Direct laser acceleration of electrons assisted by strong laser-driven azimuthal plasma magnetic fields

A high-intensity laser beam propagating through a dense plasma drives a strong current that robustly sustains a strong quasistatic azimuthal magnetic field. The laser field efficiently accelerates electrons in such a field that confines the transverse motion and deflects the electrons in the forward direction. Its advantage is a threshold rather than resonant behavior, accelerating electrons to high energies for sufficiently strong laser-driven currents. We study the electron dynamics via a test-electron model, specifically deriving the corresponding critical current density. We confirm the model's predictions by numerical simulations, indicating energy gains two orders of magnitude higher than achievable without the magnetic field.

Energy gain by laser-accelerated electrons in a strong magnetic field

This paper deals with electron acceleration by a laser pulse in a plasma with a static uniform magnetic field B_{*}. The laser pulse propagates perpendicular to the magnetic field lines with the polarization chosen such that (E_{laser}·B_{*})=0. The focus of the work is on the electrons with an appreciable initial transverse momentum that are unable to gain significant energy from the laser in the absence of the magnetic field due to strong dephasing. It is shown that the magnetic field can initiate an energy increase by rotating such an electron, so that its momentum becomes directed forward. The energy gain continues well beyond this turning point where the dephasing drops to a very small value. In contrast to the case of purely vacuum acceleration, the electron experiences a rapid energy increases with the analytically derived maximum energy gain dependent on the strength of the magnetic field and the phase velocity of the wave. The energy enhancement by the magnetic field can be useful at high laser amplitudes, a_{0}≫1, where the acceleration similar to that in the vacuum is unable to produce energetic electrons over just tens of microns. A strong magnetic field helps leverage an increase in a_{0} without a significant increase in the interaction length.

Sanguinarine suppresses migration and metastasis in colorectal carcinoma associated with the inversion of EMT through the Wnt/β-catenin signaling

BACKGROUND

Unresectable lung or liver organ metastases of colorectal carcinoma (CRC) remain a major obstacle in clinical therapeutics. Epithelial to mesenchymal transition (EMT), a major cause of highly frequent metastasis in tumor, can be promoted by the Wnt/β-catenin pathway that is aberrantly activated in approximately 90% of CRC. This research aimed to elucidate the antimetastatic potential of sanguinarine (SG) in CRC and the underlying molecular mechanism.

METHODS

The in vitro anticancer effect of SG was determined via cell viability experiment and colony formation assay. Xenograft model of nude mice was used to confirm the antitumor effect of SG in vivo. The antimetastatic potential of SG was investigated by the metastasis model of nude mice, hematoxylin and eosin (H&E) staining, migration assay, and wound-healing analysis. Immunoblotting analysis, immunofluorescence staining, and immunohistochemistry assay were conducted to elucidate the molecular mechanism.

RESULTS

In this study, we reported that SG has a selective inhibitory effect on LoVo cells with metastatic characteristics. Furthermore, our results showed attenuation in the migration and metastatic ability of SG-treated LoVo cells and also decreased metastatic nodules of liver and lung in mice metastasis model. This was also confirmed at the molecular level via H&E staining. Further study revealed that SG had negative impacts on the Wnt/β-catenin pathway and EMT markers in LoVo cells both in vitro and in vivo.

CONCLUSIONS

Taken together, the antimetastatic potential of SG attributed to the suppression of the Wnt/β-catenin signaling, which further prevented EMT progression. SG may be of value in a potential therapy for the management of metastasis CRC.

TaqMan real-time PCR for detecting bovine viral diarrhea virus

The present study was aimed to establish a novel TaqMan real-time PCR (RTm-PCR) for detecting and typing bovine viral diarrhea virus (BVDV), and also to develop a diagnostic protocol which simplifies sample collection and processing. Universal primers and TaqMan-MGB probes were designed from the known sequences of conserved 5' - and 3'-untranslated regions (5'UTR, 3'UTR) of the NADL strain of BVDV. Prior to optimizing the assay, cDNAs were transcribed in vitro to make standard curves. The sensitivity, specificity and stability (reproducibility) were evaluated. The RTm-PCR was tested on the 312 feces specimens collected from persistently infected (PI) calves. The results showed the optimum conditions for RTm-PCR were 17.0 μmol/L primer, 7.5 μmol/L probe and 51.4°C annealing temperature. The established TaqMan RTm-PCR assay could specially detect BVDV without detecting any other viruses. Its detection limit was 1.55×100 copies/μL for viral RNA. It was 10000-fold higher than conventional PCR with excellent specificity and reproducibility. 312 samples were tested using this method and universal PCR from six dairy farms, respectively. Positive detections were found in 49 and 44 feces samples, respectively. The occurrence rate was 89.80%. In conclusion, the established TaqMan RTm-PCR could rapidly detect BVDV and effectively identify PI cattle. The detection limit of RTm-PCR was 1.55 copies/μL. It will be beneficial for enhancing diagnosis and therapy efficacy and reduce losses in cattle farms.

Deflection of a reflected intense circularly polarized light beam induced by asymmetric radiation pressure

A deflection effect of an intense laser beam with spin angular momentum is revealed theoretically by an analytical modeling using radiation pressure and momentum balance of laser plasma interaction in the relativistic regime as a deviation from the law of reflection. The reflected beam deflects out of the plane of incidence with a deflection angle up to several milliradians, when a nonlinear polarized laser, with the intensity I_{0}∼10^{19}W/cm^{2} and duration around tens of femtoseconds, is obliquely incident and reflected by an overdense plasma target. This effect originates from the asymmetric radiation pressure caused by spin angular momentum of the laser photons. The dependence of the deflection angle of a Gaussian-type laser on the parameters of laser pulse and plasma foil is theoretically derived, which is also confirmed by three-dimensional particle-in-cell simulations of circularly polarized laser beams with the different intensity and pulse duration.

Radiation reaction as an energy enhancement mechanism for laser-irradiated electrons in a strong plasma magnetic field

Conventionally, friction is understood as a mechanism depleting a physical system of energy and as an unavoidable feature of any realistic device involving moving parts. In this work, we demonstrate that this intuitive picture loses validity in nonlinear quantum electrodynamics, exemplified in a scenario where spatially random friction counter-intuitively results in a highly directional energy flow. This peculiar behavior is caused by radiation friction, i.e., the energy loss of an accelerated charge due to the emission of radiation. We demonstrate analytically and numerically how radiation friction can dramatically enhance the energy gain by electrons from a laser pulse in a strong magnetic field that naturally arises in dense laser-irradiated plasma. We find the directional energy boost to be due to the transverse electron momentum being reduced through friction whence the driving laser can accelerate the electron more efficiently. In the considered example, the energy of the laser-accelerated electrons is enhanced by orders of magnitude, which then leads to highly directional emission of gamma-rays induced by the plasma magnetic field.

TPD7 inhibits the growth of cutaneous T cell lymphoma H9 cell through regulating IL-2R signalling pathway

IL‐2R pathway is a key regulator in the development of immune cells and has emerged as a promising drug target in cancer treatment, but there is a scarcity of related inhibitors. TPD7 is a novel biphenyl urea taspine derivate, which has been shown anti‐cancer effect. Here, we demonstrated the anti‐cancer activity of TPD7 in cutaneous T cell lymphoma and investigated the underlying mechanism of TPD7 through IL‐2R signalling. The inhibitory effect of TPD7 on cell viability exhibited a strong correlation with the expression level of IL‐2R, and cutaneous T cell lymphoma H9 and HUT78 cells were most sensitive to TPD7. TPD7 was nicely bound to IL‐2R and down‐regulated the mRNA and protein levels of IL‐2R. Furthermore, TPD7 suppressed the downstream cascades of IL‐2R including JAK/STAT, PI3K/AKT/mTOR and PLCγ/Raf/MAPK signalling, resulting in Bcl‐2 mitochondrial apoptosis pathway and cell cycle proteins CDK/Cyclins regulation. And, these were verified by flow cytometry analysis that TPD7 facilitated cell apoptosis in H9 cells via mitochondrial pathway and impeded cell cycle progression at G2/M phase. TPD7 is a novel anti‐cancer agent and may be a potential candidate for cutaneous T cell lymphoma treatment by regulating IL‐2R signalling pathway.

EDACO, a derivative of myricetin, inhibits the differentiation of Gaoyou duck embryonic osteoclasts in vitro

1. This study determined the effects of (E)-3-(2-(4-(3-(2,4-dimethoxyphenyl)acryloyl)phenoxy)ethoxy)-5,7-dimethoxy-2-(3,4,5-trimethoxyphenyl)-4H-chromen-4-one (EDACO) on the differentiation of Gaoyou duck embryonic osteoclasts cultured in vitro. 2. Bone marrow mononuclear cells (BM-MNC) were collected from 23-d-old Gaoyou duck embryos and induced by macrophage colony-stimulating factor and receptor activator of nuclear factor κB ligand in the presence of EDACO at different concentrations (i.e. 10, 20, 40, 80 and 160 µM). Tartrate-resistant acid phosphatase (TRAP) staining and resorption ability determination were conducted. 3. Results suggested that EDACO suppressed the shaping of positive multinucleated cells and the number of TRAP-positive cells in the 20, 40, 80 and 160 μM EDACO groups was significantly decreased (P < 0.05 or P < 0.01). Besides, the absorption activity of differentiated duck embryonic osteoclasts was significantly inhibited (P < 0.05) in both 80 and 160 μM EDACO groups. 4. Overall, EDACO can inhibit the differentiation of BM-MNC into mature osteoclasts in duck embryos.1.

[Rush poppers use and risks of human papillomavirus infection among men who have sex with men in Urumqi: mediation effect through high-risk sexual behaviors]

Objective: To study the prevalence of rush poppers use among men who have sex with men (MSM) in Urumqi and to analyze the mediating effect of high-risk sexual behavior between the use of rush poppers and human papillomavirus (HPV) infection. Methods: From January to June 2018, 651 MSM were recruited through network and publicity. Data was collected by using online questionnaire and anal swab were collected from them for HPV genotyping. According to Baron and Kenny's criterion, multivariate logistic regression models was used to analyze the mediation effect of high-risks sexual behaviors (multiple sexual partners, anal intercourse condom use) between rush poppers use and HPV infection. Results: A total of 651 subjects were (32.0±8.0) years old, and 174 subjects (26.7%) had ever used rush poppers in the past 6 months, while 350 subjects (46.9%) had more than 2 sexual partners and 188 subjects (28.9%) did not use anal condom. After adjusting age and marital status, rush poppers use was associated with HPV infection (OR (95%CI) was 2.34 (1.63-3.36), P<0.05), and sexual partners in the past 6 months (OR (95%CI) was 2.72 (1.89-3.93), P<0.05).After adjustment for age, marital status, sexual partners in the past 6 months, and anal condom use, rush poppers use was still associated with HPV infection (OR (95%CI) was 2.21 (1.53-3.19), P<0.05).After adjustment and adjustment of age, marital status, rush poppers use and anal sex condom use, the number of sexual partners at nearly 6 months was still associated with HPV infection (OR (95%CI) was 1.46 (1.05-2.04), P<0.05). Conclusion: Sexual partners in the past 6 months have a mediation effect between rush poppers use and HPV infection in Urumqi. For the prevention of sexually transmitted diseases, we should focus on rush poppers use.

Creation of Electron-Positron Pairs in Photon-Photon Collisions Driven by 10-PW Laser Pulses

A novel approach is proposed to demonstrate the two-photon Breit-Wheeler process by using collimated and wide-bandwidth γ-ray pulses driven by 10-PW lasers. Theoretical calculations suggest that more than 3.2×10^{8} electron-positron pairs with a divergence angle of 7° can be created per shot, and the signal-to-noise ratio is higher than 10^{3}. The positron signal, which is roughly 100 times higher than the detection limit, can be measured by using the existing spectrometers. This approach, which could demonstrate the e^{-}e^{+} pair creation process from two photons, would provide important tests for two-photon physics and other fundamental physical theories.

Visible light communication using dual camera on one smartphone

Dual camera is becoming increasingly prevalent among smartphone camera schemes these days. This paper demonstrates a system prototype by using the color and monochrome cameras on one smartphone simultaneously for visible light communication. To achieve this, we propose a novel dual-modulation scheme. The baseband signal is firstly modulated by color ratio modulation-color shift keying (CRM-CSK) to broadcast color ratio information that can be distinguished by the color camera. Next to it, gray level modulation (GLM) is utilized to generate CRM symbols with gray levels that can be distinguished by the monochrome camera. Our experiment shows a significant improvement in the downlink data rate of the optical camera communication (OCC) using a single light source.

Space-based observations of crustal deflections for drought characterization in Brazil

Widespread environmental impacts of frequent drought episodes in Brazil have resulted in several drought-related diagnostics studies. However, the potential of many "opportunistic sensors", such as the Global Positioning System (GPS), has not yet been considered in hydrological hazard monitoring in Brazil. In this study, the response of the Earth's crust to Brazil's 2012-2015 drought event in different structural provinces is analyzed by comparing GPS-observed vertical crustal deformations (VCDs) with the terrestrial water storage (TWS) derived from the Gravity Recovery and Climate Experiment (GRACE). The results indicate that there is no spatial correlation between annual amplitudes of the TWS and VCDs in different structural provinces apart from the purely elastic response of the crust to TWS dynamics, at almost all the 39 GPS stations that were analyzed. However, approximately 15% of the monitoring stations show that VCD leads TWS with a phase lag of 2-4 months. Errors associated with VCD and TWS are within the accepted range for space geodetic techniques (i.e., GPS and GRACE) and despite the need for further investigation, the phase lead seems to be associated with rainfall, which impacts the TWS through the hydrographs. Overall, the GPS-based drought index (DI_VCD) reflects the water depletion in many regions of Brazil, which agrees with the GRACE-based DI_TWS in terms of the Spearman correlation coefficient (ranging from 0.4 to 0.9) in the Amazon, Tocantins, La Plata, and São Francisco river basins. This agreement confirms the drought persistence during the study period and that DI_VCD can be used to monitor hydrological droughts. In regions in which DI_TWS sufficiently agrees with DI_VCD (48% of the sites), near real-time drought monitoring is feasible. This could be useful in the optimization of models for the forward prediction of drought events in other regions worldwide, where GPS vertical displacements strongly correlate with hydrological GRACE signals.

[The changes of adipocytokines after surgery in OSAHS patients with insulin resistance]

Objective:To evaluate the changes of adipocytokines after surgery in OSAHS patients with insulin resistance.Method:Eighty-four OSAHS patients were enrolled in this study and divided into two group based on insulin resistance: IR group(n=52) and non-IR group(n=32). All patients received UPPP surgery. The levels of chemerin,visfatin and obestatin were measured before and one week after surgery.Result:Before surgery,the levels of chemerin,visfatin and HOMA-IR in IR group were higher than those in non-IR group,while level of obestatin was lower than those in non-IR group. One week after surgery,the level of obestatin in IR group was lower than those in non-IR group. The levels of chemerin,visfatin and HOMA-IR were decreased while obestatin increased after surgery. Correlation analysis showed that UPPP surgery was negatively related with △chemerin（r=-0.685，P<0.05）and △HOMA-IR（r=-0.622，P<0.05）.△HOMA-IR was positively associated with △chemerin（r=0.634，P<0.05）.Conclusion:The levels of chemerin,visfatin and obestatin are significantly improved after UPPP surgery. Level of chemerin seems to have a close relationship with IR.