Galaxies in group and field environments: a comparison of optical-NIR luminosities and colors

We compare properties of galaxies in loose groups with those in field environment by analyzing the Nearby Optical Galaxy (NOG) catalog of galaxy systems. We consider as group galaxies, objects belonging to systems with at least five members identified by means of the "friends of friends method", and, as field galaxies, all galaxies with no companions. We analyze both a magnitude--limited sample of 959 and 2035 galaxies (groups vs. field galaxies, respectively, B<14 mag, and 2000<cz<6000 km/s) and a volume-limited sample (M_B <-19.01 mag, 2000<cz<4000 km/s 369 group and 548 field galaxies). For all these galaxies, blue corrected magnitudes and morphological types are available. The cross-correlation of NOG with the 2MASS second release allow us to assign K magnitudes and obtain B-K colors for about half of the galaxies in our samples. We analyze luminosity and color segregation-effects in relation with the morphological segregation. For both B and K bands, we find that group galaxies are, on average, more luminous than field galaxies and this effect is not entirely a consequence of the morphological segregation. After taking into account the morphological segregation, the luminosity difference between group and field galaxies is about 10%. When considering only very early-type galaxies (T<-2) the difference is larger than 30%. We also find that group galaxies are redder than field galaxies, Delta(B-K) about 0.4 mag. However, after taking into account the morphological segregation, we find a smaller B-K difference, poorly significant (only at the c.l. of about 80%).Comment: 11 pages, 10 eps figures, A&A in pres

EXPLORING DETECTION LIMITS AND RESPONSE TIME SCALES OF CHEMIRESISTOR GAS SENSORS BASED ON CARBON NANOTUBE AND HYBRID LAYERS

Crucial features in gas sensors for environmental monitoring are the gas sensitivity in the low ppb range and the ability to discriminate variations of a certain polluting gas from other interfering gases. Monitoring of ammonia gas concentrations is mandatory to reduce the hazard for human health and vegetation determined by the widespread use of ammonia derivatives as agricultural nitrogen fertilizers, industrial production and traffic. In particular, ammonia, besides being a toxic molecule is one of the main precursors of secondary fine particulate matter (PM10, PM2.5). Ammonia could hence be used as a local marker of secondary fine particulate formation, allowing indirect control of particulate emission sources. In spite of this urgency, the detection of NH3 concentrations in urban areas with chemiresistor gas sensors (CGSs) has been so far widely overlooked, since the average levels are usually low, i.e. in the 20-30 ppb range, while the CGSs are generally tested by exposure to ammonia in the ppm range. Carbon nanotubes (CNTs), discovered more than 20 years ago, are well known and studied systems for many applications, among which (of course) gas sensing. With respect to commercial electrochemical sensors (mostly based on metal oxide materials), CNTs show a higher physical and chemical stability, better transport of charge to the electrodes and a wide range of possible hybrid architectures and operational features, among which the operation at room temperature, that make them unique materials for gas detection. The main goal of this thesis is to increase the sensitivity to [NH3] and to lower the detection limit (DL), exploring sample preparation strategies of low-cost single walled carbon nanotubes (SWCNT)-based gas sensors operating at room temperature, considering also the response to other interfering gases. Furthermore, effects of metal oxide nanoparticles functionalization and gas response of hybrid layers have been also investigated

Precision measurements of Linear Scattering Density using Muon Tomography

We demonstrate that muon tomography can be used to precisely measure the properties of various materials. The materials which have been considered have been extracted from an experimental blast furnace, including carbon (coke) and iron oxides, for which measurements of the linear scattering density relative to the mass density have been performed with an absolute precision of 10%. We report the procedures that are used in order to obtain such precision, and a discussion is presented to address the expected performance of the technique when applied to heavier materials. The results we obtain do not depend on the specific type of material considered and therefore they can be extended to any application.Comment: 16 pages, 4 figure

AEROBIC TRAINING WITH LIMBS INTERMITTENT ISCHEMIA IMPROVES MYOCARDIAL FUNCTION AND WALL STRETCH IN PATIENTS WITH CLAUDICATION

Background: peripheral arterial disease (PAD) is a chronic disease determining functional impairment and increased risk of cardiovascular events. Physical training improves cardiac performance and reduces NTproBNP concentration, marker of risk of cardiovascular events, in cardiac patients. Aim: we aimed to examine the effects training conducted till ischemic pain at the leg of PAD patients on myocardial function and peripheral flux.Methods: we enrolled 22 patients affected by peripheral arterial disease without cardiac disease. All patients undergone a physical training of 15 days, with treadmill test at the begin and at the end of training. Results: at the end of training patients increased walking distance (450\ub1180 m vs 250\ub1108 m; p<0.05). We documented at rest, at the end of physical training, an increase in flow volume of common femoral artery of the symptomatic leg (2,55\ub12,13 L/min vs 1,86\ub11,30 L/min; p<0.05); NTproBNP concentration at rest was lower al the end of training (210\ub1130 pg/mL vs 188\ub1108 pg/mL; p<0.005), an increase of NTproBNP concentration after maximal exercise on treadmill before treatment, with a reduced increase at the end of training period (24\ub121 vs 12\ub110 pg/mL; p<0.0005); a reduction of end-diastolic diameter of left ventricle at rest (48\ub14 mm vs 50\ub15 mm; p<0.05). The ejection fraction did not changed, while heart rate reduced after training (66\ub19 bpm vs 71\ub112 bpm; p<0.05). Conclusions: this study documented an improvement of hemodynamic and cardiac performance in response of physical training in peripheral arterial disease patients not affected by cardiac disease. Further trials will be necessary to evaluate the use of NTproBNP as a marker of good response to physical training in these patients

Effects of training on reticulated reactive platelets and erytrocyte fragments in patients with peripheral atherosclerosis.

Background: training is a documented effective treatment in patients affected from peripheral arterial disease (PAD). Platelet activation plays a pivotal role in atherosclerosis progression and cardiovascular events. Reticulated platelets (IPF) reflects activity of bone marrow , recently they have been associated to cardiovascular complications and atherosclerosis with unstable conditions (e.g. acute coronary syndrome). Presence of a width blood red cell distribution is considered recently as a prognostic factor for coronary artery disease, a high RDW value depends greatly on presence of red blood cells fragmentation (FRC); this parameter may depend on different conditions such as inflammation, and oxidation and is connected with different risk factors such as hypertension and diabetes. Few data can be found for patients with peripheral arterial disease on training. We aimed to evaluate the effects of aerobic training on IPF and FRC at rest and after maximal walking exercise before and after training. Methods and Results: we enrolled 12 patients with intermittent claudication. They were submitted to a 15 days aerobic training period (cycling and treadmill exercise under maximal walking capacity). IPF, MPV, PLT count and FRC were analyzed at rest, 1 hour after maximal treadmill test and after 24 hours, these evaluations were performed at the beginning and at the end of the training period. The Lab parameters were analyzed with impedentiometry, fluorimetry (oxazyne) and optical methods (Sysmex Xn-1000, Sysmex Corporation, Kobe, Japan). Walking distance was measured with treadmill (3,2 km/h, 2-10% slope), maximal test was prolonged to the maximal tolerated claudication pain. Platelets count was within normal range (216,9 \ub1 40 109/l ) and did not changed throughout the study; also MPV was unchanged (11,6\ub11,9 vs 11.45\ub10,8 fl ) before and after the training ; plateletcrit was slightly reduced (0,246\ub10,061 vs 0,282 \ub10,018 %). IPF count (figure) slightly changed during maximal stress at the beginning of training with increase after 24 hours; after training the count decreased significantly (*p<0,05) at rest and 1 hour after, while it increased significantly after 24 hours (** p<0,05 vs rest ad vs 24 h-pre) but less than before training. FRC decreased after triaining (0,381\ub10,121 vs 0,542\ub10,220 %; p<0,05), maximal test slightly increased FRC after 1 hour , no significant change after 24 hours. At the end of training, absolute walking distance increased (450\ub1180 vs 250\ub1108 m; p<0,05). Discussion: training reduces IPF in patients with peripheral arterial disease, IPF increase after acute maximal test and this phenomenon can be attenuated by training. We also observed a reduction in FRC. Presence of FRC in these patients may be caused by mechanical forces throughout a large surface of atherosclerotic plaques fragmenting red cells, ischemia reperfusion in claudication is another mechanism that can elicit formation of FRC and in addition high oxidative stress may contribute. IPF are associated with an increase platelets activity and a higher turnover; in this pathology both these condition can be found associated with oxidative stress, inflammation and endothelial dysfunction. Training improves oxidation, inflammation and endothelium function with favorable effects on platelets activation and turnover, furthermore these parameters may influence also FRC count. Conclusion: training in PAD patients reduces IPF and FRC with potential improvement in risk profile for atherosclerosis progression and reduction of cardiovascular events. References: 1. Cesari F, Marcucci R, Gori AM, et al . Reticulated platelets predict cardiovascular death in acute coronary syndrome patients. Thrombosis and Haemostasis 2013; 109: 846-853. 2. Hoffmann JJ . Reticulated platelets: analytical aspects and clinical utility. Clin Chem Lab. 2014; 52: 1107-17. 3. Bujak K, Wasilewski J, Osadnik T, et al. Prognostic role of red blood cell distribution width in coronary artery disease: a review of the pathophysiology. Disease Markers 2015, vol 1 ; 1-12

Supervised training improves endothelial function measured during induced ischemia in peripheral arterial disease.

Introduction: favorable effect of training on cardiovascular pathology is well documented in literature. Mechanisms evoked are the following: increased NO availability for reduction of oxidative stress, inflammation decrease, improvement of glucidic and lipidic metabolism, resetting of neuro-endocrine balance (1). These mechanism are also involved in the improvement of patients with peripheral arterial disease (PAD) treated with training. PAD is a model of inducible ischemia, in fact claudication is a condition in which ischemia/reperfusion phenomenon is present when walking is conducted till maximum pain (2). This phenomenon may produce a great amount of radical oxygen species with possible consequence on endothelium function. Xanthine oxidase is one of the most relevant enzyme involved in this process. Different types of training are proposed for PAD patients and there is not a consensus whether the ischemic pain should be reached during exercise. So we aimed to verify if maximal treadmill test (till pain) causes endothelial dysfunction, if oxidative stress is acutely aroused and if xanthine oxidase is involved. Therefore we aimed to verify if a training performed under the onset of ischemic pain can improve endothelial function ether at rest and after maximum tolerated exercise. Patients and methods: we enrolled 20 patients with PAD (16 males, 4 females, aged 65-77). Endothelium dependent dilation (EDD) was measured at humeral artery by ultrasound method, before and after maximal treadmill test (speed 3,2 km/h; slope 10%). We administered allopurinol 600 mg the day before and 600 mg 6 hours before a new treadmill test. Serum uric acid and lactate were determined throughout the study. Afterwards patients performed supervised training under pain onset for 20 days with physiotherapist overview. Every 7 days a new treadmill test was performed for updating training distance. At the end of the training period EDD was measured before and after a maximal treadmill test. Furthermore microcirculatory endothelium dependent dilation was measured at the skin of the forefoot by means of laser-Doppler (LD) after iontophoretic acetylcholine administration. Results: maximal treadmill test acutely reduced EDD (6,1\uf0b10,7 vs 9,2\uf0b10,9 %; p<0,05;). Allopurinol improved EDD (10,1\uf0b10,3 vs 9,4\uf0b10,6 %; p<0,05) with a reduced fall after maximal test (delta decrease -21,3\uf0b12,2 vs \u201333,2\uf0b11,2%; p<0,05). Training increased pain free walking distance (131\uf0b112 vs 66,6\uf0b121 m; p<0,05) and absolute walking distance (275\uf0b115 vs 125,8\uf0b140 m; p<0,05). EDD improved after training period (11,3\uf0b10,7 vs 9,2\uf0b10,9; p<0,05). The fall in EDD, observed during maximal treadmill test at the end of training period, was smaller than the one measured before training (delta decrease -15,5\uf0b12,4 vs \u201333,2\uf0b11,2%; p<0,005). Microcirculatory endothelium dependent dilation measured with LD increased after training (table). Table: microcirculatory flux with LD after iontophoretic acetylcholine. Acetylcholine 0,10 mA 10 s 20 s 40 s T 0 (% incr) 35\uf0b19 70\uf0b115 120\uf0b115 T 20 (%incr) 147\uf0b138* 182\uf0b122* 470\uf0b154* (*p<0.005 T20 vs T0) Conclusions: we demonstrate that walking through maximal pain causes impairment of EDD, this is caused by oxidative stress and can be reduced by inhibition of xanthine oxidase. Aerobic training improves EDD and microcirculatory endothelial function, furthermore training reduces the drop of EDD during maximal exercise and increased oxidative stress. As a consequence these results suggest the training should be performed under the maximal pain. References 1. Brendle DC, Joseph LJ, Corretti MC, Gardner AW, Katzel LI. Effects of exercise rehabilitation on endothelial reactivity in older patients with peripheral arterial disease. Am J Cardiol 2001;87:324-9. 2. Andreozzi GM, Leone A, Laudani R, Deinite G, Martini R. Acute impairment of the endothelial function by maximal treadmill exercise in patients with intermittent claudication, and its improvement after supervised physical training. Int Angiol. 2007; 26:12-7

Nanoscale characterization of an all-oxide core-shell nanorod heterojunction using intermodulation atomic force microscopy (AFM) methods

The electrical properties of an all-oxide core-shell ZnO-Co3O4nanorod heterojunction were studied in the dark and under UV-vis illumination. The contact potential difference and current distribution maps were obtained utilizing new methods in dynamic multifrequency atomic force microscopy (AFM) such as electrostatic and conductive intermodulation AFM. Light irradiation modified the electrical properties of the nanorod heterojunction. The new techniques are able to follow the instantaneous local variation of the photocurrent, giving a two-dimensional (2D) map of the current-voltage curves and correlating the electrical and morphological features of the heterostructured core-shell nanorods

Microwave driven synthesis of narrow bandgap alpha-tin nanoparticles on silicon

This work proposes a microwave-based synthetic route for the preparation of tin nanospheres with a diamond-like a-phase structure on silicon. The main characteristics of the synthesized material are an extraordinarily narrow (around 50 meV) direct bandgap and an improved thermal stability (up to 200° C). Structural and compositional characterizations showed a core–shell structure comprised of an outer amorphous oxide shell and inner core containing a-phase tin domains. Microwaves turned out to be instrumental in achieving the specific nanostructures reported, due to their peculiar heating characteristics. Low pressure, low temperature and compatibility with integrated circuits manufacturing represent the most innovative features of the present synthetic process

A CXCR4 receptor agonist strongly stimulates axonal regeneration after damage

Objective: To test whether the signaling axis CXCL12\u3b1-CXCR4 is activated upon crush/cut of the sciatic nerve and to test the activity of NUCC-390, a new CXCR4 agonist, in promoting nerve recovery from damage. Methods: The sciatic nerve was either crushed or cut. Expression and localization of CXCL12\u3b1 and CXCR4 were evaluated by imaging with specific antibodies. Their functional involvement in nerve regeneration was determined by antibody-neutralization of CXCL12\u3b1, and by the CXCR4 specific antagonist AMD3100, using as quantitative read-out the compound muscle action potential (CMAP). NUCC-390 activity on nerve regeneration was determined by imaging and CMAP recordings. Results: CXCR4 is expressed at the injury site within the axonal compartment, whilst its ligand CXCL12\u3b1 is expressed in Schwann cells. The CXCL12\u3b1-CXCR4 axis is involved in the recovery of neurotransmission of the injured nerve. More importantly, the small molecule NUCC-390 is a strong promoter of the functional and anatomical recovery of the nerve, by acting very similarly to CXCL12\u3b1. This pharmacological action is due to the capability of NUCC-390 to foster elongation of motor neuron axons both in vitro and in vivo. Interpretation: Imaging and electrophysiological data provide novel and compelling evidence that the CXCL12\u3b1-CXCR4 axis is involved in sciatic nerve repair after crush/cut. This makes NUCC-390 a strong candidate molecule to stimulate nerve repair by promoting axonal elongation. We propose this molecule to be tested in other models of neuronal damage, to lay the basis for clinical trials on the efficacy of NUCC-390 in peripheral nerve repair in humans