The state vector representing a quantum system acquires a phase factor following an adiabatic evolution along a closed trajectory in phase space. This is the traditional example of a geometric phase, ...or Pancharatnam–Berry phase, a concept that has now been generalized beyond cyclic adiabatic evolutions to include generalized quantum measurements, and that has been experimentally measured in a variety of physical systems. However, a clear description of the relationship between the emergence of a geometric phase and the effects of a series of generalized quantum measurements on a quantum system has not yet been provided. Here we report that a sequence of weak measurements with continuously variable measurement strengths in a quantum optics experiment conclusively reveals that the quantum measurement back-action is the source of the geometric phase—that is, the stronger a quantum measurement, the larger the accumulated geometric phase. We furthermore find that in the limit of strong (projective) measurement there is a direct connection between the geometric phase and the sequential weak value, ordinarily associated with a series of weak quantum measurements.Following a closed evolution in the Hilbert space, the state vector of a quantum system accumulates a geometric phase factor. A series of weak measurements reveal the origin of this in the back-action of any quantum measurement.
Background
Diagnostic performance based on x‐ray breast imaging is subject to breast density. Although digital breast tomosynthesis (DBT) is reported to outperform conventional mammography in denser ...breasts, mass detection and malignancy characterization are often considered challenging yet.
Purpose
As an improved diagnostic solution to the dense breast cases, we propose a dual‐energy DBT imaging technique that enables breast compositional imaging at comparable scanning time and patient dose compared to the conventional single‐energy DBT.
Methods
The proposed dual‐energy DBT acquires projection data by alternating two different energy spectra. Then, we synthesize unmeasured projection data using a deep neural network that exploits the measured projection data and adjacent projection data obtained under the other x‐ray energy spectrum. For material decomposition, we estimate partial path lengths of an x‐ray through water, lipid, and protein from the measured and the synthesized projection data with the object thickness information. After material decomposition in the projection domain, we reconstruct material‐selective DBT images. The deep neural network is trained with the numerical breast phantoms. A pork meat phantom is scanned with a prototype dual‐energy DBT system to demonstrate the feasibility of the proposed imaging method.
Results
The developed deep neural network successfully synthesized missing projections. Material‐selective images reconstructed from the synthesized data present comparable compositional contrast of the cancerous masses compared with those from the fully measured data.
Conclusions
The proposed dual‐energy DBT scheme is expected to substantially contribute to enhancing mass malignancy detection accuracy particularly in dense breasts.
The presence of two red clumps (RCs) in high-latitude fields of the Milky Way bulge is interpreted as evidence for an X-shaped structure originated from the bar instability. Here we show, however, ...that this double RC phenomenon is more likely to be another manifestation of multiple populations observed in globular clusters (GCs) in the metal-rich regime. As in the bulge GC Terzan 5, the helium enhanced second-generation stars in the classical bulge component of the Milky Way are placed on the bright RC, which is about 0.5 mag brighter than the normal RC originated from the first-generation stars, producing the observed double RC. In a composite bulge, where a classical bulge can coexist with a boxy pseudo bulge, our models can also reproduce key observations, such as the dependence of the double RC feature on metallicity and Galactic latitude and longitude. If confirmed by Gaia trigonometric parallax distances, this would indicate that the Milky Way bar is not sufficiently buckled to form the X-shaped structure in the bulge, and suggest that the early-type galaxies would be similarly prevailed by super-helium-rich subpopulation.
Objectives
To compare the diagnostic performance and interpretation time of digital breast tomosynthesis (DBT) for both novice and experienced readers with and without using a computer-aided ...detection (CAD) system for concurrent read.
Methods
CAD system was developed for concurrent read in DBT interpretation. In this observer performance study, we used an enriched sample of 100 DBT cases including 70 with and 30 without breast cancers. Image interpretation was performed by four radiologists with different experience levels (two experienced and two novice). Each reader completed two reading sessions (at a minimum 2-month interval), once with and once without CAD. Three different rating scales were used to record each reader’s interpretation. Reader performance with and without CAD was reported and compared for each radiologist. Reading time for each case was also recorded.
Results
Average area under the receiver operating characteristic curve values for BI-RADS scale on using CAD were 0.778 and 0.776 without using CAD, demonstrating no statistically significant differences. Results were consistent when the probability of malignancy and percentage probability of malignancy scales were used. Reading times per case were 72.07 s and 62.03 s (SD, 37.54 s vs 34.38 s) without and with CAD, respectively. The average difference in reading time on using CAD was a statistically significant decrease of 10.04 ± 1.85 s, providing 14% decrease in time. The time-reducing effect was consistently observed in both novice and experienced readers.
Conclusion
DBT combined with CAD reduced interpretation time without diagnostic performance loss to novice and experienced readers.
Key Points
• The use of a concurrent DBT-CAD system shortened interpretation time.
• The shortened interpretation time with DBT-CAD did not come at a cost to diagnostic performance to novice or experienced readers.
• The concurrent DBT-CAD system improved the efficiency of DBT interpretation.
Abstract
We performed low-resolution spectroscopy for the red giant branch stars in an intriguing globular cluster (GC) NGC 2808, which hosts subpopulations with extreme helium and light-element ...abundances. In order to trace N, C, and Ca abundance differences among subpopulations, we measured CN, CH, and Ca
ii
H&K spectral indices, respectively. We identified four subpopulations (G1, G2, G3, and G4) from CN and CH strength, with CN-weak/CH-strong G1, CN-intermediate/CH-strong G2, CN-strong/CH-intermediate G3, and CN-strong/CH-weak G4. Compared to Na/O from high-resolution spectroscopy, we show that CN index can more clearly separate G1 and G2. Since CN traces N abundance in a GC, it implies that G1 and G2 would show a larger difference in N/Fe compared to Na/Fe, as predicted by chemical evolution models. Later generation stars G3 and G4, however, are better separated with high-resolution spectroscopy. We also found that G4 shows a stronger Ca
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H&K line strength compared to that of G1, but we suspect this to be a result of unusually strong He enhancement and/or Mg depletion in G4 of this GC. This work illustrates that combining low- and high-resolution spectroscopic studies can improve the separation of subpopulations in GCs.
Working together: A “core–satellite” hybrid nanoparticle probe provides highly improved fluorescence and magnetic resonance (MR) imaging capabilities through synergistic enhancement of its respective ...components. These hybrid nanoprobes can be used for dual‐modal fluorescence and MR imaging of neuroblastoma with expressed polysialic acids.
•An 4D printed SMC actuator was fabricated using SMA and SMP with a FDM 3D printer.•A volume fraction of SMA:SMP of 1:5 showed the largest length change of 8 mm, and the most rapid response time of 4 ...s.•The reversible actuator mechanism explains the SMC actuation via each shape memory effect.•SMC showed potential application for stents and valve controllers via 3D printing technology to achieve customized designs.
A fused deposition modeling (FDM) tool was used to fabricate a shape memory composite (SMC) that combined a shape memory alloy (SMA) with a shape memory polymer (SMP). The SMA caused a shape memory effect due to a phase change between martensite and austenite phases, in turn due to a temperature change. Also, the SMP had a shape memory effect caused by changes in the proportions of hard and soft segments near the glass transition temperature (Tg). Usually, common SMAs and SMPs are not reversible, so these materials do not go back to their original shapes once they are deformed. In this study, we fabricated 4D printing actuator via reversible SMC actuations using 3D printing technology. Nylon 12 was used as the 3D printing material in filament form. Moreover, the volume fraction of SMA to SMP was varied to find the optimum ratio for good operation cycles. A volume fraction of SMA:SMP of 1:5 showed the largest length change, of 8 mm, and the most rapid response time, of 4 s in overall dimension of 140mm×10mm×1mm (length×width×thickness).Thus, the SMC showed promising results for the application of stents and valve controllers that could be manufactured by 3D printing technology.
Optimal interfaces play an important role in determining the efficiency of perovskite solar cells. Despite nickel oxide is a promising hole transport material in perovskite solar cells, electrical ...conductivity and surface properties of pristine nickel oxide are not satisfactory for achieving high efficiency perovskite solar cells. Here, we demonstrate that cobalt doping significantly improves not only the electrical conductivity but also the interfaces of nickel oxide hole transport layer. As a result, the hole extraction, transport and collection properties are significantly improved in the device using cobalt-doped nickel oxide as a hole transport layer. Also, it reveals that cobalt-doped nickel oxide reduces the trap-sites of interfaces of perovskite/hole transport layer, leading to suppressed charge recombination in the devices. As a result, the devices using cobalt-doped nickel oxide achieve as high as 17.52% without severe hysteresis, which is attributed to better band alignment, superior hole extraction and decreased resistance, as compared to pristine nickel oxide-based devices.
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•Co-doping of NiOX has been studied systematically to be used in perovskite solar cells.•Co-doped NiOX improved the optoelectronic properties of NiOX for hole transport layer.•Co-doped NiOX improved the efficiency of the solar cells from 13.96% to 17.52%.
Optimal interface of planar heterojunction perovskite solar cells determines efficient charge transport and collection for achieving high power conversion efficiency. Nickel oxide (NiOX) is one of ...the most well-known hole transport materials for perovskite solar cells because of its wide band gap, p-type transport characteristic, good chemical stability and high optical transparency. However, pristine NiOX possesses unsatisfactory electrical properties such as high surface trap density or low electrical conductivity which could deteriorate the device performance. We thus adopted Zn as a dopant to employ the Zn-doped NiOX as a hole transport layer in the planar heterojunction PSCs as considering that not only Zn has a similar atomic size with Ni but also Zn forms highly crystalline oxide materials. As a result, 5% Zn-doped devices achieved a power conversion efficiency up to 13.72% with improvements of a VOC by 4.0%, a JSC by 16.7% and a fill factor by 8.9% as compared to the un-doped NiOX counterpart.
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•Sol-gel driven Zn-doped NiOx has been demonstrated.•Zn-doped NiOx effectively improves interfaces of the perovskite solar cells.•Zn-doped NiOX raised the device efficiency of perovskite solar cells from 10.43% to 13.72%.
Melatonin, a pineal hormone that modulates circadian rhythms, sleep, and neurotransmitters, is widely used to treat sleep disorders. However, there are limited studies on the safety of melatonin. ...Therefore, we aimed to present the overall patterns of adverse events (AEs) following melatonin administration and identify potential safety signals associated with melatonin. Using VigiBase, a global individual case safety report (ICSRs) database managed by the World Health Organization (WHO), we conducted a retrospective, observational, pharmacovigilance study of melatonin between January 1996 and September 2022. Disproportionality analysis was conducted using two comparator settings: all other drugs and other sleep medications. We used multivariable logistic regression to estimate reporting odds ratios (RORs) with 95% confidence intervals (CIs) to compare the frequencies of AEs reporting between melatonin and each comparator setting. Furthermore, we assessed adverse events of special interests (AESIs) that could potentially be associated with melatonin. Signals were identified when the following criteria were met: cases ≥3, x2 ≥ 4, IC025 ≥ 0, and the lower end of the 95% CI of ROR > 2. These signals were then compared with the AE information on the drug labels provided by regulatory bodies. A total of 35 479 AE reports associated with melatonin were identified, with a higher proportion of reports from females (57.1%) and individuals aged 45–64 years (20.8%). We identified 21 AEs that were commonly detected as safety signals in the disproportionality analyses, including tic, educational problems, disturbance in social behavior, body temperature fluctuation, and growth retardation. In AESI analyses, accidents and injuries (adjusted ROR 2.97; 95% CI, 2.80–3.16), fall (2.24; 2.12–2.37), nightmare (4.90; 4.37–5.49), and abnormal dreams (3.68; 3.19–4.25) were detected as a signal of melatonin when compared to all other drugs, whereas those signals were not detected when compared to other sleep medications. In this pharmacovigilance study, exogenous melatonin showed safety profiles comparable to other sleep medications. However, several unexpected potential safety signals were identified, underscoring the need for further investigation at the population level.
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