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Study question Do different gonadotrophins for controlled-ovarian-stimulation (COS) affect metaphase-II (MII) oocyte competence? Summary answer Euploid blastocyst rate (EBR) per cohort of MII-oocytes, live-birth-rate (LBR) per first vitrified-warmed euploid single-embryo-transfer (SET) and cumulative-LBR are independent from the gonadotrophins used. What is known already Controlled-ovarian-stimulation (COS) is a cornerstone of IVF. Its purpose is maximizing ovarian reserve exploitation and obtaining ≥1 euploid blastocyst to transfer. Indeed, ovarian reserve decreases and blastocyst aneuploidy rates increase with increasing maternal age, making this task quite complicated in advanced maternal age. Old-fashioned studies suggested an association between COS and embryonic aneuploidy rates. Conversely, recent studies excluded an impact of COS dosage, duration, ovarian response, and ovulation trigger, on blastocyst aneuploidy rate. An aspect, though, needs more clarity: do different gonadotropins impact oocyte competence after COS, comprehensively defined as EBR per cohort of MII-oocytes? Study design, size, duration Out of 3169 PGT cycles with ³1 MII oocyte conducted between 2014-2018, we excluded (i)PGT-M/-SR, (ii)women Participants/materials, setting, methods Only GnRH-antagonist COS, ICSI with fresh MII-oocytes, single culture in continuous-media, trophectoderm biopsy without assisted-hatching, comprehensive-chromosome-testing to assess full-chromosome non-mosaic aneuploidies and vitrified-warmed euploid SET were conducted. Oocyte competence was comprehensively defined as EBR per cohort of MII-oocytes with all intermediate outcomes (fertilization, blastulation and euploidy). LBR per first vitrified-warmed euploid SET and cumulative-LBR per retrieval were also assessed. Generalized-linear-models and multivariate regressions were adopted to adjust the results for confounders. All cycles were concluded. Main results and the role of chance Patients using recFSH+recLH and recFSH+HMG (40.7 yr) were older than patients using recFSH-only or HMG-only (40 yr; ANOVA Limitations, reasons for caution The gonadotrophins were chosen based on patient compliance to their administration route and gynecologist judgement, and only qualitative outcomes were assessed. Therefore, randomized-controlled-trials and cost-effectiveness analysis investigating the efficiency in oocyte recruitment and cumulative-LBR per intention-to-treat are needed. Wider implications of the findings Different gonadotrophins might not affect MII-oocyte competence. This information is key since, in view of the optimization of follicle recruitment through personalized-COS, it allows more flexibility in the choice of the most suitable protocol. Therefore, gynecologists might ponder also features like patient reproductive history and compliance to different administration routes. Trial registration number none

Study question Is double stimulation in the same ovarian cycle (DuoStim) a valuable strategy to improve the chance of success in couples carrier of monogenic conditions? Summary answer DuoStim is advantageous in patients indicated for preimplantation genetic testing for monogenic diseases and aneuploidy testing (PGT-M/-A) and obtaining ≤5 blastocysts after the I-stimulation. What is known already PGT-M is a well-established strategy to identify unaffected blastocysts in a cohort of embryos produced from couples carrier of single gene disorders. When PGT-M is conducted in poor prognosis and/or advanced maternal age (POR/AMA) patients, also aneuploidy-testing among unaffected blastocysts is suggested on a single biopsy. The Poseidon group stated that retrieving an adequate number of oocytes to produce ≥1 euploid blastocyst should be considered the main goal of controlled-ovarian-stimulation (COS). This task is even more complex when PGT-M is required in POR/AMA patients. Therefore, lately we started suggesting DuoStim to these couples to maximize their chance of success. Study design, size, duration Multicenter case series (2016-2021). Comprehensive description of IVF outcomes derived from DuoStim application in POR/AMA patients undergoing PGT-M. Aneuploidy-testing was also conducted on unaffected blastocysts. All results were compared between the two stimulations in the same ovarian cycle, and we reported the contribution of II-stimulations to higher chances of success. Participants/materials, setting, methods GnRH-antagonist COS was performed with recombinant-gonadotrophins and agonist-trigger. Based on the expected risk each embryo would be affected-aneuploid, DuoStim was suggested to all patients obtaining ≤5 blastocysts (day5-7 from I-retrieval). 61 patients accepted and underwent II-stimulations with the same protocol. Only ICSI, trophectoderm-biopsy, qPCR, and vitrified-warmed unaffected-euploid single-blastocyst-transfer(s) were conducted. Main results and the role of chance 90 patients (36.7±3.7yr) indicated to PGT-M/-A and obtaining ≤5 blastocysts after I-stimulations were suggested starting a II-stimulation in the same ovarian cycle. Among them, 61 accepted (67%). 7.2±4.4 and 7.4±4.2 cumulus-oocyte-complexes were retrieved after I- and II-stimulations, respectively (p = 0.7). 5.1±3.0 and 5.8±3.4 were metaphase-II oocytes (p = 0.2), resulting in 75±21% and 77±25% maturation-rates (p = 0.6). 3.6±2.1 and 4.6±2.9 2PN-zygotes were obtained (p = 0.04), resulting in 75±27% and 81±20% fertilization-rates (p = 0.19). 1.6±1.3 and 2.2±1.8 blastocysts were obtained (p = 0.04), resulting in 43±32% and 46±32% blastulation-rates (p = 0.6). Lastly, 0.5±0.7 and 0.7±1.0 blastocysts were diagnosed unaffected-euploid (p = 0.3), resulting in 35±40% and 30±36% transferable blastocyst rates per biopsied embryo, respectively (p = 0.53), and identical 10±16% transferable blastocyst rates per metaphase-II oocyte in both groups (p = 0.9). 23 (38%) and 24 (39%) patients obtained ≥1 transferable blastocyst after the I- and II-simulation, respectively. Overall, 36 (59%) patients obtained ≥1 transferable blastocyst thanks to DuoStim. To date, 57 (93%) cycles were concluded, and the cumulative live birth rate (CLBR) was 37% (N = 21/57). The patients with a LB have 1.7 surplus transferable blastocysts, and 3 patients already delivered 2 singleton healthy-LBs. The CLBR among patients undergoing the conventional strategy was 21%, no surplus transferable blastocyst is available, and no patient delivered >1 LB. Limitations, reasons for caution Observational case series based on real-life data. Of note, the adoption of DuoStim (or any other oocyte/embryo accumulation strategy) in PGT-M/-A is valuable also to amortize the costs of PGT-M set-up and genetic testing through a larger number of blastocysts. In this context, cost-effectiveness analyses in different settings are desirable. Wider implications of the findings DuoStim is a fully-personalized strategy advisable any time lower chance of success and higher treatment costs could be balanced by a larger number of blastocysts produced in a short time-frame. Adopting GnRH-antagonist protocols in these patients allows to suggest DuoStim even in progress, based on the embryological outcomes after I-stimulations. Trial registration number Not applicable

Funding Acknowledgements Type of funding sources: Private company. Main funding source(s): The E-MIOT project receives “no-profit support” from industrial sponsorships (Chiesi Farmaceutici S.p.A. and Bayer). Background The T2* magnetic resonance imaging (MRI) technique for the noninvasive quantification of iron overload has significantly improved the survival of patients with hemoglobinopathies by tailoring the chelation therapy. In Italy, the E-MIOT (Extension-Myocardial Iron Overload in Thalassemia) Network, a collaborative project among MRI and hematological centers, has assured high-quality quantification of iron in vital organs such as heart, liver, and pancreas. The COVID-19 pandemic has disrupted healthcare services around the world, also leading to postpone or delete deferable diagnostic evaluations. Aim We evaluated the impact of the COVID-19 pandemic on MRI services for iron overload quantification in Italy. Methods The activity of the MRI centers of the E-MIOT Network in the year 2020 was compared to the activity in the same months of 2019. A specific survey was filled out by the MRI operators to evaluate if the availability of MRI slots for patients with hemoglobinothies was reduced and the reasons. Results In comparison with the year 2019, in 2020 there was a significant reduction in the number of T2* MRIs performed (350 vs 656; P Figure 2 shows the percentage of decline (year 2020 vs 2019) in the number of T2*MRI scans for each MRI center. If no decline or an increase were present, the vertical axis was set at 0. All centers experienced a significant drop in the number of the T2* MRIs in the four-month period March-June (from 75 to 100%). In the three-month period July-September only the centers of Pisa and Taranto dropped the number of T2* MRIs due to the rescheduling of the other MRI appointments deleted during the lockdown. In the three-month period October-December a reduction of the T2* MRI scans was experienced by all centers, except for Campobasso. In the centers of Ferrara and Lamezia Terme the reduction was the consequence of the general reduction in the number of the total MRIs scheduled per day for the sanitation procedures. In the other centers, the availability for T2* MRI scans was unchanged in comparison to 2019, but the patients refused the MRI follow up for fear of getting sick of COVID. Conclusion The COVID-19 pandemic is having a strong negative impact on the quantification of iron overload by MRI, which may seriously worsen the prognosis of patients with hemoglobinopathies. Strategies to ensure proved lifesaving MRI exam and to reassure patients about the health safety of the hospitals are recommended. Abstract Figure 1

BackgroundSystemic lupus erythematosus (SLE) is a chronic and complex inflammatory disease which predominantly affects young females during reproductive ages. Its prognosis is worse in males, young people, Afro-American and Latin patients. Clinical and immunological features had been described around the world but few reports had been done in Argentinian patients.ObjectivesThe purpose of this study was to describe the clinical and immunological pattern in SLE patients, characteristics of lupus nephritis (LN), disease male’s course of SLE, treatments and causes of hospitalization.MethodsRetrospective study including patients (>18 years) followed in Rheumatology Department, which had unless two visits in the last year before data collection, its clinical reports were complete, and fulfilled SLICC or EULAR/ACR SLE criteria. We recorded data from the medical reports.ResultsOf the 70 patients, 63 were female (90%). The mean age at diagnosis was 27,86 ± 9,4 years. The most frequent manifestations were arthritis (75,7%), malar rash (65,7%), photosensitivity (31,4%), leukopenia (31,4%), alopecia (31,4%), Raynaud’s phenomenon (24,3%) and nasal and oral ulcerations (21,4%).94,3% of patients were positive for antinuclear antibodies, 45,7% had anti-Ro/SSa, 28,6% anti-RNP and 21% anti-Smith. 75% had low complement and 45,7% anti-DNA antibodies.LN occurred in the 50% of patients, and class IV was the most prevalent in this group. 66% of patients developed LN in the first year of SLE diagnosis. Autoantibodies in this manifestation were: anti-DNA 60%, anti-Ro/SSa 37%, 31% anti-RNP and 26% anti-Smith.The most common comorbidity was high blood pressure followed by hypothyroidism (34,3% and 25,7% respectively). All patients received hydroxychloroquine and 62,9% prednisone; half of the patients who were into prednisone treatment received 5mg or less. Other treatments were cyclophosphamide (42,9%), mycophenolate (28,6%) and methotrexate (15,7%). 60% of patients had been hospitalized because of SLE flares and 15,7% due to infections. 75% of flares were due to LN and 8% because of serositis.Is known that SLE in male patients is more aggressive and with poor prognosis. Although this study had only 7 men, 86% had LN, 29% had pericardial and pleural effusion and 29% thrombocytopenia, were we found several differences in female’s SLE presentation.ConclusionThis study shown similar results reported in other populations. We found that 50% of SLE patients developed LN, which is the most important cause of hospitalization. Although cutaneous and musculoskeletal manifestations were the most frequent, it’s important to take into account the clinical and prognostic differences between male and female.References[1]Pons Estel B et al. The GLADEL, multinational Latin American prospective inception cohort of 1214 patients with systemic lupus erythematosus: ethnic and disease heterogeneity among Hispanics. Medicine 2004;83;1-17[2]Alarcón GS, Friedman AW, Straaton KV, et al. Systemic lupus erythematosus in three ethnic groups: III. A comparison of characteristics early in the natural history of the LUMINA cohort. LUpus in MInority populations: NAture vs. Nurture. Lupus 1999;8:197–209[3]Aringer M et al. 2019 European League Against Rheumatism/American College of Rheumatology Classification Criteria for Systemic Lupus Erythematosus. Arthritis & Rheumatology. 2019;71;1400-1412[4]Cervera R et al. Morbidity and mortality in systemic lupus erythematosus during a 10-year period. Medicine 2003; 82: 299-308Disclosure of InterestsNone declared

Because of the cascade of secondary particles, including neutrons, produced in the shielding of large spacecraft, it is important to test the reliability of electronic devices exposed to energetic (fast) neutrons. Additionally, devices located near accelerators, such as those found in cancer therapy clinics, can be exposed to a substantial fluence of neutrons.The energy spectrum of the primary neutron beam has been modeled and benchmarked extensively. To cater to a broader community interested in fast-neutron testing, we have been developing a series of neutron spectra based on scattering the primary neutron beam. A stack of plastic used to scatter the beam, was simulated using MCNP6.2 to analyze the spectra at various locations. We also use MCNP6.2 to investigate the potential of developing a softer neutron spectrum using graphite to reduce the low energy absorption which occurs in the plastic.

Objectif Au cours de l’etude de Pepin et al. (Thorax. 2016 ;71 :726-33) la PPCauto-pilotee semblait moins efficace que la PPC fixe pour reduire la pression arterielle diastolique des 24 h. Les fuites, potentiellement responsables d’une degradation de la qualite de sommeil pourraient etre un facteur explicatif. Objectifs : – comparer l’impact du mode auto-PPC versus PPC-fixe sur les fuites ; – comparer le type de masque utilise (nasal vs naso-buccal) selon le mode de PPC. Methodes Trois marques differentes de PPC etaient utilisees dans chacun des deux bras de l’etude (auto vs fixe). Le niveau de fuites etaient extraits des rapports machines a 4 mois de traitement. Le masque, la presence d’un humidificateur, d’une mentonniere etaient renseignes. Les fuites, rapportees de facon differentes selon les marques de PPC etaient classees en deux groupes : « fuites importantes » si les fuites etaient superieur a la mediane calculee pour chaque marque de PPC, ou a l’inverse « fuites faibles ». Resultats Au total, 269 patients etaient analyses. En analyses univariees, le tabagisme actif, la pression et le masque naso-buccal etaient associes a des fuites importantes mais il n’y avait pas d’association avec le mode de PPC. En analyse multivariee, seuls la pression et le masque naso-buccal restaient associes a des fuites importantes. Aucune difference n’etait observee sur le type de masque utilise selon le mode. Conclusion Le mode de PPC (auto vs fixe) n’influence ni les fuites ni le type de masque utilise.

The CRONUS-Earth and CRONUS-EU Projects have recently examined the reproducibility of cosmogenic nuclide measurements and the ability of cosmogenic-production models to fit high-quality global calibration data sets. In both cases, although results are adequate for present geochronological needs, they must be improved to meet future demands. We recommend that the cosmogenic-nuclide community embark on a continuing effort to understand the sources of the remaining model-versus-data discrepancy, and that in the meanwhile all cosmogenic ages be benchmarked against reference ages calculated in a consistent fashion. We also recommend that interlaboratory reference materials be routinely analyzed along with samples and blanks, that the results be tracked, and that methods of achieving consistency and precision in sample preparation and analysis be shared within the community. We also recommend additional organization of the community to facilitate the use of intercomparison materials, foster analytical improvements, oversee the evolution of the community age calculator, and synthesize ongoing calibration efforts.

Geological surface-exposure dating using cosmogenic-nuclide accumulation became a practical geochronological endeavor in 1986, when the utility of 10Be, 26Al, 36Cl, and 3He were all demonstrated. In response to the lack of a common basis for quantifying analytical consistency and calibrating cosmogenic-nuclide production, the CRONUS-Earth Project in the U.S. was started in 2005, along with a European partner project, CRONUS-EU. The goal of the CRONUS-Earth Project was to improve the accuracy and precision of terrestrial cosmogenic nuclide dating in general, focusing especially on nuclide production rates and their variation with altitude, latitude, and time, and to attempt to move from empirically based methods to ones with a stronger basis in physics. The CRONUS-Earth Project conducted extensive intercomparisons of reference materials to attempt to quantify analytical reproducibility at the community level. We found that stated analytical uncertainties nearly always underestimate the actual degree of variability, as quantified by the over-all coefficient of variation of the intercalibration data. The average amount by which the actual coefficient of variation exceeded the analytical uncertainty was a factor of two (100%), but ranged from 15% to 300% depending on the nuclide and material. Coefficients of variation ranged from 3−4% for 10Be to 6–8% for 36Cl, 14C, and 21Ne, to 5–11% for 26Al. Both interlaboratory bias and within-laboratory excess spread of the data played a role in increasing variability above the stated analytical uncertainties. The physical basis for cosmogenic nuclide production was investigated through numerical modeling and the measurement of energy-dependent neutron cross sections for nuclide interactions. We formulated new, physically based, scaling models, denoted LSD and LSDn, by generalizing global numerical simulations of cosmic-ray processes. The CRONUS-Earth Project identified new geological calibration sites, including one at low latitude and high elevation (Huancane, Peru), and replicated nuclide measurement at numerous laboratories. At many sites multiple nuclides were measured, providing much more confidence in the equivalence of surface-exposure ages calculated from differing nuclides. The data were interpreted using an original cosmogenic-nuclide calculator, CRONUScalc, that incorporates the new physically based scaling. The new data and model produced significantly better fits than previous efforts, but do not fully resolve apparent spatial variations in production rates. The CRONUS-Earth and CRONUS-EU Projects have provided a firm foundation for assessing the strengths and weaknesses of cosmogenic-nuclide analytical methods, adjusted the AMS standards for 10Be and consequently revised the half-life, and have provided improved calibration data sets and interpretative tools.

To account for particle interactions in the extracellular (physical) environment, information from the cell-level Monte Carlo damage simulation (MCDS) for DNA double strand break (DSB) induction has been integrated into the general purpose Monte Carlo N-particle (MCNP) radiation transport code system. The effort to integrate these models is motivated by the need for a computationally efficient model to accurately predict particle relative biological effectiveness (RBE) in cell cultures and in vivo. To illustrate the approach and highlight the impact of the larger scale physical environment (e.g. establishing charged particle equilibrium), we examined the RBE for DSB induction (RBEDSB) of x-rays, (137)Cs γ-rays, neutrons and light ions relative to γ-rays from (60)Co in monolayer cell cultures at various depths in water. Under normoxic conditions, we found that (137)Cs γ-rays are about 1.7% more effective at creating DSB than γ-rays from (60)Co (RBEDSB = 1.017) whereas 60-250 kV x-rays are 1.1 to 1.25 times more efficient at creating DSB than (60)Co. Under anoxic conditions, kV x-rays may have an RBEDSB up to 1.51 times as large as (60)Co γ-rays. Fission neutrons passing through monolayer cell cultures have an RBEDSB that ranges from 2.6 to 3.0 in normoxic cells, but may be as large as 9.93 for anoxic cells. For proton pencil beams, Monte Carlo simulations suggest an RBEDSB of about 1.2 at the tip of the Bragg peak and up to 1.6 a few mm beyond the Bragg peak. Bragg peak RBEDSB increases with decreasing oxygen concentration, which may create opportunities to apply proton dose painting to help address tumor hypoxia. Modeling of the particle RBE for DSB induction across multiple physical and biological scales has the potential to aid in the interpretation of laboratory experiments and provide useful information to advance the safety and effectiveness of hadron therapy in the treatment of cancer.

Characteristics of the spallogenic component of nuclide production are investigated through the use of a physics-based model. Calculated production rates for commonly used nuclides indicate differences in scaling up to 15% at very high altitude. Angular distribution of nuclide forming particles suggests the current method of shielding correction, which is neither altitude nor latitude dependent, can be improved on. Subsurface production profiles suggest that erosion corrections should be performed with non-constant attenuation lengths. Results are parameterized for easy application.

We present a comprehensive, nuclear-physics-based cosmogenic nuclide production rate model combining radiation transport modeling with excitation functions for commonly measured nuclides. This model allows investigation of factors influencing nuclide production, such as the energy spectrum and angular distribution of the incident radiation that cannot be easily isolated in calibration measurements on natural samples. We present neutron and proton fluxes over a range of atmospheric depths and cut-off rigidities. Calculated production rates for 3He, 10Be, 14C, 21Ne, 26Al, and 36Cl based on these fluxes are presented. The model predicts that production rates for these nuclides diverge from one another with altitude, hence that production ratios depend on altitude. Compared to existing scaling schemes, the model predicts a larger difference between sea-level production rates at low and high latitude.

Some potential applications of the isotopes 36 Cl and 236 U require higher sensitivity than is normally required or achieved. For 36 Cl, one such application is the measurement of the 36 Cl/Cl ratio of seawater. We show that, with appropriate precautions to reduce the effect of ion-source memory, it is possible to reach blank levels below 10 −16 in the 36 Cl/Cl ratio. Measurements of a series of seawater and sea salt samples yield a blank-corrected 36 Cl/Cl ratio of present-day sea water of 0.71 ± 0.08 × 10 −15 . For 236 U, one potential application is as a prospecting tool, where sensitivities in the 236 U/ 238 U ratio at the 10 −13 level are desirable. We demonstrate that this sensitivity can be achieved for 24 MeV uranium ions with time-of-flight detection over a 6.0 m flight path.

In this study, we use physics based cross sections and the radiation transport code MCNPX to develop a purely physics based global model of cosmogenic nuclide production. Modeling the earth as a series of concentric, spherical shells of various media, we propagate the radiation cascade resulting from bombarding the model with primary protons and helium nuclei. The hadronic component of the radiation cascade is tracked throughout the atmosphere as well as the upper region of simple, rock earth-planets. Tallying the energy spectrum throughout the geometry allows us to fold the energy dependent flux with excitation functions to determine nuclide specific spallogenic production rates and attenuation lengths. Using these results, we characterize facets of the radiation cascade and resulting productions rates that are currently unaccounted for in modern scaling schemes. Preliminary results of our deep atmosphere model show nuclide dependent attenuation lengths, therefore, altitude dependent production ratios. Preliminary results from simple, homogeneous rock planets show production rate depth profiles that diminish at a rate inconsistent with a simple exponential, the currently accepted assumption.

The University of Washington (UW) Clinical Neutron Therapy System (CNTS), which generates high linear energy transfer fast neutrons through interactions of 50.5 MeV protons incident on a Be target, has depth-dose characteristics similar to 6 MV x-rays. In contrast to the fixed beam angles and primitive blocking used in early clinical trials of neutron therapy, the CNTS has a gantry with a full 360° of rotation, internal wedges, and a multi-leaf collimator (MLC). Since October of 1984, over 3178 patients have received conformal neutron therapy treatments using the UW CNTS. In this work, the physical and dosimetric characteristics of the CNTS are documented through comparisons of measurements and Monte Carlo simulations. A high resolution computed tomography scan of the model 17 ionization chamber (IC-17) has also been used to improve the accuracy of simulations of the absolute calibration geometry. The response of the IC-17 approximates well the kinetic energy released per unit mass (KERMA) in water for neutrons and photons for energies from a few tens of keV up to about 20 MeV. Above 20 MeV, the simulated model 17 ion chamber response is 20%-30% higher than the neutron KERMA in water. For CNTS neutrons, simulated on- and off-axis output factors in water match measured values within ~2% ± 2% for rectangular and irregularly shaped field with equivalent square areas ranging in a side dimension from 2.8 cm to 30.7 cm. Wedge factors vary by less than 1.9% of the measured dose in water for clinically relevant field sizes. Simulated tissue maximum ratios in water match measured values within 3.3% at depths up to 20 cm. Although the absorbed dose for water and adipose tissue are within 2% at a depth of 1.7 cm, the absorbed dose in muscle and bone can be as much as 12 to 40% lower than the absorbed dose in water. The reported studies are significant from a historical perspective and as additional validation of a new tool for patient quality assurance and as an aid in ongoing efforts to clinically implement advanced treatment techniques, such as intensity modulated neutron therapy, at the UW.

Se describe el caso de un varón de 37 años con un linfoma primario del sistema nervioso central y con múltiples localizaciones supra e infratentoriales. El paciente presentaba manifestaciones de inflamación intraocular como expresión de su neoplasia intracraneana (síndrome de enmascaramiento) y linfocitopenia con un recuento disminuido de CD4- como representación de una inmunodeficiencia cuya etiología no logramos identificar. El diagnóstico de linfoma se confirmó a través del estudio citológico del humor vítreo. El paciente falleció 10 meses después del comienzo de los síntomas.We report the case of a 37-year-old, white male with a primary central nervous system lymphoma with multiple supra and infratentorial locations. The patient developed manifestations of intraocular inflammation secondary to the intracranial neoplasm (masquerade syndrome) and lymphocytopenia -with a low CD4 cell count- representing an immunodeficiency state which etiology was undiagnosed. The diagnosis of lymphoma was established by vitreous cytology. The patient died 10 months after the beginning of the symptoms.

Natural cosmogenic 36Cl found in seawater originates from spallation of atmospheric 40Ar, capture of secondary cosmic-ray neutrons by dissolved 35Cl, and river runoff which contains 36Cl produced in situ over the surface of the continents. The long residence time of chloride in the ocean and long half-life of 36Cl compared to the oceanic mixing time should result in a homogenous 36Cl/Cl ratio throughout the ocean. Production by neutron capture in the course of nuclear weapons testing should be insignificant averaged over the oceans as a whole, but may have led to regions of elevated 36Cl concentration. Previous attempts to measure the 36Cl/Cl ratio of seawater have been hindered by interferences, contamination, or insufficient analytic sensitivity. Here we report preliminary measurements on seawater samples, which demonstrate that the 36Cl/Cl ratio is 0.5 ± 0.3 × 10−15, in reasonable agreement with calculated contributions from the sources listed above.

Coalescence of a Maxwell viscoelastic sphere to a frictionless and flat rigid plane is analyzed to study the transition from initial elastic adhesion to viscous sintering. Deformation is driven by surface tractions due to the surface energy. The formulation for surface forces consistently combines direct van der Waals attraction across the gap ahead of the contact edge with curvature-based tractions normal to the sphere surface. These two contributions to the surface traction result in two different modes of contact growth. The initial elastic contact and the early stage of time-dependent contact growth are in a zipping mode of contact closure dominated by direct attractive forces. The later stage of sintering is by stretching of the contact and is dominated by curvature-based tractions. The transition from the initial elastic contact to the zipping mode of contact growth is viscoelastic. For a given sphere radius, kinetics of the zipping mode of contact growth scale with a characteristic viscous sinterin...

Distributed forces resulting from molecular interactions between macroscopic bodies are usually concentrated near surfaces. A new formulation has been developed that replaces these distributed body forces by effective surface tractions and is not limited by the geometrical restrictions of Derjaguin's approximation. It offers great computational simplification over the use of the body-force distribution. The body-force distribution is integrated and partitioned to various surface elements. The resulting expressions for surface traction involve a second-order tensor termed the intersurface stress tensor. It is a symmetric tensor defined for any body in terms of the intermolecular potential and the shape of the body. It acts much like the internal stress tensor; the surface traction vector on a surface introduced into its field is the inner product of the tensor and the surface normal. The new surface formulation reduces to Derjaguin's approximation for the case of a half-space with a plane surface. Properties of the new tensor are explored. Actual components are derived for several geometries.

The determination of forces resulting from molecular interactions between macroscopic bodies is important for the analysis of a variety of processes such as sintering, adhesion, and fracture. Body forces resulting from these interactions are usually concentrated near the surfaces of the bodies and are responsible for phenomena such as surface tension and surface energy. In the formulation presented here, the volume integrated intermolecular force between bodies is partitioned to obtain a distribution of effective surface tractions. This new surface formulation eliminates the geometrical restrictions associated with the commonly used Derjaguin approximation. The influence of each body on the surface of any other body is represented by a new quantity: the inter-surface stress tensor. Additional forces resulting from interactions within the body, the surface tension, have been considered for liquid-like materials. These self interactions are modeled by the classical Young-Laplace equation relating the effective traction on a surface to the energy of the surface and its curvature. The surface formulation offers considerable reduction in computational complexity compared to a formulation based on body forces. The efficacy of the technique is demonstrated using several examples.

Hamaker constants and dispersion forces interactions of materials are of increasing interest and the advent of atomic force microscopy (AFM) force measurements represents a new opportunity for quantitative studies of these interactions. A critical problem is the determination of a force–distance relation for realistic AFM probes. Due to the inadequacies of existing power‐law sphere–plane models to describe the probe–sample system, we present a new parametric tip force–distance relation (PT/FDR). A surface integration method is developed to compute the interactions between arbitrarily shaped bodies. The method is based on the Hamaker pairwise integration in a continuous fashion, reducing the six‐dimensional integration to a four‐dimensional scheme. With this method, the PT/FDR is obtained and a nonlinear fitting routine is used to extract the model parameters and the Hamaker constant from AFM force–distance data. From the sensitivity analysis of the fitting of synthesized AFM force–distance data, one finds...

A general ray-tracing method is proposed to determine the radiative properties of porous media. The particular case of random packing of equal sized spheres is studied. The method is used to calculate the forward and backward fluxes inside the medium. The two-flux model is then used to derive the absorption and scattering coefficients of the medium, from which the radiant conductivity can be calculated. Quantitative agreement is obtained in comparison with previous experimental and numerical works.

The thermal conductivity of densified random packing of spheres is studied. First, the resistance to heat flow of two touching deformed spheres is determined by the finite element method. A discrete model is proposed to extend the single contact results to random packings of spheres. The packings are densified by expanding the particle radius. Finally a continuous analytical expression is proposed to describe the relation between the effective thermal conductivity and the relative density of the packing.

Purpose: Fast neutron therapy is offered at the University of Washington Medical Center for treatment of selected cancers. The hardware and control systems of the UW Clinical Neutron Therapy System are undergoing upgrades to enable delivery of IMNT. To clinically implement IMNT, dose verification tools need to be developed. We propose a portal imaging system that relies on the creation of positron emitting isotopes (11C and 15O) through (n, 2n) reactions with a PMMA plate placed below the patient. After field delivery, the plate is retrieved from the vault and imaged using a reader that detects the annihilation photons. The pattern of activity produced in the plate provides information to reconstruct the neutron fluence map that can be compared to fluence maps from Monte Carlo (MCNP) simulations to verify treatment delivery. We have previously performed Monte Carlo simulations of the portal imaging system (GATE simulations) and the beam line (MCNP simulations). In this work, initial measurements using a prototype system are presented. Methods: Custom electronics were developed for BGO detectors read out with photomultiplier tubes (previous generation PET detectors from a CTI ECAT 953 scanner). Two detectors were placed in coincidence, with a detector separation of 2 cm. Custom software was developed to create the crystal look up tables and perform a limited angle planar reconstruction with a stochastic normalization. To test the initial capabilities of the system, PMMA squares were irradiated with neutrons at a depth of 1.5 cm and read out using the prototype system. Doses ranging from 10–200 cGy were delivered. Results: Using the prototype system, dose differences in the therapeutic range could be determined. Conclusion: The prototype portal imaging system is capable of detecting neutron doses as low as 10–50 cGy and shows great promise as a patient QA tool for IMNT.

To elaborate a nomogram based on markers of ovarian reserve for the calculation of the appropriate starting dose of follicle-stimulating hormone (FSH).Cohort study of infertile women.In vitro fertilisation (IVF) unit, University Hospital of Modena, Italy.Women aged 18-40 years (n = 346) and undergoing their first IVF cycle.Serum FSH and anti-Müllerian hormone (AMH) measurement.Development of a model for the prediction of ovarian response to FSH.A model based on age, AMH and FSH was able to accurately predict the ovarian sensitivity and accounted for 30% of the variability of ovarian response to FSH. An FSH dosage nomogram was constructed and overall it predicts a starting FSH dose225 IU in 55.1 and 25.9% of women younger and older than 35 years, respectively.In the present study we clearly demonstrated that the daily FSH dose may be calculated on the basis of a woman's age and two markers of ovarian reserve, namely AMH and FSH, with the first two vari;s (age and AMH) being the most significant predictors. The nomogram we developed seems easily applicable for clinicians during their daily clinical practice.

In this paper, a weighted directed random graph is used as network model. The graph contains a fixed number N of nodes and a variable number of edges: in particular, each edge is present with probability p. Some statistical properties (such as strong connection, global and local efficiency, cost, etc) are computed and their reliance on probability p is studied. Some probability distributions (such as shortest path, edge (node) load) are also drawn and, by using the method of stages, the best fitting curves are computed. Finally, the way as parameters characterizing such curves change when p varies is investigated.

Purpose: The University of Washington Medical Center offers neutron therapy for the palliative and definitive treatment of selected cancers. In vivo field verification has the potential to improve the safe and effective delivery of neutron therapy. We propose a portal imaging method that relies on the creation of positron emitting isotopes (11C and 15O) through (n, 2n) reactions with a PMMA plate placed below the patient. After field delivery, the plate is retrieved from the vault and imaged using a reader that detects annihilation photons. The spatial pattern of activity produced in the PMMA plate provides information to reconstruct the neutron fluence map needed to confirm treatment delivery. Methods: We used MCNP to simulate the accumulation of 11C activity in a slab of PMMA 2 mm thick, and GATE was used to simulate the sensitivity and spatial resolution of a prototype imaging system. BGO crystal thicknesses of 1 cm, 2 cm and 3 cm were simulated with detector separations of 2 cm. Crystal pitches of 2 mm and 4 mm were evaluated. Back-projection of the events was used to create a planar image. The spatial resolution was taken to be the FWHM of the reconstructed point source image. Results: Themore » system sensitivity for a point source in the center of the field of view was found to range from 58% for 1 cm thick BGO with 2 mm crystal pitch to 74% for the 3 cm thick BGO crystals with 4 mm crystal pitch. The spatial resolution at the center of the field of view was found to be 1.5 mm for the system with 2 mm crystal pitch and 2.8 mm for the system with the 4 mm crystal pitch. Conclusion: BGO crystals with 4 mm crystal pitch and 3 cm length would offer the best sensitivity reader.« less

To evaluate whether retinal arteriolar widths change in normal patients and in different glaucoma types. We measured the arteriolar width at the merge in the optic nerve (MD), at the edge of the optic nerve (ED) and at the peripapillary area (1 disc diameter distance) (disc distance D). HRT software 1.11, Interactive Means program was used. One hundred forty three eyes of seventy-two patients divided in four subgroups normal, low-tension glaucoma (LTG), primary open angle glaucoma (POAG) and ocular hypertensive (OH). No statistically significant was found in each studied group. The normal patients showed no changes in the retinal arteriolar width compared with all the glaucoma groups.

Poster: "ECR 2014 / C-1269 / Movement abnormalities in the left ventricle of Thalassemia Major patients" by: "C. Tudisca1, A. Meloni2, E. Grassedonio1, C. Argento3, G. Restaino4, G. Giannotti5, M. Lombardi2, M. Midiri1, A. Pepe2; 1Palermo/IT, 2Pisa/IT, 3Agrigento/IT, 4Campobasso/IT, 5Paterno (CT)/IT"