A Novel Model for Evaluating the Natural Antioxidant Carnosic Acid to Improve the Stability of Rapeseed Oil in the Thermal Degradation.

The quality and stability of oil during thermal processing reflect the reactions in vegetable oil. The deterioration of the oil is close to the viscosity, fatty acid composition (FA), total polar compounds (TPC), etc. Carnosic acid (CA) is the main antioxidant component of rosemary extract; it is a natural and clean-label antioxidant that is allowed to be added to prolong oil processing and storage. To achieve a clear correlation of this situation, a novel stability evaluation model was used to predict the thermal degradation of rapeseed oil (RSO) with CA. The RSO with CA (200 mg/kg, 400 mg/kg, and 700 mg/kg), the tert-Butylhydroquinone (TBHQ, 200 mg/kg), and the fresh RSO (without additives) during thermal processing (180 ± 5 °C) were studied. The temperature dependency of viscosity fits well with the Lioumbas model (R2 ≥ 0.999). The parameter b value in the Lioumbas model showed a decrease linearly with the processing time (tP, R2 ≥ 0.965). The multiple linear regression analysis showed that the accuracy of the model in predicting viscosity was less than ±2 mPa·s-1, and the deviation% was less than ±10% in all the samples. After 32 h of thermal degradation, the addition of 700 mg/kg CA showed the lowest degradation rate (13.84%) of polyunsaturated fatty acids (PUFAs), and the TPC content was 26.00 ± 0.50%. The TPC showed a positive relationship with viscosity (r = 0.99, p < 0.01), tP (r = 0.97, p < 0.01), and effective carbon numbers (ECN, r = 0.84, p < 0.05). In conclusion, this study can make a potential prediction for the stability of RSO.

Atomistically informed hierarchical modeling for revisiting the constituent structures from heredity and nano-micro mechanics of sheath-core carbon fiber.

To better understand the heterogeneous anisotropic nanocomposite features and provide reliable underlying constitutive parameters of carbon fiber for continuum-level simulations, hierarchical modeling approaches combining quantum chemistry, molecular dynamics, numerical and analytical micromechanics are employed for studying the structure-performance relationships of the precursor-inherited sheath-core carbon fiber layers. A robust debonding force field is derived from energy matching protocols, including bond dissociation enthalpy calculations and rigid-constraint potential energy surface scan. Logistic long range bond stretching curves with exponential parameters and shifted force vdW curves are designed to diminish energy perturbations. The pseudo-crystalline microstructure is proposed and validated using virtual wide angle X-ray diffraction patterns and bond-orientational order parameters. The distribution or alignment features of the nanocomposite microstructures are collected from quantum chemical topology analysis and normal vector extractions. Non-equilibrium tensile loading simulation predicts the decomposed strain energy contributions, principal-axis modulus, strength limit, localized stress, and fracture morphologies of the model. Finally, an atomistically-informed stiffness prediction model combining numerical homogenization and analytical self-consistent Eshelby-Mori-Tanaka-type effective mean field micromechanics theory is proposed, giving a successful estimation of the overall stiffness matrix of the sheath-core carbon fiber system. The hierarchical models in combination with the carbonization reaction template will help in providing efficient and feasible schemes for the synergistic process-performance control of distinct types of carbon fiber.

Atomistic Modeling of the Effect of Temperature on Interfacial Properties of 3D-Printed Continuous Carbon Fiber-Reinforced Polyamide 6 Composite: From Processing to Loading.

The combination of continuous fiber-reinforced thermoplastic composites (CFRTPCs) and the continuous fiber 3D printing (CF3DP) technique enables the rapid production of complex structural composites. In these 3D-printed composites, stress transfer primarily relies on the fiber-resin interface, making it a critical performance factor. The interfacial properties are significantly influenced by the temperatures applied during the loading and forming processes. While the effect of the loading temperature has been extensively researched, that of the forming temperature remains largely unexplored, especially from an atomistic perspective. Our research aims to employ molecular dynamics simulations to elucidate the effect of temperature on the interfacial properties of continuous carbon fiber-reinforced polyamide 6 (C/PA6) composites fabricated using the CF3DP technique, considering both loading and forming aspects. Through molecular dynamics simulations, we uncovered a positive correlation between the interfacial strength and forming temperature. Moreover, an increased forming temperature induced a notable shift in the failure mode of C/PA6 under uniaxial tensile loading. Furthermore, it was observed that increasing loading temperatures led to the deterioration of the mechanical properties of PA6, resulting in a gradual transition of the primary failure mode from adhesive failure to cohesive failure. This shift in the failure mode is closely associated with the glass transition of PA6.

Current Technologies and Uses for Fruit and Vegetable Wastes in a Sustainable System: A Review.

The fruit and vegetable industry produces millions of tons of residues, which can cause large economic losses. Fruit and vegetable wastes and by-products contain a large number of bioactive substances with functional ingredients that have antioxidant, antibacterial, and other properties. Current technologies can utilize fruit and vegetable waste and by-products as ingredients, food bioactive compounds, and biofuels. Traditional and commercial utilization in the food industry includes such technologies as microwave-assisted extraction (MAE), supercritical fluid extraction (SFE), ultrasonic-assisted extraction (UAE), and high hydrostatic pressure technique (HHP). Biorefinery methods for converting fruit and vegetable wastes into biofuels, such as anaerobic digestion (AD), fermentation, incineration, pyrolysis and gasification, and hydrothermal carbonization, are described. This study provides strategies for the processing of fruit and vegetable wastes using eco-friendly technologies and lays a foundation for the utilization of fruit and vegetable loss/waste and by-products in a sustainable system.

Insights into the carbonization mechanism of PAN-derived carbon precursor fibers and establishment of a kinetics-driven accelerated reaction template for atomistic simulation.

To better understand the chemistry behind the carbonization process of the polyacrylonitrile (PAN)-based precursor fibers and provide a more authentic virtual counterpart of the process-inherited model for process optimization and rational performance design, we develop arrow-pushing reaction routes for primary exhaust gas product (H2O/H2/HCN/N2/tar vapor) formation and a pragmatic kinetics-driven accelerated reaction template for atomistic simulation of the carbonization process overcoming traditional challenges in time scale discrepancy of the reaction-diffusion system. The results of enthalpy barriers from hybrid first principles calculations validate the rationality and sequence of conjectured reactions during the two-stage carbonization process. Conversion rates of the rate-determining steps under 300 s carbonization are also estimated based on Eyring's transition state theory realizing kinetics equivalency of the reaction extent. Process-control measurements are further demonstrated corresponding to the proposed mechanism. The iterative densified crosslinking scheme specially designed for the surface layer is implanted into the topological reaction molecular dynamics template and a series of highly devisable structural models during the whole evolutionary process from the pre-oxidized fiber to the pristine carbon fiber surface are successfully predicted. The ultimate structure of the model presents excellent similarity in carbon yield and elemental composition with the type II high strength carbon fiber surface.

High-frequency vibration effects on material removal mechanisms in ultrasonic transverse scratching of carbon fiber reinforced plastics.

This paper represented some fundamental investigations on the potential effects of the high-frequency vibration on material removal mechanisms in ultrasonic transverse scratching of carbon fiber reinforced plastics (CFRPs). It was found that the ultrasonic superimposition brought about the evident reduction of the ductile-brittle transition depth of the unidirectional CFRPs. For the scratched groove generated without ultrasonic, the tensile stress and compressive stress caused by the indenter penetration were respectively responsible for the formations of the radial cracks at the leading edges and the central region. Under the combination of the inertia effects induced by the ultrasonic superposition and the skin-core structure of the carbon fibers, the micro-defects situated at the interior of the fibers were nucleated simultaneously, and their propagations caused the formations of the oblique cracks. Incorporated with the strain rate effects of the materials, a fresh theoretical model was proposed to describe the evolution of the mechanical stress during the scratching process. The fiber fragments induced by the oblique cracks were just concentrated on the top surface of the scratched groove, due to the coupling effects of the small penetration depth of the indenter and the express reduction of strain rate.

High-frequency vibration effects on the hole integrity in rotary ultrasonic drilling of carbon fiber-reinforced plastic composites.

This investigation represented a fundamental research on the potential effects of the high-frequency vibration on the hole integrity involved in rotary ultrasonic drilling (RUD) of carbon fiber-reinforced plastic (CFRP) composites. It was found the increased thickness of the CFRP plate shrunk the flowing velocity of the coolant, which brought about the residual chippings gradually accumulated at the radial clearance between the tool and the material. Furthermore, the chipping accumulation at the clearance seriously increased the friction effects and the resultant thermal load, thus leading to the chipping adhesions on the tool surface and machined cylinder jamming at the central hole of the tool. The mutual constrain between two vertical bundles brought the delamination around the holes generated in conventional drilling (CD) process to a termination at the bundle interface. The ultrasonic superimposition reduced the thrust force of the diamond tool which provided inadequate energy for the delaminated fibers reaching the bundle interface. Moreover, hole position on the two-dimensional orthogonal fabrics significantly influenced the propagation of the delaminated fibers, which weakened the effects of the drilling parameters on the delamination dimensions. Additionally, superimposing an ultrasonic vibration prolonged the abrasive trajectories and increased their overlapping probability, and the induced smoothing effects resulted in the obvious reduction of the surface roughness. The tensile stress exerted on the margin of the machined surface was responsible for the initiation of the CD delamination. After the delaminated fibers reached the bundle interface, the further extrusion of tool brought about the margin suffered from the shear stress, thus leading to the collapse of the machined cylinder. Considering the thrust force of the diamond tool and the undrilled thickness of the machined surface, the critical conditions of the delamination initiation were developed, which revealing that the decreasing of the thrust force caused the reduction of the critical undrilled thickness.

Simulation of Wrinkling during Bending of Composite Reinforcement Laminates.

When a thick laminate is subjected to bending, under certain boundary conditions, wrinkles may appear and develop due to the inextensibility of the fibers. Wrinkling is one of the most critical defects in composite manufacturing. Numerical simulation of the onset and growth of such wrinkles is an important tool for defining optimal process parameters. Herein, several bending experiments of thick laminates are presented. They were found to lead to severe wrinkling and delamination of different kinds. It is shown that the history of loading changed the developed wrinkles. Stress resultant shell finite elements specific to textile reinforcement forming show their relevance to provide, for these wrinkles induced by bending, results in good agreement with the experiments, both with regard to the onset of the wrinkles and to their development. This numerical approach was used to improve the understanding of the phenomena involved in wrinkling and to define the conditions required to avoid it in a given process.

Direct combustion of waste oil in domestic stove by an internal heat re-circulation atomization technology: Emission and performance analysis.

Direct use of waste oil as fuel to meet the residential energy demands, is very attractive due to its potentials to decrease fossil fuel consumption, reduce pollution and increase sustainability. This paper uses a domestic stove with an internal heat re-circulation and self-atomization technology to burn yellow waste cooking oil (WCO-1), brown waste cooking oil (WCO-2) and waste lubricant oil (WLO). Emission factors (EFs), energy efficiency and modified combustion efficiency (MCE) of this combined fuel/stove system were determined under space-heating and cooking modes. The results showed that EFs of CO, PM2.5, total 16 PAHs and corresponding toxic equivalent quantity (TEQ) values ranged from 2.18 × 103 to 4.90 × 103 mg/MJnet, 16.36-69.40 mg/MJnet, 2.39-12.93 µg/MJnet and 0.16-0.92 µg of TEQ/MJnet. WCO-1 was verified to be the cleanest fuel with the highest energy efficiency (85.3 ± 3.3% and 90.4 ± 2.2%) and lowest emission levels, such as NO (53.75 ± 2.62 and 37.09 ± 5.41 mg/MJnet), NO2 (82.40 ± 3.96 and 56.87 ± 8.29 mg/MJnet) and PM2.5 (20.94 ± 6.55 and 16.35 ± 5.06 mg/MJnet) compared to WCO-2 and WLO. The estimated total cost of using waste oil for each household in winter was much cheaper than some current available clean energy means, including only USD$ 400 of stove price and USD$ 250/ton of fuel per year. It is a promising candidate choice for replacing low-quality solid fuels in rural China and 2.62 million rural households would achieve environmental and economic benefits if promoting direct combustion of waste oil for daily heating and cooking.

Mechanistic prediction for cutting force in rotary ultrasonic machining of BK7 glass based on probability statistics.

Material removal in rotary ultrasonic machining (RUM) of hard-brittle material is an abnormal complicated process, which involves the combination effects of the numerous abrasive grains with the random distributions in the dimensions and penetration depths. These stochastic characteristics result in the evident differences in the extrusion loading between the material and each individual grain, and their aggregate effects serve to significantly affect the cutting force of the diamond tool. However, few mechanistic prediction models of the cutting force have incorporated in the random distribution features of the abrasive grains, restricting the current optimization methods for the reduction of the cutting force during the formal RUM process. Giving consideration to the abrasive processing kinematics and their distribution features on the tool end-face, the number of the effective grains together with their penetration depths was calculated utilizing the probability statistics. Subsequently, the novel theoretical model of the cutting force was established by incorporating the gaussian distribution characteristics of the grain size and their penetration depths. Afterward, the confirmatory experiments were performed for the validation of the proposed cutting force model, revealing that the predicted results were accordant well with the experimental measurements. Furthermore, it was found that the number of the active abrasive grains accounted for 2.972% of the total number on the tool end-face at the specific processing parameters. Additionally, the mechanistic predictions of the developed model represented that the cutting force depicting an irregular decreasing trend with the grain dimension increasing, which was attributed to the coupling effects between the grain size and their number.

Interfacial microstructure and properties of carbon fiber composites modified with graphene oxide.

The performance of carbon fiber-reinforced composites is dependent to a great extent on the properties of fiber-matrix interface. To improve the interfacial properties in carbon fiber/epoxy composites, we directly introduced graphene oxide (GO) sheets dispersed in the fiber sizing onto the surface of individual carbon fibers. The applied graphite oxide, which could be exfoliated to single-layer GO sheets, was verified by atomic force microscope (AFM). The surface topography of modified carbon fibers and the distribution of GO sheets in the interfacial region of carbon fibers were detected by scanning electron microscopy (SEM). The interfacial properties between carbon fiber and matrix were investigated by microbond test and three-point short beam shear test. The tensile properties of unidirectional (UD) composites were investigated in accordance with ASTM standards. The results of the tests reveal an improved interfacial and tensile properties in GO-modified carbon fiber composites. Furthermore, significant enhancement of interfacial shear strength (IFSS), interlaminar shear strength (ILSS), and tensile properties was achieved in the composites when only 5 wt % of GO sheets introduced in the fiber sizing. This means that an alternative method for improving the interfacial and tensile properties of carbon fiber composites by controlling the fiber-matrix interface was developed. Such multiscale reinforced composites show great potential with their improved mechanical performance to be likely applied in the aerospace and automotive industries.

Honeycomb-structured films by multifunctional amphiphilic biodegradable copolymers: surface morphology control and biomedical application as scaffolds for cell growth.

Recently, fabrication of functional porous polymer films with patterned surface structures at the scale from nanometer to micrometer has been attracting increasing interests in material science and nanobiotechnology. In this work, we present new preparation of two series of multifunctional amphiphilic copolymers and preparation of their microporous thin films on solid substrates. First, diblock dendritic poly(l-lysine)-b-poly(l-lactide)s and triblock dendritic poly(l-lysine)-b-poly(l-lactide)-b-dendritic poly(l-lysine)s (C1-C6) were synthesized through 4-dimethylaminopyridine (DMAP)-catalyzed living ring-opening polymerization of (l-)-lactide with (l-)-lysine dendron initiators, and their structures were characterized by nuclear magnetic resonance spectrometer (NMR), gel permeation chromatography (GPC) and matrix-assisted laser desorption/ionization Fourier-transformed mass spectra (MALDI-FTMS). Employing the breath-figure (BF) fabrication strategy, thin films of the synthesized amphiphiles (C1-C6) were drop-cast, and their surface topologies were examined by scanning electron microscopy (SEM) and atomic force microscopy (AFM), and the effects of new amphiphile structure and drop-casting parameters of amphiphile concentration, humidity and temperature on self-assembly of ordered porous surface were studied. Furthermore, the influence of surface energy of drop-casting substrates was additionally investigated. With a human cervical epithelial carcinoma cell line (HeLa), cytotoxicity of the prepared honeycomb-structured films by new amphiphile C6 was evaluated by thiazoyl-blue-tetrazolium-bromide (MTT) assay, and HeLa cell growth behavior with microporous amphiphile films as the scaffolds was also examined. It was found that tunable micropore diameter sizes and well ordered surface topologies of BF films could be achieved for the new prepared amphiphiles, and utilization of the honeycomb-like microporous films as scaffolds indicated favorable enhancement in cell proliferation. Therefore, the honeycomb-structured films by these biocompatible multifunctional amphiphiles may provide new materials as 3D-scaffold materials for potential application in tissue engineering and regeneration.

The intracellular plasmid DNA localization of cationic reducible cholesterol-disulfide lipids.

Stimuli-responsive biomaterials derived from natural products toward efficient drug/gene delivery have been attracting increasing attention in the past decade. In this work, we first designed and prepared a new series of cholesterol-disulfide lipids, namely CHOSS-N, CHOSS-N+, CHOSS-Lys and CHOSS-4N bearing cholesterol and a variety of headgroups via disulfide and carbonate bond linkages, and their molecular structures were characterized by NMR and ESI-MS. Furthermore, plasmid DNA binding affinity for these new CHOSS lipids was separately examined by ethidium bromide displacement and agarose-gel retardant assay. Average diameter sizes and surface potentials of the CHOSS/pDNA lipoplex particles prepared under various N/P charge ratios were analyzed by dynamic laser light scattering (DLS). Under 10 mm dithiothreitol (DTT), stability and disassembly of the CHOSS/pDNA lipoplex nanoparticles were investigated by agarose-gel retardant assay and atomic force microscopy (AFM). Employing a COS-7 cell line, cell viability was examined for the prepared CHOSS lipids and their pDNA lipoplexes with branched PEI-25k as the reference. Finally, COS-7 cell gene transfection efficacies with these CHOSS lipids as potential delivery vectors were investigated by luciferase and EGFP transfection assay in the absence and presence of serum, and intracellular uptake capability, trafficking and cellular localization of Cy3-labeled pEGFP-N1 DNA were studied with a flow cytometer and fluorescent microscopy with Lipofectamine™ 2000 as the control. The results demonstrated low cytotoxicity, strong pDNA binding affinity and high transgenetic efficacy for new prepared CHOSS lipids, and particularly high intracellular uptake capability and specific cellular localization of pDNA at the periphery of cell nuclei were for the first time interestingly observed for the CHOSS lipid delivery carriers. In general, these may pave a new way to utilize cholesterol, amino acids and other functional natural products to prepare efficient gene/drug delivery carriers with simple structure and low cytotoxicity.

Amphiphilic cationic [dendritic poly(L-lysine)]-block-poly(L-lactide)-block-[dendritic poly(L-lysine)]s in aqueous solution: self-aggregation and interaction with DNA as gene delivery carriers.

A new series of triblock [dendritic poly(L-lysine)]-block-PLLA-block-[dendritic poly(L-lysine)]s (DL(2) -PLLA-DL(2) ) with PLLA block lengths of 11.5-26.5 and double 2-generation PLL dendrons DL(2) as model cationic amphiphiles were synthesized and characterized. Their CAC, self-aggregation and plasmid DNA binding affinities in pure water and PBS were studied. The PLLA block length dependence of particle size, morphology and ξ potential for organized pDNA/amphiphile polyplex aggregates were examined. Finally, toxicities of these DL(2) -PLLA-DL(2) amphiphiles and their polyplexes were assayed by MTT with HeLa, SMMC-7721 and COS-7 cells, and COS-7 cell luciferase and eGFP gene transfection efficacies with these amphiphiles as the delivery carriers were investigated.

Interactions of new synthesized fluorescent cationic amphiphiles bearing pyrene hydrophobe with plasmid DNA: binding affinities, aggregation and intracellular uptake.

In this work, we prepared a novel series of cationic amphiphiles denoted as the Py-cations (Py-Gly, Py-Ala, Py-Cap, Py-G(1)-Lys and Py-G(2)-Lys) bearing fluorescent pyrene and various hydrocarbon linkers between the pyrene hydrophobe and cationic block. Employing these new cationic amphiphiles with pyrene as the fluorescent probe, the interactions between these Py-cations and plasmid DNA (pDNA) in distilled water and 0.1 M PBS buffer solution have been explored by means of UV-vis and fluorescent spectrometers, and ethidium bromide dye displacement and agarose-gel retardant assays were also implemented to evaluate their pDNA binding affinities in aqueous solution. Furthermore, the average sizes and morphologies of self-assembled Py-cation/pDNA lipoplex aggregates were examined by dynamic laser light scattering (DLS) and atomic force microscopy (AFM). It was found that these fluorescent cationic amphiphiles showed blue fluorescence emission of pyrene probe at λ = 340 nm in distilled water while their interactions with pDNA led to new strong green emission at λ = 490 nm, and this may be due to the stacking of pyrene and new formation of excimers via the rigid pDNA templated self-assembly. It was also revealed that the binding between new Py-cations and pDNA in aqueous solution was strongly influenced by the Py-cation hydrophobicity, charges of the cation and the presence of electrolytes. With respect to the Py-cation/pDNA aggregate morphologies, very interesting 1-D hybrid nanofibers were predominantly observed by AFM for the Py-Cap/pDNA aggregates. In addition, utilizing a COS-7 cell-line, in-vitro cellular uptakes of new cationic amphiphiles with pyrene probe were studied and visualized by fluorescent microscopy. As a result, this may provide a new approach to investigate the interactions between synthetic cationic lipids and nucleic acids, and pave an alternative clue to design new organic gene delivery carriers.

Dendritic poly(L-lysine)-b-Poly(L-lactide)-b-dendritic poly(L-lysine) amphiphilic gene delivery vectors: roles of PLL dendritic generation and enhanced transgene efficacies via termini modification.

As an effort to prepare new efficient gene delivery vectors, we have recently developed and reported an amphiphilic dendritic poly(L-lysine)-b-poly(L-lactide)-b-dendritic poly(L-lysine) D(2)-PLLA-D(2) with two-generation PLL dendrons and a PLLA block. In this work, we continued to explore the roles of dendritic PLL generation in DNA binding and intracellular delivery of gene, and a new series of amphiphilic dendritic poly(L-lysine)-b-poly(L-lactide)-b-dendritic poly(L-lysine)s D(n)-PLLA-D(n) (n = 3-5) were synthesized and were structurally characterized. Furthermore, plasmid DNA binding affinity for these cationic amphiphiles was examined by agarose gel electrophoresis and fluorescence titration assay in pure water and PBS buffer solution containing 150 mM NaCl (pH = 7.4), respectively. By dynamic light scattering (DLS) and transmission electronic microscopy (TEM), the interaction and complexation in between were investigated, concerning the DNA/vector polyplex particle morphologies and zeta potentials. Utilizing a human hepatocellular carcinoma cell-line SMMC-7721, cell toxicity, and gene transfection in vitro were explored. To further improve transgene efficiency for these synthetic cationic amphiphiles as gene delivery vectors, new structural DE(n)-PLLA-DE(n) (n = 2-3) were prepared through an amino termini modification of the D(n)-PLLA-D(n) (n = 2-3) with less toxic 4,7,10,13-tetraazatridecanoic acids, and gene transfection with these DE(n)-PLLA-DE(n) (n = 2-3) was examined with an alternative human gastric carcinoma cell-line HGC-27. As a result, the high plasmid DNA binding affinity, low cytotoxicity, and much enhanced transgene efficacy suggest a new possible clue to design effective synthetic gene delivery vectors with amphiphilic skeleton and less toxic polyamine building blocks.

New preparation of structurally symmetric, biodegradable poly(L-lactide) disulfides and PLLA-stabilized, photoluminescent CdSe quantum dots.

New, biodegradable poly(L-lactide) disulfides, PLLA-SS-PLLA, were first prepared through the DMAP-catalyzed ring-opening polymerization of L-lactide with a dihydroxyethyl disulfide initiator, and were further catalytically reduced into thiol-end-functionalized poly(L-lactide)s, HO-PLLA-SH, with a tributyl phosphine catalyst (PBu3). Employing the HO-PLLA-SH as the ligand, new core-shell CdSe/PLLA quantum dots (QDs) were continuously prepared via a facile ligand-exchanging process with the CdSe/TOPO QD precursor. The chemical structures, morphologies and solvent solubility of these prepared CdSe/PLLA QDs were investigated by NMR spectroscopy, FTIR spectroscopy, XRD, TEM and excitation under either room light or UV radiation at 365 nm, demonstrating the successful ligand replacement and the new formation of core-shell CdSe/PLLA QDs (diameter:4.0 +/- 0.3 nm). Finally, UV and FL results indicate the two factors of the HO-PLLA-SH ligand molecular weight and the ligand/QD precursor feeding weight ratio were important for preparing stable and highly photoluminescent CdSe/PLLA QDs.