Relative Rate Ratio Research Articles

Depression prevention via digital cognitive behavioral therapy for insomnia: a randomized controlled trial.

Insomnia is a common precursor to depression; yet, the potential for insomnia treatment to prevent depression has not been demonstrated. Cognitive behavioral therapy for insomnia (CBT-I) effectively reduces concurrent symptoms of insomnia and depression and can be delivered digitally (dCBT-I); however, it remains unclear whether treating insomnia leads to sustained reduction and prevention of depression. This randomized controlled trial examined the efficacy of dCBT-I in reducing and preventing depression over a 1-year follow-up period. Patients with Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) insomnia disorder were randomly assigned to receive dCBT-I or an attentional control. The follow-up sample included 358 patients in the dCBT-I condition and 300 patients in the online sleep education condition. The primary outcome measure was relative rate ratios for depression at 1-year follow-up. Insomnia responses to treatment were also tested as predictors of incident depression at the 1-year follow-up. At 1-year follow-up, depression severity continued to be significantly lower in the dCBT-I condition relative to control. In addition, the number of individuals who reported no depression at 1-year follow-up was 51% higher in the dCBT-I condition relative to control. In those with minimal to no depression at baseline, the incident rate of moderate-to-severe depression at 1-year follow-up was reduced by half in the dCBT-I condition relative to the control condition. dCBT-I showed robust effects as an intervention that prevents depression. Future research should examine dose-response requirements and further characterize mechanisms of action of dCBT-I for depression prevention. Sleep to Prevent Evolving Affective Disorders; NCT02988375.

Application of organic acids in Clarias gariepinus Burchell, 1822 aquafeed: impacts on fish relative growth rate, condition factor and cannibalism ratio

The present research was performed to determine the relative growth rate (RGR), condition factor (K) and cannibalism ratio (CR) of Catfish (Clarias gariepinus Burchell, 1822) fed different level and types of organic acid addition in the fish. Eighty fish were randomly assigned into five group triplicates, reared, and fed different type organic acid supplemented viz: control diet with no organic acid addition (B1); mixture of formic, acetic and propionic acid at level 0.05% (B2); mixture of formic, acetic and propionic acid at level 0.1% (B3); 0.05% butyric acid (B4); 0.1% butyric acid (B5), for 8 weeks. At the end of the 8th week, RGR, K, and CR were determined. Fish fed 0.1% mix of formic, acetic and propionic acid or 0.1% butyric acid in the diet had the significantly higher (p<0.05) RGR than control or other groups. Meanwhile, the K and CR of fish during the trial were not affected by any various and levels of the organic acid. In conclusion, the supplementation of 0.1% mix organic acid or 0.1% butyric acid in the diet of C. gariepinus for 8 weeks enhanced the RGR of the catfish but no effect on the condition factor and cannibalism ratio.

Pharmacokinetic and pharmacodynamic modeling of gut hormone peptide YY(3–36) after pulmonary delivery

Peptide YY(3–36) (PYY(3–36)) is an endogenous appetite suppressing peptide. The present research was to perform pharmacokinetic/pharmacodynamic (PK/PD) analysis for predicting the concentration- and response-time profiles of PYY(3–36) after systemic and pulmonary delivery in mice, with the goal of suggesting a potential pulmonary dosing regimen in humans. A PK/PD model was developed to describe PYY(3–36) plasma concentration - and relative food intake rate ratio (as % of control) - time profiles after intraperitoneal and subcutaneous administration, and inhalation in mice. The absorption of inhaled PYY(3–36) from the lungs of mice could only be described with a combined slow (absorption rate of 0.147 L/h) and fast (absorption rate of 104.4 L/h) absorption process, presumably related to absorption from the central and peripheral regions of the lungs. The estimates for IC50 and Imax were 6.8 ng/mL and 63.5%, respectively, based on inhibitory Emax model. The PK parameters, such as clearance (CL), volume of distribution at steady state (Vdss), and the absorption rates (ka), were then scaled to human’s. The scaled human CL and Vdss for obese subjects were 24.8 L/h and 9.0 L, respectively. The model predicted human plasma PYY(3–36) concentrations agreed reasonably well with placebo-normalized plasma PYY(3–36) concentrations after short-term infusion and SC injection in literature. An inhalation dose of PYY(3–36) of about 100 µg was proposed for obese subjects based on simulations. This PK/PD analysis satisfactorily described PYY(3–36) concentration-time and relative food intake rate ratio- time profiles at all doses and routes. The developed model might facilitate the inhalation dose selection of PYY(3–36).

Numerical optimization of design parameters for a modified double-layer microchannel heat sink

In the present work the multi-objective genetic algorithm is employed to optimize the design variables in a double-layer microchannel heat sink. The design matrix is formulated with Latin hypercube sampling and the model approximation is implemented with response surface approximation to reduce the computing time. The design variables for optimization are the relative axial ridge length (Xi) from 0.4 to 1.4, the relative transverse ridge length (Yi) from 0.4 to 0.9, the relative channel length ratio (Li) from 0.2 to 1, and the relative flow rate ratio (σ) from 0.25 to 0.75, respectively. The objective functions are λR (ratio of the thermal resistance of the modified case over base case) and λP (ratio of the total pumping power of the modified case over base case), respectively. The Pareto optimal solutions are extracted and depicted tradeoff between the two objective functions, thus providing a principal understanding into the design variables and allowing autonomy of selection among the optimal solutions. Total 135 Pareto optimal solutions are extracted by using the K-means clustering. Six Pareto optimal combinations (POCs) named as POC – A, POC – B, POC – C, POC – D, POC – E, and POC – F are selected for the comparison of designs. The best design for the heat transfer performance is POC – A (Xi = 0.4003, Yi = 0.4481, Li = 0.6378, σ = 0.2504) with 37.34% lower λR than that for the POC-F, while the best design for the pumping power is POC – F (Xi = 0.4149, Yi = 0.4081, Li = 0.6544, σ = 0.2515) with 96.51% lower λP than that for the POC-A.

Investigation of the effect of tourism on road crashes

The objective of this study is the investigation of the effect of tourism on road crashes. For this purpose, police data on road crashes in Greece for the 5-year period of 2011 to 2015 were collected by the research team and subsequently underwent processing to locate the contributing factors that characterize road crashes, that is, the nationality of the driver, the season, the purpose of traveling and the region, and assign them as independent variables. Negative binomial regression models were developed for this analysis. Application and comparison of the models led to the conclusion that tourists are more often involved in road crashes. More specifically, it was observed that the touristic season and tourism as the purpose of traveling led to an increase in road crashes, with the highest increase being observed in touristic regions. As far as nationality is concerned, the fact that foreign tourists are involved in fewer road crashes than Greek drivers is attributed to the relative risk exposure. However, the increase of the relative rate ratio of road crash involvement for foreign tourists in touristic regions may indicate the increased risk of foreign tourists compared to Greek drivers.

Regional differences and trends in breast cancer surgical procedures and their relation to socioeconomic disparities and screening patterns

BackgroundImportant regional disparities in patterns of care in breast cancer have recently been described. In Switzerland, nationwide data on hospitalisations have been collected since 1998. They have not been used up to now to explore space–time patterns and trends of breast cancer healthcare-related procedures for control and health planning purposes. We aimed to assess geographical and temporal variation of mastectomy rates.MethodsBayesian negative-binomial spatio-temporal models have been applied. Covariates included patient characteristics as provided in the hospital data, data on mammography screening programme duration, and surgeon and gynaecologist density.ResultsWe analyzed more than 70,000 patients. Mastectomy rates declined from 43% to 30% in Switzerland between 2000 and 2012 for patients aged 50–69 and from 61% to 43% for those 70+, and remained stable for those under 50. Important geographical differences in rates were present. Rates were significantly influenced by age [relative rate ratio (RR) 50–69: 0.92, RR 70+: 1.25], differences in co-morbidity (RR one co-morbidity: 1.17, RR more than one: 1.35), higher surgeon or gynaecologist density (RR surgeons: 1.01, RR gynaecologists: 1.06). Regions in the French-speaking part (RR: 0.72) and/or with mammography screening programmes showed significantly lower rates (RR: 0.87). No difference was found for patients in different socio-economic groups or with different insurance types.ConclusionThis research unveiled important differences in mastectomy rates in Switzerland. The results play an essential role in the identification of regions where special attention is required, and indications for extensive surgery in breast cancer should be revisited.

Gastrointestinal safety of coxibs: systematic review and meta-analysis of observational studies on selective inhibitors of cyclo-oxygenase 2.

Prior meta-analyses have shown a higher gastrointestinal risk of nonselective NSAIDs versus placebo and a lower gastrointestinal risk of coxibs versus nonselective NSAIDs. However, the available data about gastrointestinal risk for coxibs versus placebo are scarce. The aim of this study was to review the current evidence on the use of coxibs and to evaluate the risk of gastrointestinal adverse outcomes (GAO) associated with coxibs versus nonexposed. Search was conducted on PubMed and Embase databases. We selected cohort observational, case-control, nested case-control and case-crossover studies that reported the risk of GAO associated with coxibs versus nonexposed as relative risk (RR), odds ratio (OR), hazard ratio (HR) or incidence rate ratio (IRR). It was estimated the pooled RR and the 95% confidence interval (CI) for coxibs both individually and as a whole by the DerSimonian and Laird method. Twenty-eight studies met inclusion criteria. Overall, coxibs were associated with a significant increment in the risk of GAO [RR 1.64 (95% CI 1.44-1.86)]. The analysis by individual drugs showed that etoricoxib [RR 4.85 (95% CI 2.64-8.93)] presented the highest gastrointestinal risk, followed by rofecoxib [RR 2.02 (95% CI 1.56-2.61)] and celecoxib [RR 1.53 (95% CI 1.19-1.97)]. Gastrointestinal risk was also high for the subgroups aged <65years and low-dose coxibs. The use of coxibs is associated with a statistically significant increased risk of GAO, which would be high even for low-dose coxibs and <65-year-old subgroups. The risk would be higher for etoricoxib than for celecoxib and rofecoxib.

Effect of organized mammography screening on breast cancer mortality: A population‐based cohort study in Norway

We aimed to estimate the effect of organized mammography screening on incidence-based breast cancer mortality by comparing changes in mortality among women eligible for screening to concurrent changes in younger and older ineligible women. In a county-wise balanced, open-cohort study, we used birth cohorts (1896-1982) to construct three age groups in both the historical and screening period: women eligible for screening, and younger or older women ineligible for screening. We included women diagnosed with breast cancer who died within the same age-period group during 1987-2010 (n = 4,903). We estimated relative incidence-based mortality rate ratios (relative MRR) comparing temporal changes in eligible women to concurrent changes in ineligible women. Additionally, we conducted analyses comparing the change in eligible women to younger, ineligible women with either continued accrual and follow-up period (eligible women only) or continued follow-up period. All three age groups experienced a reduction in mortality, but the decrease among eligible women was about the same among ineligible women (relative MRR = 1.05, 95% CI: (0.94-1.18)). Varying the definition of follow-up yielded similar results. Mammography screening was not associated with a larger breast cancer mortality reduction in women eligible relative to ineligible women.

Cost reduction associated with heparin-induced thrombocytopenia panel ordering for enoxaparin versus heparin for prophylactic and therapeutic use: A retrospective analysis in a community hospital setting.

Background:Most hospitals still use unfractionated heparin (UFH) as the primary agent for venous thromboembolism (VTE) prophylaxis in the hospital setting due to ease of use and insignificant cost. However, the risk of heparin-induced thrombocytopenia (HIT) has led some groups to favor other options for therapeutic and prophylactic anticoagulation. This is particularly relevant in light of recent data demonstrating a lower rate of HIT in patients receiving enoxaparin compared with UFH. This study examines the cost-effectiveness of enoxaparin, compared to UFH for prophylactic and therapeutic usage in hospitals.Methods:We conducted a retrospective chart review of patients who underwent HIT panel testing at the Inspira Health Network, Vineland campus (an approximately 262-bedded community hospital located in southern New Jersey that services a population of approximately 61,050) from the period of April 1, 2015 through December 31, 2016. The starting date represents the time from which enoxaparin became the primary alternative anticoagulant available at this hospital. Records of the total usage and cost of UFH and enoxaparin for the specified time period were collected from the hospital pharmacy database for evaluation, as were records of HIT panels. The information was analyzed to determine the frequency of HIT panel testing orders for patients receiving UFH versus those receiving enoxaparin. Annual cost-savings for the hospital were extrapolated using the comparative incidence of HIT panels and associated costs, including increased length of stay, hematology/oncology consultation, use of an alternative anticoagulant, critical bleeding requiring transfusion, and complications of HIT-associated thrombosis. These variables were multiplied by the incidence rate for each specified drug and usage to determine the daily cost for each drug.Results:The use of enoxaparin did not result in a significant decrease in the ordering of HIT panels in the hospital, with a relative rate ratio of 0.948 (95% confidence interval: 0.336, 2.21). When the data were stratified to examine prophylactic and therapeutic anticoagulation, there was a marked difference in the frequency of HIT testing. The rate ratio of HIT panel orders for patients receiving therapeutic enoxaparin rather than intravenous (IV) UFH was 0.118 (0.006, 0.625). These numbers were used to extrapolate the total daily cost of enoxaparin compared with IV UFH; therapeutic enoxaparin cost $30.66, while IV UFH cost $162.30. IV UFH use was associated with a higher incidence rate of HIT panel orders, and consequently a higher daily cost due to the likelihood of increased length of stay, use of alternative anticoagulation, bleeding requiring transfusion, and request for expert consultation.Conclusion:In this study, the use of enoxaparin was associated with a significant cost-saving over IV UFH when used for therapeutic anticoagulation, but this cost saving was not observed for prophylactic anticoagulation.

Cardiovascular Risk of Nonsteroidal Anti-inflammatory Drugs and Classical and Selective Cyclooxygenase-2 Inhibitors: A Meta-analysis of Observational Studies.

The purpose of this study was to review the published evidence on the clinical use of nonsteroidal anti-inflammatory drugs (NSAIDs) and to assess the cardiovascular risk (CVR) of cyclooxygenase-2 inhibitors (coxibs), excluding aspirin, by means of a meta-analytic procedure. A search was conducted on MEDLINE and EMBASE databases between October 1999 and June 2018. Cohort and case-control studies showing CVR as relative risk (RR), odds ratio, hazard ratio, or incidence rate ratio associated with NSAIDs versus no treatment were selected. We estimated the pooled RR and the 95% confidence interval (CI) for all NSAIDs as a whole and individually. Eighty-seven studies met the inclusion criteria. Overall, NSAIDs were found to be associated with a statistically significantly increased CVR (RR, 1.24 [95%CI, 1.19-1.28]). The risk was slightly higher for coxibs (RR, 1.22 [95%CI, 1.17-1.28]) as compared with nonselective NSAIDs (RR, 1.18 [95%CI, 1.12-1.24]). Data analysis by drug disclosed that rofecoxib (RR, 1.39 [95%CI, 1.31-1.47]), followed by diclofenac (RR, 1.34 [95%CI, 1.26-1.42]) and etoricoxib (RR, 1.27 [95%CI, 1.12-1.43]) were the NSAIDs associated with the highest CVR. Analysis by type of event showed that the highest risk corresponded to vascular events for both coxibs (RR, 2.18 [95%CI, 1.72-2.78]) and nonselective NSAIDs (RR, 2.46 [95%CI, 2.00-3.02]). The meta-analysis results suggest that the use of the marketed coxibs celecoxib and etoricoxib would be related to a statistically significant CVR increase. Etoricoxib CVR could be higher than that for celecoxib. This increment would be similar to classical NSAID CVR.

A comprehensive first-principles study of solute elements in dilute Ni alloys: Diffusion coefficients and their implications to tailor creep rate

Diffusion regulates a vast number of materials properties and phenomena such as creep, the focus of the present work. However, a deep understanding of the effect of how each alloying element in a Ni-base superalloy affects properties such as diffusion and creep is far from complete. Here, we report temperature-dependent dilute solute diffusion coefficients and their implications to tailor the creep rate for 26 transition metal solute elements, X's, in fcc Ni using first-principles calculations. Calculations are performed using the five-frequency model for dilute solute diffusion and the nudged elastic band method within the local density approximation. Thermodynamic properties at finite temperatures for all configurations are calculated using the quasi-harmonic Debye model. In general, the fastest diffusing solute elements in Ni are found at the left side of the periodic table and the slowest diffusing solute elements are found in group VIIB. In particular, the present work indicates that the diffusivity of the dilute solute elements is correlated to the compressibility of each solute element on the respective Ni31X supercell, and not as strongly to the ionic radius of the solute elements, as previously suggested. Finally, results from the diffusivity study are combined with the previous results of elastic constants and stacking fault energies, and hence, a relative creep rate ratio for these 26 solute elements is modeled. It is shown that in most cases, slower diffusing solute elements provide the most creep resistance. This is true even at higher temperatures, due mainly to the solute's strong bonding with Ni atoms in the host lattice.

Effect of organized mammography screening on breast cancer mortality: a population-based cohort study in Norway

Background Reviews of the randomized controlled trials (RCTs) of mammography screening conducted during the 1970s and 1980s reported a 15–21% reduction in breast cancer mortality. Improved cancer treatment and enhanced awareness may however have reduced the potential net benefit from mammography screening. New RCTs are no longer feasible and observational studies yield widely varying estimates of the reduced breast cancer mortality (0% to 43%), depending on study design. In Norway, mammography screening was introduced gradually during the period 1996–2004. Using this as a natural experiment, we aimed to estimate the effect of organized mammography screening on incidence-based breast cancer mortality by comparing changes in mortality among women eligible for screening to concurrent changes in younger and older ineligible women. The use of un-screened age-groups as control groups allowed us to conduct a balanced incidence-based mortality study in which we aimed to distinguish the screening effect on breast cancer mortality from the effect of the concomitantly established diagnostic centers, which may also have improved treatment. Methods In a national county-wise balanced, open-cohort study in Norway, we used birth cohorts (1896–1982) to construct three age groups in both the historical and screening period: women eligible for screening and younger or older women ineligible for screening. We included women diagnosed with breast cancer who died within the same age-period group during 1987–2010 (n = 4903). We estimated relative incidence-based mortality rate ratios (relative MRR) comparing temporal changes in eligible women to concurrent changes in ineligible women. Additionally, we conducted analyses comparing the change in eligible women to younger, ineligible women with either continued accrual and follow-up period (eligible women only) or continued follow-up period. Finally, we checked for unadjusted confounding in two negative control analyses expected to produce a null result (relative MRR = 1). First, we compared the mortality change in younger women to the concurrent change in older women. Second, we extended the study period to include the period 1987–2010 for all counties and repeated our analysis as if screening had been introduced at the midpoint of the actual pre-screening period and the actual screening period in each county, respectively. Results All three age groups experienced a reduction in mortality when screening was introduced, but the decrease among eligible women was about the same among ineligible women (relative MRR = 1.05, 95% CI: [0.94–1.18]). Varying the definition of follow-up yields similar results. The negative control analyses all had relative MRRs close to 1 (estimates ranged from 0.91 to 1.04 and with all 95% CIs overlapping 1). Conclusion Mammography screening was not associated with a larger breast cancer mortality reduction than that of women ineligible for mammography screening. Based on the negative control analyses we found limited uncontrolled confounding in the applied observational design.

EXSCEL—Once-Weekly Exenatide Reduces Medical Resource Utilization in Patients with Type 2 Diabetes Mellitus

Objectives: To evaluate the effect of exenatide 2mg once-weekly vs. placebo in addition to usual care on medical resource use among 14,572 patients with type 2 diabetes enrolled in the Exenatide Study of Cardiovascular Event Lowering (EXSCEL), which demonstrated a statistically non-significant reduction in major adverse cardiovascular events and a nominally significant reduction in all-cause mortality with exenatide once-weekly administration. Methods: Data on medical resource use were collected from randomization to study end. Hierarchical generalized linear models were used to compare medical resource use between groups, with an offset to account for patient-level of follow-up duration. Random intercepts modeled country-specific variations in resource use and a fixed effect modeled the relative impact of exenatide vs. placebo. Results: Mean follow-up was 3.3 years in both groups. The mean number of hospitalizations was similar between the two groups (0.83 in the exenatide group vs. 0.84 in the placebo group; p=0.31), as were annual hospitalization rates, ranging from 0.24-0.29 per person-year from Year 1 to Year 5. The mean cumulative number of inpatient days over the trial follow-up period was 0.41 days lower in the exenatide group than in the placebo group (7.days vs. 7.46 days, respectively; relative rate ratio: 0.910; p=0.048). Patients treated with exenatide had an average of 8.88 outpatient visits to usual diabetes care providers compared to 9.14 for patients treated with placebo (p=0.048). Outpatient visits to other healthcare providers were similar at 12.19 for the exenatide group vs. 11.78 for the placebo group (p=0.80). Country-level variations in resource use were significant. Conclusions: Type 2 diabetes patients treated with exenatide in addition to usual care incurred significant reductions in inpatient hospital days and outpatient visits to their diabetes care providers compared to patients treated with placebo in addition to usual care. Disclosure S.D. Reed: Research Support; Self; AstraZeneca, Merck &amp; Co., Inc.. Y. Li: None. H.A. Dakin: Research Support; Self; AstraZeneca, Pfizer Inc.. F. Becker: None. J. Leal: None. S. Gustavson: Employee; Self; AstraZeneca. Employee; Spouse/Partner; AstraZeneca. B. Kartman: Employee; Self; AstraZeneca. E.T. Wittbrodt: Employee; Self; AstraZeneca. R.J. Mentz: Research Support; Self; AstraZeneca, GlaxoSmithKline plc., Merck &amp; Co., Inc. N. Pagidipati: Research Support; Self; AstraZeneca, Novartis Pharmaceuticals Corporation, Sanofi, Amgen Inc., Novo Nordisk Inc., Intarcia Therapeutics, Inc. M. Bethel: Research Support; Self; AstraZeneca, Merck Sharp &amp; Dohme Corp., Merck Serono. Advisory Panel; Self; Boehringer Ingelheim Pharmaceuticals, Inc.. Consultant; Self; Novo Nordisk Inc.. Advisory Panel; Self; AstraZeneca. Other Relationship; Self; Sanofi. Consultant; Self; Theracos, Inc.. Research Support; Self; GlaxoSmithKline plc. A.M. Gray: Advisory Panel; Self; Novo Nordisk A/S. Speaker's Bureau; Self; Novartis AG. R.R. Holman: Research Support; Self; AstraZeneca, Merck &amp; Co., Inc., Bayer AG. Advisory Panel; Self; Elcelyx Therapeutics, Inc., Novartis AG, Novo Nordisk A/S. Other Relationship; Self; Bayer AG. Advisory Panel; Self; Merck &amp; Co., Inc.. Other Relationship; Self; AstraZeneca. A.F. Hernandez: Research Support; Self; AstraZeneca, GlaxoSmithKline plc., Merck &amp; Co., Inc.. Consultant; Self; Bayer AG, Boehringer Ingelheim Pharmaceuticals, Inc.. Research Support; Self; Janssen Pharmaceuticals, Inc., Novartis Pharmaceuticals Corporation.

Gas‐phase rate coefficients for a series of alkyl cyclohexanes with OH radicals and Cl atoms

AbstractThe rate coefficients of the reactions of OH radicals and Cl atoms with three alkylcyclohexanes compounds, methylcyclohexane (MCH), trans‐1,4‐dimethylcyclohexane (DCH), and ethylcyclohexane (ECH) have been investigated at (293 ± 1) K and 1000 mbar of air using relative rate methods. A majority of the experiments were performed in the Highly Instrumented Reactor for Atmospheric Chemistry (HIRAC), a stainless steel chamber using in situ FTIR analysis and online gas chromatography with flame ionization detection (GC‐FID) detection to monitor the decay of the alkylcyclohexanes and the reference compounds. The studies were undertaken to provide kinetic data for calibrations of radical detection techniques in HIRAC. The following rate coefficients (in cm3 molecule−1 s−1) were obtained for Cl reactions: k(Cl+MCH) = (3.51 ± 0.37) × 10–10, k(Cl+DCH) = (3.63 ± 0.38) × 10−10, k(Cl+ECH) = (3.88 ± 0.41) × 10−10, and for the reactions with OH radicals: k(OH+MCH) = (9.5 ± 1.3) × 10–12, k(OH+DCH) = (12.1 ± 2.2) × 10−12, k(OH+ECH) = (11.8 ± 2.0) × 10−12. Errors are a combination of statistical errors in the relative rate ratio (2σ) and the error in the reference rate coefficient. Checks for possible systematic errors were made by the use of two reference compounds, two different measurement techniques, and also three different sources of OH were employed in this study: photolysis of CH3ONO with black lamps, photolysis of H2O2 at 254 nm, and nonphotolytic trans‐2‐butene ozonolysis. For DCH, some direct laser flash photolysis studies were also undertaken, producing results in good agreement with the relative rate measurements. Additionally, temperature‐dependent rate coefficient investigations were performed for the reaction of methylcyclohexane with the OH radical over the range 273‐343 K using the relative rate method; the resulting recommended Arrhenius expression is k(OH + MCH) = (1.85 ± 0.27) × 10–11 exp((–1.62 ± 0.16) kJ mol−1/RT) cm3 molecule−1 s−1. The kinetic data are discussed in terms of OH and Cl reactivity trends, and comparisons are made with the existing literature values and with rate coefficients from structure‐activity relationship methods. This is the first study on the rate coefficient determination of the reaction of ECH with OH radicals and chlorine atoms, respectively.

Generation of Linear and Parabolic Concentration Gradients by Using a Christmas Tree-Shaped Microfluidic Network

This paper describes a simple method of generating concentration gradients with linear and parabolic profiles by using a Christmas tree-shaped microfluidic network. The microfluidic gradient generator consists of two parts: a Christmas tree-shaped network for gradient generation and a broad microchannel for detection. A two-dimensional model was built to analyze the flow field and the mass transfer in the microfluidic network. The simulating results show that a series of linear and parabolic gradient profiles were generated via adjusting relative flow rate ratios of the two source solutions (RL2 ≥0.995 and RP2 ≥0.999), which could match well with the experimental results (RL2 ≥0.987 and RP2 ≥0.996). The proposed method is promising for the generation of linear and parabolic concentration gradient profiles, with the potential in chemical and biological applications such as combinatorial chemistry synthesis, stem cell differentiation or cytotoxicity assays.

Behavioral Responses of Nile Tilapia (Oreochromis niloticus) to Feed Restriction Regime

Food restriction and re-feeding regime can be used as a management tool to reduce feeding cost. The present study was carried out to investigate behavioral adaptation of Nile tilapia to food restriction regime. Fish (n=40) were classified into two groups (n=20/group, 2 replicates). Experimental period was divided into two parts. The first part lasted for 8 weeks while the second part was fulfilled to 11th weeks. The first group (control) fed daily throughout experimental periods. The second group (restricted), fish were restricted of food two days per week during the first part, and then re-fed as control in the second part. Behavior of fish, body weight, body dimensions and water quality were recorded. Weight gain, relative growth rate and feed conversion ratio were calculated. The results demonstrated that food restriction significantly increased resting, schooling and chafing behaviors, but decreased eliminative, chasing and mouth pushing behaviors. Food restriction significantly reduced body weight. However, the relative growth rate and feed conversion ratio were improved in restricted fish than control one. Water quality parameters were improved with increased dissolved oxygen and maintenance pH in restricted fish. It was concluded that Tilapia were adapted behaviorally to food restriction regime by increasing comfort behavior and reducing aggressive behavior that indicate adjustment capability of Tilapia to food deprivation.

Estimates of (co)variance components and genetic parameters for body weights and growth efficiency traits in the New Zealand white rabbit

The genetic parameters of growth traits in the New Zealand White rabbits kept at Sheep Breeding and Research Station, Sandynallah, The Nilgiris, India were estimated by partitioning the variance and covariance components. The (co)variance components of body weights at weaning (W42), post-weaning (W70) and marketing (W135) age and growth efficiency traits viz., average daily gain (ADG), relative growth rate (RGR) and Kleiber ratio (KR) estimated on a daily basis at different age intervals (42 to 70 d; 70 to 135 d and 42 to 135 d) from weaning to marketing were estimated by restricted maximum likelihood, fitting 6 animal models with various combinations of direct and maternal effects. Data were collected over a period of 15 yr (1998 to 2012). A log-likelihood ratio test was used to select the most appropriate univariate model for each trait, which was subsequently used in bivariate analysis. Heritability estimates for W42, W70 and W135 were 0.42±0.07, 0.40±0.08 and 0.27±0.07, respectively. Heritability estimates of growth efficiency traits were moderate to high (0.18 to 0.42). Of the total phenotypic variation, maternal genetic effect contributed 14 to 32% for early body weight traits (W42 and W70) and ADG1. The contribution of maternal permanent environmental effect varied from 6 to 18% for W42 and for all the growth efficiency traits except for KR2. Maternal permanent environmental effect on most of the growth efficiency traits was a carryover effect of maternal care during weaning. Direct maternal genetic correlations, for the traits in which maternal genetic effect was significant, were moderate to high in magnitude and negative in direction. Maternal effect declined as the age of the animal increased. The estimates of total heritability and maternal across year repeatability for growth traits were moderate and an optimum rate of genetic progress seems possible in the herd by mass selection. The genetic and phenotypic correlations among body weights and between growth efficiency traits were also estimated. Moderate to high heritability and higher genetic correlation in body weight traits promise good scope for genetic improvement provided measures are taken to keep the inbreeding at the lowest level.

Antibiotic Exposure and Risk of Community-associated Clostridium difficile infection (CA-CDI): A Self-Controlled Case Series Analysis

BackgroundCA-CDI accounts for up to 50% of all CDIs. Case–control studies (CCS) have been used to estimate the odds ratio (OR) of CA-CDI associated with antibiotic exposure. These ORs demonstrate significant heterogeneity across studies. Unlike CCS, a self-controlled case series (SCCS) design can be used to control for all time-invariant confounders leading to less biased effect estimates.MethodsAdults (≥18 years) registered (N = 139,670) with the Barrie and Community Family Health Team (BCFHT) were included in the study. Cases were defined as any patient with an incident case of CA-CDI and ≥1 antibiotic exposure occurring between January 1, 2011 and December 31, 2016. The SCCS model was used to estimate the association between antibiotic exposure and CA-CDI. The SCCS model yields estimates of the relative incidence rate of CA-CDI in exposure periods relative to non-exposure periods within a case. Exposure periods were defined as starting two days after any antibiotic prescription and ending 60 days later. Multiple exposure periods and time-varying confounders due to calendar year were included in the final model. The relative incidence rate ratio (IRR) was estimated using conditional poisson regression analysis. Proton pump inhibitor (PPI) use was included as an effect modifier. Antibiotics were divided into high-risk (fluoroquinolone, clindamycin, and cephalosporin) and low-risk exposures. Research ethics approval was obtained from the BFCHT research ethics board.ResultsAmong 544 total CDI cases, N = 189 CA-CDI cases met the inclusion criteria. Any antibiotic exposure increases the risk by ≥2-fold, with no difference observed between high and low-risk groups (IRR=1.11, 95% CI 0.53–2.36) (Table 1).ConclusionAntibiotic exposure increases the risk of CA-CDI, with IRR estimates similar to those observed for healthcare-associated-CDI. This, along with the control of all time-invariant confounders by the SCCS method suggests a less biased effect estimate previously reported from CCS.Table 1 Variable IRR 95% Confidence Interval P-value Antibiotic Exposure GroupPPINoneYes0.80(0.62–1.03)0.09Low riskYes1.95(0.09–4.24)0.09High riskYes1.20(0.42–3.40)0.73OverallLow risk2.03(1.19–3.47)0.009High risk2.26(1.29–3.98)0.005Disclosures All authors: No reported disclosures.

Trends in educational inequalities in obesity in 15 European countries between 1990 and 2010

BackgroundThe prevalence of obesity increased dramatically in many European countries in the past decades. Whether the increase occurred to the same extent in all socioeconomic groups is less known. We systematically assessed and compared the trends in educational inequalities in obesity in 15 different European countries between 1990 and 2010.MethodsNationally representative survey data from 15 European countries were harmonized and used in a meta-regression of trends in prevalence and educational inequalities in obesity between 1990 and 2010. Educational inequalities were estimated by means of absolute rate differences and relative rate ratios in men and women aged 30–64 years.ResultsA statistically significant increase in the prevalence of obesity was found for all countries, except for Ireland (among men) and for France, Hungary, Italy and Poland (among women). Meta-regressions showed a statistically significant overall increase in absolute inequalities of 0.11% points [95% CI 0.03, 0.20] per year among men and 0.12% points [95% CI 0.04, 0.20] per year among women. Relative inequalities did not significantly change over time in most countries. A significant reduction of relative inequalities was found among Austrian and Italian women.ConclusionThe increase in the overall prevalence aligned with a widening of absolute but not of relative inequalities in obesity in many European countries over the past two decades. Our findings urge for a further understanding of the drivers of the increase in obesity in lower education groups particularly, and an equity perspective in population-based obesity prevention strategies.

Estimate of mortality reduction with implementation of advanced automatic collision notification

ABSTRACTObjective: Advanced Automatic Collision Notification (AACN) is a system on a motor vehicle that notifies a public safety answering point (PSAP), either directly or through a third party, that the vehicle has had a crash. AACN systems enable earlier notification of a motor vehicle crash and provide an injury prediction that can help dispatchers and first responders make better decisions about how and where to transport the patient, thus getting the patient to definitive care sooner. The purposes of the current research are to identify the target population that could benefit from AACN, and to develop a reasonable estimate range of potential lives saved with implementation of AACN within the vehicle fleet.Methods: Data from the Fatality Analysis Reporting System (FARS) years 2009–2015 and National Automotive Sampling System–Crashworthiness Data System (NASS-CDS) years 2000–2015 were obtained. FARS data were used to determine absolute estimates of the target population who may receive benefit from AACN. These estimates accounted for a number of factors, such as whether a fatal occupant had nearby access to a trauma center and also was correctly identified by the injury severity prediction algorithm as having a “high probability of severe injury.” NASS-CDS data were used to provide relative comparisons among subsets of the population. Specifically, relative survival rate ratios between occupants treated at trauma centers versus at non-trauma centers were determined using the nonparametric Kaplan–Meier estimator. Finally, the fatality reduction rate associated with trauma center care was combined with the previously published fatality reduction rate for faster notification time to develop a range for possible lives saved.Results: Two relevant target populations were identified. A larger subset of 6893 fatalities can benefit only from earlier notification associated with AACN. A smaller subgroup of between 1495 and 2330 fatalities can benefit from both earlier notification and change in treatment destination (i.e., non-trauma center to trauma center). A Kaplan–Meier life curve and a multiple proportional hazard model were used to predict the benefits associated with transport to a trauma center. The resulting range for potential lives saved annually was 360 to 721.Conclusions: This analysis provides the estimates of lives that could potentially be saved with full implementation of AACN and universal cell coverage availability. This represents a fatality reduction of approximately 1.6% to 3.3% per year, and more than double the lives saved by earlier notification alone. In conclusion, AACN is a postcrash technology with a promising potential for safety benefit. AACN is therefore a key component of integrated safety systems that aim to protect occupants across the entire crash spectrum.