Minimum-Variance Importance-Sampling Bernoulli Estimator for Fast Simulation of Linear Block Codes over Binary Symmetric Channels

In this paper the choice of the Bernoulli distribution as biased distribution for importance sampling (IS) Monte-Carlo (MC) simulation of linear block codes over binary symmetric channels (BSCs) is studied. Based on the analytical derivation of the optimal IS Bernoulli distribution, with explicit calculation of the variance of the corresponding IS estimator, two novel algorithms for fast-simulation of linear block codes are proposed. For sufficiently high signal-to-noise ratios (SNRs) one of the proposed algorithm is SNR-invariant, i.e. the IS estimator does not depend on the cross-over probability of the channel. Also, the proposed algorithms are shown to be suitable for the estimation of the error-correcting capability of the code and the decoder. Finally, the effectiveness of the algorithms is confirmed through simulation results in comparison to standard Monte Carlo method

Low-complexity dominance-based Sphere Decoder for MIMO Systems

The sphere decoder (SD) is an attractive low-complexity alternative to maximum likelihood (ML) detection in a variety of communication systems. It is also employed in multiple-input multiple-output (MIMO) systems where the computational complexity of the optimum detector grows exponentially with the number of transmit antennas. We propose an enhanced version of the SD based on an additional cost function derived from conditions on worst case interference, that we call dominance conditions. The proposed detector, the king sphere decoder (KSD), has a computational complexity that results to be not larger than the complexity of the sphere decoder and numerical simulations show that the complexity reduction is usually quite significant

Anesthesia for off-pump coronary artery bypass surgery

The evolution of techniques and knowledge of beating heart surgery has led anesthesia toward the development of new procedures and innovations to promote patient safety and ensure high standards of care. Off-pump coronary artery bypass (OPCAB) surgery has shown to have some advantages compared to on-pump cardiac surgery, particularly the reduction of postoperative complications including systemic inflammation, myocardial injury, and cerebral injury. Minimally invasive surgery for single vessel OPCAB through a limited thoracotomy incision can offer the advantage of further reduction of complications. The anesthesiologist has to deal with different issues, including hemodynamic instability and myocardial ischemia during aorto-coronary bypass grafting. The anesthesiologist and surgeon should collaborate and plan the best perioperative strategy to provide optimal care and ensure a rapid and complete recovery. The use of high thoracic epidural analgesia and fast-track anesthesia offers particular benefits in beating heart surgery. The excellent analgesia, the ability to reduce myocardial oxygen consumption, and the good hemodynamic stability make high thoracic epidural analgesia an interesting technique. New scenarios are entering in cardiac anesthesia: ultra-fast-track anesthesia with extubation in the operating room and awake surgery tend to be less invasive, but can only be performed on selected patients

Peripheral Biomarkers in Manifest and Premanifest Huntington’s Disease

Huntington's disease (HD) is characterized by clinical motor impairment (e.g., involuntary movements, poor coordination, parkinsonism), cognitive deficits, and psychiatric symptoms. An inhered expansion of the CAG triplet in the huntingtin gene causing a pathogenic gain-of-function of the mutant huntingtin (mHTT) protein has been identified. In this review, we focus on known biomarkers (e.g., mHTT, neurofilament light chains) and on new biofluid biomarkers that can be quantified in plasma or peripheral blood mononuclear cells from mHTT carriers. Circulating biomarkers may fill current unmet needs in HD management: better stratification of patients amenable to etiologic treatment; the initiation of preventive treatment in premanifest HD; and the identification of peripheral pathogenic central nervous system cascades

High temperature heat treatment of B precursor and P.I.T. process optimization to increase Jc performances of MgB2-based conductor

Promising results reported in our previous works led us to think that production of B powder plays a crucial role in MgB2 synthesis. A new method for boron preparation has been developed in our laboratory. This particular process is based on magnesiothermic reaction (Moissan process) with the addition of an initial step that gives boron powder with nano-metric grain size. In this paper we report our efforts regarding optimization of PIT method for these nanometric powders and the resolution of problems previously highlighted such as the difficulty in powder packaging and the high friction phenomena occurring during cold working. This increases cracking during the tape and wire manufacturing leading to its failure. Packaging problems are related to the amorphous nature of boron synthesized in our laboratory, so a crystallization treatment was applied to improve crystallinity of B powder. To prevent excessive friction phenomena we synthesized non-stoichiometric MgB2 and using magnesium as lubricant. Our goal is the Jc improvement, but a global physical-chemical characterization was also made to analyze the improvement given by our treatments: this characterization includes X-ray diffraction, resistivity vs. temperature measurement, SEM image, besides magnetic and transport Jc measurements.Comment: 15 pages, 11 figure

Grain size determination of superconducting MgB2 powders from magnetization curve, image analysis and surface area measurement

The present article reports a method for the average grain size evaluation of superconducting nano-particles through their magnetic properties. The use of SQUID magnetometry to determine the average MgB2 particle size was investigated and the results compared with those achieved through other techniques. In particular the data obtained from zero field cooled magnetization measurement as function of the temperature were compared with the results obtained by scanning electron microscopy and Brunauer-Emmett-Teller techniques. The particle magnetization was measured by a commercial SQUID magnetometer in magnetic field (1 mT) and temperatures ranging from 5 to 50 K dispersing the powders in a grease medium. The grain size is obtained by fitting the data taking into account the Ginzburg-Landau temperature dependence of the London penetration depth. Variations on typical modeling parameters were explored in order to gain a better picture of the average grain size and the effectiveness of various measurement techniques. We find that it is possible to use the magnetization measurements to determine the average grain size even if the SEM image analysis allows extracting more information about the grain size distribution. Furthermore a Matlab routine has been developed in order to get automatic analysis of SEM images.Comment: 12 pages, 10 figures, 5 table

GWAS-associated Variants, Non-genetic Factors, and Transient Transcriptome in Multiple Sclerosis Etiopathogenesis: a Colocalization Analysis [preprint]

A clinically actionable understanding of multiple sclerosis (MS) etiology goes through GWAS interpretation, prompting research on new gene regulatory models. Our previous works on these topics suggested a stochastic etiologic model where small-scale random perturbations could eventually reach a threshold for MS onset and progression. A new sequencing technology has mapped the transient transcriptome (TT), including intergenic RNAs, and antisense intronic RNAs. Through a rigorous colocalization analysis, here we show that genomic regions coding for the TT were significantly enriched for both MS-associated GWAS variants, and DNA binding sites for molecular transducers mediating putative, non-genetic, etiopathogenetic factors for MS (e.g., vitamin D deficiency, Epstein Barr virus latent infection, B cell dysfunction). These results suggest a model whereby TT-coding regions are hotspots of convergence between genetic ad non-genetic factors of risk/protection for MS (and plausibly for other complex disorders). Our colocalization analysis also provides a freely available data resource at www.mscoloc.com for future research on transcriptional regulation in MS

The peptide transporter 1a of the zebrafish Danio rerio, an emerging model in nutrigenomics and nutrition research: Molecular characterization, functional properties, and expression analysis

Background: Peptide transporter 1 (PepT1, alias Slc15a1) mediates the uptake of dietary di/tripeptides in all vertebrates. However, in teleost fish, more than one PepT1-type transporter might function, due to specific whole genome duplication event(s) that occurred during their evolution leading to a more complex paralogue gene repertoire than in higher vertebrates (tetrapods). Results: Here, we describe a novel di/tripeptide transporter in the zebrafish (Danio rerio), i.e., the zebrafish peptide transporter 1a (PepT1a; also known as Solute carrier family 15 member a1, Slc15a1a), which is a paralogue (78% similarity, 62% identity at the amino acid level) of the previously described zebrafish peptide transporter 1b (PepT1b, alias PepT1; also known as Solute carrier family 15 member 1b, Slc15a1b). Also, we report a basic analysis of the pept1a (slc15a1a) mRNA expression levels in zebrafish adult tissues/organs and embryonic/early larval developmental stages. As assessed by expression in Xenopus laevis oocytes and two-electrode voltage clamp measurements, zebrafish PepT1a, as PepT1b, is electrogenic, Na+-independent, and pH-dependent and functions as a low-affinity system, with K0.5 values for Gly-Gln at − 60 mV of 6.92 mmol/L at pH 7.6 and 0.24 mmol/L at pH 6.5 and at − 120 mV of 3.61 mmol/L at pH 7.6 and 0.45 mmol/L at pH 6.5. Zebrafish pept1a mRNA is highly expressed in the intestine and ovary of the adult fish, while its expression in early development undergoes a complex trend over time, with pept1a mRNA being detected 1 and 2 days post-fertilization (dpf), possibly due to its occurrence in the RNA maternal pool, decreasing at 3 dpf (~ 0.5-fold) and increasing above the 1–2 dpf levels at 4 to 7 dpf, with a peak (~ 7-fold) at 6 dpf. Conclusions: We show that the zebrafish PepT1a-type transporter is functional and co-expressed with pept1b (slc15a1b) in the adult fish intestine. Its expression is also confirmed during the early phases of development when the yolk syncytial layer is present and yolk protein resorption processes are active. While completing the missing information on PepT1-type transporters function in the zebrafish, these results open to future investigations on the similar/differential role(s) of PepT1a/PepT1b in zebrafish and teleost fish physiology.publishedVersio

Metabolic-imaging of human glioblastoma live tumors: A new precision-medicine approach to predict tumor treatment response early

Glioblastoma (GB) is the most severe form of brain cancer, with a 12-15 month median survival. Surgical resection, temozolomide (TMZ) treatment, and radiotherapy remain the primary therapeutic options for GB, and no new therapies have been introduced in recent years. This therapeutic standstill is primarily due to preclinical approaches that do not fully respect the complexity of GB cell biology and fail to test efficiently anti-cancer treatments. Therefore, better treatment screening approaches are needed. In this study, we have developed a novel functional precision medicine approach to test the response to anticancer treatments in organoids derived from the resected tumors of glioblastoma patients