A continuation method for image registration based on dynamic adaptive kernel.

Image registration is a fundamental problem in computer vision and robotics. Recently, learning-based image registration methods have made great progress. However, these methods are sensitive to abnormal transformation and have insufficient robustness, which leads to more mismatched points in the actual environment. In this paper, we propose a new registration framework based on ensemble learning and dynamic adaptive kernel. Specifically, we first use a dynamic adaptive kernel to extract deep features at the coarse level to guide fine-level registration. Then we added an adaptive feature pyramid network based on the integrated learning principle to realize the fine-level feature extraction. Through different scale, receptive fields, not only the local geometric information of each point is considered, but also its low texture information at the pixel level is considered. According to the actual registration environment, fine features are adaptively obtained to reduce the sensitivity of the model to abnormal transformation. We use the global receptive field provided in the transformer to obtain feature descriptors based on these two levels. In addition, we use the cosine loss directly defined on the corresponding relationship to train the network and balance the samples, to achieve feature point registration based on the corresponding relationship. Extensive experiments on object-level and scene-level datasets show that the proposed method outperforms existing state-of-the-art techniques by a large margin. More critically, it has the best generalization ability in unknown scenes with different sensor modes.

Improving Rhamnolipids Biosynthesis in Pseudomonas sp. L01 through Atmospheric and Room-Temperature Plasma (ARTP) Mutagenesis.

Biosurfactants have significant applications in various industries, including microbial-enhanced oil recovery (MEOR). While the state-of-the-art genetic approaches can generate high-yield strains for biosurfactant production in fermenters, there remains a critical challenge in enhancing biosurfactant-producing strains for use in natural environments with minimal ecological risks. The objectives of this work are enhancing the strain's capacity for rhamnolipids production and exploring the genetic mechanisms for its improvement. In this study, we employed atmospheric and room-temperature plasma (ARTP) mutagenesis to enhance the biosynthesis of rhamnolipids in Pseudomonas sp. L01, a biosurfactant-producing strain isolated from petroleum-contaminated soil. Following ARTP treatment, we identified 13 high-yield mutants, with the highest yield of 3.45 ± 0.09 g/L, representing a 2.7-fold increase compared to the parent strain. To determine the genetic mechanisms behind the enhanced rhamnolipids biosynthesis, we sequenced the genomes of the strain L01 and five high-yield mutants. A comparative genomic analysis suggested that mutations in genes related to the synthesis of lipopolysaccharides (LPS) and the transport of rhamnolipids may contribute to the improved biosynthesis. To the best of our knowledge, this is the first instance of utilizing the ARTP approach to improve rhamnolipid production in Pseudomonas strains. Our study provides valuable insights into the enhancement of biosurfactant-producing strains and the regulatory mechanisms of rhamnolipids biosynthesis.

Degradation of crude oil in a co-culture system of Bacillus subtilis and Pseudomonas aeruginosa.

Microbial remediation has been regarded as one of the most promising decontamination techniques for crude oil pollution. However, there are few studies on the interaction of bacteria in the microbial community during bioremediation. The aim of this work was to research the promotion of defined co-culture of Bacillus subtilis SL and Pseudomonas aeruginosa WJ-1 for biodegradation of crude oil. After 7 days of incubation, the analysis of residual oil, saturated and aromatic fraction in the samples showed that the degradation efficiency of them was significantly improved. The degradation efficiency of crude oil was enhanced from 32.61% and 54.35% in individual culture to 63.05% by the defined co-culture of strains SL and WJ-1. Furthermore, it was found that the defined co-culture system represented relatively excellent performance in bacterial growth, cell surface hydrophobicity (CSH) and emulsification activity. These results indicated that the combination of Bacillus subtilis and Pseudomonas aeruginosa can effectively promote the degradation and utilization of crude oil, which may provide a new idea for the improvement of bioremediation strategies. GRAPHICAL ABSTRACT.

Research advances of microbial enhanced oil recovery.

Microbial enhanced oil recovery (MEOR), characterized with the virtues of low cost and environmental protection, reflects the prevalent belief in environmental protection, and is attracting the attention of more researchers. Nonetheless, with the prolonged slump in global oil prices, how to further reduce the cost of MEOR has become a key factor in its development. This paper described the recent development of MEOR technology in terms of mechanisms, mathematical models, and field application, meanwhile the novel technologies of MEOR such as genetically engineered microbial enhanced oil recovery (GEMEOR) and enzyme enhanced oil recovery (EEOR) were introduced. The paper proposed three possible methods to decrease the cost of MEOR: using inexpensive nutrients as substrates, applying a mixture of chemical and biological agents, and utilizing crude microbial products. Additionally, in order to reduce the uncertainty in the practical application of MEOR technology, it is essential to refine the reservoir screening criteria and establish a sound mathematical model of MEOR. Eventually, the paper proposes to combine genetic engineering technology and microbial hybrid culture technology to build a microbial consortium with excellent oil displacement efficiency and better environmental adaptability. This may be a vital part of the future research on MEOR technology, which will play a major role in improving its economic efficiency and practicality.

Biosurfactant production by Bacillus subtilis SL and its potential for enhanced oil recovery in low permeability reservoirs.

Microbial enhanced oil recovery (MEOR) technology is an environmental-friendly EOR method that utilizes the microorganisms and their metabolites to recover the crude oil from reservoirs. This study aims to research the potential application of strain SL in low permeability reservoirs. Strain SL is identified as Bacillus subtilis by molecular methods. Based on the mass spectrometry, the biosurfactant produced by strain SL is characterized as lipopeptide, and the molecular weight of surfactin is 1044, 1058, 1072, 1084 Da. Strain SL produces 1320 mg/L of biosurfactant with sucrose as the sole carbon source after 72 h. With the production of biosurfactant, the surface tension of cell-free broth considerably decreases to 25.65 ± 0.64 mN/m and the interfacial tension against crude oil reaches 0.95 ± 0.22 mN/m. The biosurfactant exhibits excellent emulsification with crude oil, kerosene, octane and hexadecane. In addition, the biosurfactant possesses splendid surface activity at pH 5.0-12.0 and NaCl concentration of 10.0% (w/v), even at high temperature of 120 °C. The fermentation solution of strain SL is applied in core flooding experiments under reservoir conditions and obtains additional 5.66% of crude oil. Hence, the presented strain has tremendous potential for enhancing the oil recovery from low-permeability reservoirs.

Study on the treatment of oily sludge in oil fields with lipopeptide/sophorolipid complex bio-surfactant.

A systematic study had been carried out to get insight into the micellar behavior of anionic lipopeptide (LT) and nonionic sophorolipid (SL) in their different mass ratio mixed state using the technique of tensiometry. The models proposed by Clint, Rubingh and Gibbs et al. had been employed to interpret the formation of mixed micelles and found out synergism. The obtained experimental critical micelle concentrations (CMC) were lower than the ideal CMCs, indicating negative deviation from ideal behavior for all multi-component mixed micelles formation. A suited binary bio-surfactant mixing system was selected as the washing agents to treat the oily sludge produced from Huabei oilfield by the thermal bio-surfactant washing method. The results showed that in case of the mass ratios of 8:2 the CMC was dramatically decreased and synergism was the strongest in LT and SL bi mixed surfactant systems. The studied binary mixed bio-surfactant system showed higher washing efficiency for oily sludge than single surfactant system. In addition, the washing power of binary mixed bio-surfactants towards oily sludge was the best at below washing conditions: (a) the concentration of the mixed system (100 mg/L), (b) temperature (55 â„ƒ), (c) ratio of sludge/liquid (1:3), (d) washing time (3 h), and (e) stirring speed (300 rpm). Certainly, the washing abilities of the selected surfactants not only depend on their mixing ratio and washing conditions but also associate with microstructure and mineral components of oily sludge.

Novel docetaxel-loaded nanoparticles based on PCL-Tween 80 copolymer for cancer treatment.

BACKGROUND: The formulation of docetaxel available for clinical use (Taxotere) contains a high concentration of polysorbate 80 (Tween 80). After incorporation of Tween 80 into poly-ɛ-caprolactone (PCL)-Tween 80 copolymer, the relative amount of Tween 80 should be decreased and the advantages of PCL and Tween 80 should be combined. METHODS: A novel PCL-Tween 80 copolymer was synthesized from ɛ-caprolactone and Tween 80 in the presence of stannous octoate as a catalyst via ring opening polymerization. Two types of nanoparticle formulation were made from commercial PCL and a self-synthesized PCL-Tween 80 copolymer using a modified solvent extraction/evaporation method. RESULTS: The nanoparticles were found by field emission scanning electron microscopy to have a spherical shape and be 200 nm in diameter. The copolymers could encapsulate 10% of the drug in the nanoparticles and release 34.9% of the encapsulated drug over 28 days. PCL-Tween 80 nanoparticles could be internalized into the cells and had higher cellular uptake than the PCL nanoparticles. The drug-loaded PCL-Tween 80 nanoparticles showed better in vitro cytotoxicity towards C6 cancer cells than commercial Taxotere at the same drug concentration. CONCLUSION: Nanoparticles using PCL-Tween 80 copolymer as drug delivery vehicles may have a promising outcome for cancer patients.

Nanoparticles of Poly(Lactide-Co-Glycolide)-d-a-Tocopheryl Polyethylene Glycol 1000 Succinate Random Copolymer for Cancer Treatment.

Cancer is the leading cause of death worldwide. Nanomaterials and nanotechnologies could provide potential solutions. In this research, a novel biodegradable poly(lactide-co-glycolide)-d-a-tocopheryl polyethylene glycol 1000 succinate (PLGA-TPGS) random copolymer was synthesized from lactide, glycolide and d-a-tocopheryl polyethylene glycol 1000 succinate (TPGS) by ring-opening polymerization using stannous octoate as catalyst. The obtained random copolymers were characterized by 1H NMR, FTIR, GPC and TGA. The docetaxel-loaded nanoparticles made of PLGA-TPGS copolymer were prepared by a modified solvent extraction/evaporation method. The nanoparticles were then characterized by various state-of-the-art techniques. The results revealed that the size of PLGA-TPGS nanoparticles was around 250 nm. The docetaxel-loaded PLGA-TPGS nanoparticles could achieve much faster drug release in comparison with PLGA nanoparticles. In vitro cellular uptakes of such nanoparticles were investigated by CLSM, demonstrating the fluorescence PLGA-TPGS nanoparticles could be internalized by human cervix carcinoma cells (HeLa). The results also indicated that PLGA-TPGS-based nanoparticles were biocompatible, and the docetaxel-loaded PLGA-TPGS nanoparticles had significant cytotoxicity against Hela cells. The cytotoxicity against HeLa cells for PLGA-TPGS nanoparticles was in time- and concentration-dependent manner. In conclusion, PLGA-TPGS random copolymer could be acted as a novel and promising biocompatible polymeric matrix material applicable to nanoparticle-based drug delivery system for cancer chemotherapy.

Enhancement of immunotherapeutic effects of HPV16E7 on cervical cancer by fusion with CTLA4 extracellular region.

Cervical cancer is caused by infection by high-risk human papillomavirus (HPV), especially HPV16. Limitations in current treatments of cervical cancers call for the development of new and improved immunotherapies. This study aims at investigating the efficacy of a novel vaccine consisting of modified HPV 16E7 fused with human cytotoxic T-lymphocyte antigen 4 (CTLA4). The regions in HPV16 E7 gene associated with its transformation and CTL-enhanced response were modified; the resultant HPV16mE7 was fused with extracellular region of CTLA4 to generate HPVml6E7-eCTLA4 fusion protein. Binding of this fusion protein to B7 molecules expressed on antigen presenting-cells (APCs) was demonstrated. C57BL/6 (H-2b) mice immunized with low dose of the fusion protein (10 microg) produced higher titer antibody and stronger specific CTL response, and expressed higher levels of IFN-gamma and IL-12, compared with those immunized with HPVml6E7 only or admixture of HPVml6E7 and CTLA4, or PBS; and were protected from lethal dose tumor challenge. Tumor growth was retarded and survival prolonged in mouse models with the fusion protein treatment. Our results demonstrate that fusion of HPV16 E7 with eCTLA4 targeting APCs resulted in enhanced immunity, and that this fusion protein may be useful for improving the efficacy of immunotherapeutic treatments of cervical cancer and other HPV16 infection-associated tumors.