Observation of Correlations between Spin and Transverse Momenta in Back-to-Back Dihadron Production at CLAS12.

We report the first measurements of deep inelastic scattering spin-dependent azimuthal asymmetries in back-to-back dihadron electroproduction in the deep inelastic scattering process. In this reaction, two hadrons are produced in opposite hemispheres along the z axis in the virtual photon-target nucleon center-of-mass frame, with the first hadron produced in the current-fragmentation region and the second in the target-fragmentation region. The data were taken with longitudinally polarized electron beams of 10.2 and 10.6 GeV incident on an unpolarized liquid-hydrogen target using the CLAS12 spectrometer at Jefferson Lab. Observed nonzero sinΔϕ modulations in ep→e^{'}pπ^{+}X events, where Δϕ is the difference of the azimuthal angles of the proton and pion in the virtual photon and target nucleon center-of-mass frame, indicate that correlations between the spin and transverse momenta of hadrons produced in the target- and current-fragmentation regions may be significant. The measured beam-spin asymmetries provide a first access in dihadron production to a previously unexplored leading-twist spin- and transverse-momentum-dependent fracture function. The fracture functions describe the hadronization of the target remnant after the hard scattering of a virtual photon off a quark in the target particle and provide a new avenue for studying nucleonic structure and hadronization.

Observation of Azimuth-Dependent Suppression of Hadron Pairs in Electron Scattering off Nuclei.

We present the first measurement of dihadron angular correlations in electron-nucleus scattering. The data were taken with the CLAS detector and a 5.0 GeV electron beam incident on deuterium, carbon, iron, and lead targets. Relative to deuterium, the nuclear yields of charged-pion pairs show a strong suppression for azimuthally opposite pairs, no suppression for azimuthally nearby pairs, and an enhancement of pairs with large invariant mass. These effects grow with increased nuclear size. The data are qualitatively described by the gibuu model, which suggests that hadrons form near the nuclear surface and undergo multiple scattering in nuclei.These results show that angular correlation studies can open a new way to elucidate how hadrons form and interact inside nuclei.

Seismic Applications of Downhole DAS.

Distributed Acoustic Sensing (DAS) is gaining vast popularity in the industrial and academic sectors for a variety of studies. Its spatial and temporal resolution is ever helpful, but one of the primary benefits of DAS is the ability to install fibers in boreholes and record seismic signals in depth. With minimal operational disruption, a continuous sampling along the trajectory of the borehole is made possible. Such resolution is highly challenging to obtain with conventional downhole tools. This review article summarizes different seismic uses, passive and active, of downhole DAS. We emphasize current DAS limitations and potential ways to overcome them.

Improved Λp Elastic Scattering Cross Sections between 0.9 and 2.0 GeV/c as a Main Ingredient of the Neutron Star Equation of State.

Strange matter is believed to exist in the cores of neutron stars based on simple kinematics. If this is true, then hyperon-nucleon interactions will play a significant part in the neutron star equation of state. Yet, compared to other elastic scattering processes, there is very little data on Λ-N scattering. This experiment utilized the CEBAF Large Acceptance Spectrometer (CLAS) detector to study the Λp→Λp elastic scattering cross section in the incident Λ momentum range 0.9-2.0 GeV/c. These are the first data on this reaction since the 1970s. The new cross sections have significantly better accuracy and precision than the existing world data, and the techniques developed here can also be used in future experiments.

First Measurement of Timelike Compton Scattering.

We present the first measurement of the timelike Compton scattering process, γp→p^{'}γ^{*}(γ^{*}→e^{+}e^{-}), obtained with the CLAS12 detector at Jefferson Lab. The photon beam polarization and the decay lepton angular asymmetries are reported in the range of timelike photon virtualities 2.25

[Repair of umbilical hernia in postmenopausal women]. / La riparazione dell'ernia ombelicale nella donna in postmenopausa.

The Authors report their personal experience on the employment of the dual-mesh in PTFE for the treatment of the umbilical hernias in postmenopausal women. The prosthetic repair versus the classic Mayo's technique finds justification for the biostructural deficits of the muscolofascial structures of the women in menopause, due to the reduction of the ovarian function and made worse from previous pregnancies. An evaluation of the trofism of the structures of the abdominal wall and the dimensions of the hernias is however indispensable in the choice of the prosthetic surgery. In our casuistry the reported morbidity due to immediate complications is absolutely negligible. Up to the present, although the follow-up is still short, we have not found recurrences.

[Risk factors for fetal and neonatal brain injury]. / Fattori di rischio per il danno cerebrale fetale e neonatale.

Epidemiological studies have suggested a strong association of fetal and neonatal brain damage with fetal infections and free radical release. Intrauterine infection and hypoxia ischemia appear to share some characteristics, including high levels of cytokines and adhesion molecules. The relevance of the actions of cytokines to a variety of neurological disorders has opened a potentially fruitful area of research and therapeutic development.

Increased sensitivity to peroxidizing agents is correlated with an imbalance of antioxidants in normal melanocytes from melanoma patients.

We have previously shown an imbalance of the antioxidant system in some cultures of normal melanocytes from patients with melanoma. In order to evaluate if the alteration of the antioxidants could be the basis of an increased sensitivity to exposure to peroxidative agents, in cultured melanocytes from normal individuals (n = 11) and from patients with melanoma (n = 11), superoxide dismutase and catalase activities were evaluated by spectrophotometer, and the levels of vitamin E and of the polyunsaturated fatty acid of cell membranes were determined by gas chromatography mass spectrometry. In 5 out of the 11 cultures of melanocytes from melanoma patients, with respect to those from normal individuals, a significant decrease of catalase activity (Cat) associated with an increase of vitamin E (Vit E) concentration was found, whereas no significant modification of superoxide dismutase activity (SOD) was observed. A wide range of variability was detected in the percentage of the polyunsaturated fatty acids of the cell membranes and a correlation was found between the ratio SOD/Cat and the percentage of linoleic acid, indicating that the imbalance of the enzymatic antioxidants leads to a lipoperoxidative process. The electron microscopic examination of these cultures revealed many microvilli in the plasma membranes and nuclear infoldings and in the cytoplasm light vacuoles. Moreover some cells contained several dense bodies with a round shape and numerous spherical lamellae possibly representing immature melanosomes. Treatment with cumene hydroperoxide between 0.66 and 20 microM did not produce a significant modification of cell viability in melanocytes from normal individuals. On the contrary in melanocytes from melanoma patients correlated with the ratio Vit E/Cat, considered as a parameter of the antioxidant imbalance, a stimulatory effect was observed at 0.66 microM CUH and a cytotoxic effect at 20 microM. In conclusion our results suggest that a constitutional alteration of the scavenger system could be present in normal melanocytes from melanoma patients and that this could be the basis for an increased sensitivity to pro-oxidant agents.

Non-fibrous inorganic particles in bronchoalveolar lavage fluid of pottery workers.

AIM: To study the actual exposure of pottery workers to silica particles, as their risk of silicosis is potentially high because of the presence of inhalable crystalline silica particles in the workplace. METHODS: Nine pottery workers underwent bronchoalveolar lavage. The recovered fluid was analysed for cytological and mineralogical content by analytical transmission electron microscopy. The data were compared with those obtained from a control group composed of seven patients with sarcoidosis and six patients with haemoptysis. RESULTS: Cytological results showed a similar profile in exposed workers and controls, whereas in patients with sarcoidosis a lymphocytic alveolitis was found. Microanalysis of the particulate identified the presence of silicates, CRSs, and metals. Pottery workers had higher numbers of total particles and CRSs, and had a higher silicate/metal ratio. In five workers, the presence of zirconium silicate was also detected. Patients with sarcoidosis had the lowest number of particles, and an inverted silicate/metal ratio. CONCLUSION: Microanalysis by transmission electron microscope can provide useful information to assess occupational exposure to dusts.

Inorganic particles in bronchoalveolar lavage fluids from nonoccupationally exposed subjects.

This study comprised 30 patients who had not been exposed occupationally to dusts, but for whom a diagnosis of suspected pulmonary carcinoma had been made. Bronchoalveolar lavage fluids from these patients were analyzed by transmission electron microscopy and by energy-dispersive x-ray microanalysis in an effort to study the mineral particulate present in the alveolar region. Particles of silica, silicates, oxides, sulphates, and metal alloys were detected in various percentages in each subject. The smoking habits of two groups of patients that were defined by their bronchoalveolar lavage particulate concentrations (i.e., lower or higher than the median of the distribution) differed significantly.

Protective effect of N-acetylcysteine in tumor necrosis factor-alpha-induced apoptosis in U937 cells: the role of mitochondria.

The existence of two different pathways for cell death has been postulated. In addition to the passive and traumatic process leading to necrosis, an active program characterized by organelle integrity and called apoptosis has been described. A positive correlation between the apoptotic cell death process and oxidative imbalance has been demonstrated. In fact, the antioxidant N-acetylcysteine (NAC) seems to be capable of impairing the apoptotic program, replenishing intracellular reduced glutathione content in cells exposed to tumor necrosis factor-alpha (TNF) as apoptotic inducer. Moreover, protein synthesis inhibitors such as cycloheximide (CHX) can facilitate apoptotic triggering by TNF, and mitochondrial function was suggested to be essential in the TNF-mediated apoptotic process. With this in mind, a specific analysis using the JC-1 probe, a fluorescent dye which is capable of indicating mitochondrial membrane potential (delta psi m) changes, was carried out. Our results show that TNF exposure is capable of altering the mitochondria and that NAC protection from CHX + TNF-induced apoptosis could be due to a direct effect of the drug on mitochondrial integrity and function.

A novel action for adenosine: apoptosis of astroglial cells in rat brain primary cultures.

2-chloro-adenosine induced apoptosis of astroglial cells in rat brain cultures, as shown by flow cytometry and morphological analysis. The adenosine analogue was far more potent than several previously characterized sugars (including 2-deoxy-D-ribose and D-ribose, the sugar moiety of 2-chloro-adenosine), which trigger apoptosis in a variety of cell-lines [8-10], suggesting that the effects of 2-chloro-adenosine are only partially dictated by its sugar moiety. Nevertheless, 2-chloro-adenosine and 2-deoxy-D-ribose attenuated each other's cell death when used in combination, suggesting the involvement of common intracellular mechanisms. It is suggested that 2-chloro-adenosine may induce apoptosis via a yet-to-be identified adenosine receptor, which may have intriguing implications for both nervous system development and brain response to trauma and ischemia.

Low dose lidocaine combined with magnesium sulfate in warning ventricular arrhythmias.

This study was designed to assess if low dose lidocaine (L) (0.8 mg/min at a constant rate infusion following a 100 mg bolus) combined with magnesium sulfate (M) (2.5 mg/min) controlled warning ventricular arrhythmias (a total of 119,806 ectopic beats and 146 runs of sustained ventricular tachycardia) in 7 (17%) out of 41 patients undergoing ambulatory monitoring. L alone was administered during the first 48 hours, then L+M for 48 hours, followed by L alone for a further 48 hours. Every 12 hours L serum levels were measured. Serum levels of L alone ranged from 0.33 to 2.06 mg/l (mean: 1.28 +/- 0.7 mg/l) during the first 48 hours and from 0.30 to 2.96 mg/l (mean: 1.24 +/- 1.02 during the last 48 hours). When the subjects received L+M, L serum levels were 0.69 to 3.28 mg/l (mean: 1.60 +/- 0.9 with p less than 0.05, statistically significant). Ambulatory monitoring also displayed a 70% reduction in warning ventricular arrhythmias during L+M treatment. L+M are more effective in the control of warning ventricular arrhythmias and we can also administer a lower dose of lidocaine when given in combination.