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Homology modeling and ligand interaction of Cytochrome b protein
Rohith Kumar Anugolu,Shravan Kumar Gunda,Rajiv Varman Kakarla
Journal of Medical and Allied Sciences , 2011,
Abstract: Cytochrome b is a component of respiratory chain complex III, also known as the bc1 complex or ubiquinol-cytochrome c reductase. These complexes are involved in electron transport and the generation of ATP and thus play a vital role in the cell. The cytochrome bc1 complex is a membrane-bound enzyme that catalyses the transfer of electrons from ubiquinol to cytochrome c, coupling this process to the translocation of protons across the inner mitochondrial membrane. The function of proteins is generally determined by its three-dimensional (3D) structure. Thus, it would be useful to know the 3D structure of the thousands of protein sequences that are emerging from many genome projects. Structural studies on bio-molecules have changed our perception of the biological world in the last twenty years. A number of efforts have been made on structure prediction. One such technique that has found a wide appreciation is Homology modeling which aims at predicting the 3D structure of biomolecules, relying heavily on resources such as pattern/function and sequence. However, the three-dimensional structure of cytochrome b subunit protein (Accession number C4PKA1) from Homo sapiens remains unknown. In the present study, effort was made to generate the three-dimensional (3D) structure of the cytochrome b based on available template (1BGY) structural homologues from Protein Data Bank and the model validated with standard parameters (Procheck). With the predicted model, the ligand was subjected to docking study using FlexX docking tool. Flexible docking was carried out with the HEM - Protoporphyrin X [Heme] as ligand; which was found to bind at His267, Ile268 and Val343 residues on given generated protein. We therefore concluded that the above mentioned residues were the key residue sites for ligand binding. The predicted model showed better results than the template structure with 0% disallowed regions. This study will be used in broad screening of the protein in the respiratory process and can be further implemented in future drug designing.
A Stability Indicating UPLC Method for Candesartan in Bulk Drug Samples  [PDF]
Gunda Srinivas, Kakumani Kishore Kumar, Gangaram V. Kanumula, M. Vishnu Priya, K. Mukkanti
American Journal of Analytical Chemistry (AJAC) , 2012, DOI: 10.4236/ajac.2012.310093
Abstract: A simple, sensitive gradient rapid resolution liquid chromatographic assay method has been developed for the quantitative determination of Candesartan Cilexetil in bulk active pharmaceutical ingredient, used for the treatment of hypertension. The developed method is also applicable for the process related impurities determination. Efficient chromatographic separation was achieved on a C18 stationary phase with simple mobile phase combination delivered in a gradient mode and quantification was by ultraviolet detection at 210 nm at a flow rate of 0.4 mL × min﹣1. In the developed UPLC method the resolution between Candesartan Cilexetil and its two potential impurities was found to be greater than 2.0. Regression analysis showed an r value (correlation coefficient) greater than 0.99 for Candesartan Cilexetil and its two impurities. This method was capable to detect two impurities of Candesartan Cilexetil at a level of 0.003% with respect to test concentration of 1.0 mg × mL﹣1 for a 2 μL injection volume. The bulk active pharmaceutical ingredient was subjected to stress conditions of hydrolysis, oxidation, photolysis and thermal degradation. Considerable degradation was found to occur in oxidative stress conditions. The stress samples were assayed against a qualified reference standard and the mass balance was found close to 99.5%. The developed RP-LC method was validated with respect to linearity, accuracy, precision and robustness.
TRANSMISSION LINE FAULT ANALYSIS USING WAVELET THEORY
Ravindra Malkar,Vaibhav Magdum,Sunil Kumar Gunda
International Journal of Engineering Science and Technology , 2012,
Abstract: This paper describes a Wavelet transform technique to analyze power system disturbance such as transmission line faults with Biorthogonal and Haar wavelets. In this work, wavelet transform based approach,which is used to detect transmission line faults, is proposed. The coefficient of discrete approximation of the dyadic wavelet transform with different wavelets are used to be an index for transmission line fault detection and faulted – phase selection and select which wavelet is suitable for this application. MATLAB/Simulation is used to generate fault signals. Simulation results reveal that the performance of the proposed fault detection indicator is promising and easy to implement for computer relaying application.
In-Stent Ulceration: An Unusual Pathology
Jagadeesh Kumar Kalavakunta,Shravan Gangula,Vishal Gupta
Case Reports in Cardiology , 2014, DOI: 10.1155/2014/893143
Abstract: In-stent restenosis occurs in 10–60% of cases undergoing interventional therapy. Many mechanisms explain the reason for in-stent restenosis, but restenosis due to an ulcerated plaque is very rare and has not been well reported in the literature. We report an interesting case of 72-year-old man presenting with neurological symptoms secondary to in-stent restenosis of the carotid artery caused by an ulcerated plaque. We also explain the different mechanisms for restenosis along with the treatment options. 1. Introduction Interventional therapy has been highly impacted by the number of lesions treated with stents, which exceeds 50% of all interventional procedures. Although stents have been successful in reducing the restenosis compared to balloon angioplasty, in-stent restenosis (ISR) occurs in 10–60% of cases [1–4]. ISR can be explained by many mechanisms, but restenosis due to an ulcerated plaque is very rare and has not been reported in the literature. We report a case where a patient presented with neurological symptoms secondary to an ulcerated ISR of the carotid artery. 2. Case Report A 72-year-old Caucasian man with past medical history of diabetes mellitus, hypertension, smoking, bilateral carotid endarterectomy, and a left carotid artery stent (14 months ago) presented with symptoms of blurred vision and dizziness. He experienced very similar symptoms prior to the past carotid endarterectomy. A subsequent carotid ultrasound showed a 60–79% stenosis of his left internal carotid artery and no significant stenosis of the right internal carotid artery. Carotid angiography showed an eccentric stenosis in the left internal carotid artery at the stent site with a crater/ulcer within the restenosis tissue inside the stent (Figure 1(a)). An Accunet 6.5 filter (Abbott Vascular, Santa Clara, CA) was deployed distal to the stent in the left internal carotid artery. Later, an Acculink (Abbott Vascular) ?mm self-expanding stent was deployed successfully. Postdeployment angiograms revealed brisk flow with no evidence of embolization into the filter, but the ulcerative nature of the crater continued to be present. Balloon dilatation was performed in the mid-portion of the stent after which residual stenosis was approximately 10% with minimal visualization of the crater-like lesion (Figure 1(b)). After successfully retrieving the filter device, final angiograms of cervical and cerebral arteries revealed brisk flow with no evidence of distal embolization maintaining patency of the middle cerebral and anterior cerebral circulation. At the 3-, 6-, 12-, and 24-month
Spectrally Efficient Multi-Carrier Modulation Using Gabor Transform  [PDF]
Shravan Sriram, Naveenkumar Vijayakumar, P. Aditya Kumar, Akash S. Shetty, V. P. Prasshanth, K. A. Narayanankutty
Wireless Engineering and Technology (WET) , 2013, DOI: 10.4236/wet.2013.42017
Abstract:

Non Orthogonal Frequency Division Multiplexing (NOFDM) systems make use of a transmission signal set which is not restricted to orthonormal bases unlike previous OFDM systems. The usage of non-orthogonal bases generally results in a trade-off between Bit Error Rate (BER) and receiver complexity. This paper studies the use of Gabor based on designing a Spectrally Efficient Multi-Carrier Modulation Scheme. Using Gabor Transform with a specific Gaussian envelope; we derive the expected BER-SNR performance. The spectral usage of such a NOFDM system when affected by a channel that imparts Additive White Gaussian Noise (AWGN) is estimated. We compare the obtained results with an OFDM system and observe that with comparable BER performance, this system gives a better spectral usage. The effect of window length on spectral usage is also analyzed.

Management of recurrent cancer of the uterine cervix
Aditi Bhatt,Shravan Kumar Chinnikatti,B. S. Ajaikumar
Oncology Reviews , 2011, DOI: 10.4081/24
Abstract: In developing countries, cervical cancer is the most common cause of cancer deaths in women, due in large part to lack of screening and patient education. Screening results in earlier diagnosis and intervention, but local recurrences still happen and are difficult to treat. Early-stage (IB and IIA) cervical cancer can be cured on an average rate of 80% with either radical surgery or definitive radiation; on the other hand, 30–50% of patients with stage IIB to IV will ultimately fail. The prognosis of recurrent cervical carcinoma is grim regardless of the mode of primary treatment except those with isolated small vaginal or cervical relapse for which a 5-year survival of 35–50% has been reported. These patients constitute less than 10% of all patients with recurrent cervical cancer. In the remaining patients, 5-year survival rates are between 3.2 and 13%. The treatment of this condition has a high morbidity and risk versus benefit of the treatment offered has to be weighed. Refinement in surgical techniques, addition of intraoperative radiation therapy and regional chemotherapy, has improved the outcomes in these patients. There is a lack of randomized trials in this field and the treatment is chosen according to the extent of disease, patients’ general condition and expectation and availability of surgical expertise and treatment facilities.
On Performance of Weighted Fusion Based Spectrum Sensing in Fading Channels
Srinivas Nallagonda,Shravan Kumar Bandari,Sanjay Dhar Roy,Sumit Kundu
Journal of Computational Engineering , 2013, DOI: 10.1155/2013/270612
Abstract: Cognitive radio (CR) is a promising technology for efficient utilization of underutilized spectrum since it is able to detect the occupancy of primary users (PUs) in the different parts of the spectrum. As the sensing channel uncertainties limit the reliability of the spectrum sensing decision, cooperation among multiple CR users is often used to improve the spectrum sensing decision. In this paper, the performance of single CR user based spectrum sensing and cooperative CR user based spectrum sensing (CSS) has been assessed in several channels such as AWGN, log-normal, Hoyt (or Nakagami-q), Rayleigh, Rician (or Nakagami-n), Nakagami-m, and Weibull channels. The performance of two spectrum sensing schemes based on assigning weights to CR users such as (a) weighting according to sensing channel preference and (b) weighting according to the value of decision statistic is evaluated. The performance comparison between two weighting schemes under several fading channels has been made. The performance of proposed CSS has been illustrated through complementary receiver operating characteristics (CROC) for different fading channels. The effects of weighting factors (k and Rf) on overall missed detection performance are shown. The performance of CSS with OR-logic fusion as a special case is also presented for comparison purpose. 1. Introduction Cognitive radio (CR) techniques have been proposed to overcome spectrum scarcity by exploiting underutilized spectrum [1]. It allows the CR users to share the spectrum with primary users (PUs) by opportunistic access. Cognitive radio is defined as a wireless radio device that can adapt to its operating environment through sensing in order to facilitate efficient communications. The CR user can use the spectrum only when it does not create any disturbance or interference to PUs. Thus sensing of vacant spectrum is very important for successful operation of cognitive radio network. Due to the severe multipath fading, a CR may fail to notice the presence of the PU. Therefore, spectrum sensing is an important aspect of CR technology since it needs to sense the PUs accurately and quickly [2, 3]. Spectrum sensing is a hard task because of shadowing, fading, and time-varying nature of wireless channels [4]. The performance of single CR user based spectrum sensing has been studied in several channels such as additive white Gaussian noise (AWGN), log-normal shadowing, Rayleigh, Nakagami- , and Weibull in [5] where the Nakagami- and Weibull distribution provide flexibility in describing the fading severity of the channel and
High Risk Of Immune Reconstitution Inflammatory Syndrome Development Among People Living With HIV/AIDs In Far-Western Region Of Nepal
Shravan Kumar Mishra,R Sharma,T Mahat,BP Gupta
SAARC Journal of Tuberculosis, Lung Diseases and HIV/AIDS , 2013, DOI: 10.3126/saarctb.v10i2.9711
Abstract: I ntroduction : Absolute CD4+ cell counts and CD4/CD8 ratio continue to be an important marker for clinical management of human immunodefi ciency virus (HIV) infection and diagnosis of AIDS. CD4/ CD8 ratio has been also used for prediction of immune reconstitution infl ammatory syndrome (IRIS). The objective of the study was to determine the immunological status in HIV infected people taking anti retroviral therapy (ART) on the basis of CD4+ level and to assess the risk of development of (IRIS) on the basis of CD4+ /CD8+ ratio. Methodology: The study was carried out at Antiretroviral Therapy Centre of Seti Zonal Hospital (SZH), Dhangadi in Western region of Nepal; the second biggest ART center. The study included 760 HIV infected heterosexual, migrant laborer to India from Nepal and their spouses and children. CD profi le was enumerated by FACS Count System. Results: Out of 760, 33(5%) had normal (between1-4) CD4/CD8 ratio, 727 (95%) had abnormal ratio (less than1) of CD4/CD8. The chance of getting IRIS after ART treatment initiation in HIV infected people was 47% among which 30% found to be in high risk of getting IRIS (having CD+/CD8+ ratio less than 0.15) and 17% had chance of immune reconstitution inflammatory syndrome (IRIS) in future course of treatment (having CD+/CD8+ ratio between 0.15-0.30). Conclusion: The study provides the first baseline data on CD4, CD8, and CD4+/CD8+ ratio in HIV infected people in far-western region of Nepal and will sensitize the clinician about the risk of developing IRIS during ART treatment. Furthermore no test is currently available to establish a IRIS diagnosis. Standardized disease-specific clinical criteria for common infectious manifestations of the disease should be developed. SAARC Journal of Tuberculosis, Lung Diseases & HIV/AIDS; 2013; X(2); 35-40 DOI: http://dx.doi.org/10.3126/saarctb.v10i2.9711
Effect of pomegranate juice pre-treatment on the transport of carbamazepine across rat intestine
D Adukondalu,Y Shravan Kumar,Y Vamshi Vishnu,R Shiva Kumar
DARU : Journal of Pharmaceutical Sciences , 2010,
Abstract: "n "nBackground and the purpose of the study: Many drug substances along with a variety of naturally occurring dietary or herbal components interact with the CYP enzyme system.The present study was aimed to investigate the effect of pomegranate juice pre-treatment on the transport of carbamazepine across the rat intestine "nMethods: The transport of carbamazepine across different parts of rat intestine was studied by everted and non-everted sac methods. The control and pomegranate juice (10 ml Kg-1 for 7 days) pre-treated rats were sacrificed and isolated the intestine. The sacs of intestine were prepared, treated with carbamazepine solution and then placed in dulbeccos buffer. Samples were collected periodically and the drug content was estimated using HPLC. Results and conclusion: The results show that there was a significant (p<0.05) difference in the transport of carbamazepine from the intestinal sacs of pretreated with pomegranate juice and control. It seems that pomegranatejuice might have induced CYP3A4enzymes and hence drug is extensively metabolized.
Odontogenic Fibromyxoma of Maxilla: A Rare Case Report
G. Siva Prasad Reddy,B. Surya Kumar,Radhika Muppa,Shravan Kumar Regonda
Case Reports in Dentistry , 2013, DOI: 10.1155/2013/345479
Abstract:
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