106 research outputs found
Automatic Bridge-based Interface for Differential Capacitive Full Sensing
Abstract The authors here propose, for the first time, an automatic analog interface for differential capacitance estimation, able to reveal and quantify both low and high (full-range) capacitive variations. The working principle is based on a modified De-Sauty AC bridge configuration where two differential capacitances and two resistances are employed, one of which is implemented by a Voltage Controlled Resistor (VCR). Through a suitable feedback loop, a very accurate estimation over the complete range of the differential capacitance variation is possible, while the bridge allows a continuous differential capacitance evaluation without the need of knowing the accurate value of the sensor baseline and/or its variation range. A general but very simple formula, considering both the "autobalancing" and the "out-of-equilibrium" ranges, is also given. Theoretical, experimental and simulated results are in a very good agreement. Sensitivity and resolution values, typical of sensors and their interfaces, have been determined in a practical case, showing satisfactory values
reliable and inexpensive solar irradiance measurement system design
Abstract In this work, we present an innovative low cost sensor and algorithm for the monitoring and measurement of solar irradiance. This parameter is usually estimated using pyranometers, often based on thermopile. They are quite expensive, also because need additional hardware for data acquisition and manipulation as well as non-negligible installation costs. The system architecture and novel algorithm here proposed employ small PhotoVoltaic (PV) cells and a digital sensor interface. Moreover, the logic section permits to tilt the sensor allowing to track the sun with improved accuracy
MMP-9 immunohistochemical expression is correlated with histologic grade in feline diffuse iris melanoma
Feline diffuse iris melanoma (FDIM) is the most common primary intraocular neoplasm in cats (Dubielzig, 2017). It is usually a malignant tumor, even if slowly progressive, thus representing an unique spontaneous model of the aggressive, although rare, human iris melanoma (Demirci et al., 2002). In cats, the extent of the tumor within the eye, expressed as histological grade, is considered a good predictor of survival (Kalishman et al., 1998). In the context of the neoplastic cells-tumor microenvironment interaction, Matrix Metalloproteinase-9 (MMP-9) is an endopeptidase able to digest the extracellular matrix with involvement in tumor invasion (Nagase et al., 2006). MMP-9 expression has been positively correlated with metastasizing behavior in human posterior uveal melanoma (El-Shabrawi et al., 2001).
The present study investigates the expression of MMP-9 in a caseload of formalin-fixed paraffin-embedded FDIMs in relation to the histological grade (Kalishman et al., 1998) and mitotic index (MI) (threshold=7/10 hpf) (Wiggans et al., 2016). Sixty-one samples of FDIM evaluated on light microscopy (Figure 1) were selected (grade I n=22, grade II n=20, grade III n=19). Immunohistochemical staining with standard ABC method was performed using a mouse anti-MMP-9 antibody (Porcellato et al., 2014). Results were semi-quantitatively scored and compared by Mann-Whitney U test.
MMP-9 was expressed in 59,1% grade I FDIM, 90,0% grade II and 80,0% grade III. Tumors with MMP-9 expression in more than 50% of neoplastic cells were 13,6% in grade I cases, 40,0% in grade II and 36,8% in grade III. MMP-9 was expressed in 71,4% of FDIM with MI 647 and 92,3% of FDIM with MI>7. MMP-9 expression differed significantly between grade I and the other two grades, and between groups with low and high MI. In conclusion, intense expression of MMP-9 seems to correlate with the histological aggressiveness of FDIM
Suppression of estrus in cats with melatonin implants
The objective of this study was to assess the efficacy of a subcutaneous melatonin implant to suppress estrus in queens (felis catus). The hypothesis was that this implant would temporarily and reversibly suppress estrus in queens without producing any clinically detectable side effects. Fourteen adult queens were maintained in cages under artificial illumination (14 h light:10 h dark) for 45 d and then randomly assigned to one of two treatments. At interestrus, queens received a single subcutaneous melatonin implant (18 mg; Melovine [CEVA Sante Animal, Libourne, France]; MEL: n = 9), or a single subcutaneous placebo implant without melatonin (0 mg; PLA; n = 5). At the next estrus, all queens received a second MEL (n = 9) or PLA (n = 5) implant. Blood samples were taken when queens displayed estrous signs and during interestrus to measure estradiol (E2) and progesterone (P4), respectively, by radioimmunoassay. There were no significant differences in duration of the interestrus interval in PLA cats, regardless of whether the implants were placed during interestrus or estrus (6.0 ± 9.7 d vs. 6.0 ± 9.7 d, respectively; least square means [LSM] ± SEM). However, when MEL implants were placed during interestrus, the duration of interestrus was approximately twice as long as that occurring when MEL implants were placed during estrus (113.3 ± 6.1 d vs. 61.1 ± 6.8 d, respectively; P < 0.01). Serum E2 and P4 concentrations were similar in queens with PLA and MEL implants and in queens that received implants in estrus and interestrus. In conclusion, a subcutaneous MEL implant effectively and reversibly suppressed estrus in queens for approximately 2 to 4 mo with no clinically detectable side effects.Facultad de Ciencias Veterinaria
Avoiding, diagnosing and treating well leg compartment syndrome after pelvic surgery
Background
Patients undergoing prolonged pelvic surgery may develop compartment syndrome of one or both lower limbs in the absence of direct trauma or preâexisting vascular disease (well leg compartment syndrome). This condition may have devastating consequences for postoperative recovery, including loss of life or limb, and irreversible disability.
Methods
These guidelines represent the collaboration of a multidisciplinary group of colorectal, vascular and orthopaedic surgeons, acting on behalf of their specialty associations in the UK and Ireland. A systematic analysis of the available peerâreviewed literature was undertaken to provide an evidence base from which these guidelines were developed.
Results
These guidelines encompass the risk factors (both patientâ and procedureârelated), diagnosis and management of the condition. Key recommendations for the adoption of perioperative strategies to facilitate prevention and effective treatment of well leg compartment syndrome are presented.
Conclusion
All surgeons who carry out abdominopelvic surgical procedures should be aware of well leg compartment syndrome, and instigate policies within their own institution to reduce the risk of this potentially lifeâchanging complication
Directionality of nuclear recoils in a liquid argon time projection chamber
The direct search for dark matter in the form of weakly interacting massive
particles (WIMP) is performed by detecting nuclear recoils (NR) produced in a
target material from the WIMP elastic scattering. A promising experimental
strategy for direct dark matter search employs argon dual-phase time projection
chambers (TPC). One of the advantages of the TPC is the capability to detect
both the scintillation and charge signals produced by NRs. Furthermore, the
existence of a drift electric field in the TPC breaks the rotational symmetry:
the angle between the drift field and the momentum of the recoiling nucleus can
potentially affect the charge recombination probability in liquid argon and
then the relative balance between the two signal channels. This fact could make
the detector sensitive to the directionality of the WIMP-induced signal,
enabling unmistakable annual and daily modulation signatures for future
searches aiming for discovery. The Recoil Directionality (ReD) experiment was
designed to probe for such directional sensitivity. The TPC of ReD was
irradiated with neutrons at the INFN Laboratori Nazionali del Sud, and data
were taken with 72 keV NRs of known recoil directions. The direction-dependent
liquid argon charge recombination model by Cataudella et al. was adopted and a
likelihood statistical analysis was performed, which gave no indications of
significant dependence of the detector response to the recoil direction. The
aspect ratio R of the initial ionization cloud is estimated to be 1.037 +/-
0.027 and the upper limit is R < 1.072 with 90% confidence levelComment: 20 pages, 10 figures, submitted to Eur. Phys. J.
Study on cosmogenic activation above ground for the DarkSide-20k project
The activation of materials due to the exposure to cosmic rays may become an
important background source for experiments investigating rare event phenomena.
DarkSide-20k is a direct detection experiment for galactic dark matter
particles, using a two-phase liquid argon time projection chamber filled with
49.7 tonnes (active mass) of Underground Argon (UAr) depleted in 39Ar. Here,
the cosmogenic activity of relevant long-lived radioisotopes induced in the
argon and other massive components of the set-up has been estimated; production
of 120 t of radiopure UAr is foreseen. The expected exposure above ground and
production rates, either measured or calculated, have been considered. From the
simulated counting rates in the detector due to cosmogenic isotopes, it is
concluded that activation in copper and stainless steel is not problematic.
Activation of titanium, considered in early designs but not used in the final
design, is discussed. The activity of 39Ar induced during extraction,
purification and transport on surface, in baseline conditions, is evaluated to
be 2.8% of the activity measured in UAr from the same source, and thus
considered acceptable. Other products in the UAr such as 37Ar and 3H are shown
to not be relevant due to short half-life and assumed purification methods
Measurement of isotopic separation of argon with the prototype of the cryogenic distillation plant Aria for dark matter searches
The Aria cryogenic distillation plant, located in Sardinia, Italy, is a key component of the DarkSide-20k experimental program for WIMP dark matter searches at the INFN Laboratori Nazionali del Gran Sasso, Italy. Aria is designed to purify the argon, extracted from underground wells in Colorado, USA, and used as the DarkSide-20k target material, to detector-grade quality. In this paper, we report the first measurement of argon isotopic separation by distillation with the 26 m tall Aria prototype. We discuss the measurement of the operating parameters of the column and the observation of the simultaneous separation of the three stable argon isotopes: 36Ar , 38Ar , and 40Ar . We also provide a detailed comparison of the experimental results with commercial process simulation software. This measurement of isotopic separation of argon is a significant achievement for the project, building on the success of the initial demonstration of isotopic separation of nitrogen using the same equipment in 2019
RF and microwave reconfigurable bandpass filter design using optimized active inductor circuit
Current-Mode Wheatstone Bridge
Current chapter deals with Wheatstone Bridges with the focus on Current-Mode Wheatstone Bridge and its associated signal conditioning circuits. The operation, advantages and drawbacks of each circuit are discussed in detail. To make the comparison between traditional Voltage-Mode Wheatstone Bridge and Current-Mode Wheatstone Bridge more convenient, at the beginning of this chapter, the concept of Voltage-Mode Wheatstone Bridge is briefly summarized. The theory of Mixed-Mode Wheatstone Bridge and read-out circuits are also included. © 2019, Springer Nature Switzerland AG
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