Deconvolution and total least squares in finding the impulseresponse of an electromagnetic system from measured data

Total least squares (TLS) is a method of solving over-determined sets of linear equations AX≈b when there are errors both in the observation vector b(m×1) and in the data matrix A(m×n). This method is particularly useful when the data matrix A is singular or highly ill conditioned. We present the method of finding the TLS by applying the singular value decomposition to the discrete deconvolution problem. Numerical results are presented for finding the impulse response of a transmission line from experimental data. The advantage of this approach is that this method can be automated based on the signal to noise ratio of the measured data     

KINETICS STUDIES OF THE DEVOLATILIZATION OF INDIAN COALS IN ISOTHERMAL AND NONISOTHERMAL CONDITIONS IN THERMOBALANCE AND IN A BATCH REACTOR

Kinetics studies of devolati1ization of Indian coals in inert gas atmosphere have been carried out under isothermal and nonisothermal conditions. Heating rates had negligible effects on the kinetic parameters under nonisothermal conditions. The devolati1ization reaction was found to be of the first order. The overall activation energy was found to be around 30 Kcal/mole. Isothermal data obtained from the batch reactor were also found to fit in the rate expression for a homogeneous first order, reversible reaction within temperature range of 380-445°C. The reaction was found to be kinetically controlled within the coal particles.     

Volume/surface formulation for analyzing scattering from coatedperiodic strips

A surface/surface formulation was used by Perte et al. (see IEEE Trans. Antennas. Propagat.) to analyze the scattering from periodic planar coated strips. This paper is an extension of that work where a combined volume/surface formulation has been used to solve the same problem. This formulation can be applied to problems which involve an inhomogeneous dielectric medium or/and a thick dielectric which requires the inclusion of the edge currents which were neglected as a simplification. Results obtained using the volume/surface formulation have been compared with the results published in the paper written by Petre et al. which were obtained using a surface/surface formulation     

The variation in optical gap of amorphous In33Se33Sb33 thin films with temperatures of heat treatment

Amorphous thin films of the ternary compound In₃₃Se₃₃Sb₃₃ have been produced by a vacuum evaporation technique. The optical gap Eg^opt of In₃₃Se₃₃Sb₃₃ thin films is measured as a function of temperature of heat treatment. It was found that the optical gap has a higher value than that of the binary compound In₅₀Se₅₀ at the initial stages of heat treatment, but after a particular temperature (423 K) of heat treatment, the value of optical gap decreases appreciably in the case of In₃₃Se₃₃Sb₃₃ thin films, while it increased in the case of In₅₀Se₅₀ thin films.     

The modal performance measure for parameter optimization of powersystem stabilizers

This paper develops an optimization approach using the modal performance measure for the selection of power system stabilizer (PSS) parameters in multimachine power systems. The goal of the optimization problem is to damp out the sustained low frequency oscillations in the outputs of a linearized power system. Thus, the modal performance measure optimization problem is to select a set of PSS parameters so that the area under the envelop of the oscillatory output response will be minimum. This paper also considers bounded and unbounded PSS parameters and compares the effects of bounds on the end results. Furthermore, this work also shows that the performance measure is not a convex function in the PSS parameters. That is, there exist many local minima and possibly a global minimum. Single-machine infinite-bus and two-machine three-bus power systems are used to show the effectiveness of the proposed work     

Rapid spread of HIV among injecting drug users in north-eastern states of India

Manipur, a north-eastern state of India bordering Myanmar, has experienced very rapid transmission of the human immunodeficiency virus (HIV) among its vast drug-injecting population. Seroprevalence among intravenous drug users increased from 0 per cent in September 1989 to 50 per cent within six months. With a minimum injecting population of 15,000 and seropositivity of over 50 per cent, the infection quickly spread to the population at large. One per cent of antenatal mothers tested seropositive by 1991. Forming part of the area of South-East Asia known as the Golden Triangle, and producing opium and its derivatives, Myanmar shares a long international border with four States of the region, and populations with a common language and culture move freely across borders. Two other north-eastern states of India bordering Myanmar have faced a similar epidemic within a short period of time. As a result of serosurveillance for HIV since 1986, the epidemic could be detected at an early stage. The present paper provides an account of the results of ongoing comprehensive studies conducted in the north-eastern states of India on drug-related HIV infection, already a serious problem, but possibly still restricted to that region of the country. The prevalence of intravenous drug users, their HIV serological status, the demographic profile, risk behaviour, the spread of the infection to other groups and the problems of harm minimization are also covered.     

Photo-cross-linking of rabbit skeletal troponin I deletion mutants with troponin C and its thiol mutants: the inhibitory region enhances binding of troponin I fragments to troponin C

Contraction of vertebrate striated muscle is regulated by the strong Ca(2+)-dependent interaction between troponin I (TnI) and troponin C (TnC). To critically evaluate this interaction, we generated four recombinant deletion fragments of rabbit fast skeletal TnI: the NH2-terminal fragment (TnI1-94), the NH2 terminus and the inhibitory region (TnI1-120), the inhibitory region and the COOH terminus (TnI96-181), and the COOH-terminal fragment (TnI122-181) containing amino acid residues 1-94, 1-120, 96-181, and 122-181, respectively. Native TnC and seven thiol mutants, containing single cysteine residues in the two globular domains and in the central helix of TnC, e.g., Cys-12, Cys-21, Cys-57, Cys-89, Cys-122, Cys-133, and Cys-158, were labeled with 4-maleimidobenzophenone, and their interaction with the recombinant TnI fragments and the synthetic inhibitory peptide (TnI98-114, residues 98-114) was studied by photo-cross-linking. Extensive cross-linking occurred between various domains of TnC and TnI. The cross-linking patterns (a) showed that both NH2- and COOH-terminal fragments of TnI are accessible to both of the globular domains of TnC, (b) indicated that linkage of the NH2- and COOH-terminal sequences to the inhibitory region of TnI (TnIir) caused marked enhancement of cross-linking with native TnC and all seven thiol mutants, and (c) identified the region in TnC where TnIir binds as that containing residues 98, 133, 158, and 57. Thus, the results suggest that TnI and TnC may adopt flexible and dynamic conformations in which multiple interactions involving various domains of the two polypeptides occur and TnIir acting as a linker facilitates these interactions. The interaction of TnI and its fragments with actin, TnC, and TnT, considered together with the biological activity indicates that residues 96-120 represent a key structural and functional region of TnI. Whereas the NH2-terminal region of TnI stabilizes binding to TnC and TnT, the COOH-terminal region stabilizes TnC and actin binding.     

Molecular characterization and in situ localization of a mouse retinal taurine transporter

Various ocular tissues have a higher concentration of taurine than plasma. This taurine concentration gradient across the cell membrane is maintained by a high-affinity taurine transporter. To understand the physiological role of the taurine transporter in the retina, we cloned a taurine transporter encoding cDNA from a mouse retinal library, determined its biochemical and pharmacological properties, and identified the specific cellular sites expressing the taurine transporter mRNA. The deduced protein sequence of the mouse retinal taurine transporter (mTAUT) revealed >93% sequence identity to the canine kidney, rat brain, mouse brain, and human placental taurine transporters. Our data suggest that the mTAUT and the mouse brain taurine transporter may be variants of one another. The mTAUT synthetic RNA induced Na+- and Cl(-)-dependent [3H]taurine transport activity in Xenopus laevis oocytes that saturated with an average Km of 13.2 microM for taurine. Unlike the previous studies, we determined the rate of taurine uptake as the external concentration of Cl- was varied, a single saturation process with an average apparent equilibrium constant (K(Cl-)) of 17.7 mM. In contrast, the rate of taurine uptake showed a sigmoidal dependence when the external concentration of Na+ was varied (apparent equilibrium constant, K(Na+) approximately 54.8 mM). Analyses of the Na+- and Cl(-)-concentration dependence data suggest that at least two Na+ and one Cl- are required to transport one taurine molecule via the taurine transporter. Varying the pH of the transport buffer also affected the rate of taurine uptake; the rate showed a minimum between pH 6.0 and 6.5 and a maximum between pH 7.5 and 8.0. The taurine transport was inhibited by various inhibitors tested with the following order of potency: hypotaurine > beta-alanine > L-diaminopropionic acid > guanidinoethane sulfonate > beta-guanidinopropionic acid > chloroquine > gamma-aminobutyric acid > 3-amino-1-propanesulfonic acid (homotaurine). Furthermore, the mTAUT activity was not inhibited by the inactive phorbol ester 4alpha-phorbol 12,13-didecanoate but was inhibited significantly by the active phorbol ester phorbol 12-myristate 13-acetate, which was both concentration and time dependent. The cellular sites expressing the taurine transporter mRNA in the mouse eye, as determined by in situ hybridization technique, showed low levels of expression in many of the ocular tissues, specifically the retina and the retinal pigment epithelium. Unexpectedly, the highest expression levels of taurine transporter mRNA were found instead in the ciliary body of the mouse eye.     

Prediction of heat transfer coefficient during condensation of water and R-134a on single horizontal integral-fin tubes

This paper presents a few salient features of an investigation carried out to study the heat transfer augmentation during condensation of water and R-134a vapor on horizontal integral-fin tubes. The experimental investigation was performed on two different experimental set-ups for water and R-134a. The test-sections were manufactured by machining fins over plain copper tubes of 24.4 ± 0.6 mm outside diameter. The performance of two types of finned tubes viz. circular integral-fin tubes (CIFTs) and spine integral-fin tubes (SIFTs) was studied for the condensation of water and R-134a. These tubes were positioned one by one inside the test-condenser to perform the experiments. All together the experiments were conducted for the condensation on 10 different test-section tubes. With the help of the experimental results, authors have developed an empirical equation. This equation predicts the condensing heat transfer coefficient from their own experimental data for the condensation over CIFTs and SIFTs within a range of ± 15% and experimental data of other thirteen investigators in a range of ± 35% for condensation of water and different refrigerants.     

Argyrophilic nucleolar organiser regions (AgNORs) in breast lesions

Nucleolar organiser regions (NORs) demonstrated by argyrophilia of NOR-proteins are indicator of cellular proliferative activity. The NORs can be identified in the nuclei as brown or black dots with silver colloidal staining technique in formalin fixed paraffin sections and in cytology smears. Seventy-five cases including 45 tissue sections and 30 fine needle aspiration cytology (FNAC) smears of benign and malignant lesions of breast have been studied to evaluate the significance and practical application of AgNOR count per nucleus. Out of 45 tissue sections 15 belonged to fibrocystic disease, 10 fibro-adenomas and 20 carcinomas and of the 30 FNAC smears, 10 were fibrocystic disease, 8 fibro-adenomas and 12 carcinomas. In fibrocystic disease the mean AgNOR count was 1.60 (FNAC group-0.75, tissue section-1.61). In fibro-adenomas it was 1.61 (FNAC-1.63, tissue section-1.59). The mean count in carcinoma was 12.10 (FNAC-12.08, tissue section-12.10). The difference in AgNOR count in fibrocystic disease and fibro-adenoma was not significant, but that between benign breast lesion and carcinoma was significant. No difference was observed between FNAC and tissue section groups in benign or malignant lesions. The simple staining technique can be used as an additional criterion to differentiate the benign and malignant lesions of breast.