333 research outputs found

    Structure model index does not measure rods and plates in trabecular bone

    Get PDF
    Structure model index (SMI) is widely used to measure rods and plates in trabecular bone. It exploits the change in surface curvature that occurs as a structure varies from spherical (SMI = 4), to cylindrical (SMI = 3) to planar (SMI = 0). The most important assumption underlying SMI is that the entire bone surface is convex and that the curvature differential is positive at all points on the surface. The intricate connections within the trabecular continuum suggest that a high proportion of the surface could be concave, violating the assumption of convexity and producing regions of negative differential. We implemented SMI in the BoneJ plugin and included the ability to measure the amounts of surface that increased or decreased in area after surface mesh dilation, and the ability to visualize concave and convex regions. We measured SMI and its positive (SMI+) and negative (SMI-) components, bone volume fraction (BV/TV), the fraction of the surface that is concave (CF), and mean ellipsoid factor (EF) in trabecular bone using 38 X-ray microtomography (XMT) images from a rat ovariectomy model of sex steroid rescue of bone loss, and 169 XMT images from a broad selection of 87 species' femora (mammals, birds, and a crocodile). We simulated bone resorption by eroding an image of elephant trabeculae and recording SMI and BV/TV at each erosion step. Up to 70%, and rarely less than 20%, of the trabecular surface is concave (CF 0.155 – 0.700). SMI is unavoidably influenced by aberrations from SMI-, which is strongly correlated with BV/TV and CF. The plate-to-rod transition in bone loss is an erroneous observation resulting from SMI's close and artefactual relationship with BV/TV. SMI cannot discern between the distinctive trabecular geometries typical of mammalian and avian bone, whereas EF clearly detects birds' more plate-like trabeculae. EF is free from confounding relationships with BV/TV and CF. SMI results reported in the literature should be treated with suspicion. We propose that EF should be used instead of SMI for measurements of rods and plates in trabecular bone

    Epilepsy and suicide: a narrative review

    Get PDF
    The epilepsy represents a challenge for life expectancy and quality of life either for social and relational consequences due to stigma and for the consequences of the disorder itself. Suicidal behaviors are more frequent in the persons with epilepsy than in the general population. In addition to those shared with other chronic diseases, the condition of a person with epilepsy recognizes particular risk factors related to the clinical characteristics, demographic, socioeconomic and relational conditions. The frequent comorbidity with psychiatric disorders, first of all depression, complicates the clinical picture both because of neurobiological underpinnings underlying the two disorders and the negative interaction on the quality of life. The hopelessness is strongly correlated to suicidal ideation and its evaluation can be considered a relevant and reliable tool for measuring suicidal ideation. A careful evaluation of suicidal ideation, taking into account demographic and psychological conditions of patients, as well as clinical, social, economic situations, is warranted. The diagnosis and treatment of the disease has to take into account a bio-psycho-social approach that allows the integration of medical, psychological and social aspects

    A Case Report of Ruxolitinib Induced Hypocalcemia: A Stochastic or Deterministic Effect?

    Get PDF
    Ruxolitinib is a novel selective JAK 1/2 inhibitor approved for the treatment of myelofibrosis (MF) and polycythemia vera (PCV). Hypocalcemia associated with ruxolitinib has not been reported in early trials or in literature. A 65 year female with history of CKD stage 3, PCV since 1989, papillary thyroid carcinoma, total thyroidectomy and hypoparathyroidism since 1996 presented with complaints of severe myalgia, fatigue, paresthesia and critical hypocalcemia. Her corrected S. Ca 5.8 mg /dl (8.9-10.1 mg/dL) and Ionised Ca 2.9 mg/dl (4.5 - 5.4 mg/dL). Other labs showed stable creatinine 1.5 mg/dL, intact PTH 29 pg/ml(14-72pg/ml) and 25,OH vitamin D level 35ng/ml (30-100ng/ml). She was recently started on ruxolitinib 4 months ago for PCV due to worsening thrombocytosis. Since the start of ruxolitinib she had these symptoms. Follow up labs showed rapid fall in blood counts because of which ruxolitinib was stopped after 2 months. She continued to have symptoms even after stopping the drug. Her symptoms were attributed to very low S. Ca level. She was treated with multiple IV / oral calcium doses and initiated on calcitriol once her phosphorus dropped below 5.5mg/dl. The Ca level corrected and was discharged on Ca carbonate, Ca acetate and calcitriol

    PV Cell Characteristic Extraction to Verify Power Transfer Efficiency in Indoor Harvesting System

    Get PDF
    A method is proposed to verify the efficiency of low-power harvesting systems based on Photovoltaic (PV) cells for indoor applications and a Fractional Open-Circuit Voltage (FOCV) technique to track the Maximum Power Point (MPP). It relies on an algorithm to reconstruct the PV cell Power versus Voltage (P-V) characteristic measuring the open circuit voltage and the voltage/current operating point but not the short-circuit current as required by state-of-the-art algorithms. This way the characteristic is reconstructed starting from the two values corresponding to standard operation modes of dc-dc converters implementing the FOCV Maximum Power Point Tracking (MPPT) technique. The method is applied to a prototype system: an external board is connected between the transducer and the dc-dc converter to measure the open circuit voltage and the voltage/current operating values. Experimental comparisons between the reconstructed and the measured P-V characteristics validate the reconstruction algorithm. Experimental results show the method is able to clearly identify the error between the transducer operating point and the one corresponding to the maximum power transfer, whilst also suggesting corrective action on the programmable factor of the FOCV technique. The proposed technique therefore provides a possible way of estimating MPPT efficiency without sampling the full P-V characteristic

    The role of measurement and simulation in additive manufacturing within the frame of Industry 4.0

    Get PDF
    In recent years, manufacturing industry has been facing a new and powerful technology, able to produce complex and cost efficient parts, the additive manufacturing (AM). The rapid development and expansion of the use of this method was accompanied by a vast development of equipment and software in mainly two directions, namely the optimization of a designed part with respect to its weight and mechanical performance and the simulation of the fabrication of this part via AM. Nevertheless, several drawbacks on the fabrication of components of a variety of materials have been observed, especially with reference to the final product dimensions and the corresponding distortions caused by a number of factors that influence the final result. In the present work, the correlation between the measurements of specific characteristics of components fabricated via AM and the data provided by the simulation models are presented. Also, the role of these measurements on the development of a component consistent with the initial design is underlined. To this end, a test case is presented, in which a part of high geometrical complexity is realized using the Selective Laser Melting (SLM) method. The comparison between the measurements of the final product reveals the need of constant and consistent measurements for assuring the part's accurate fabrication

    Characterization and genome sequencing of a Citrobacter freundii phage CfP1 harboring a lysin active against multidrug-resistant isolates

    Get PDF
    Citrobacter spp., although frequently ignored, is emerging as an important nosocomial bacterium able to cause various superficial and systemic life-threatening infections. Considered to be hard-to-treat bacterium due to its pattern of high antibiotic resistance, it is important to develop effective measures for early and efficient therapy. In this study, the first myovirus (vB_CfrM_CfP1) lytic for Citrobacter freundii was microbiologically and genomically characterized. Its morphology, activity spectrum, burst size, and biophysical stability spectrum were determined. CfP1 specifically infects C. freundii, has broad host range (>85 %; 21 strains tested), a burst size of 45 PFU/cell, and is very stable under different temperatures (20 to 50 °C) and pH (3 to 11) values. CfP1 demonstrated to be highly virulent against multidrug-resistant clinical isolates up to 12 antibiotics, including penicillins, cephalosporins, carbapenems, and fluroquinoles. Genomically, CfP1 has a dsDNA molecule with 180,219 bp with average GC content of 43.1 % and codes for 273 CDSs. The genome architecture is organized into function-specific gene clusters typical for tailed phages, sharing 46 to 94 % nucleotide identity to other Citrobacter phages. The lysin gene encoding a predicted D-Ala-D-Ala carboxypeptidase was also cloned and expressed in Escherichia coli and its activity evaluated in terms of pH, ionic strength, and temperature. The lysine optimum activity was reached at 20 mM HEPES, pH 7 at 37 °C, and was able to significantly reduce all C. freundii (>2 logs) as well as Citrobacter koseri (>4 logs) strains tested. Interestingly, the antimicrobial activity of this enzyme was performed without the need of pretreatment with outer membrane-destabilizing agents. These results indicate that CfP1 lysin is a good candidate to control problematic Citrobacter infections, for which current antibiotics are no longer effective.This study was funded by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit, COMPETE 2020 (POCI-01-0145-FEDER006684), and the PhD grants SFRH/BPD/111653/2015 and SFRH/BPD/69356/2010

    A gated oscillator clock and data recovery circuit for nanowatt wake-up and data receivers

    Get PDF
    This article presents a data-startable baseband logic featuring a gated oscillator clock and data recovery (GO-CDR) circuit for nanowatt wake-up and data receivers (WuRxs). At each data transition, the phase misalignment between the data coming from the analog front-end (AFE) and the clock is cleared by the GO-CDR circuit, thus allowing the reception of long data streams. Any free-running frequency mismatch between the GO and the bitrate does not limit the number of receivable bits, but only the maximum number of equal consecutive bits (Nm). To overcome this limitation, the proposed system includes a frequency calibration circuit, which reduces the frequency mismatch to ±0.5%, thus enabling the WuRx to be used with different encoding techniques up to Nm = 100. A full WuRx prototype, including an always-on clockless AFE operating in subthreshold, was fabricated with STMicroelectronics 90 nm BCD technology. The WuRx is supplied with 0.6 V, and the power consumption, excluding the calibration circuit, is 12.8 nW during the rest state and 17 nW at a 1 kbps data rate. With a 1 kbps On-Off Keying (OOK) modulated input and −35 dBm of input RF power after the input matching network (IMN), a 10^(−3) missed detection rate with a 0 bit error tolerance is measured, transmitting 63 bit packets with the Nm ranging from 1 to 63. The total sensitivity, including the estimated IMN gain at 100 MHz and 433 MHz, is −59.8 dBm and −52.3 dBm, respectively. In comparison with an ideal CDR, the degradation of the sensitivity due to the GO-CDR is 1.25 dBm. False alarm rate measurements lasting 24 h revealed zero overall false wake-ups

    An evolutionarily young defense metabolite influences the root growth of plants via the ancient TOR signaling pathway.

    Get PDF
    To optimize fitness a plant should monitor its metabolism to appropriately control growth and defense. Primary metabolism can be measured by the universally conserved TOR (Target of Rapamycin) pathway to balance growth and development with the available energy and nutrients. Recent work suggests that plants may measure defense metabolites to potentially provide a strategy ensuring fast reallocation of resources to coordinate plant growth and defense. There is little understanding of mechanisms enabling defense metabolite signaling. To identify mechanisms of defense metabolite signaling, we used glucosinolates, an important class of plant defense metabolites. We report novel signaling properties specific to one distinct glucosinolate, 3-hydroxypropylglucosinolate across plants and fungi. This defense metabolite, or derived compounds, reversibly inhibits root growth and development. 3-hydroxypropylglucosinolate signaling functions via genes in the ancient TOR pathway. If this event is not unique, this raises the possibility that other evolutionarily new plant metabolites may link to ancient signaling pathways
    corecore