TDCRPy: A python package for TDCR measurements.

The TDCR (Triple-to-Double Coincidence Ratio) measurement technique is a primary standardization method used by metrology laboratories to accurately determine the activity of radioactive solutions, particularly for radionuclides unsuitable for traditional coincidence counting methods, such as pure beta emitters. The TDCR method leverages a liquid scintillation counter equipped with three photomultiplier tubes (PMTs). This paper introduces TDCRPy, a novel Python package developed by the BIPM, designed to calculate detection efficiency of liquid scintillation counters using Monte Carlo simulations and decay data evaluations from the Decay Data Evaluation Project (DDEP).

Phosphoric acid salts of amino acids as a source of oligopeptides on the early Earth.

Because of their unique proton-conductivity, chains of phosphoric acid molecules are excellent proton-transfer catalysts. Here we demonstrate that this property could have been exploited for the prebiotic synthesis of the first oligopeptide sequences on our planet. Our results suggest that drying highly diluted solutions containing amino acids (like glycine, histidine and arginine) and phosphates in comparable concentrations at elevated temperatures (ca.

Prebiotic Synthesis of 3',5'-Cyclic Adenosine and Guanosine Monophosphates through Carbodiimide-Assisted Cyclization.

3',5'-Cyclic nucleotides play a fundamental role in modern biochemical processes and have been suggested to have played a central role at the origin of terrestrial life. In this work, we suggest that a formamide-based systems chemistry might account for their availability on the early Earth. In particular, we demonstrate that in a liquid formamide environment at elevated temperatures 3',5'-cyclic nucleotides are obtained in good yield and selectivity upon intramolecular cyclization of 5'-phosphorylated nucleosides in the presence of carbodiimides.

Measurement of the activity and determination of the half-life of Ac at POLATOM.

A method for absolute measurements of the Ac activity in equilibrium with its progeny was developed. Measurements were performed using the triple-to-double coincidence ratio (TDCR) method in two different TDCR counters. The activity concentration of an Ac solution was determined and the solution was sent to the SIR system for a comparison.

The international reference system for beta-particle emitting radionuclides: Validation through the pilot study CCRI(II)-P1.Co-60.

The Bureau International des Poids et Mesures (BIPM) is developing a new transfer instrument to extend its centralized services for assessing the international equivalence of radioactive standards to new radionuclides. A liquid scintillation counter using the triple/double coincidence ratio method is being studied and tested in the CCRI(II)-P1.Co-60 pilot study.

Liquid scintillation counting of electrons from internal conversion for quantifying Cd activity using a 3-photomultiplier tube system and a specific spectral unfolding.

As part of the international key comparison CCRI(II)-K2.Cd-109.2021, the BIPM has implemented a specific method to measure the activity of Cd solution - a key radionuclide in the calibration of gamma-ray spectrometers.

Test of a digitizer to process the pulse signal from the 3 photomultiplier tubes of a TDCR liquid scintillation counter.

The BIPM is developing a new service for international key comparisons in radionuclide metrology. The system, called ESIR, is based on a liquid scintillation counter using the Triple-to-Double Coincidence Ratio (TDCR) technique. The aim is to produce an international reference that can be reproduced over several decades of time in order to compare the calibration capabilities of National Metrology Institutes (NMIs).

Optimization of 1,2,4-Triazole-3-thiones toward Broad-Spectrum Metallo-β-lactamase Inhibitors Showing Potent Synergistic Activity on VIM- and NDM-1-Producing Clinical Isolates.

Metallo-β-lactamases (MBLs) contribute to the resistance of Gram-negative bacteria to carbapenems, last-resort antibiotics at hospital, and MBL inhibitors are urgently needed to preserve these important antibacterial drugs. Here, we describe a series of 1,2,4-triazole-3-thione-based inhibitors displaying an α-amino acid substituent, which amine was mono- or disubstituted by (hetero)aryl groups. Compounds disubstituted by certain nitrogen-containing heterocycles showed submicromolar activities against VIM-type enzymes and strong NDM-1 inhibition ( = 10-30 nM).

Implementation of fetal clinical exome sequencing: Comparing prospective and retrospective cohorts.

Purpose: We compared the diagnostic yield of fetal clinical exome sequencing (fCES) in prospective and retrospective cohorts of pregnancies presenting with anomalies detected using ultrasound. We evaluated factors that led to a higher diagnostic efficiency, such as phenotypic category, clinical characterization, and variant analysis strategy.

Methods: fCES was performed for 303 fetuses (183 ongoing and 120 ended pregnancies, in which chromosomal abnormalities had been excluded) using a trio/duo-based approach and a multistep variant analysis strategy.

4-Alkyl-1,2,4-triazole-3-thione analogues as metallo-β-lactamase inhibitors.

In Gram-negative bacteria, the major mechanism of resistance to β-lactam antibiotics is the production of one or several β-lactamases (BLs), including the highly worrying carbapenemases. Whereas inhibitors of these enzymes were recently marketed, they only target serine-carbapenemases (e.g.

Evaluation of a First-in-Class Proteasome Inhibitor in Patients With Moderate to Severe Rosacea.

Background: Novel, effective, affordable therapies for rosacea are needed. Innovative methods of assessing response for rosacea treatments are needed as well. This trial was designed to evaluate efficacy and safety of ACU-D1, a novel inhibitor of the 26S protea-some for the treatment of moderate to severe rosacea in a first in human pilot study.

HPGe/BGO Compton suppression system: Monte Carlo study of radiation monitoring system for failed fuel detection in sodium-cooled fast reactors.

Fuel failures detection and monitoring is a key issue in sodium-cooled fast reactor operation. This detection is based on monitoring the signal of fission products using dedicated radiation monitoring systems based on gamma spectrometry or neutron counting. In this context, the French Alternative Energies and Atomic Energy Commission (CEA) investigates and developpes a Compton suppression system composed by a high-purity germanium diode, a bismuth germanate scintillator and a dedicated digital signal processing allowing filtering coincidences.

On the photomultiplier-tube asymmetry in TDCR systems.

The responses of the three photomultiplier tubes (PMTs) in a triple-to-double coincidence ratio (TDCR) liquid scintillation (LS) system are often not identical. Such asymmetries can have a significant influence on activity determinations. The problem is often solved by means of a minimization algorithm which can easily be applied when analytical methods are used for the efficiency calculation, as is usually done for pure beta emitters.

Formic Acid, a Ubiquitous but Overlooked Component of the Early Earth Atmosphere.

Terrestrial volcanism has been one of the dominant geological forces shaping our planet since its earliest existence. Its associated phenomena, like atmospheric lightning and hydrothermal activity, provide a rich energy reservoir for chemical syntheses. Based on our laboratory simulations, we propose that on the early Earth volcanic activity inevitably led to a remarkable production of formic acid through various independent reaction channels.

N-(2-Ethylhexyl)carbazole: A New Fluorophore Highly Suitable as a Monomolecular Liquid Scintillator.

The synthesis, photophysical properties, and applications in scintillation counting of N-(2-ethylhexyl)carbazole (EHCz) are reported. This molecule displays all of the required characteristics for an efficient liquid scintillator (emission wavelength, scintillation yield), and can be used without any extra fluorophores. Thus, its scintillation properties are discussed, as well as its fast neutron/gamma discrimination.

Localized delivery of a lipophilic proteasome inhibitor into human skin for treatment of psoriasis.

Purpose: Pentaerythritol tetrakis (3,5-di-tert-butyl-4-hydroxyhydrocinnamate) (PTTC) is a cinnamate tetraester with proteasome inhibitor activity, which may be used as a topical treatment in psoriasis, but has a computed log P of 23. The objective of this in vitro study was to determine the intradermal delivery, skin irritation and potential efficacy of PTTC in treating psoriasis.

Methods: Solubility studies were performed to find a suitable vehicle for PTTC.

Acute ischemic stroke in a 19 month old following minor head trauma: case report and review of the literature.

Minor head trauma is a very rare cause of ischemic stroke in the pediatric population. We describe a nineteen month old patient who developed left hemiparesis and subsequently left facial palsy after a fall. MRI of the brain showed hypodensities in the basal ganglia, internal capsule and caudate nucleus consistent with stroke.

Adolescent idiopathic scoliosis and the presence of spinal cord abnormalities. Preoperative magnetic resonance imaging analysis.

Study Design: Preoperative magnetic resonance imaging was performed on 45 consecutive patients diagnosed with adolescent idiopathic scoliosis to evaluate the brain and spinal cord.

Objectives: To investigate the prevalence of spinal cord abnormalities in patients undergoing surgery for adolescent scoliosis.

Summary Of Background Data: A review of the literature indicates that the number of abnormalities of the brain stem and spinal cord reported with magnetic resonance imaging in patients with idiopathic scoliosis is increasing.

End-result of routine ultrasound screening for congenital anomalies: the Belgian Multicentric Study 1984-92.

Five ultrasound laboratories from Obstetrics and Gynecology departments of Belgian university hospitals or affiliated institutions conducted a prospective study from 1984 to 1992 in which the results of prenatal ultrasound examinations were compared to examination reports of the neonates. The results of the period 1984-89 (PI) have been published previously, and those of the period 1990-92 (PII) are presented here. Some very minor congenital anomalies, as listed and defined in the EUROCAT Register, were excluded.

Sensitivity and specificity of routine antenatal screening for congenital anomalies by ultrasound: the Belgian Multicentric Study.

United States and European consensus views differ on the place of routine ultrasound scans during pregnancy and the validity of such scans as screening tests for fetal malformations in the general population is still under debate. Four ultrasound laboratories from Obstetric and Gynecology departments of Belgian University hospitals and affiliated hospitals have conducted a prospective study from 1984 to 1989 to compare the anomalies discovered in ultrasonic screening of the fetus with the anomalies of the neonates. Of 16,370 pregnant women at normal risk for congenital anomalies attending the antenatal clinics of these hospitals, 16,072 have had at least one ultrasound screening for congenital anomalies (98.

Pneumocephalus secondary to a high-pressure water injury to the nose.

We report a case of pneumocephalus following a water jet injury to the nose incurred during a water-skiing fall. Pneumocephalus due to this type of injury has not been previously reported, to our knowledge. Since this unusual injury may be associated with serious complications, it must be promptly recognized and treated.

An ALARA approach to the radiological control of foodstuffs following an accidental release.

This article presents a methodology based on two complementary approaches, thus allowing a selection of maximal concentration in foodstuffs for determining appropriate countermeasures. The first approach is based on a minimal and maximal per capita intervention level and takes into account the annual intake of each product. The second one is based on a cost-benefit analysis, comparing the advantages of a countermeasure concerning those products presenting a contamination higher than a given maximal concentration (in terms of reduction of cost of the detriment associated with the risk), with its drawbacks (in terms of cost of the products) in order to select the "ALARA" maximal concentration.