SciCombinator

Discover the most talked about and latest scientific content & concepts.

Concept: Segment

169

Segments of identity by descent (IBD) detected from high-density genetic data are useful for many applications, including long-range phase determination, phasing family data, imputation, IBD mapping and heritability analysis in founder populations. We present Refined IBD, a new method for IBD segment detection. Refined IBD achieves both computational efficiency and highly accurate IBD segment reporting by searching for IBD in two steps. The first step (identification) uses the GERMLINE algorithm to find shared haplotypes exceeding a length threshold. The second step (refinement), evaluates candidate segments with a probabilistic approach to assess the evidence for IBD. Like GERMLINE, Refined IBD allows for IBD reporting on a haplotype level, which facilitates determination of multi-individual IBD and allows for haplotype-based downstream analyses. To investigate the properties of Refined IBD, we simulate SNP data from a model with recent super-exponential population growth that is designed to match UK data. The simulation results show that Refined IBD achieves a better power/accuracy profile than fastIBD or GERMLINE. We find that a single run of Refined IBD achieves greater power than 10 runs of fastIBD. We also apply Refined IBD to SNP data for samples from the UK and from Northern Finland, and describe the IBD sharing in these data sets. Refined IBD is powerful, highly accurate, easy to use, and is implemented in Beagle version 4.

Concepts: Accuracy and precision, Segment, Demography, Carrying capacity, World population, Population ecology, Genetics, Population

150

Vaccine exposure to temperatures below recommended ranges in the cold chain may decrease vaccine potency of freeze-sensitive vaccines leading to a loss of vaccine investments and potentially places children at risk of contracting vaccine preventable illnesses. This literature review is an update to one previously published in 2007 (Matthias et al., 2007), analyzing the prevalence of vaccine exposure to temperatures below recommendations throughout various segments of the cold chain. Overall, 45 studies included in this review assess temperature monitoring, of which 29 specifically assess ‘too cold’ temperatures. The storage segments alone were evaluated in 41 articles, 15 articles examined the transport segment and 4 studied outreach sessions. The sample size of the studies varied, ranging from one to 103 shipments and from three to 440 storage units. Among reviewed articles, the percentage of vaccine exposure to temperatures below recommended ranges during storage was 33% in wealthier countries and 37.1% in lower income countries. Vaccine exposure to temperatures below recommended ranges occurred during shipments in 38% of studies from higher income countries and 19.3% in lower income countries. This review highlights continuing issues of vaccine exposure to temperatures below recommended ranges during various segments of the cold chain. Studies monitoring the number of events vaccines are exposed to ‘too cold’ temperatures as well as the duration of these events are needed. Many reviewed studies emphasize the lack of knowledge of health workers regarding freeze damage of vaccines and how this has an effect on temperature monitoring. It is important to address this issue by educating vaccinators and cold chain staff to improve temperature maintenance and supply chain management, which will facilitate the distribution of potent vaccines to children.

Concepts: Segment, Influenza, Cold, Logistics, Supply chain, Temperature, Vaccine, Supply chain management

28

This study examined the mechanomyographic (MMGRMS) amplitude-force relationships for 5 (age = 19.20 ± 0.45 years) aerobically trained (AT), 5 (age = 25 ± 4.53 years) resistance-trained (RT) and 5 (age = 21.20 ± 2.17 years) sedentary (SED) individuals. Participants performed an isometric trapezoidal muscle action at 60% maximal voluntary contraction of the leg extensors that included linearly increasing, steady force, and linearly decreasing muscle actions. MMG and skinfold thickness were recorded from the vastus lateralis. b and a terms were calculated from the natural log-transformed MMGRMS-force relationships (linearly increasing and decreasing segments) for each participant. An average of MMGRMS was calculated for the entire steady force segment. The b terms for the RT (0.727 ± 0.334) and SED (0.622 ± 0.281) were significantly greater (P < 0.05) than the AT (0.159 ± 0.223) and were greater during the linearly increasing (0.622 ± 0.426) than decreasing (0.383 ± 0.269) segments when collapsed across segments and training status, respectively. MMGRMS during the steady force segment and skinfold thicknesses were not different among training statuses (P = 0.106, P = 0.142). Motor unit (MU) activation strategies were influenced as a function of exercise training status and muscle action. Future research is needed to fully understand the implications of these changes in MU control strategies as a result of chronic exercise training on exercise and athletic performance.

Concepts: Segment, Convex function, Monotonic function, Muscle contraction, Order theory, Vastus lateralis muscle, Adipose tissue, Function

28

Previous electromyographic (EMG) studies of gluteus medius (GMed) have not accurately quantified the function of the three proposed structurally and functionally unique segments (anterior, middle and posterior). Therefore this study used anatomically verified locations for intramuscular electrode recordings in three segments of GMed to determine whether the segments are functionally independent. Bipolar fine wire electrodes were inserted into each segment of GMed in 15 healthy individuals. Participants completed a series of four walking trials, followed by maximum voluntary isometric contractions (MVICs) in five different positions. Temporal and amplitude variables for each segment were compared across the gait cycle using ANOVA. The relative contributions of each segment to the MVIC trials were compared with non-parametric tests. All segments showed a biphasic response during the stance phase of gait. There were no differences in amplitude variables (% MVIC) between segments, but the anterior segment had a later peak during both the first and second bursts.For the MVIC trials, there were significant differences in amplitude between segments in four of the five test positions. These data indicate that GMed is composed of three functionally independent segments. This study contributes to the theoretical understanding of the role of GMed.

Concepts: Gluteal muscles, Electromyography, Electroencephalography, Isometric exercise, Non-parametric statistics, Electrode, Segment, Gluteus medius muscle

28

Little is known about the influence of speed-endurance workouts on the improvement of pacing strategies in the 800-m running event. This study aims to analyze it, comparing continuous repetitions vs. interval training workouts. Since we hypothesize that pacing is susceptible to expertise, there might be age-differences. 19 male 800-m runners (age: 21.36±5.26, Season-Best [SB]: 117.14±5.18 s) were tested. Athletes were asked to run 1x600 m (6r) at 100%[SB] and 2x4(200m/30s)/15min (B8) at 102%[SB], counterbalanced and randomized within one week of difference. Pacing strategy (velocity dynamics) was analyzed by means of time differences in 200-m segments (T200), while age-category was considered a grouping factor (Under-Senior, n=10; vs. Juvenile-Junior, n=9; 25.29±4.32, 17.00±0.66 years). Blood lactate was registered after 6r, B81 & B82 bouts. Univariate contrast analysis revealed a significant decrease in velocity during 6r (p<0.001; 9.33% between 1 and 3 segment), thus a Positive Pacing, whatever the age-category. B8 shared this final significant impairment (p<0.001), although it was smaller (5.73% drop for B81; 8.47% for B82), and neither linear nor significant among consecutive T200. B8 also showed significant differences (p<0.05) in the interaction sampling condition*age-category. T-test added blood lactate significant differences (B82: 15.42±1.16, B81: 12.25±2.03 & 6r: 13.58±1.82 mmol/L). Summarizing, both methods share a positive pacing, confirming to be related to enhancing energy systems and coping final fatigue in the 800-m. Continuous 6r preserves the nature and tempo of the 800-m, although one repetition is metabolically limited. Interval B8 allows larger amounts of high intensity running, enhancing neuromuscular benefits jointly with higher lactate productions. Significant age-category differences in B8 indicate that pacing capacity may improve with expertise, and interval workouts may be appropriate methods to manage it.

Concepts: Better, Dean Koontz, Segment, Repetition, Interval training, High-intensity interval training, Running

27

STUDY DESIGN:: Retrospectively study. OBJECTIVES:: To evaluate clinical and radiological outcomes of skip-level anterior cervical discectomy and fusion (ACDF) with self-locking stand-alone polyetheretherketone (PEEK) cages for the treatment of two noncontiguous levels of cervical disc degenerative disease (CDDD). SUMMARY OF BACKGROUND DATA:: The use of stand-alone PEEK cages in ACDF has been proved to be safe and effective to treat CDDD. For two noncontiguous levels of CDDD, skip-level ACDF with self-locking stand-alone PEEK cages, which fuses only the involved levels without anterior plates, may be the optimal treatment choice. METHODS:: Sixteen consecutive patients with two noncontiguous levels of CDDD underwent skip-level ACDF with self-locking stand-alone PEEK cages. Clinical outcomes were evaluated using Japanese Orthopaedic Association (JOA) scores and Odom’s criteria. Fusion rate and time, cages subsidence, spinal curvature, intervertebral height at the operated level, and adjacent disc degeneration were assessed. RESULTS:: Patients were followed up for average 43.6 months (range 24-78 mo). The mean operative time was 113 minutes (range 98-134 min) with an average blood loss of 62 mL (range 47-76 mL). The JOA score, degree of spinal curvature, and intervertebral height were significantly increased at the final follow-up examination compared with preoperatively (P<0.05). Fifteen patients (93.8%) achieved solid fusion in an average time of 5.1 months. Three cages (9.38%) in two patients subsided. Radiological evidence of adjacent segment degeneration was observed in three segments (6.25%; two infra-adjacent segments and one intermediate segment). No case had neurological deterioration postoperatively. No implant failure or migration was observed during follow-up. CONCLUSIONS:: Treatment of two noncontiguous levels of CDDD with skip-level ACDF with self-locking stand-alone cages achieved good clinical and radiological outcomes including a high fusion rate, low complication rate, and excellent maintenance of spinal curvature and intervertebral height.

Concepts: Line, Segment, Discectomy, Time, Arithmetic mean, Deterioration, Anterior cervical discectomy and fusion, Degenerative disc disease

26

The homology of three somatic systems in Schizomida is studied yielding the following results: (1) proposal of homology and chaetotaxy of abdominal setae in Surazomus; (2) revision of the cheliceral chaetotaxy in Schizomida, with suggestion of new homology scheme between Hubbardiidae and Protoschizomidae, description of a new group of setae in Hubbardiinae (G7), and division of setae group 5 in two subgroups, G5A and G5B; (3) proposal of segmental homology between trimerous and tetramerous female flagellum in Hubbardiinae with association of segment III of tri-segmented species to segments III + IV of tetra-segmented species. Considerations about the dorsal microsetae on the male flagellum are made. The genus Surazomus in Ecuador is revised. The sympatric species Surazomus palenque sp. nov. and S. kitu sp. nov. (Ecuador, Pichincha) are described and illustrated. The female of S. cuenca (Rowland and Reddell, 1979) is described, with two new distributional records for the species. Surazomus cumbalensis (Kraus, 1957) is recorded for the first time from Ecuador (Pichincha).

Concepts: Cantons of Ecuador, Human, Following, Segment, Male, Group, Ecuador, Quito

25

Intraoperative electrocardiographic monitoring is considered a standard of care. However, there are no evidence-based algorithms for using intraoperative ST segment data to identify patients at high risk for adverse perioperative cardiac events. Therefore, we performed an exploratory study of statistical measures summarizing intraoperative ST segment values determine whether the variability of these measurements was associated with adverse postoperative events. We hypothesized that elevation, depression, and variability of ST segments captured in an anesthesia information management system are associated with postoperative serum troponin elevation.

Concepts: Part, Exploratory research, Segment, Sociology, Statistics

23

Hair and nails are often used to prove drug intake over several months. However, it is impossible to determine the day of drug intake by conventional segmental analysis of bulk samples. To improve this segmental analysis, we prepared accurate 0.4-mm hair and 0.2-mm nail segments, which correspond to their respective growth rates of 1-2 days, using a tissue slicer. The aim of this study was to develop an efficient method to extract drugs from a single sub-millimeter segment of hair and nail. Hair and nails were collected from a subject who was administered a single dose of chlorpheniramine. Four drug extraction methods based on different principles such as sonication, microwaves, micropulverization, and alkaline dissolution were compared. Short-duration sonication followed by long-duration soaking served the aim. Drug extraction from a sub-millimeter segment was performed in three steps as follows: a segment was first washed, followed by sonication for 10 min soaking in the extraction solution for 24 h. The drug concentrations in the three extracts from each segment were quantified using high performance liquid chromatography-tandem mass spectrometry. Each concentration was displayed on a single hair strand and a single nail block so that the first, second, and third extracts corresponded to components on the surface, in the outer layer, and within the sample, respectively. The distribution of chlorpheniramine in a hair successfully reflected the intake history. This method can be used in the future to measure the detailed distribution of drugs in a single hair and nail.

Concepts: Mass spectrometry, Hair, Extract, Segment, Drug, Pharmacology, Concentration, Liquid chromatography-mass spectrometry

8

The swimming locomotion of fish involves a complex interplay between a deformable body and induced flow in the surrounding fluid. While innovative robotic devices, inspired by physicomechanical designs evolved in fish, have been created for underwater propulsion of large swimmers, scaling such powerful locomotion into micro-/nanoscale propulsion remains challenging. Here, a magnetically propelled fish-like artificial nanoswimmer is demonstrated that emulates the body and caudal fin propulsion swimming mechanism displayed by fish. To mimic the deformable fish body for periodic shape changes, template-electrosynthesized multisegment nanowire swimmers are used to construct the artificial nanofishes (diameter 200 nm; length 4.8 μm). The resulting nanofish consists a gold segment as the head, two nickel segments as the body, and one gold segment as the caudal fin, with three flexible porous silver hinges linking each segment. Under an oscillating magnetic field, the propulsive nickel elements bend the body and caudal fin periodically to generate travelling-wave motions with speeds exceeding 30 μm s(-1) . The propulsion dynamics is studied theoretically using the immersed boundary method. Such body-deformable nanofishes exhibit a high swimming efficiency and can serve as promising biomimetic nanorobotic devices for nanoscale biomedical applications.

Concepts: Segment, Gold, Chemical element, Ferromagnetism, Magnet, Deformable body, Magnetism, Magnetic field