bluuebunny/crossref_metadata_2025 huggingface dataset:
Density Functional Studies of Coenzyme NADPH and Its Oxidized Form NADP+: Structures, UV–Vis Spectra, and the Oxidation Mechanism of NADPH
Authors: Cao Xiaoyan , Wu Liangliang , Zhang Jun , Dolg Michael
Published: November 2019

Density functional theory has been used to study the biologically important coenzyme NADPH and its oxidized form NADP+. It was found that free NADPH prefers a compact structure in gas phase and exists in more extended geometries in aqueous solution. Ultraviolet–visible absorption spectra in aqueous solution were calculated for NADPH with an explicit treatment of 100 surrounding water molecules in combination with the COSMO solvation model for bulk hydration effects. The obtained spectra using the B3LYP hybrid density functional agree quite well with experimental data. The changes of Gibbs free energies ΔG in reactions of NADPH with O2 observed experimentally in cardiovascular and in chemical systems, that is, NADPH + 2 3O2 → NADP+ + 2 O2− + H+ and NADPH + 1O2 + H+ → NADP+ + H2O2, respectively, were calculated. The NADPH oxidation reaction in the cardiovascular system cannot proceed without activation since the obtained ΔG is positive. The reaction of NADPH in the chemical system with singlet oxygen was found to proceed in two ways, each consisting of two steps, that is, NADPH firstly reacts with 1O2 barrierlessly to form NADP+ and HO2−, from which H2O2 is formed in a spontaneous reaction with H+, or 1O2 and H+ initially form 1HO2+, which further reacts with NADPH to yield NADP+ and H2O2. © 2019 The Authors. Journal of Computational Chemistry published by Wiley Periodicals, Inc.
Hope, optimism, self‐efficacy, and posttraumatic stress disorder: A meta‐analytic review of the protective effects of positive expectancies
Authors: Gallagher Matthew W. , Long Laura J. , Phillips Colleen A.
Published: November 2019

Objective

The present meta‐analysis consolidated research examining how positive expectancies (e.g., hope, self‐efficacy, and optimism) may protect against the development of posttraumatic stress disorder (PTSD).

Method

Articles were identified by searching PILOTS, PsycINFO, PubMed, and ProQuest Dissertations and Theses databases.

Results

Aggregated results from 154 studies indicated that positive expectancies were associated with lower levels of PTSD symptoms. This relationship was stronger for coping‐specific self‐efficacy (k = 38,r = −.49; −.54 to −.43) and hope (k = 20,r = −.34; −.39 to −.28) compared with general self‐efficacy (k = 45,r = −.25; −.30 to −.20) and optimism (k = 59,r = −.29; −.33 to −.25) when examining cross‐sectional studies, and results were consistent in prospective studies. Age and gender did not moderate the cross‐sectional relationships.

Conclusions

These findings indicate that positive expectancies predict post‐trauma resilience. Future research should identify moderators and examine positive expectancies as mechanisms of change in therapy.
Scanning electron microscopy and energy‐dispersive X‐ray spectroscopy analysis of electrochemically etched graphite tips created from pencil lead
Authors: Sobola Dinara , Kaspar Pavel , Tofel Pavel , Holcman Vladimír
Published: November 2019

Modern day pencil lead is a material of many possibilities. Manufacture process is fast, easy, and well established, yet the full potential of its use still remains to be uncovered. Graphite content ratio to binding clays determines basic properties of the lead like its toughness and color, but more interesting qualities like conductivity and reactivity as well. Properly employed electrochemical etching with a bubble membrane creates sharp and smooth graphite tips, which can be, given enough graphite content, used as probes in several measurement techniques. Observing and adjusting the tip creation process and the results for use in further research are the objectives of this paper.
Observations on the recovering lumbar spinal cord of lizards show multiple origins of the cells forming the bridge region including immune cells
Authors: Alibardi Lorenzo
Published: November 2019

After transection the lumbar spinal cord of lizards forms a bridge of connective and nervous tissues between the severed proximal and distal ends of the cord. The types of proliferating cells activated in the injured spinal cord have been analyzed using light and ultrastructural immunolabeling for 5BrdU and nestin from 11 to 34 days after injury, when recovery of some hindlimb movements has occurred. At 11–22 days post‐transection an intense proliferation of glial, immune and meningeal cells takes place. Nestin is almost absent in the normal spinal cord but becomes detectable at 11–34 days postinjury in ependymal and sparse glial cells located in the bridge region. At 11–22 days postinjury also numerous macrophages, lymphocytes, and some plasma cells appear proliferating during the intense inflammatory and antimicrobial phase. Phagocytosis within the injured spinal cord probably decreases inflammation and may indirectly promote axonal regeneration. Proliferating cells likely derive from precursor or stem elements of the reactive ependymal epithelium, but also from glial cells and meningeal fibroblasts. This is indicated by the presence of 5BrdU‐long retaining labeling cells of glial and fibroblast types located in the stumps of the spinal cord and in the bridge. The present observations suggest that meningeal, ependymal, and numerous glial cells are the precursors of those forming the bridge region. Among glial cells, sparse oligodendrocytes myelinating the few axons present at 34 day after the injury also appear capable to proliferate. The myelinated axons are probably involved in the limited but important functional recovery of limb movements observed after 30–90 days postinjury.
Development of pancreatic acini in embryos of the grass snake Natrix natrix (Lepidosauria, Serpentes)
Authors: Kowalska Magdalena , Rupik Weronika
Published: November 2019

This study report about the differentiation of pancreatic acinar tissue in grass snake, Natrix natrix, embryos using light microscopy, transmission electron microscopy, and immuno‐gold labeling. Differentiation of acinar cells in the embryonic pancreas of the grass snake is similar to that of other amniotes. Pancreatic acini occurred for the first time at Stage VIII, which is the midpoint of embryonic development. Two pattern of acinar cell differentiation were observed. The first involved formation of zymogen granules followed by cell migration from ducts. In the second, one zymogen granule was formed at the end of acinar cell differentiation. During embryonic development in the pancreatic acini of N. natrix, five types of zymogen granules were established, which correlated with the degree of their maturation and condensation. Within differentiating acini of the studied species, three types of cells were present: acinar, centroacinar, and endocrine cells. The origin of acinar cells as well as centroacinar cells in the pancreas of the studied species was the pancreatic ducts, which is similar as in other vertebrates. In the differentiating pancreatic acini of N. natrix, intermediate cells were not present. It may be related to the lack of transdifferentiation activity of acinar cells in the studied species. Amylase activity of exocrine pancreas was detected only at the end of embryonic development, which may be related to animal feeding after hatching from external sources that are rich in carbohydrates and presence of digestive enzymes in the egg yolk. Mitotic division of acinar cells was the main mechanism of expansion of acinar tissue during pancreas differentiation in the grass snake embryos.
Left ventricular pacing in patients with preexisting tricuspid valve disease
Authors: Li Tony Y. W. , Seow Swee Chong , Singh Devinder , Yeo Wee Tiong , Kojodjojo Pipin , Lim Toon Wei
Published: November 2019

Background

Conventional right ventricular (RV) pacing is increasingly recognised to cause tricuspid valve (TV) injury or dysfunction, in part due to the need to pass the lead through the valve. This may be especially problematic in patients with preexisting TV disease or prior TV surgery. An alternative in this situation is to implant a left ventricular (LV) lead instead of ventricular pacing.

Methods

We performed a single‐center retrospective analysis of 26 patients with tricuspid valve surgery/disease who received a LV pacing lead in the coronary veins to avoid crossing the tricuspid valve, with or without a right atrial lead. A matched control population was obtained from patients receiving conventional right ventricular pacing and outcomes were compared. Main outcomes of interest were lead stability, electrical lead parameters and change in echocardiographic parameters such as left ventricular ejection fraction (LVEF) during long‐term follow‐up.

Results

Successful left ventricular pacing was established in 25 out of the 26 cases with one case converted to a RV lead due to lead dislodgement. During the 2.96 ± 1.0 year follow‐up, 24 of 25 (96.0%) leads were functional with stable pacing and sensing parameters, and 1 of 25 (4.0%) was extracted for due to device infection following an episode of thrombophlebitis.

Conclusion

We conclude that in patients with existing tricuspid valve disease or surgery, ventricular pacing via the coronary veins is a feasible, safe, and reliable alternative to right ventricular pacing.
Performance of CMIP5 wind speed from global climate models for the Bay of Bengal region
Authors: Krishnan Athira , Bhaskaran Prasad K.
Published: November 2019

Realistic estimates of surface wind speed (WS) are an essential prerequisite for process‐based air–sea interaction studies and numerical modelling needs. In this context, historical and projected WS estimates obtained from global and regional climate models warrant proper assessment and necessary bias corrections before it can be optimally used for rigorous analysis and research needs. Adequate evaluation and bias correction of WS estimates are therefore crucial to understand the extremes. For example, they have direct implications on extreme wind‐wave characteristics that can influence the coastal zones. The present study performed a detailed evaluation of WS obtained from the Coupled Model Intercomparison Project Fifth Phase (CMIP5) products to assess their projections for the Bay of Bengal region. A suite of global climate models (GCMs) is employed to generate the CMIP5 projections under four Representative Concentrative Pathways (RCPs) of 2.6, 4.5, 6.0, and 8.5 and based on differential CO2 emission scenarios. The present study also used the Research Moored Array for African–Asian–Australian Monsoon Analysis and Prediction (RAMA) buoys located in the central Bay of Bengal in order to validate and skill assess the CMIP5 wind products under varying RCPs. Besides, an intercomparison exercise that was performed between RAMA buoys data and merged satellite altimeter data from the French Research Institute for Exploitation of the Sea/Laboratory of Oceanography from Space (IFREMER/CERSAT) provided the necessary confidence to ascertain the quality of CMIP5 WS products. The study signifies that a moderate positive correlation was noticed in the WS comparison between CMIP5 GCM products and the RAMA buoys (maximum correlation of .64), and the correlation factor varied between the suite of models used in CMIP5 experiments. This exercise would provide detailed know‐how on the performance of various GCMs and also provide a basis to select the best performing GCMs for the Bay of Bengal region. Analysis of the upper 10% (90th percentile) showed a maximum underestimation/overestimation of 2.5 and 1.5 m·s−1, respectively, for WS comparison between CMIP5 and RAMA buoys data. Probability density of WS data fitted to Weibull distribution showed an increase of moderate WS (6–8 m·s−1) during the period of study. Although the CMIP5 GCMs are not able to represent the contemporary WS climatology satisfactorily, the models such as HadGEM2‐ES, HadGEM2‐CC, CanESM2, and ACCESS‐1.3 showed the best performance concerning near‐surface WS for the Bay of Bengal region.
Direct and indirect luminescence dating of tephra: A review
Authors: Bösken Janina Johanna , Schmidt Christoph
Published: November 2019

In Quaternary studies, tephras are widely used as marker horizons to correlate geological deposits. Therefore, accurate and precise dating is crucial. Among radiometric dating techniques, luminescence dating has the potential to date tephra directly using glass shards, volcanic minerals that formed during the eruption or mineral fragments that originate from the shattered country rock. Moreover, sediments that frame the tephra can be dated to attain an indirect age bracket. A review of numerous luminescence dating studies highlights the method's potential and challenges. While reliable direct dating of volcanic quartz and feldspar as a component in tephra is still methodically difficult mainly due to thermal and athermal signal instability, red thermoluminescence of volcanic quartz and the far‐red emission of volcanic feldspar have been used successfully. Furthermore, the dating of xenolithic quartz within tephra shows great potential. Numerous studies date tephra successfully indirectly. Dating surrounding sediments is generally straightforward as long as samples are not taken too close to the tephra horizons. Here, issues arise from the occurrence of glass shards within the sediments or unreliable determination of dose rates. This includes relocation of radioelements, mixing of tephra into the sediment and disregarding different dose rates of adjacent material.
Validity testing of a three‐dimensionally printed endoscopic sinonasal surgery simulator
Authors: Alwani Mohamedkazim M. , Svenstrup Thomas J. , Bandali Elhaam H. , Sharma Dhruv , Higgins Thomas S. , Wu Arthur W. , Shipchandler Taha Z. , Illing Elisa A. , Ting Jonathan Y.
Published: November 2019

Objectives/Hypothesis

To assess the face, content, construct, and concurrent validity of the PHACON Sinonasal Surgery Simulator (SNSS).

Study Design

Prospective cohort study.

Methods

A total of 12 otolaryngology residents were recruited to perform sinonasal surgery on the simulator followed by cadaveric heads. Resident performances were recorded and de‐identified. Face and content validities were evaluated based on 5‐point Likert scale questionnaires. The recordings were evaluated by extramural expert rhinologists based on a validated Global Rating Scale (GRS). These results were analyzed and compared to assess construct and concurrent validity.

Results

The appearance of anatomic structures was rated as realistic by 75% of all participants, while only 30% and 41.7% rated the mucosal and bony tissues as realistic, respectively. A total of 91.7% of participants found the model useful for teaching anatomy, while 66.7% said it was useful for teaching operative technique. Construct validity was confirmed by showing significant differences in performance between the novice and experienced groups. Concurrent validity was confirmed by showing significant correlation between performance on the model and gold standard (i.e. cadaver head).

Conclusions

This study demonstrates the face, content, concurrent, and construct validity of a 3D‐printed SNSS. Although this model has the potential to be a valuable tool in endoscopic sinus surgery training for otolaryngology residents, improvements are required with respect to the quality of simulated mucosal tissue as well as the simulated anatomy of the fronto‐ethmoid compartment

Level of Evidence: NA

Laryngoscope, 2019
Impact of primary tumor‐specific growth rate on treatment failure for nonoropharyngeal head and neck cancers
Authors: Roldan Claudia S. , Chen Jie Jane , Fareed M. Mohsin , Hameed M. Yahya , Churilla Thomas M. , Lango Miriam N. , Galloway Thomas J.
Published: November 2019

Objectives

To investigate the prognostic impact of primary tumor‐specific growth rate (TSGR) on treatment outcomes after definitive radiation therapy (RT) for nonoropharyngeal squamous cell carcinoma (non‐OPSCC).

Methods

The diagnostic tumor and nodal volumes of 39 non‐OPSCC patients were contoured and compared to corresponding RT planning scan volumes to determine TSGR. Overall survival (OS), disease‐free survival (DFS), and local recurrence‐free survival were evaluated according to the Kaplan‐Meier method; and hazard ratios (HR) were estimated using Cox regression. Based on the 75th percentile TSGR of 2.18%, we stratified patients into a high TSGR group (≥ 2.18% per day) and low TSGR group (< 2.18% per day).

Results

The median follow‐up was 22 months (range: 1–86 months) and median time between diagnostic and simulation computed tomography scans was 22 days (range: 7–170 days). Median RT dose was 70 Gy (range: 60–79.2 Gy). Based on the 75th percentile TSGR, OS at median follow‐up was 50.0% for the high TSGR group compared to 92.5% for the low TSGR group (HR [95% confidence interval (CI)] = 2.12[1.16–11.42], P = 0.018). There was a trend toward worse DFS at median follow‐up for the high versus low TSGR groups, at 55.6% and 82.3%, respectively (HR [95% CI] = 2.29[0.82–6.38], P = 0.103).

Conclusion

Our study contributes to growing literature on TSGR as a temporal biomarker in patients with non‐OPSCC. Patients with high TSGR ≥2.18% per day have significantly worse OS compared to those with TSGR below this threshold. Efforts to address treatment initiation delays may benefit patients with particularly aggressive and rapidly growing tumors.

Level of Evidence

4 Laryngoscope, 130:2378–2384, 2020
Biotic formation of methylmercury: A bio–physico–chemical conundrum
Authors: Bravo Andrea G. , Cosio Claudia
Published: November 2019

Mercury (Hg) is a natural and widespread trace metal, but is considered a priority pollutant, particularly its organic form methylmercury (MMHg), because of human's exposure to MMHg through fish consumption. Pioneering studies showed the methylation of divalent Hg (HgII) to MMHg to occur under oxygen‐limited conditions and to depend on the activity of anaerobic microorganisms. Recent studies identified the hgcAB gene cluster in microorganisms with the capacity to methylate HgII and unveiled a much wider range of species and environmental conditions producing MMHg than previously expected. Here, we review the recent knowledge and approaches used to understand HgII‐methylation, microbial biodiversity and activity involved in these processes, and we highlight the current limits for predicting MMHg concentrations in the environment. The available data unveil the fact that HgII methylation is a bio‐physico‐chemical conundrum in which the efficiency of biological HgII methylation appears to depend chiefly on HgII and nutrients availability, the abundance of electron acceptors such as sulfate or iron, the abundance and composition of organic matter as well as the activity and structure of the microbial community. An increased knowledge of the relationship between microbial community composition, physico‐chemical conditions, MMHg production, and demethylation is necessary to predict variability in MMHg concentrations across environments.
Microbial community composition and functional potential in Bothnian Sea sediments is linked to Fe and S dynamics and the quality of organic matter
Authors: Rasigraf Olivia , van Helmond Niels A. G. M. , Frank Jeroen , Lenstra Wytze K. , Egger Matthias , Slomp Caroline P. , Jetten Mike S. M.
Published: November 2019

The Bothnian Sea is an oligotrophic brackish basin characterized by low salinity and high concentrations of reactive iron, methane, and ammonium in its sediments, enabling the activity and interactions of many microbial guilds. Here, we studied the microbial network in these sediments by analyzing geochemical and microbial community depth profiles at one offshore and two near coastal sites. Analysis of 16S rRNA gene amplicons revealed a distinct depth stratification of both archaeal and bacterial taxa. The microbial communities at the two near coastal sites were more similar to each other than the offshore site, which is likely due to differences in the quality and rate of organic matter degradation. The abundance of methanotrophic archaea of the ANME‐2a clade was shown to be related to the presence of methane and varied with sediment iron content. Metagenomic sequencing of sediment‐derived DNA from below the sulfate–methane transition zone revealed a broad potential for respiratory sulfur metabolism via partially reduced sulfur species. The potential for nitrogen cycling was dominated by reductive processes via a truncated denitrification pathway encoded exclusively by bacterial lineages. Gene‐centric fermentative metabolism analysis indicated a potential importance for acetate, formate, alcohol, and hydrogen metabolism. Methanogenic/‐trophic pathways were dominated by Methanosaetaceae, Methanosarcinaceae, Methanomassiliicoccaceae, Methanoregulaceae, and ANME‐2 archaea. Our results indicated flexible metabolic capabilities of core microbial community taxa, which could adapt to changing redox conditions, and with a spatial and depth distribution that is likely governed by the quality and input of available organic substrates and, for ANME‐2, of iron oxides.
Corneal Damage Effects Induced by a 770–2,500 nm Supercontinuum Light Source
Authors: Jiao Luguang , Fan Yan , Wang Jiarui , Yang Zaifu
Published: November 2019

Background and Objectives

Widespread applications of supercontinuum (SC) source lead to the possibility of ocular damages. However, the corneal damage effects induced by SC have not been explored before. The objectives of this study are to determine the rabbit corneal injury threshold for SC radiation and to examine whether the existing safety guidelines and standards are suitable for the hazard evaluation of this new kind of light source.

Study Design/Materials and Methods

A series of experiments was conducted in the New Zealand white rabbit model to determine the corneal damage thresholds induced by a 770–2,500 nm SC source, with a corneal 1/e beam diameter of 0.37 mm. Through slit‐lamp biomicroscope, optical coherence tomography (OCT), and histopathology the corneal damage characteristics at the threshold level were revealed. By employing the action spectra determined through the analysis of safety guidelines and standards, the damage thresholds for SC source could be compared with the corresponding exposure limits.

Results

The determined damage thresholds given in terms of the peak radiant exposure for exposure durations of 2.0 and 10.0 seconds were 2.1 × 103 and 7.4 × 103 J/cm2, respectively. At threshold level, corneal damages involved the epithelium and the shallower stroma, and no obvious changes could be found in the deep stroma, Descemet's membrane, and endothelium.

Conclusions

The exposure limits for the anterior parts of the eye in the wavelength range of 700–1,200 nm are overly conservative. The obtained results contribute to the knowledge base for the hazard evaluation of SC source. Lasers Surg. Med. © 2019 Wiley Periodicals, Inc.
Innovative 1064‐nm Nd:YAG Laser Significantly Improves Keratosis Pilaris, A Randomized, Double‐Blind, Sham‐Irradiation‐Controlled Trial
Authors: Maitriwong Praewvanid , Tangkijngamvong Natsinee , Asawanonda Pravit
Published: November 2019

Background and Objective

Keratosis pilaris (KP) is a common follicular disorder for which various topical agents and energy‐based devices have been used with some efficacy. To evaluate the efficacy of a novel 1064‐nm Nd:YAG laser for the reduction of skin roughness, erythema, and hyperpigmentation in KP subjects.

Study Design/Materials and Methods

Twenty‐three subjects with untreated KP on the upper outer arms participated in a randomized, single‐blind fashion. One arm of each subject was divided into upper and lower parts. One part was randomized to be treated with an innovative 1064‐nm Nd:YAG laser, while the other part received sham irradiation. Subjects received four consecutive treatments at 4‐week intervals. Antera3D was used to measure skin roughness, erythema, and hyperpigmentation at baseline and 4 weeks after the last treatment. Moreover, clinical outcomes were also evaluated by subjects' Global Improvement Score (GIS) and subjects' satisfaction grading scores.

Results

Twenty‐three subjects completed the study. There was statistically significant reduction of skin roughness measured by Antera3D compared with control group (P < 0.001). There were statistically significant improvements of skin roughness, erythema, hyperpigmentation, and overall appearances graded by subjects' Global Improvement Score (P < 0.001 all). Subjects' satisfaction scores were graded significantly better in treatment parts (P < 0.001). No adverse events including burning, bulla, erosion, post‐inflammatory hyper/hypopigmentation, and scar formation developed in any subjects throughout the study period.

Conclusion

This innovative 1064‐nm Nd:YAG laser has proved to significantly and safely reduce skin roughness in Thai KP subjects compared with control after four sessions. Lasers Surg. Med. © 2019 Wiley Periodicals, Inc.
Liver Transplantation in Children With Propionic Acidemia: Medium‐Term Outcomes
Authors: Curnock Richard , Heaton Nigel D. , Vilca‐Melendez Hector , Dhawan Anil , Hadzic Nedim , Vara Roshni
Published: November 2019

Liver transplantation (LT) for patients with propionic acidemia (PA) is an emerging therapeutic option. We present a retrospective review of patients with PA who underwent LT at a tertiary liver center between 1995 and 2015. A total of 14 children were identified (8 males) with median age at initial presentation of 3 days (range, 0‐77 days). Pretransplant median protein restriction was 1 g/kg/day (range, 0.63‐1.75 g/kg/day), 71% required supportive feeding, and 86% had developmental delay. Frequent metabolic decompensations (MDs) were the main indication for LT with a median age at transplantation of 2.4 years (range, 0.8‐7.1 years). Only 1 graft was from a living donor, and 13 were from deceased donors (4 auxiliary). The 2‐year patient survival was 86%, and overall study and graft survival was 79% and 69%, respectively. Three patients died after LT: at 43 days (biliary peritonitis), 225 days (acute‐on‐chronic rejection with multiorgan failure), and 13.5 years (posttransplant lymphoproliferative disease). Plasma glycine and propionylcarnitine remained elevated but reduced after transplant. Of 11 survivors, 5 had at least 1 episode of acute cellular rejection, 2 sustained a metabolic stroke (with full recovery), and 3 developed mild cardiomyopathy after LT. All have liberalized protein intake, and 9 had no further MDs: median episodes before transplant, 4 (range, 1‐30); and median episodes after transplant, 0 (range, 0‐5). All survivors made some developmental progress after LT, and none worsened at a median follow‐up of 5.8 years (range, 2‐23 years). LT in PA significantly reduces the frequency of MDs, can liberalize protein intake and improve quality of life, and should continue to be considered in selected cases.
Impact of Dynamic Bond Concentration on the Viscoelastic and Mechanical Properties of Dynamic Poly(alkylurea‐co‐urethane) Networks
Authors: Chen Lifeng , Zhang Longhe , Griffin Philip J. , Rowan Stuart J.
Published: November 2019

Polymer networks containing dynamic covalent bonds do not exhibit traditional thermoset material properties. Such dynamic covalent networks have the ability to undergo stress relaxation processes associated with dynamic covalent bond exchange, imparting these materials with adaptive/responsive properties. Reported herein is an investigation on the effect that changing the amount of dynamic hindered alkylurea bonds has on the viscoelastic behavior of a series of poly(alkylurea‐co‐urethane) networks prepared by reacting a trifunctional isocyanate crosslinker with varying ratios of an N‐isopropyl amine endcapped poly(propylene glycol) and a poly(propylene glycol). Films that contain >50% dynamic alkylurea bonds (wrt. alkylurea + urethane bonds) exhibit facile reprocessability, while those films with <50% dynamic alkylurea bonds exhibit poor reprocessability under these same conditions. Analysis of the temperature‐dependent shear rheometry and uniaxial stress relaxation measurements demonstrates that the primary stress relaxation mode in these materials is linked to the dynamic bond exchange process. Interestingly, these films exhibit an increasingly rich viscoelastic spectrum with increasing fraction of non‐dynamic urethane bonds. In addition to the primary relaxation process an order‐of‐magnitude slower relaxation emerges, which is identified as being related to the relaxation of larger, permanently crosslinked polymeric clusters in an otherwise dynamic matrix.
Bendixson criterion in impulsive systems
Authors: Ding Changming , Duan Zhipeng , Pan Shiyao
Published: November 2019

Bendixson's condition on the nonexistence of periodic solutions for planar ordinary differential equations is extended to differential equations with impulse. Also, we use an example of predator‐prey model to illustrate our results.
A putative protein–RNA complex regulates posttranscriptional processing of cytochrome P450 aromatase (CYP19A1) in bovine granulosa cells
Authors: Sahmi Fatiha , Sahmi Malha , Gévry Nicolas , Sahadevan Pramod , Allen Bruce G. , Price Christopher A.
Published: November 2019

Follicle growth and granulosa cell health are dependent on the secretion of estradiol from granulosa cells. Estradiol is synthesized from androgen precursor by cytochrome P450 aromatase (CYP19A1), and in cattle CYP19A1 messenger RNA has a short half‐life but a long (3.5 kb) 3′‐untranslated region (3′UTR), suggesting that posttranscriptional regulation may be important for control of enzyme activity. We tested this hypothesis by inserting the CYP19A1 3′UTR and fragments thereof into a reporter vector between the end of the luciferase coding region and the polyadenylation signal. The full‐length aromatase 3′UTR suppressed luciferase activity to 10% of control levels, and smaller fragments showed that this inhibitory activity lies between +926 and +1134 of the 3′UTR. Protein–RNA cross‐linking experiments revealed that these 3′UTR fragments formed an RNA–protein complex of approximately 70 kDa that was present in granulosa cells but not in corpus luteum, lung, liver, kidney, pancreas, or bladder extracts. The RNA‐binding activity was specific to the 3′UTR, as shown by competition experiments with unlabeled RNA, and was present only in 3′UTR constructs that inhibited luciferase activity. These data suggest that posttranscriptional regulation is an important component of the control of CYP19A1 expression and involves protein binding to a specific sequence in the 3′UTR.
Simulation of Polymer Reactors Using the Compartment Modeling Approach
Authors: Cremer‐Bujara Esther , Biessey Philip , Grünewald Marcus
Published: November 2019

A compartment modeling approach based on computational fluid dynamics (CFD) simulations is applied to a simplified static mixer geometry. Compartments are derived from velocity fields obtained from cold CFD simulations. This methodology is based on the definition of periodic flow zones (PFZ) derived from the recurrent flow profile within the static mixer. In general, PFZ can be characterized by two different compartments: flow zones with hydrodynamic behavior of a tubular reactor and dead zones exhibiting a more continuous stirred tank reactor‐like characteristic. In CFD studies the influence of changing fluid properties, for example viscosity, on flow profile due to polymerization progress is considered. In the deterministic compartment model, the continuous flow profile within the static mixer is transformed to basic reactor models interconnected via an exchange stream. To reduce model complexity and the number of model parameters, constant volumes of compartments are assumed. Changes in hydrodynamics are considered by a variable exchange flow rate as a function of Re manipulating residence time in compartments. Simulation studies show the influence of decreasing exchange flow rates with polymerization progress, as Re decreases, resulting in a greater increase of viscosity in dead zones. The reactor performance is qualitatively represented by the simulation results.
Optimizing Delivery of Breast Milk for Premature Infants: Comparison of Current Enteral Feeding Systems
Authors: Abdelrahman Khaled , Jarjour Jane , Hagan Joseph , Yang Heeju , Sutton Danielle , Hair Amy
Published: November 2019

Background

Incomplete delivery of fat from expressed breast milk (EBM) during enteral feeding to premature neonates remains a significant problem. Feeding system manufacturers have introduced changes to the enteral syringe design to improve fat delivery that have not yet been evaluated in the literature.

Methods

This study compares percentage delivery of fat from EBM using 2 major enteral feeding systems in various configurations with silicone and polyurethane tubing material and ENFit and Legacy connection systems at 3 clinically relevant infusion rates.

Results

The percent of fat delivery from EBM was significantly higher for the eccentric syringe system than the concentric system (P = 0.036) but did not vary significantly across infusion rates (P = 0.081). Silicone tubing had a significantly higher percent of fat delivery than polyurethane tubing within the eccentric syringe system (P = 0.039) but did not vary significantly across infusion rates (P = 0.105). There was no significant difference between ENFit and Legacy connectors using eccentric syringes with silicone tubing (P = 0.360).

Conclusion

We demonstrate that changes to syringe design and tubing material are effective and improve fat delivery from EBM, which may result in improved growth and outcomes in premature infants. The eccentric syringe marginally improves fat delivery in comparison with the concentric syringe, and silicone tubing significantly improves fat delivery compared with polyurethane tubing.
Mechanical Microstructure Characterization of Discontinuous‐Fiber Reinforced Composites by means of Experimental‐Numerical Micro Tensile Tests
Authors: Schober Michael , Dittmann Kerstin , Gumbsch Peter , Kuboki Takashi , Hohe Jörg
Published: November 2019

The mechanical characteristics and especially the damage behavior of discontinuous‐fiber reinforced composites greatly depend on its constituents and also on its microstructural properties, namely the extent and distribution of fiber agglomerations, the fiber orientation distribution, and the fiber‐matrix interfaces. Several methods exist to individually analyze the different microstructural properties, such as µCT scanning to obtain the distribution of the fibers and their orientation and the Microbond test to obtain the interfacial characteristics. However, the interdependencies of the individual characteristics and the initiation of fracture with respect to the microstructure are still hard to analyze regarding a real composite structure. For this reason, the microscopic fracture behavior of a glass fiber reinforced sheet molding compound (SMC) shall be investigated by means of a micro tensile test. Therefore, a specimen with a gauge length of approx. 1 mm, 0.3 mm width and 0.1 mm thickness is extracted from a composite plaque and put to an in‐situ observed tensile test. With a finite element model of each specimen, including the position and orientation of each fiber, the fiber‐matrix‐interface characteristics are extracted with a reverse‐engineering approach. The tests show a microstructure‐specific fracture behavior, which depends on the fiber dispersion, the fiber orientation, and the fiber‐matrix interfaces. The numerical simulations well agree with the physical experiments, making the obtained parameters suitable for further simulations of the investigated structure on a larger scale.
Effects of a temperature cycle on a rotating shrink fit with FGM‐hub
Authors: Arslan Eray , Apatay Tunç , Mack Werner
Published: November 2019

Subject of the investigation is a rotating shrink fit with hollow cylindrical inclusion and functionally graded hub in a state of generalized plane strain. Elevated temperature during operation may have both a transient and – in case of partial plastification – a permanent influence on the interface pressure. These effects are exemplified by means of a shrink fit with steel/aluminum FGM‐hub.
Injectable hydrogels for targeted delivering of therapeutic molecules for tissue engineering and disease treatment
Authors: Mavlyanova Rukhshona , Yang Rufeng , Tao Tao , Aquib Md , Kesse Samuel , Maviah Mily Bazezy Joelle , Boakye‐Yiadom Kofi Oti , Farooq Muhammad Asim , Wang Bo
Published: November 2019

Hydrogels are cross‐linked three‐dimensional polymeric networks that play a vital role in solving the pharmacological and clinical limitations of the existing systems due to their unique physical properties such as affinity for biological fluids, tunable porous nature, high water content, ease of preparation, flexibility, and biocompatibility. Hydrogel also mimics the living natural tissue, which opens several opportunities for its use in biomedical areas. Injectable hydrogel allows temporal control and exceptional spatial arrangements and can offset hitches with established hydrogel‐based drug delivery systems. Here, we review the recent development of injectable hydrogels and their significance in the delivery of therapeutics such as cells, genes, and drug molecules and how these innovatory systems can complement the current delivery systems.
Improving outcomes of infections in cystic fibrosis in the era of CFTR modulator therapy
Authors: Saiman Lisa
Published: November 2019

Currently, available single and dual‐combination cystic fibrosis transmembrane conductance regulator (CFTR) modulator therapies have favorably altered the life course of individuals with cystic fibrosis (CF) by decreasing morbidities and increasing survival. However, even with CFTR modulator use, questions and challenges remain to optimize the management of lung infections. This review (a) identifies these ongoing challenges and discusses the current understanding of the potential impact of CFTR modulator therapy on infections; (b) describes ongoing research to optimize detection, diagnosis, and treatment of CF microorganisms; and (c) discusses strategies to develop new anti‐infective therapies. The CF Foundation has launched the Infection Research Initiative to fund research that will improve our understanding of the complex microbial ecology within the CF lung, improve detection of CF pathogens, optimize current treatment, including long‐term chronic therapies, and develop new anti‐infective therapies. Ongoing clinical trials to determine the optimal duration of treatment of pulmonary exacerbations and to diagnose and treat nontuberculous mycobacteria represent clinical research paradigms that could be used to answer other complex treatment questions. The anti‐infective pipeline includes both existing anti‐infective and non‐anti‐infective agents, many of which are proposed to have unique mechanisms of action in CF. Future studies plan to evaluate short‐ and long‐term clinical effectiveness and impact on infections, of the next generation of CFTR modulator therapy, the highly effective triple‐combination therapy, for individuals with CF, homozygous or heterozygous for F508del.
Equipment‐based route index of inherent safety
Authors: Athar Muhammad , Shariff Azmi M. , Buang Azizul , Hermansyah Heri
Published: November 2019

Process safety concept is used to deal with accident scenarios occurring as a result of loss containment. There are four tactics of process safety, and due to superior characteristics, the inherent theme is given priority at the preliminary design stage. In open literature, various methods have been proposed to identify the inherent safety level, and among these indexing methods are typically used. The reported indices have a shortcoming that these have not considered equipment characteristics for inherent safety assessment. Therefore, a new indexing method is proposed in this article to improve the quantification of inherent safety level. This index incorporates process, chemical, and equipment aspects to define the safety level of various process routes via the relative ranking. The proposed index has been tested on process routes to produce methyl methacrylate, which confirms the applicability of this index. The index would enable the practitioners to thoroughly analyze and compare the process routes to identify the inherently safer route.
Does moving in childhood and adolescence affect residential mobility in adulthood? An analysis of long‐term individual residential trajectories in 11 European countries
Authors: Bernard Aude , Vidal Sergi
Published: November 2019

The impact of childhood mobility on a range of life outcomes has been examined, but its influence on the likelihood to move in adulthood remains largely unknown. This paper examines the impact of changing residence in childhood on mobility levels in early and mid‐adulthood in 11 European countries. Drawing on nationally representative retrospective residential histories from the Study of Health, Ageing and Retirement in Europe (SHARE), the paper uses negative binomial regression to assess how the number and timing of moves from birth to age 17 affect the likelihood to move between the ages of 18 to 50 for individuals born between 1918 and 1957. While the level and timing of childhood moves vary between countries, childhood moves significantly increase the likelihood to move in adulthood in all our sample countries but Austria. The effect is particularly pronounced in low mobility countries in the south, east and centre of Europe where moving as a child is less common. While changing residence in adolescence is particularly influential, in some countries pre‐school relocations also have a long‐lasting effect on subsequent mobility. Conceptually, these results demonstrate the importance of viewing mobility as a cumulative process that takes place over the entire life‐course of individuals. Drawing on key migration and mobility concepts, we formulate a schematic decision‐making framework that traces the relationship between past and future moves. We conclude that the impact of changing residence in childhood on mobility behaviour later in life could contribute to reinforcing diverging trends in mobility levels across Europe.
Study of Structural and Magnetotransport Properties of Fe(Te, Se) Single Crystals
Authors: Kumar Rohit , Varma Ghanshyam Das
Published: November 2019

Single‐crystalline samples of nominal compositions FeTe0.88 and FeTe1−xSex are synthesized using the self‐flux method. The activation energy of the flux flow is estimated using the Arrhenius relation as well as by the modified thermally activated flux flow (TAFF) model. The field dependence of U0 shows transition from single to collective vortex pinning at a magnetic field of ≈2 T. The analysis of field‐dependent U0 data reveals the planar and the point defect magnetic field regions for both the models. The modified TAFF model is used to study the 2D and 3D behavior of the vortex state for all the superconducting samples. The single‐crystalline FeTe0.80Se0.20 and FeTe0.60Se0.40 samples show 3D behavior, whereas the FeTe0.40Se0.60 crystal shows 2D behavior. The vortex phase diagrams of all the superconducting samples are obtained by analyzing the magnetotransport data. The vortex phase diagrams reveal transitions from the unpinned to pinned vortex liquid state and the vortex liquid to vortex glass state. Below T*, the critical exponent s is in good agreement with q values for 2D/3D behavior of vortex states of all the superconducting samples.
Statistical inference on progressive‐stress accelerated life testing for the logistic exponential distribution under progressive type‐II censoring
Authors: Kumar Mahto Amulya , Dey Sanku , Mani Tripathi Yogesh
Published: November 2019

The accelerated life testing (ALT) is an efficient approach and has been used in several fields to obtain failure time data of test units in a much shorter time than testing at normal operating conditions. In this article, a progressive‐stress ALT under progressive type‐II censoring is considered when the lifetime of test units follows logistic exponential distribution. We assume that the scale parameter of the distribution satisfying the inverse power law. First, the maximum likelihood estimates of the model parameters and their approximate confidence intervals are obtained. Next, we obtain Bayes estimators under squared error loss function with the help of Metropolis‐Hasting (MH) algorithm. We also derive highest posterior density (HPD) credible intervals of the model parameters. Monte Carlo simulations are performed to compare the performances of the proposed methods of estimation. Finally, one data set has been analyzed for illustrative purposes.
Multi‐instance multi‐label learning for surgical image annotation
Authors: Loukas Constantinos , Sgouros Nicholas P.
Published: November 2019

Background

Various techniques have been proposed in the literature for phase and tool recognition from laparoscopic videos. In comparison, research in multilabel annotation of still frames is limited.

Methods

We describe a framework for multilabel annotation of images extracted from laparoscopic cholecystectomy (LC) videos based on multi‐instance multiple‐label learning. The image is considered as a bag of features extracted from local regions after coarse segmentation. A method based on variational Bayesian gaussian mixture models (VBGMM) is proposed for bag representation. Three techniques based on different feature extraction and bag representation models are employed for comparison.

Results

Four anatomical structures (abdominal wall, gallbladder, fat, and liver bed) and a tool‐like object (specimen bag) were annotated in 482 images. Our method achieved the best performance on single label accuracy: 0.87 (highest) and 0.69 (lowest). Moreover, the performance was >20% higher in terms of four multilabel classification error metrics (one‐error, ranking‐loss, hamming‐loss, and coverage).

Conclusions

Our approach provides an accurate and efficient image representation for multilabel classification of still images captured in LC.
Frequency‐dependent fault detection for networked systems under uniform quantization and try‐once‐discard protocol
Authors: Long Yue , Park Ju H. , Ye Dan
Published: November 2019

This paper is concerned with the frequency‐dependent fault detection scheme for networked systems under uniform quantization and try‐once‐discard protocol scheduling. By considering the communication constraint and the data node scheduling, a switched system is firstly modeled to characterize the dynamic features of the whole system. The switching function of the derived system is determined by the try‐once‐discard protocol. For this class of system, a sufficient condition to ensure the exponentially ultimately boundedness is established. With the aid of some novel analysis processes, sufficient conditions to characterize the desired finite frequency performances, which transform the frequency‐domain restrictions into time‐domain conditions, are subsequently developed. Then, the fault detection filters corresponding to the transmission nodes are synthesized by solving an optimization problem. Finally, an application to VTOL aircraft is presented to illustrate the effectiveness of the proposed fault detection strategy.
A trajectory‐based method for constructing null controllable regions
Authors: Homer Tyler , Mahmood Maaz , Mhaskar Prashant
Published: November 2019

The problem of determining a system's set of stabilizable states, the null controllable region (NCR), is intricately related to the problem of determining control Lyapunov functions. In this paper, we address the problem of construction of the NCR for control‐affine nonlinear systems with input constraints. To this end, we explain how the boundary of the NCR is covered by time‐optimal trajectories. To construct the NCR, we employ an algorithm based on Pontryagin's minimum principle, which integrates optimal trajectories of a special smooth system in reverse time from the boundary of an initial NCR estimate. We illustrate this algorithm with linear and nonlinear system examples.