Controlling Fragmentation of the Acetylene Cation in the Vacuum Ultraviolet via Transient Molecular Alignment

An open-loop control scheme of molecular fragmentation based on transient molecular alignment combined with single-photon ionization induced by a short-wavelength free electron laser (FEL) is demonstrated for the acetylene cation. Photoelectron spectra are recorded, complementing the ion yield measurements, to demonstrate that such control is the consequence of changes in the electronic response with molecular orientation relative to the ionizing field. We show that stable C₂H₂⁺ cations are mainly produced when the molecules are parallel or nearly parallel to the FEL polarization, while the hydrogen fragmentation channel (C₂H₂⁺ → C₂H⁺ + H) predominates when the molecule is perpendicular to that direction, thus allowing one to distinguish between the two photochemical processes. The experimental findings are supported by state-of-the art theoretical calculations.

Parental Knowledge on Prevention of SUID

Background

According to the 2018 America’s Health Ranking Annual Report, the U.S. infant mortality rate (IMR) was 5.9 deaths per 1,000 live infant births, which placed the U.S. at No. 33 out of 36 countries with the world’s largest economies in 2018. The IMR in Georgia has been on the rise since 2014. Even though there was a sharp decline in sudden unexpected/unexplained causes of death (SUID) beginning in 1990, the decrease has considerably slowed down since 1999. In 2017, the top ten leading causes of infant death were responsible for 67.8% of all infant deaths in the United States. Sudden Infant Death Syndrome (SIDS) and death from unintentional injuries were in third and fourth place. Therefore, the purpose of this research is to utilize qualitative research guided by the Socio-Ecological model to understand better how prepared first-time mothers are to take care of their infant upon hospital release.

Methods

An intensity sampling was utilized to recruit participants. The inclusion criteria for the participants included first-time mothers with children under one year of age, women, Georgia residents over 18 years of age, and English speaking. A semi-structured guide was based on research queries and the ideological concepts of the Socio-Ecological Model. For the qualitative data examination, the thematic analysis was performed. All the interviews were transcribed verbatim and coded by using the program NVivo 11.

Results

A total of 25 women participated in the study. We will finish the data analysis by the end of May, 2022. The results of this qualitative study will help to fully understand the knowledge, perceptions, skills, and confidence of mothers about infant care.

Conclusions

The study’s results will help develop an information guide on primary infant care. Besides, health professionals and community organizations can utilize the study results to determine the information and support needed for new mothers.

Key messages

• The results of this qualitative study will help to fully understand the knowledge, perceptions, skills, and confidence of mothers about infant care.

• This study’s results will help develop an information guide (electronic or/and printed) on primary infant care based on first-time mothers’ needs.

Efecto del ácido alfa lipoico sobre la peroxidación no enzimática en mitocondrias de corazón y cerebro de rata

El ácido alfa lipoico (aal) ha sido caracterizado como un antioxidante eficiente. Se ha propuesto como un agente terapéutico potencial en el tratamiento o prevención de diferentes alteraciones que pueden estar relacionadas con un desequilibrio del estado celular oxidoreductor. El objetivo de este trabajo fue analizar la sensibilidad a la peroxidación no enzimática (pne) (ascorbato-Fe++ dependiente) en mitocondrias de corazón y cerebro de ratas incubadas con una solución de aal. La pne fue evaluada por el método de quimioluminiscencia (ql). Cuando se compararon las muestras control (sin el agregado del ascorbato-Fe++) con las muestras ascorbato-Fe++ dependientes, se observó un incremento significativo en la emisión lumínica. Simultáneamente, se incubaron las mitocondrias de ambos órganos con diferentes concentraciones de aal (0,05, 0,15 y 0,25 mg/ml) observándose una protección diferencial. Las mitocondrias de cerebro de rata incubadas con dosis de 0,15 y 0,25 mg/ml de aal fueron protegidas de los efectos de la pne, mientras que, en las mitocondrias cardíacas, solo se observó protección con la dosis más alta de aal (0,25 mg/ml). El análisis de ql indicó que las mitocondrias de cerebro fueron protegidas de manera más eficiente que las mitocondrias de corazón de rata. En este último caso, será necesario probar nuevas dosis de aal para demostrar los efectos en estas membranas. En conclusión, aal actuó como un antioxidante protector de las membranas de ambos órganos contra el daño peroxidativo.

Attosecond timing of electron emission from a molecular shape resonance

Shape resonances in physics and chemistry arise from the spatial confinement of a particle by a potential barrier. In molecular photoionization, these barriers prevent the electron from escaping instantaneously, so that nuclei may move and modify the potential, thereby affecting the ionization process. By using an attosecond two-color interferometric approach in combination with high spectral resolution, we have captured the changes induced by the nuclear motion on the centrifugal barrier that sustains the well-known shape resonance in valence-ionized N2. We show that despite the nuclear motion altering the bond length by only 2%, which leads to tiny changes in the potential barrier, the corresponding change in the ionization time can be as large as 200 attoseconds. This result poses limits to the concept of instantaneous electronic transitions in molecules, which is at the basis of the Franck-Condon principle of molecular spectroscopy.

Charge migration in photo-ionized aromatic amino acids

Attosecond pump-probe spectroscopy is a unique tool for the direct observation of the light-activated electronic motion in molecules and it offers the possibility to capture the first instants of a chemical reaction. Recently, advances in attosecond technology allowed the charge migration processes to be revealed in biochemically relevant molecules. Although this purely electronic process might be key for a future chemistry at the electron time scale, the influence of this ultrafast charge flow on the reactivity of a molecule is still debated. In this work, we exploit extreme ultraviolet attosecond pulses to activate charge migration in two aromatic amino acids, namely phenylalanine and tryptophan. Advanced numerical calculations are performed to interpret the experimental data and to discuss the effects of the nuclear dynamics on the activated quantum coherences. By comparing the experimental results obtained in the two molecules, we show that the presence of different functional groups strongly affects the fragmentation pathways, as well as the charge rearrangement. The observed charge dynamics indeed present peculiar aspects, including characteristic periodicities and decoherence times. Numerical results indicate that, even for a very large molecule such as tryptophan, the quantum coherences can survive the nuclear dynamics for several femtoseconds. These results open new and important perspectives for a deeper understanding of the photo-induced charge dynamics, as a promising tool to control the reactivity of bio-relevant molecules via photo-excitation. This article is part of the theme issue 'Measurement of ultrafast electronic and structural dynamics with X-rays'.

Control of H_{2} Dissociative Ionization in the Nonlinear Regime Using Vacuum Ultraviolet Free-Electron Laser Pulses

The role of the nuclear degrees of freedom in nonlinear two-photon single ionization of H_{2} molecules interacting with short and intense vacuum ultraviolet pulses is investigated, both experimentally and theoretically, by selecting single resonant vibronic intermediate neutral states. This high selectivity relies on the narrow bandwidth and tunability of the pulses generated at the FERMI free-electron laser. A sustained enhancement of dissociative ionization, which even exceeds nondissociative ionization, is observed and controlled as one selects progressively higher vibronic states. With the help of ab initio calculations for increasing pulse durations, the photoelectron and ion energy spectra obtained with velocity map imaging allow us to identify new photoionization pathways. With pulses of the order of 100 fs, the experiment probes a timescale that lies between that of ultrafast dynamical processes and that of steady state excitations.

Autoimmune comorbidity in achalasia patients

BACKGROUND AND AIM

Idiopathic achalasia is a rare esophageal motor disorder. The disease state manifests local and systemic inflammation, and it appears that an autoimmune component and specific autoantibodies participate in the pathogenesis. The study aims to determine the prevalence of autoimmune and chronic inflammatory diseases in patients with achalasia and compare the results with those from patients with gastroesophageal reflux disease (GERD).

METHODS

It was a cross-sectional and included 114 patients with idiopathic achalasia and 114 age-matched and sex-matched control patients with GERD. Data on the presence of autoimmune and inflammatory diseases, the time of presentation, and any family history of autoimmune disease were obtained from the hospital's medical records.

RESULTS

Seventy three (64%) were female patients (mean age: 42.3 ± 15.5; median disease duration: 12 months). We identified the presence of autoimmune disease in 19 patients with achalasia (16.7%), hypothyroidism was the main diagnosis, and it was present in 52.6% of patients compared with 4.2% in controls. Thirteen of the 19 achalasia patients (68.4%) with autoimmune disease had history of familial autoimmunity. We identified 11 achalasia (9.6%) and 5 GERD patients (4.16%) with an inflammatory condition. Compared with the GERD, the achalasia group was 3.8 times more likely to have an autoimmune disease (95% CI: 1.47-9.83), 3.0 times more likely to have thyroidopathies (95% CI: 1.00-9.03), and 3.02 times more likely to suffer from any chronic inflammatory disease (95% CI: 1.65-6.20).

CONCLUSIONS

The non-negligible number of patients with autoimmune diseases identified among the patients with idiopathic achalasia supports the hypothesis that achalasia has an autoimmune component.

Imaging the square of the correlated two-electron wave function of a hydrogen molecule

The toolbox for imaging molecules is well-equipped today. Some techniques visualize the geometrical structure, others the electron density or electron orbitals. Molecules are many-body systems for which the correlation between the constituents is decisive and the spatial and the momentum distribution of one electron depends on those of the other electrons and the nuclei. Such correlations have escaped direct observation by imaging techniques so far. Here, we implement an imaging scheme which visualizes correlations between electrons by coincident detection of the reaction fragments after high energy photofragmentation. With this technique, we examine the H₂ two-electron wave function in which electron–electron correlation beyond the mean-field level is prominent. We visualize the dependence of the wave function on the internuclear distance. High energy photoelectrons are shown to be a powerful tool for molecular imaging. Our study paves the way for future time resolved correlation imaging at FELs and laser based X-ray sources.

Electron-electron correlation is a complex and interesting phenomenon that occurs in multi-electron systems. Here, the authors demonstrate the imaging of the correlated two-electron wave function in hydrogen molecule using the coincident detection of the electron and proton after the photoionization.

Proper Orthogonal Decomposition Methods for the Analysis of Real-Time Data: Exploring Peak Clustering in a Secondhand Smoke Exposure Intervention

This work explores a method for classifying peaks appearing within a data-intensive time-series. We summarize a case study from a clinical trial aimed at reducing secondhand smoke exposure via the installation of air particle monitors in households. Proper orthogonal decomposition (POD) in conjunction with a k-means clustering algorithm assigns each data peak to one of two clusters. Aversive feedback from the monitors increased the proportion of short-duration, attenuated peaks from 38.8% to 96.6%. For each cluster, a distribution of parameters from a physics-based model of airborne particles is estimated. Peaks generated from these distributions are correctly identified by POD/clustering with >60% accuracy.

Infrastructures, treatment modalities, and workload of radiation oncology departments in Spain with special attention to prostate cancer

AIM

The purpose of the study was to describe infrastructures, treatment modalities, and workload in radiation oncology (RO) in Spain, referred particularly to prostate cancer (PC).

METHODS

An epidemiologic, cross-sectional study was performed during 2008-2009. A study-specific questionnaire was sent to the 108 RO-registered departments.

RESULTS

One hundred and two departments answered the survey, and six were contacted by telephone. Centers operated 236 treatment units: 23 (9.7 %) cobalt machines, 37 (15.7 %) mono-energetic linear accelerators, and 176 (74.6 %) multi-energy linear accelerators. Sixty-one (56.4 %) and 33 (30.5 %) departments, respectively, reported intensity-modulated radiation therapy (IMRT) and image-guided RT (IGRT) capabilities; three-dimensional-conformal RT was used in 75.8 % of patients. Virtual simulators were present in 95 departments (88.0 %), 35 use conventional simulators. Fifty-one departments (47.2 %) have brachytherapy units, 38 (35.2 %) perform prostatic implants. Departments saw a mean of 24.9 new patients/week; the number of patients treated annually was 102,054, corresponding to 88.4 % of patients with a RT indication. In 56.5 % of the hospitals, multidisciplinary teams were available to treat PC.

CONCLUSIONS

Results provide an accurate picture of current situation of RO in Spain, showing a trend toward the progressive introduction of new technologies (IMRT, IGRT, brachytherapy).

AuPd/polyaniline as the anode in an ethylene glycol microfluidic fuel cell operated at room temperature

AuPd/polyaniline was used for the first time, for ethylene glycol electrooxidation in a microfluidic fuel cell operated at room temperature.

Reproducibility of observables and coherent control in molecular photoionization: from continuous wave to ultrashort pulsed radiation

One-photon single ionization of molecules has been at the focus of several discussions concerning the reconstruction of observables obtained with ultrashort pulses from those obtained from continuous wave radiation (and vice versa). A related controversy on the conditions and observables that allow for coherent control in one-photon processes has been recently revisited (Science 2006, 313, 1257; J. Chem. Phys. 2010, 133, 151101). Our benchmark to investigate these issues is photoionization of the hydrogen molecule, where the autoionization events are the time-dependent processes in field-free evolution that could serve as a target for coherent control. We show that the variation of one-photon ionization probabilities with pulse duration are solely due to spectral effects and thus cannot be coherently controlled. We then discuss for which observables and under which conditions phase control of autoionization dynamics is possible.

Observation of interference between two distinct autoionizing states in dissociative photoionization of H2

Dissociative photoionization (DPI) of randomly oriented H(2) molecules has been studied using linearly polarized synchrotron radiation at selected photon energies of 31, 33, and 35 eV. Large amplitude oscillations in the photoelectron asymmetry parameter β, as a function of electron energy, have been observed. The phase of these β oscillations are in excellent agreement with the results of recent close coupling calculations [Fernández and Martín, New J. Phys. 11, 043020 (2009)]. We show that the oscillations are the signature of interferences between the 1Q(1) (1)Σ(u)(+) and 1Q(2) (1)Π(u) doubly excited states decaying at different internuclear distances. The oscillations thus provide information about the classical paths followed by the nuclei. The presence of such oscillations is predicted to be a general phenomenon in DPI.

Susceptibility to peroxidation and fatty acid composition of fresh boar semen obtained from different hog farms

<p>Objectives of this study were to determine the fatty acid composition and to analyze the sensitivity to lipid peroxidation of different boar fresh semen samples from two herds, H1 and H2. Lipid peroxidation was evaluated using chemilu­minescence (cpm/mg of protein) and fatty acid profile by means of gas chromatography. The saturated fatty acid content found in the analyzed spermatozoa was approximately 43% in H1 and 33% in H2, whereas the total unsaturated fatty acid content was 47% in H1 and 59% in H2. When control and ascorbate-Fe++ dependent samples were compared, it was observed a significant increase in light emission. Consequently, significant decrease in the percentage of the polyunsaturated fatty acids was determined, being more affected: C22: 5 n6 and C22: 6 n3 in both herds, whereas C20: 4 n6 and C22: 4 n6 only in H2. The great amounts of polyun­saturated fatty acids found in H2 samples could be related to the loss of acrosomal integrity. Our results indicate that boar semen contains great amounts of polyunsaturated fatty acid in its composition, which were vulnerable to the lipid peroxidation.</p>

Components of (co)variance of the days open in Siboney dairy cows

The records of 63,406 calvings of Siboney dairy cows (5/8 Holstein 3/8 Cuban Zebu) were used to estimate the components of covariance of the days open (DO). Five models were used: of repeatability; univariate; bivariate; of random regression with Legendre polynomials and the parity number as predicting variable; and a model of random regression with Legendre polynomials and heterogeneity of the residual variance. The heritability obtained with the univariate model was 0.09 in the first calving and decreased to 0.05 in the fifth. A higher estimate of heritability (0.12) was obtained with the repeatability model. When the model of random regression with heterogeneity of the residual variance was used, the heritability was higher than the values estimated with the previous models. The genetic correlations among the DO in different calvings, estimated with the models of random regression with and without heterogeneity of the residual variance, were close to 1.0. It is concluded that the estimates of heritability increased with the use of the random regression models. The genetic correlations among the DO of different calvings indicated that in the first three, the DO are regulated for the most part by the same genes.

Two-electron time-delay interference in atomic double ionization by attosecond pulses

A two-color two-photon atomic double ionization experiment using subfemtosecond uv pulses can be designed such that the sequential two-color process dominates and one electron is ejected by each pulse. Nonetheless, ab initio calculations show that, for sufficiently short pulses, a prominent interference pattern in the joint energy distribution of the sequentially ejected electrons can be observed that is due to their indistinguishability and the exchange symmetry of the wave function.

[Oral nutritional supplementation in hematologic patients]

RATIONALE

Hematological patients often present anorexia which along with other secondary effects from the chemotherapy and/or radiotherapy treatments compromise their nutritional status. Oral supplementation can aid to fulfill the energy and protein requirements of these patients. Nevertheless, the use of commercial nutritional supplements normally available, is limited by its poor intake.

OBJECTIVE

To evaluate the degree of fulfillment of the prescribed supplements and fulfillment of energy requirements, as well as the development of nutritional status in hematological patients hospitalized for treatment with chemotherapy and/or radiotherapy.

METHODS

Prospective, randomized and open study of inpatients at the hematological ward. Patients were randomized sequentially and they were assigned into 3 different nutritional interventions providing: Group 1 (G1), a flavored supplement; Group 2 (G2): a non flavored (neutral) supplement and Group 3 (G3): "kitchen" foods as supplements. Need and amount of nutritional supplements were provided according to the oral intake previously analyzed. Nutritional assessment (at admission and discharge) was based in the Subjective Global Assessment test (SGA), Risk Nutritional Index (RNI) and percentage of lost weight. Both fulfillment of supplement intake and achievement of energetic requirements were analyzed.

RESULTS

125 patients of 51.3 +/- 16.8 years; 45% men and 55% women.

DIAGNOSIS

54% lymphoma, 33% leukemia, 8% myeloma and others 4%. Length of stay (LOS): 7.0 +/- 3.6 d. The nutritional assessment done by SGA showed significant negative changes in G2 and G3 (G1: 30% developed malnutrition and 28% improved their nutritional status, p = NS; G2: 50% developed malnutrition against 7% whom improved their nutritional status, p = 0.002; y G3: 37% developed malnutrition against 21% whom improved their nutritional status, p = 0.02). According to RNI, patients evolved negatively from their nutritional state but no significant differences were found within groups (G1, from 81% of malnutrition to 90%; G2, from 77% to 91%, and G3 from 71% to 85%). Globally, during hospitalization patients lost weight significantly (2.3 +/- 2.2 kg, p < 0.001), but within groups weight loss differences were not significant (G1, 1.16 kg; G2, 1.75 kg, y G3, 1.17 kg). All three groups required intake of supplements (G1, 47%; G2, 30%, and G3, 47%). The percentage of fulfillment of oral intake was similar in both commercial supplemented groups (G1, 47% and G2, 58%) although it was significantly greater in those receiving kitchen supplements (G3, 100%, p < 0.001). The fulfillment of energy requirements at admission and discharge did not showed significant changes (G1, from 53% to 46%; G2, from 67% to 52% and G3 from 49% to 55%).

CONCLUSION

Our results suggest that hematological patients admitted to hospital for treatment with chemotherapy and/or radiotherapy loose weight during their hospitalization and present intakes below their energy requirements so they need supplementation. Kitchen supplements are better accepted than commercial ones although that does not result in an increased total energy intake. The group which received commercial flavored supplements was the only one which did not showed negative significant changes in the nutritional status evaluated by SGA.