Paclitaxel (PTX) is among the most commonly used first-line drugs for cancer chemotherapy. However, its poor water solubility and indiscriminate distribution in normal tissues remain clinical ...challenges. Here we design and synthesize a highly water-soluble nucleolin aptamer-paclitaxel conjugate (NucA-PTX) that selectively delivers PTX to the tumor site. By connecting a tumor-targeting nucleolin aptamer (NucA) to the active hydroxyl group at 2' position of PTX via a cathepsin B sensitive dipeptide bond, NucA-PTX remains stable and inactive in the circulation. NucA facilitates the uptake of the conjugated PTX specifically in tumor cells. Once inside cells, the dipeptide bond linker of NucA-PTX is cleaved by cathepsin B and then the conjugated PTX is released for action. The NucA modification assists the selective accumulation of the conjugated PTX in ovarian tumor tissue rather than normal tissues, and subsequently resulting in notably improved antitumor activity and reduced toxicity.
This article proposes a collision detection algorithm without external sensors that can detect potential collisions in man–robot interaction. The algorithm is based on a modified first-order momentum ...deviation observer that also takes friction into account. The collision detection algorithm uses joint angles, angular velocities, and torques during the detection process, without any need to consider angular acceleration. The algorithm also uses an accurate friction model that is based on a Stribeck model with second-order Fourier series compensation. The friction model is applied in advance so that compensation can be made in real time during collision detection. Identification data are filtered through a first-order low-pass filter to reduce high-frequency noise. In order to verify the algorithm, a simulation and experiment were carried out using a collaborative robot experimental platform. The results confirmed that collisions can be detected by setting appropriate threshold values. Different possible responses can be implemented according to different response strategies, with the ultimate arbiter being that collision forces are kept strictly within ordinary human tolerances. This makes sure that safety can be preserved in man–robot interaction processes.
Aptamers are single-stranded DNA or RNA oligonucleotides that can interact with target molecules through specific three-dimensional structures. The excellent features, such as high specificity and ...affinity for target proteins, small size, chemical stability, low immunogenicity, facile chemical synthesis, versatility in structural design and engineering, and accessible for site-specific modifications with functional moieties, make aptamers attractive molecules in the fields of clinical diagnostics and biopharmaceutical therapeutics. However, difficulties in purification and structural identification of aptamers remain a major impediment to their broad clinical application. In this mini-review, we present the recently attractive developments regarding the purification and identification of aptamers. We also discuss the advantages, limitations, and prospects for the major methods applied in purifying and identifying aptamers, which could facilitate the application of aptamers.
Nucleation and growth lead to substantial strain in nanoparticles embedded in a host matrix. The distribution of strain field plays an important role in the physical properties of nanoparticles. ...Magnetic Ni/NiO core/shell nanoparticles embedded in the amorphous Al2O3 matrix were fabricated by pulsed laser deposition. The results from a high-resolution transmission electron microscope also revealed that the core/shell nanoparticles consist of a single crystal Ni core with a faced-centered cubic struc- ture （Space Group FM-3M） and polycrystalline Nit shell with a trigonal/rhombohedral structure （Space Group R-3mH）. The growth strain of Ni/NiO core/shell nanoparticles embedded in the Al2O3 matrix was investigated. Finite element calculations clearly indicate that the Nit shell incurs large compressive strain. The compressive strain existing at the Nit shell area ena- bles the shell material at the interface to adapt to the lattice parameters of Ni core. This process results in a relatively good crystallinity near the interface, which may be associated with the higher exchange coupling between the ferromagnetic Ni core and antiferromagnetic Nit shell.
Objective
To prepare polylactic acid microneedles (PLAMNs) with sustained antibacterial effect to avoid skin infection caused by traditional MNs-based biosensors.
Methods
Silver nanoparticles (AgNPs) ...were synthesized using an
in-situ
reduction process with polydopamine (PDA). PLAMNs were fabricated using the hot-melt method. A series of pressure tests and puncture experiments were conducted to confirm the physicochemical properties of PLAMNs. Then AgNPs were modified on the surface of PLAMNs through
in-situ
reduction of PDA, resulting in the formation of PLAMNs@PDA-AgNPs. The
in vitro
antibacterial efficacy of PLAMNs@PDA-AgNPs was evaluated using agar diffusion assays and bacterial liquid co-culture approach. Wound healing and simulated long-term application were performed to assess the
in vivo
antibacterial effectiveness of PLAMNs@PDA-AgNPs.
Results
The MNs array comprised 169 tiny needle tips in pyramidal rows. Strength and puncture tests confirmed a 100% puncture success rate for PLAMNs on isolated rat skin and tin foil. SEM analysis revealed the integrity of PLAMNs@PDA-AgNPs with the formation of new surface substances. EDS analysis indicated the presence of silver elements on the surface of PLAMNs@PDA-AgNPs, with a content of 14.44%. Transepidermal water loss (TEWL) testing demonstrated the rapid healing of micro-pores created by PLAMNs@PDA-AgNPs, indicating their safety. Both
in vitro
and
in vivo
tests confirmed antibacterial efficacy of PLAMNs@PDA-AgNPs.
Conclusions
In conclusion, the sustained antibacterial activity exhibited by PLAMNs@PDA-AgNPs offers a promising solution for addressing skin infections associated with MN applications, especially when compared to traditional MN-based biosensors. This advancement offers significant potential for the field of MN technology.
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•Immobilized microalgal dry weight rose 4.75 times at 2-day semicontinuous cultivation.•Immobilized microalgae achieved high nutrients removal rate at continuous operation.•Microalgae ...was in-situ induced inside beads to obtain valuable lipid and starch.•Immobilized microalgae performed high-speed settling and mild-temperature dewatering.
Immobilized microalgae are good for wastewater treatment and biomass production. This study investigated treatment efficiency of a continuously operated system employing immobilized microalgae for secondary effluent of wastewater treatment plants, as well as the effectiveness on induction of valuable products, harvesting and dewatering of microalgae biomass. Under semi-continuous operation condition, microalgal dry weight increased 4.75 times within 2 d, associated with the highest removal rate of ammonia and phosphate at 28.95 mg/L·d and 4.83 mg/L·d, respectively. An immobilized microalgae membrane bioreactor (iMBR) was continuously operated for a month. The harvested immobilized microalgae beads were transferred to induction stage to obtain 4.5 times increase of lipid content per cell within 2 d. Immobilized microalgae performed 1.9 cm/s settling velocity and 97% water removal efficiency around 40 °C. A prospective integrated process on resource recovery and carbon neutrality was proposed for wastewater treatment, induction, harvesting and dewatering of immobilized microalgae cells.
Purpose
This paper aims to propose a forcefree control algorithm that is based on a dynamic model with full torque compensation is proposed to improve the compliance and flexibility of the direct ...teaching of cooperative robots.
Design/methodology/approach
Dynamic parameters identification is performed first to obtain an accurate dynamic model. The identification process is divided into two steps to reduce the complexity of trajectory simplification, and each step contains two excitation trajectories for higher identification precision. A nonlinear friction model that considers the angular displacement and angular velocity of joints is proposed as a secondary compensation for identification. A torque compensation algorithm that is based on the Hogan impedance model is proposed, and the torque obtained by an impedance equation is regarded as the command torque, which can be adjusted. The compensatory torque, including gravity torque, inertia torque, friction torque and Coriolis torque, is added to the compensation to improve the effect of forcefree control.
Findings
The model improves the total accuracy of the dynamic model by approximately 20% after compensation. Compared with the traditional method, the results prove that the forcefree control algorithm can effectively reduce the drag force approximately 50% for direct teaching and realize a flexible and smooth drag.
Practical implications
The entire algorithm is verified by the laboratory-developed six degrees-of-freedom cooperative robot, and it can be applied to other robots as well.
Originality/value
A full torque compensation is performed after parameters identification, and a more accurate forcefree control is guaranteed. This allows the cooperative robot to be dragged more smoothly without external sensors.
This study aimed to evaluate the impacts of solids retention time (SRT) and influent nutrient concentration on the specific growth rate and nutrient removal efficacy of Monoraphidium sp. in a ...continuous mode membrane photobioreactor (MPBR). At SRT of 1 d, maximum biomass productivity of 421 mg·L−1·d−1 and nutrient removal rates of 59.9 % and 79.8 % for total nitrogen (TN) and total phosphorus (TP) were achieved. After reducing the influent nutrient concentration, Monoraphidium sp. maintained high biomass productivity of 385 mg·L−1·d−1 and nutrient removal rates of >95 % for TN and TP. The most important factor in Monoraphidium sp. growth assessment was intracellular nitrogen concentration (QN) rather than extracellular nutrient concentration. Flynn modified Droop model showed a better fit when the dimensionless parameter (Kq) was 0.235 for the relationship between the specific growth rate (μ) and QN. The model also revealed that even at low nitrogen concentrations (0.1 mg·L−1), the nitrogen removal capacity of Monoraphidium sp. was equal to its maximum removal capacity. Even at different extracellular nutrient concentrations, the Flynn model showed a linear relationship between μ and light irradiance per unit algae biomass (Iavp), when Iavp was below 18 μmol·g−1·s−1. This study highlights the promising potential of Monoraphidium sp. in MPBR. It demonstrates that considering QN and Iavp is essential for optimizing MPBR to achieve high biomass production and inorganic nutrient removal from secondary wastewater effluent.
•Monoraphidium sp. showed high biomass productivity and nutrient removal rates in MPBR.•Intracellular nitrogen was found to be a decisive factor for the specific growth rate of Monoraphidium sp.•Flynn's modified Droop model showed the best-fit relationship between the specific growth rate and intracellular nitrogen.•The specific growth rate was linearly increased up to an irradiance of 18 μmol·g−1·s−1 per biomass unit.
Natural dyes (ND) are gaining increasing interest due to their outstanding merits of being eco-friendly, biodegradable and non-toxic. Wood dyed with extracts from
Dalbergia cochinchinensis
residues ...as ND exhibited desirable color appearance and anti-UV property, while the other potential properties of ND dyed wood in terms of water fastness, mildew resistance along with the penetrability of the ND on wood blocks dyeing have not yet been exploited. The present study was aimed at exploring these aspects for multifunction assessment of the ND dyed wood. The results showed that the total color difference (Δ
E
*
: 4.58) and color intensity reduction (PR: 14.01%) of the ND dyed wood declined slightly after washing fastness test in comparison with that of acid red (Δ
E
*
: 32.82; RP: 76.14%) and reactive red (Δ
E
*
: 26.85; RP: 66.52%) dyed wood, which is indicative of its preferable water fastness, which can be ascribed to the hydrophobicity improvement of the wood surface after ND dyeing. In addition, the ND ameliorated the mildew resistance against
Aspergillus niger
and
Trichoderma viride
infection. Interestingly, the wood blocks can be completely impregnated with ND under atmospheric pressure dyeing process without any pretreatment and auxiliary. This study provided a promising approach for multifunctional ND dyed wood preparation.
•The optimal conditions for enrichment and purification of anthocyanins are determined.•The anthocyanins have better scavenging effects on DPPH and OH in vitro than vitamin C.•The anthocyanins are ...related to improve blood lipid metabolism of hyperlipemia rats.•The anthocyanins are related to increase the SOD activity and the TAC of hyperlipemia rats.
Anthocyanins are the main compounds in Nitraria tangutorun Bobr. The enrichment and purification of anthocyanins on macroporous resins were investigated. Regarding anthocyanin purification, static adsorption and desorption were studied. The optimal experimental conditions were the following: resin type: X-5; static adsorption time: 6h; desorption solution: ethanol–water–HCl (80:19:1, V/V/V; pH 1); desorption time: 40min. Furthermore, the in vitro and in vivo biological activities of the anthocyanins were evaluated. The anthocyanins showed ideal scavenging effects on free radicals in vitro, especially on 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl free radical (OH). In the animal experiment, blood lipid metabolism of hyperlipidemia rats was regulated by anthocyanin contents. The superoxide dismutase (SOD) activity and the total antioxidant capacity (TAC) of hyperlipidemia rats were also improved by anthocyanins. These results showed that anthocyanins from N. tangutorun Bobr. fruits had potential biological activities in vivo as well as in vitro.
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