474 research outputs found

    A survey on Routing Protocols in Wireless Sensor Networks

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    In ad-hoc WSN is a collection of mobile nodes that are dynamically and randomly located in such a manner that the interconnections between nodes are changing on a continual basis. The dynamic nature of these networks demands new set of network routing strategy protocols to be implemented in order to provide efficient end-to end communication. Moreover, such issues are very critical due to severe resource constraints like efficient energy utilization, lifetime of network, and drastic environmental conditions in WSNs. Neither hop-by-hop nor neither direct reach ability is possible in case of WSNs. In order to facilitate communication within the network, a routing protocol is used. In this paper we have carried out an extensive survey on WSN protocols based on structure of network, routing protocol of network & clustering techniques of routing protocols

    Primary Meningeal Rhabdomyosarcoma

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    Primary meningeal rhabdomyosarcoma is a rare primary brain malignancy, with scant case reports. While most reports of primary intracranial rhabdomyosarcoma occur in pediatric patients, a handful of cases in adult patients have been reported in the medical literature. We report the case of a 44-year-old male who developed primary meningeal rhabdomyosarcoma. After developing episodes of right lower extremity weakness, word finding difficulty, and headaches, a brain magnetic resonance imaging (MRI) demonstrated a vertex lesion with radiographic appearance of a meningeal-derived tumor. Subtotal surgical resection was performed due to sagittal sinus invasion and initial pathology was interpreted as an anaplastic meningioma. Re-review of pathology demonstrated rhabdomyosarcoma negative for alveolar translocation t(2;13). Staging studies revealed no evidence of disseminated disease. He was treated with stereotactic radiotherapy with concurrent temozolamide to be followed by vincristine, actinomycin-D, and cyclophosphamide (VAC) systemic therapy

    Investigation of common, low-frequency and rare genome-wide variation in anorexia nervosa

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    Correction: Volume: 23 Issue: 9 DOI: 10.1038/mp.2017.202 Published: SEP 2018Anorexia nervosa (AN) is a complex neuropsychiatric disorder presenting with dangerously low body weight, and a deep and persistent fear of gaining weight. To date, only one genome-wide significant locus associated with AN has been identified. We performed an exome-chip based genome-wide association studies (GWAS) in 2158 cases from nine populations of European origin and 15 485 ancestrally matched controls. Unlike previous studies, this GWAS also probed association in low-frequency and rare variants. Sixteen independent variants were taken forward for in silico and de novo replication (11 common and 5 rare). No findings reached genome-wide significance. Two notable common variants were identified: rs10791286, an intronic variant in OPCML (P = 9.89 x 10(-6)), and rs7700147, an intergenic variant (P = 2.93 x 10(-5)). No low-frequency variant associations were identified at genome-wide significance, although the study was well-powered to detect low-frequency variants with large effect sizes, suggesting that there may be no AN loci in this genomic search space with large effect sizes.Peer reviewe

    Midlife systemic inflammation is associated with frailty in later life: The ARIC study

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    Background: Evidence suggests that systemic inflammation may have a mechanistic role in age-related frailty, yet prospective data is limited. We examined whether systemic inflammation during midlife was associated with late-life frailty within the community-based Atherosclerosis Risk in Communities Study. Methods: Plasma levels of four inflammatory markers (fibrinogen, von Willebrand factor, and Factor VIII, and white blood cell count) were measured during Visit 1 (1987-1989; mean age: 52 [5]), standardized into z-scores, and combined to create an inflammation composite score. High-sensitivity C-reactive protein (CRP) was measured 3 (Visit 2, 1990-1992) and 9 (Visit 4, 1996-1999) years later. Frailty was evaluated in 5,760 participants during late life (Visit 5, 2011-2013; mean age: 75 [5]). Analyses were adjusted for demographic and physiological variables, and midlife medical comorbidity using logistic regression. Results: A 1 SD increase in midlife inflammation composite score was associated with higher odds of frailty 24 years later (odds ratio [OR] = 1.39, 95% confidence interval [CI]: 1.18-1.65). Similarly, each standard deviation increase in Visit 2 CRP (OR = 1.24, 95% CI: 1.09-1.40) and Visit 4 CRP (OR = 1.35, 95% CI: 1.19-1.53) was associated with a higher odds of frailty 21 and 15 years later. Participants who maintained elevated CRP (≥3 mg/L) at Visits 2 and 4 or transitioned to a state of elevated CRP during this period were more likely to subsequently meet frailty criteria compared to those who maintained low CRP. These associations were stronger among white, compared to African American, participants (p-interactions <.038). Conclusions: Systemic inflammation during midlife may independently promote pathophysiological changes underlying frailty in a subset of the population

    Prestroke Physical Activity and Adverse Health Outcomes after Stroke in the Atherosclerosis Risk in Communities Study

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    Background and Purpose: The association of physical activity (PA) before stroke (prestroke PA) with long-term prognosis after stroke is still unclear. We examined the association of prestroke PA with adverse health outcomes in the ARIC study (Atherosclerosis Risk in Communities). Methods: We included 881 participants with incident stroke occurring between 1993 and 1995 (visit 3) and December 31, 2016. Follow-up continued until December 31, 2017 to allow for at least 1-year after incident stroke. Prestroke PA was assessed using a modified version of the Baecke questionnaire in 1987 to 1989 (visit 1) and 1993 to 1995 (visit 3), evaluating PA domains (work, leisure, and sports) and total PA. We used Cox proportional hazards models to quantify the association between tertiles of accumulated prestroke PA levels over the 6-year period between visits 1 and 3 and mortality, risk of cardiovascular disease, and recurrent stroke after incident stroke. Results: During a median follow-up of 3.1 years after incident stroke, 676 (77%) participants had adverse outcomes. Highest prestroke total PA was associated with decreased risks of all-cause mortality (hazard ratio, 0.78 [95% CI, 0.63-0.97]) compared with lowest tertile. In the analysis by domain-specific PA, highest levels of work PA were associated with lower risk for all-cause (hazard ratio, 0.77 [95% CI, 0.62-0.96]) and cardiovascular mortality (hazard ratio, 0.45 [95% CI, 0.29-0.70]), and highest levels of leisure PA were associated with lower all-cause mortality (hazard ratio, 0.72 [95% CI, 0.58-0.89]) compared with lowest tertile of PA. No significant associations for sports PA were observed. Conclusions: Higher levels of total prestroke PA as well as work and leisure PA were associated with lower risk of mortality after incident stroke. Public health strategies to increase lifetime PA should be encouraged to decrease long-term mortality after stroke

    Clinically Recognized Varicose Veins and Physical Function in Older Individuals: The ARIC Study

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    BACKGROUND: Although a few studies reported an association between varicose veins and physical function, this potentially bidirectional association has not been systematically evaluated in the general population. METHOD: In 5 580 participants (aged 71-90 years) from the Atherosclerosis Risk in Communities study, varicose veins were identified in outpatient and inpatient administrative data prior to (prevalent cases) and after (incident cases) visit 5 (2011-2013). Physical function was evaluated by the Short Physical Performance Battery (SPPB, score ranging from 0 to 12). We evaluated (i) cross-sectional association between prevalent varicose veins and physical function, (ii) association of prevalent varicose veins with subsequent changes in physical function from visit 5 to visits 6 (2016-2017) and 7 (2018-2019), and (iii) association of physical function at visit 5 with incident varicose veins during a median follow-up of 3.6 years (105 incident varicose veins among 5 350 participants without prevalent cases at baseline). RESULTS: At baseline, varicose veins were recognized in 230 (4.1%) participants and cross-sectionally associated with reduced physical function. Longitudinally, prevalent varicose veins were not significantly associated with a decline in SPPB over time. In contrast, a low SPPB ≤6 was associated with a greater incidence of varicose veins compared to SPPB ≥10 (adjusted hazard ratio 2.13 [95% confidence interval = 1.19, 3.81]). CONCLUSION: In community-dwelling older adults, varicose veins and low physical function were associated cross-sectionally. Longitudinally, low physical function was a risk factor for incident varicose veins, but not vice versa. Our findings suggest an etiological contribution of low physical function to incident varicose veins

    Life's Simple 7 at Midlife and Risk of Recurrent Cardiovascular Disease and Mortality after Stroke: The ARIC study

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    Background: Stroke is a leading cause of morbidity and mortality among adults in the U.S. Ideal levels of the Life's Simple 7 (LS7) are associated with lower cardiovascular disease (CVD) and all-cause mortality. However, the association of LS7 with CVD, recurrent stroke, and all-cause mortality after incident stroke is unknown. Methods: We used data from the ARIC study, a cohort of 13,508 adults from four US communities, 45–64 years old at baseline (1987–1989). Cardiovascular hospitalizations and mortality were ascertained in follow-up through December 31st, 2017. We defined cardiovascular health (CVH) based on AHA definitions for LS7 (range 0-14) and categorized CVH into four levels: LS7 0-3, 4-6, 7-9, and ≥10 (ideal LS7), according to prior studies. Outcomes included incident stroke, CVD, recurrent stroke, all-cause mortality, and a composite outcome including all the above. Adjusted hazard ratios (95% CI) were estimated with Cox proportional hazards regression models. Results: Median (25%-75%) follow-up for incident stroke was 28 (18.6-29.2) years. Participants with incident stroke were 55.7 (SD 5.6) years-old at baseline, 53% were women and 35% Black. Individuals with LS7 score ≥10 had 65% lower risk (HR: 0.35; 95% CI: 0.29-0.41) of incident stroke than those with LS7 4-6 (reference group). Of 1,218 participants with incident stroke, 41.2% (n=502) had composite CVD and 68.3% (n=832) died during a median (25%-75%) follow-up of 4.0 (0.76-9.95) years. Adjusted HR (95% CI) for stroke survivors with LS7≥10 at baseline were 0.74 (0.58-0.94) for the composite outcome, 0.38(0.17-0.85) for myocardial infarction, 0.60 (0.40-0.90) for heart failure, 0.63 (0.48-0.84) for all-cause mortality, and 0.65 (0.39-1.08) for recurrent stroke. Conclusions: Good and excellent midlife cardiovascular health are associated with lower risks of incident stroke and CVD after stroke. Clinicians should stress the importance of a healthy lifestyle for primary and secondary CVD prevention

    Loneliness and its predictors among older adults prior to and during the COVID-19 pandemic: Cross-sectional and longitudinal survey findings from participants of the Atherosclerosis Risk in Communities (ARIC) Study cohort in the USA

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    Objectives We aimed to ascertain the prevalence of perceived loneliness among older adults following the onset of the COVID-19 pandemic and to examine factors contributing to the perception of loneliness. Design Cross-sectional and longitudinal data from the Atherosclerosis Risk in Communities (ARIC) Study cohort. Setting The ARIC Study cohort, a prospective cohort that recruited (1987-1989) participants from four distinct communities in the USA. Participants 2984 ARIC cohort members. Primary and secondary outcomes Perceived loneliness assessed using the University of California at Los Angeles (UCLA) UCLA three-item Loneliness Scale telephone interviews conducted May-October 2020 and prior to March 2020. Results Of the total 5037 participants alive in 2020, 2984 (56.2%) responded to the UCLA three-item questionnaire (mean age 82.6 (SD 4.6) years, 586 (19.6%) black participants, 1081 (36.2%) men), of which 66 (2.2%) reported having had a COVID-19 infection during the observation period. The proportion of participants reporting feeling lonely was 56.3% (n=1680). Among participants with repeat measures of loneliness (n=516), 35.2% (n=182) reported feeling more lonely following pandemic onset. Self-rated health and emotional resilience were strongly associated with self-perceived loneliness. The burden of COVID-19 infections, concern about the pandemic and decreased self-reported physical activity were greater among black as compared with white participants and among those with an educational attainment of less than high school as compared with high school or more. Conclusion Findings from this study document the increase in perceived loneliness among older adults during the COVID-19 pandemic in the USA

    Safety and acceptability of an organic light-emitting diode sleep mask as a potential therapy for retinal disease

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    Purpose The purpose of the study was to study the effect of an organic light-emitting diode sleep mask on daytime alertness, wellbeing, and retinal structure/function in healthy volunteers and in diabetic macular oedema (DMO). Patients and methods Healthy volunteers in two groups, 18–30 yrs (A), 50–70 yrs (B) and people with DMO (C) wore masks (504 nm wavelength; 80 cd/m2 luminance; ≤8 h) nightly for 3 months followed by a 1-month recovery period. Changes from baseline were measured for (means): psychomotor vigilance task (PVT) (number of lapses (NL), response time (RT)), sleep, depression, psychological wellbeing (PW), visual acuity, contrast sensitivity, colour, electrophysiology, microperimetry, and retinal thickness on OCT. Results Of 60 participants, 16 (27%) withdrew, 8 (13%) before month 1, due to sleep disturbances and mask intolerance. About 36/55 (65%) who continued beyond month 1 reported ≥1 adverse event. At month 3 mean PVT worsened in Group A (RT (7.65%, P<0.001), NL (43.3%, P=0.005)) and mean PW worsened in all groups (A 28.0%, P=0.01, B 21.2%, P=0.03, C 12.8%, P<0.05). No other clinically significant safety signal was detected. Cysts reduced/resolved in the OCT subfield of maximal pathology in 67% Group C eyes. Thinning was greater at 3 and 4 months for greater baseline thickness (central subfield P<0.001, maximal P<0.05). Conclusion Sleep masks showed no major safety signal apart from a small impairment of daytime alertness and a moderate effect on wellbeing. Masks were acceptable apart from in some healthy participants. Preliminary data suggest a beneficial effect on retinal thickness in DMO. This novel therapeutic approach is ready for large clinical trials
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