Electromagnetically Induced Transparency in the Strongly Relativistic Regime.

Stable transport of laser beams in highly overdense plasmas is of significance in the fast ignition of inertial confinement fusion, relativistic electron generation, and powerful electromagnetic emission, but hard to realize. Early in 1996, Harris proposed an electromagnetically induced transparency (EIT) mechanism, analogous to the concept in atomic physics, to transport a low-frequency (LF) laser in overdense plasmas aided by a high-frequency pump laser. However, subsequent investigations show that EIT cannot occur in real plasmas with boundaries. Here, our particle-in-cell simulations show that EIT can occur in the strongly relativistic regime and result in stable propagation of a LF laser in bounded plasmas with tens of its critical density. A relativistic three-wave coupling model is developed, and the criteria and frequency passband for EIT occurrence are presented. The passband is sufficiently wide in the strongly relativistic regime, allowing EIT to work sustainably. Nevertheless, it is narrowed to nearly an isolated point in the weakly relativistic regime, which can explain the quenching of EIT in bounded plasmas found in previous investigations.

Dense Polarized Positrons from Beam-Solid Interaction.

Relativistic positron sources with high spin polarization have important applications in nuclear and particle physics and many frontier fields. However, it is challenging to produce dense polarized positrons. Here we present a simple and effective method to achieve such a positron source by directly impinging a relativistic high-density electron beam on the surface of a solid target. During the interaction, a strong return current of plasma electrons is induced and subsequently asymmetric quasistatic magnetic fields as high as megatesla are generated along the target surface. This gives rise to strong radiative spin flips and multiphoton processes, thus leading to efficient generation of copious polarized positrons. With three-dimensional particle-in-cell simulations, we demonstrate the production of a dense highly polarized multi-GeV positron beam with an average spin polarization above 40% and nC-scale charge per shot. This offers a novel route for the studies of laserless strong-field quantum electrodynamics physics and for the development of high-energy polarized positron sources.

Highly sensitive detection of broadband terahertz waves using aqueous salt solutions.

Water-based coherent detection of broadband terahertz (THz) wave has been recently proposed with superior performances, which can alleviate the limited detection bandwidth and high probe laser energy requirement in the solid- and air-based detection schemes, respectively. Here, we demonstrate that the water-based detection method can be extended to the aqueous salt solutions and the sensitivity can be significantly enhanced. The THz coherent detection signal intensity scales linearly with the third-order nonlinear susceptibility χ(3) or quadratically with the linear refractive index η0 of the aqueous salt solutions, while the incoherent detection signal intensity scales quadratically with χ(3) or quartically with η0, proving the underlying mechanism is the four-wave mixing. Both the coherent and incoherent detection signal intensities appear positive correlation with the solution concentration. These results imply that the liquid-based THz detection scheme could provide a new technique to measure χ(3) and further investigate the physicochemical properties in the THz band for various liquids.

Dense Polarized Positrons from Laser-Irradiated Foil Targets in the QED Regime.

Many works have shown that dense positrons can be effectively generated from laser-solid interactions in the strong-field quantum electrodynamics (QED) regime. Whether these positrons are polarized has not yet been reported, limiting their potential applications. Here, by polarized QED particle-in-cell simulations including electron-positron spin and photon polarization effects, we investigate a typical laser-solid setup that an ultraintense linearly polarized laser irradiates a foil target with micrometer-scale-length preplasmas. We find that once the positron yield becomes appreciable with the laser intensity exceeding 10^{24} W/cm^{2}, the positrons are obviously polarized. Around 30 nC positrons can acquire >30% polarization degree with a flux of 10^{12} sr^{-1}. The angle-dependent polarization is attributed to the asymmetrical laser fields that positrons undergo near the skin layer of overdense plasmas, where radiative spin flip and radiation reaction play significant roles. The polarization mechanism is robust and could generally appear in future 100-PW-class laser-solid experiments.

Water-Based Coherent Detection of Broadband Terahertz Pulses.

Both solids and gases have been demonstrated as the materials for terahertz (THz) coherent detection. The gas-based coherent detection methods require a high-energy probe laser beam and the detection bandwidth is limited in the solid-based methods. Whether liquids can be used for THz detection and relax these problems has not yet been reported, which becomes a timely and interesting topic due to the recent observation of efficient THz wave generation in liquids. Here, we propose a THz coherent detection scheme based on liquid water. When a THz pulse and a fundamental laser beam are mixed on a free-flowing water film, a second harmonic (SH) beam is generated as the plasma is formed. Combining this THz-induced SH beam with a control SH beam, we successfully achieve the time-resolved waveform of the THz field with the frequency range of 0.1-18 THz. The required probe laser energy is as low as a few microjoules. The sensitivity of our scheme is 1 order of magnitude higher than that of the air-based method under comparable detection conditions. The scheme is sensitive to the THz polarization and the phase difference between the fundamental and control SH beams, which brings direct routes for optimization and polarization sensitive detection. Energy scaling and polarization properties of the THz-induced beam indicate that its generation can be attributed to a four-wave mixing process. This generation mechanism makes simple relationships among the probe laser, THz-induced SH, and THz field, favorable for robustness and flexibility of the detection device.

White thrombi on optical coherence tomography after rotational atherectomy of severely calcified coronary lesions.

PURPOSE: Rotational atherectomy (RA) has improved percutaneous treatment of severely calcified coronary lesions, but the "no-reflow" phenomenon remains a serious complication. Platelet activation by RA may contribute to no-reflow, and the use of optical coherence tomography (OCT) to test the effect of RA on white thrombus could confirm platelet activation indirectly. METHODS: We analyzed 53 consecutive patients with severely calcified lesions on coronary angiography. All patients were examined with OCT. In total, 20 patients who received RA and for whom OCT imaging was performed before and after RA and stent implantation comprised the RA group. The remaining 33 patients formed the control group, for whom OCT imaging was performed before balloon dilatation and after stent implantation. RESULTS: The patients in the RA group were older and had a higher incidence of diabetes mellitus. In the control group, there was no thrombogenesis during the procedure, whereas in the RA group, all the target vessels had white thrombi on OCT after RA. The average number of white thrombi per lesion after RA was 7.23 ± 4.4, and the average length of white thrombus was 0.51 ± 0.33 mm. Statistical analysis with Pearson's correlation coefficient showed that thrombus load was related to burr size (r = 0.575, p = 0.040) and number of rotations (r = 0.599, p = 0.031). CONCLUSION: White thrombi during RA can be verified by performing OCT. Treating calcified lesions with RA may enhance thrombogenesis. These data suggest using appropriate therapy to avoid no-reflow during RA.

Assessing the effect of probiotics on tilapia lake virus-infected tilapia: Transmission and immune response.

Probiotics have been used to alleviate disease transmission in aquaculture. However, there are limited studies on probiotic use in modulating tilapia lake virus (TiLV). We assessed commercially available probiotic supplements used in TiLV-infected tilapia and performed mortality and cohabitation assays. We developed a mechanistic approach to predict dose-response interactions of probiotic effects on mortality and immune gene response. We used a susceptible-infected-mortality disease model to assess key epidemiological parameters such as transmission rate and basic reproduction number (R0 ) based on our viral load dynamic data. We found that the most marked benefits of probiotics are significantly associated with immune system enhancements (~30%) and reductions in disease transmission (~80%) and R0 (~70%) in tilapia populations, resulting in a higher tolerance of farming densities (~400 fold) in aquaculture. These findings provide early insights as to how probiotic use-related factors may influence TiLV transmission and the immune responses in TiLV-infected tilapia. Our study facilitates understanding the mode of action of probiotics in disease containment and predicting better probiotic dosages in diet and supplements to achieve the optimal culturing conditions. Overall, our analysis assures that further study of rationally designed and targeted probiotics, or mechanistic modelling is warranted on the basis of promising early data of this approach.

Epirubicin-induced Kounis syndrome.

BACKGROUND: Kounis syndrome is an acute coronary syndrome that appears in the setting of anaphylactic reaction or hypersensitivity. Many drugs and environmental exposures have been identified as potential offenders, and diagnosis and treatment can be challenging. CASE PRESENTATION: A 62-year-old man with recurrent bladder cancer underwent an intra-iliac artery epirubicin injection. After the injection, he developed chest pain and a systemic allergic reaction, with electrocardiographic alterations and elevated troponin-I levels. Emergent coronary angiography showed right coronary artery spasm and no stenosis of the other coronary arteries. This reaction was considered compatible with an allergic coronary vasospasm. A diagnosis of Kounis syndrome was made. CONCLUSIONS: Kounis syndrome is common, but a prompt diagnosis is often not possible. This case is the first to suggest that an intraarterial epirubicin injection could potentially be one of its triggers. All physicians should be aware of the pathophysiology of this condition to better recognize it and start appropriate treatment; this will prevent aggravation of the vasospastic cardiac attacks and yield a better outcome.

Collimated ultrabright gamma rays from electron wiggling along a petawatt laser-irradiated wire in the QED regime.

Even though high-quality X- and gamma rays with photon energy below mega-electron volt (MeV) are available from large-scale X-ray free electron lasers and synchrotron radiation facilities, it remains a great challenge to generate bright gamma rays over 10 MeV. Recently, gamma rays with energies up to the MeV level were observed in Compton scattering experiments based on laser wakefield accelerators, but the yield efficiency was as low as [Formula: see text], owing to low charge of the electron beam. Here, we propose a scheme to efficiently generate gamma rays of hundreds of MeV from submicrometer wires irradiated by petawatt lasers, where electron accelerating and wiggling are achieved simultaneously. The wiggling is caused by the quasistatic electric and magnetic fields induced around the wire surface, and these are so high that even quantum electrodynamics (QED) effects become significant for gamma-ray generation, although the driving lasers are only at the petawatt level. Our full 3D simulations show that directional, ultrabright gamma rays are generated, containing [Formula: see text] photons between 5 and 500 MeV within a 10-fs duration. The brilliance, up to [Formula: see text] photons [Formula: see text] per 0.1% bandwidth at an average photon energy of 20 MeV, is second only to X-ray free electron lasers, while the photon energy is 3 orders of magnitude higher than the latter. In addition, the gamma ray yield efficiency approaches 10%-that is, 5 orders of magnitude higher than the Compton scattering based on laser wakefield accelerators. Such high-energy, ultrabright, femtosecond-duration gamma rays may find applications in nuclear photonics, radiotherapy, and laboratory astrophysics.

Production of Highly Polarized Positron Beams via Helicity Transfer from Polarized Electrons in a Strong Laser Field.

The production of a highly polarized positron beam via nonlinear Breit-Wheeler processes during the interaction of an ultraintense circularly polarized laser pulse with a longitudinally spin-polarized ultrarelativistic electron beam is investigated theoretically. A new Monte Carlo method employing fully spin-resolved quantum probabilities is developed under the local constant field approximation to include three-dimensional polarization effects in strong laser fields. The produced positrons are longitudinally polarized through polarization transferred from the polarized electrons by the medium of high-energy photons. The polarization transfer efficiency can approach 100% for the energetic positrons moving at smaller deflection angles. This method simplifies the postselection procedure to generate high-quality positron beams in further applications. In a feasible scenario, a highly polarized (40%-65%), intense (10^{5}-10^{6}/bunch), collimated (5-70 mrad) positron beam can be obtained in a femtosecond timescale. The longitudinally polarized positron sources are desirable for applications in high-energy physics and material science.

Comparison of bailout and planned rotational atherectomy for severe coronary calcified lesions.

BACKGROUND: To compare outcomes of bailout and planned rotational atherectomy (RA) in the treatment of severe calcified coronary lesions. METHODS: Data of patients treated with RA from 2017 to 2018 at a single-center registry were retrospectively analyzed. All patients were divided into planned RA and bailout RA groups, data between two groups were compared. RESULTS: A total of 190 patients were included in this study, 138 patients received planned RA and 52 patients received bailout RA. Baseline clinical characteristics had no significant differences between groups. The number of implanted stents and total stents length were similar. But the number of balloon (1.6 ± 0.8 vs. 2.7 ± 1.3, P < 0.001), procedure time (83.5 ± 26.2 vs. 100.8 ± 36.4 min, P = 0.007), fluoroscopy volume (941 ± 482 vs. 1227 ± 872 mGy, P = 0.012] and contrast amount (237 ± 62 vs. 275 ± 90 ml, P = 0.003) were all lower in planned RA group. Planned RA had a higher procedural success rate (99.3% vs. 92.3%, P = 0.007) and a lower complication incidence (4.3% vs. 17.3%, P = 0.009). But the primary outcomes at 3 years (9.2 and 16.6%, log rank p = 0.24) had no difference between groups. CONCLUSIONS: For severe coronary artery calcification, although planned RA did not improved the long term prognosis compared with bailout RA, but it can improve the immediate procedural success rate, reduce the incidence of complications, the procedure time and the volume of contrast.

Gene expression patterns indicate that a high-fat-high-carbohydrate diet causes mitochondrial dysfunction in fish.

Expensive and unsustainable fishmeal is increasingly being replaced with cheaper lipids and carbohydrates as sources of energy in aquaculture. Although it is known that the excess of lipids and carbohydrates has negative effects on nutrient utilization, growth, metabolic homeostasis, and health of fish, our current understanding of mechanisms behind these effects is limited. To improve the understanding of diet-induced metabolic disorders (both in fish and other vertebrates), we conducted an eight-week high-fat-high-carbohydrate diet feeding trial on blunt snout bream (Megalobrama amblycephala), and studied gene expression changes (transcriptome and qPCR) in the liver. Disproportionately large numbers of differentially expressed genes were associated with mitochondrial metabolism, neurodegenerative diseases (Alzheimer's, Huntington's, and Parkinson's), and functional categories indicative of liver dysfunction. A high-fat-high-carbohydrate diet may have caused mitochondrial dysfunction, and possibly downregulated the mitochondrial biogenesis in the liver. While the relationship between diet and neurodegenerative disorders is well-established in mammals, this is the first report of this connection in fish. We propose that fishes should be further explored as a potentially promising model to study the mechanisms of diet-associated neurodegenerative disorders in humans.

Identification, characterization and expression in response to Aeromonas hydrophila challenge of five interferon regulatory factors in Megalobrama amblycephala.

Interferon regulatory factor (Irf) family represents one of the most important transcription factor families, with multiple biological roles. In this study, we characterized five Irf family members (irf4a, irf4b, irf6, irf8 and irf10) in Megalobrama amblycephala at the cDNA and (predicted) amino acid levels, analyzed them phylogenetically, and developed gene-specific primers for qPCR analysis. All five irfs were constitutively expressed in all examined tissues, but their transcription was significantly higher in lymphoid organs and tissues, such as kidney, spleen and intestine. Exceptions were irf8, which was expressed at a high level in heart and brain tissues, and irf6, expressed at low levels in most tissues. After a bacterial immune challenge with Aeromonas hydrophila, the expression of irfs in liver was up-regulated: mairf4a 8.12-fold, mairf4b 29.9-fold, mairf6 1.38-fold and mairf10 1.65-fold (mairf8 was an exception: 0.07-fold). In spleen, kidney, intestine and gills, transcript levels of studied irfs increased only at specific time-points. The results suggested that irfs are involved in the immune response to bacterial infection in M. amblycephala, which will help elucidate the biological functions of irfs in the immune system of teleost fish.

Isolation and expression of four Megalobrama amblycephala toll-like receptor genes in response to a bacterial infection.

Toll-like receptors (TLRs) are a category of pattern recognition receptors (PRRs), which recognize pathogen associated molecular patterns (PAMPs) and participate in the immune responses. We identified tlr5a, tlr5b, tlr9 and tlr21 from the genome of blunt snout bream (Megalobrama amblycephala). All four tlrs were constitutively expressed in all examined tissues. After an immune bacterial challenge with Aeromonas hydrophila, their expressionwas up-regulated in lymphoid organs and tissues. Recombinant eukaryotic plasmid pEGFP-N1 was transfected into the common carp (Cyprinus carpio) EPC (epithelioma papulosum cyprini) cells for the purpose of subcellular localization. pcDNA3.1(+) recombinant eukaryotic plasmid was used to investigate the effects of overexpression of tlrs on the expression of downstream interferon-associated immune factors. The four Tlrs were distributed in the cytoplasm of transfected cells and appeared as filamentous or reticular. The expression of irf3, irf7, isg15, mx1, pkr and viperin at 0, 6, 12, 18, 24, 36, 48 and 72 h post-transfection in transfected EPC cells was quantified by qPCR. Overexpression of tlrs upregulated the expression of viperin, isg15, irf3, irf7, mx1 and pkr (in that order of magnitude). We also cloned the following promoters of irfs: Irf1-p, irf2-p, irf6-p, irf7-p, irf8-p and irf9-p. Results of the dual luciferase reporter assay suggested that tlr5a, tlr5b and tlr9 enhanced the activities of irf7-p, while tlr5b enhanced the activities of irf1-p and irf7-p. This suggests that they all play a role in the innate immunity. The experiments also indicated that TLRs activate irf3 or irf7 signaling to induce IFN secretion and subsequent upregulation of IFN-stimulated genes. These results indicate that tlrs and irfs play an important immune role in response to A. hydrophila infection in blunt snout bream, and pave the way for further studies of immune mechanisms mediated by TLRs in fish.

Development of Teleost Intermuscular Bones Undergoing Intramembranous Ossification Based on Histological-Transcriptomic-Proteomic Data.

Intermuscular bones (IBs) specially exist in lower teleost fish and the molecular mechanism for its development remains to be clarified. In this study, different staining methods and comparative proteomics were conducted to investigate the histological structure and proteome of IB development in Megalobrama amblycephala, including four key IB developmental stages (S1-IBs have not emerged in the tail part; S2-several small IBs started to ossify in the tail part; S3-IBs appeared rapidly; S4-all the IBs appeared with mature morphology). Alcian blue and alizarin red S stained results indicated that IBs were gradually formed from S2 to S4, undergoing intramembranous ossification without a cartilaginous phase. A total of 3368 proteins were identified by using the isobaric tags for relative and absolute quantitation (iTRAQ) approach. Functional annotation showed that proteins which were differentially expressed among stages were involved in calcium, MAPK, Wnt, TGF-ß, and osteoclast pathways which played a critical role in bone formation and differentiation. Three proteins (collagen9α1, stat1, tnc) associated with chondrocytes did not exhibit significant changes through S2 to S4; however, proteins (entpd5, casq1a, pvalb, anxa2a, anxa5) which associated with osteoblasts and bone formation and differentiation showed significantly a higher expression level from S1 to S2, as well as to S3 and S4. These further demonstrated that development of IBs did not go through a cartilaginous phase. The inhibitors of TGF-ß and Wnt pathways were tested on zebrafish (sp7/eGFP) and the results indicated that both inhibitors significantly delayed IB development. This study provides a comprehensive understanding of the IB ossification pattern, which will help further elucidate the molecular mechanisms for IB development in teleosts.

Is the Nutritional Value of Fish Fillet Related to Fish Maturation or Fish Age? Integrated Analysis of Transcriptomics and Metabolomics in Blunt Snout Bream (Megalobrama amblycephala).

BACKGROUND/AIMS: Fish is a protein-rich food and is increasingly favored by consumers. It has been well recognized that the flesh composition of fish is closely related to its maturation and growth stage, but few studies have explored these differences. Additionally, hormone residues in fish after artificial induction of reproduction also attract consumer concern. In this study, we attempt to address these concerns by using a combination of transcriptomics and metabolomics analyses to identify key regulated pathways, genes, and metabolites that may affect the flesh nutrition of one typical aquaculture species in China, blunt snout bream (Megalobrama amblycephala). METHODS: The four groups of fish were used for transcriptomics and metabolomics analyses, including one-year-old immature (group I), two-year-old immature (group II), two-year-old mature (group III) and successfully spawned (group IV) female M. amblycephala after artificial induction of reproduction. RESULTS: We identified a total of 1460 differential compounds and 1107 differentially expressed unigenes in muscle among the different groups. Differential metabolites related to fish age (group II vs group I, group III vs group I) were largely enriched in "Glycerophospholipid metabolism", "Linoleic acid metabolism", "α-Linolenic acid metabolism", and "Biosynthesis of unsaturated fatty acids". Between these two pairwise comparisons, metabolites that are beneficial to human health, such as docosapentaenoic acid, α-Linolenic acid, eicosapentaenoic acid, and docosahexaenoic acid were found to be significantly decreased in two-year-old (group II, group III) compared with one-year-old (group I) M. amblycephala. Only one differential metabolite related to fish maturation, a triglyceride, was detected between groups III and II. Transcriptomics data showed that differently expressed genes (between group III vs group II, group III vs group I) related to maturation were highly enriched in "Cell adhesion molecules (CAMs)", "Sphingolipid metabolism" and "Phagosome". DEGs (between group II vs group I, group III vs group I) relating to fish age were enriched in the "cGMP-PKG signaling pathway", "FoxO signaling pathway", and "AMPK signaling pathway". The gene-metabolite interaction network showed pivotal genes, including fumarate hydratase and GNPAT, which played a major role in the regulation of glycerphospholipid metabolism. The nutritional components were also measured, which verified the metabolomics results. Moreover, the metabolomics results showed that after 24 hours of artificial hormone injection, the drug was completely metabolized. CONCLUSION: Integrated analysis demonstrated that the nutrition value of fish fillet was much more related to fish age compared with maturation status in M. amblycephala females.

Metabolite and gene expression profiles suggest a putative mechanism through which high dietary carbohydrates reduce the content of hepatic betaine in Megalobrama amblycephala.

BACKGROUND: High-carbohydrate diets (HCD) are favoured by the aquaculture industry for economic reasons, but they can produce negative impacts on growth and induce hepatic steatosis. We hypothesised that the mechanism behind this is the reduction of hepatic betaine content. OBJECTIVE: We further explored this mechanism by supplementing betaine (1%) to the diet of a farmed fish Megalobrama amblycephala. METHODS: Four diet groups were designed: control (CD, 27.11% carbohydrates), high-carbohydrate (HCD, 36.75% carbohydrates), long-term betaine (LBD, 35.64% carbohydrates) and short-term betaine diet (SBD; 12 weeks HCD + 4 weeks LBD). We analysed growth performance, body composition, liver condition, and expression of genes and profiles of metabolites associated with betaine metabolism. RESULTS: HCD resulted in poorer growth and liver health (compared to CD), whereas LBD improved these parameters (compared to HCD). HCD induced the expression of genes associated with glucose, serine and cystathionine metabolisms, and (non-significantly, p = .20) a betaine-catabolizing enzyme betaine-homocysteine-methyltransferase; and decreased the content of betaine, methionine, S-adenosylhomocysteine and carnitine. Betaine supplementation (LBD) reversed these patterns, and elevated betaine-homocysteine-methyltransferase, S-adenosylmethionine and S-adenosylhomocysteine (all p ≤ .05). CONCLUSION: We hypothesise that HCD reduced the content of hepatic betaine by enhancing the activity of metabolic pathways from glucose to homocysteine, reflected in increased glycolysis, serine metabolism, cystathionine metabolism and homocysteine remethylation. Long-term dietary betaine supplementation improved the negative impacts of HCD, inculding growth parameters, body composition, liver condition, and betaine metabolism. However, betaine supplementation may have caused a temporary disruption in the metabolic homeostasis.

Transcriptomics, metabolomics and histology indicate that high-carbohydrate diet negatively affects the liver health of blunt snout bream (Megalobrama amblycephala).

BACKGROUND: Global trend of the introduction of high levels of relatively cheap carbohydrates to reduce the amount of costly protein in the aquatic animal feed production has affected the aquaculture of an economically important cyprinid fish, blunt snout bream (Megalobrama amblycephala). This dietary shift has resulted in increased prevalence of metabolic disorders, often causing economic losses. High dietary intake of carbohydrates, associated with obesity, is one of the major causes of non-alcoholic fatty liver disease (NAFLD) in humans. RESULTS: We have conducted an eight-week feeding trial to better understand how a high-carbohydrate diet (HCBD) affects the liver health in this fish. Hepatosomatic index and lipid content were significantly (P < 0.05) higher in the HCBD group. Histology results also suggested pathological changes in the livers of HCBD group, with excessive lipid accumulation and indication of liver damage. Metabolomics and serum biochemistry analyses showed that a number of metabolites indicative of liver damage were increased in the HCBD group. This group also exhibited low levels of betaine, which is a metabolite crucial for maintaining the healthy liver functions. Transcriptomic and qPCR analyses indicated that HCBD had a strong impact on the expression of a large number of genes associated with the NAFLD and insulin signalling pathways, which may lead to the development of insulin resistance in hepatocytes, pathological liver changes, and eventually the NAFLD. CONCLUSIONS: Transcriptomics, metabolomics and histology results all indicate early symptoms of liver damage. However whether these would actually lead to the development of NAFLD after a longer period of time, remains inconclusive. Additionally, a very high number of upregulated genes in the HCBD group associated with several neurodegenerative diseases is a strong indication of neurodegenerative changes caused by the high-carbohydrate diet in blunt snout bream. This suggests that fish might present a good model to study neurodegenerative changes associated with high-carbohydrate diet in humans.

Comparative proteomics analysis of teleost intermuscular bones and ribs provides insight into their development.

BACKGROUND: Intermuscular bones (IBs) and ribs both are a part of skeletal system in teleosts, but with different developing process. The chemical composition of fish IBs and ribs as well as the underlying mechanism about their development have not been investigated. In the present study, histological structures showed that one bone cavity containing osteoclasts were existed in ribs, but not in IBs of Megalobrama amblycephala. We constructed the first proteomics map for fish bones including IBs and ribs, and identified the differentially expressed proteins between IBs and ribs through iTRAQ LC-MS/MS proteomic analysis. RESULTS: The proteins extracted from IBs and ribs at 1- to 2-year old M. amblycephala were quantified 2,342 proteins, with 1,451 proteins annotated with GO annotation in biological processes, molecular function and cellular component. A number of bone related proteins as well as pathways were identified in the study. A total of 93 and 154 differently expressed proteins were identified in comparison groups of 1-IB-vs-1-Rib and 2-IB-vs-2-Rib, which indicated the obvious differences of chemical composition between these two bone tissues. The two proteins (vitronectin b precursor and matrix metalloproteinase-2) related to osteoclasts differentiation were significantly up-regulated in ribs compared with IBs (P < 0.05), which was in accordance with the results from histological structures. In comparison groups of 1-IB-vs-2-IB and 1-Rib-vs-2-Rib, 33 and 51 differently expressed proteins were identified and the function annotation results showed that these proteins were involved in regulating bone development and differentiation. Subsequently, 11 and 13 candidate proteins in comparison group of 1-IB-vs-1-Rib and 1-IB-vs-2-IB related to bone development were validated by MRM assays. CONCLUSIONS: Our present study suggested the different key proteins involved in the composition of fish ribs and IBs as well as their growth development. These findings could provide important clues towards further understanding of fish skeletal system and the roles of proteins playing in regulating diverse biological processes in fish.

Observation of Terahertz Radiation via the Two-Color Laser Scheme with Uncommon Frequency Ratios.

In the widely studied two-color laser scheme for terahertz (THz) radiation from a gas, the frequency ratio of the two lasers is usually fixed at ω_{2}/ω_{1}=1:2. We investigate THz generation with uncommon frequency ratios. Our experiments show, for the first time, efficient THz generation with new ratios of ω_{2}/ω_{1}=1:4 and 2∶3. We observe that the THz polarization can be adjusted by rotating the longer-wavelength laser polarization and the polarization adjustment becomes inefficient by rotating the other laser polarization; the THz energy shows similar scaling laws with different frequency ratios. These observations are inconsistent with multiwave mixing theory, but support the gas-ionization or plasma-current model. This study pushes the development of the two-color scheme and provides a new dimension to explore the long-standing problem of the THz generation mechanism.