Spin-exciton interaction and related micro-photoluminescence spectra of ZnSe:Mn DMS nanoribbon.

For their spintronic applications the magnetic and optical properties of diluted magnetic semiconductors (DMS) have been studied widely. However, the exact relationships between the magnetic interactions and optical emission behaviors in DMS are not well understood yet due to their complicated microstructural and compositional characters from different growth and preparation techniques. Manganese (Mn) doped ZnSe nanoribbons with high quality were obtained by using the chemical vapor deposition (CVD) method. Successful Mn ion doping in a single ZnSe nanoribbon was identified by elemental energy-dispersive x-ray spectroscopy mapping and micro-photoluminescence (PL) mapping of intrinsic d-d optical transition at 580 nm, i.e. the transition of 4 T 1(4 G) â†’ 6 A 1(6 s),. Besides the d-d transition PL peak at 580 nm, two other PL peaks related to Mn ion aggregates in the ZnSe lattice were detected at 664 nm and 530 nm, which were assigned to the d-d transitions from the Mn2+-Mn2+ pairs with ferromagnetic (FM) coupling and antiferromagnetic (AFM) coupling, respectively. Moreover, AFM pair formation goes along with strong coupling with acoustic phonon or structural defects. These arguments were supported by temperature-dependent PL spectra, power-dependent PL lifetimes, and first-principle calculations. Due to the ferromagnetic pair existence, an exciton magnetic polaron (EMP) is formed and emits at 460 nm. Defect existence favors the AFM pair, which also can account for its giant enhancement of spin-orbital coupling and the spin Hall effect observed in PRL 97, 126603(2006) and PRL 96, 196404(2006). These emission results of DMS reflect their relation to local sp-d hybridization, spin-spin magnetic coupling, exciton-spin or phonon interactions covering structural relaxations. This kind of material can be used to study the exciton-spin interaction and may find applications in spin-related photonic devices besides spintronics.

[A Fast Method to Measure TAN and TBN of Used Lubricant Oil Based on Portable Infrared Spectrometer].

TAN and TBN which provide information about the degree of lubricating oil oxidation and the properties of alkali reserve is usually used in measurement of aging degree of lubricant, and its value can determine whether the amount of certain acid additives added is enough. It can avoid the problems such as, the abnormal wearing, corruption, deposit, filter blocking. The TAN and TBN of Lubricating oil is measured by the standard based on acid-base titration, in which potentiometric titration is used more. However it has to face the problems of complicated operation, expensive consuming material, and large quantity of sample oil, well trained operator and difficulty in handling reagent. Due to the oxidation of lubricating oil products and alkaline additives in the infrared spectrum has strong structural information, therefore, the TAN and TBN of lubricating oil can be monitored by infrared spectra. The quantification of TAN and TBN based on neutralization reaction was built up through the measurement of portable infrared spectroscopy. The reliable quantification of TAN and TBN can be archived by three procedures of lubricant type classification, building up lubricant library and multi-parameters regression. This method is supported by recent ASTM D7889 standard. Compared with the other standard, this method has a high speed of analysis, and it can read out measurement result directly without any solvent. The accuracy of measurement is relatively high, operation is relatively simple, and improve the detection speed at a certain degree. The method can be used widely in industry field, including in laboratory offline measurement and in situ online measurement.

Colloidal Synthesis of CH3 NH3 PbBr3 Nanoplatelets with Polarized Emission through Self-Organization.

We report a combined experimental and theoretical study of the synthesis of CH3 NH3 PbBr3 nanoplatelets through self-organization. Shape transformation from spherical nanodots to square or rectangular nanoplatelets can be achieved by keeping the preformed colloidal nanocrystals at a high concentration (3.5 mg mL-1 ) for 3 days, or combining the synthesis of nanodots with self-organization. The average thickness of the resulting CH3 NH3 PbBr3 nanoplatelets is similar to the size of the original nanoparticles, and we also noticed several nanoplatelets with circular or square holes, suggesting that the shape transformation experienced a self-organization process through dipole-dipole interactions along with a realignment of dipolar vectors. Additionally, the CH3 NH3 PbBr3 nanoplatelets exhibit excellent polarized emissions for stretched CH3 NH3 PbBr3 nanoplatelets embedded in a polymer composite film, showing advantageous photoluminescence properties for display backlights.

Ray-trace simulation of CuInS(Se)2 quantum dot based luminescent solar concentrators.

To enhance the performance of luminescent solar concentrator (LSC), there is an increased need to search novel emissive materials with broad absorption and large Stokes shifts. I-III-VI colloidal CuInS2 and CuInSe2 based nanocrystals, which exhibit strong photoluminescence emissions in the visible to near infrared region with large Stokes shifts, are expected to improve performance in luminescent solar concentrator applications. In this work, the performance of CuInS(Se)2 quantum dots in simple planar LSC is evaluated by applying Monte-Carlo ray-trace simulation. A systematic parameters study was conducted to optimize the performance. An optimized photon concentration ratio of 0.34 for CuInS2 nanocrystals and 1.25 for CuInSe2 nanocrystals doping LSC are obtained from the simulation. The results demonstrated that CuInSe2 based nanocrystals are particularly interesting for luminescent solar concentrator applications, especially to combine with low price Si solar cells.

Synthesis of Novel Sea-Urchin-Like CdS and Their Optical Properties.

A novel morphology of CdS sea-urchin-like microstructures is synthesized by simple thermal evaporation process. Microstructures with average size of 20-50 µm are composed of single crystalline CdS nanobelts. The structural, compositional, morphological characterization of the product were examined by X-ray diffraction, energy dispersive X-ray spectroscopy, Raman spectroscopy, scanning electron microscope, transmission electron microscopy and selected area electron diffraction while optical properties are investigated by Photoluminescence spectroscopy and time-resolved Photoluminescence measurements. The tentative growth mechanism for the growth of sea-urchin-like CdS is proposed and described briefly. A strong green emission with a maximum around 517 nm was observed from the individual CdS microstructure at room temperature, which was attributed to band-edge emission of CdS. These Novel structures exhibit excellent lasing (stimulated emission) with low threshold (9.07 µJ cm(-2)) at room temperature. We analyze the physical mechanism of stimulated emission. These results are important in the design of green luminescence, low-threshold laser and display devices in the future.

Prohibitin Interacts with envelope proteins of white spot syndrome virus and prevents infection in the red swamp crayfish, Procambarus clarkii.

Prohibitins (PHBs) are ubiquitously expressed conserved proteins in eukaryotes that are associated with apoptosis, cancer formation, aging, stress responses, cell proliferation, and immune regulation. However, the function of PHBs in crustacean immunity remains largely unknown. In the present study, we identified a PHB in Procambarus clarkii red swamp crayfish, which was designated PcPHB1. PcPHB1 was widely distributed in several tissues, and its expression was significantly upregulated by white spot syndrome virus (WSSV) challenge at the mRNA level and the protein level. These observations prompted us to investigate the role of PcPHB1 in the crayfish antiviral response. Recombinant PcPHB1 (rPcPHB1) significantly reduced the amount of WSSV in crayfish and the mortality of WSSV-infected crayfish. The quantity of WSSV in PcPHB1 knockdown crayfish was increased compared with that in the controls. The effects of RNA silencing were rescued by rPcPHB1 reinjection. We further confirmed the interaction of PcPHB1 with the WSSV envelope proteins VP28, VP26, and VP24 using pulldown and far-Western overlay assays. Finally, we observed that the colloidal gold-labeled PcPHB1 was located on the outer surface of the WSSV, which suggests that PcPHB1 specifically binds to the envelope proteins of WSSV. VP28, VP26, and VP24 are structural envelope proteins and are essential for attachment and entry into crayfish cells. Therefore, PcPHB1 exerts its anti-WSSV effect by binding to VP28, VP26, and VP24, preventing viral infection. This study is the first report on the antiviral function of PHB in the innate immune system of crustaceans.

Tunable emission properties by ferromagnetic coupling Mn(II) aggregates in Mn-doped CdS microbelts/nanowires.

Tunable optical emission properties from ferromagnetic semiconductors have not been well identified yet. In this work, high-quality Mn(II)-doped CdS nanowires and micrometer belts were prepared using a controlled chemical vapor deposition technique. The Mn doping could be controlled with time, precursor concentration and temperature. These wires or belts can produce both tunable redshifted emissions and ferromagnetic responses simultaneously upon doping. The strong emission bands at 572, 651, 693, 712, 745, 768, 787 and 803 nm, due to the Mn(II) (4)T1((4)G)  → (6)A1((6)s) d-d transition, can be detected and accounted for by the aggregation of Mn ions at Cd sites in the CdS lattice at high temperature. These aggregates with ferromagnetism and shifted luminescence are related to the excitonic magnetic polaron (EMP) and localized EMP formations; this is verified by ab initio calculations. The correlation between aggregation-dependent optical emissions and ferromagnetic responses not only presents a new size effect for diluted magnetic semiconductors (DMSs), but also supplies a possible way to study or modulate the ferromagnetic properties of a DMS and to fabricate spin-related photonic devices in the future.

Involvement of Fenneropenaeus chinensis Cathepsin C in antiviral immunity.

Cathepsin C (Cath C) is a lysosomal cysteine protease that belongs to the papain superfamily. Cath C is capable of activating many chymotrypsin-like serine proteases and is reported to be a central coordinator for the activation of many serine proteinases in immune and inflammatory cells. In this study, Cath C cDNA was cloned from Fenneropenaeus chinensis (Fc). The complete cDNA of Fc-Cath C in Chinese white shrimp was found to be 1445-base pairs (bp) long. It contained an open reading frame (ORF) 1356-bp long and encoded a 451-amino acid residue protein, including a 17-amino acid residue signal peptide. Real-time PCR analysis results indicated that Fc-Cath C was present in all the tissues detected and exhibited high level of transcription in the hepatopancreas. In hemocytes, hepatopancreas, gills and intestine, Fc-Cath C was upregulated after stimulation by the Vibrio anguillarum and the white spot syndrome viruses (WSSVs). Replication of the WSSV increased after the injection of Fc-Cath C antiserum or knockdown Cath C by RNA interference. These results implied that Cath C might play a crucial role in the antiviral immune response of shrimp.

Electric field controlled type-I and type-II conversion of BP/SnS van der Waals heterostructure.

Type-I heterostructure, in which electrons and holes are confined in same region, is widely used in light emitting diodes and semiconductor lasers. Type-II heterostructure is widely used in photovoltaic devices because of its excellent spatial separation property of electrons and holes. Can we integrate photovoltaic, photoelectric properties with luminescent property in one device? Here we report a van der Waals heterostructure formed by black phosphorus (BP) and SnS monolayers. It is expected to realize these functions in one device. By first-principles methods, the structural stability, electronic properties and optical properties are investigated. It was found that the BP/SnS bilayer is type-II heterostructure with an indirect bandgap of 0.56 eV. Thep-like character of the band edge in BP/SnS vdW heterostructure makes it to be an excellent optoelectronic material. The type-II stability of the system can be improved by applying a negative electric field. However, when the positive electric field is bigger than 0.1 V Å-1, the system begins to transform from type-II to type I. Therefore, by adding a gate voltage the bandgap and band alignment of this system can be controlled. The photovoltaic and photoelectric properties can be integrated in one device based on this heterostructure.

Widely tunable direct bandgap of two-dimensional GeSe.

Bulk GeSe is an indirect bandgap semiconductor. However, direct bandgap semiconductor of two-dimensional GeSe can be obtained by applying strain along armchair direction, and the direct bandgap can be tuned in a wide energy range from 0.86 eV to 0.00 eV by electric field. The bandgap modulation mechanism is studied in detail by first-principle calculations. The calculations of phonon spectra show that the crystal structure is relatively stable under the strain and electric field. Therefore, 2D GeSe is a promising material in frequency adjustable electronic and optical devices.

Whether Syndrome Differentiation Affects Treatment Result: Study Protocol of MaZiRenWan () for Functional Constipation in A Randomized Controlled Trial.

BACKGROUND: Syndrome is one of the most important concepts in Chinese medicine (CM) theory. However, it was not well accounted in most of randomized controlled trials (RCTs). OBJECTIVES: To determine whether CM syndrome differentiation affects the treatment results, functional constipation (FC) was selected as a target disease, and MaZiRenWan (, MZRW), a classic CM formula commonly used for constipation with excessive heat syndrome, was selected for study. METHODS: It is an 18-week prospective double-blinded, doubledummy RCT, including 2-week run-in, 8-week treatment and 8-week post treatment follow-up. A total of 120 FC patients diagnosed as excessive heat syndrome will be recruited from the First Teaching Hospital of Tianjin University of Traditional Chinese Medicine and the Baokang Affiliated Hospital of Tianjin University of Traditional Chinese Medicine. Patients will be randomly allocated into fixed MZRW (f_MZRW) granule group, modified MZRW (m_MZRW) granule group or bisacodyl group. For m_MZRW group, no more than two herbal granules can be added according to the syndrome differentiation for individual participants. The primary end point is the mean of complete spontaneous bowel movements (CSBMs) per week during the treatment period. Secondary end points include mean of CSBMs per week during follow-up, stool form, global symptom improvement, constipation and constipation-related symptoms assessment, CM syndrome change, and reported adverse events. DISCUSSION: This trial is designed to evaluate the effectiveness of these three interventions for FC patients with the CM syndrome of excessive heat, and to determine the change of CM syndrome and the progress of disease during the treatment course. The results are important to explore whether syndrome differentiation is important for the therapeutic effect of a formula on a disease. [Trial registration: Chinese Clinical Trial Registry (Reg No. ChiCTR-TRC-13003742); protocol version: MZRW/NSFC-81173363 (2015.05.04)].

The tunable bandgap effect of SnS films.

Two-dimensional (2D) SnS has attracted much attention as a phosphorene analogue due to the promising applications in next-generation nanoelectronic and photovoltaic devices. It has a bandgap of 1.3 eV, which is matched very well with incident solar radiation. To improve the switching character of devices, it is significant to modulate the bandgap of 2D SnS. In this work, potassium ion (K+) or calcium ion (Ca2+) is absorbed on the top surface of SnS films to produce an electric field, by which the bandgap can be tuned effectively. By first-principles method we studied the electronic properties and the modulation mechanism of bandgap in detail. The calculated ionization energy and formation energy are 0.41 eV and 0.26 eV for K (1.33 eV and 1.07 eV for Ca). Such little values indicate that it is feasible for ion absorbed on the surface to be used to modulate the bandgap of SnS films. Our calculations also show that the carrier mobility in plane of SnS films has a character of strong anisotropy and the electron mobility is very high in y direction (25.22 × 103 cm2 V-1 s-1 for SnS trilayer). Therefore 2D SnS has potential application in nanoelectronic and photovoltaic devices in the future. We hope our results will motivate experimental efforts of 2D SnS.

ß-Thymosins participate in antiviral immunity of red swamp crayfish (Procambarus clarkii).

ß-Thymosins participate in numerous biological activities, including cell proliferation and differentiation, wound healing, and anti-inflammatory and antimicrobial activities. Many studies have investigated vertebrate ß-thymosins, whereas few reports have focused on invertebrate ß-thymosins. In this study, nine isoforms of ß-thymosins (PcThy-1 to PcThy-8) were identified from the red swamp crayfish Procambarus clarkii. The isoforms contained different numbers of the thymosin ß actin-binding motif. PcThy-1 contained one thymosin ß actin-binding motif, whereas PcThy-8 contained eight motifs. Western blot analysis with anti-PcThy-4 antibody showed that three to six isoforms were present in one tissue, and PcThy-4, PcThy-5, PcThy-6, and PcThy-7 were the main isoforms in several tissues. Time course expression analysis of PcThys at the protein level showed that PcThy-4 was upregulated in hemocytes and gills after white spot syndrome virus (WSSV) challenge. PcThy-4, which contained four thymosin ß actin-binding motifs, was selected for further research. Tissue distribution analysis by quantitative real-time PCR showed that PcThy-4 was present in tissues of the hemocytes, heart, hepatopancreas, gills, stomach, and intestine at the transcriptional level. Transcriptional expression profiles showed that PcThy-4 was upregulated after WSSV challenge. In vivo RNAi and protein injection assay results showed that PcThy-4 inhibited the replication of WSSV in crayfish and enhanced the survival rate after WSSV infection. Furthermore, PcThy-4 promoted hemocyte phagocytosis of WSSV. Overall, results suggested that PcThys protected crayfish from WSSV infection and played an important role in antiviral immune response.

TRBP and eIF6 homologue in Marsupenaeus japonicus play crucial roles in antiviral response.

Plants and invertebrates can suppress viral infection through RNA silencing, mediated by RNA-induced silencing complex (RISC). Trans-activation response RNA-binding protein (TRBP), consisting of three double-stranded RNA-binding domains, is a component of the RISC. In our previous paper, a TRBP homologue in Fenneropenaeus chinensis (Fc-TRBP) was reported to directly bind to eukaryotic initiation factor 6 (Fc-eIF6). In this study, we further characterized the function of TRBP and the involvement of TRBP and eIF6 in antiviral RNA interference (RNAi) pathway of shrimp. The double-stranded RNA binding domains (dsRBDs) B and C of the TRBP from Marsupenaeus japonicus (Mj-TRBP) were found to mediate the interaction of TRBP and eIF6. Gel-shift assays revealed that the N-terminal of Mj-TRBP dsRBD strongly binds to double-stranded RNA (dsRNA) and that the homodimer of the TRBP mediated by the C-terminal dsRBD increases the affinity to dsRNA. RNAi against either Mj-TRBP or Mj-eIF6 impairs the dsRNA-induced sequence-specific RNAi pathway and facilitates the proliferation of white spot syndrome virus (WSSV). These results further proved the important roles of TRBP and eIF6 in the antiviral response of shrimp.