Optical fiber flow sensor based on a lever-hinge configuration.

Based on a lever-hinge structure, a target-type fiber Bragg grating (FBG) flow sensor is proposed. Differential measurements of temperature and pressure are achieved using two FBGs. The design idea of the sensor is demonstrated from both theoretical and experimental aspects, and the relationship between FBG wavelength and temperature and the relationship between FBG wavelength and volume flow rate were established, respectively. The sensor is compact with good resolution, high stability, wide measurement range, and easy fabrication, and can be applied to measure temperature and volume flow rate in injection wells.

Design and fabrication of a differential-pressure optical fiber grating sensor for monitoring the flow rate of fluid.

A fiber Bragg grating (FBG) flow sensor is designed and fabricated, in which two FBGs are fixed on the front and other side of the metal diaphragm, and differential pressure is used to monitor the flow rate of fluid. The temperature sensitivity of these two FBGs is 0.030 and 0.029 nm/°C, which is almost the same, suggesting that the influence of temperature on the flow measurement can be effectively eliminated. The static pressure sensitivity of these two FBGs can be up to 86.7 nm/MPa and 68.6 nm/MPa, respectively; accordingly, the static pressure sensitivity of the sensor overall is 155.3 nm/MPa. Furthermore, the flow rate sensitivity is 0.00029 L/s. This FBG flow sensor exhibits high sensitivity, high accuracy, and a low start-up flow rate. Furthermore, the cross effect between the temperature and strain on the sensing sensitivity is eliminated, which makes this FBG flow sensor suitable for real-time monitoring of the trace flow rate in oil and gas wells.

Probing allosteric coupling in a constitutively open mutant of the ion channel KcsA using solid-state NMR.

Transmembrane allosteric coupling is a feature of many critical biological signaling events. Here we test whether transmembrane allosteric coupling controls the potassium binding affinity of the prototypical potassium channel KcsA in the context of C-type inactivation. Activation of KcsA is initiated by proton binding to the pH gate upon an intracellular drop in pH. Numerous studies have suggested that this proton binding also prompts a conformational switch, leading to a loss of affinity for potassium ions at the selectivity filter and therefore to channel inactivation. We tested this mechanism for inactivation using a KcsA mutant (H25R/E118A) that exhibits an open pH gate across a broad range of pH values. We present solid-state NMR measurements of this open mutant at neutral pH to probe the affinity for potassium at the selectivity filter. The potassium binding affinity in the selectivity filter of this mutant, 81 mM, is about four orders of magnitude weaker than that of wild-type KcsA at neutral pH and is comparable to the value for wild-type KcsA at low pH (pH ≈ 3.5). This result strongly supports our assertion that the open pH gate allosterically affects the potassium binding affinity of the selectivity filter. In this mutant, the protonation state of a glutamate residue (E120) in the pH sensor is sensitive to potassium binding, suggesting that this mutant also has flexibility in the activation gate and is subject to transmembrane allostery.

Cost-Effectiveness of Screening Mammography Beyond Age 75 Years : A Cost-Effectiveness Analysis.

BACKGROUND: The cost-effectiveness of screening mammography beyond age 75 years remains unclear. OBJECTIVE: To estimate benefits, harms, and cost-effectiveness of extending mammography to age 80, 85, or 90 years according to comorbidity burden. DESIGN: Markov microsimulation model. DATA SOURCES: SEER (Surveillance, Epidemiology, and End Results) program and Breast Cancer Surveillance Consortium. TARGET POPULATION: U.S. women aged 65 to 90 years in groups defined by Charlson comorbidity score (CCS). TIME HORIZON: Lifetime. PERSPECTIVE: National health payer. INTERVENTION: Screening mammography to age 75, 80, 85, or 90 years. OUTCOME MEASURES: Breast cancer death, survival, and costs. RESULTS OF BASE-CASE ANALYSIS: Extending biennial mammography from age 75 to 80 years averted 1.7, 1.4, and 1.0 breast cancer deaths and increased days of life gained by 5.8, 4.2, and 2.7 days per 1000 women for comorbidity scores of 0, 1, and 2, respectively. Annual mammography beyond age 75 years was not cost-effective, but extending biennial mammography to age 80 years was ($54 000, $65 000, and $85 000 per quality-adjusted life-year [QALY] gained for women with CCSs of 0, 1, and ≥2, respectively). Overdiagnosis cases were double the number of deaths averted from breast cancer. RESULTS OF SENSITIVITY ANALYSIS: Costs per QALY gained were sensitive to changes in invasive cancer incidence and shift of breast cancer stage with screening mammography. LIMITATION: No randomized controlled trials of screening mammography beyond age 75 years are available to provide model parameter inputs. CONCLUSION: Although annual mammography is not cost-effective, biennial screening mammography to age 80 years is; however, the absolute number of deaths averted is small, especially for women with comorbidities. Women considering screening beyond age 75 years should weigh the potential harms of overdiagnosis versus the potential benefit of averting death from breast cancer. PRIMARY FUNDING SOURCE: National Cancer Institute and National Institutes of Health.

Frailty and risk of mortality in older cancer survivors and adults without a cancer history: Evidence from the National Health and Nutrition Examination Survey, 1999-2014.

BACKGROUND: Epidemiologic evidence reporting the role of frailty in survival among older adults with a prior cancer diagnosis is limited. METHODS: A total of 2050 older adults (≥60 years old) surviving for at least 1 year after a cancer diagnosis and 9474 older adults without a cancer history from the National Health and Nutrition Examination Survey (1999-2014) were included for analysis. The exposure variable, a 45-item frailty index (FI), was categorized on the basis of validated cutoffs (FI ≤ 0.10 [fit], 0.10 < FI ≤ 0.21 [prefrail], and FI > 0.21 [frail]). All-cause mortality was ascertained via the National Death Index. Multivariable Cox proportional hazards models were used to estimate adjusted hazard ratios (aHRs) and 95% confidence interval (CIs) for the FI, and this was followed by restricted cubic splines depicting dose-response curves. RESULTS: For older cancer survivors, the mean age at the baseline was 72.6 years (SD, 7.1 years); 5.9% were fit, 38.2% were prefrail, and 55.9% were frail. Older adults without a cancer history were slightly younger (mean age, 70.0 years) and less frail (47.9% were frail). At each level of the FI, cancer survivors (1.9 per 100 person-years for FI ≤ 0.10, 3.4 per 100 person-years for 0.10 < FI ≤ 0.21, and 7.5 per 100 person-years for FI > 0.21) had higher mortality than their cancer-free counterparts (1.4 per 100 person-years for FI ≤ 0.10, 2.4 per 100 person-years for 0.10 < FI ≤ 0.21, and 5.4 per 100 person-years for FI > 0.21). The multivariable model suggested a positive association between the FI and all-cause mortality for survivors (aHR for FI > 0.21 vs FI ≤ 0.10, 2.80; 95% CI, 1.73-4.53) and participants without a cancer history (aHR for FI > 0.21 vs FI ≤ 0.10, 2.75; 95% CI, 2.29-3.32). Restricted cubic splines indicated that all-cause mortality risk increased with the FI in a monotonic pattern. CONCLUSIONS: Frailty is associated with a higher risk of death in older cancer survivors and the elderly without a cancer history.

Mammography adherence in relation to function-related indicators in older women.

Prior studies of screening mammography patterns by functional status in older women show inconsistent results. We used Breast Cancer Surveillance Consortium-Medicare linked data (1999-2014) to investigate the association of functional limitations with adherence to screening mammography in 145,478 women aged 66-74 years. Functional limitation was represented by a claims-based function-related indicator (FRI) score which incorporated 16 items reflecting functional status. Baseline adherence was defined as mammography utilization 9-30 months after the index screening mammography. Longitudinal adherence was examined among women adherent at baseline and defined as time from the index mammography to end of the first 30-month gap in mammography. Multivariable logistic regression and Cox proportional hazards models were used to investigate baseline and longitudinal adherence, respectively. Subgroup analyses were conducted by age (66-70 vs. 71-74 years). Overall, 69.6% of participants had no substantial functional limitation (FRI score 0), 23.5% had some substantial limitations (FRI score 1), and 6.8% had serious limitations (FRI score ≥ 2). Mean age at baseline was 68.5 years (SD = 2.6), 85.3% of participants were white, and 77.1% were adherent to screening mammography at baseline. Women with a higher FRI score were more likely to be non-adherent at baseline (FRI ≥ 2 vs. 0: aOR = 1.13, 95% CI = 1.06, 1.20, p-trend < 0.01). Similarly, a higher FRI score was associated with longitudinal non-adherence (FRI ≥ 2 vs. 0: aHR = 1.16, 95% CI = 1.11, 1.22, p-trend < 0.01). Effect measures of FRI did not differ substantially by age categories. Older women with a higher burden of functional limitations are less likely to be adherent to screening mammography recommendations.

Identifying coupled clusters of allostery participants through chemical shift perturbations.

Allosteric couplings underlie many cellular signaling processes and provide an exciting avenue for development of new diagnostics and therapeutics. A general method for identifying important residues in allosteric mechanisms would be very useful, but remains elusive due to the complexity of long-range phenomena. Here, we introduce an NMR method to identify residues involved in allosteric coupling between two ligand-binding sites in a protein, which we call chemical shift detection of allostery participants (CAP). Networks of functional groups responding to each ligand are defined through correlated NMR perturbations. In this process, we also identify allostery participants, groups that respond to both binding events and likely play a role in the coupling between the binding sites. Such residues exhibit multiple functional states with distinct NMR chemical shifts, depending on binding status at both binding sites. Such a strategy was applied to the prototypical ion channel KcsA. We had previously shown that the potassium affinity at the extracellular selectivity filter is strongly dependent on proton binding at the intracellular pH sensor. Here, we analyzed proton and potassium binding networks and identified groups that depend on both proton and potassium binding (allostery participants). These groups are viewed as candidates for transmitting information between functional units. The vital role of one such identified amino acid was validated through site-specific mutagenesis, electrophysiology functional studies, and NMR-detected thermodynamic analysis of allosteric coupling. This strategy for identifying allostery participants is likely to have applications for many other systems.

Patterns of de-novo metastasis and breast cancer-specific mortality by race and molecular subtype in the SEER population-based dataset.

PURPOSE: To examine patterns of de-novo metastases (mets) and association with breast cancer-specific mortality across subtypes and racial groups. METHODS: Non-Hispanic (NH) Black and NH-White patients ages 40 years and older with primary breast cancer (BC) between 2010 and 2015 were examined. Multilevel logistic regression and Cox proportional hazards models were used to assess (1) odds of de-novo mets to specific sites by subtype, and (2) association of subtype with risk of BC mortality among patients with de-novo mets by race. RESULTS: A total of 204,941 BC patients were included in analysis. The most common de-novo mets site was to the bone, and overall prevalence of de-novo mets was higher among NH-Black (6.4%) versus NH-White (4.1%) patients. The odds of de-novo mets to any site were lower for TNBC (OR 0.68, 95% CI 0.62-0.73) and HR+/HER2- (OR 0.50, 95% CI 0.47-0.53) subtypes, but higher for HR-/HER2+ (OR 1.16, 95% CI 1.06-1.28) relative to HR+/HER2+ . De-novo mets to the brain only was associated with the highest mortality risk across all subtypes, ranging from a 13-fold increase (hazard ratio 13.45, 95% CI 5.03-35.96) for HR-/HER2+ to a 39-fold increase (hazard ratio 39.04, 95% CI 26.2-58.14) for HR+/HER2-. CONCLUSION: Site and fatality of de-novo mets vary by subtype and by race. This information may help improve risk stratification and post-diagnostic surveillance to ultimately reduce BC mortality.

The association between cognitive impairment and breast and colorectal cancer screening utilization.

BACKGROUND: Undergoing cancer screening is a debatable topic in patients with cognitive impairment. In this study, we aimed to examine the utilization and predictors of breast and colorectal cancer screening among screening eligible, cognitively impaired individuals. METHODS: We analyzed the 2018 and 2019 National Health Interview Survey data (n = 12,965 and 24,782, respectively) on individuals eligible for breast or colorectal cancer screening. We calculated the percentage of cancer screening eligible individuals who received mammogram or colonoscopy by cognitive impairment status. We used multivariable logistic regression to examine whether having a recent mammogram or colonoscopy differed by cognitive impairment status, adjusting for covariates. RESULTS: We observed a significantly lower percentage of mammogram use in the screening eligible, cognitively impaired (mild or severe) versus unimpaired women. Adjusting for the covariates, the cognitively impaired women, mild (odds ratio [OR] = 0.85; p = 0.015) or severe (OR = 0.54; p <  0.001), were less likely to have had a recent mammogram compared to the cognitively unimpaired women. Although statistically non-significant, the percentage of colonoscopy use in the screening eligible, cognitively impaired individuals were slightly higher than that in the cognitively unimpaired individuals. In the regression analysis, we found the cognitively impaired men, mild (OR = 0.79; p <  0.001) or severe (OR = 0.69; p = 0.038), were less likely to have had a recent colonoscopy compared to the cognitively unimpaired men. More studies are needed to examine the multilevel factors that underpin the difference in cancer screening utilization in this vulnerable population. CONCLUSION: Our results highlight the need for additional research to address utilization and effectiveness of cancer screening in individuals with cognitive impairment.

Fruit and vegetable consumptions in relation to frequent mental distress in breast cancer survivors.

PURPOSE: Evidence suggests that fruit and vegetable consumptions may improve mental health among general population. However, their associations among breast cancer survivors are unclear. We planned to investigate this association via a nationwide survey in the USA. METHODS: We identified 7988 breast cancer survivors from 2009 Behavioral Risk Factor Surveillance System (BRFSS). Fruit juice, fruit, and vegetable consumptions were categorized as ordinal variables to approximate tertiles. Survivors who were mentally unhealthy for at least 14 days in the past 30 days were defined as having frequent mental distress (FMD). Multivariable logistic regression treating FMD as the outcome was used to calculate adjusted odd ratios (aORs) and 95% confidence intervals (CIs) for exposures. Quadratic model was used to depict the dose-response pattern in primary analysis. Subgroup analyses by adverse lifestyle behaviors were conducted; Wald tests were used to examine if there were interactions between these factors and exposures in relation to FMD. RESULTS: Overall, 825 (10.3%) survivors had FMD. Mean age was 67.2 years, and 89.7% of survivors were white. Juice showed non-significant associations with FMD. Moderate (aOR = 0.81, 95% CI = 0.68-0.98) and high (aOR = 0.79, 95% CI = 0.63-0.98) fruit consumptions, as well as moderate vegetable consumption (aOR = 0.78, 95% CI = 0.64-0.94), were significantly and inversely associated with FMD. The dose-response curves were consistent with results in primary analysis. No interaction was identified for adverse lifestyle behaviors. CONCLUSION: Fruit and vegetable, but not fruit juice, show potential preventive effects against FMD among breast cancer survivors. The conclusion should be verified by studies with clear temporality in future.

Self-rated health in relation to fruit and vegetable consumption and physical activity among older cancer survivors.

PURPOSE: We aimed to investigate associations of self-rated health with fruit and vegetable consumption (FVC) and physical activity (PA) among older cancer survivors. METHODS: We used the 2017 Behavioral Risk Factor Surveillance System to identify cancer survivors ≥ 65 years (N = 2663). Self-reported FVC and PA were categorized as ordinal variables to approximate quartiles. Low general health (LGH) was defined as fair or poor self-rated health. A multivariable logistic regression treating LGH as the outcome was used to calculate adjusted odd ratios (aORs) and 95% confidence intervals (CIs) for FVC and PA. Restricted cubic spline depicted non-linear dose-response curves for FVC and PA. In comparative analysis, we used the same logistic regression and dose-response model to calculate ORs of FVC and PA in 73,134 people ≥ 65 years without cancer history. RESULTS: Overall, 470 (17.7%) survivors had LGH. Survivors' mean age was 73.3 years (SD = 5.2), 55.1% of them were female, and 95.4% self-reported as white. In cancer survivors, FVC was not associated with LGH (≥ 28 vs. < 14 times/week: aOR = 1.02, 95% CI = 0.75-1.39, p-trend = 0.50), whereas PA was inversely associated with LGH (≥ 30 vs. < 7 MET-hours/week: aOR = 0.55, 95% CI = 0.41-0.75, p-trend < 0.01). Dose-response curves demonstrated consistent association patterns. In comparative analysis, ORs of PA did not change substantially but we observed inverse association for FVC. CONCLUSIONS: An inverse association between PA and LGH was observed among older cancer survivors, but no significant association was obtained for FVC among them. Regular PA may maintain or indicate a favorable health in older cancer survivors, whereas impacts of FVC deserve further investigations.

Informing NMR experiments with molecular dynamics simulations to characterize the dominant activated state of the KcsA ion channel.

As the first potassium channel with an x-ray structure determined, and given its homology to eukaryotic channels, the pH-gated prokaryotic channel KcsA has been extensively studied. Nevertheless, questions related, in particular, to the allosteric coupling between its gates remain open. The many currently available x-ray crystallography structures appear to correspond to various stages of activation and inactivation, offering insights into the molecular basis of these mechanisms. Since these studies have required mutations, complexation with antibodies, and substitution of detergents in place of lipids, examining the channel under more native conditions is desirable. Solid-state nuclear magnetic resonance (SSNMR) can be used to study the wild-type protein under activating conditions (low pH), at room temperature, and in bacteriomimetic liposomes. In this work, we sought to structurally assign the activated state present in SSNMR experiments. We used a combination of molecular dynamics (MD) simulations, chemical shift prediction algorithms, and Bayesian inference techniques to determine which of the most plausible x-ray structures resolved to date best represents the activated state captured in SSNMR. We first identified specific nuclei with simulated NMR chemical shifts that differed significantly when comparing partially open vs fully open ensembles from MD simulations. The simulated NMR chemical shifts for those specific nuclei were then compared to experimental ones, revealing that the simulation of the partially open state was in good agreement with the SSNMR data. Nuclei that discriminate effectively between partially and fully open states belong to residues spread over the sequence and provide a molecular level description of the conformational change.

Anatomy and Correlation of the Coracoid Process and Coracoclavicular Ligament Based on Three-Dimensional Computed Tomography Reconstruction and Magnetic Resonance Imaging.

BACKGROUND The anatomy of the coracoid process and coracoclavicular (CC) ligament have been described and the correlation between them has been assessed based on 3-dimensional computed tomography (CT) reconstruction and magnetic resonance imaging (MRI), which provide a guide for coracoclavicular ligament reconstruction. MATERIAL AND METHODS Data were collected from 300 patients who underwent both CT and MRI of the shoulder joint from January 2017 to January 2019 at the Jiang'an Hospital of Traditional Chinese Medicine. The coracoid process was observed and classified and parameters of the CC ligament were measured according to different corneal types. All of the statistics were collected and classified by 2 radiologists, and average values were determined.Measurements of segments were taken as follows: ab - In the coronal plane, the length of the CC ligament from the central point of the CC ligament at the clavicular attachment to the CC ligament at the center of the CC attachment); ac - The distance from the center point of the CC ligament at the supraclavicular attachment to the acromioclavicular joint; de - In the sagittal plane, the length of the CC ligament from the center of the clavicular attachment to the coracoid attachment point; fg - The maximum diameter of the CC ligament at the anterior and posterior margins of the clavicle attachment; hi - The largest diameter of the CC ligament at the anterior and posterior edge of the coracoid process attachment; dj - The distance of the coracoclavicular ligament from the center point of the coracoid process attachment to the coracoid process tip; kl - The distance in the supraclavicular plane from the coracoclavicular ligament to the subcoracoid process. RESULTS The analysis showed that there are 5 types of coracoid process: gourd (31%), short rod (20%), long rod (22.3%), wedge (10.3%), and water drop (6.3%). There were statistically significant differences between the lengths of the ac and hi segments in the among the wedge and gourd-type and the short rod and water drop-type coracoid processes. There were statistically significant differences between the lengths of the ab, de, and fg segments in the short rod, gourd, and long rod-type coracoid processes. There were statistically significant differences between the lengths of the ac, fg, hi, dj, and kl segments in the water drop, gourd, and long rod-type coracoid processes. CONCLUSIONS The present study indicated that measurement of the CC ligament and the different shapes of the coracoid process provide an anatomical basis for the diagnosis and treatment of shoulder diseases and the data can be used to improve the safety of CC ligament reconstruction.

Tea consumption and breast cancer risk in a cohort of women with family history of breast cancer.

Laboratory studies have observed chemopreventive effects of black and green tea on breast cancer development, but few epidemiologic studies have identified such effects. We investigated the association between tea consumption and breast cancer risk using data from 45,744 U.S. and Puerto Rican women participating in the Sister Study. Frequency and serving size of black and green tea consumption were measured at cohort enrollment. Breast cancer diagnoses were reported during follow-up and confirmed by medical record review. Multivariable Cox proportional hazards regression was used to estimate hazard ratios (HR) and 95% confidence intervals (CI). We further investigated potential variation according to estrogen receptor (ER) status, menopausal status and body mass index (BMI). Overall, 81.6 and 56.0% of women drank black or green tea, respectively. A total of 2,809 breast cancer cases were identified in the cohort. The multivariable model suggested an inverse association between black (≥5 vs. 0 cups/week: HR = 0.88, 95% CI 0.78, 1.00, p-trend = 0.08) and green tea (≥5 vs. 0 cups/week: HR = 0.82, 95% CI 0.70, 0.95, p-trend < 0.01) consumption and breast cancer risk. We did not observe differences by ER characteristics, menopausal status or BMI. In conclusion, our study suggests drinking at least five cups of green or black tea per week may be associated with decreased breast cancer risk.

Public Understanding of Cigarette Smoke Chemicals: Longitudinal Study of US Adults and Adolescents.

INTRODUCTION: The US Food and Drug Administration has increased communication efforts that aim to raise public awareness of the harmful constituents (ie, chemicals) in cigarette smoke. We sought to investigate whether the public's awareness of these chemicals has increased in light of such efforts. METHODS: Participants were national probability samples of 11 322 US adults and adolescents recruited in 2014-2015 (wave 1) and 2016-2017 (wave 2). Cross-sectional telephone surveys assessed awareness of 24 cigarette smoke chemicals at both timepoints. RESULTS: The proportion of US adults aware of cigarette smoke chemicals did not differ between waves 1 and 2 (25% and 26%, p = .19). In contrast, awareness of chemicals among adolescents fell from 28% to 22% (p < .001), mostly due to lower awareness of carbon monoxide, arsenic, benzene, and four other chemicals. Belief that most of the harmful chemicals in cigarette smoke come from burning the cigarette also fell from waves 1 to 2 (adults: 31% vs. 26%; adolescents: 47% vs. 41%, both ps < .05). Participants were more likely to be aware of cigarette smoke chemicals if they had been exposed to anti-smoking campaign advertisements (p < .05) or had previously sought chemical information (p < .05). Cigarette smoke chemical awareness did not differ between smokers and nonsmokers. CONCLUSION: Awareness of cigarette smoke chemicals remains low and unchanged among adults and decreased somewhat among adolescents. The association of chemical awareness with information exposure via campaigns and information seeking behavior is promising. More concerted communication efforts may be needed to increase public awareness of cigarette smoke chemicals, which could potentially discourage smoking. IMPLICATIONS: Awareness of the toxic chemicals in cigarette smoke may contribute to quitting. The US Food and Drug Administration is making efforts to increase public awareness of these chemicals. Two national surveys (2014-2017) found that chemical awareness was low among adults and adolescents. Although awareness did not change among adults, awareness among adolescents dropped over time. In addition, exposure to anti-smoking campaigns and chemical information seeking behavior were associated with higher awareness of chemicals in cigarette smoke. Campaigns and other efforts may be needed to increase awareness of cigarette smoke chemicals.

Design and Validation of Android Smartphone Based Wireless Structural Vibration Monitoring System.

Vibration monitoring is one of crucial functions of structural health monitoring (SHM) systems. Traditional structural vibration monitoring usually relies on specialized sensors, data transmission and acquisition equipment, which are expensive and may not be easily available in urgently needed situations like post-disaster structural evaluation. Therefore, developing an affordable and efficient structural vibration monitoring technique becomes an important topic in SHM research. In this paper, the authors developed an android system APP that can easily convert multiple android smartphones into a wireless structural vibration monitoring system. To make the designed system reliable and easy to use, the server/client architecture is adopted. One smartphone is designated as the serve of the system to remotely control all other smartphones, which function as sensors to measure structural vibration. An efficient method is proposed herein to establish the smartphone-based structural vibration monitoring network, allowing the server smartphone to quickly and easily connect multiple sensor smartphones to form the wireless network for structural vibration monitoring. Additionally, a synchronization method is also proposed to synchronize different smartphones for simultaneously measuring structural vibration. To verify the time synchronization accuracy of the developed system, an experiment is designed and conducted. Moreover, a new analysis method of the time synchronization accuracy is also proposed, which verifies that the designed smartphone-based monitoring can achieve the millisecond-level time synchronization accuracy. Finally, a shaking table experiment is conducted on a three-story bench-scale structural model, the results of which demonstrate that the designed smartphone-based wireless structural vibration monitoring system can quite accurately identify the modal parameters of the tested structure.

Structural Crack Detection Using DPP-BOTDA and Crack-Induced Features of the Brillouin Gain Spectrum.

Structural damage generally initiates in the form of structural cracks. Thus, developing efficient crack detection techniques is of great importance for the structural health monitoring. In this paper, a new crack identification method is proposed, which is based on the differential pulse-width pair Brillouin optical time domain analysis (DPP-BOTDA) technology and the irregular features of Brillouin gain spectrum (BGS) in the fiber due to structural cracks. The proposed method provides a new way to detect and quantify structural cracks without knowing the strain in the structure. First, the working mechanism of DPP-BOTDA is introduced to illustrate the reason that the DPP-BOTDA, compared to traditional BOTDA technique, can significantly improve the spatial resolution of distributed strain sensing, which is critical for structural crack detection. Then, the BGSs in the fiber with the presence of structural cracks, measured by the DPP-BOTDA, are numerically simulated, from which the crack-induced irregular features of the BGS are summarized. Based these irregular features, new structural crack detection and quantification methods are proposed, which are found to be independent of structural stain. Finally, an experiment is conducted on a simple supported reinforced concrete (RC) beam. The results demonstrate that by using the BGS measured by the DPP-BOTDA, the proposed structural crack identification method successfully detects the occurrence of structural cracks and relatively accurately predicts the crack widths.

A supervised term ranking model for diversity enhanced biomedical information retrieval.

BACKGROUND: The number of biomedical research articles have increased exponentially with the advancement of biomedicine in recent years. These articles have thus brought a great difficulty in obtaining the needed information of researchers. Information retrieval technologies seek to tackle the problem. However, information needs cannot be completely satisfied by directly introducing the existing information retrieval techniques. Therefore, biomedical information retrieval not only focuses on the relevance of search results, but also aims to promote the completeness of the results, which is referred as the diversity-oriented retrieval. RESULTS: We address the diversity-oriented biomedical retrieval task using a supervised term ranking model. The model is learned through a supervised query expansion process for term refinement. Based on the model, the most relevant and diversified terms are selected to enrich the original query. The expanded query is then fed into a second retrieval to improve the relevance and diversity of search results. To this end, we propose three diversity-oriented optimization strategies in our model, including the diversified term labeling strategy, the biomedical resource-based term features and a diversity-oriented group sampling learning method. Experimental results on TREC Genomics collections demonstrate the effectiveness of the proposed model in improving the relevance and the diversity of search results. CONCLUSIONS: The proposed three strategies jointly contribute to the improvement of biomedical retrieval performance. Our model yields more relevant and diversified results than the state-of-the-art baseline models. Moreover, our method provides a general framework for improving biomedical retrieval performance, and can be used as the basis for future work.

Similarities and Differences in Tobacco Control Research Findings From Convenience and Probability Samples.

BACKGROUND: Online convenience samples are a quick and low-cost way to study health behavior, but the comparability to findings from probability samples is not yet well understood. PURPOSE: We sought to compare convenience and probability samples' findings for experiments, correlates, and prevalence in the context of tobacco control research. METHODS: Participants were a probability sample of 5,014 U.S. adults recruited by phone from September 2014 through May 2015 (cost ~U.S.$620,000) and an online convenience sample of 4,137 U.S. adults recruited through Amazon Mechanical Turk (MTurk) in December 2014 (cost ~U.S.$17,000). Participants completed a survey with experiments, measures of tobacco product use and demographic characteristics. RESULTS: MTurk convenience and probability samples showed the same pattern of statistical significance and direction in almost all experiments (21 of 24 analyses did not differ) and observational studies (19 of 25 associations did not differ). Demographic characteristics of the samples differed substantially (1 of 17 estimates did not differ), with the convenience sample being younger, having more years of education, and including more Whites and Asians. Tobacco product use also differed substantially (1 of 22 prevalence estimates did not differ), with the convenience sample reporting more cigarette and e-cigarette use (median error 19%). CONCLUSIONS: Using MTurk convenience samples can yield generalizable findings for experiments and observational studies. Prevalence estimates from MTurk convenience samples are likely to be over- or underestimates.

Tea consumption and oxidative stress: a cross-sectional analysis of 889 premenopausal women from the Sister Study.

In experimental and clinical studies, green or black tea consumption has been shown to reduce oxidative stress. However, these studies involved high levels of tea consumption and may not reflect patterns in the general population. Here, we examined the association between black or green tea consumption and oxidative stress in a cross-sectional study of 889 premenopausal US women aged 35-54 years. Tea consumption was measured using the Block-98 FFQ. Urinary 8-iso-PGF2α (F2-IsoP) and 2,3-dinor-5,6-dihydro-15-F2t-isoprostane (15-F2t-IsoP-M) were used as biomarkers of oxidative stress. These compounds were measured by MS and normalised to creatinine. Linear regression was used to calculate the geometric mean differences (GMD) and 95% CI for log-transformed urinary F2-IsoP or 15-F2t-IsoP-M in relation to black or green tea consumption. We further examined whether adjusting for caffeine impacted associations between tea and oxidative stress. Geometric means of urinary F2-IsoP and 15-F2t-IsoP-M were 1·44 (95% CI 1·39, 1·49) and 0·71 (95% CI 0·69, 0·73) ng/mg creatinine, respectively. Overall, green tea consumption was not associated with urinary F2-IsoP or 15-F2t-IsoP-M. High-level black tea consumption (≥5 cups/week compared with 0) was associated with higher 15-F2t-IsoP-M concentrations (adjusted GMD=0·10, 95 % CI 0·02-0.19) but not F2-IsoP. Adjusting for caffeine nullified the association between black tea and 15-F2t-IsoP-M. Our findings do not support the hypothesis that dietary tea consumption is inversely associated with oxidative stress.