Looking for the active hydrogen species in a 5 wt% Pt/C catalyst: a challenge for inelastic neutron scattering.

We looked for the active hydrogen species in a highly dispersed and very homogeneous 5 wt% Pt/C industrial catalyst (Pt particle mean diameter of 2.0 ± 0.5 nm) for hydrogenation reactions, by coupling H2 adsorption measurements with Inelastic Neutron Scattering (INS). Taking advantage of the enormous progress undergone by INS instruments, we succeeded in collecting INS spectra of unprecedented quality that allowed us to: (1) demonstrate that the Pt nanoparticles are mainly located at the regular edges of the sp2 graphitic domains on the activated carbon; (2) validate that most of the H2 physisorbed on the carbon is side-on adsorbed; (3) detect for the first time H2 molecules adsorbed on hydride-covered Pt nanoparticles; (4) observe Pt-hydrides (on the Pt/C catalyst with the lowest Pt loading among those investigated by INS so far) and (5) provide evidence for the occurrence of spillover of atomic hydrogen from the Pt surface to unsaturated reactive sites located at the irregular borders of the sp2 domains on the activated carbon.

Automated segmentation in pelvic radiotherapy: A comprehensive evaluation of ATLAS-, machine learning-, and deep learning-based models.

Artificial intelligence can standardize and automatize highly demanding procedures, such as manual segmentation, especially in an anatomical site as common as the pelvis. This study investigated four automated segmentation tools on computed tomography (CT) images in female and male pelvic radiotherapy (RT) starting from simpler and well-known atlas-based methods to the most recent neural networks-based algorithms. The evaluation included quantitative, qualitative and time efficiency assessments. A mono-institutional consecutive series of 40 cervical cancer and 40 prostate cancer structure sets were retrospectively selected. After a preparatory phase, the remaining 20 testing sets per each site were auto-segmented by the atlas-based model STAPLE, a Random Forest-based model, and two Deep Learning-based tools (DL), MVision and LimbusAI. Setting manual segmentation as the Ground Truth, 200 structure sets were compared in terms of Dice Similarity Coefficient (DSC), Hausdorff Distance (HD), and Distance-to-Agreement Portion (DAP). Automated segmentation and manual correction durations were recorded. Expert clinicians performed a qualitative evaluation. In cervical cancer CTs, DL outperformed the other tools with higher quantitative metrics, qualitative scores, and shorter correction times. On the other hand, in prostate cancer CTs, the performance across all the analyzed tools was comparable in terms of both quantitative and qualitative metrics. Such discrepancy in performance outcome could be explained by the wide range of anatomical variability in cervical cancer with respect to the strict bladder and rectum filling preparation in prostate Stereotactic Body Radiation Therapy (SBRT). Decreasing segmentation times can reduce the burden of pelvic radiation therapy routine in an automated workflow.

Finite-temperature behavior of glueballs in lattice gauge theories.

We propose a new method to compute glueball masses in finite temperature lattice gauge theory which at low temperature is fully compatible with the known zero temperature results and as the temperature increases leads to a glueball spectrum which vanishes at the deconfinement transition. We show that this definition is consistent with the Isgur-Paton model and with the expected contribution of the glueball spectrum to various thermodynamic quantities at finite temperature. We test our proposal with a set of high precision numerical simulations in the 3D gauge Ising model and find a good agreement with our predictions.

Merkel cell carcinoma in elderly: case report and review of the literature.

Merkel cell carcinoma (MCC) is a rare neuroendocrine tumour of the skin, characterised by an aggressive clinical course. The incidence of this rare neoplasia is rapidly increasing. Herein we report our experience with a patient who developed a MCC of the inguinal region.

The Hybrid Subischial Socket for Persons With Transfemoral Amputation: Gait Parameters and Clinical Assessment of a Case Series.

BACKGROUND: The subischial socket interface design is a promising new shape of socket for persons with transfemoral amputation. Typically, the proximal trim line is located distal to the ischial tuberosity, improving comfort in prosthetic users without interfering with gait parameters compared to Ischial Containment Socket (ICS). No studies have investigated the performances of a subischial sockets with suction suspension system. A new subischial socket (Hybrid Subischial Socket - HySS) combined with a hypobaric passive suspension system has been recently developed. OBJECTIVE: To assess the effects of HySS in terms of comfort, hip range-of-motion and gait parameters. METHODOLOGY: Three persons with transfemoral amputation were tested first using their usual ICS and then after one month of continuous use of HySS. FINDINGS: The following parameters improved in all participants using HySS: 1) hip range-of-motion, 2) walking speed and distance, 3) Timed-Up-and-Go-Test time, 4) stride length, 5) double support duration, 6) peak value of hip extension during stance, 7) satisfaction with the prosthesis. CONCLUSION: These findings suggest that the use of HySS could allow improvements for prosthetic use.

Imaging performance comparison between a LaBr3: Ce scintillator based and a CdTe semiconductor based photon counting compact gamma camera.

The authors report on the performance of two small field of view, compact gamma cameras working in single photon counting in planar imaging tests at 122 and 140 keV. The first camera is based on a LaBr3: Ce scintillator continuous crystal (49 x 49 x 5 mm3) assembled with a flat panel multianode photomultiplier tube with parallel readout. The second one belongs to the class of semiconductor hybrid pixel detectors, specifically, a CdTe pixel detector (14 x 14 x 1 mm3) with 256 x 256 square pixels and a pitch of 55 microm, read out by a CMOS single photon counting integrated circuit of the Medipix2 series. The scintillation camera was operated with selectable energy window while the CdTe camera was operated with a single low-energy detection threshold of about 20 keV, i.e., without energy discrimination. The detectors were coupled to pinhole or parallel-hole high-resolution collimators. The evaluation of their overall performance in basic imaging tasks is presented through measurements of their detection efficiency, intrinsic spatial resolution, noise, image SNR, and contrast recovery. The scintillation and CdTe cameras showed, respectively, detection efficiencies at 122 keV of 83% and 45%, intrinsic spatial resolutions of 0.9 mm and 75 microm, and total background noises of 40.5 and 1.6 cps. Imaging tests with high-resolution parallel-hole and pinhole collimators are also reported.

Distribution of trace elements in organs of six species of cetaceans from the Ligurian Sea (Mediterranean), and the relationship with stable carbon and nitrogen ratios.

Mercury (total and organic), cadmium, lead, copper, iron, manganese, selenium and zinc concentrations were measured in different organs of 6 different cetacean species stranded in an area of extraordinary ecological interest (Cetaceans' Sanctuary of the Mediterranean Sea) along the coast of the Ligurian Sea (North-West Mediterranean). Stable-isotopes ratios of carbon ((13)C/(12)C) and nitrogen ((15)N/(14)N) were also measured in the muscle. A significant relationship exists between (15)N/(14)N, mercury concentration and the trophic level. The distribution of essential and non-essential trace elements was studied on several organs, and a significant relationship between selenium and mercury, with a molar ratio close to 1, was found in the cetaceans' kidney, liver and spleen, regardless of their species. High selenium concentrations are generally associated with a low organic to total mercury ratio. While narrow ranges of concentrations were observed for essential elements in most organs, mercury and selenium concentrations are characterised by a wide range of variation. Bio-accumulation and bio-amplification processes in cetaceans can be better understood by comparing trace element concentrations with the stable-isotopes data.

Solubilization and methylation of HgS, PbS, and SnS by iodomethane, a model experiment for the aquatic environment.

Iodomethane is produced in the marine environment by algae and plankton. Model experiments have shown that iodomethane can dissolve a series of metal sulphides, in agreement with some of the results mentioned in the relative literature. While no dissolution of SnS was observed, PbS and HgS were dissolved proportionally with the iodomethane concentration. The two forms of HgS (cinnabar and metacinnabar) behaved differently, with metacinnabar being more soluble than cinnabar. Moreover, iodomethane can methylate lead and tin and mercury can be methylated when methyllead and methyltin compounds are present in the model system. The methylated species were identified using gas chromatography, and there is evidence that lead and tin undergo the same methylation mechanism. Preliminary experiments with natural sediments were performed, but no dissolution of Pb, Sn or Hg was observed. CAPSULE: Iodomethane can solubilize Pb and Hg sulphides, and methylate Pb and Sn, and (indirectly) Hg.

Comparison of advanced irradiation techniques with photons for benign intracranial tumours.

BACKGROUND AND PURPOSE: The potential benefits and limitations of different radiation techniques (stereotactic arc therapy (SRS/T), intensity modulated radiotherapy (IMRT), helical tomotherapy (HT), Cyberknife and intensity-modulated multiple arc therapy (AMOA)) have been assessed using comparative treatment planning methods on twelve patients presenting with 'benign' brain tumours. MATERIALS AND METHODS: Plans for five acoustic neurinomas, five meningiomas and two pituitary adenomas were computed to generate dose distributions for all modalities using a common CT dataset to delineate planning target volume and organs at risk. RESULTS: HT, AMOA and IMRT resulted superior to SRS/T and Cyberknife for target coverage. For the first group V(95%) ranged from 98% to 100%, minimum dose ranged from 91% to 96% and standard deviation from 0.84% to 1.67%. For organs at risk all techniques respected planning objectives with a tendency of Cyberknife and SRS/T to better spare the brain stem and the healthy brain tissue (e.g., V(20Gy) of 2.0% and 2.3%, respectively, compared to 3.1-5.0% for the other techniques). AMOA is in general preferable to IMRT for all OARs. Conformity index (CI(95)) was better for HT and Cyberknife (both 1.8) and less for AMOA and IMRT (3.9 and 3.0, respectively). CONCLUSION: All techniques provided good OAR sparing and primarily differed in target coverage indices. For the class of tumours investigated in this report, HT, AMOA and IMRT had better target coverage with HT providing the best combination of indeces. Between AMOA and IMRT, target coverage was comparable and, considering organs at risk, AMOA was slightly preferable.

Design of a computer-controlled multileaf collimator for advanced electron radiotherapy.

A multileaf collimator for electrons (eMLC) has been designed that fulfils the technical requirements for providing advanced irradiation techniques with electrons. In the present work, the basic design parameters of leaf material, leaf height, leaf width and number of leaves as well as leaf overtravel and leaf shape were determined such that an eMLC with motorized leaves can be manufactured by a company specialized in MLC technology. For this purpose, a manually driven eMLC with variable source-to-collimator distance (SCD) was used to evaluate the chosen leaf specification and investigate the impact of the SCD on the off-axis dose distribution. In order to select the final SCD of the eMLC, a compromise had to be found between maximum field size, minimum beam penumbra and necessary distance between eMLC and isocentre to eliminate patient realignments during gantry rotation. As a result, the eMLC is placed according to the target position at 72 and 84 cm SCD, respectively. This feature will be achieved by interchangeable distance holders. At these SCDs, the corresponding maximum field sizes at 100 cm source-to-isocentre distance are 20 x 20 cm and 17 x 17 cm, respectively. Finally, the off-axis dose distribution at the maximum opening of the eMLC was improved by fine-tuning the settings of the accelerator jaws and introducing trimmer bars above the eMLC. Following this optimization, a prototype eMLC consisting of 2 x 24 computer-controlled brass leaves is manufactured by 3D Line Medical Systems.

Prognostic significance of the 67-kilodalton laminin receptor expression in human breast carcinomas.

BACKGROUND: The 67-kd laminin receptor is a cell-surface protein that binds laminin with high affinity. In vitro studies suggest that this protein is involved in the progression of human tumors to invasive cancers (metastasis), but there have been few in vivo studies. Identification of such proteins would allow development of therapies aimed at interfering with their mechanisms of action. PURPOSE: This large retrospective study was designed to investigate the association of expression of this laminin receptor molecule with established prognostic factors and overall survival in breast carcinoma patients. METHODS: We immunohistochemically stained archival paraffin-embedded sections of 1160 primary breast carcinomas, using an immunoperoxidase technique and the MLuC5 monoclonal antibody, which is specific for the 67-kd laminin receptor. Specimens were obtained from consecutive surgeries performed from January 1968 through December 1971. Patients with negative lymph nodes or involved regional nodes had been treated with surgery alone; those with positive axillary nodes had received surgery and radiotherapy. No chemotherapy had been administered until disease recurrence. The statistical analysis was carried out using the logrank method for the survival curves and the actuarial life table to calculate survival rates according to the different prognostic variables. RESULTS: We found statistically significant associations between laminin receptor expression and young age (P < .001), premenopausal status (P = .001), positive axillary lymph nodes (P = .01), peritumoral lymphatic invasion (P = .02), and the diameter of the tumor (P = .05). Moreover, the association of expression of the receptor protein with poor prognosis, as indicated by survival curves, was statistically significant (P < .01). For patients with receptor-negative tumors, the survival rate was 50% at 20 years; for those with receptor-positive tumors, the survival rate was 50% at 13 years. Multivariate analysis showed the laminin receptor to be an independent prognostic factor (P = .005), indicating its predictive value in relation to overall survival. CONCLUSIONS: Our data suggest that the 67-kd laminin receptor is associated with the metastatic process. IMPLICATIONS: These preliminary findings also suggest that hormones may have a regulatory role in the in vivo expression of the 67-kd laminin receptor, which supports the hypothesis that hormone therapy might inhibit expression of the receptor. Studies of expression of this receptor in tumors of patients with extremely different sex hormone levels (e.g., men and pregnant women) are in progress.

Studies on the degradative mechanism of phosphoenolpyruvate carboxykinase from yeast Saccharomyces cerevisiae.

Previous work carried out in our laboratory (Burlini, N., Lamponi S., Radrizzani, M., Monti, E. and Tortora P. (1987) Biochim. Biophys. Acta 930, 220-229) led to the immunological identification of a yeast 65-kDa phosphoprotein as a modified form of phosphoenolpyruvate carboxykinase; moreover the appearance of this phospho form was proven to be independent of cAMP, whereas the glucose-induced inactivation of the native enzyme is cAMP-dependent. Here, we report further investigations on the mechanism of the glucose-triggered degradation of the enzyme which led to the following results: (a) the aforementioned phospho form displayed a binding pattern to 5 AMP-Sepharose 4B quite similar to that of native enzyme, although it did not retain its oligomeric structure, nor was it catalytically active; (b) its phosphate content was of about two residues per monomer; (c) its isoelectric point was slightly higher than that of native enzyme, this shows that the enzyme undergoes additional modifications besides phosphorylation; (d) it represented about 4% of the native enzyme in glucose-depressed cells; (e) other forms immunologically cross-reactive with the native enzyme were also isolated, whose molecular mass was in the range of 60-62 kDa, and they are probable candidates as degradation products of the phospho form; (f) time courses of the native and phospho forms in the presence and the absence of glucose provided data consistent with a kinetic model involving a strong stimulation of the decay of both forms effected by the sugar; (g) in the mutant ABYS1 (Achstetter, T., Emter, O., Ehmann, C. and Wolf, D.H. (1984) J. Biol. Chem. 259, 13334-13343) which is devoid of the four major vacuolar proteinases, the decay pattern was essentially the same as in wild-type; (h) effectors lowering intracellular ATP also retarded the first step of enzyme degradation; this points to an ATP-dependence of this step. Based on these results we propose a degradation mechanism consisting of an initial cAMP- and ATP-dependent modification of the enzyme, followed by a cAMP-independent phosphorylation, which leads to the appearance of the aforementioned monomeric phospho form; this in turn seems to undergo limited proteolysis. These data strongly suggest the occurrence of an intermediate form arising from the native one and whose phosphorylation gives rise to the 65-kDa phosphoprotein described here.

Ising-model description of long-range correlations in DNA sequences.

We model long-range correlations of nucleotides in the human DNA sequence using the long-range one-dimensional (1D) Ising model. We show that, for distances between 10(3) and 10(6) bp, the correlations show a universal behavior and may be described by the non-mean-field limit of the long-range 1D Ising model. This allows us to make some testable hypothesis on the nature of the interaction between distant portions of the DNA chain which led to the DNA structure that we observe today in higher eukaryotes.

Characterization of two monoclonal antibodies directed against the 67 kDa high affinity laminin receptor and application for the study of breast carcinoma progression.

Two monoclonal antibodies (mAbs), designated MLuC5 and MLuC6, were produced against a human small cell lung carcinoma cell line. They were found to exhibit a superimposable reactivity on different cell lines and on platelets. Moreover, they both immunoprecipitated a 67 kDa molecule from the membrane of the reference target cells. Immunodepletion and cross-inhibition tests indicated that the two mAbs recognize two epitopes closely localized on the same molecule. The MLuC5 mAb was further characterized for its reactivity on platelets. Immunoprecipitation and ELISA assays demonstrate that this mAb recognizes the 67 kDa high affinity laminin receptor. MLuC5 reactivity was evaluated by immunohistochemistry on a variety of normal and tumor tissues, in particular breast specimens including normal epithelium, dysplastic lesions, in situ carcinomas, invasive primary carcinomas and distant metastases. The laminin receptor was found to be strongly expressed in 50% of the infiltrating carcinomas, whereas in situ carcinomas and benign lesions, as well as the normal mammary epithelium, were only weakly and focally positive. In metastatic lesions MLuC5 reactivity was only found in 11% of the samples tested, independently of the site of origin of the lesion.

Spontaneous lung metastases in a human lung tumor xenograft: a new experimental model.

The cell line NIH-H460, derived from a human large-cell carcinoma of the lung, because metastatic in the lung of athymic mice after S.C. injection. Using serial S.C. passages of the lung metastasis, a cell line was selected, H460M, which was characterized by an increased metastatic potential compared to the parental cells after s.c. (Spontaneous metastases) or i.v. injection (experimental metastases). For the high frequency of lung metastases in the mouse and the short time required to develop metastatic foci, the H460M cells transplanted in nude mice represent a unique preclinical model for biological and therapeutic studies. The paper describes the growth and some biological properties (invasion and migration capability, membrane profile) of this experimental in vivo model.

Aneurysms of the high internal carotid artery: a new approach.

Aneurysms of the high internal carotid artery, though rare, present a therapeutic problem. Presented herein is a case report and a method of primary repair.

Pneumonectomy for unremitting hemoptysis in unilateral absence of pulmonary artery.

Unilateral absence of pulmonary artery is a rare malformation that can present as an isolated lesion or may be associated with other congenital heart defects. Clinical presentation is subtle when the lesion occurs alone, and may include hemoptysis, which results from rupture of abundant bronchial submucosal vessels perfused by enlarged systemic collaterals that supply the affected lung. Pneumonectomy is recommended as definitive treatment in such an adult patient.

Revascularization of the circumflex coronary artery in the atrioventricular groove.

Complete myocardial revascularization entails the grafting of all vessels of adequate size demonstrating occlusive arteriosclerotic vascular disease. Revascularization of the circumflex coronary artery in the atrioventricular groove has been a major surgical challenge because of the difficulty of exposing it. We discuss here our operative technique in 12 consecutive patients requiring revascularization of that segment of the circumflex coronary artery. Eleven grafts studied in the postoperative period were found to be patent, and the clinical course of the remaining patient and direct observations, including enzyme studies and periodic stress testing, have not shown any evidence of graft failure.

Blunt rupture of both atrioventricular valves.

Younger patients are surviving extensive damage to the heart and supporting structures, often associated with multiple systems injuries. A 23-year-old patient who sustained blunt trauma to the chest resulting in a pericardial laceration, injury to tricuspid and mitral valves, myocardial contusion, and paresis of the left phrenic nerve is reported. Porcine bioprosthetic valve replacement of both atrioventricular valves was necessary. Prompt diagnosis and aggressive intervention of such injuries can lead to successful repair of complex cardiac trauma.