2,407 research outputs found
POEMS Syndrome Diagnosed 10âYears after Disabling Peripheral Neuropathy
Peripheral neuropathy is characterized as a generalized, relatively homogeneous process affecting many peripheral nerves and predominantly affecting distal nerves. The epidemiology of peripheral neuropathy is limited since the disease presents with varying etiology, pathology, and severity. Toxic, inflammatory, hereditary, and infectious factors can cause damage to the peripheral nerves resulting in peripheral neuropathy. Peripheral neuropathy is most commonly caused by diabetes, alcohol, HIV infection, and malignancy. We report a case of a 42-year-old female with 10-year history of progressively worsening peripheral neuropathy, hypothyroidism, and skin changes who presents with dyspnea secondary to recurrent pleural and pericardial effusions. Prior to her arrival, her peripheral neuropathy was believed to be secondary to chronic demyelinating inflammatory polyneuropathy (CDIP) given elevated protein in the cerebral spinal fluid (CSF) which was treated with intravenous immunoglobulin (IVIG) and corticosteroids. Unfortunately, her peripheral neuropathy did not have any improvement. Incidentally, patient was found to have splenomegaly and papilledema on physical exam. Serum protein electrophoresis showed a monoclonal pattern of IgA lambda. Patient met the diagnostic criteria for POEMS (polyneuropathy, organomegaly, endocrinopathy, M-protein, and skin changes) syndrome. An underlying diagnosis of POEMS syndrome should be considered in patients with chronic debilitating neuropathy and an elevated protein in the CSF
Efficient and accurate calculation of exact exchange and RPA correlation energies in the Adiabatic-Connection Fluctuation-Dissipation theory
Recently there has been a renewed interest in the calculation of
exact-exchange and RPA correlation energies for realistic systems. These
quantities are main ingredients of the so-called EXX/RPA+ scheme which has been
shown to be a promising alternative approach to the standard LDA/GGA DFT for
weakly bound systems where LDA and GGA perform poorly. In this paper, we
present an efficient approach to compute the RPA correlation energy in the
framework of the Adiabatic-Connection Fluctuation-Dissipation formalism. The
method is based on the calculation of a relatively small number of eigenmodes
of RPA dielectric matrix, efficiently computed by iterative density response
calculations in the framework of Density Functional Perturbation Theory. We
will also discuss a careful treatment of the integrable divergence in the
exact-exchange energy calculation which alleviates the problem of its slow
convergence with respect to Brillouin zone sampling. As an illustration of the
method, we show the results of applications to bulk Si, Be dimer and atomic
systems.Comment: 12 pages, 6 figures. To appear in Phys. Rev.
Modelling of dishing for metal chemical mechanical polishing
In this paper, a physical model for the development of dishing during metal chemical mechanical polishing (CMP) is proposed. The main assumption of the model is that material removal occurs predominantly at the pad/wafer contacts. The distribution of pad/wafer contact size is studied first. This distribution is used as an input for a model of the dependence for the material removal rate on the line width. A relation that describes the development of dishing as a function of overpolish time will be presented. The model describes to a great accuracy the observed dishing effects, using one free paramete
TUNet: A Block-online Bandwidth Extension Model based on Transformers and Self-supervised Pretraining
We introduce a block-online variant of the temporal feature-wise linear
modulation (TFiLM) model to achieve bandwidth extension. The proposed
architecture simplifies the UNet backbone of the TFiLM to reduce inference time
and employs an efficient transformer at the bottleneck to alleviate performance
degradation. We also utilize self-supervised pretraining and data augmentation
to enhance the quality of bandwidth extended signals and reduce the sensitivity
with respect to downsampling methods. Experiment results on the VCTK dataset
show that the proposed method outperforms several recent baselines in both
intrusive and non-intrusive metrics. Pretraining and filter augmentation also
help stabilize and enhance the overall performance.Comment: Published as a conference paper at ICASSP 2022, 5 pages, 4 figures, 3
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Model-based Experimental Design in Electrochemistry
The following thesis applies an experimental design framework to investigate properties
of electron transfer kinetics and homogeneous catalytic reactions. The approach is
model-based and the classical Butler-Volmer description is chosen to describe the
fundamental electrochemical reaction at a conductive interface. The methodology
focuses on two significant design variables: the applied potential at the electrode and
mass transport mode induced by physical arrangement.
An important problem in electrochemistry is the recovery of model parameters from
output current measurements. In this work, the identifiability function is proposed
as a measure of correspondence between the parameters and output variable. Under
diffusion-limit conditions, plain Monte Carlo optimization shows that the function is
globally non-identifiable, or equivalently the correspondence is generally non-unique.
However by selecting linear voltammetry as the applied potential, the primary parameters in the Butler-Volmer description are theoretically recovered from a single set
of data. The result is accomplished via applications of Sobol ranking to reduce the
parameter set and a sensitivity equation to inverse these parameters.
The use of hydrodynamic tools for investigating electron transfer reactions is next
considered. The work initially focuses on the rotating disk and its generalization - the
rocking disk mechanism. A numerical framework is developed to analyze the latter,
most notably the derivation of a Levich-like expression for the limiting current. The
results are then used to compute corresponding identifiability functions for each of
the above configurations. Potential effectiveness of each device in recovering kinetic
parameters are straightforwardly evaluated by comparing the functional values. Furthermore, another hydrodynamic device - the rotating drum, which is highly suitable
for viscous and resistive solvents, is theoretically analyzed. Combined with previous
results, this rotating drum configuration shows promising potential as an alternative
tool to traditional electrode arrangement.
The final chapter illustrates the combination of modulated input signal and appro-
priate mass transport regimes to express electro-catalytic effects. An AC voltammetry
technique plays an important role in this approach and is discussed step-by-step from
simple redox reaction to the complete ECâČ catalytic mechanism. A general algorithm
based on forward and inverse Fourier transform functions for extracting harmonic
currents from the total current is presented. The catalytic effect is evaluated and
compared for three cases: macro, micro electrodes under diffusion control condition
and in micro fluidic environments. Experimental data are also included to support
the simulated design results
How swelling debts give rise to a new type of politics in Vietnam
Vietnam has seen fast-rising debts, both domestic and external, in recent years. This paperreviews the literature on credit market in Vietnam, providing an up-to-date take on the domesticlending and borrowing landscape. The study highlights the strong demand for credit in both therural and urban areas, the ubiquity of informal lenders, the recent popularity of consumer financecompanies, as well as the governmentâs attempts to rein in its swelling public debt. Given thehigh level of borrowing, which is fueled by consumerism and geopolitics, it is inevitable that theamount of debt will soon be higher than the saving of the borrowers. Unlike the conventional wisdom that creditors have more bargaining power over the borrowers, we suggest thatâalbeitlacking a quantitative estimationâwhen the debts pile up so high that the borrowers could not repay, the power dynamics may reverse. In this new politics of debt, the lenders fear to lose the money's worth and continue to lend and feed the insolvent debtors. The result is a toxic lending/borrowing market and profound lessons, from which the developing world could learn
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