Modified Threshold-based Spectrum Sensing Approach for VANETs

The Primary User (PU) signal detection in Cognitive Radio (CR) is crucial and is achieved through spectrum sensing techniques. The Energy Detection method is a commonly used technique, and selecting a proper threshold is essential to enhance the efficiency of the CR system. This research paper demonstrates the maximum achievable throughput and validates a Modified Threshold (MT) approach. The authors consider a scenario with multiple antennas at the receiver, where these antennas are correlated and subjected to mobility effects, and they employ the Energy Detection (ED) for spectrum sensing. The study analyzes the system's performance over a Nakagami-m fading channel, considering available correlations among the antenna elements. To compute important statistical values, the Moment Generating Function (MGF) method is employed. The research employs specialized mathematical functions, such as the Lauricella and confluent hypergeometric functions, to derive closed-form expressions for the Probability of Detection when employing the diversity technique. The results indicate a significant enhancement in the performance of the proposed algorithm when utilizing the modified threshold parameter across a wide range of Signal to Noise Ratio (SNR) values. Additionally, increasing the number of branches in the antenna system further improves detection performance. Interestingly, under high fading parameter conditions (m=4), the detection probability is found to be superior with exponential correlation among the L antenna elements compared to other available correlated branches

The design and evaluation of the P₀.₁ method of assessing ventilatory drive

Hypercapnia and/or hypoxia normally cause hyperventilation, The sensitivity to hypercapnia and hypoxia and the resultant hyperventilation is reduced in a patient suffering from damped respiratory centre activity. The P 0.1 method is a modification of the rebreathing technique where a patient rebreathes from a bag prefilled with a mixture of gases of known concentrations. This modification is not sensitive to airflow obstruction as is the case with the ventilatory response of the rebreathing technique. The P 0.1 method has been described by several authors during the past 8 years. There is however the need to standardise the technique. This thesis is an attempt to meet this need. The P 0.1 method involves the occlusion of the inspiratory airway for a set time after the onset of inspiration of a particular breathing cycle. The pressure (P 0.1) at this time, generated by the isometric contraction of the respiratory muscles, is recorded together with the end tidal P C02 . The valve is occluded approximately 20 times during a rebreathing trial lasting for 4 minutes. The plot of P 0.1 versus P C02 is linear and its slope gives an indication of respiratory centre activity. A low slope indicates damped respiratory centre activity. The control electronics was designed using digital logic. The occlusion valve is closed passively during the expiratory phase and then actively held for a preselected time, most frequently for 1OOms, after the onset of inspiration, during the next breathing cycle. The active occlusion period is preselectable between 50ms and 300ms. The inspiratory pressure is recorded at this time, or 10 or 20ms prior to the opening of the valve, by a sample and hold circuit. The occlusion valve can be triggered manually via a push button switch on the front panel, or periodically for preselectable periods every 5 to 30 seconds or pseudo-randomly. Ventilatory phase, pressure preset and autotrigger mode indicators are included as operator aids. In a limited number of clinical trials the equipment worked satisfactorily. During a hypercapnic study the CO2 concentration in the bag progressively increases with a resultant increase in ventilation. The hypercapnic trials carried out yielded encouraging results. The method is simple, rapid and easily reproducible. The regression line plots obtained are linear with correlation coefficients better than those presented in the literature. The sensitivity of the ventilatory drive defined as the slope of the P 0.1 versus P C02 regression line for a group of 10 healthy adult males tested was 0.79 ± 0.47 cmH 2 o/mmHg. The device is in clinical use in the Respiratory Clinic at Groote Schuur Hospital. Further work needs to be done to investigate the full meaning of the results obtained and to what extent it can be used as a noninvasive diagnostic and screening technique for respiratory disorders. The P 0.1 method will help the clinician to assess non-invasively the degree of impairment of respiratory centre output in patients suspected of having a damped respiratory centre and who may also suffer pulmonary mechanical defects because the technique is independent of airflow

Stabilization of bacterial cells culture on immobilized Alginate beads and optimization of Congo red decolorization

544-552The paper deals with the primary objective to optimize different parameters such as concentration, temperature, pH, time and size of cells for the decolorization of azo dye (Congo red) by using bacterial isolates by the method of immobilized bacterial cells. Staphylococcus aureus immobilized beads show a maximum dye decolorization of 94% under optimum condition and found to be more efficient in dye decolorization. The optimum value for degradation is found to be 35°C, for 400 mg/L of concentration of dye at the medium pH of 7. The order of the reaction was found to be first order with the rate constant of 0.073 h-1. The dye adsorbed on the bead surface follows Freundlich adsorption isotherm with the constant values are K = 1.368 and 1/n = 0.773. Studies have been carried out by FTIR, GC-MS analysis for confirming the biodegradation of Congo Red by the immobilized bacterial cells. The results reported warrant further investigation to establish the usefulness of these isolates for bioremediation and biodegradation application such as wastewater treatment

OPTIMIZATION OF PROCESS PARAMETERS USING RESPONSE SURFACE METHODOLOGY FOR REMOVAL OF PHENOL BY NANO ZERO VALENT IRON IMPREGNATED CASHEW NUT SHELL

Objective: The present research is an attempt to optimize the process parameters for phenol removal from aqueous solution using Nano zero-valent iron (NZVI) impregnated cashew nut shell (NZVI-CNS) by adopting statistical tool Response Surface Methodology-Box Behnken Design (RSM-BB).Methods: Box Behnken Design (RSM-BB) design was used to explore the effect of variables on the removal of phenol. In RSM-BB method, high and low values were assigned for the five variables viz. initial pH, NZVI-CNS dosage, initial concentration, contact time and temperature. The preparation was carried out by simple liquid-phase reduction method, namely borohydride reduction method.Results: The results of RSM-BB method showed the significant effect of pH (A), Dose (B), initial concentration (C), time (D), and temperature (E) on phenol removal from aqueous solution. The results of ANOVA and regression of the second order model showed that the linear effects of Dose (B) and Temperature and cross products effects of temperature and pH were more significant. All the critical variables having the greatest effect on the removal of phenol from Nano zero valent iron impregnated cashew nut shell.Conclusion: Nano zero valent iron impregnated cashew nut shell successfully employed to remove phenol from aqueous solution. The factors optimized in the present work would helpful in phenol removal from aqueous solution.Â

Stabilization of bacterial cells culture on immobilized Alginate beads and optimization of Congo red decolorization

The paper deals with the primary objective to optimize different parameters such as concentration, temperature, pH, time and size of cells for the decolorization of azo dye (Congo red) by using bacterial isolates by the method of immobilized bacterial cells. Staphylococcus aureus immobilized beads show a maximum dye decolorization of 94% under optimum condition and found to be more efficient in dye decolorization. The optimum value for degradation is found to be 35°C, for 400 mg/L of concentration of dye at the medium pH of 7. The order of the reaction was found to be first order with the rate constant of 0.073 h-1. The dye adsorbed on the bead surface follows Freundlich adsorption isotherm with the constant values are K = 1.368 and 1/n = 0.773. Studies have been carried out by FTIR, GC-MS analysis for confirming the biodegradation of Congo Red by the immobilized bacterial cells. The results reported warrant further investigation to establish the usefulness of these isolates for bioremediation and biodegradation application such as wastewater treatment

Developing methods to prevent or treat microbial colonisation of titanium dental implant surfaces

Titanium (Ti) dental implants are a successful treatment modality to replace missing teeth. Success is traditionally defined as the retention of the Ti dental implant but fails to account for peri-implant inflammatory diseases such as peri-implant mucositis and peri-implantitis. Peri-implant diseases are caused by the formation of pathogenic bacteria biofilms on the implant surface and disease progression can lead to dysfunctional and unaesthetic outcomes. There is no universally accepted treatment or management protocol for peri-implant disease. The objectives were to develop methods to prevent bacterial adhesion to Ti implant surfaces or treat existing biofilms. The relationship between bacterial adhesion of common early coloniser bacteria and topological features on dental implant surfaces was studied. Reproducible model systems were identified to be used in studies of biofilm formation and disruption. Early bacterial adhesion was investigated on engineered Ti surfaces created using Scanning-Laser-Melting or on Ti nanotubule surfaces. Photoactivation of Ti oxide films was investigated on thermally or anodically oxidised Ti and demonstrated the potential to pre-treat implant surfaces to reduce bacterial attachment. Finally chemical disinfection of Ti surfaces with a novel Eucalyptus Oil (EO) based formulation was demonstrated to increase the permeation of bactericidal agents into immature biofilms formed on Ti surfaces

Burden and Determinants of Malignancy in Solitary Nodule of Thyroid in a Tertiary Care Hospital in Chennai

BACKGROUND: The concern with thyroid nodules is the possibility of malignancy. Thyroid cancers are rare, accounting for only 1.0% of all cancers in most populations and 0.5% of all cancer deaths. Nonetheless, thyroid cancers occur in approximately 5% of all thyroid nodules independent of their size. With thyroid nodules being so prevalent in the general population, it is important to have a clear strategy of assessing nodules and determining which of these will require surgery or can be managed conservatively. The main problem posed by the discovery of a thyroid nodule is distinguishing between a benign and a malignant lesion. Nowadays, this problem has largely been solved by fine-needle biopsy. When performed by an experienced cytologist, this technique allows diagnosis of the nature of thyroid nodules with great sensitivity and specificity. . But FNAC is, however not without limitations; accuracy is lower in suspicious cytology and in follicular neoplasms. Despite all the newer techniques available, histopatholgy remains the most conclusive in the evaluation of the pathology of solitary nodule of thyroid. OBJECTIVES: To evaluate a patient with solitary nodule thyroid in terms of: 1. Clinical presentation, age & sex distribution of solitary nodule thyroid & complications. 2. To compare and correlate the findings of investigation i.e. FNAC,USG with the histopathology of resected specimen. 3. Usefulness of FNAC,USG,HPE in the management of solitary nodule thyroid. 4. Differential Diagnosis for solitary nodule thyroid. MATERIALS AND METHODS: This is a prospective study going to be conducted in the department of General surgery, GOVERNMENT STANLEY MEDICAL COLLEGE FROM (MAY 2018 TO MAY 2019) SOURCE OF DATA: The patients admitted in our hospital wards for management of SOLITARY NODULE OF THYROID from May 2018 to May 2019 will be taken up for the study. Study design : Descriptive study. Sample size : Total number of eligible patients admitted during study period(May 2018 to May 2019). Sample design : Purposive sampling. Study place : Dept. of General Surgery,STANLEY MEDICAL COLLEGE. Study period : May 2018 to May 2019. METHOD OF COLLECTION OF DATA: ▪ Pre tested Questionnaire will be filled based on history given. ▪ Clinical examination of patient. ▪ Thyroid profile. ▪ Routine investigations. ▪ Ultrasound of the neck. ▪ Fine needle aspiration cytology with hypodermic needle of 21-24 gauge. ▪ Indirect laryngoscopy will be done to rule out a symptomatic paralysis of vocal cords & also for medico legal purpose. ▪ Surgery as per the diagnosis made. ▪ Histopathology of resected specimen. ▪ Age,sex distribution, Symptomatology. ▪ Indication for surgery and its complications will be analysed. INCLUSION CRITERIA: 1. All the eligible patients admitted to STANLEY MEDICAL COLLEGE during the period of study will be included. 2. All the patients of age more than 13years. 3. Both sex are included. EXCLUSION CRITERIA 1. On evaluation more than one thyroid nodule within the gland are excluded. 2. Pregnant and Lactating women. 3. Patients unfit for surgery. RESULT: Commonest presentation of solitary thyroid nodule was asymptomatic. The Peak incidence of solitary nodule was observed in 3rd to 5th decade, constituting 58% of the cases studied. Females predominated in number over males in occurrence of solitary nodule in ratio of 1:15.67. The common causes of solitary nodule was MNG (16%), follicular adenoma (14%), adenomatous goiter(56%). 96% of cases presented in euthyroid state. Incidence of malignancy in solitary thyroid nodule was 12%. Male to female ratio in case of malignant nodule was1:6. Incidence of carcinoma in females presenting as solitary nodule was higher compared to that of males. The most common cause of malignancy was papillary carcinoma (83.33%) followed by follicular carcinoma (16.67%). INTERPRETATION AND CONCLUSION: Solitary nodule of thyroid is more common in females.Solitary nodule of thyroid is more common in the age group of 20-50years.Most of the patients with solitary nodule of thyroid present with swelling alone.Most of the patients with solitary nodule of thyroid are in euthyroid state.Incidence of malignancy in female patients presenting with solitary nodule thyroid is more.commonest cause of solitary nodule of thyroid is adenoma. USG can be used to detect multi-nodular goitre in patients presenting with solitary nodule thyroid. FNAC is the investigation of choice in the evaluation of solitary nodule of thyroid. It has few pitfalls. In such situations, only histopathology can confirm the exact pathology. It detects papillary carcinoma in a solitary nodule with high sensitivity and specificity. Papillary carcinoma is the most common malignancy of thyroid, followed by follicular carcinoma

EVALUATION OF PHYTASE PRODUCTION BY HYPOCREA LIXII SURT01 IN SUBMERGED AND SOLID-STATE FERMENTATIONS

Objective: Phytases have important applications in human and animal nutrition because they hydrolyze the phytate present in legumes, cereal grains and oil seeds to release inorganic phosphate. Supplementation of phosphate to the poultry causes a serious problem of eutrophication. This can be reduced by incorporating phytase in poultry feed. Present study explains extracellular phytase production by SmF and SSF from a fungal strain Hypocrea lixii SURT01. Methods: Extracellular phytase production by Hypocrea lixii SURT01 was evaluated in media containing various refined carbon sources (Fructose, Sucrose, Maltose and lactose in concentration ranging from 1.5% to 7.5%) along with standard medium under submerged fermentation (SmF). At the same time, phytase production was studied under Solid State Fermentation (SSF) with four different substrate such as barley, green gram, bengal gram and black gram. Results: In SmF out of different carbon sources in various concentrations, 6% sucrose showed maximum enzyme production (245U/ml). In SSF, barley showed highest phytase yield (1638 Units/ml) on 5th day of incubation. Conclusion: Evaluation of Solid state fermentation showed enhanced phytase production when compared to Submerged Fermentation