192 research outputs found

    Evaluation of Sentinel Node Biopsy in Locally Advanced Breast Cancer Patients Who Become Clinically Node-Negative after Neoadjuvant Chemotherapy: A Preliminary Study

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    Introduction. Controversy continues over the appropriate timing of sentinel lymph node (SLN) biopsy in locally advanced breast cancer (LABC) patients receiving neoadjuvant chemotherapy. We evaluated the feasibility and accuracy of SLN biopsy in LABC patients with cytology-proven axillary nodal metastasis who become clinically node-negative after neoadjuvant chemotherapy. Materials. 30 consecutive patients with LABC, who had become clinically node-negative after 3 cycles of neoadjuvant chemotherapy, were included in the study. They were then subjected to SLN biopsy, axillary lymph node dissection, and breast surgery. Results. Sentinel nodes were successfully identified in 26 of the 30 patients, resulting in an identification rate of 86.67%, sensitivity of 83.33%, false negative rate of 20%, negative predictive value of 72.73%, and an overall accuracy of 88.46%. No complications were observed as a result of dye injection. Conclusions. SLN biopsy is feasible and safe in LABC patients with cytology-positive nodes who become clinically node-negative after neoadjuvant chemotherapy. Our accuracy rate, identification rate, and false negative rate are comparable to those in node-negative LABC patients. SLN biopsy as a therapeutic option in LABC after neoadjuvant chemotherapy is a promising option which should be further investigated

    Effects of Ply Stacking Sequence in 3D Fiber Reinforced Foam Core Sandwich Structures with Defects

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140407/1/6.2014-0504.pd

    Revision total knee arthroplasty in the young patient: is there trouble on the horizon?

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    BACKGROUND: The volume of total knee arthroplasties, including revisions, in young patients is expected to rise. The objective of this study was to compare the reasons for revision and re-revision total knee arthroplasties between younger and older patients, to determine the survivorship of revision total knee arthroplasties, and to identify risk factors associated with failure of revision in patients fifty years of age or younger. METHODS: Perioperative data were collected for all total knee arthroplasty revisions performed from August 1999 to December 2009. A cohort of eighty-four patients who were fifty years of age or younger and a cohort of eighty-four patients who were sixty to seventy years of age were matched for the date of surgery, sex, and body mass index (BMI). The etiology of failure of the index total knee arthroplasty and all subsequent revision total knee arthroplasties was determined. Kaplan-Meier survival curves were used to evaluate the timing of the primary failure and the survivorship of revision knee procedures. Finally, multivariate Cox regression was used to calculate risk ratios for the influence of age, sex, BMI, and the reason for the initial revision on survival of the revision total knee arthroplasty. RESULTS: The most common reason for the initial revision was aseptic loosening (27%; 95% confidence interval [CI] = 19% to 38%) in the younger cohort and infection (30%; 95% CI = 21% to 40%) in the older cohort. Of the twenty-five second revisions in younger patients, 32% (95% CI = 17% to 52%) were for infection, whereas 50% (95% CI = 32% to 68%) of the twenty-six second revisions in the older cohort were for infection. Cumulative six-year survival rates were 71.0% (95% CI = 60.7% to 83.0%) and 66.1% (95% CI = 54.5% to 80.2%) for revisions in the younger and older cohorts, respectively. Infection and a BMI of ≥40 kg/m2 posed the greatest risk of failure of revision procedures, with risk ratios of 2.731 (p = 0.006) and 2.934 (p = 0.009), respectively. CONCLUSIONS: The survivorship of knee revisions in younger patients is a cause of concern, and the higher rates of aseptic failure in these patients may be related to unique demands that they place on the reconstruction. Improvement in implant fixation and treatment of infection when these patients undergo revision total knee arthroplasty is needed. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence

    Composite Structures Damage Tolerance Analysis Methodologies

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    This report presents the results of a literature review as part of the development of composite hardware fracture control guidelines funded by NASA Engineering and Safety Center (NESC) under contract NNL04AA09B. The objectives of the overall development tasks are to provide a broad information and database to the designers, analysts, and testing personnel who are engaged in space flight hardware production

    Markedly disturbed sleep in medically refractory compared to controlled epilepsy – A clinical and polysomnography study

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    AbstractPurposeTo evaluate sleep disturbances or sleep related events and their characteristics among patients with medically refractory epilepsy, compared to those with controlled epilepsy.MethodsIn a prospective case-controlled study, patients of medically refractory and controlled epilepsy were recruited and history pertaining to epilepsy and sleep related events and Epworth sleepiness scores were recorded and all patients underwent over night polysomnography.ResultsAmong 40 patients, 20 with medically refractory (Group 1) and 20 with controlled epilepsy (Group 2) (median age 18, range 10–35 years), the self reported sleep parameters in Group 1 patients were found to be significantly different as compared to Group 2, in terms of the duration of night time sleep, day time sleep, day time nap frequency, total sleep hours per day, excessive daytime sleepiness (EDS)(45% vs. 15%) and average sleep hours over the week prior to polysomnography. On PSG, Group 1 patients showed significantly less total sleep time [340.4min (147–673) vs. 450.3min (330–570)] with delayed sleep latency and REM latency, poor sleep efficiency [80.45 (40.5–98.0) vs. 95.45 (88.4–99.7)] and frequent arousals and wake after sleep onset (WASO) compared to Group 2 patients. Four patients (20%) in Group 1 compared to none in Group 2 were found to have mild obstructive sleep apnea.ConclusionsOur results indicate that medically refractory epilepsy patients believe that they spend more time sleeping, in contrast to the documented shorter sleep duration on polysomnography. This difference between perceived and actual sleep seems, by their data, to arise mainly from sleep fragmentation, disturbed architecture and the interesting finding of associated sleep apnea among the medically refractory epilepsy patients

    FAILURE ANALYSIS OF THE ARECIBO OBSERVATORY M4N AUXILIARY CABLE

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    Structural and forensic analysis concluded that the Arecibo Observatory M4N socket joint failure in August 2020 was due to a socket joint design with insufficient design criteria that did not explicitly consider socket constituent stress margins or time-dependent damage mechanisms. The socket attachment design was found to have an initially low structural margin with a finite service life, notably in the outer socket wires, which degraded primarily due to long-term zinc creep effects that were activated by longterm sustained loading and exacerbated by cyclic loading. Additionally, HAC and wire defects were found in a few outer wires that may also have contributed to initial outer wire failures. The design did not explicitly consider the time-dependent effects of creep and cyclic loading on design capability, account for a worstcase build condition traceable to in-service inspection of features (e.g., zinc creep/extrusion), specify an end-of-life capability requirement associated with service life degradation, or explicitly set service life inspection intervals with pass/fail inspection criteria. In-service inspections showed evidence of progressive zinc extrusion on several Arecibo sockets, which in hindsight were evidence of cumulative damage and effectively a missed opportunity to prevent cable failure. Open spelter sockets of this type are used throughout industry in stay cables. The following recommendations are proposed to prevent failures of similar socket joints: (1) Verification of positive stress margins in socket joint wires for all failure modes, (2) Periodic visual inspections with acceptance criteria for zinc extrusion that are tied to structural qualification, (3) Revisiting civil codes and industry standards based on lessons learned from this analysis.&nbsp

    Modeling Failure of 3D Fiber Reinforced Foam Core Sandwich Structures with Defects

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97072/1/AIAA2012-1863.pd

    A blockchain and deep neural networks-based secure framework for enhanced crop protection

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    The problem faced by one farmer can also be the problem of some other farmer in other regions. Providing information to farmers and connecting them has always been a challenge. Crowdsourcing and community building are considered as useful solutions to these challenges. However, privacy concerns and inactivity of users can make these models inefficient. To tackle these challenges, we present a cost-efficient and blockchain-based secure framework for building a community of farmers and crowdsourcing the data generated by them to help the farmers’ community. Apart from ensuring privacy and security of data, a revenue model is also incorporated to provide incentives to farmers. These incentives would act as a motivating factor for the farmers to willingly participate in the process. Through integration of a deep neural network-based model to our proposed framework, prediction of any abnormalities present within the crops and their predicted possible solutions would be much more coherent. The simulation results demonstrate that the prediction of plant pathology model is highly accurate

    Cancer burden and alarm signals: a community based study from Kerala, India

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    Background: Cancer is emerging as a major public health concern in many countries including India. Kerala state has the highest burden of cancer in the country. Objective of this study was to estimate the prevalence of diagnosed cancers, warning signs and selected risk factors of cancer in Kadapra Panchayath of Pathanamthitta district, Kerala.Methods: A total of 16,391 population was covered by door to door survey using a structured questionnaire. The questionnaire collected information on the sociodemographic variables of the residents, source of water supply, warning signs of cancer and details of diagnosed cancer cases.Results: The mean age of the population was 40.9+21 years. The prevalence of diagnosed cases of cancer in our study population was 776/100,000 population. Breast cancer was the most common cancer (43.5%) identified in the population. The prevalence of any warning sign among the study population was 220/100,000 population. Breast lump was the common warning sign identified. Increasing age and female gender were the factors found to be significantly associated with cancer.Conclusions: As prevalence of cancer was found to be high in this population, an active community based screening along with teaching self-breast examination to the women in the community are required. Improving community awareness could help in early diagnosis, treatment and prevention. Soil and water testing for carcinogens is recommended
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