126 research outputs found
Logic functions, devices, and circuits based on parametric nonlinear processes
Second-harmonic generation and parametric down-conversion processes have been studied as the basis of all-optical logic gates. All possibilities that are obtainable with both the low and high conversion efficiencies of such processes have been analyzed here. XOR and AND gates are also experimentally proven by using 1-ps pulses at 800 nm within a beta-BaB(2)O(4) crystal, reaching conversion efficiencies of as high as 80%. Based on these phenomena, complex algebraic operations are proposed for performing several different logic functionalities particularly concerning network switching and arithmetic calculation
From Agri-Food Wastes to Polyhydroxyalkanoates through a Sustainable Process
The biologically-derived polymers polyhydroxyalkanoates (PHAs) are biodegradable and can be considered a valuable alternative to conventional fossil-based plastics. However, upstream and downstream processes for PHA production are characterized by high energy and chemical consumption and are not economically competitive with petroleum-based polymers. Aiming to improve both the environmental and economical sustainability of PHAs production, in this work, corn straw was used as raw material to obtain a mixture of fermentable sugars after microwave-assisted flash hydrolysis (2 min, 0.01 g/L, 50.7% yield). A mixed microbial culture enriched from dairy industry waste was used for fermentation in a shake flask, allowing us to achieve good poly(hydroxy-butyrate-co-hydroxy-valerate) yields (41.4%, after 72 h of fermentation). A scale-up in a stirred tank bioreactor (3 L) gave higher yields (76.3%, after 96 h), allowing in both cases to achieve a concentration of 0.42 g/L in the fermentation medium. The possibility of producing PHAs from agricultural waste using a mixed microbial culture from the food industry with enabling technologies could make the production of biopolymers more competitive
Experimental results of the laserwire emittance scanner for LINAC4 at CERN
Within the framework of the LHC Injector Upgrade (LIU), the new LINAC4 is
currently being commissioned to replace the existing LINAC2 proton source at
CERN. After the expected completion at the end of 2016, the LINAC4 will
accelerate H- ions to 160 MeV. To measure the transverse emittance of the H-
beam, a method based on photo-detachment is proposed. This system will operate
using a pulsed laser with light delivered via an optical fibre and subsequently
focused through a thin slice of the H- beam. The laser photons have sufficient
energy to detach the outer electron and create H0/e- pairs. In a downstream
dipole, the created H0 particles are separated from the unstripped H- ions and
their distribution is measured with a dedicated detector. By scanning the
focused laser across the H- beam, the transverse emittance of the H- beam can
be reconstructed. This paper will first discuss the concept, design and
simulations of the laserComment: Presented at the International Conference on Laser Applications at
Accelerators, LA3NET 2015; Submitted to Nucl. Instr. and Meth. in Phys. Res.
section
Early putamen hypertrophy and ongoing hippocampus atrophy predict cognitive performance in the first ten years of relapsing-remitting multiple sclerosis
Background
The first years of relapsing-remitting multiple sclerosis (RRMS) constitute the most vulnerable phase for the progression of cognitive impairment (CImp), due to a gradual decrease of compensatory mechanisms. In the first 10 years of RRMS, the temporal volumetric changes of deep gray matter structures must be clarified, since they could constitute reliable cognitive biomarkers for diagnostic, prognostic, and therapeutic purposes.
Methods
Forty-five cognitively asymptomatic patients with RRMS lasting 64\u200910 years, and with a brain MRI performed in a year from the neuropsychological evaluation (Te-MRI), were included. They performed the Brief International Cognitive Assessment battery for MS. Thirty-one brain MRIs performed in the year of diagnosis (Td-MRI) and 13 brain MRIs of age- and sex-matched healthy controls (HCs) were also included in the study. The relationships between clinical features, cognitive performances, and Te- and Td-MRI volumes were statistically analyzed.
Results
Cognitively preserved (CP) patients had significantly increased Td-L-putamen (P\u2009=\u20090.035) and Td-R-putamen volume (P\u2009=\u20090.027) with respect to cognitively impaired (CI) ones. CI patients had significantly reduced Te-L-hippocampus (P\u2009=\u20090.019) and Te-R-hippocampus volume (P\u2009=\u20090.042) compared, respectively, with Td-L-hippocampus and Td-R-hippocampus volume. Td-L-putamen volume (P\u2009=\u20090.011) and Te-L-hippocampus volume (P\u2009=\u20090.023) were independent predictors of the Symbol Digit Modalities Test score in all patients (r2\u2009=\u20090.31, F\u2009=\u20096.175, P\u2009=\u20090.001).
Conclusion
In the first years of RRMS, putamen hypertrophy and hippocampus atrophy could represent promising indices of cognitive performance and reserve, and become potentially useful tools for diagnostic, prognostic, and therapeutic purposes
Fatigue in Multiple Sclerosis: a resting-state EEG microstate study
Fatigue affects approximately 80% of people with Multiple Sclerosis (PwMS) and can impact several domains of daily life. However, the neural underpinnings of fatigue in MS are still not completely clear. The aim of our study was to investigate the spontaneous large-scale networks functioning associated with fatigue in PwMS using the EEG microstate approach with a spectral decomposition. Forty-three relapsing-remitting MS patients and twenty-four healthy controls (HCs) were recruited. All participants underwent an administration of Modified Fatigue Impact scale (MFIS) and a 15-min resting-state high-density EEG recording. We compared the microstates of healthy subjects, fatigued (F-MS) and non-fatigued (nF-MS) patients with MS; correlations with clinical and behavioral fatigue scores were also analyzed. Microstates analysis showed six templates across groups and frequencies. We found that in the F-MS emerged a significant decrease of microstate F, associated to the salience network, in the broadband and in the beta band. Moreover, the microstate B, associated to the visual network, showed a significant increase in fatigued patients than healthy subjects in broadband and beta bands. The multiple linear regression showed that the high cognitive fatigue was predicted by both an increase and decrease, respectively, in delta band microstate B and beta band microstate F. On the other hand, higher physical fatigue was predicted with lower occurrence microstate F in beta band. The current findings suggest that in MS the higher level of fatigue might be related to a maladaptive functioning of the salience and visual network
rTMS over the human medial parietal cortex impairs online reaching corrections
Indirect correlational evidence suggests that the posteromedial sector of the human parietal cortex (area hV6A) is involved in reaching corrections. We interfered with hV6A functions using repetitive transcranial magnetic stimulation (rTMS) while healthy participants performed reaching movements and in-flight adjustments of the hand trajectory in presence of unexpected target shifts. rTMS over hV6A specifically altered action reprogramming, causing deviations of the shifted trajectories, particularly along the vertical dimension (i.e., distance). This study provides evidence of the functional relevance of hV6A in action reprogramming while a sudden event requires a change in performance and shows that hV6A also plays a role in state estimation during reaching. These findings are in line with neurological data showing impairments in actions performed along the distance dimension when lesions occur in the dorsal posterior parietal cortex
Thyroglobulin measurement in the washout of fine needle aspirates for the diagnosis of suspicious cervical lymph nodes
Ultrasound-guided fine-needle aspiration cytology (FNAC) for suspicious cervical lymph nodes (CLN) is the gold standard technique for the identification of metastases from differentiated thyroid carcinomas. Thyroglobulin protein (Tgp) assay in the washout of needles employed for FNA biopsies (FNAB) has been reported to refine and support FNAC performances, especially in cases of inadequate sampling or cystic lymph nodes. In the present work, we evaluated the usefulness of routine measurement of Tgp in the FNAB washout of suspicious cervical lymph nodes (CLN), and its ability to increase the FNAC accuracy in the diagnosis of metastatic CLN.
A case study of 45 CLN with histological diagnosis from 36 patients was analyzed. Histology showed metastases from papillary thyroid carcinomas (PTC) in 31 CLN, from anaplastic thyroid cancer (ATC) in 3 CLN, from medullary thyroid cancer (MTC) in 4 CLN, and metastases from extrathyroidal malignancies in 5 CLN. Two CLN analyzed were found to be non-neoplastic.
The overall accuracy of FNAC was 82.9%, and that of Tgp was 91.1%, not statistically different. However, Tgp determination was found essential in 4 cases of metastatic CLN from DTC with inadequate cytology, and in 1 case in which the FNAC provided a false negative result.
We demonstrated that FNAC and Tgp assay show similar diagnostic accuracies, and that Tgp measurement may represent the only available information in case of inadequate lymph node sampling or cystic lymph nodes
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