2,058 research outputs found

    Auto-Zero Differential Amplifier

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    An autozero amplifier may include a window comparator network to monitor an output offset of a differential amplifier. The autozero amplifier may also include an integrator to receive a signal from a latched window comparator network, and send an adjustment signal back to the differential amplifier to reduce an offset of the differential amplifier

    BREAST CANCER DIAGNOSIS USING WRAPPER-BASED FEATURE SELECTION AND ARTIFICIAL NEURAL NETWORK

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    Breast cancer is commonest type of cancers among women. Early diagnosis plays a significant role in reducing the fatality rate. The main objective of this study is to propose an efficient approach to classify breast cancer tumor into either benign or malignant based on digitized image of a fine needle aspirate (FNA) of a breast mass represented by the Wisconsin Breast Cancer Dataset. Two wrapper-based feature selection methods, namely, sequential forward selection(SFS) and sequential backward selection (SBS) are used to identify the most discriminant features which can contribute to improve the classification performance. The feed forward neural network (FFNN) is used as a classification algorithm. The learning algorithm hyper-parameters are optimized using the grid search process. After selecting the optimal classification model, the data is divided into training set and testing set and the performance was evaluated. The feature space is reduced from nine feature to seven and six features using SFS and SBS respectively. The highest classification accuracy recorded was 99.03% with FFNN using the seven SFS selected features. While accuracy recorded with the six SBS selected features was 98.54%. The obtained results indicate that the proposed approach is effective in terms of feature space reduction leading to better accuracy and efficient classification model

    Clinical, pathological and molecular factors predicting Axillary Node involvement in primary Breast Cancer in Pakistani women

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    Background: Axillary lymph node involvement in primary breast cancer is one of its most important prognostic features. Thus any factors that may predict axillary lymph node involvement in this setting could be potentially helpful in treatment planning and other interventions. Objective: The objective of this study was to evaluate clinical, pathological and immuno-histochemical markers in univariate and multivariate analysis, which may be helpful predictors of axillary lymph node involvement in breast cancer. Method: A retrospective analysis of 555 cases. Of these 58% had axillary nodal positivity and 42% were negative. Conclusion: Factors of no significance included patient’s age, height, weight, age of first pregnancy, parity, marital status, menopausal status, family history of breast cancer, side of tumor. In univariate analysis the age of menarche, duration of symptoms, tumor size, site in outer quadrant, S phase and skin and nipple involvement all predicted axillary nodal involvement. The length of breast-feeding, increased intraductal component and increased PCNA were inversely proportional to nodal involvement. In multiple regression analysis however only size of the tumor, involvement of the skin and nipple and disease in the outer quadrant of breast were the factors, which assumed significanc

    The molecular basis of host specialization in bean pathovars of Pseudomonas syringae

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    Biotrophic phytopathogens are typically limited to their adapted host range. In recent decades, investigations have teased apart the general molecular basis of intraspecific variation for innate immunity of plants, typically involving receptor proteins that enable perception of pathogen-associated molecular patterns or avirulence elicitors from the pathogen as triggers for defense induction. However, general consensus concerning evolutionary and molecular factors that alter host range across closely related phytopathogen isolates has been more elusive. Here, through genome comparisons and genetic manipulations, we investigate the underlying mechanisms that structure host range across closely related strains of Pseudomonas syringae isolated from different legume hosts. Although type III secretionindependent virulence factors are conserved across these three strains, we find that the presence of two genes encoding type III effectors (hopC1 and hopM1) and the absence of another (avrB2) potentially contribute to host range differences between pathovars glycinea and phaseolicola. These findings reinforce the idea that a complex genetic basis underlies host range evolution in plant pathogens. This complexity is present even in host–microbe interactions featuring relatively little divergence among both hosts and their adapted pathogens

    Not just bricks and mortar: planning hospital cancer services for Aboriginal people

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    <p>Abstract</p> <p>Background</p> <p>Aboriginal people in Australia experience higher mortality from cancer compared with non-Aboriginal Australians, despite an overall lower incidence. A notable contributor to this disparity is that many Aboriginal people do not take up or continue with cancer treatment which almost always occurs within major hospitals.</p> <p>Thirty in-depth interviews with urban, rural and remote Aboriginal people affected by cancer were conducted between March 2006 and September 2007. Interviews explored participants' beliefs about cancer and experiences of cancer care and were audio-recorded, transcribed verbatim and coded independently by two researchers. NVivo7 software was used to assist data management and analysis. Information from interviews relevant to hospital services including and building design was extracted.</p> <p>Findings</p> <p>Relationships and respect emerged as crucial considerations of participants although many aspects of the hospital environment were seen as influencing the delivery of care. Five themes describing concerns about the hospital environment emerged: (i) being alone and lost in a big, alien and inflexible system; (ii) failure of open communication, delays and inefficiency in the system; (iii) practicalities: costs, transportation, community and family responsibilities; (iv) the need for Aboriginal support persons; and (v) connection to the community.</p> <p>Conclusions</p> <p>Design considerations and were identified but more important than the building itself was the critical need to build trust in health services. Promotion of cultural safety, support for Aboriginal family structures and respecting the importance of place and community to Aboriginal patients are crucial in improving cancer outcomes.</p

    Factors contributing to delayed diagnosis of cancer among Aboriginal people in Australia: a qualitative study.

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    BACKGROUND/OBJECTIVES: Delayed presentation of symptomatic cancer is associated with poorer survival. Aboriginal patients with cancer have higher rates of distant metastases at diagnosis compared with non-Aboriginal Australians. This paper examined factors contributing to delayed diagnosis of cancer among Aboriginal Australians from patient and service providers' perspectives. METHODS: In-depth, open-ended interviews were conducted in two stages (2006-2007 and 2011). Inductive thematic analysis was assisted by use of NVivo looking around delays in presentation, diagnosis and referral for cancer. PARTICIPANTS: Aboriginal patients with cancer/family members (n=30) and health service providers (n=62) were recruited from metropolitan Perth and six rural/remote regions of Western Australia. RESULTS: Three broad themes of factors were identified: (1) Contextual factors such as intergenerational impact of colonisation and racism and socioeconomic deprivation have negatively impacted on Aboriginal Australians' trust of the healthcare professionals; (2) health service-related factors included low accessibility to health services, long waiting periods, inadequate numbers of Aboriginal professionals and high staff turnover; (3) patient appraisal of symptoms and decision-making, fear of cancer and denial of symptoms were key reasons patients procrastinated in seeking help. Elements of shame, embarrassment, shyness of seeing the doctor, psychological 'fear of the whole health system', attachment to the land and 'fear of leaving home' for cancer treatment in metropolitan cities were other deterrents for Aboriginal people. Manifestation of masculinity and the belief that 'health is women's domain' emerged as a reason why Aboriginal men were reluctant to receive health checks. CONCLUSIONS: Solutions to improved Aboriginal cancer outcomes include focusing on the primary care sector encouraging general practitioners to be proactive to suspicion of symptoms with appropriate investigations to facilitate earlier diagnosis and the need to improve Aboriginal health literacy regarding cancer. Access to health services remains a critical problem affecting timely diagnosis

    Ethnobotanical studies on Berberis aristata DC. root extracts

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    The aqueous and alcoholic extract of fresh Berberis aristata DC roots, as well as aqueous extract of dried roots were compared for their antibacterial and antifungal activities by the disc diffusion method.All three extracts showed wide antibacterial activity against Gram-positive bacteria. Among the Gramnegative bacteria tested, the antibacterial activity was limited to Escherichia coli, Salmonellatyphimurium, Shigella dysenteriae type 1 and Vibrio cholerae; with the best activity against V. cholerae. MICs of the alcoholic extracts against Gram-positive bacteria ranged between 3.8 ×10-3 to 6.1 ×10-3 mg/ml and for Gram-negative bacteria from 6.1 ×10-3 to 7.6 10-3 mg/ml. The MICs for Candida species ranged between 0.02 to 3.8 ×10-3 mg/ml and for Aspergillus species, it was 3 × 10-3 mg/ml. All three extracts also had antifungal activity against the fungal species tested, except Candida krusei. The extracts of B. aristata also demonstrated anti-inflammatory, analgesic, and antipyretic activities.Chemical analysis revealed the presence of alkaloids, amino acids, tannins, terpenes, resins, phenols and reducing sugars as major compounds. FTIR-spectral analysis of all the extracts revealed thepresence of berberine, as a major constituent, along with other chemical constituents
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