Accurate Determination of Blackbody Radiation Shifts in a Strontium Molecular Lattice Clock.

Molecular lattice clocks enable the search for new physics, such as fifth forces or temporal variations of fundamental constants, in a manner complementary to atomic clocks. Blackbody radiation (BBR) is a major contributor to the systematic error budget of conventional atomic clocks and is notoriously difficult to characterize and control. Here, we combine infrared Stark-shift spectroscopy in a molecular lattice clock and modern quantum chemistry methods to characterize the polarizabilities of the Sr_{2} molecule from dc to infrared. Using this description, we determine the static and dynamic blackbody radiation shifts for all possible vibrational clock transitions to the 10^{-16} level. This constitutes an important step toward millihertz-level molecular spectroscopy in Sr_{2} and provides a framework for evaluating BBR shifts in other homonuclear molecules.

Erratum: Publisher's Note: "Laser-induced electron diffraction of the ultrafast umbrella motion in ammonia" [Struct. Dyn. 8, 014301 (2021)].

[This corrects the article DOI: 10.1063/4.0000046.].

Laser-induced electron diffraction of the ultrafast umbrella motion in ammonia.

Visualizing molecular transformations in real-time requires a structural retrieval method with Ångström spatial and femtosecond temporal atomic resolution. Imaging of hydrogen-containing molecules additionally requires an imaging method sensitive to the atomic positions of hydrogen nuclei, with most methods possessing relatively low sensitivity to hydrogen scattering. Laser-induced electron diffraction (LIED) is a table-top technique that can image ultrafast structural changes of gas-phase polyatomic molecules with sub-Ångström and femtosecond spatiotemporal resolution together with relatively high sensitivity to hydrogen scattering. Here, we image the umbrella motion of an isolated ammonia molecule (NH3) following its strong-field ionization. Upon ionization of a neutral ammonia molecule, the ammonia cation (NH3 +) undergoes an ultrafast geometrical transformation from a pyramidal ( Φ HNH = 107 ° ) to planar ( Φ HNH = 120 ° ) structure in approximately 8 femtoseconds. Using LIED, we retrieve a near-planar ( Φ HNH = 117 ± 5 ° ) field-dressed NH3 + molecular structure 7.8 - 9.8 femtoseconds after ionization. Our measured field-dressed NH3 + structure is in excellent agreement with our calculated equilibrium field-dressed structure using quantum chemical ab initio calculations.

Theoretical study of the Coriolis effect in LiNa, LiK, and LiRb molecules.

The non-adiabatic electronic matrix elements, LΠΣ(R), that arise from the spin-conserving electron-rotational interactions between all mΣ+ and mΠ states, where multiplicity m = 1, 3, converging to the lowest three dissociation limits of Li-containing alkali diatomics, LiM (M = Na, K, Rb), were calculated ab initio up to large internuclear distances, R. The required electronic wavefunctions were obtained within the framework of the multi-reference configuration interaction treatment of the two-valence-electron problem constructed using small-core scalar-relativistic effective core potentials and l-independent core-polarization potentials. A least squares analysis of the ab initio functions at large internuclear distances in conjunction with long-range perturbation theory (LRPT) revealed three different asymptotic behaviors of the LΠΣ(R → +∞)-functions: const. + ß[n]/Rn, characterized by n = -1, 3 and 6. The asymptotic coefficients ß[n], extracted from the point-wise ab initio data, were found to be in agreement with their LRPT counterparts, which were evaluated analytically using the relevant atomic parameters. The mass dependence of the LΠΣ matrix elements was investigated analytically and numerically. To confirm the reliability of the LΠΣ(R)-functions and interatomic potentials at small and intermediate distances, the empirical q-factors available for the D1Π-states of all LiM molecules studied were compared with their theoretical counterparts derived from the present ab initio data.

Transition Strength Measurements to Guide Magic Wavelength Selection in Optically Trapped Molecules.

Optical trapping of molecules with long coherence times is crucial for many protocols in quantum information and metrology. However, the factors that limit the lifetimes of the trapped molecules remain elusive and require improved understanding of the underlying molecular structure. Here we show that measurements of vibronic line strengths in weakly and deeply bound ^{88}Sr_{2} molecules, combined with ab initio calculations, allow for unambiguous identification of vibrational quantum numbers. This, in turn, enables the construction of refined excited potential energy curves, informing the selection of magic wavelengths that facilitate long vibrational coherence. We demonstrate Rabi oscillations between far-separated vibrational states that persist for nearly 100 ms.

Crossover from the Ultracold to the Quasiclassical Regime in State-Selected Photodissociation.

Processes that break molecular bonds are typically observed with molecules occupying a mixture of quantum states and successfully described with quasiclassical models, while a few studies have explored the distinctly quantum mechanical low-energy regime. Here, we use photodissociation of diatomic strontium molecules to demonstrate the crossover from the ultracold, quantum regime where photofragment angular distributions strongly depend on the kinetic energy to the quasiclassical regime. Using time-of-flight imaging for photodissociation channels with millikelvin reaction barriers, we explore photofragment energies in the 0.1-300 mK range experimentally and up to 3 K theoretically, and discuss the energy scale at which the crossover occurs. We find that the effects of quantum statistics can persist to high photodissociation energies.

Control of Ultracold Photodissociation with Magnetic Fields.

Photodissociation of a molecule produces a spatial distribution of photofragments determined by the molecular structure and the characteristics of the dissociating light. Performing this basic reaction at ultracold temperatures allows its quantum mechanical features to dominate. In this regime, weak applied fields can be used to control the reaction. Here, we photodissociate ultracold diatomic strontium in magnetic fields below 10 G and observe striking changes in photofragment angular distributions. The observations are in excellent agreement with a multichannel quantum chemistry model that includes nonadiabatic effects and predicts strong mixing of partial waves in the photofragment energy continuum. The experiment is enabled by precise quantum-state control of the molecules.

Photodissociation of ultracold diatomic strontium molecules with quantum state control.

Chemical reactions at ultracold temperatures are expected to be dominated by quantum mechanical effects. Although progress towards ultracold chemistry has been made through atomic photoassociation, Feshbach resonances and bimolecular collisions, these approaches have been limited by imperfect quantum state selectivity. In particular, attaining complete control of the ground or excited continuum quantum states has remained a challenge. Here we achieve this control using photodissociation, an approach that encodes a wealth of information in the angular distribution of outgoing fragments. By photodissociating ultracold (88)Sr2 molecules with full control of the low-energy continuum, we access the quantum regime of ultracold chemistry, observing resonant and nonresonant barrier tunnelling, matter-wave interference of reaction products and forbidden reaction pathways. Our results illustrate the failure of the traditional quasiclassical model of photodissociation and instead are accurately described by a quantum mechanical model. The experimental ability to produce well-defined quantum continuum states at low energies will enable high-precision studies of long-range molecular potentials for which accurate quantum chemistry models are unavailable, and may serve as a source of entangled states and coherent matter waves for a wide range of experiments in quantum optics.

Solitary fibrous mass of the omentum mimicking an ovarian tumor: case report.

There are some pelvic masses which are difficult to correctly classify as malignant or benign. The decision concerning method and choice of surgical intervention is not simple in this situation. Some tumors are extremely rare and need to be presented in the literature. The authors report a rare case of fibrous tumor of the omentum simulating a malignant ovarian tumor, which ultimately resulted to be a primary solitary fibrous tumor of the omentum. Ultrasound findings are mostly precise prognostic tools according ovarian masses. However, from time to time, Doppler blood flow examination may present false positive results.

Control of Optical Transitions with Magnetic Fields in Weakly Bound Molecules.

In weakly bound diatomic molecules, energy levels are closely spaced and thus more susceptible to mixing by magnetic fields than in the constituent atoms. We use this effect to control the strengths of forbidden optical transitions in (88)Sr2 over 5 orders of magnitude with modest fields by taking advantage of the intercombination-line threshold. The physics behind this remarkable tunability is accurately explained with both a simple model and quantum chemistry calculations, and suggests new possibilities for molecular clocks. We show how mixed quantization in an optical lattice can simplify molecular spectroscopy. Furthermore, our observation of formerly inaccessible f-parity excited states offers an avenue for improving theoretical models of divalent-atom dimers.

Nonadiabatic effects in ultracold molecules via anomalous linear and quadratic Zeeman shifts.

Anomalously large linear and quadratic Zeeman shifts are measured for weakly bound ultracold 88Sr2 molecules near the intercombination-line asymptote. Nonadiabatic Coriolis coupling and the nature of long-range molecular potentials explain how this effect arises and scales roughly cubically with the size of the molecule. The linear shifts yield nonadiabatic mixing angles of the molecular states. The quadratic shifts are sensitive to nearby opposite f-parity states and exhibit fourth-order corrections, providing a stringent test of a state-of-the-art ab initio model.

Difficulties in the diagnosis of ovarian carcinoma: case report of squamous cell ovarian carcinoma in a 26-year-old woman.

A 26-year-old woman who was admitted to the Gynecology Department with abdominal pain was later diagnosed with a multi-chamber tumor in the left ovary. Neoplastic markers were within normal limits. It was proposed that the patient should be operated on in order to remove the tumor, and a left salpingo-oophorectomy was performed. During the intraoperative histopathological examination, the tumor was described as being benign. However, in the final histopathological examination, a malignant neoplasm, a squamous cell carcinoma (G-2) of the ovary (pT1a), was found. It was decided that a hysterectomy and a right salpingo-oophorectomy should be performed. No other neoplastic foci were found in the postoperational material. The patient is currently undergoing periodic control examinations.

The role of endothelin-1 and its correlation with CA125 levels, grayscale ultrasonography and doppler findings in differential diagnoses of ovarian tumors.

PURPOSE OF INVESTIGATION: Assessment of endothelin-1 (ET-1) level for the differential diagnosis of ovarian tumors was performed. METHODS: Fifty-three women with ovarian tumors (12 malignant, 41 benign) treated at the Division of Gynecological Surgery, Poznan, Poland were analyzed. ET-1 serum levels were compared with CA125 and Doppler parameters (RI, PI, PSV). The differences were evaluated using the unpaired t-test with Welch's correction (p < 0.05). RESULTS: There was statistically significant difference in ET-1 levels between the ovarian cancer and benign tumor groups (3.130 pg/ml and 1.819 pg/ml, respectively). The ROC area for ET-1 and CA125 were 0.727 and 0.791, respectively. A negative linear correlation between the level of ET-1 and RI and a positive linear correlation between the level of ET-1 and PSV in the ovarian cancer group were found. CONCLUSION: ET-1 as a new biomarker for predicting ovarian cancer is not satisfying. A correlation between ET-1 levels and Doppler parameters is very interesting and its role in angiogenesis should be studied extensively.

Comparison of diagnostic usefulness of predictive models in preliminary differentiation of adnexal masses.

The purpose of this study was to compare prognostic models evaluating the probability of an ovarian cancer occurrence based on a number of clinical and ultrasonographic data in women with adnexal masses. A total of 686 women with adnexal masses underwent the examinations between 1994 and 2002. The recorded parameters included: age, menopausal status, body mass index, the grayscale and Doppler ultrasonographic examination, and selected markers concentration levels. In order to find the best combination of features, which significantly influences the probability of malignancy, stepwise logistic regression analysis, as well as artificial neural network, was used. The diagnostic efficiency of received models was estimated and compared using receiver-operating characteristics (ROC) curve. The results indicate that 431 and 255 patients had a benign and malignant ovarian tumor, respectively. Application of stepwise logistic regression analysis revealed statistically significant importance of eight features. The sensitivity and specificity for the received model were 65.71% and 77.59%, respectively. Three-layer perceptron network shows 13 features as significant predictors of malignancy. The network gave a sensitivity of 85.7% and specificity of 93.1%. Comparison of area under ROC curve for received models was 0.9679 vs 0.9716. Prognostic values of the analyzed neural model are not optimal but seem to surpass logistic regression model in terms of the predictive possibilities.

Using logistic regression analysis in preliminary differential diagnosis of adnexal masses.

The aim of our study was to generate predictive model, which would allow to estimate the influence of analyzed parameters on predictive accuracy of differential diagnosis of adnexal masses and to evaluate prospectively diagnostic efficacy of the statistic model in the new set of patients. A total of 686 women diagnosed and surgically treated in the Gynecological and Obstetrical Teaching Hospital of University of Medical Sciences in Poznan, Poland, were recruited into the study. Preoperative diagnostics included gynecological examination, ultrasonographic evaluation, tumor Doppler blood flow analysis, and serum levels of CA125 and TPS. In order to find the best combination of features and to calculate the individual probability of the malignancy, stepwise logistic regression analysis with quasi-Newton estimation was applied. The essential part of the best prognostic model, described by foregoing variables, is as follows: [z = -6.005 + 0.058 x age + 1.174 x septa + 1.317 x tumor localization + 1.185 x ascites + 2.28 x solid element + 2.429 x vessels localization -2.386 x PI + 0.084 x MEDV]. The highest sensitivity and specificity for the obtained model were 87.84% and 93.74%, respectively. Prognostic model, constructed with the use of logistic regression analysis, is characterized by higher sensitivity and specificity than individually applied diagnostic tests. Prospective evaluation of this model application in a larger group of patients with adnexal masses will enable precise assessment of its objective clinical usefulness.

Artificial neural network computer prediction of ovarian malignancy in women with adnexal masses.

OBJECTIVE: Assessment of the usefulness of a neural model to predict which ovarian tumors are malignant. METHOD: Age, menopausal status, body mass index, grayscale and Doppler ultrasonographic features, as well as levels of specific markers (CA 125, tissue polypeptide specific antigen) were examined in 686 women with adnexal masses. The probability of malignancy was calculated using an artificial neural network software and the diagnostic efficiency of the received model was estimated using a receiver-operating characteristics (ROC) curve. RESULT: Of the 686 women, 431 (62.8%) had a benign and 255 (37.2%) had a malignant ovarian tumor. The significant malignancy predictors are age, menopausal status, maximum tumor diameter, internal wall structure of tumor, presence of septa and/or solid elements, tumor location, location of vessels, and blood flow indexes. The best network provided 96.0% sensitivity and 97.7% specificity. The area under the curve for the received model was 0.9716. CONCLUSIONS: An artificial neural network model based on clinical and ultrasonographic data allows to calculate the probability of tumor malignancy.

An ultrasonographic morphological index for prediction of ovarian tumor malignancy.

PURPOSE OF INVESTIGATION: A newly created ultrasonographic scale called the Poznan index as well as scales already well known (introduced by Sassone, De Priest and Lerner) were compared in our group of patients. METHOD: A morphological index was based on seven sonographic ovarian tumor features. Examinations on 686 patients were evaluated. Comparison of prognostic values of the Poznan index with other applied morphological indices in our group of patients was based on the area under receiver operating characteristic (ROC) curves. RESULTS: The cut-off level of the new index is 8 points. The new morphological index has a specificity of 77.0%, and negative and positive predictive values of 90.7% and 69.1%, respectively. It has a sensitivity of 86.7% and accuracy of 80.6%. The Poznan index proved its usefulness and superiority (AU ROC = 0.89). CONCLUSION: Using this morphological index it is possible to make a precise prognosis of ovarian tumor malignancy. It also makes it possible to make the right decision concerning the manner of surgical treatment.

Bleeding from endometrial and vaginal malignant tumors treated with activated recombinant factor VII.

The authors report two cases of successful employment of human recombinant activated factor VII in gynecological oncological patients (endometrial cancer and vaginal sarcoma) without pre-existing coagulopathy. They conclude that recombinant factor VIIa may be an important and effective drug in severe bleeding in gynecological oncology.

Estimation of neovascularisation in hyperplasia and carcinoma of endometrium using a "power" angio-Doppler technique.

The aim of this study was to estimate neovascularisation in hyperplasia and carcinoma of the endometrium using a "power" angio-Doppler technique. One hundred and eighty-two postmenopausal patients with irregular bleeding from the sexual organs were investigated. Age of the patients ranged between 46 and 78 years. No neovascularisation in a control group of women with normal histopathological results of the endometrium was observed. The sensitivity of this method with reference to the diagnosis of hyperplasia and cancer of the endometrium was 12.2% and 81.2%, respectively. The specificity and positive prediction values were equal to 100% each in both pathologies. The values of the analysed flow indices in the neovascular arteries in endometrial cancer were significantly lower (p<0.05) (properly PI-0.92+/-0.12; RI-0.46+/-0.08) in comparison to the corresponding values in hyperplasia of the endometrium (PI-1.38+/-0.28 and RI-0.66+/-0.18). In conclusion, using a "power" angio-Doppler technique irregular vascularity of the endometrium in a group of patients with hyperplasia was observed in 12.2% of all patients and in 81.2% of those with cancer of the endometrium. The analysis of the values of the blood flow qualitative parameters in the neovascularisation areas in the endometrium at the significance level of PI < or = 1.0; RI < or = 0.5 and TAMV > 18.0 cm can help determine the essential element in the differential diagnosis of benign and malicious lesions. Transvaginal ultrasonography with a "power" angio-Doppler technique can be a valuable diagnostic method in hyperplasia and cancer of the endometrium, especially useful in the early stages of these pathologies.