1,924 research outputs found

    Quantification of Self-Healing Effect of Bacillus Subtilis on Cementitious Material

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    In this paper, the self-healing ability of the bacterial concrete is tested and compared numerically with the conventional concrete. Micro-cracks cause degradation of strength which leads to deterioration of structures. To improve the life span of structures, self-healing techniques are used. One such technique is bacterial concrete which remediates cracks in concrete by using microbes as the self-healing agent. The self-healing agent is embedded into the cement mortar and its behaviour is studied. Control and bacterial specimens are cast and the tests like compressive strength, porosity, UPV test, ESEM, EDAX are done. ESEM and EDAX results show that the calcium precipitates formed in the micro-cracks at micron levels, to initiate the self-healing of mortar. UPV results show 3.90% of healing at the end of 45 days

    Study on the presentations of Chronic Liver Disease in correlation to their etiologies.

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    INTRODUCTION : Chronic Liver Disease (CLD) and its sequelae form a major part of gastroenterological workload in any large hospital. As well known, it is a disease with very high degree of morbidity and mortality. In the past, CLD was broadly divided into alcoholic and post hepatitis varieties. Over the years, with the advent of newer techniques for identification of viruses, biochemical markers, and newer histopathological methods, it is now possible to enlarge the classification and attach more informative labels to such cases. Even among virus related CLD, a large group so far labeled as Non A, Non B, identification of Hepatitis C has become an established practice. Transfusion associated NANB hepatitis has a new perspective now. Despite these transformations, a small proportion of patients fail to demonstrate any known viral marker raising further questions. There are now well documented studies on the beneficial effects of antiviral agents in the management of chronic hepatitis B and C. Hence it becomes almost mandatory to determine if a given case of CLD is virus related or not, so that a decision regarding the use of such antiviral agents can be made. Another problem, which is assuming importance, is co-existence of more than one hepatotropic virus. While the co-infection or superinfection of HBV and Hepatitis D Virus (HDV) is well studied, the significance of the presence of viral makers of HBV and HCV in the same patient is not yet clear. Which agent is responsible for the observed liver damage and how the presence of one virus alters the biological behavior of other, are questions which have already caught the attention of hepatologists worldwide. AIM : To study about the various clinical, biochemical and pathological presentations of chronic liver disease and to estimate their relative frequencies. 1. To estimate the contribution of hepatitis virus B & C in causing chronic liver disease in an urban setup 2. To find out the relative prevalence of NASH in patients diagnosed to have chronic liver disease (CLD) OBJECTIVES : The study was conducted with following specific objectives in mind. 1. What is the relative frequency of clinical, biochemical, pathological abnormalities found in chronic liver disease of various etiologies 2. What is the prevalence rate of HBV and HCV in patients with CLD 3. Should NASH be considered to be an emerging risk for CLD in urban population? PATIENTS & METHODOLOGY : The study was conducted in Government General Hospital, Chennai, during the period September 2003 to August 2004. 100 consecutive adult patients admitted to the male and female wards of Medical Gastroenterology ward diagnosed to have CLD (by criteria given below) were included in the study. CONCLUSIONS : 1. Chronic liver disease is a major health problem in this area. 2. 60 out of 100 patients with CLD were related to Ethanol and HBV either singly or in combination. 3. The incidence of HCV infection is very low in this part of the world (4%). 4. A sizeable proportion (28%) belongs to the group of cryptogenic cirrhosis which calls for a lot of research in this sphere to detect new viruses or environmental factors responsible. 5. The prevalence of NASH in patients with CLD is 3% 6. Obesity, Hypertriglyceredemia and Diabetes were present in patients with NASH either singly or in combination. 7. Coexistence of HBV and Alcoholic liver disease does not alter the histopathology or clinical severity of the illness . 8. In view of the too small number of HCV cases, we could not document the histopathological characteristics claimed to be distinctive of HCV infection

    On the static effective Lindbladian of the squeezed Kerr oscillator

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    We derive the static effective Lindbladian beyond the rotating wave approximation (RWA) for a driven nonlinear oscillator coupled to a bath of harmonic oscillators. The associated dissipative effects may explain orders of magnitude differences between the predictions of the ordinary RWA model and results from recent superconducting circuits experiments on the Kerr-cat qubit. The higher-order dissipators found in our calculations have important consequences for quantum error-correction protocols and parametric processses

    Progressive cavitating leukoencephalopathy: Case report of a rare childhood onset neurodegenerative disease

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    The leukoencephalopathies with cystic changes form a distinct subtype of childhood onset neurodegenerativedisorders. This group has heterogeneous etiological differentials that primarily include mitochondrial disorders, someleukodystrophies and central nervous system infections. We report this case of a 17-month old girl who presented withseizures, episodic encephalopathy, elevated blood lactate level and lactate peak on magnetic resonance spectroscopy,a typical imaging picture noted on cranial magnetic resonance imaging and absence of deletions or duplications ofmitochondrial deoxyribonucleic acid. Progressive cavitating leukoencephalopathy (PCL) is a recently described entitywith only a few cases reported so far. We report the first case of PCL from India. Accurate diagnosis can be made, notonly, by the presence of typical clinicoradiological findings of PCL, but also by the awareness of, and, ruling out of,the various other differential diagnoses that are discussed in detail below

    A cross sectional study of prevalence of depression among patients with cerebrovascular accident

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    Background: Depression is one of the most common neuropsychiatric condition in patients with stroke. Early identification of depression for stroke patients can improve the outcome leading to better quality of life. Prevalence and determinants of post stroke depression are highly variable and there is paucity of data in Indian literature.Methods: This cross-sectional study was conducted at neurology department of Saveetha Medical College, Chennai. All patients with history of stroke within past one month attending neurology department who fulfilled the inclusion criteria were taken up for the study after getting consent. Neurological examination and CT brain findings were noted with the site of lesion. All patients were evaluated for depression using ICD 10 criteria. MADRS score was used to assess the severity of depression. Chi square was used for statistical analysis.Results: The mean age of subjects in the study was 56.54±10.82 years. The prevalence of depression among patients with stroke in our study was 75.8%. Among classifying those with depression based on severity using MADRS score, 35% had mild depression and 65% had moderate depression. There was no severe depression in our sample. There was no statistically significant difference between prevalence of depression based on side of lesion.Conclusions: In this study the prevalence of depression among patients with cerebrovascular accident was found to be 75.8%. From this study we learn that the prevalence of depression in patients with stroke is high and this shows that regular screening of patients with stroke for depression might help in earlier detection and management of depression

    A modelling study of the latitudinal variations in the nighttime plasma temperatures of the equatorial topside ionosphere during northern winter at solar maximum

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    International audienceLatitudinal variations in the nighttime plasma temperatures of the equatorial topside ionosphere during northern winter at solar maximum have been examined by using values modelled by SUPIM (Sheffield University Plasmasphere Ionosphere Model) and observations made by the DMSP F10 satellite at 21.00 LT near 800 km altitude. The modelled values confirm that the crests observed near 15° latitude in the winter hemisphere are due to adiabatic heating and the troughs observed near the magnetic equator are due to adiabatic cooling as plasma is transported along the magnetic field lines from the summer hemisphere to the winter hemisphere. The modelled values also confirm that the interhemispheric plasma transport needed to produce the required adiabatic heating/cooling can be induced by F-region neutral winds. It is shown that the longitudinal variations in the observed troughs and crests arise mainly from the longitudinal variations in the magnetic meridional wind. At longitudes where the magnetic declination angle is positive the eastward geographic zonal wind combines with the northward (summer hemisphere to winter hemisphere) geographic meridional wind to enhance the northward magnetic meridional wind. This leads to deeper troughs and enhanced crests. At longitudes where the magnetic declination angle is negative the eastward geographic zonal wind opposes the northward geographic meridional wind and the trough depth and crest values are reduced. The characteristic features of the troughs and crests depend, in a complicated manner, on the field-aligned flow of plasma, thermal conduction, and inter-gas heat transfer. At the latitudes of the troughs/crests, the low/high plasma temperatures lead to increased/decreased plasma concentrations.Key words: Ionosphere (equatorial ionosphere; ionosphere-atmosphere interactions

    Heptaphyrins: expanded porphyrins with seven heterocyclic rings

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    Expanded porphyrins containing seven pyrrole/heterocyclic rings linked in a cyclic fashion are termed heptaphyrins. The number of π-electrons in heptaphyrins depends on the number ofmeso carbon bridges used to link the heterocyclic rings, accordingly heptaphyrins with 28π-electrons and 30π-electrons are reported to date. Both condensation reactions of the appropriate precursors and acid-catalysed oxidative coupling reactions have been utilized to synthesise the heptaphyrins. The 30π heptaphyrins exhibit rich structural diversity where some of the heterocyclic rings in the macrocycle undergo a 180° ring flipping. An overview of the synthetic methods employed for the synthesis of heptaphyrins, their spectroscopic properties, structural behaviour and aromatic properties are highlighted in this paper

    A diagrammatic method to compute the effective Hamiltonian of driven nonlinear oscillators

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    In this work, we present a new method, based on Feynman-like diagrams, for computing the effective Hamiltonian of driven nonlinear oscillators. The pictorial structure associated with each diagram corresponds directly to a Hamiltonian term, the prefactor of which involves a simple counting of topologically equivalent diagrams. We also leverage the algorithmic simplicity of our scheme in a readily available computer program that generates the effective Hamiltonian to arbitrary order. At the heart of our diagrammatic method is a novel canonical perturbation expansion developed in phase space to capture the quantum nonlinear dynamics. A merit of this expansion is that it reduces to classical harmonic balance in the limit of 0\hbar\rightarrow0. Our method establishes the foundation of the dynamic control of quantum systems with the precision needed for future quantum machines. We demonstrate its value by treating five examples from the field of superconducting circuits. These examples involve an experimental proposal for the Hamiltonian stabilization of a three-legged Schr\"odinger cat, modeling of energy renormalization phenomena in superconducting circuits experiments, a comprehensive characterization of multiphoton resonances in a driven transmon, a proposal for an novel inductively shunted transmon circuit, and a characterization of classical ultra-subharmonic bifurcation in driven oscillators. Lastly, we benchmark the performance of our method by comparing it with experimental data and exact Floquet numerical diagonalization

    Zika Virus-induced Acute Myelitis and Motor Deficits in Adult Interferon αβ/γ Receptor Knockout Mice

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    Zika virus (ZIKV) has received widespread attention because of its effect on the developing fetus. It is becoming apparent, however, that severe neurological sequelae, such as Guillian-Barrë syndrome (GBS), myelitis, encephalitis, and seizures can occur after infection of adults. This study demonstrates that a contemporary strain of ZIKV can widely infect astrocytes and neurons in the brain and spinal cord of adult, interferon α/β receptor knockout mice (AG129 strain) and cause progressive hindlimb paralysis, as well as severe seizure-like activity during the acute phase of disease. The severity of hindlimb motor deficits correlated with increased numbers of ZIKV-infected lumbosacral spinal motor neurons and decreased numbers of spinal motor neurons. Electrophysiological compound muscle action potential (CMAP) amplitudes in response to stimulation of the lumbosacral spinal cord were reduced when obvious motor deficits were present. ZIKV immunoreactivity was high, intense, and obvious in tissue sections of the brain and spinal cord. Infection in the brain and spinal cord was also associated with astrogliosis as well as T cell and neutrophil infiltration. CMAP and histological analysis indicated that peripheral nerve and muscle functions were intact. Consequently, motor deficits in these circumstances appear to be primarily due to myelitis and possibly encephalitis as opposed to a peripheral neuropathy or a GBS-like syndrome. Thus, acute ZIKV infection of adult AG129 mice may be a useful model for ZIKV-induced myelitis, encephalitis, and seizure activity

    Small-Animal Models of Zika Virus

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    Zika virus (ZIKV) infection can result in serious consequences, including severe congenital manifestations, persistent infection in the testes and neurologic sequelae. After a pandemic emergence, the virus has spread to much of the new world and has been introduced to many countries outside of endemic areas as infected travelers return to their home countries. Rodent models have been important in gaining a better understanding of the wide range of disease etiologies associated with ZIKV infection and for the initial phase of developing countermeasures to prevent or treat viral infections. We discuss herein the advantages and disadvantages of small animal models that have been developed to replicate various aspects of disease associated with ZIKV infection
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