A recent rejuvenation of experimental and theoretical interest in the physics of few-body systems has provided deep, fundamental insights into a broad range of problems. Few-body physics is a ...cross-cutting discipline not restricted to conventional subject areas such as nuclear physics or atomic or molecular physics. To a large degree, the recent explosion of interest in this subject has been sparked by dramatic enhancements of experimental capabilities in ultracold atomic systems over the past decade, which now permit atoms and molecules to be explored deep in the quantum mechanical limit with controllable two-body interactions. This control, typically enabled by magnetic or electromagnetically dressed Fano-Feshbach resonances, allows, in particular, access to the range of universal few-body physics, where two-body scattering lengths far exceed all other length scales in the problem. The Efimov effect, where three particles experiencing short-range interactions can counterintuitively exhibit an infinite number of bound or quasibound energy levels, is the most famous example of universality. Tremendous progress in the field of universal Efimov physics has taken off, driven particularly by a combination of experimental and theoretical studies in the past decade, and prior to the first observation in 2006, by an extensive set of theoretical studies dating back to 1970. Because experimental observations of Efimov physics have usually relied on resonances or interference phenomena in three-body recombination, this connects naturally with the processes of molecule formation in a low-temperature gas of atoms or nucleons, and more generally with N-body recombination processes. Some other topics not closely related to the Efimov effect are also reviewed in this article, including confinement-induced resonances for explorations of lower-dimensionality systems, and some chemically interesting systems with longer-range forces such as the ion-atom-atom recombination problem.
Optical cycling of AlF molecules Hofsäss, S; Doppelbauer, M; Wright, S C ...
New journal of physics,
07/2021, Letnik:
23, Številka:
7
Journal Article
Recenzirano
Odprti dostop
Abstract
Aluminium monofluoride (AlF) is a promising candidate for laser cooling and trapping at high densities. We show efficient production of AlF in a bright, pulsed cryogenic buffer gas beam, and ...demonstrate rapid optical cycling on the Q rotational lines of the
A
1
Π ↔
X
1
Σ
+
transition. We measure the brightness of the molecular beam to be >10
12
molecules per steradian per pulse in a single rotational state and present a new method to determine its velocity distribution in a single shot. The photon scattering rate of the optical cycling scheme is measured using three different methods, and is compared to theoretical predictions of the optical Bloch equations and a simplified rate equation model. Despite the large number of Zeeman sublevels (up to 216 for the Q(4) transition) involved, a high scattering rate of at least 17(2) × 10
6
s
−1
can be sustained using a single, fixed-frequency laser without the need to modulate the polarisation. We deflect the molecu-lar beam using the radiation pressure force and measure an acceleration of 8.7(1.5) × 10
5
m s
−2
. Losses from the optical cycle due to vibrational branching to
X
1
Σ
+
,
v
″ = 1 are addressed efficiently with a single repump laser. Further, we investigate two other loss channels, parity mixing by stray electric fields and photo-ionisation. The upper bounds for these effects are sufficiently low to allow loading into a magneto‐optical trap.
Abstract
Background
Uveal melanoma (UM) is the eye's most common primary malignancy and there are no effective therapies for disseminated disease. It is important to try to know the patient's ...prognosis. The aim of this study was to reflect genetic variants, studied using NGS, of a series of 69 cases of UM and its correlation with histopathology and clinical progression.
Methods
We performed targeted NGS using a 519‐gene panel.
Results
There were selected 28 different mutated genes, showing a total of 231 genetic variants that affected the function of the protein. The most common secondary mutations occurred in SF3B1 (in 26%), followed by BAP1 (in 23%), LRP1B (22%) and FGFR4 (20%). BAP1 mutation was associated with a greater likelihood of metastases and with greater presence of epithelioid cells. LRP1B was also associated with presence of epithelioid cells SF3B1 mutation was significantly associated with a spindle morphology. We found variants in the RAD51B, TOP2A, PTPRD, TSC2, DHX9, PDK1 and MTOR that have not been previously reported in consulted databases. The presence of a mutation in: CHEK2, DHX9 and PDK1 was associated with metastases.
Conclusions
BAP1 is the most solid biomarker of a poor prognosis in UM and mutations can be detected using NGS. SF3B1 is associated with the spindle cell subtype of UM, which gives it probably a favourable prognostic value. Our study suggests that mutations in DHX9 and PDK1 can have prognostic value. These potential biomarkers are related to the PI3K/AKT/mTOR pathway and makes them candidates for developing new directed therapies.
An organo-zeolite was prepared by loading hexadecyltrimethylammonium (HDTMA) onto clinoptilolite and was used to remove ceftriaxone sodium and paracetamol in aqueous solutions. Batch experiments were ...conducted to perform kinetics and sorption isotherms at 25 °C and 100 rpm. The results indicate that the equilibration times were 24 h for ceftriaxone sodium and 9 h for paracetamol. Furthermore, sorption capacities were 0.7288 and 0.0058 mg/g, respectively. The data were treatment with different models including pseudo first order, second order, and Elovich, the results suggested a chemical adsorption mechanism, and the adsorption equilibrium data for the two drugs show that they follow a linear trend, indicating a partitioning mechanism. Physicochemical properties such as solubility, log Kow, and pka play an important role in the adsorption process. Finally, the values obtained for zero charge point (ZPC) for zeolitic materials were 6.90, 6.94, and 6.90 for natural zeolite (ZN), sodium zeolite (ZNa), and zeolite modified surface at 30 mM HDTMA (ZMS-30), respectively.
Impurity physics is a traditional topic in condensed matter physics that nowadays is being explored in the field of ultracold gases. Among the different classes of impurities, we focus on charged ...impurities in an ultracold bath. When a single ion is brought in contact with an ultracold gas, it is subjected to different reactive processes that can be understood from a cold chemistry perspective. In this work, we present an outlook of approaches for the dynamics of a single ion in a bath of ultracold atoms or molecules, complementing the usual many-body approaches characteristic of impurity physics within condensed matter physics. In particular, we focus on the evolution of a charged impurity in different baths, including external time-dependent trapping potentials, and explore the effect of the external laser sources present in ion-neutral hybrid traps on the reaction probability and evolution of an impurity.
Metabolism of the carotenoids in humans is often reserved to bioconversion of provitamin A carotenoids in retinoids and oxidative/degradative products arising from enzymatic eccentric cleavage, ...yielding apo-carotenoids. Nevertheless, additional metabolic routes should be available, and some of the structures of those metabolites have only been anticipated. The identification of carotenoids and their metabolites is commonly performed by HPLC coupled to MS. The acquisition of MS data in different instrumental modes and hardware configurations allows the detailed structural description of the target compound. Indeed, the MS data of carotenoids and their metabolites available in literature could be collected in a database to automatically perform a screening of the theoretical MS data included in the database with the MS experimental values. This review describes the required fundamentals for a systematic pursuit of carotenoids and their metabolites. Highlights on the use of appropriate hyphenated HPLC-MS systems and the requirements for the identification are discussed, while the application of software tools to apply filtering rules and the implementation of post-processing workflow, which uses two orthogonal criteria for the identification from the mass spectra data, are described.
Display omitted
•Systematic high-throughput screening of carotenoids and their metabolites is described.•Analytical techniques are completed with software tools for automatic data processing.•Filtering rules are applied to accurate mass and isotopic pattern for identification.
To assess the impact of all-oral direct-acting antiviral agent (DAA) regimens on the risk of hepatocellular carcinoma (HCC) in HIV/HCV-coinfected patients with cirrhosis.
This was a multicentre ...prospective cohort study recruiting HIV/HCV-coinfected patients with a new diagnosis of compensated cirrhosis. Patients were followed up until HCC, death or the censoring date (March 2017). The primary endpoint was the emergence of HCC. The incidence rate (IR) (95% CI) of HCC in different groups was computed. Time-to-event analyses were performed to identify predictors of HCC emergence.
The study included 495 HIV/HCV-coinfected patients with cirrhosis. After a median (IQR) follow-up of 59 (27-84) months, 22 (4.4%; 95% CI 2.6-6.3) patients developed an HCC. The IR (95% CI) of HCC was 0.93 (0.06-1.42) per 100 person-years (PY). Three hundred and three (61%) patients achieved sustained virological response (SVR) during follow-up, 79 after interferon (IFN)-based regimens and 224 after an all-oral DAA regimen. The IR (95% CI) of HCC after all-oral DAA was 0.35 (0.14-0.85) per 100 PY whereas it was 1.79 (1.11-2.88) per 100 PY in the remaining cohort (P = 0.0005). When only patients with SVR were considered, the IR (95% CI) of HCC after all-oral DAA was 0.32 (0.12-0.86) whereas it was 0 per 100 PY among those with SVR after IFN-based therapies (P = 0.27). Achieving SVR with an all-oral DAA regimen during follow-up was independently associated with a lower risk of HCC emergence (subhazard ratio 0.264; 95% CI 0.070-0.991; P = 0.049).
SVR with all-oral DAA regimens reduces the risk of HCC in HIV/HCV-coinfected patients with compensated cirrhosis.
In this work, Fe
3
O
4
@ZnFe
2
O
4
core/shell nanoparticles were obtained by depositing ZnO by the wet chemistry method on the surface of Fe
3
O
4
nanoparticles seeds obtained by the chemical bath ...deposition method. Fe
3
O
4
and Fe
3
O
4
@ZnFe
2
O
4
were characterized by Field Emission Scanning Electron Microscopy, Energy Dispersive X-ray Spectrometry, Transmission Electron Microscopy, X-ray Diffraction, Ultraviolet–Visible Spectroscopy, Diffuse Reflectance, and Fourier Transformed Infrared Spectroscopy (FTIR). The Fe
3
O
4
@ZnFe
2
O
4
nanoparticles formed an urchin-like spheres morphology (corresponding to Fe
3
O
4
) with a homogeneous shell of ZnFe
2
O
4
. XRD analysis showed a magnetite crystal structure for Fe
3
O
4
and a franklinite (ZnFe
2
O
4
) crystal structure for the shell. Fe
3
O
4
@ZnFe
2
O
4
showed higher crystallinity when applying a heat treatment, showing a crystal size of 9.12 nm with heat treatment and 9.43 nm without heat treatment. The diffuse reflectance results suggested an indirect band gap of 1.85 eV for Fe
3
O
4
and two indirect band gaps of 1.85 eV and 2.54 eV for Fe
3
O
4
@ZnFe
2
O
4
. The FTIR results showed the effect of heat treatment on Fe
3
O
4
@ZnFe
2
O
4
core/shell nanoparticles. A simple method was used for the synthesis of Fe
3
O
4
@ZnFe
2
O
4
.
Three-body recombination, or ternary association, is a termolecular reaction in which three particles collide, forming a bound state between two, whereas the third escapes freely. Three-body ...recombination reactions play a significant role in many systems relevant to physics and chemistry. In particular, they are relevant in cold and ultracold chemistry, quantum gases, astrochemistry, atmospheric physics, physical chemistry, and plasma physics. As a result, three-body recombination has been the subject of extensive work during the last 50 years, although primarily from an experimental perspective. Indeed, a general theory for three-body recombination remains elusive despite the available experimental information. Our group recently developed a direct approach based on classical trajectory calculations in hyperspherical coordinates for three-body recombination to amend this situation, leading to a first principle explanation of ion-atom-atom and atom-atom-atom three-body recombination processes. This review aims to summarise our findings on three-body recombination reactions and identify the remaining challenges in the field.
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