Precision Mass Measurement of the Proton Dripline Halo Candidate

We report the first mass measurement of the proton-halo candidate ^{22}Al performed with the low energy beam ion trap facility's 9.4 T Penning trap mass spectrometer at facility for rare isotope beams. This measurement completes the mass information for the lightest remaining proton-dripline nucleus achievable with Penning traps. ^{22}Al has been the subject of recent interest regarding a possible halo structure from the observation of an exceptionally large isospin asymmetry [J. Lee et al., Large isospin asymmetry in Si22/O22 Mirror Gamow-Teller transitions reveals the halo structure of ^{22}Al, Phys. Rev. Lett. 125, 192503 (2020).PRLTAO0031-900710.1103/PhysRevLett.125.192503]. The measured mass excess value of ME=18 092.5(3) keV, corresponding to an exceptionally small proton separation energy of S_{p}=100.4(8) keV, is compatible with the suggested halo structure. Our result agrees well with predictions from sd-shell USD Hamiltonians. While USD Hamiltonians predict deformation in the ^{22}Al ground state with minimal 1s_{1/2} occupation in the proton shell, a particle-plus-rotor model in the continuum suggests that a proton halo could form at large quadrupole deformation. These results emphasize the need for a charge radius measurement to conclusively determine the halo nature.

Erratum: High-Precision Mass Measurement of

This corrects the article DOI: 10.1103/PhysRevLett.120.032701.

High-Precision Mass Measurement of

We report the mass measurement of ^{56}Cu, using the LEBIT 9.4 T Penning trap mass spectrometer at the National Superconducting Cyclotron Laboratory at Michigan State University. The mass of ^{56}Cu is critical for constraining the reaction rates of the ^{55}Ni(p,γ) ^{56}Cu(p,γ) ^{57}Zn(ß^{+}) ^{57}Cu bypass around the ^{56}Ni waiting point. Previous recommended mass excess values have disagreed by several hundred keV. Our new value, ME=-38626.7(7.1) keV, is a factor of 30 more precise than the extrapolated value suggested in the 2012 atomic mass evaluation [Chin. Phys. C 36, 1603 (2012)CPCHCQ1674-113710.1088/1674-1137/36/12/003], and more than a factor of 12 more precise than values calculated using local mass extrapolations, while agreeing with the newest 2016 atomic mass evaluation value [Chin. Phys. C 41, 030003 (2017)CPCHCQ1674-113710.1088/1674-1137/41/3/030003]. The new experimental average, using our new mass and the value from AME2016, is used to calculate the astrophysical ^{55}Ni(p,γ) and ^{56}Cu(p,γ) forward and reverse rates and perform reaction network calculations of the rp process. These show that the rp-process flow redirects around the ^{56}Ni waiting point through the ^{55}Ni(p,γ) route, allowing it to proceed to higher masses more quickly and resulting in a reduction in ashes around this waiting point and an enhancement to higher-mass ashes.

High Precision Determination of the ß Decay Q(EC) Value of (11)C and Implications on the Tests of the Standard Model.

We report the determination of the Q(EC) value of the mirror transition of (11)C by measuring the atomic masses of (11)C and (11)B using Penning trap mass spectrometry. More than an order of magnitude improvement in precision is achieved as compared to the 2012 Atomic Mass Evaluation (Ame2012) [Chin. Phys. C 36, 1603 (2012)]. This leads to a factor of 3 improvement in the calculated Ft value. Using the new value, Q(EC)=1981.690(61) keV, the uncertainty on Ft is no longer dominated by the uncertainty on the Q(EC) value. Based on this measurement, we provide an updated estimate of the Gamow-Teller to Fermi mixing ratio and standard model values of the correlation coefficients.

First Direct Determination of the Superallowed ß-Decay QEC Value for (14)O.

We report the first direct measurement of the (14)O superallowed Fermi ß-decay QEC value, the last of the so-called "traditional nine" superallowed Fermi ß decays to be measured with Penning trap mass spectrometry. (14)O, along with the other low-Z superallowed ß emitter, (10)C, is crucial for setting limits on the existence of possible scalar currents. The new ground state QEC value, 5144.364(25) keV, when combined with the energy of the 0(+) daughter state, Ex(0(+))=2312.798(11) keV [F. Ajzenberg-Selove, Nucl. Phys. A523, 1 (1991)], provides a new determination of the superallowed ß-decay QEC value, QEC(sa)=2831.566(28) keV, with an order of magnitude improvement in precision, and a similar improvement to the calculated statistical rate function f. This is used to calculate an improved Ft value of 3073.8(2.8) s.

Quantification and purification of isotopic contamination at the ReAccelerator of the Facility for Rare Isotope Beams.

At the ReAccelerator within the Facility for Rare Isotope Beams, a combination of an interchangeable aluminum foil and a silicon detector was developed to quantify isobaric contamination in rare isotope beams. The device is simple to operate and is now used routinely. In this article, we describe the system and show an application of the device to determine the level of contamination of an Si-32 rare isotope beam by stable S-32. In addition, we describe how the new diagnostic device helped confirm an enhancement of the beam purity prior to beam delivery to experiments.

Direct mass measurements of 19B, 22C, 29F, 31Ne, 34Na and other light exotic nuclei.

We report on direct time-of-flight based mass measurements of 16 light neutron-rich nuclei. These include the first determination of the masses of the Borromean drip-line nuclei (19)B, (22)C, and (29)F as well as that of (34)Na. In addition, the most precise determinations to date for (23)N and (31)Ne are reported. Coupled with recent interaction cross-section measurements, the present results support the occurrence of a two-neutron halo in (22)C, with a dominant ν2s(1/2)(2) configuration, and a single-neutron halo in (31)Ne with the valence neutron occupying predominantly the 2p(3/2) orbital. Despite a very low two-neutron separation energy the development of a halo in (19)B is hindered by the 1d(5/2)(2) character of the valence neutrons.

Development of a 1+/N+ setup for the production of multicharged radioactive alkali ions in SPIRAL.

In the framework of the production of radioactive ion beams by the isotope separator online method, a new system has been developed at GANIL/SPIRAL I to produce multicharged alkali ions. The principle, referred to as the "direct 1+/N+ method," consists of a surface ionization source associated with a multicharged electron-cyclotron-resonance ion source without an intermediate mass separator. This new system has been tested online using a (48)Ca primary beam at 60.3 A MeV. The experimental evidence of the direct 1+/N+ process has been obtained for a potential difference between the two sources of 11 V and with a 1+/N+ charge breeding efficiency of 0.04% for (47)K(5+). This value is significantly lower than the value of 6% obtained for stable K ions with the standard 1+/N+ method. A possible explanation is given in the text.

Measuring the difference in nuclear charge radius of Xe isotopes by EUV spectroscopy of highly charged Na-like ions.

The difference in the mean-square nuclear charge radius of xenon isotopes was measured utilizing a method based on extreme ultraviolet spectroscopy of highly charged Na-like ions. The isotope shift of the Na-like D1 (3s 2 S 1/2 - 3p 2 P 1/2) transition between the 124Xe and 136Xe isotopes was experimentally determined using the electron-beam ion-trap facility at the National Institute of Standards and Technology. The mass-shift and the field-shift coefficients were calculated with enhanced precision by the relativistic many-body perturbation theory and multiconfiguration Dirac-Hartree-Fock method. The mean-square nuclear charge radius difference was found to be δ〈r 2〉136,124 = 0.269(42) fm2. Our result has smaller uncertainty than previous experimental results and agrees with the literature values.

Simultaneous spectrophotometric determination in solid phase of aspirin and its impurity salicylic acid in pharmaceutical formulations.

We report the simultaneous determination of aspirin and its hydrolysis product, salicylic acid, in solid phase by fluorescence spectrophotometry. Aspirin is often the most labile component in a combination-type analgesic compound. Therefore, its stability is often the initial concern in any formulation-screening program. Preliminary screening of a large number of potential formulations can be arduous, because most current methods of analysis generally consist of several steps: extractions or column separations followed by UV, colorimetric, or gas-liquid chromatographic assays. The method proposed here is quite suited to large numbers of assays because it is not time consuming, it is straightforward, and it is not subject to interference from the substances present in the pharmaceutical formulations. In addition, the method is nondestructive, not dependent on the sampling procedure, and, above all, quite sensitive.

Variable pH kinetics: an easy determination of pH-rate profile.

The complete pH-rate profile of the hydrolysis reaction of aspirin, requiring many experiments in the past, was obtained by a single variable-parameter kinetic experiment carried out by varying the hydrogen ion concentration. The experiment was carried out spectrophotometrically, reading automatically absorbance, pH, and temperature inside the reaction vessel. The results obtained by the fast processing of the kinetic profile are identical to those obtained under the same conditions but using traditional constant-pH kinetic runs. This method provides the possibility of reducing the amount of time and chemicals usually spent in collecting kinetic data in such mechanistic studies by nearly two orders of magnitude.

Hydrolysis of aspirin studied by spectrophotometric and fluorometric variable-temperature kinetics.

Pseudo-first-order rate constants for the hydrolysis of acetylsalicylic acid as a function of temperature have been obtained by variable-temperature kinetic experiments. A method, based on a generalization of non-isothermal analysis, has been used that takes advantage of the capabilities of modern data collection and processing systems. Both spectrophotometric and, for the first time under non-isothermal conditions, fluorometric measurements have been carried out. The results obtained are identical to those obtained under the same conditions but using traditional constant-temperature kinetic runs. This provides the possibility of reducing the amounts of time and chemicals usually spent in collecting kinetic data in mechanistic studies in solution by an order of magnitude.

Stability study of piroxicam and cinnoxicam in solid pharmaceuticals.

The pseudo-first order rate constant for the hydrolysis of cinnoxicam as a function of temperature was obtained by variable-temperature kinetic experiments. The method used is on a generalization of non-isothermal analysis, and takes advantage of the capabilities of modern data collection and processing systems. A spectrophotometric method under non isothermal conditions was carried out. The results obtained are identical to those obtained under the same conditions by using traditional constant-temperature kinetic runs. This provides the possibility of reducing the amount of time spent and chemicals usually used in collecting kinetic data in mechanistic studies in solution by an order of magnitude.

Time-resolved fluorescence. An approach in protein analysis.

This paper deal with the spectroscopic analysis of proteins, i.e., human serum albumin (HSA) and bovine serum albumin (BSA). These two proteins present very similar UV absorption and fluorescence spectra. The UV-spectra of both proteins result from the sum of the absorption spectra of the aromatic amino acid, mainly tryptophan and tyrosine, present in the biological molecules. On the contrary, the fluorescence HSA and BSA spectra are not the sum of the emission fluorescence spectra of tyrosine and tryptophan, but they are mainly constituted by the tryptophan fluorescence with a poor contribution arising from tyrosine. This fact may be due to inter- and intramolecular quenching phenomena. Significant difference were recorder in the life time fluorescence decay of HSA and BSA, which showed tau values of 2.3 and 4.5 nanoseconds, respectively. The time-resolved fluorescence spectroscopy was performed with an experimental apparatus assembled in our laboratories, which is able of measuring the fluorescence decay in the range 2 x 10(-10)-2 x 10(-8) sec.

Fatty acid profiles in pigmented and non-pigmented strains of S. marcescens.

Wild, pigmented strains of Serratia marcescens and their non-pigmented mutants were compared on the basis of fatty acid profiles and lipid content. Classic biochemical tests show only minor differences, as well as fatty acid ratio C18:C16. The total amount of lipid synthesized and the saturated/unsaturated fatty acids ratio disclose a sharp total lipid reduction and a high percentage of unsaturated fatty acids in the pigmented strains, placing them in separated clusters compared with the nonpigmented mutants. It is hypothesized that the synthesis of the polyacetate required for the completion of the prodigiosin molecule may result in waste of methyl groups and thus affect the total amount of lipids.

High-performance liquid chromatography and diffuse reflectance spectroscopy of flavonoids in Crataegus oxyacantha L. III--Analysis of 2-phenyl-chroman derivatives and caffeic acid.

High-performance liquid chromatographic (HPLC) and diffuse infrared reflectance spectroscopic techniques for qualitative and quantitative analysis of naturally occurring phenolic compounds in Crataegus oxyacantha L. have been applied. (+)-Catechin, (-)-epicatechin and a phenolic acid, the caffeic acid, were investigated in various extractives of Crataegus oxyacantha L. The reversed-phase chromatographic separation was achieved by a combination of isocratic and gradient elution.

Dietary compliance in screening-detected coeliac disease adolescents.

In 1992-94 we screened 6315 students for coeliac disease (CD) by testing antigliadin antibodies (AGA) as the first-level investigation. We found 28 biopsy-proven coeliac patients who were invited to start the gluten-free diet (GFD). The aim of this study was a clinical and laboratory follow-up in these screening-detected coeliac adolescents. Patients were 17 females and 11 males with a mean age at diagnosis of 12.8 +/- 1 years (range 11-4). Mean follow-up duration time was 23 +/- 7 months (range 9-37). Twenty-three of the 28 screening-detected coeliac patients came to the control visit, 3 refused the follow-up and 2 subjects were not found. Twelve patients (52.2%) stated that they never ate any gluten-containing food, while 11 of them (47.8%) reported occasional transgressions to the diet. GFD acceptance was reported as good (n = 6), moderate (n = 11) or low (n = 6). After starting the GFD, signs of improvement were seen in most patients, such as weight gain, increased height velocity and increased feeling of well-being. AGA (both IgG and IgA classes) and antiendomysium antibodies (AEA) were normal in 19 subjects, 2 cases had IgG-AGA and AEA positivity, 1 patient showed abnormal AGA and AEA levels, while isolated IgA-AGA positivity persisted in 1 case. This study shows that even silent CD cases can clinically benefit from the GFD. The consequences of occasional transgressions to the GFD remain unclear.

[Thermal water of Alì Terme, Italy]. / Alì terme e le sue acque termali.

In this paper the history of the thermal water of Alì Terme (Sicily-Italy) and their beneficial effects are reported. Chemical and bacteriological investigations have been conducted for assay of thermophiles sulphur bacteria. As regards the chemical characteristics, traditional investigations have been carried out together with determination of H2S.

Release from transdermal delivery systems. Application of a new non isothermic method to Trans-Ver-Sal patches.

In this paper a new non isothermic method for the determination of the release drug rate constant (k) from a transdermal delivery system is proposed. The new method was applied to transdermal patches Trans-Ver-Sal. The results obtained prove to be able to release salicylic acid of transdermal system and the effectiveness of the new method propose.

Fast rolitetracycline stability determination by spectrophotometer variable-temperature kinetic experiments.

The pseudo-first order rate constant for the hydrolysis of rolitetracycline as a function of temperature was obtained by performing variable-temperature kinetic experiments. The results are in agreement with those obtained at constant-parameter kinetics but saving experimental time and chemicals.