Generating artificial homologous proteins according to the representative family character in molecular mechanics properties – an attempt in validating an underlying rule of protein evolution

AbstractThe molecular mechanics property is the foundation of many characters of proteins. Based on intramolecular hydrophobic force network, the representative family character underlying a protein’s mechanics property is described by a simple two-letter scheme. The tendency of a sequence to become a member of a protein family is scored according to this mathematical representation. Remote homologs of the WW-domain family could be easily designed using such a mechanistic signature of protein homology. Experimental validation showed that nearly all artificial homologs have the representative folding and bioactivity of their assigned family. Since the molecular mechanics property is the only consideration in this study, the results indicate its possible role in the generation of new members of a protein family during evolution

Terahertz imaging with sub-wavelength resolution by femtosecond laser filament in air

Terahertz (THz) imaging provides cutting edge technique in biology, medical sciences and non-destructive evaluation. However, due to the long wavelength of the THz wave, the obtained resolution of THz imaging is normally a few hundred microns and is much lower than that of the traditional optical imaging. We introduce a sub-wavelength resolution THz imaging technique which uses the THz radiation generated by a femtosecond laser filament in air as the probe. This method is based on the fact that the femtosecond laser filament forms a waveguide for the THz wave in air. The diameter of the THz beam, which propagates inside the filament, varies from 20 {\mu}m to 50 {\mu}m, which is significantly smaller than the wavelength of the THz wave. Using this highly spatially confined THz beam as the probe, THz imaging with resolution as high as 20 {\mu}m (~{\lambda}/38) can be realized.Comment: 10 pages, 7 figure

Terahertz Wave Guiding by Femtosecond Laser Filament in Air

Femtosecond laser filament generates strong terahertz (THz) pulse in air. In this paper, THz pulse waveform generated by femtosecond laser filament has been experimentally investigated as a function of the length of the filament. Superluminal propagation of THz pulse has been uncovered, indicating that the filament creates a THz waveguide in air. Numerical simulation has confirmed that the waveguide is formed because of the radially non-uniform refractive index distribution inside the filament. The underlying physical mechanisms and the control techniques of this type THz pulse generation method might be revisited based on our findings. It might also potentially open a new approach for long-distance propagation of THz wave in air.Comment: 5 pages, 6 figure

3-Nitro-2-phenyl­chroman

In the title compound, C15H13NO3, the dihedral angle between the two aromatic rings is 79.25 (16)°

Development of docetaxel and alendronate-loaded chitosan-conjugated polylactide-co-glycolide nanoparticles: In vitro characterization in osteosarcoma cells

Purpose: To develop docetaxel (DTX)- and alendronate (ALN)-loaded, chitosan  (CS)-conjugated polylactide- co-glycolide (PLGA) nanoparticles (NPs) to increase therapeutic efficacy in osteosarcoma cells.Methods: Drug-loaded PLGA NPs were prepared by nanoprecipitation and  chemically conjugated by the carboxylic group of PLGA to the amine-bearing CS polymer. The nanocarrier was characterized by dynamic light scattering, transmission electron microscopy, scanning electron microscopy, and differential scanning calorimetry as well as by in vitro drug release and cell culture studies.Results: NP size was within the tumour targeting range (~200 nm) with an effective positive charge (20 mV), thus increasing cellular uptake efficiency. Morphological analysis revealed clear spherical particles with uniform dispersion. The NPs  exhibited identical sustained release kinetics for both DTX and ALN. CS-conjugated PLGA with dual-drug-loaded (DTX and AL) NPs showed typical time-dependent cellular uptake and also displayed superior cytotoxicity in MG-63 cells compared with blank NPs, which were safe and biocompatible.Conclusion: Combined loading of DTX and ALN in NPs increased the therapeutic efficacy of the formulation for osteosarcoma treatment, thus indicating the potential benefit of a combinatorial drug regimen using nanocarriers for effective treatment of osteosarcoma.Keywords: Chitosan, Docetaxel, Alendronate, Nanocarriers, Sustained-release kinetics, Polylactide-coglycolide, Osteosarcoma, Cellular uptak

Application comparison of improved endotracheal tube and ordinary endotracheal tube among critically ill patients

目的  探讨改良气管导管与传统气管导管优越性比较。方法  对25例需要长期呼吸机支持治疗患者随机分为A、B两组，A组（n=12）使用改良气管导管，B组（n=13）使用传统的气管导管，两组患者分别在留管时间、ICU住院时间、憋气缓解率以及更换气管导管费用方面进行比较。结果  两组患者在GCS评分及留管时间方面无统计学意义，P>0.05，但在更换导管费用、ICU入住时间以及憋气缓解率方面，改良气管导管明显优于传统气管导管，P<0.05。结论  改良气管导管可以大大减少头端贴壁的几率，从而减少重症患者憋气发生，同时可以减少患者入住ICU的时间，大大减少住院费用。Objective: To explore the advantages of improved endotracheal tube and to compare it with traditional endotracheal tube. Methods: 25 patients requiring long-term mechanical ventilation patients were randomly divided into two groups: group A and group B. Group A (n=12) use improved endotracheal tube, and traditional endotracheal tube was used for Group B (n=13). The indwelling time, ICU hospitalization time, suffocation remission rate and replacement cost of the endotracheal tube were respectively compared between two groups. Results: GCS score and indwelling catheter time between two groups have no statistical significance, P > 0.05. Improved tracheal catheter is much better than traditional tracheal catheter with regards to catheter replacement cost, time of ICU stay and remission rate of suffocation, P<0.05. Conclusion: The improvement of the endotracheal tube can greatly reduce the rate of head end to stick wall, thus decreasing occurrence of severe shortness of breath, shortening the stay time of the patients in ICU at the same time, and greatly reducing the cost of hospitalization.