Study on surface enhanced Raman scattering of Au and Au@Al2O3 spherical dimers based on 3D finite element method.

In this paper, the surface enhanced Raman scattering (SERS) characteristics of Au and Au@Al2O3 nanoparticle dimers were calculated and analyzed by using finite element method (3D-FEM). Firstly, the electric field enhancement factors of Au nanoparticles at the dimer gap were optimized from three aspects: the incident angle of the incident light, the radius of nanoparticle and the distance of the dimer. Then, aluminum oxide is wrapped on the Au dimer. What is different from the previous simulation is that Al2O3 shell and Au core are regarded as a whole and the total radius of Au@Al2O3 dimer is controlled to remain unchanged. By comparing the distance of Au nucleus between Au and Au@Al2O3 dimer, it is found that the electric field enhancement factor of Au@Al2O3 dimer is much greater than that of Au dimer with the increase of Al2O3 thickness. The peak of electric field of Au@Al2O3 dimer moves towards the middle of the resonance peak of the two materials, and it is more concentrated than that of the Au dimer. The maximum electric field enhancement factor 583 is reached at the shell thickness of 1 nm. Our results provide a theoretical reference for the design of SERS substrate and the extension of the research scope.

Iridium(III)-Catalyzed C-H Amidation/Cyclization of NH-Sulfoximines with N-Alkoxyamides: Formation of Thiadiazine 1-Oxides.

The first example of Ir(III)-catalyzed C-H activation/cyclization with N-alkoxyamides as amidation reagents to simultaneously form functionalized thiadiazine 1-oxide derivatives was developed. This one-pot cascade protocol tolerated diverse functional groups and readily constructed various heterocyclic frameworks in moderate to good yield.

Specific Synthesis of 3H-Indole Derivatives via Rh(III)-Catalyzed Cascade Annulation between N-Phenylbenzimidamides and Pyridotriazoles.

An efficient synthetic method to construct 3H-indole derivatives has been successfully developed involving rhodium-catalyzed highly selective C-H bond activation of N-phenylbenzimidamides and subsequent couplings with pyridotriazoles. This cascade approach features excellent chemoselectivity and unique of products containing quaternary carbon center with the pyridyl moiety.

Dragonfly wing decorated by gold nanoislands as flexible and stable substrates for surface-enhanced Raman scattering (SERS).

A flexible and stable biomimetic SERS substrate was successfully fabricated by depositing gold (Au) nanoislands on the dragonfly wings (DW) via a simple DC magnetron sputtering system. Characterizations of the Au/DW nanostructure indicated that the optimum Au/DW-45 (sputtering time was 45 min) substrate owns high sensitivity, good stability and outstanding reproducibility. The limit of detection (LOD) for Rhodamine 6 G (R6G) was as low as 10-7 M and enhancement factor (EF) was calculated to be 2.8 × 106. 70-day-duration stability tests showed that Raman intensity of R6G reduced only by 12.9% after aging for 70 days. The maximum relative standard deviations (RSD) of SERS intensities from 100 positions of Au/DW-45 substrate were less than 8.3%, revealing outstanding uniformity and reproducibility. Moreover, the flexible Au/DW-45 bioscaffold arrays were employed to solve the vital problem of pesticide residues. By directly sampling from tomato peels via a "press and peel off" approach, cypermethrin has been rapidly and reliably determined with a LOD centered at 10-3 ng/cm2 and a correlation coefficient (R2) of 0.987. The positive results demonstrated that the Au-based DW biomimetic arrays may offer an efficient SERS platform for the identification of various pesticide residues on real samples.

Density-matrix evaluation of the enhancement to resonant Raman scattering and fluorescence of molecules confined in metallic nanoparticle dimers.

In the present work we study the surface-enhanced resonant Raman scattering (SERRS) and fluorescence (SEF) spectra of a general model molecule confined in metallic dimers consisting of Ag, Au and hybrid AuAg nanoparticles (NPs). The electromagnetic (EM) enhancement factors were simulated by the generalized Mie scatting method and the scattering cross section of the molecules were obtained by density-matrix calculations. The influence of the size of the NPs and the separation between the dimer on the Raman scattering and fluorescence were systematically studied and analyzed in detail. It was found that the SERRS mainly related to EM enhancement and the SEF depended on the competition between EM enhancement and quantum yield, both of which could be controlled by tuning the radius and separation of the metallic dimers. The optimal radius of the NPs for SERRS were found to be around 30 nm for AgNPs, 40 nm for AuNPs and 50 nm for hybrid AuAgNPs. The strongest Raman enhancement as predicted by the theoretical simulations were 6.2 × 1010, 1.5 × 107 and 5.2 × 108 for the three types of structures, respectively. These results could offer valuable information for the design of metallic substrates for surface enhanced Raman and fluorescence measurements.

Association of HLA-DRB1, HLA-DQB1 Polymorphisms with HPV 16 E6 Variants among Young Cervical Cancer Patients in China.

Potential correlation of human papillomavirus (HPV) 16 E6 variants and human leukocyte antigen (HLA) class II polymorphisms has been suggested in patients with cervical cancer, so far little information is available about the possible interaction between E6 variants and HLA class II variability during the obviously accelerated progression to cervical cancer in young women. In this study, we aimed to explore the association between the HPV16 E6 variants and HLA-DRB1, DQB1 alleles in a Chinese young cervical cancer population. The HLA-DRB1, HLA-DQB1 polymophisms were genotyped by low-resolution polymerase chain reaction (PCR) with sequence-specific primer. HPV16 E6 DNA was tested by Sanger fluorescent dye dideoxy-termination technique. The difference of DRB1, DQB1 polymorphisms between young cervical cancer patients (≤35ys, n=61) and older ones (>35ys, n=85) and the association with E6 variants were analyzed. Results showed that the distribution pattern of HLA-DRB1, DQB1 alleles was different between young cervical cancer patients and older ones. The allele frequency of DQB1*0501 in young patients was significantly lower than older ones (6.6% vs. 23.5%, p<0.05). The HPV16 E6 A4 lineage was the exclusive type observed in young patients, and its prevalence was significantly higher than that of older cases (82.86% vs.41.94%, p<0.05). DRB1*03 was not found in young patients positive for the HPV16 E6 A4 lineage, whereas it was observed in 19.2 % older patients with A4 positive(Pc<0.05). In conclusion, specific association between certain HPV16 E6 variant and genetic polymorphisms of HLA may play a role during the progression of early onset cervical cancer in young patients. Certain HLA-DRB1 and HLA-DQB1 alleles may be related to the A4 lineage among young cervical cancer patients, which was the unique HPV16 E6 variant found in Chinese young patients. Our finding may provide an insight into the pathogenic factors that associated with cervical cancer in young women.

Domain Motions and Functionally-Key Residues of L-Alanine Dehydrogenase Revealed by an Elastic Network Model.

Mycobacterium tuberculosis L-alanine dehydrogenase (L-MtAlaDH) plays an important role in catalyzing L-alanine to ammonia and pyruvate, which has been considered to be a potential target for tuberculosis treatment. In the present work, the functional domain motions encoded in the structure of L-MtAlaDH were investigated by using the Gaussian network model (GNM) and the anisotropy network model (ANM). The slowest modes for the open-apo and closed-holo structures of the enzyme show that the domain motions have a common hinge axis centered in residues Met133 and Met301. Accompanying the conformational transition, both the 1,4-dihydronicotinamide adenine dinucleotide (NAD)-binding domain (NBD) and the substrate-binding domain (SBD) move in a highly coupled way. The first three slowest modes of ANM exhibit the open-closed, rotation and twist motions of L-MtAlaDH, respectively. The calculation of the fast modes reveals the residues responsible for the stability of the protein, and some of them are involved in the interaction with the ligand. Then, the functionally-important residues relevant to the binding of the ligand were identified by using a thermodynamic method. Our computational results are consistent with the experimental data, which will help us to understand the physical mechanism for the function of L-MtAlaDH.

Prediction of allosteric sites on protein surfaces with an elastic-network-model-based thermodynamic method.

Allostery is a rapid and efficient way in many biological processes to regulate protein functions, where binding of an effector at the allosteric site alters the activity and function at a distant active site. Allosteric regulation of protein biological functions provides a promising strategy for novel drug design. However, how to effectively identify the allosteric sites remains one of the major challenges for allosteric drug design. In the present work, a thermodynamic method based on the elastic network model was proposed to predict the allosteric sites on the protein surface. In our method, the thermodynamic coupling between the allosteric and active sites was considered, and then the allosteric sites were identified as those where the binding of an effector molecule induces a large change in the binding free energy of the protein with its ligand. Using the proposed method, two proteins, i.e., the 70 kD heat shock protein (Hsp70) and GluA2 alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptor, were studied and the allosteric sites on the protein surface were successfully identified. The predicted results are consistent with the available experimental data, which indicates that our method is a simple yet effective approach for the identification of allosteric sites on proteins.

[Study of Dioscorea opposita Thunb from different producing areas with XRF and PXRD].

The contents of various elements in rhizoma dioscoreae were analyzed and compared with those of shishou D. opposita Thunb on the whole jointly by XRF and PXRD. The results showed that the element Cu, Al and Mn could not be detected in rhizoma dioscoreae, but the element Mg, Zn and Cr were found, and other elements contents changed to different degrees; there are starch and whewellite in both groups, the crystal type of starches separated from rhizoma dioscoreae cultivars was a typical B-type pattern, but as C-type and V-type in shishou D. opposita Thunb, which is a mixture of A-type, B-type and V-type. The combination of two testing techniques could be applied to the mensuration and analysis of the elements and micro-structural of Dioscorea opposita Thunb which could be from different producing areas.

[Analysis of the 4th generation outer space bred Angelica dahurica by FTIR spectroscopy].

The major components of the 4th generation outer space bred angelica and the ground group were determined and analyzed by Fourier transform infrared spectroscopy (FTIR) and second derivative spectrum, considering the large mutation of the plants with space mutagenesis. The results show that the content of the coumarin (1741 cm(-1)), which is the main active components of the space angelica dahurica increased, and the content of the protein (1 459, 1 419 cm(-1)) and the fat (930 cm(-1)) increased slightly, whereas the content of the starch and the dietary fiber reduced drastically. There are obvious differences between the peak values of the second derivative spectra of the plants, revealing that the outer space angelica dahurica contained amine component at 1 279 cm(-1). Space mutation breeding is favor of breeding angelica with better idiosyncrasy.

[Analysis of atractylodes macrocephala koidz of spaceflight breeding with XRF and PXRD].

The contents of various elements in the fourth generation atractylodes macrocephala koidz cultivated by spaceflight breeding were analyzed and compared with those of the ground group on the whole jointly by XRF and PXRD. The results showed that the element Na and Ti could not be detected in the space group, and the levels of K and Mn were enhanced by 1.16 and 1.15 times as these elements were measured in ground group, but other elements' contents declined to different degrees, and the most notable elements are Si and P, decreasing by 82.1% and 71.2% accordingly; there is some whewellite in the ground group, whereas much less is found in the space group. The ground group contains inulin, however none in the space group. Spaceflight breeding can harvest significantly mutated specific Chinese herbal medicines varieties. The combination of two testing techniques has a positive role in space breeding applied in cultivation of medicinal plants.

[Application of XRF to the analysis of Scutellaria baicalensis with space mutagenesis].

X-ray fluorescence spectrum (XRF) analytic method was applied to the determination of the contents and varieties of mineral elements in the space flight mutagenesis breeding scutellaria baicalensis Georgi, and compared with the ground group which were planted and collected together under the same conditions, in an attempt to search for the influence of space environment upon mutation on scutellaria baicalensis Georgi. The result indicates that the varieties of the main mineral elements in the two samples are samely basically, therefore, the two samples have same absorption and enrichment capability of specific element, but the contents of elements Ca, Na, Zn and S increase by 0.3, 0.3, 0.04 and 0.7 times, respectively, in the space group. This modern testing method played an important role in the study. It is recommended that the testing method should be used in the selection of space bred herbal seeds for its advantages, such as quick, simple, highly sensitive, and of wide measure range. To conclude, New breeds can be selected by space breeding, it is significant for the selection and growing of space herbal medicine seeds, and it also has broad application in space breeding of medical plants.

Human papillomavirus type 16 e6 gene variations in young Chinese women with cervical squamous cell carcinoma.

Human papillomavirus (HPV) 16 E6 gene mutation is considered an important genetic change in cervical lesion progression. To explore the possible association of specific HPV16 E6 sequence variations with the development of invasive cervical squamous cell carcinoma (SCC) in young women, we examined the distribution of HPV16 E6 variants in a Chinese cervical SCC population and analyzed the difference between younger patients (≤35 years, n = 50) and older ones (>35ys, n = 71). Human papillomavirus type 16 E6 DNA was amplified by polymerase chain reaction and sequenced by Sanger fluorescent dye dideoxy-termination method. Analysis revealed that the most frequently found variation in this Chinese population was the EV (As) lineage (65.45%). In addition, the EV (As) lineage seems more common and uniform in younger patients than other lineages, and it may be associated with early age at diagnosis of cervical SCC in young women.

[Comprehensive characterization of main components and microstructures in five different species of Salvia miltiorrhiza bge].

Studied with X-ray fluorescence spectrum analytic (XRF), powder X-ray diffraction (PXRD) and Fourier transform infrared spectroscopy (FTIR) for five different species of Salvia miltiorrhiza bge grew in Anguo, the intrinsic components and microstructures were determined and comprehensive characterization was carried out. The figure of comprehensive characterization can describe characteristics of intrinsic components from elements, crystal and amorphous active component, it can give an intuitive description for the same components and subtle differences in the intrinsic components of Salvia miltiorrhiza bge, which are different idioplasmatic and same species. It is the ideal method because of the simple preparation of sample, rapid and fine accurate measurement with reproducibility and objectivity, so that it can be used for breeding of fine varieties of Chinese medicinal materials, Chinese medicinal materials GAP guidance of growing conditions, medicinal origin characteristics, the intrinsic composition and microstructure characterization, quality control and authenticity of the identification.

[Study of the fourth generation of Salvia miltiorrhiza Bge by XRF].

X-ray fluorescence spectrum (XRF) analytic method was used to analyze and compare the contents and varieties of mineral elements in the ground group Salvia miltiorrhiza Bge, and the fourth generation Salvia miltiorrhiza Bge with space flight mutagenesis breeding in order to provide important basic data for selecting high quality breed and further research. The result indicates that the varieties of the main mineral elements in the two samples are the same basically, but Cu/Zn ratio is enhanced to 1.0, the contents of microelements Cr, Mn and Fe increase by 0.6, 0.5, and 0.3 times respectively compared with the ground group. To conclude, in the space group the contents and proportions of the mineral elements are improved and optimized. Xray fluorescence spectrum analytic method has many advantages, such as quickness, simplicity, high sensitivity, wide measure range, etc. The method can be used for quantitative element analysis and study of Chinese herbal medicines.

[Research on the fourth generation of radix isatidis by FTIR].

FTIR spectra of fourth-generation space bred radix isatidis and FTIR spectra of radix isatidis in a ground group were determined on the whole. Comparative analysis was conducted on main constituents (components) to accumulate data for comprehensively understanding and thoroughly studying the inherent property, and to explore a method of evaluating the quality of space bred radix isatidis. The results showed that slight difference existed in the positions and shapes of the absorption peaks in FTIR spectra of samples between the two groups. The intensities of main absorption peaks of radix isatidis in the space group were strengthened to various degrees compared with those in the ground group. The absorption peaks were markedly enhanced at wave numbers of 1 047, 1 630 and 1 412 cm(-1), indicating that the contents of polysaccharides, sterides, triterpenes and flavanoids, particularly polysaccharides with anti-viral efficacy, increased to different extents. The absorption peak intensity of space radix isatidis at the wave number of 1 745 cm(-1) was weakened compared with that of radix isatidis in the ground group, suggesting the reduction of glycosides and organic acids. It is concluded that the contents of a plurality of active components of radix isatidis in the space group are elevated. New radix isatidis varieties with high contents of diverse active components can be harvested by spaceflight mutation breeding.

[Study of the Saposhnikovia divaricata with space mutagenesis by Fourier transform infrared spectroscopy].

The outer space Saposhnikovia divaricata of the fourth generation was studied and compared with the ground group and comparison group for the first time. The intensity of carbonyl absorption peak at 1640 cm(-1) is stronger than the other two, indicating that chromone content was enhanced obviously. The peaks at 2927 and 2856 cm(-1) were assigned to --CH2-- groups, the peak at 1050 cm(-1) was due to the C-O groups, and the intensities at 2927, 2856 and 1050 cm(-1) were stronger than other samples, indicating that polysaccharide and glycoside contents were enhanced obviously. The intensity of lactone absorption peak at 1743 cm(-1) was stronger than the ground group and weaker than the comparison, indicating that coumarin content was higher than ground group and lower than the comparison. The major components and the structures remained intact, and the effective component contents were enhanced in the outer space Saposhnikovia divaricata. Using FTIR can analyse and characterize the intrinsic quality of the outer space medicinal materials.

[Research on the fourth generation of Saposhnikovia divaricata by XRF].

To cultivate oriented new varieties, Saposhnikovia divaricata seeds were carried by Shenzhou "3" satellite and filtered when they were being brought back. In the present paper, X-ray fluorescence(XRF) was used to mensurate and analyze the contents of elements of the two samples from the ground group and the 4th generation of space Saposhnikovia divaricata (space group) that have advantages in branches and leaves and yields. The contents of the main mineral elements in the two samples are the same basically. But the contents of the elements Zn, Fe, Mn and Cu from the outer group are higher than the ground group. Especially the contents of Zn, Fe, Mn and Cu concerning the curative effect in the space group increase 4.39, 1.23, 0.84 and 0.9 times as compared to the ground group. In the space group the contents and proportions of the mineral elements are improved and optimized. XRF method can be used for overall element analysis of and research on Chinese herbal medicines. Space flight breeding is an effective method for the selection of new Saposhnikovia divaricata breed.

[Analysis and characterization of Belamcanda chinensis with space mutagenesis breeding by X-ray fluorescence analysis and X-ray diffraction].

The contents of various elements in the fourth generation Belamcanda chinensis (L.) DC. with space mutagenesis breeding were analyzed and characterized. X-ray fluorescence spectrum analysis (XRF) and powder X-ray diffraction (PXRD) were applied jointly. It was found that the content of K element in the space flight mutagenesis increases 1.03 and 0.31 times, Mg enhances 1.44 and 0.06 times, but Al reduces 38.5% and 85.5% respectively compared to the contents in the ground group and the comparison group, while those of Ca, Mn and Fe enhance 0.95, 0.30 and 0.29 times respectively contrasted to the ground group. Besides, there was discovered the crystal of whewellite in the Belamcanda chinensis (L.) DC. and the content in the ground group is less than that of the outer space and the outer space group, which in turn is less than that of the comparison group. It is concluded that the contents of mineral elements indispensable to body in the space group are closer or superior to the comparison, group as compared to the ground group. In the present paper, a quick and simple appraising method is offered, which may be of great significance to the popularization of the planting outer space Chinese traditional medicine to filtrate more excellent breed and set up norm of quality appraisal.

[Measurement and analysis of platycodon grandiflorum with space flight mutagenesis breeding by XRF].

X-ray fluorescence spectrum (XRF) analytic method was used to analyze and compare the contents of various mineral elements in the ground group platycodon grandiflorum, the comparison group platycodon grandiflorum and the fourth generation platycodon grandiflorum with space flight mutagenesis breeding. The result indicated that the contents of microelements Zn, Mn and Fe in the outer space group increase by 1.9, 2.4 and 0.6 times respectively, compared with those in the ground group. Microelements Zn, Mn and Fe concern curative effect such as expectorant effect in the Chinese traditional medicine. And the elements Zn and Mn increase by 0.6 and 1.9 times respectively, compared with the comparison group. The outer space group is closer and/or superior to the comparison group compared with the ground group. To conclude, the performance of the outer space group platycodon grandiflorum was upgraded obviously. X-ray fluorescence spectrum analytic method has many advantages, such as quickness, simpleness, high sensitivity, wide measure range, and easy reappearance etc. The method could be applied to the mensuration and analysis of the other traditional Chinese medicines which could be ground into powder.