Search

Magnetic hyperthermia therapy (MHT) is a highly promising therapeutic modality, mainly applied to deal with cancers and malignant tumors. To gain efficient magnetic hyperthermia therapy, magnetic nanoparticles (Fe3O4) with improved heating efficiency are necessary. In this work, magnetite nanoparticles anchored on graphene oxide (GO/Fe3O4) have been synthesized via chemical precipitation method, and anti-cancer drug have been introduced to form GO/Fe3O4 loaded with doxorubicin hydrochloride (GO/Fe3O4-DXR) composite nanoparticles. X-ray diffraction analysis has been carried out to characterized the crystal structure of GO/Fe3O4 nanoparticles with different mass ratios. Fourier transform infrared spectroscopy (FTIR) confirmed the presence of doxorubicin hydrochloride (DRX) in GO/Fe3O4-DXR, while the structure of GO/Fe3O4 nanoparticles with different mass ratios are studied by Transmission electron microscopy (TEM). And the heating efficacy of GO/Fe3O4-DXR nanoparticles were. investigated suitable for magnetic hyperthermia therapy under safe alternating magnetic fields (80 kHz, 30 kA m−1). Besides, the DXR loading and release data of GO/Fe3O4-DXR have been tested via ultraviolet–visible spectroscopy (UVVIS) in presence of the AC field. The above characteristics conform to temperature requirements of magnetic materials on medical applications, which infers that GO/Fe3O4 -DXR particles show promising talent as targeted drug carriers and thermoseeds in MHT.

Silicon, to be a potential anode material of LIBs, possesses a pretty high lithium storage capacity. However, the structural integrity can be destructed by its huge volume expansion through cycles, which results in a large capacity attenuation. Meanwhile, the poor electrochemical performance of silicon-based anodes can be attributed to its poor conductance which reduces the reaction kinetics. According to the above challenges, core-shell structured silicon-nickel nanoparticles have been dispersed on 3D intertwined carbon nanotube networks (Si@Ni-NP/CNTs) via nitric acid pre-treatment and amino functionalization. The nickel-plated shell outside silicon core nanoparticles (Si@Ni-NP) can play a certain supporting role to prevent the volume expansion of silicon, which finally brings down the degree of powdering. Especially, the 3D framework composed of intertwined carbon nanotubes can efficiently provide not only an ample buffer space during intercalation/deintercalation but also a more stable conductive network to increase ion/electron transfer rate. Due to the above improvements in structural stability and reaction kinetics, Si@Ni-NP/CNTs reveal a reversible capacity of 1008 mAh g−1 with a 98% capacity retention over 100 cycles at a current density of 100 mA g−1. Under different current densities in rate test, the specific capacity recovery rate can reach 92%. The novel structure enables Si@Ni-NP/CNTs excellent stability under cycles and various rates, as a promising anode material of LIBs.

Lithium-sulfur batteries are considered to be an ideal high-performance rechargeable lithium battery. However, some problems have seriously hindered the practical application of lithium-sulfur batteries. A simple one-step hydrothermal method has been applied to design nitrogen-doped graphene aerogel (N-GA) with three different nitrogen sources. Subsequently, sulfur was encapsulated in N-GA by chemical deposition method to synthesize sulfur encapsulated in N-GA (N-GA/S) composites. Among them, the N-GA1/S composite with sulfur content reaching 75.5 wt% has a discharge specific capacity of 723.9 mAh g−1 after 100 cycles at 0.7 C, and the capacity retention rate is up to 87.4% while the coulombic efficiency still remains 98%. The outstanding electrochemical performance is owing to the good coating of sulfur by nitrogen-doped graphene aerogel, the improvement of the conductivity of the graphene skeleton by nitrogen doping, and the strong adsorption capacity of the doped nitrogen atom to lithium polysulfide. The graphene skeleton also helps to reduce the volume effect while charging and discharging. Furthermore, the proportion of pyridinic-N in N-GA1/S composites is higher than that in the two other composites, and it has a better adsorption capacity for lithium polysulfide.

Owing to the high energy density and rich resource, Li–S batteries are now considered as a promising direction in energy storage. Nevertheless, the electrochemical properties of sulfur host materials have been limited by the large volume changes during cycles, the dissolution of polysulfides in an electrolyte, and the insulating properties of lithium polysulfides. Based on the above conclusions, a novel cathode material of graphene nanosheet@spherical ordered mesoporous carbon/sulfur nanocomposite (GNs@s-OMC/S) where s-OMC/S was wrapped by GNs has been synthesized in this article and delivers superior cycle stability. According to the tests, GNs@s-OMC/S provides a capacity of 1159 mAh g−1 at a 0.4 C discharge rate. In addition, even at a high rate of 4 C, the discharge capacity of GNs@s-OMC/S can also remain 767 mAh g−1, representing a fantastic rate performance and high specific capacity. It can be ensured that the narrow channels provided by s-OMC and the graphene entrapment with high conductivity enhance the electrochemical performance of the cathode.

Optically active β-amino alcohols are very useful chiral intermediates frequently used in the preparation of pharmaceutically active substances. Here, a novel cyclohexylamine oxidase (ArCHAO) was identified from the genome sequence of Arthrobacter sp. TYUT010-15 with the R-stereoselective deamination activity of β-amino alcohol. ArCHAO was cloned and successfully expressed in E. coli BL21, purified and characterized. Substrate-specific analysis revealed that ArCHAO has high activity (4.15 to 6.34 U mg-1 protein) and excellent enantioselectivity toward the tested β-amino alcohols. By using purified ArCHAO, a wide range of racemic β-amino alcohols were resolved, (S)-β-amino alcohols were obtained in >99 % ee. Deracemization of racemic β-amino alcohols was conducted by ArCHAO-catalyzed enantioselective deamination and transaminase-catalyzed enantioselective amination to afford (S)-β-amino alcohols in excellent conversion (78-94 %) and enantiomeric excess (>99 %). Preparative-scale deracemization was carried out with 50 mM (6.859 g L-1 ) racemic 2-amino-2-phenylethanol, (S)-2-amino-2-phenylethanol was obtained in 75 % isolated yield and >99 % ee.

A novel one-pot epoxide hydrolase/alcohol dehydrogenase/transaminase cascade process for the asymmetric ring opening of racemic epoxides to enantiopure β-amino alcohols is reported. The product (S)-β-amino alcohols were obtained in 97–99% ee and 79–99% conversion from readily available racemic epoxides.

The biological effects of nanoparticles are of great importance for the in-depth understanding of safety issues in biomedical applications. Induction of autophagy is a cellular response after nanoparticle exposure. Bismuth sulfide nanoparticles (Bi2S3 NPs) are often used as a CT contrast agent because of their excellent photoelectric conversion ability. Yet there has been no previous detailed study other than a cell toxicity assessment. In this study, three types of Bi2S3 NPs with different shapes (Bi2S3 nano rods (BSNR), hollow microsphere Bi2S3 NPs (BSHS) and urchin-like hollow microsphere Bi2S3 NPs (ULBSHS)) were used to evaluatecytotoxicity, autophagy induction, cell migration and invasion in human hepatocellular carcinoma cells (HepG2). Results showed that all three Bi2S3 NPs lead to blockage in autophagic flux, causing p62 protein accumulation. The cell death caused by these Bi2S3 NPs is proved to be autophagy related, rather than related to apoptosis. Moreover, Bi2S3 NPs can reduce the migration and invasion in HepG2 cells in an autophagy-dependent manner. ULBSHS is the most cytotoxic among three Bi2S3 NPs and has the best tumor metastasis suppression. These results demonstrated that, even with relatively low toxicity of Bi2S3 NPs, autophagy blockage may still substantially influence cell fate and thus significantly impact their biomedical applications, and that surface topography is a key factor regulating their biological response.

The use of the phenicol antibiotic florfenicol in livestock can select for the optrA gene, which also confers resistance to the critically important oxazolidinone antibiotic linezolid. However, the occurrence and dissemination of florfenicol and linezolid cross-resistance genes in anaerobic treatment systems for livestock waste are unknown. Herein, the phenotypes and genotypes (optrA, fexA, fexB, and cfr) of florfenicol and linezolid cross-resistance were investigated in 339 enterococci strains isolated from lab- and full-scale mesophilic anaerobic digestion systems treating swine waste. It was found that optrA, fexA, and fexB were frequently detected in isolated enterococci in both systems by PCR screening, whereas cfr was not detected. The most abundant gene was optrA, which was detected in 73.5% (n = 50) and 38.9% (n = 23) of enterococci isolates in the full-scale influent and effluent, respectively. Most strains carried more than two resistance genes, and the average percentage of co-occurrence of optrA/fexA was 16.6%. Based on minimum inhibitory concentrations of the enterococci strain phenotypes, 85.7%, 77.5%, and 77.5% of strains in influent were resistant to chloramphenicol, florfenicol, and linezolid, respectively, while 56.3%, 65.2%, and 13% in the effluent isolates were found, respectively, which was consistent with the genotype results. The phenotypes and genotypes of florfenicol and linezolid resistance were relative stable in the enterococci isolated from the influent and effluent in lab-scale anaerobic digestion system. The findings signify the enterococci isolates harboring the optrA gene remained in effluents of both full- and lab-scale swine waste anaerobic digestion system; hence, effective management strategies should be implemented to prevent the discharge of antibiotic resistance from the livestock waste treatment systems.

To screening of bacteria with cyclic amino alcohol deamination activity for enantioselective synthesis of chiral cyclic β-amino alcohols. A new strain named Arthrobacter sp. TYUT010-15 with the (R)-selective deamination activity of cyclic β-amino alcohol has been isolated from nature via a high throughput solid-phase screening method. The reaction conditions of TYUT010-15 were optimized. Using the resting cell of TYUT010-15 as the catalyst, kinetic resolution of trans-2-aminocyclopentanol, trans-2-aminocyclohexanol and cis-1-amino-2-indanol was carried out to afford (1S, 2S)-trans-2-aminocyclopentanol, (1S, 2S)-trans-2-aminocyclohexanol and (1R, 2S)-cis-1-amino-2-indanol in > 99% ee and 49.6–50% conversion. Four aromatic β-amino alcohols and two amines were also resolved, (S)-β-amino alcohols and (R)-amines were obtained in > 99% ee. Preparation experiment was conducted with 200 mM (23.2 g L−1) racemic trans-2-aminocyclohexanol, yielding the desired (1S, 2S)-trans-2-aminocyclohexanol in 40% isolated yield, > 99% ee and 5.8 g L−1 d−1 space time yields. This study provides a high throughput solid-phase method for screening of bacteria with cyclic amino alcohol deamination activity and a first example for practical preparation of chiral cyclic β-amino alcohol by Arthrobacter sp. TYUT010-15.

We in this paper derive the expression of the least square solution with the least norm to the system of generalized Sylvester quaternion matrix equations $$\begin{aligned} A_1X = E_1 ,\quad XB_1 = E_2, \quad C_1Y = E_3 ,\quad YD_1 = E_4,\quad A_2XB_2+C_2YD_2=E_5, \end{aligned}$$ where X, Y are unknown quaternion matrices and the others are given quaternion matrices.

Rationally surface optimization is considered to improve both energy capacity and structure stability in rechargeable batteries. A novel structure of copper coated silicon nanoparticles encapsulated in carbon cages (Si@Cu@CC) is synthesized by feasible methods of reduction and pyrolysis. The obtained composite exhibits a superior reversible capacity of 1724.3 mAh g−1 after 50 cycles at 0.1 A g−1, and the coulombic efficiency (CE) is 98.13%. It also maintains 1201.6 mAh g−1 even at the current density of 2 A g−1. The copper shell as a mechanical support layer wraps around the silicon nanoparticle can relieve the inner stress caused by the volumetric change. The exterior of Si@Cu particles is continuous network of carbon cages, which not only improves the conductivity of electrodes but also provides abundant transport channels for electrons and ions. The particular structure and the synergistic effect of copper and carbon have very important influence on the gorgeous properties of this composites.

In the field of speed sensorless control of permanent magnet synchronous motors, it is difficult to accurately estimate the speed via a single algorithm for full speed range because there are many non-ideal factors when the algorithms are realized. In this paper, high frequency pulse signal injection method is applied in the low speed region, and dual EKF is used in the medium and high speed region. The switching of these two algorithms is achieved by the weighted averaging rule. This hybrid estimation strategy avoids detecting the back-electromotive force which is hard to be measured in low-speed region, and also avoids the adverse effects of the filter delay in the mid-high speed region. Therefore, it enables the sensorless control effective over the full speed range. Moreover, the dual EKF algorithm can estimate the motor parameters with a relatively small amount of calculation. Validity and effectiveness of the proposed scheme is shown in the simulation results.

To quantify regional sources contributing to submicron particulate matter (PM1) pollution in haze episodes, on-line measurements combining two modeling methods, namely, positive matrix factorization (PMF) and backward Lagrangian particle dispersion modeling (LPDM), were conducted for the period of one month in urban Nanjing, a city located in the western part of Yangtze River Delta (YRD) region of China. Several multi-day haze episodes were observed in December 2013. Long-range transport of biomass burning from the southwestern YRD region largely contributed to PM1 pollution with more than 25% of total organics mass in a lasting heavy haze. The LPDM analysis indicates that regional transport is a main source contributing to secondary low-volatility production. The high-potential source regions of secondary low-volatility production are mainly located in areas to the northeast of the city. High aerosol pollution was mainly contributed by regional transport associated with northeastern air masses. Such regional transport on average accounts for 46% of total NR-PM1 with sulfate and aged low-volatility organics being the largest fractions (>65%).