The LUNA-MV facility at Gran Sasso Prati, Paolo
Journal of physics. Conference series,
01/2020, Letnik:
1342, Številka:
1
Journal Article
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About 25 year ago LUNA (laboratory for Underground Nuclear Astrophysics) opened the era of underground nuclear astrophysics installing a home-made 50 kV ion accelerator under the Gran Sasso mountain. ...A second machine, with a terminal voltage of 400 kV, was then installed and it is still in operation. Most of the processes so far investigated were connected to the physics of solar neutrinos and hence to the hydrogen burning phase in stars. The interest in next and warmers stages of star evolution (i.e. helium and carbon burning) pushed a new project based on an ion accelerator in the MV range called LUNA-MV. Thanks to a special grant of the Italian Ministry of Research (MIUR), INFN is now building, inside one of the major halls at Gran Sasso, a new facility which will host a 3.5 MV single-ended accelerator able to deliver proton, helium and carbon beams with intensity in the mA range.
The aim of experimental nuclear astrophysics is to provide information on the nuclear processes involved in astrophysical scenarios at the relevant energy range. However, the measurement of the cross ...section of nuclear reactions at low energies present formidable difficulties due to the very low reaction rates often overwhelmed by the background. Several approaches have been proposed and exploited to overcome such severe obstacles: in such frame, the idea to install a low energy - high intensity ion accelerator deep underground, to gain high luminosity while reducing the cosmic ray background, brought more than 25 years ago, to the pilot LUNA experiment. LUNA stands for Laboratory for Underground Nuclear Astrophysics: in the cave under the Gran Sasso mountain (in Italy) first a 50 kV and then a 400 kV single-ended accelerator for protons and alphas were deployed and produced plenty of data mainly on reactions of the H-burning phase in stars. Recently, similar facilities have been installed and/or proposed in other underground laboratories in US and China. LUNA as well is going to make a big step forward, with a new machine in the MV range which will be able to provide intense beams of protons, alphas and carbon ions. The rationale of underground nuclear astrophysics will be presented together with the last updates on the ongoing research programs.
This paper analyses elemental (EC), organic (OC) and total carbon (TC) concentration in PM2.5 and PM10 samples collected over the last few years within several national and European projects at 37 ...remote, rural, urban, and traffic sites across the Italian peninsula.
The purpose of the study is to obtain a picture of the spatial and seasonal variability of these aerosol species in Italy, and an insight into sources, processes and effects of meteorological conditions.
OC and EC showed winter maxima and summer minima at urban and rural locations and an opposite behaviour at remote high altitude sites, where they increase during the warm period due to the rising of the Planetary Boundary Layer (PBL). The seasonal averages of OC are higher during winter compared to summer at the rural sites in the Po Valley (from 1.4 to 3.5 times), opposite to what usually occurs at rural locations, where OC increases during the warm period. This denotes the marked influence of urban areas on the surrounding rural environment in this densely populated region.
The different types of sites exhibit marked differences in the average concentrations of carbonaceous aerosol and OC/EC ratio. This ratio is less sensitive to atmospheric processing than OC and EC concentrations, and hence more representative of different source types. Remote locations are characterised by the lowest levels of OC and especially EC, with OC/EC ratios ranging from 13 to 20, while the maximum OC and EC concentrations are observed at road-traffic influenced urban sites, where the OC/EC ratio ranges between 1 and 3. The highest urban impacts of OC and EC relative to remote and rural background sites occur in the Po Valley, especially in the city of Milan, which has the highest concentrations of PM and TC and low values of the OC/EC ratio.
•We compared OC and EC data from different sites across the Italian Peninsula.•OC and EC concentration maxima occur during winter and minima during summer at all except remote sites.•Higher OC levels characterize the Po Valley compared to the rest of Italy both during summer and winter.•Biomass burning for residential heating strongly affects winter OC concentrations in the Po Valley.•Carbonaceous matter contribution to PM2.5 ranges between 37% at rural and 47% at traffic sites, on an annual basis.
Cryoconite, the typical sediment found on the surface of glaciers, is mainly known in relation to its role in glacial microbiology and in altering the glacier albedo. But if these aspects are ...relatively well addressed, the same cannot be said about the geochemical properties of cryoconite and the possible interactions with glacial and peri-glacial environment. Current glacier retreat is responsible for the secondary emission of species deposited in high-altitude regions in the last decades. The role played by cryoconite in relation to such novel geochemical fluxes is largely unknown. Few and scarce observations suggest that it could interact with these processes, accumulating specific substances, but why, how and to what extent remain open questions. Through a multi-disciplinary approach we tried to shed lights. Results reveal that the peculiar composition of cryoconite is responsible for an extreme accumulation capability of this sediment, in particular for some, specific, anthropogenic substances.
In post-stroke patients with equinovarus foot deformity (EVFD), soft tissue rearrangements may contribute to muscle overactivity when a muscle is stretched or tension is applied. Therefore, we ...investigated the effects of surgically restoring the triceps surae (TS) length and lengthening ability on TS spasticity.
This retrospective study included chronic post-stroke patients who underwent neuro-orthopedic surgery inclusive of TS lengthening. TS spasticity was measured using the Modified Tardieu Scale (MTS) before and 1 month after surgery, both with the knee extended (KE) and flexed (KF). MTS variations were analyzed using the Wilcoxon test. The time from stroke onset was compared between patients with and without post-surgical spasticity using the
-test. Statistical significance was set at 5%.
A total of 120 patients with EVFD, aged 57 (12) years, ranging from 1 to 36 years from stroke, were included in the study. The median MTS_KE score significantly decreased from 3 (range 0-4) to 2 (0-4) (
< 0.001) after surgery. The MTS score decreased by ≥1 point in more than half of the sample. Notably, 19 and 32 patients were completely relieved from spasticity (MTS = 0) in the KE and KF conditions, respectively. Post-surgical spasticity did not depend on the time since stroke onset (
= 0.560).
TS lengthening led to a short-term reduction of spasticity in 41% and 63% of chronic post-stroke patients in the gastro-soleus complex and soleus, respectively, with complete relief observed in 21% and 30% of the sample. Surgical lengthening can be considered an effective treatment that not only restores joint range of motion but also may reduce spasticity, even in chronic patients.
This paper presents new laboratory measurements of the mass absorption efficiency (MAE) between 375 and 850 nm for 12 individual samples of mineral dust from different source areas worldwide and in ...two size classes: PM10. 6 (mass fraction of particles of aerodynamic diameter lower than 10.6 µm) and PM2. 5 (mass fraction of particles of aerodynamic diameter lower than 2.5 µm). The experiments were performed in the CESAM simulation chamber using mineral dust generated from natural parent soils and included optical and gravimetric analyses. The results show that the MAE values are lower for the PM10. 6 mass fraction (range 37–135 × 10−3 m2 g−1 at 375 nm) than for the PM2. 5 (range 95–711 × 10−3 m2 g−1 at 375 nm) and decrease with increasing wavelength as λ−AAE, where the Ångström absorption exponent (AAE) averages between 3.3 and 3.5, regardless of size. The size independence of AAE suggests that, for a given size distribution, the dust composition did not vary with size for this set of samples. Because of its high atmospheric concentration, light absorption by mineral dust can be competitive with black and brown carbon even during atmospheric transport over heavy polluted regions, when dust concentrations are significantly lower than at emission. The AAE values of mineral dust are higher than for black carbon (∼ 1) but in the same range as light-absorbing organic (brown) carbon. As a result, depending on the environment, there can be some ambiguity in apportioning the aerosol absorption optical depth (AAOD) based on spectral dependence, which is relevant to the development of remote sensing of light-absorbing aerosols and their assimilation in climate models. We suggest that the sample-to-sample variability in our dataset of MAE values is related to regional differences in the mineralogical composition of the parent soils. Particularly in the PM2. 5 fraction, we found a strong linear correlation between the dust light-absorption properties and elemental iron rather than the iron oxide fraction, which could ease the application and the validation of climate models that now start to include the representation of the dust composition, as well as for remote sensing of dust absorption in the UV–vis spectral region.
Introduction
Charcot-Marie-Tooth disease (CMT) is a slow and progressive peripheral motor sensory neuropathy frequently associated with the cavo-varus foot deformity. We conducted a scoping review on ...the clinical scales used to assess foot deviations in CMT patients and analyzed their metric properties.
Evidence Acquisition
A first search was conducted to retrieve all scales used to assess foot characteristics in CMT patients from the Medline, Web of Science, Google Scholar, Cochrane, and PEDro databases. A second search was conducted to include all studies that evaluated the metric properties of such identified scales from the same databases. We followed the methodologic guidelines specific for scoping reviews and used the PICO framework to set the eligibility criteria. Two independent investigators screened all papers.
Evidence Synthesis
The first search found 724 papers. Of these, 41 were included, using six different scales: “Foot Posture Index” (FPI), “Foot Function Index”, “Maryland Foot Score”, “American Orthopedic Foot & Ankle Society's Hindfoot Evaluation Scale”, “Foot Health Status Questionnaire”, Wicart-Seringe grade. The second search produced 259 papers. Of these, 49 regarding the metric properties of these scales were included. We presented and analyzed the properties of all identified scales in terms of developmental history, clinical characteristics (domains, items, scores), metric characteristics (uni-dimensionality, inter- and intra-rater reliability, concurrent validity, responsiveness), and operational characteristics (normative values, manual availability, learning time and assessors' characteristics).
Conclusions
Our results suggested the adoption of the six-item version of the FPI scale (FPI-6) for foot assessment in the CMT population, with scoring provided by Rasch Analysis. This scale has demonstrated high applicability in different cohorts after a short training period for clinicians, along with good psychometric properties. FPI-6 can help health professionals to assess foot deformity in CMT patients over the years.
Patients with Charcot-Marie-Tooth disease (CMT) often suffer from walking-related pain (WRP), muscle weakness, foot deformities, and reduced ankle dorsiflexion (DF), which affects their ability to ...walk and daily activities. Functional surgery (FS) can restore foot deviations, affecting the loading ability during gait. We assessed the short-term effects of FS in patients with CMT on WRP, foot and ankle structure, and function, along with patients' perceived improvement.
This is a prospective cohort study on CMT patients who had undergone FS and rehabilitation. We analyzed the changes after 1 month, focusing on WRP, DF, the center of pressure progression (COPP) during walking, and measures of walking ability. The non-parametric Wilcoxon test was used.
Ten patients were included. One month after FS, WRP reduced from 5.5 (IQR = 3.5) to 2 (IQR = 3.5),
= 0.063, with an effect size of 0.615. The highest decrease was found in patients with very high pre-surgical pain levels. DF almost reached 10° for both active and passive movements (
< 0.05), and COPP improved from 44 to 60% (
= 0.009) of foot length. Gait speed, lower limb functioning, and balance did not change. More than half of the sample felt improved or much improved after FS.
FS can be effective in reducing WRP and restoring foot posture in CMT patients in the short-term, which allows them to wear shoes, and leads to a perceived improvement and satisfaction. Lack of improvement in functional skills may be due to muscle weakness typical of CMT. Studies with longer follow-ups may confirm these hypotheses.
Background
Muscle overactivity is one of the positive signs of upper motor neuron lesions. In these patients, the loss of muscle length and extensibility resulting from soft tissue rearrangement has ...been suggested as a contributing cause of muscle overactivity in response to stretching.
Objective
To assess the effects of surgical lengthening of the quadriceps femoris (QF) muscle-tendon unit by aponeurectomy on muscle spasticity.
Methods
This is a case-control study on chronic stroke patients with hemiparesis that have undergone lower limb functional surgery over a 8-year period. CASEs underwent corrective surgery for both the foot and knee deviations, inclusive of a QF aponeurectomy. Controls (CTRLs) underwent corrective surgery for foot deviations only. QF spasticity was assessed with the Modified Tardieu Scale (MTS) before and 1 month after surgery. The Wilcoxon test was used to assess MTS variations over time and the Mann–Whitney test was used to verify the presence of group differences at the 1 month mark.
Results
Ninety-three patients were included: 57 cases (30F, 1–34 years from lesion) and 36 controls (12F, 1–35 years from lesion). Before surgery, both CASEs and CTRLs had similar MTS scores (median MTS = 3) and functional characteristics. One month after surgery, QF spasticity was significantly lower in the CASEs compared to CTRLs (
p
= 0.033) due to a significant reduction of the median MTS score from 3 to 0 in the CASE group (
p
< 0.001) and no variations in the CTRL group (
p
= 0.468). About half of the cases attained clinically significant MTS reductions and complete symptom relief even many years from the stroke.
Conclusions
Functional surgery inclusive of QF aponeurectomy can be effective in reducing or suppressing spasticity in chronic stroke patients. This is possibly a result of the reduction in neuromuscular spindle activation due to a decrease in muscle shortening, passive tension, and stiffness.
In literature, indices of overall walking ability that are based on ground reaction forces have been proposed because of their ease of administration with patients. In this study, we analyzed the ...correlation between the indices of dynamic loading and propulsion ability of 40 chronic hemiparetic post-stroke patients with equinus foot deviation and a set of clinical assessments of ankle joint deviations and walking ability. Ankle passive and active range of motion (ROM) and triceps surae spasticity were considered, along with walking speed and three complementary scales of walking ability focusing respectively on the need for assistance on functional mobility, including balance and transfers, and the limitation in social participation. The correlation between the ground reaction force-based indices and both clinical and functional variables was carried out using the non-parametric Spearman correlation coefficient. Both indices were correlated to 8 of the 10 investigated variables, thus supporting their use. In particular, the dynamic propulsive ability was correlated with all functional scales (rho = 0.5,
< 0.01), and has the advantage of being a continuous variable. Among clinical assessments, limited ankle ROM affected walking ability the most, while spasticity did not. Since the acquisition of ground reaction forces does not require any patient prepping, the derived indices can be used during the rehabilitation period to quickly detect small improvements that, over time, might lead to the broad changes detectable by clinical scales, as well as to immediately highlight the lack of these improvements, thus suggesting adjustments to the ongoing rehabilitation approach.
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