Fourier-transform-infrared-spectroscopy based metabolomic spectral biomarker selection towards optimal diagnostic differentiation of diabetes with and without retinopathy

Abstract

The purpose of this study is to identify Fourier transform infrared (FTIR) spectroscopy-based serum metabolomic spectral biomarkers using chemometrics for the diagnosis of Diabetic Retinopathy. FTIR spectroscopy was performed on 85 human serum samples [30 type 2 diabetes patients each without retinopathy and with retinopathy along with 25 normal healthy individuals as control]. Difference between mean spectra (DBMS), forward feature selection (FFS), and Mann–Whitney’s U tests were applied for spectral biomarker selection. Classification of disease conditions was achieved using analysis of different combinations of spectral features with linear, quadratic, and cubic Support Vector Machine at 10-fold cross validation. Twelve spectral signatures extracted by FFS could differentiate diabetes and diabetic retinopathy with 90% sensitivity, 92.7% specificity, and 90.5% overall accuracy. Two peaks (1042, 1114.18?cm^?1) were associated with carbohydrate and polysaccharide content and five peaks (1114.18, 1165, 1211.18, 1402.70, 1451.14, 1657?cm^?1) represented aberrations in total lipid content. Four peaks (1114.18, 1117, 1147, 1165?cm^?1) were associated with protein phosphorylation and three peaks (1527, 1544.71, 1591.10?cm^?1) with Amide II group. Again, lipidic signatures were strongly corroborated with glycosylated hemoglobin levels in diabetic retinopathy and diabetic subjects. Spectral signatures also revealed an elevated level of β-sheet containing proteins in serum in diabetic retinopathy condition. The method was validated through spectral biomarker selection by the DBMS technique. Thus, this method has the capability of diagnostic cost minimization for detection of diabetic retinopathy by label-free spectral biomarker identification.     

Validity of the generalized second law of thermodynamics of the universe bounded by the event horizon in holographic dark energy model

In this paper, we investigate the validity of the generalized second law of thermodynamics of the universe bounded by the event horizon in the holographic dark energy (DE) model. The universe is chosen to be homogeneous and isotropic and the validity of the first law has been assumed here. The matter in the universe is taken in the form of non-interacting two fluid system: one component is the holographic DE model and the other component is in the form of dust.     

Generalized Second Law of Thermodynamics on the Event Horizon for Interacting Dark Energy

Here we are trying to find the conditions for the validity of the generalized second law of thermodynamics (GSLT) assuming the first law of thermodynamics on the event horizon in both cases when the FRW universe is filled with interacting two fluid system- one in the form of cold dark matter and the other is either holographic dark energy or new age graphic dark energy.     

A more powerful test identifying the change in mean of functional data

An existence of change point in a sequence of temporally ordered functional data demands more attention in its statistical analysis to make a better use of it. Introducing a dynamic estimator of covariance kernel, we propose a new methodology for testing an existence of change in the mean of temporally ordered functional data. Though a similar estimator is used for the covariance in finite dimension, we introduce it for the independent and weakly dependent functional data in this context for the first time. From this viewpoint, the proposed estimator of covariance kernel is more natural one when the sequence of functional data may possess a change point. We prove that the proposed test statistics are asymptotically pivotal under the null hypothesis and consistent under the alternative. It is shown that our testing procedures outperform the existing ones in terms of power and provide satisfactory results when applied to real data.     

Theoretical and experimental investigation of the fast- andslow-scale instabilities of a DC-DC converter

We use an exact formulation based on nonlinear maps to investigate both the fast-scale and slow-scale instabilities of a voltage-mode buck converter operating in the continuous conduction mode and its interaction with a filter. Comparing the results of the exact model with those of the averaged model shows the shortcomings of the latter in predicting fast-scale instabilities. We show the impact of parasitics on the onset of chaos using a high-frequency model. The experimentally validated theoretical results of this paper provide an improved understanding of the dynamics of the converter beyond the linear regime and this may lead to less conservative control design and newer applications     

An efficient design of embedded memories and their testability analysis using Markov chains

This article presents a design strategy for efficient and comprehensive random testing of embedded random-access memory (RAM) where neither are the address, read/write and data input lines directly controllable nor are the data output lines externally observable. Unlike the conventional approaches, which frequently employ on-chip circuits such as linear feedback shift register (LFSR), data registers and multibit comparator for verifying the response of the memory-under-test (MUT) with the reference signature of a fault-free gold unit, the proposed technique uses an efficient testable design, which helps accelerate test algorithms by a factor of 0.5n, if the RAM is organized into an n×1 array and improve the test reliability by eliminating the LFSR that is known to have aliasing problems. Another serious problem in embedded memory testing by random test patterns is the problem of memory initialization, which has been tackled here by adding word-line flag registers. The paper has made indepth empirical studies of the functional faults such as stuck-at, coupling, and pattern-sensitive by suitably representing these faults by Markov chains and by simulating these chains to derive various test lengths required for detecting these faults. The simulation results conclusively show that, in order to test a IM-bit RAM for detecting the common functional faults, the proposed technique needs only one second as opposed to about an hour needed by the conventional random testing where memory cells are tested sequentially.An abridged version of this article was published in the IEEE International Conference on Wafer-Scale Integration, January 1989. This research was partially supported by the NSF under grant number MIP-9013092 and by ONR under grant number 85-K-0716.     

Modeling of Gate Current and Capacitance in Nanoscale-MOS Structures

By applying a fully self-consistent solution of the Schrodinger-Poisson equations, a simple unified approach has been developed in order to study the gate current and gate capacitance of nanoscale-MOS structures with ultrathin dielectric layer. In this paper, the model has been employed to investigate various gate structure and material combinations, thereby demonstrating wide applicability of the present model in the design of nanoscale-MOSFET devices. The results obtained by applying the proposed model are in good agreement with experimental data and previous models in the literature. A new result concerning optimum nitrogen content in HfSiON high-k gate-dielectric structure reported in this paper requires experimental verification through device fabrication     

Continuous and discrete variable-structure controls for parallel three-phase boost rectifier

We describe three nonlinear control schemes for a parallel three-phase boost rectifier consisting of two modules. The basic idea, however, can be extended to a system with N modules. All of the control schemes are developed in a synchronous frame. Moreover, each of the closed-loop power-converter modules operates asynchronously without any communication with the other module. Based on the dynamical equations of the parallel converter, we find that independent control of both of the modules on the DQ axes is not necessary and possible. Consequently, we develop control schemes that stabilize the dq axes and limit the zero-axis disturbance by preventing the flow of the pure zero-sequence current. One of the control schemes is developed purely in the discrete domain. It combines the space-vector modulation scheme with a variable-structure control, thereby keeping the switching frequency constant and achieving satisfactory dynamic performance. The performances of the other control schemes are also satisfactory.     

9(R)‐[6(R)‐Hydroxy­methyl‐1‐oxa‐4‐thia­cyclo­hexan‐2‐yl]hypoxanthine–water (4/3), a nucleoside analogue

The title compound, 9(R)‐[6(R)‐hydroxy­methyl‐1‐oxa‐4‐thia­cyclo­hexan‐2‐yl]‐1,9‐di­hydro‐6H‐purin‐6‐one–water (4/3), C₁₀H₁₂N₄O₃S·0.75H₂O, crystallizes in the triclinic space group P1 with four mol­ecules in the asymmetric unit and 0.75 waters of hydration per mol­ecule. The structure was refined to an R value of 0.072 for 3382 observed reflections. The four crystallographically independent mol­ecules are designated A, B, C and D. All four oxa­thia­ne rings adopt the chair conformation and the purine bases are in an anti orientation with respect to the sugar moieties. Molecules A and D and mol­ecules C and B are base paired by a single hydrogen bond of the type N—H?N. These base pairs are again hydrogen bonded to their translated pairs in the direction of a cell diagonal.