printers. The resulting scaffolds were further processed using two different chemical crosslinkers, 1-Ethyl-3-[3-dimethylaminopropyl]carbodiimide hydrochloride)/N-hydroxysuccinimide (EDC/NHS) and genipin; gold nanoparticles were conjugated to the scaffolds. The 3D-printed scaffolds were characterized to determine their extrudability, stability, amount of AuNP conjugated, and overall biocompatibility via cell culture studies using fibroblast cells and stroma cells. The results demonstrated that the liquid collagen ink was amendable to 3D printing and was able to maintain its 3D shape. The scaffolds could be conjugated with gold nanoparticles and demonstrated enhanced biocompatibility. It was concluded that the liquid collagen ink is a good candidate material for the 3D printing of tissue scaffolds.

Anton Peter Jacob Middelberg

Ainhoa Oller-Ruiz, Nuria Alcaraz-Oliver, Gema Férez et al.

Marine biotoxins have posed a persistent problem along various coasts for many years. Coastal lagoons are ecosystems prone to phytoplankton blooms when altered by eutrophication. The Mar Menor is the largest hypersaline coastal lagoon in Europe. Sixteen marine toxins, including lipophilic toxins, yessotoxins, and domoic acid (DA), in seawater samples from the Mar Menor coastal lagoon were measured in one year. Only DA was detected in the range of 44.9–173.8 ng L⁻¹. Environmental stressors and mechanisms controlling the presence of DA in the lagoon are discussed. As an enrichment and clean-up method, we employed solid phase extraction to filter and acidify 75 mL of the sample, followed by pre-concentration through a C18 SPE cartridge. The analytes were recovered in aqueous solutions and directly injected into the liquid chromatography system (LC-MS), which was equipped with a C18 column. The system operated in gradient mode, and we used tandem mass spectrometry (MS/MS) with a triple quadrupole (QqQ) in the multiple reaction monitoring mode (MRM) for analysis. The absence of matrix effects was checked and the limits of detection for most toxins were low, ranging from 0.05 to 91.2 ng L⁻¹, depending on the compound. To validate the measurements, we performed recovery studies, falling in the range of 74–122%, with an intraday precision below 14.9% RSD.

Jiale Qu, Junjie Liu, Guorui Leng et al.

The impressive theoretical specific capacity and negative potential of lithium have led to its status as a prime candidate for anodes in secondary lithium batteries. Lithium metal electrodes are an area of growing importance in this field. Despite the promise that lithium batteries hold, several practical issues impede their widespread use, such as short cycle life, low coulombic efficiency, and safety concerns including combustion and explosion. The growth of lithium dendrites during battery discharge is widely recognized as the cause of these problems. In this manuscript, we present a comprehensive review of current understanding and existing issues associated with lithium metal electrodes.

Zunyu Liu, Chaoyu Zhao, Shuangfeng Jia et al.

Abstract Multi-dimensional heterojunction materials have attracted much attention due to their intriguing properties, such as high efficiency, wide band gap regulation, low dimensional limitation, versatility and scalability. To further improve the performance of materials, researchers have combined materials with various dimensions using a wide variety of techniques. However, research on growth mechanism of such composite materials is still lacking. In this paper, the growth mechanism of multi-dimensional heterojunction composite material is studied using quasi-two-dimensional (quasi-2D) antimonene and quasi-one-dimensional (quasi-1D) antimony sulfide as examples. These are synthesized by a simple thermal injection method. It is observed that the consequent nanorods are oriented along six-fold symmetric directions on the nanoplate, forming ordered quasi-1D/quasi-2D heterostructures. Comprehensive transmission electron microscopy (TEM) characterizations confirm the chemical information and reveal orientational relationship between Sb2S3 nanorods and the Sb nanoplate as substrate. Further density functional theory calculations indicate that interfacial binding energy is the primary deciding factor for the self-assembly of ordered structures. These details may fill the gaps in the research on multi-dimensional composite materials with ordered structures, and promote their future versatile applications. Graphical Abstract

Md. Jamal Hossain, Foyez Ahmmed, Md. Robin Khan et al.

ObjectivesThis current study aims to assess the prevalence and factors associated with body mass index (BMI), dietary patterns, and the extent of physical activities among university students following the prolonged coronavirus disease 2019 (COVID-19) lockdown in Bangladesh.MethodsA cross-sectional web-based survey was conducted between July 10 to August 10, 2021, through a pre-designed Google Form to collect the data from Bangladeshi university students (age: ≥18 years). Informed consent was electronically obtained from each participant, and a simple snowball technique was employed during the sampling. Frequency and percentage distribution, paired t-test, chi-square [χ2] test, and multinomial and binary logistic regression analyses were consecutively applied to analyze the collected data.ResultsAmong the total participants (n = 1,602), 45.1% were female and 55.6% were 22–25 years' age group students. The BMI (mean ± standard deviation, SD) during the COVID-19 lockdown was 23.52 ± 7.68 kg/m2, which was 22.77 ± 4.11 kg/m2 during the pre-lockdown period (mean difference = 0.753; p < 0.001). The multinomial logistic regression analysis found a significant impact of gender [male vs. female: adjusted relative risk ratio (RRR) = 1.448; 95% confidence interval (CI) = 1.022, 2.053; p = 0.037], age (years) (<22 vs. >25: RRR =0.389, 95% CI = 0.213,0.710; p = 0.002, and 22–25 vs. >25: RRR = 0.473, 95% CI = 0.290, 0.772; p = 0.003), monthly family income (BDT) (<25,000 vs. >50,000: RRR = 0.525, 95% CI = 0.334,0.826; p = 0.005), university type (public vs. private: RRR = 0.540, 95% CI = 0.369, 0.791; p = 0.002), eating larger meals/snacks (increased vs. unchanged: RRR = 2.401, 95% CI = 1.597, 3.610; p < 0.001 and decreased vs. unchanged: RRR = 1.893, 95% CI = 1.218, 2.942; p = 0.005), and verbally or physically abuse (yes vs. no: RRR = 1.438, 95% CI = 0.977, 2.116; p = 0.066) on obesity during COVID-19 pandemic. Besides, the female students and those who have constant eating habits, were more likely to be underweight. Additionally, the binary logistic regression analysis found that the students from private universities [others vs. private: adjusted odds ratio (AOR) = 0.461, 95% CI = 0.313, 0.680; p < 0.001], urban areas (urban vs. rural: AOR = 1.451, 95% CI = 1.165, 1.806; p = 0.001), wealthier families (<25,000 BDT vs. >50,000 BDT: AOR = 0.727, 95% CI = 0.540, 0.979; p = 0.036), and who were taking larger meals/snacks (increased vs. unchanged: AOR = 2.806, 95% CI = 2.190, 3.596; p < 0.001) and had conflicts/arguments with others (no vs. yes: AOR = 0.524, 95% CI = 0.418, 0.657; p < 0.001), were significantly more physically inactive. Finally, the level of education and smoking habits significantly influenced the eating habits of university students during the extended strict lockdown in Bangladesh.ConclusionThe current findings would be helpful tools and evidence for local and international public health experts and policymakers to reverse these worsening effects on students mediated by the prolonged lockdown. Several effective plans, programs, and combined attempts must be earnestly implemented to promote a smooth academic and daily life.

Shijia Liu, Ayse Ay, Qiaochu Luo et al.

The integration of non-enzymatic glucose sensing entities into device designs compatible with industrial production is crucial for the broad take-up of non-invasive glucose sensors. Copper and its oxides have proven to be promising candidates for electrochemical glucose sensing. They can be fabricated in situ enabling integration with standard copper metallisation schemes for example in printed circuit boards (PCBs). Here, copper oxide electrodes are prepared on flexible polyimide substrates through direct annealing of patterned electrode structures. Both annealing temperature and duration are tuned to optimise the sensor surface for optimum glucose detection. A combination of microscopy and spectroscopy techniques is used to follow changes to the surface morphology and chemistry under the varying annealing conditions. The observed physico-chemical electrode characteristics are directly compared with electrochemical testing of the sensing performance, including chronoamperommetry and interference experiments. A clear influence of both aspects on the sensing behaviour is observed and an anneal at 250 °C for 8 h is identified as the best compromise between sensor performance and low interference from competing analytes.

Grzegorz Krasowski, Adam Junka, Justyna Paleczny et al.

Chronic wounds complicated with biofilm formed by pathogens remain one of the most significant challenges of contemporary medicine. The application of topical antiseptic solutions against wound biofilm has been gaining increasing interest among clinical practitioners and scientific researchers. This paper compares the activity of polyhexanide-, octenidine- and hypochlorite/hypochlorous acid-based antiseptics against biofilm formed by clinical strains of <i>Candida albicans, Staphylococcus aureus</i> and <i>Pseudomonas aeruginosa</i>. The analyses included both standard techniques utilizing polystyrene plates and self-designed biocellulose-based models in which a biofilm formed by pathogens was formed on an elastic, fibrinous surface covered with a fibroblast layer. The obtained results show high antibiofilm activity of polihexanide- and octenidine-based antiseptics and lack or weak antibiofilm activity of hypochlorite-based antiseptic of total chlorine content equal to 80 parts per million. The data presented in this paper indicate that polihexanide- or octenidine-based antiseptics are highly useful in the treatment of biofilm, while hypochlorite-based antiseptics with low chlorine content may be applied for wound rinsing but not when specific antibiofilm activity is required.

Harwoko Harwoko, Jungho Lee, Georgios Daletos et al.

Background: Genus Trichoderma of fungal kingdom are largely used as biological control agents due to broad-spectrum activity against plant pathogens. Objective: This study aimed to investigate Trichoderma harzianum, an endophytic fungus obtained from ginger (Zingiber officinale) leaves. Methods: The chemical structures of the isolated compounds were deduced on the basis of UV, 1H NMR and MS data analyses, as well as comparison with literature. Results: Two known tetramic acid derivatives were isolated from this fungus, including harzianic acid (A) and isoharzianic acid (B). Compound B inhibited the growth of a corn pathogenic fungus, Ustilago maydis, with inhibition zone diameter (39 ± 0.33 mm) larger than nystatin (29 mm). Additionally, iso-HA (B) revealed antibacterial effect towards Staphylococcus aureus with MIC value of 25 µM. However, both compounds showed no cytotoxicity against human cervical and ovarian cancer cell lines. Conclusion: T. harzianum produced antimicrobial compound like iso-HA which has potential application either in agricultural or health.

Maral Rahimzadeh, Majid Sadeghizadeh, Farhood Najafi et al.

During the last few decades, extensive studies have been conducted to elucidate the anti-cancer effects of curcumin. Despite promising results indicating curcumin could impede cancer cells ability thrive and proliferation, clinical applications of it have been limited. This limitation is mainly due to low solubility, poor bioavailability, rapid metabolism, and deficient absorption. To improve the physiochemical properties of curcumin, we have synthesized a novel biodegradable gemini surfactant in which curcumin molecules were entrapped. Gemini surfactant-curcumin nanocapsules were prepared using nanoprecipitation method and characterized by several techniques including, DLS, TEM, AFM, FTIR, DSC and XRD. The in vitro MTT assay, cellular uptake, and apoptosis assay were performed using MDA-MB-231 cell line. The gemini surfactant molecules were able to form vesicles in aqueous solution with a narrow size distribution (PDI  $\cong $  0.3). An encapsulation efficiency of 87.45 ± 2.3% and the drug loading content of 4.98 ± 0.12% were acquired. Curcumin molecules were dispersed in the hydrophobic shell of the vesicles, and sustained release profile was observed. Due to the increased cellular uptake and sustained release profile, the gemini surfactant-curcumin nanocapsules exhibited higher cytotoxicity and enhanced apoptosis in MDA-MB-231 cells compared to free curcumin. The results indicate that gemini surfactant-curcumin complex shows considerable promise as an anti-breast cancer drug.

Rakesh Agrawal

B. F. Bakare, S. Mtsweni, S. Rathilal

There is a growing pressure on the available freshwater resources in South Africa and many other countries around the world. This has led to a large scale of interest in the application of water reclamation and reuse of wastewater as alternative water supply sources. This is becoming critical to sustain development and economic growth in the southern Africa region. This study investigated the performance of a horizontal roughing filtration system treating greywater generated from a peri-urban settlement in Durban, South Africa. The horizontal roughing filtration system consists of three compartments containing different sizes of gravels that serve as the filter media. The horizontal roughing filter was operated at a filtration rate of 0.3 m/hr for 90 days. The results indicated that at this low filtration rate, effective reduction in turbidity, conductivity, chemical oxygen demand and total solids can be achieved. Overall average removal efficiencies of 90% turbidity, 70% chemical oxygen demand, 86% conductivity, and 84% total solids were obtained for the entire duration of operation of the horizontal roughing filtration system. Thus, it was concluded that the horizontal roughing filtration system is suitable for the treatment of greywater for non-potable reuse applications although further investigation needs to be conducted for the microbial removal during the treatment.

Yongjia Peng, Qiumei Shi, Yujie Wang et al.

Abstract Background The abuse of antibiotics in animal husbandry imposes a serious threat to both animal health and the environment. As a replacement for antibiotics, probiotic products have been widely used in livestock farming to promote growth of animals. However, no products specifically developed for farmed raccoon dogs and foxes are commercially available at the moment. This study was conducted to investigate the effects of mixed probiotics on farmed raccoon dogs and foxes. Results Two feeding trials on farmed raccoon dogs and foxes were performed. A mixed probiotic preparation composed of Bifidobacterium bifidum, Clostridium butyricum, Bacillus subtilis and Bacillus licheniformis was fed to these two canine species in order to assess whether such a mixed probiotics can be an alternative to antibiotics (control group). The body weight of raccoon dogs exhibited an increasing tendency with mixed probiotics administration, while that of foxes did not. The serum antioxidant activity was evaluated, and a significantly increase of total antioxidative capacity (T-AOC) was observed in both species. Illumina MiSeq was used for the sequencing of 16S rRNA genes to compare the composition of fecal microbiota between the control and mixed probiotics groups. Although α-diversity did not change, β-diversity of the fecal microbiota showed a distinct dissimilarity between the control and probiotics groups of both raccoon dogs and foxes. Dietary mixed probiotics increased the abundance of the genus Bifidobacterium in the fecal samples of raccoon dogs, and the genus Bacillus in the fecal samples of foxes. The different responses of raccoon dogs and foxes to probiotics might be the result of differences in the composition of the native gut microbiota of the two species. Conclusions The mixed probiotics preparation composed of Bifidobacterium bifidum, Clostridium butyricum, Bacillus subtilis and Bacillus licheniformis could be an effective feed additive for the improvement of the health of farmed raccoon dogs, but it may not be suitable for foxes.

Bo Wang, Yanhong Liu, Jinhui Hao et al.

Earth-abundant metal sulfides attracts large attention in recent years for hydrogen production via electrocatalytic water splitting. However, most works have been limited to the acidic condition, whereas the hydrogen evolution reaction (HER) in alkaline condition has rarely been discussed. Here we present an effective strategy for the growing of Co-Mo-S catalysts on carbon cloth via the controllable incorporation of cobalt into MoS2 with L-cysteine and phosphomolybdic acid to achieve the synergistic interaction of CoS2 and MoS2. The optimized Co-Mo-S catalysts (Co:Mo=1:2) showed a largely improved HER activity with an overpotential of 92 mV at current density of 10 mA cm-2 and Tafel slope of 82 mV dec-1. The origin of the activity enhancement was investigated through a series of characterizations, where the synergetic effect of the intrinsic fast HER kinetics of metallic CoS2 and the high active surface area of MoS2 plays a crucial role. With appropriate amount of cobalt, the Co-Mo-S catalysts show a relatively uniform distribution on the carbon cloth to ensure the large surface area, whereas excessive cobalt results in the formation of the large CoS2 particles with low HER activity from the low active surface area. Further electrochemical measurements demonstrated that the combination of larger exchange current density of CoS2 and the high electrochemical double–layer capacitance (proportional to the active surface area) of MoS2 together contributed to the HER activity enhancement of the Co-Mo-S catalysts. The Co-Mo-S/CC catalysts also show robust stability in alkaline solution. Our work provides a more profound understanding and an interesting view for the design of efficient ternary transition metal sulfide HER catalysts in alkaline condition by synergetic optimization of the intrinsic HER kinetics and the electrochemical active surface area.

N. Paidimarri, U. Virendra, S. Vedantam

Recovery of chlorine from byproduct HCl has inevitable commercial importance in industries lately because of insufficient purity or too low concentration to recycle it. Instead it is being neutralized in industries before disposing to meet stringent environmental conditions. Although recovery through catalytic oxidation processes is studied since the 19th century, their high operating conditions combined with sluggish reaction kinetics and low single pass conversions make electrolysis a better alternative. The present motive of this work is to develop a novel electrolysis process which in contrast to traditional processes effectively recovers both hydrogen and chlorine from dilute HCl. For this, an electrolytic cell with an Anionic Exchange Membrane has been designed which only allows the passage of chlorine anions from catholyte to anolyte separating the gasses in a single step. The catholyte can be as low as 3.59 wt% because of fixed anolyte concentration of 1.99 wt% which minimizes oxygen formation. Preliminary results show that the simultaneous recovery of hydrogen and chlorine is possible with high conversion up to 98%. The maximum current density value for 4.96 cm2 membrane surface area (70% active surface area) is 2.54 kAm−2, which is comparable with reported commercial processes. This study is expected to be useful for process intensification of the same in a continuous process environment.