Crystallographic Characterization of II–VI Semiconducting Nanostructures via Optical Second Harmonic Generation

We demonstrate the utility of optical second harmonic generation (SHG) polarimetry to perform structural characterization of noncentrosymmetric, single-crystalline II–VI semiconducting nanowires, nanobelts, and nanoflakes. By analyzing anisotropic SHG polarimetric patterns, we distinguish between wurtzite and zincblende II–VI semiconducting crystal structures and determine their growth orientation. The crystallography of these nanostructures was then confirmed via transmission electron microscopy measurements performed on the same system. In addition, we show that some intrinsic material properties such as nonlinear coefficients and geometry-dependent optical in-coupling coefficients can also be determined from the SHG experiments in WZ nanobelts. The ability to perform SHG-based structural characterization and crystallographic study of II–VI semiconducting single-crystalline nanomaterials will be useful to correlate structure–property relationships of nanodevices on which transmission electron microscopy measurements cannot be typically performed

Additional file 1: of Microwave Hydrothermal Synthesis of Terbium Ions Complexed with Porous Graphene for Effective Absorbent for Organic Dye

Microwave hydrothermal synthesis of terbium ions complexed with porous graphene for effective absorbent for organic dye. (DOCX 2650 kb

Fluid Catalytic Cracking Study of Coker Gas Oil: Effects of Processing Parameters on Sulfur and Nitrogen Distributions

To investigate the effects of operating conditions and the catalyst activity on the transfer regularity of sulfur and nitrogen during the cracking process of coker gas oil (CGO), the CGO was catalytically cracked in a pilot-scale riser fluid catalytic cracking (FCC) apparatus at different test environments. Then the cracked liquid products were analyzed for sulfur and nitrogen distributions with boiling point, from which the sulfur and nitrogen concentrations of gasoline, light cycle oil (LCO), and heavy cycle oil (HCO) fractions were determined. The sulfur and nitrogen compounds in each product cut, and their possible reaction pathways were reviewed and discussed. The results show that sulfur-containing species are easier to crack but more difficult to be removed from the liquid product, while nitrogen compounds are easier to form coke, then be removed from the liquid product. The sulfur distribution of CGO is different from that of conventional feedstocks. Different processing parameters can significantly affect the sulfur and nitrogen distribution yields and concentrations in liquid products. Increasing the reaction temperature and the catalyst-to-oil ratio as well as shortening the residence time cannot only increase the light oil yield but also improve the product quality and reduce the SO_<i>x</i> and NO_<i>x</i> emissions in the regenerator

Investigation of the Mechanisms of Palladium-Catalyzed C–H Acetoxylation and Methoxylation by Electrospray Ionization Mass Spectrometry

Electrospray ionization mass spectrometry (ESI-MS) was used to monitor the progress of the Pd-catalyzed acetoxylation and methoxylation of carbon–hydrogen bonds with PhI­(OAc)₂ as an oxidant. The reaction intermediates were characterized by high-resolution ESI-MS. The reaction mechanisms are proposed to be Pd­(II)–Pd­(IV) or Pd­(II)–Pd­(III) redox cycles depending on the σ-donor ligand and the solvent polarity

MOESM1 of Engineering Corynebacterium glutamicum to produce 5-aminolevulinic acid from glucose

Additional file 1. Figure S1. Multiple-sequence alignment of GluRS (A), HemA (B), and HemL (C) from E. coli and C. glutamicum. Table S1. Strains and plasmids used in this study. Table S2. Primers used in this study. Table S3. Down-regulated genes (-) and up-regulated genes (+) were identified using comparative transcriptome analysis of the C. glutamicum strains SEAL and PECX

Comparison and optimization of CRISPR/dCas9/gRNA genome labeling systems for live cell imaging Additional file 1

Comparison and optimization of CRISPR/dCas9/gRNA genome labeling systems for live cell imaging Additional file

Nanotwin Detection and Domain Polarity Determination via Optical Second Harmonic Generation Polarimetry

We demonstrate that optical second harmonic generation (SHG) can be utilized to determine the exact nature of nanotwins in noncentrosymmetric crystals, which is challenging to resolve via conventional transmission electron or scanned probe microscopies. Using single-crystalline nanotwinned CdTe nanobelts and nanowires as a model system, we show that SHG polarimetry can distinguish between upright (Cd–Te bonds) and inverted (Cd–Cd or Te–Te bonds) twin boundaries in the system. Inverted twin boundaries are generally not reported in nanowires due to the lack of techniques and complexity associated with the study of the nature of such defects. Precise characterization of the nature of defects in nanocrystals is required for deeper understanding of their growth and physical properties to enable their application in future devices

Additional file 1: of Microwave Hydrothermal Synthesis of Terbium Ions Complexed with Porous Graphene for Effective Absorbent for Organic Dye

Microwave hydrothermal synthesis of terbium ions complexed with porous graphene for effective absorbent for organic dye. (DOCX 2650 kb

Synergistic Process for Coker Gas Oil Catalytic Cracking and Gasoline Reformation

The most critical problem of processing coker gas oil (CGO) is its high nitrogen content, especially the basic nitrogen compounds, which limits its cracking performance in the fluid catalytic cracking (FCC) process. For enhancing the conversion of CGO, three processing schemes were evaluated in a pilot-scale riser FCC unit. Four indexes (thermal cracking index, dehydrogenation index, hydrogen transfer coefficient, and isomerization reaction index) were used to investigate the effects of operating conditions on the reactions of CGO cracking. Results show that the optimal operating conditions for CGO cracking are high reaction temperature and large catalyst-to-oil ratio with a short residence time. Therefore, we proposed a synergistic process by selectively recycling light FCC gasoline (LCG) from the upper position of the riser reactor, which can provide a high-severity reaction zone for CGO cracking and a low-severity reaction zone for gasoline upgrading. To further investigate the mutual effect of the two feeds, different recycle ratios of LCG were tested. Results indicate that the conversion of CGO significantly increased with the LCG recycle ratio. When the recycle ratio reached 50 wt %, the gasoline could be upgraded at a higher efficiency. To ensure the optimal recycle ratio and improve the gasoline quality, a two-stage synergistic (TSS) process was proposed. The simulated experiments of the TSS process show that the higher conversion and more desired products can be achieved, even though under a high processing ratio of CGO to conventional feeds

Anti-Epstein–Barr virus antibodies in Beijing during 2013–2017: What we have found in the different patients

<div><p>Background</p><p>Epstein<b>–</b>Barr virus (EBV) is associated with nasopharyngeal carcinoma (NPC) which is prevalent in South China, and its association with systemic lupus erythematosus (SLE) or other autoimmune diseases has not been studied in the mainland of China. The EBV serological tests have been performed on patients with various diseases or manifestations for years at our institution and their values need to be evaluated.</p><p>Methods</p><p>For routine medical purposes, anti-EB viral capsid antigen (VCA) IgG, IgA and IgM antibodies, anti-EBV diffuse early antigen (EA-D) IgA antibodies, and anti-EBV nuclear antigen-1(EBNA-1) IgG antibodies were tested with commercial enzyme-linked immunosorbent assay (ELISA) in patients visiting Peking Union Medical College Hospital between 2013 and 2017. The test results were analyzed in this retrospective study.</p><p>Results</p><p>There were a total of 11122 serum samples available to be tested in the study. As indicators of past EBV infection, the prevalence of VCA-IgG/EBNA1-IgG were 66.6%/58.5%, 84.3%/78.8%, 92.9%/87.0% and 98.5%/95.4% in patients aged under 5 years, 6<b>–</b>10 years, 11<b>–</b>20 years and 21<b>–</b>30 years old, respectively, and these values maintained at this highest rate as age increased further. The prevalence of VCA-IgM, as a parameter of acute EBV infection, was 14.6%, 10.2%, 10.4%, 6.3% and 3.1% in patients aged under 5 years, 6<b>–</b>10 years,11<b>–</b>20 years, 21<b>–</b>30 years, 31<b>–</b>40 years old, respectively, and decreased to 2%~3% in older patients. Patients with elevated serum liver enzymes were more likely to have a higher prevalence of EA/D IgA antibody (<i>P</i> < 0.01) and young patients (≤30 years) with lymphadenopathy were more likely to have higher prevalence of VCA-IgM antibody (<i>P</i> < 0.01). The prevalence of VCA-IgA and EAD-IgA were 87.0% and 59.2% in NPC patients, respectively, and both were significantly higher (<i>P</i> < 0.001) than that in non-NPC patients. The prevalence of VCA-IgA was 45.4% and 25.6% in SLE patients and patients with other autoimmune diseases, respectively, which were significantly (<i>P</i> < 0.001) and mildly (<i>P</i> = 0.039) higher than their controls. In pediatric SLE patients between 6 and10 years old, the prevalence of VCA-IgG, VCA-IgA and EBNA1-IgG was 100%, 59.5% and 100%, respectively, all being significantly higher than the age (6-10y) related controls (<i>P</i>< 0.01). In the 705 cerebral spinal fluid (CSF) specimens, VCA-IgG, VCA-IgM, VCA-IgA and EAD-IgA were found to be positive in 12.1%, 0.15%, 0.25% and 0.25%, respectively. There were 157 paired specimens (CSF and serum were collected simultaneously) and VCA-IgG was identified as positive in 12.7% of the CSF and 100% of the serum specimens.</p><p>Conclusions</p><p>Around 98% of Chinese patients were infected with EBV before 30 years of age and the highest rate of acute EBV infection were observed in patients under 5 years old. EBV infection was found to be associated with elevated serum liver enzymes, NPC and SLE. Acute anti-EBV antibody was valued for young patients with lymphadenopathy but limited value for CNS neuropathy.</p></div