45,991 research outputs found
Troponins, Acute Coronary Syndrome and Renal Disease: From Acute Kidney Injury Through End-stage Kidney Disease
The diagnosis of acute coronary syndromes (ACS) is heavily dependent on cardiac biomarker assays, particularly cardiac troponins. ACS, particularly non-ST segment elevation MI, are more common in patients with acute kidney injury, chronic kidney disease (CKD) and end-stage kidney disease (ESKD), are associated with worse outcomes than in patients without kidney disease and are often difficult to diagnose and treat. Hence, early accurate diagnosis of ACS in kidney disease patients is important using easily available tools, such as cardiac troponins. However, the diagnostic reliability of cardiac troponins has been suboptimal in patients with kidney disease due to possible decreased clearance of troponin with acute and chronic kidney impairment and low levels of troponin secretion due to concomitant cardiac muscle injury related to left ventricular hypertrophy, inflammation and fibrosis. This article reviews the metabolism and utility of cardiac biomarkers in patients with acute and chronic kidney diseases. Cardiac troponins are small peptides that accumulate in both acute and chronic kidney diseases due to impaired excretion. Hence, troponin concentrations rise and fall with acute kidney injury and its recovery, limiting their use in the diagnosis of ACS. Troponin concentrations are chronically elevated in CKD and ESKD, are associated with poor prognosis and decrease the sensitivity and specificity for diagnosis of ACS. Yet, the evidence indicates that the use of high-sensitivity troponins can confirm or exclude a diagnosis of ACS in the emergency room in a significant proportion of kidney disease patients; those patients in whom the results are equivocal may need longer in-hospital assessment
Conversion of glassy antiferromagnetic-insulating phase to equilibrium ferromagnetic-metallic phase by devitrification and recrystallization in Al substituted PrCaMnO
We show that PrCaMnO with 2.5% Al substitution and
LaCaMnO (LCMO) exhibit qualitatively similar and
visibly anomalous M-H curves at low temperature. Magnetic field causes a broad
first-order but irreversible antiferromagnetic (AF)-insulating (I) to
ferromagnetic (FM)-metallic (M) transition in both and gives rise to soft FM
state. However, the low temperature equilibrium state of
PrCaMnAlO (PCMAO) is FM-M whereas that
of LCMO is AF-I. In both the systems the respective equilibrium phase coexists
with the other phase with contrasting order, which is not in equilibrium, and
the cooling field can tune the fractions of the coexisting phases. It is shown
earlier that the coexisting FM-M phase behaves like `magnetic glass' in LCMO.
Here we show from specially designed measurement protocols that the AF-I phase
of PCMAO has all the characteristics of magnetic glassy states. It devitrifies
on heating and also recrystallizes to equilibrium FM-M phase after annealing.
This glass-like AF-I phase also shows similar intriguing feature observed in
FM-M magnetic glassy state of LCMO that when the starting coexisting fraction
of glass is larger, successive annealing results in larger fraction of
equilibrium phase. This similarity between two manganite systems with
contrasting magnetic orders of respective glassy and equilibrium phases points
toward a possible universality.Comment: Highlights potential of CHUF (Cooling and Heating in Unequal Fields),
a new measurement protoco
Large-Signal Simulation of 94 GHz Pulsed Silicon DDR IMPATTs Including the Temperature Transient Effect
In this paper large-signal modeling and simulation has been carried to study the frequency chirping due to temperature transients and the large-signal power and efficiency of pulsed silicon Double-Drift Region (DDR) Impact Avalanche Transit Time (IMPATT) device operating at 94 GHz. A large-signal simulation method based on non-sinusoidal voltage excitation incorporating the transient thermal effect has been developed by the authors. Results show that the device is capable of delivering a peak pulsed power output of 17.5 W with 12.8% efficiency when the voltage modulation is 60%. The maximum junction temperature rise is 350.2 K for a peak pulsed bias current of 6.79 A with 100 ns pulsewidth and 0.5 percent duty cycle; whereas the chirp bandwidth is 8.3 GHz
A Study on the structure of proton
The structure function of the proton has been investigated and has been found
to possess the power law behaviour in conformity with the empirical fits to the
experimental findings. We have estimated F(x, Q)/F(x,
Q) with the anomalous dimension D predicted from the
statistical model as an input and the result is found to be in good agreement
with the recent data available in the deep inelastic region.Comment: 3 page
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Life after 100? A Leader’s Guide to Resilient Family Businesses
How many businesses survive more than a 100years? Of the businessesthat do survive,how many remain financially robust? If the lifespan of a company on the Standard and Poor’s (S&P)500 list is an indication of longevity,then evidence shows that ithas shrunk from 33 years in 1964 to 24 years by 2016.By 2027, itis forecast to shrink to just 12 years.1Put differently, at the current survival rate, more than 75%of thecompanies currently quoted on the S&P 500 woulddisappearin the next decade.Family-ownedbusinesses tend to mirror these survival patterns. Alargeproportion of family-ownedbusinesses struggle to survive beyond the second orthird generation.According to the Family Business Institute, only 30% of these organizations last into a second generation. Only 12% remain viable into a third anda miniscule3% continueinto the fourth generation or beyond.What have these 3% businesses and the familybusiness owners done differently that is likely to have contributed to their resilience? What can be learnt about the group that have livedbeyond 100
Global monopole in scalar tensor theory
The well known monopole solution of Barriola and Vilenkin (BV) resulting from
the breaking of a global SO(3) symmetry is extended in general relativity along
with a zero mass scalar field and also in Brans-Dicke(BD) theory of gravity.In
the case of BD theory, the behaviour of spacetime and other variables such as
BD scalar field and the monopole energy density have been studied
numerically.For monopole along with a zero mass scalar field, exact solutions
are obtained and depending upon the choice of arbitary parameters, the
solutions either reduce to the BV case or to a pure scalar field solution as
special cases.It is interesting to note that unlike the BV case the global
monopole in the BD theory does exert gravitational pull on a test particle
moving in its spacetime.Comment: 12 pages LaTex, 3 postscript figures, Communicated to
Class.Quant.Gra
Magnetic glass in Shape Memory Alloy : Ni45Co5Mn38Sn12
The first order martensitic transition in the ferromagnetic shape memory
alloy Ni45Co5Mn38Sn12 is also a magnetic transition and has a large field
induced effect. While cooling in the presence of field this first order
magnetic martensite transition is kinetically arrested. Depending on the
cooling field, a fraction of the arrested ferromagnetic austenite phase
persists down to the lowest temperature as a magnetic glassy state, similar to
the one observed in various intermetallic alloys and in half doped manganites.
A detailed investigation of this first order ferromagnetic austenite (FM-A) to
low magnetization martensite (LM-M) state transition as a function of
temperature and field has been carried out by magnetization measurements.
Extensive cooling and heating in unequal field (CHUF) measurements and a novel
field cooled protocol for isothermal MH measurements (FC-MH) are utilized to
investigate the glass like arrested states and show a reverse martensite
transition. Finally, we determine a field -temperature (HT) phase diagram of
Ni45Co5Mn38Sn12 from various magnetization measurements which brings out the
regions where thermodynamic and metastable states co-exist in the HT space
clearly depicting this system as a 'Magnetic Glass'.Comment: Magnetic field tunes kinetic arrest and CHUF shows devitrification
and melting of Magnetic glas
Spherical collapse with heat flow and without horizon
We present a class of solutions for a heat conducting fluid sphere, which
radiates energy during collapse without the appearance of horizon at the
boundary at any stage of the collapse. A simple model shows that there is no
accumulation of energy due to collapse since it radiates out at the same rate
as it is being generated.Comment: RevTeX, 3 page
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