1,002 research outputs found
Leading logarithm calculation of the e^+ e^- -> e^+ \nu_e \bar{u} d cross section
We analytically evaluate in the leading logarithm approximation the
differential cross section for e^+ e^- -> e^+ \nu_e \bar{u} d. We compare our
order \alpha^4 \alpha_s^0 leading-log result to the order \alpha^4 \alpha_s^0
exact result obtained from the GRC4F Monte Carlo program. Finally we use the
Gluck, Reya, Schienbien distribution of partons in a virtual photon, which
incorporates both evolution and nonperturbative strong interaction
contributions, to obtain better estimates of the differential cross section.Comment: 10 pages including 9 figure
Recommended from our members
Isonitrile-responsive and bioorthogonally removable tetrazine protecting groups.
In vivo compatible reactions have a broad range of possible applications in chemical biology and the pharmaceutical sciences. Here we report tetrazines that can be removed by exposure to isonitriles under very mild conditions. Tetrazylmethyl derivatives are easily accessible protecting groups for amines and phenols. The isonitrile-induced removal is rapid and near-quantitative. Intriguingly, the deprotection is especially effective with (trimethylsilyl)methyl isocyanide, and serum albumin can catalyze the elimination under physiological conditions. NMR and computational studies revealed that an imine-tautomerization step is often rate limiting, and the unexpected cleavage of the Si-C bond accelerates this step in the case with (trimethylsilyl)methyl isocyanide. Tetrazylmethyl-removal is compatible with use on biomacromolecules, in cellular environments, and in living organisms as demonstrated by cytotoxicity experiments and fluorophore-release studies on proteins and in zebrafish embryos. By combining tetrazylmethyl derivatives with previously reported tetrazine-responsive 3-isocyanopropyl groups, it was possible to liberate two fluorophores in vertebrates from a single bioorthogonal reaction. This chemistry will open new opportunities towards applications involving multiplexed release schemes and is a valuable asset to the growing toolbox of bioorthogonal dissociative reactions
Portable Device for Continuous Sensing with Rapidly Pulsed LEDs – Part 1: Rapid On-the-fly Processing of Large Data Streams using an Open Source Microcontroller with Field Programmable Gate Array
We designed a portable system using an open source microcontroller (μC) with built-in field programmable gate array (FPGA) for on-the-fly data acquisition and processing of optical data generated from rapidly pulsed infrared light emitting diodes (IR LEDs) for optical sensing of gases. The system is used for rapid pulse generation (ca. 2 μs short pulses with a typical repetition rate of 1 kHz) to drive the IR LED, as well as for the optical sensing data acquisition and processing on-thefly large data streams of ca. 2 Gbit/s. The flexibility and performance of the system is demonstrated. Each of the digitally processed signal pulses yielded one data point of analytical signal in time as a quasi-continuous data stream produced at a rate of between 1000 and 0.1 Hz. This microcontroller-based portable open source platform is then implemented in on-the-fly data acquisition and processing, of analytical signals enabling continuous gas sensing
Persistence Wins: Long-Term Agricultural Conservation Outreach Pays Off
This article discusses the lesson learned from an Extension, state, and federal agency coordinated water quality project that was formally started in 1995. In the project, educational programing was provided, high risk areas were identified, and BMPs were implemented on these areas. The net result of BMP implementation was a 38% improvement in South Dakota Bad River water quality. This improvement was attributed to Extension and others providing leadership on: 1) the development of local learning communities and 2) identification and implementing BMP\u27s in high risk areas. This work demonstrates that Extension can make a difference
Copper-induced conformational change in a marsupial prion protein repeat peptide probed using FTIR spectroscopy
AbstractWe report the first Fourier transform infrared analysis of prion protein (PrP) repeats and the first study of PrP repeats of marsupial origin. Large changes in the secondary structure and an increase in hydrogen bonding within the peptide groups were evident from a red shift of the amide I band by >7 cm−1 and an approximately five-fold reduction in amide hydrogen–deuterium exchange for peptide interacting with Cu2+ ions. Changes in the tertiary structure upon copper binding were also evident from the appearance of a new band at 1564 cm−1, which arises from the ring vibration of histidine. The copper-induced conformational change is pH dependent, and occurs at pH >7
Evaluation of FOXM1 inhibitor (FDI-6) as a potential therapeutic molecule for small cell lung cancer
Lung cancer is the leading cause of cancer deaths accounting for about 22% of all cancer related cases in both males and females. Lung cancers are broadly grouped into two types mainly small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC) with SCLC accounting for about 15% of all lung cancer cases. SCLC is different from NSCLC because in most cases it originates centrally in the bronchi and is frequently seen in smokers. SCLC is aggressive and one of the most malignant forms of tumor characterized by uncontrolled rapid growth of certain cells in the lungs. SCLC displays poor prognosis because of early-stage metastasis, acquisition of chemoresistance, and has a high rate of recurrence. One of major drivers of chemoresistance is the transcription factor Forkhead box protein M1 (FOXM1) that is responsible for modulating cell cycle proliferation, maintenance of genomic stability, DNA damage response, and cell differentiation in numerous tumor entities. In order to explore properties of SCLC cancer cell lines, human non-bone metastatic SBC3, bone metastatic SBC5, H1688, and murine (RPM) cells were treated with a FOXM1 inhibitor known as FDI-6. As a transcription factor FOXMI binds sequence-specific motifs on DNA through its DNA-binding domain activating proliferation and differentiation-associated genes. Anomalous overexpression of FOXMI is a crucial characteristic in oncogenesis and the development of SCLC. FDI-6 is a novel small molecule inhibitor of FOXM1, and it works by binding directly to FOXM1 protein, to displace FOXM1 from genomic targets in SCLC cells prompting concomitant translational downregulation. Functional assays performed confirm that FDI-6 is a viable FOXMI inhibitor showing therapeutic efficacies in SCLC.https://digitalcommons.unmc.edu/surp2021/1044/thumbnail.jp
Differential Susceptibility of Human Peripheral Blood T Cells to Suppression by Environmental Levels of Sodium Arsenite and Monomethylarsonous Acid
Human exposure to arsenic in drinking water is known to contribute to many different health outcomes such as cancer, diabetes, and cardiopulmonary disease. Several epidemiological studies suggest that T cell function is also altered by drinking water arsenic exposure. However, it is unclear how individual responses differ to various levels of exposure to arsenic. Our laboratory has recently identified differential responses of human peripheral blood mononuclear cell (HPMBC) T cells as measured by polyclonal T cell activation by mitogens during sodium arsenite exposure. T cells from certain healthy individuals exposed to various concentrations (1–100 nM) of arsenite in vitro showed a dose-dependent suppression at these extremely low concentrations (∼0.1–10 ppb) of arsenite, whereas other individuals were not suppressed at low concentrations. In a series of more than 30 normal donors, two individuals were found to be sensitive to low concentration (10 nM equivalent ∼1 ppb drinking water exposure) to sodium arsenite-induced inhibition of T cell proliferation produced by phytohemagglutinin (PHA) and anti-CD3/anti-CD28. In an arsenite-susceptible individual, arsenite suppressed the activation of Th1 (Tbet) cells, and decreased the percentage of cells in the double positive Th17 (RORγt) and Treg (FoxP3) population. While the majority of normal blood donors tested were not susceptible to inhibition of proliferation at the 1–100 nM concentrations of As+3, it was found that all donors were sensitive to suppression by 100 nM monomethylarsonous acid (MMA+3), a key metabolite of arsenite. Thus, our studies demonstrate for the first time that low ppb-equivalent concentrations of As+3 are immunosuppressive to HPBMC T cells in some individuals, but that most donor HPBMC are sensitive to suppression by MMA+3 at environmentally relevant exposure levels
Objective No-Reference Stereoscopic Image Quality Prediction Based on 2D Image Features and Relative Disparity
Stereoscopic images are widely used to enhance the viewing experience of three-dimensional (3D) imaging and communication system. In this paper, we propose an image feature and disparity dependent quality evaluation metric, which incorporates human visible system characteristics. We believe perceived distortions and disparity of any stereoscopic image are strongly dependent on local features, such as edge (i.e., nonplane areas of an image) and nonedge (i.e., plane areas of an image) areas within the image. Therefore, a no-reference perceptual quality assessment method is developed for JPEG coded stereoscopic images based on segmented local features of distortions and disparity. Local feature information such as edge and non-edge area based relative disparity estimation, as well as the blockiness and the edge distortion within the block of images are evaluated in this method. Subjective stereo image database is used for evaluation of the metric. The subjective experiment results indicate that our metric has sufficient prediction performance
- …