Low Complexity Multiplier-less Modified FRM Filter Bank using MPGBP Algorithm

The design of a low complexity multiplier-less narrow transition band filter bank for the channelizer of multi-standard software-defined radio (SDR) is investigated in this paper. To accomplish this, the modal filter and complementary filter in the upper and lower branches of the conventional Frequency Response Masking (FRM) architecture are replaced with two power-complementary and linear phase filter banks. Secondly, a new masking strategy is proposed to fully exploit the potential of the numerous spectra replicas produced by the interpolation of the modal filter, which was previously ignored in the existing FRM design. In this scheme, the two masking filters are appropriately modulated and alternately masked over the spectra replicas from 0 to 2$\pi$, to generate even and odd channels. This Alternate Masking Scheme (AMS) increases the potency of the Modified FRM (ModFRM) architecture for the design of a computationally efficient narrow transition band uniform filter bank (termed as ModFRM-FB). Finally, by combining the adjoining ModFRM-FB channels, Non-Uniform ModFRM-FB (NUModFRM-FB) for extracting different communication standards in the SDR channelizer is created. To reduce the total power consumption of the architecture, the coefficients of the proposed system are made multiplier-less using the Matching Pursuits Generalized Bit-Planes (MPGBP) algorithm. In this method, filter coefficients are successively approximated using a dictionary of vectors to give a sum-of-power-of-two (SOPOT) representation. In comparison to all other general optimization techniques, such as genetic algorithms, the suggested design method stands out for its ease of implementation, requiring no sophisticated optimization or exhaustive search schemes. Another notable feature of the suggested approach is that, in comparison to existing methods, the design time for approximation has been greatly reduced. To further bring down the complexity, adders are reused in recurrent SOPOT terms using the Common Sub-expression Elimination (CSE) technique without compromising the filter performance

Low Complexity Multiplier-less Modified FRM Filter Bank using MPGBP Algorithm

The design of a low complexity multiplier-less narrow transition band filter bank for the channelizer of multi-standard software-defined radio (SDR) is investigated in this paper. To accomplish this, the modal filter and complementary filter in the upper and lower branches of the conventional Frequency Response Masking (FRM) architecture are replaced with two power-complementary and linear phase filter banks. Secondly, a new masking strategy is proposed to fully exploit the potential of the numerous spectra replicas produced by the interpolation of the modal filter, which was previously ignored in the existing FRM design. In this scheme, the two masking filters are appropriately modulated and alternately masked over the spectra replicas from 0 to 2$\pi$, to generate even and odd channels. This Alternate Masking Scheme (AMS) increases the potency of the Modified FRM (ModFRM) architecture for the design of a computationally efficient narrow transition band uniform filter bank (termed as ModFRM-FB). Finally, by combining the adjoining ModFRM-FB channels, Non-Uniform ModFRM-FB (NUModFRM-FB) for extracting different communication standards in the SDR channelizer is created. To reduce the total power consumption of the architecture, the coefficients of the proposed system are made multiplier-less using the Matching Pursuits Generalized Bit-Planes (MPGBP) algorithm. In this method, filter coefficients are successively approximated using a dictionary of vectors to give a sum-of-power-of-two (SOPOT) representation. In comparison to all other general optimization techniques, such as genetic algorithms, the suggested design method stands out for its ease of implementation, requiring no sophisticated optimization or exhaustive search schemes. Another notable feature of the suggested approach is that, in comparison to existing methods, the design time for approximation has been greatly reduced. To further bring down the complexity, adders are reused in recurrent SOPOT terms using the Common Sub-expression Elimination (CSE) technique without compromising the filter performance

Our experience with gastrointestinal stromal tumors over a period of three years from a tertiary care centre

Background: Gastrointestinal stromal tumors (GIST) are the most common mesenchymal neoplasms of the gastrointestinal tract (GIT). Stomach being the commonest site in the GIT, it can occur in the extra-intestinal areas like mesentery, retroperitoneum, omentum and prostate. Exceptionally rare in urinary bladder. Commonly present as solid tumors but cystic degeneration can occur in large tumors especially in extra intestinal regions and may be mistaken for ovarian tumors. We have studied GISTs for a period of 3 years and presenting certain rare entities we encountered. Aim of the study was to study the age and sex prevalence and relative distribution of GISTs in gastrointestinal and extra gastrointestinal (EGIST) areas in various sites, and morphological features in relation to certain rare variants.Methods: 18 surgical resected specimens of gastrointestinal and extra gastrointestinal masses received at the department of pathology, Andhra Medical College, Visakhapatnam, were studied for a period of 3 years from July 2013 to June 2016.Results: GISTs were found to be common in male patients with male to female ratio of 2:1. GISTs of Small bowel showed female predilection. 40% of EGISTs were of larger size and malignant.Conclusions: Age, sex and morphological features were consistent with literature.  Small intestine showed slightly increased prevalence when compared to stomach and large intestine. Tumor size and mitotic count were predictors of outcome. EGISTs showed higher incidence in women and pelvic GISTs have to be carefully evaluated to differentiate them from ovarian tumors

Internal herniation of bowel through the mesodiverticular band in adults - rare presentation - managed by laparoscopy: report of a case

Meckel’s diverticulam is the most common congenital anomaly of gastrointestinal tract. Reporting a case of small bowel obstruction due to internal herniation though the mesodiverticular band, which is a very rare presentation in adults- managed by laparoscopic division of mesodiverticular band. A 35 year old patient, presented to the emergency department with intestinal obstruction. Investigations are suggestive of small bowel obstruction. Diagnostic laparoscopy was done. A meckel’s diverticulum with herniation of small bowel through the mesodiverticular band is found. The mesodiverticular band is divided. As the meckel’s diverticulam was wide mouthed directiculectomy was not done. It can be managed safely by laparoscopy and with less incidence of complications. Morbidity is minimal and rapid return of intestinal function can be achieved

PREPARATION AND EVALUATION OF QUETIAPINE FUMARATE MICROEMULSIONS: A NOVEL DELIVERY SYSTEM

Objective: In the present study, the main objective is to improve solubility and bioavailability of Quetiapine fumarate by formulation into micro emulsion. Method: The Quetiapine fumarate micro emulsion was formulated by using mixture of Isopropyl myristate and oleic acid as oil phase, Tween-80 as surfactant, Isopropyl alcohol and Ethanol mixture as co-surfactant by phase titration method. The prepared formulations were evaluated for Limpidity (% transmittance), droplet size, Zeta potential, Electrical conductivity, Rheology, pH, percentage of drug (assay), emulsifying time, in vitro drug diffusion studies and ex vivo permeation studies. Results and conclusion: The Optimized micro emulsion (Micro emulsion 11) formulation containing Quetiapine fumarate (25mg), Surfactant mixture (50%w/w), Oil (12%w/w) and distilled water (38%w/w) has a droplet size of 26.70 nm with a zeta potential of -5.62 millivolts. The micro emulsion was characterized and compared with the pure drug suspension. Microemulsion showed 31.25 fold increased solubility than that of pure drug suspension. In vitro drug release and ex vivo permeation study results were comparable and correlative. The Microemulsion 11 formulation showed 1.4763 times more drug release than that of pure drug suspension. The formulation was found to be stable for three months. Keywords: Microemulsion, Phase titration method, Quetiapine Fumarate,  Emulsifying time

Dynamics of auto- and heterotrophic picoplankton and associated viruses in Lake Geneva

Microbial dynamics have rarely been investigated in Lake Geneva, known as the largest lake in western Europe. From a 5-month survey, we report dynamic patterns of free-living virus, bacteria and small phytoplankton abundances in response to a variety of environmental parameters. For the first time, we fractionated the primary production to separate the contribution of different size-related biological compartments and measured both bacterial and viral production in addition to experiments conducted to quantify the virus-induced bacterial mortality. We observed marked seasonal and vertical variations in picocyanobacteria, bacteria and virus abundances and production. The contribution of picoplankton and nanoplankton production to the total primary production was high (reaching up to 76% of total primary production) in November and the spring–summer transition period, respectively. The impact of viral lysis on both bacteria and picocyanobacteria was significantly higher than grazing activities. Virus-induced picocyanobacterial mortality reached up to 66% of cell removal compared to virus induced (heterotrophic) bacterial mortality, which reached a maximum of 34% in July. Statistical analyzes revealed that temperature and top-down control by viruses are among important factors regulating the picocyanobacterial dynamics in this lake. More generally speaking, our results add to the growing evidence and accepted view nowadays that viruses are an important actor of freshwater microbial dynamics and more globally of the functioning of the microbial food webs

Prospective study of histopathological patterns of ovarian tumours in a tertiary care centre

Background:Ovarian tumours account for 3% of all cancers amongst women, being the second most common cancer of the female genital tract. The ovarian tumours are highly heterogenous with a wide range of histological patterns. Aim of current study was to study the histological patterns and the age incidence of the ovarian tumours in our institute.Methods:The present study is a prospective study conducted in the department of pathology, Andhra Medical College, from August 2011 to July 2013.Results:We received a total of 267 specimens of ovarian tumours during this period, out of which, 263 were primary and 4 were secondary tumours. Benign tumours were 209 (78.3%), borderline were 10 (3.7%) and malignant were 48 (18%) in numbers. Overall surface epithelial tumours constituted the majority of tumours accounting for 214 (80.2%) cases, followed by germ cell tumours 38 (14.2%) and sexcord stromal tumours 11 (4.1%). The single most common tumour diagnosed was serous cystadenoma. The most common malignant tumour was serous cystadenocarcinoma. The age groups affected ranged from 11-70 years. The peak age incidences for different histological types were as follows: surface epithelial tumours: 21-50 years, germ cell tumours: 21-30 years, sexcord stromal tumours: 51-60years. Benign tumours were more common in 21-40 years of age, borderline in 31-50 years and malignant tumours in 41-50 years age group.Conclusion:The results from our study were comparable with those reported in literature; however malignant serous and mucinous tumours showed a lower peak age incidence in our study. Krukenberg tumours also occurred in younger age group in our study.