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71.
Jun Zhang Da‐Wei Wang Wei Lv Lei Qin Shuzhang Niu Siwei Zhang Tengfei Cao Feiyu Kang Quan‐Hong Yang 《Liver Transplantation》2018,8(26)
Sodium‐ion batteries (SIBs) have the potential to be practically applied in large‐scale energy storage markets. The rapid progress of SIBs research is primarily focused on electrodes, while electrolytes attract less attention. Indeed, the improvement of electrode performance is arguably correlated with the electrolyte optimization. In conventional lithium‐ion batteries (LIBs), ether‐based electrolytes are historically less practical owing to the insufficient passivation of both anodes and cathodes. As an important class of aprotic electrolytes, ethers have revived with the emerging lithium‐sulfur and lithium‐oxygen batteries in recent years, and are even booming in the wave of SIBs. Ether‐based electrolytes are unique to enabling these new battery chemistries in terms of producing stable ternary graphite intercalation compounds, modifying anode solid electrolyte interphases, reducing the solubility of intermediates, and decreasing polarization. Better still, ether‐based electrolytes are compatible with specific inorganic cathodes and could catalyze the assembly of full SIBs prototypes. This Research News article aims to summarize the recent critical reports on ether‐based electrolytes in sodium‐based batteries, to unveil the uniqueness of ether‐based electrolytes to advancing diverse electrode materials, and to shed light on the viability and challenges of ether‐based electrolytes in future sodium‐based battery chemistries. 相似文献
72.
Chitosan functional properties 总被引:7,自引:0,他引:7
Chitosan is a partially deacetylated polymer of N-acetyl glucosamine. It is essentially a natural, water-soluble, derivative
of cellulose with unique properties. Chitosan is usually prepared from chitin (2 acetamido-2-deoxy β-1,4-D-glucan) and chitin
has been found in a wide range of natural sources (crustaceans, fungi, insects, annelids, molluscs, coelenterata etc.) However
chitosan is only manufactured from crustaceans (crab and crayfish) primarily because a large amount of the crustacean exoskeleton
is available as a by product of food processing. Squid pens (a waste byproduct of New Zealand squid processing) are a novel,
renewable source of chitin and chitosan. Squid pens are currently regarded as waste and so the raw material is relatively
cheap. This study was intended to assess the functional properties of squid pen chitosan. Chitosan was extracted from squid
pens and assessed for composition, rheology, flocculation, film formation and antimicrobial properties. Crustacean chitosans
were also assessed for comparison. Squid chitosan was colourless, had a low ash content and had significantly improved thickening
and suspending properties. The flocculation capacity of squid chitosan was low in comparison with the crustacean sourced chitosans.
However it should be possible to increase the flocculation capacity of squid pen chitosan by decreasing the degree of acetylation.
Films made with squid chitosan were more elastic than crustacean chitosan with improved functional properties. This high quality
chitosan could prove particularly suitable for medical/analytical applications.
This revised version was published online in November 2006 with corrections to the Cover Date. 相似文献
73.
Wenyan Zou Xiaoyu Liu Dianhua Chen Jie Wang Xi Zhao Jiahuang Li 《Preparative biochemistry & biotechnology》2016,46(8):833-837
Based on their nanocage architectures, ferritins show their potential applications in medical imaging and therapeutic delivery systems. However, the recombinant human H-chain ferritin (rHF) is prone to form inclusion bodies in Escherichia coli. In our study, the cDNA of rHF was cloned into plasmid pET28a under the control of a T7 promoter. Molecular chaperones, including GroES, GroEL, and trigger factor, were coexpressed with rHF to facilitate its correct folding. The results showed that the solubility of rHF was increased more than threefold with the help of molecular chaperones. Taking advantages of its N-terminal His-tag, rHF was then purified with Ni-affinity chromatography. With a yield of 15?mg/L from bacterial culture, the purified rHF was analyzed by circular dichroism spectrometry for its secondary structure. Moreover, the rHF nanocages were characterized by transmission electron microscopy and dynamic light scattering. Our results indicate that rHF is able to self-assemble into nanocages with a narrow size distribution. 相似文献
74.
Elder Pupo Behnam A. Baghbaderani Victoria Lugo Julio Fernández Rolando Páez Isis Torréns 《Biotechnology letters》1999,21(12):1119-1123
The streptokinase (SK) gene from S. equisimilis H46A (ATCC 12449) was cloned in E. coli W3110 under the control of the tryptophan promoter. The recombinant SK, which represented 15% of total cell protein content, was found in the soluble fraction of disrupted cells. The solubility of this SK notably differed from that of the product of the SK gene from S. equisimilis (ATCC 9542) which had been cloned in E. coli W3110 by using similar expression vector and cell growth conditions, and occurred in the form of inclusion bodies. 相似文献
75.
Escherichia coli maltose-binding protein is uncommonly effective at promoting the solubility of polypeptides to which it is fused. 总被引:15,自引:0,他引:15
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R. B. Kapust D. S. Waugh 《Protein science : a publication of the Protein Society》1999,8(8):1668-1674
Although it is usually possible to achieve a favorable yield of a recombinant protein in Escherichia coli, obtaining the protein in a soluble, biologically active form continues to be a major challenge. Sometimes this problem can be overcome by fusing an aggregation-prone polypeptide to a highly soluble partner. To study this phenomenon in greater detail, we compared the ability of three soluble fusion partners--maltose-binding protein (MBP), glutathione S-transferase (GST), and thioredoxin (TRX)--to inhibit the aggregation of six diverse proteins that normally accumulate in an insoluble form. Remarkably, we found that MBP is a far more effective solubilizing agent than the other two fusion partners. Moreover, we demonstrated that in some cases fusion to MBP can promote the proper folding of the attached protein into its biologically active conformation. Thus, MBP seems to be capable of functioning as a general molecular chaperone in the context of a fusion protein. A model is proposed to explain how MBP promotes the solubility and influences the folding of its fusion partners. 相似文献
76.
Devin Tesar Jacob Luoma Emily A. Wyatt Catherine Shi Whitney Shatz Philip E. Hass 《MABS-AUSTIN》2017,9(8):1297-1305
To date, ocular antibody therapies for the treatment of retinal diseases rely on injection of the drug into the vitreous chamber of the eye. Given the burden for patients undergoing this procedure, less frequent dosing through the use of long-acting delivery (LAD) technologies is highly desirable. These technologies usually require a highly concentrated formulation and the antibody must be stable against extended exposure to physiological conditions. Here we have increased the potential of a therapeutic antibody antigen-binding fragment (Fab) for LAD by using protein engineering to enhance the chemical and physical stability of the molecule. Structure-guided amino acid substitutions in a negatively charged complementarity determining region (CDR-L1) of an anti-factor D (AFD) Fab resulted in increased chemical stability and solubility. A variant of AFD (AFD.v8), which combines light chain substitutions (VL-D28S:D30E:D31S) with a substitution (VH-D61E) to stabilize a heavy chain isomerization site, retained complement factor D binding and inhibition potency and has properties suitable for LAD. This variant was amenable to high protein concentration (>250 mg/mL), low ionic strength formulation suitable for intravitreal injection. AFD.v8 had acceptable pharmacokinetic (PK) properties upon intravitreal injection in rabbits, and improved stability under both formulation and physiological conditions. Simulations of expected human PK behavior indicated greater exposure with a 25-mg dose enabled by the increased solubility of AFD.v8. 相似文献
77.
78.
The solubilization efficiency of N-methyl pyrrolidone (NMP) has been determined and compared to that of ethanol and propylene glycol for 13 poorly soluble drugs.
NMP is found to be a more efficient solubilizer for all the drugs studied. The solubility enhancement as high as about 800-fold
is obtained in 20% v/v NMP solution as compared to water. The mechanism of drug solubilization by NMP has also been investigated. It is proposed
that NMP enhances drug solubility by simultaneously acting as a cosolvent and a complexing agent. A mathematical model is
used to estimate the drug solubility in NMP–water mixture, according to which the total solubility enhancement is a sum of
the two effects. This model describes the experimental data well and is more accurate than other models. A large and uniform
reduction in the surface tension of water as a function of NMP concentration demonstrates its cosolvent effect. The complexation
is supported by the fact that it’s strength is affected by the temperature and the polarity of the medium. A strong correlation
exists between log K
ow of the drugs and the cosolvency coefficients. The correlation between log K
ow and the complexation coefficients is weak suggesting that factors such as molecular shape and aromaticity of the drug molecule
are significant in determining the complexation strength. This has been confirmed by the absence of a significant complexation
between NMP and linear drug-like solutes. 相似文献
79.
The objective of the present investigation was to study the influence of size, nature, and topology of substituents on the
thermodynamic characteristics of sublimation, fusion, solubility, solvation, and partitioning processes of some drug and druglike
molecules. Thermodynamic functions of sublimation process 2-acetaminophen and 3-acetaminophen were obtained on the basis of
temperature dependencies of vapor pressure by the transpiration method. Thermodynamic characteristics of solubility processes
in water, n-octanol, and n-hexane were calculated from the temperature dependencies of solubility using the solubility saturation method. For evaluation
of fusion parameters, differential scanning calorimetry was used. A new approach to distinguishing specific and nonspecific
energetic terms in the crystal lattice was developed. Specific and nonspecific solvation terms were distinguished using the
transfer from the “inert” n-hexane to the other solvents. For the acetaminophen compounds and for some related drug molecules, the correlation between
melting points and a parameter describing the ratio between specific and nonspecific interaction in the crystal lattices was
obtained. A diagram enabling analysis of the mechanism of the partitioning process was applied. It was found that for isomers
of benzoic acids and for acetaminophens, the position of substituents affects the mechanism of the partitioning process but
not the extent of partitioning ( values). In contrast to this, an increased size of substituents (parabens) leads to essential changes in values, but the mechanism of the partitioning process stays the same. 相似文献
80.
Preformulation studies were performed on a hemiglutarate ester prodrug of Δ9-tetrahydrocannabinol (THC-HG), to facilitate the development of stable formulations by hot-melt methods. The various studies
performed included solid-state thermal characterization, pKa, logP, aqueous and pH dependent solubility, pH stability and
effect of moisture, temperature and oxygen on solid-state stability. A hot-melt method was utilized to fabricate THC-HG incorporated
poly (ethylene oxide) (PEO) matrices and the bioadhesive properties, release profiles and post-processing stability of these
matrices were assessed as a function of the polymer molecular weight. The prodrug exhibited a T
g close to 0°C, indicating its amorphous nature. Thermogravimetric analysis revealed a rapid weight loss after 170°C. The prodrug
exhibited a seven-fold higher aqueous solubility as compared to the parent drug (THC). Also, the solubility of the compound
increased with increasing pH, being maximum at pH 8. The prodrug exhibited a v-shaped pH-rate profile, with the degradation
rate minimum between pH 3 and 4. The moisture uptake and drug degradation increased with an increase in relative humidity.
Solid-state stability indicated that the prodrug was stable at −18°C but demonstrated higher degradation at 4°C, 25°C and
40°C (51.6%, 74.5% and 90.1%, respectively) at the end of 3-months. THC-HG was found to be sensitive to the presence of oxygen.
The release of the active from the polymeric matrices decreased, while bioadhesion increased, with an increase in molecular
weight of PEO. 相似文献