Probing hidden leptonic scalar portals using the NA64 experiment at CERN.

In this study, we demonstrate the potential of the NA64 experiment at CERN SPS to search for New Physics processes involving transitions after the collision of 100 GeV electrons with target nuclei. A new Dark Sector leptonic portal in which a scalar boson could be produced in the lepton-flavor-changing bremsstrahlung-like reaction, , is used as benchmark process. In this work, we develop a realistic Monte Carlo simulation of the NA64 experimental setup implementing the differential and total production cross-section computed at exact tree-level and applying the Weiszäcker-Williams phase space approximation.

Dark-Sector Search via Pion-Produced η and η^{'} Mesons Decaying Invisibly in the NA64h Detector.

We present the first results from a proof-of-concept search for dark sectors via invisible decays of pseudoscalar η and η^{'} mesons in the NA64h experiment at the CERN SPS. Our novel technique uses the charge-exchange reaction of 50 GeV π^{-} on nuclei of an active target as the source of neutral mesons. The η,η^{'}→invisible events would exhibit themselves via a striking signature-the complete disappearance of the incoming beam energy in the detector.

First Results in the Search for Dark Sectors at NA64 with the CERN SPS High Energy Muon Beam.

We report the first search for dark sectors performed at the NA64 experiment employing a high energy muon beam and a missing energy-momentum technique. Muons from the M2 beamline at the CERN Super Proton Synchrotron with a momentum of 160  GeV/c are directed to an active target. The signal signature consists of a single scattered muon with momentum <80  GeV/c in the final state, accompanied by missing energy, i.

Search for Light Dark Matter with NA64 at CERN.

Thermal dark matter models with particle χ masses below the electroweak scale can provide an explanation for the observed relic dark matter density. This would imply the existence of a new feeble interaction between the dark and ordinary matter. We report on a new search for the sub-GeV χ production through the interaction mediated by a new vector boson, called the dark photon A^{'}, in collisions of 100 GeV electrons with the active target of the NA64 experiment at the CERN SPS.

Search for a New B-L Z^{'} Gauge Boson with the NA64 Experiment at CERN.

A search for a new Z^{'} gauge boson associated with (un)broken B-L symmetry in the keV-GeV mass range is carried out for the first time using the missing-energy technique in the NA64 experiment at the CERN SPS. From the analysis of the data with 3.22×10^{11} electrons on target collected during 2016-2021 runs, no signal events were found.

Probing the explanation of the muon (g-2) anomaly and thermal light dark matter with the semi-visible dark photon channel.

We report the results of a search for a new vector boson ( ) decaying into two dark matter particles of different mass. The heavier particle subsequently decays to and an off-shell Dark Photon . For a sufficiently large mass splitting, this model can explain in terms of new physics the recently confirmed discrepancy observed in the muon anomalous magnetic moment at Fermilab.

Constraints on New Physics in Electron g-2 from a Search for Invisible Decays of a Scalar, Pseudoscalar, Vector, and Axial Vector.

We performed a search for a new generic X boson, which could be a scalar (S), pseudoscalar (P), vector (V), or an axial vector (A) particle produced in the 100 GeV electron scattering off nuclei, e^{-}Z→e^{-}ZX, followed by its invisible decay in the NA64 experiment at CERN. No evidence for such a process was found in the full NA64 dataset of 2.84×10^{11} electrons on target.

Hunting down the X17 boson at the CERN SPS.

Recently, the ATOMKI experiment has reported new evidence for the excess of events with a mass 17 MeV in the nuclear transitions of He, that they previously observed in measurements with Be. These observations could be explained by the existence of a new vector boson. So far, the search for the decay with the NA64 experiment at the CERN SPS gave negative results.

Search for Axionlike and Scalar Particles with the NA64 Experiment.

We carried out a model-independent search for light scalar (s) and pseudoscalar axionlike (a) particles that couple to two photons by using the high-energy CERN SPS H4 electron beam. The new particles, if they exist, could be produced through the Primakoff effect in interactions of hard bremsstrahlung photons generated by 100 GeV electrons in the NA64 active dump with virtual photons provided by the nuclei of the dump. The a(s) would penetrate the downstream HCAL module, serving as a shield, and would be observed either through their a(s)→γγ decay in the rest of the HCAL detector, or as events with a large missing energy if the a(s) decays downstream of the HCAL.

Direct fabrication of PDMS waveguides via low-cost DUV irradiation for optical sensing.

We demonstrate the fabrication of single mode optical waveguides by irradiating polydimethylsiloxane (PDMS) with a low cost Hg lamp through a conventional quartz mask. By increasing the refractive index of the irradiated areas, waveguiding is achieved with an attenuation of 0.47 dB/cm at a wavelength of 635 nm.

Structural basis of highly conserved ribosome recycling in eukaryotes and archaea.

Ribosome-driven protein biosynthesis is comprised of four phases: initiation, elongation, termination and recycling. In bacteria, ribosome recycling requires ribosome recycling factor and elongation factor G, and several structures of bacterial recycling complexes have been determined. In the eukaryotic and archaeal kingdoms, however, recycling involves the ABC-type ATPase ABCE1 and little is known about its structural basis.

Stem and osteotomy length are critical for success of the transfemoral approach and cementless stem revision.

Background: The transfemoral approach is an extensile surgical approach that is performed routinely to facilitate cement and implant removal and improve exposure for revision stem implantation. Previous studies have looked at clinical results of small patient groups. The factors associated with fixation failure of cementless revision stems when using this approach have not been examined.

Differential Rayleigh scattering method for measurement of polarization and intermodal beat length in optical waveguides and fibers.

We propose a modification of the Rayleigh scattering method, which allows for measurement of polarization and intermodal beat length in single-mode and few-mode channel waveguides and optical fibers. A significant sensitivity increase is achieved by taking two high-resolution photographs in oblique scattered light of π-shifted intensity distributions produced by interference of polarization or spatial modes and applying Fourier analysis to the differential image. In the case of polarization beat length measurements, the π-phase shift is obtained by switching the polarization state at the fiber input, while in intermodal measurements, the π-phase shifting is realized by changing the excitation conditions.

Structure of the no-go mRNA decay complex Dom34-Hbs1 bound to a stalled 80S ribosome.

No-go decay (NGD) is a mRNA quality-control mechanism in eukaryotic cells that leads to degradation of mRNAs stalled during translational elongation. The key factors triggering NGD are Dom34 and Hbs1. We used cryo-EM to visualize NGD intermediates resulting from binding of the Dom34-Hbs1 complex to stalled ribosomes.

Safety of ultra-rush titration of sublingual immunotherapy in asthmatic children with tree-pollen allergy.

The recommendation to use sublingual-swallow immunotherapy (SLIT) in children and adults with allergic rhinitis has been established over the past decade. Recently, ultra-rush titration of SLIT has become more and more common, raising concerns about its safety in children with asthma. Fifty-four children with asthma and adolescents aged 6–14 with documented allergic disease because of tree pollen (birch and possibly alder and/or hazel) from 14 study centers in Germany participated in a randomized, double-blind, and placebo-controlled study.

Development of an allergen extract for sublingual immunotherapy--evaluation of Staloral.

Background: Specific immunotherapy (IT) is an effective treatment for rhinitis and asthma caused by aeroallergens sensitization. Sublingual IT (SLIT) was introduced to solve the problem of systemic reactions to subcutaneous IT (SCIT) and developed to represent an actual treatment option. It is now generally accepted that allergen doses much higher than those administered by SCIT must be used to achieve clinical efficacy on allergic symptoms.

Genetic stability of vaccine strain Salmonella Typhi Ty21a over 25 years.

The attenuated live bacterial vaccine strain Salmonella enterica Serovar Typhi Ty21a is the main constituent of Vivotif, the only licensed oral vaccine against typhoid fever. The strain was developed in the 1970s by chemical mutagenesis. In the course of this mutagenesis, a number of mutations were introduced into the vaccine strain.

Vivotif--a 'magic shield' for protection against typhoid fever and delivery of heterologous antigens.

The attenuated Salmonella typhi strain Ty21a is the main constituent of Vivotif, the only attenuated live oral vaccine against typhoid fever. In comparison with antibiotics, the 'magic bullets' which Paul Ehrlich was striving for to treat infectious diseases, this vaccine should be viewed as a 'magic shield', because rather than treating typhoid fever after the infection has started, immunisation with this vaccine strain prevents infection and disease by the induction of specific immune responses. Ty21a is also an attractive carrier for the delivery of heterologous antigens.

[Medium-term results after m. vastus medialis obliquus-plasty for lateral patellar dislocation].

Progressive retropatellar arthrosis is often seen in dated rigid distal realignment (i.e. osteotomy of tuberositas) at long-term follow-ups.

[Principles of fixation of the cementless modular revision stem Revitan].

Aim And Method: To analyse the femoral fixation of a modular cementless revision endoprosthesis, eight prosthetic combinations of the Revitan-System (Centerpulse, Winterthur, Switzerland) were implanted in four cadavers. On three cadavers a curved revision Revitan stem was implanted by an endofemoral approach on one side and by a transfemoral approach on the contralateral side. On the fourth cadaver a straight Revitan stem was implanted on one side and a curved Revitan stem on the contralateral side using a transfemoral approach.

Classification of abnormal fundus autofluorescence patterns in the junctional zone of geographic atrophy in patients with age related macular degeneration.

Aim: To describe and classify patterns of abnormal fundus autofluorescence (FAF) in the junctional zone of geographic atrophy (GA) in patients with age related macular degeneration.

Methods: Digital FAF images were recorded in 164 eyes of 107 patients using a confocal scanning laser ophthalmoscope (cSLO; excitation 488 nm, detection above 500 nm) as part of a prospective multicentre natural history study (FAM Study). FAF images were obtained in accordance with a standardised protocol for digital image acquisition and generation of mean images after automated alignment.

The ALEU2 gene--a new component for an Arxula adeninivorans-based expression platform.

The ALEU2 gene, encoding beta-isopropylmalate dehydrogenase, was isolated from the non-conventional yeast Arxula adeninivorans. The isolated gene harbours an open reading frame of 1086 bp, encoding a putative protein of 362 amino acids. The derived protein sequence shares a high degree of homology with other fungal beta-isopropylmalate dehydrogenases thus confirming the identity of the gene.

High-level production and secretion of recombinant proteins by the dimorphic yeast Arxula adeninivorans.

The non-conventional dimorphic thermo- and salt-resistant yeast Arxula adeninivorans has been developed as a host for heterologous gene expression. For assessment of the system two model genes have been selected: the GFP gene encoding the intracellular green fluorescent protein, and the HSA gene encoding the secreted human serum albumin. The expression system includes two host strains, namely A.

Strain and process development for the production of human cytokines in Hansenula polymorpha.

The early status of strain development for the production of interleukin (IL)-6, IL-8, IL-10, and interferon (IFN) gamma is described. The general approach to generating such strains was to amplify gene sequences encoding the mature forms of the various cytokines by PCR from commercially available cDNA sources. The design of the amplificates allowed an in-frame fusion to an MFalpha1 leader segment contained in two basic expression vectors, pFPMT121-MFalpha1 and pTPSMT-MFalpha1.

PIASy, a nuclear matrix-associated SUMO E3 ligase, represses LEF1 activity by sequestration into nuclear bodies.

The Wnt-responsive transcription factor LEF1 can activate transcription in association with beta-catenin and repress transcription in association with Groucho. In search of additional regulatory mechanisms of LEF1 function, we identified the protein inhibitor of activated STAT, PIASy, as a novel interaction partner of LEF1. Coexpression of PIASy with LEF1 results in potent repression of LEF1 activity and in covalent modification of LEF1 with SUMO.