bluuebunny/crossref_metadata_2025 huggingface dataset:
Nonlinear Responses of An Unbalanced Overhung Rotor-Short Journal Bearing System with Some Bifurcation Results
Authors: Atayagul P , Kamnerdthong T , Songschon S
Published: July 2020

Both autonomous and non-autonomous nonlinear systems display complex responses including the transient and long run responses. An overhung rotor-short journal bearing system (ORSJB) is the excellent paradigm exhibiting nonlinear responses and of practical importance. The unbalanced overhung rotor-journal bearing system is formulated by using modified Laval-Jeffcott rotor model. The nonlinear fluid forces model of the short journal bearing is adopted and rearranged in a suitable form for numerical analysis. This paper investigates numerically a bifurcation point, transient and long run responses of the ORSJB system. The rotational speed is preferable bifurcation parameter herein. The ORSJB system without unbalanced eccentricity for the selected parameters yields the bifurcation value of Ω = 3.0091. Limits cycles in the long-run responses with eU
=0.002 m and without unbalanced eccentricity at long run are presented in the bifurcation regime at the speed of Ω = 6.6869 and Ω = 0.01671 respectively. The transient response with eU
=0.002 m at the speed of Ω = 4.7142is elucidated. The evident results in this paper give only a partial view of bifurcation behaviours. Bifurcation analysis is a useful tool for design and operation overhung rotor dynamic systems.
Effects of Waveguide Position on Electric Field and Temperature Profile in Natural Rubber Gloves during Vulcanization Process Using Microwave Energy
Authors: Keangin P. , Narumitbowonkul U. , Rattanadecho P.
Published: July 2020

Natural rubber gloves (NRG) become a broader industry with fierce competition and demands. The vulcanization process is the most important and takes the longest time in the cycle period of the NRG manufacturing process, so it becomes of paramount importance to improve this process. The purpose of this research is to experimentally and computationally study the characteristics of the electric field as well as temperature profile in NRG during the microwave vulcanization process. The effects of position of waveguide placement are investigated for nine different positions. The experiment of NRG microwave vulcanization is performed for temperature distribution measurement. Three-dimensional models of NRG and microwave oven are considered. Finite element method (FEM) is utilized to solve a mathematic model of the transient Maxwell’s equation coupled with the transient heat transfer equation in order to determine the electric field and temperature profile via computer simulation. The computer simulation results are validated against the experimental results. The validation confirms that the computational model is able to represent the practical transport phenomena in NRG with high accuracy. The outcomes clearly reveal that the position of waveguide effects on the electric field as well as temperature profile in NRG during the microwave vulcanization process. The positioning of waveguides on both the front and backsides on the opposite side of the microwave oven provides higher intensity electric field and higher temperature profile than the positioning of waveguides in the middle of both the front and the backsides of the microwave oven. In addition, the middle backside is the appropriate position for waveguide in which NRG is uniformly dry and not burnt or overheated. However, it is found that there is no direct relationship between the electric field and temperature changes. This research guides to essential aspects of the design of NRG vulcanization to improve the efficiency of microwave and heat delivering along with other heating systems to heat any sorts of material.
Investigations of Stack Ventilation Operations Using An Energy Modelling And The Bas System
Authors: Woradechjumroen D , Tongshoob T.
Published: July 2020

Green buildings have been intensively constructed due to energy crisis and damaged environmental issues. Additionally, a green building focuses on efficient resource utilization and reducing environmental damage. Mechanical designers emphasize solving energy problem issues in large commercial buildings via a stack ventilation application; it can be used to reduce cooling load and mechanical fan power consumptions. However, stack ventilation installation has been problematic due to Thailand climate, because heat is absorbed on the lower floor of a building causing higher temperature than upper floors; this issue obstructs buoyancy force. Without consideration of the concern, mechanical designers may misunderstand stack ventilation operations from its theory. To avoid the issue, this research applies the three software for assuring the performance composing of (1) LoopDA for stack ventilation simulation to acquire different temperatures for buoyancy force; (2) SketchUp for developing a simplified building configuration; and (3) TRNSYS used for full energy modelling with and without stack ventilation. The energy modelling is validated via the existing building automation system (BAS) data in the example building with the accuracy within ±10 %. The verified building model can be further used to test the stack ventilation operations via the potential simulation instead of sensor installations.
Rapid Fabrication of Close-Typed Electrowetting on Dielectric Devices
Authors: Sukthang K , Pengwang E , Tuantranont A , Wechsatol W
Published: July 2020

Electrowetting on Dielectric (EWOD) devices have becomes a common device for manipulating liquid droplets in chemical, electrochemical, disease diagnosis and biomaterial detection processes. EWOD devices are prefect platform for Lab-on-a-Chip devices due to their simplicity with no moving parts and high manoeuvrability precision. In this paper, the rapid fabrication procedure of close-type EWOD devices is proposed. The EWOD electrodes was designed to manipulate droplets as small as 8 microlitre. The experimental test reveals that the droplet velocity increases with the magnitude of applied voltage. The further experiment also confirms the capability of the fabricated EWOD on droplet dispersion, which is common requirement for Lab-on-a-chip applications.
Investigation on Mechanical Properties and Fracture Mechanism of Carbon Fiber and Glass Fiber Composite at Different Curing Temperature
Authors: Lin Ye Htet , Cuaiman T. , Karin P. , Charoenphonphanich C. , Larpsuriyakul P. , Ohtake N.
Published: July 2020

Weight reduction is one of the big challenges in the auto industry. In the aerospace industry, the high modulus of composite material makes weight savings to replace alloys such as aluminium and titanium. It is one way to reduce fuel consumption and reducing emissions in vehicles by using composite. Among them, carbon fiber and glass fiber are the most useful materials in composite to reduce the weight in vehicles not only in the automotive field but also in aircraft, marine, medicine, sport, etc. In this study, hand lay-up (wet lay-up) method is used to fabricate carbon fiber and glass fiber composites with different curing temperature 30°C (the equivalent of room temperature) until it is dry and 80°C for curing 6 hours. The strength of carbon fiber and glass fiber composites were increased over 10% and the hardness of carbon fiber composite was also increased two times at 80°C curing temperature. Furthermore, the fracture mechanism of carbon fiber and glass fiber composites were also observed by using Scanning Electron Microscopy (SEM) image processing method.
Development of On-The-Machine Robotic Mold-Maintenance System by Utilizing Electro Discharge Deposition Technology
Authors: Mutaguchi Takuma , Yanagihara Kiyoshi , Akashi Kouji , Tsuchiya Kensuke
Published: July 2020

Maintenance of mold in a regular schedule has emerged as powerful platforms for quality assurance of the product. One of the greatest challenges is it may cause a dangerous situation for workers in the process of repairing mold using manual operation. This study set out to investigate the usefulness of a robotic system based on the on-the-machine repair of the worn mold without detaching and attaching the mold. Specifically, an electrodeposition applicator for repairing is attached to the hand of the work conveying robot which is installed near the machine tool. This study employed a vertical articulated robot, which is equipped with various sensors. Fundamental electrodeposition experiments were performed using the constructed robot system. The results from the experiments showed the feasibility of the developed system.
The Effect of Particle Shape on Magnetic Field-Induced Rubber-Like Behavior of Ni-Mn-Ga/Silicone Composites
Authors: Sratong-on P. , Chernenko V.A. , Hosoda H.
Published: July 2020

The single crystalline of the prototype Ni-Mn-Ga ferromagnetic shape memory alloy exhibits a huge magnetic field-induced strain of 6% due to the re-orientation of twin variants. Therefore, it is promising as the magneto-driven actuator material. However, the magnetic field or mechanical stress applied along the orthogonal direction is necessary to restore the deformed bulk single crystal into the original shape. In order to avoid an application of the extra fields, the Ni-Mn-Ga particles/polymer composite is an alternative solution supported by the concept of the accumulated stress in a polymer matrix which drives a deformation recovery of the composite during switching off of the magnetic field. The objective of this study is to clarify the effect of embedded particle shape on the deformation recovery of Ni-Mn-Ga particles/silicone composites by using the finite element method (FEM) and to investigate the local stress distribution in a polymer matrix between either spherical or rectangular shape particles pairs, whereby to provide the guidelines for design/optimization of the magneto-strain-active Ni-Mn-Ga particles/polymer composites. The case studies of the simulation are divided into an isolated particle and a pair of particles, the particles being positioned either parallel or perpendicular to the applied magnetic field direction. Particularly, the simulations reveal that in case of 200 µm of the inter-particle distance in the pair of spherical particles aligned perpendicularly to the applied field, the polymer layer between particles generates the compressive recovery stress of -0.32 MPa, which is insufficient to restore the deformation of the embedded Ni-Mn-Ga particles during removal of the magnetic field. By contrast, the strain recovery effect can be achieved for the rectangular particle pairs, generating the stress concentration in a matrix of about -0.5MPa, in a similar condition and arrangement.
Texture Properties of a-2D Granular Mixture of an Angular Particle under Bi-axial Compression
Authors: Binaree Theechalit , Preechawuttipong Itthichai , Azéma Emilien
Published: July 2020

Utilizing Discrete Element Modeling (DEM), we investigate the shear strength properties and microstructure of 2D granular mixture composed of various regular polygonal particles (from triangle to icosagon and disk) under biaxial compression. Three cases were considered: 1) increase of proportion and angularity started from disk (S1); 2) increase of proportion by decreasing the angularity started from triangle (S2); 3) increase of proportion by random angularity started from disk (S3) and polygons (S4). The results show that the shear strength changes with the mean angularity. On the other hand, the packing fraction slightly varies with the mean angularity. At the microscopic scale, the granular texture in term of the force, the contacts transmitted the force higher than the average force (strong force) are oriented in the direction of externally applied loading but they represent only 40% of the total number of contacts. Besides, the tangential contact forces direction tend to be consistent with the maximum shear strength direction.
Yield Parameters for Iron Powder Compaction on Different Particle Size
Authors: Ogawa R , Fujii J , Taniguchi Y
Published: July 2020

Shear failure yield line in Drucker-Prager yield surface for iron powder on different particle size and amount of interparticle lubricant has been estimated. Critical stress state and uniaxial failure stress state have been determined by a single shear test and uniaxial failure test for a green compact. Compaction cap parameter has been estimated by the lateral force measurement test by instrumented die compaction system. By those estimations, materials input parameters for the Drucker-Prager Cap (DPC) model have been determined successfully, and differences in particle size and amount of lubricant can be recognized. Finite element method (FEM) analysis of simple closed-die compaction has been conducted. As a result, the materials input parameters for the DPC model on different powder properties have been successfully identified as the FEM analysis fairly predicts compaction pressure and density distribution on uniaxial compaction.
Structure and mechanical performance for TiAlN films that are grown with a low Al composition
Authors: Huang Hua , Chen Chun-Sheng , Hu Chih-Chung , Lee Lian-Wang , Hsu Chun-Yao
Published: July 2020

An orthogonal array L9 (34) is used with the grey Taguchi design to optimize the performance of TiAlN films that are grown by direct current magnetron co-sputtering, using a low Al concentration. The structure, mechanical performance and the cutting properties of a coated TiAlN tool for which the films are deposited using various parameters are determined. For the optimal deposition conditions, the (111) diffraction peak intensity increases, which demonstrates an improvement in the crystallinity of the TiAlN films. A TiAlN film coated cutter insert is used for the dry milling of a Cr-Mo alloy steel workpiece and it is shown that the tool flank wear decreases and there are fewer surface defects proved. In the confirmation cutting tests the surface roughness is decreased by 26.08% and the flank wear is 16.15% less. The TiAlN films exhibit good mechanical performance, using grey relational analysis, the improvement rate in hardness H is 14.74%, in friction coefficient is 45.88%, in elastic modulus E is 9.56%, in H/E is 9.09% and in H3/E2 is 25.92%.
Phase assemblage and wear resistance of laser-cladding Al0.8FeCoNiCrCu0.5Six high-entropy alloys on aluminum
Authors: Li Yanzhou , Shi Yan
Published: July 2020

Preparing a coating with excellent mechanical properties on aluminum substrates by laser cladding has always been challenging because of the low melting point and high chemical activity of Al. In this study, we designed Al0.8FeCoNiCrCu0.5Six (x = 0, 0.2, 0.3, 0.4, and 0.5) high-entropy alloys (HEAs) as cladding materials. The proposed study aims to exploit the unique high-entropy effect of HEAs to restrict the the formation of hard and brittle intermetallic compounds via the reaction between Al in the substrate and added powders, thereby enhancing the quality of the formed coatings and ultimately improving the surface properties of the Al alloy. Results show that with an increase in the Si content, the structure of the Al0.8CrFeCoNiCu0.5Six coating changes from FCC + BCC1 + BCC2 to BCC1 + BCC2. The hardness of the Al0.8FeCoNiCrCu0.5Six coating first increases and then decreases with an increase in the Si content. The coatings with the highest and lowest hardness were those with compositions of Al0.8FeCoNiCrCu0.5Si0.4 (592HV0.2) and Al0.8FeCoNiCrCu0.5 (412HV0.2), respectively, which is approximately seven and five times greater than that of the substrate, respectively. The effect of Si content on the wear resistance of the coating is the same as its effect on the hardness. The wear rates of coatings with different Si contents range from 1.19 × 10−6 mm3 Nm−1 to 8.99 × 10−7 mm3 Nm−1 and are only 0.34% to 0.25% of the substrate. Obvious, the Al0.8FeCoNiCrCu0.5Six HEAs can be used as coating materials to improve the mechanical properties of an Al alloy surface.
Effects of oxygen content on the ablation/erosion behavior of 4D carbon/carbon composite material
Authors: Zha Bai-lin , Shi Yi-ang , Wang Jin-jin , Su Qing-dong , Jia Xu-dong
Published: July 2020

A self-designed oxygen-kerosene ablation system was employed to test the four-directional braided carbon/carbon (4D C/C)composite material for studying the ablation performance under different oxygen-rich conditions, that is, −5%, 0% and 5%. The morphology of post-test specimens was analyzed via a scanning electron microscope(SEM), and the ablation rates were calculated. The influence principle of oxygen content on the ablation behavior of carbon/carbon composite material was studied, and the mechanism of ablation was also analyzed. Experimental results showed that the oxygen content will mainly affect the thermo-chemical ablation. The maximum mass ablation rate was 0.161 g · s−1 when the oxygen content was 5%, while the minimum was 0.146 g · s−1 when the oxygen content was 0. Within the range, the interstice between the axial fiber bundle and matrix became larger with the increase of oxygen content. In the two-phase flow test, the effect of particle erosion on material damage was much stronger than the change of oxygen content; on the other hand, fiber bundles were broken particles to form fine particles attaching to fracture fibers, which increased the contact area of the oxidation reaction and indirect accelerated thermochemical ablation process, the number of small carbon particles attaching to the surface gradually decreased with the increased of oxygen content.
Skyrmion pinball and directed motion on obstacle arrays
Authors: Vizarim N P , Reichhardt C J O , Venegas P A , Reichhardt C
Published: July 2020

We examine skyrmions interacting with a square array of obstacles under ac drives applied in one or two directions. For a single direction of ac driving, we find that the Magnus force in conjunction with the obstacle interactions can create elliptical skyrmion orbits of increasing size, leading to localized phases, chaotic phases, and translating or ratcheting orbits. Under two ac drives that are out of phase by 90° and applied in two directions, the skyrmions form localized commensurate orbits that encircle an integer number of obstacles, similar to the electron pinball effect observed for electrons in antidot lattices. As a function of ac amplitude, Magnus force strength, and obstacle size, we find that chaotic scattering regimes and directed motion can emerge even in the absence of asymmetry in the substrate. The directed motion follows different symmetry axes of the periodic substrate, and we observe a variety of reversed ratchet effects. The Magnus force in the skyrmion system produces a significantly larger number of directed motion regimes than are exhibited by overdamped systems. We discuss how these results could be used to move skyrmions in a controlled way for possible applications.
Collagen–iron oxide nanoparticle based ferrogel: large reversible magnetostrains with potential for bioactuation
Authors: Jauch Philine , Weidner Andreas , Riedel Stefanie , Wilharm Nils , Dutz Silvio , Mayr Stefan G.
Published: July 2020

Smart materials such as stimuli responsive polymeric hydrogels offer unique possibilities for tissue engineering and regenerative medicine. As, however, most synthetic polymer systems and their degradation products lack complete biocompatibility and biodegradability, this study aims to synthesize a highly magnetic responsive hydrogel, based on the abundant natural biopolymer collagen. As the main component of vertebratal extracellular matrix, it reveals excellent biocompatibility. In combination with incorporated magnetic iron oxide nanoparticles, a novel smart nano-bio-ferrogel can be designed. While retaining its basic biophysical properties and interaction with living cells, this collagen-nanoparticle hydrogel can be compressed to 38% of its original size and recovers to 95% in suitable magnetic fields. Besides the phenomenology of this scenario, the underlying physical scenarios are also discussed within the framework of network models. The observed reversible peak strains as large as 150% open up possibilities for the fields of biomedical actuation, soft robotics and beyond.
Evidence for the Confluence of Cigarette Smoking, Other Substance Use, and Psychosocial and Mental Health in a Sample of Urban Sexual Minority Young Adults: The P18 Cohort Study
Authors: LoSchiavo Caleb , Acuna Nicholas , Halkitis Perry N
Published: July 2020

Background

Sexual minority men (SMM) and transgender women (TW) are more likely to smoke cigarettes than heterosexual and cisgender peers, which may exacerbate existing disparities in mental and psychosocial health and substance use.

Purpose

As few existing studies have examined the confluence of these factors, we sought to examine tobacco use in a diverse sample of SMM and TW and describe its relationship with other substance use and health.

Methods

Data were drawn from a study of syndemic conditions among SMM and TW, which included measures assessing tobacco use, substance use, and mental, psychosocial, and general health.

Results

A majority of the racially/ethnically and socioeconomically diverse sample (n = 665) reported ever smoking a cigarette, and more than half of them were current smokers. Current smoking was associated with more frequent recent substance use and poorer mental, psychosocial, and general health. In multivariable analyses, current smoking was predicted by more frequent substance use and more severe anxiety, when adjusting for demographic, substance use, and health factors.

Conclusions

A syndemic approach to health conditions such as substance use, mental health, and psychosocial burden dictates a framework of interrelation and mutual exacerbation. In doing so, we found that current cigarette use was associated with more frequent alcohol and marijuana use and more severe anxiety, suggesting a confluence of cigarette smoking, other substance use, and mental health burden. We recommend a holistic approach to treating tobacco use in sexual and gender minority populations that addresses both substance use and the myriad psychosocial burdens that sexual and gender minority communities experience.
Person-Specific Contributions of Brain Pathologies to Progressive Parkinsonism in Older Adults
Authors: Buchman Aron S , Yu Lei , Oveisgharan Shahram , Farfel Jose M , Schneider Julie A , Bennett David A
Published: July 2020

Background

Mixed-brain pathologies are the most common cause of progressive parkinsonism in older adults. We tested the hypothesis that the impact of individual pathologies associated with progressive parkinsonism differs among older adults.

Methods

Data were from 1089 decedents who had undergone annual clinical testing and autopsy. Parkinsonism was based on a modified United Parkinson’s Disease Rating Scale. Linear mixed-effects models were employed, to investigate the combinations of 9 pathologies related to progressive parkinsonism. Then we estimated the person-specific contributions of each pathology for progressive parkinsonism.

Results

The average participant showed 3 pathologies. Parkinson’s disease (PD) and 4 cerebrovascular pathologies (macroinfarcts, atherosclerosis, arteriolosclerosis, and cerebral amyloid angiopathy [CAA]), but not Alzheimer’s disease, TDP-43, hippocampal sclerosis, and microinfarcts, were independently associated with progressive parkinsonism. These pathologies accounted for 13% of additional variance of progressive parkinsonism. Thirty-one different combinations of these 5 pathologies were observed to be associated with progressive parkinsonism observed. On average, PD and CAA accounted, respectively, for 66% and 65% of person-specific progression of parkinsonism, while macroinfarcts, atherosclerosis, and arteriolosclerosis accounted for 41%–48%.

Conclusion

There is much greater heterogeneity in the comorbidity and relative impact of individual brain pathologies affecting progressive parkinsonism than previously recognized and this may account in part for its phenotypic heterogeneity in older adults.
Thundercloud Project: Exploring high-energy phenomena in thundercloud and lightning
Authors: Yuasa Takayuki , Wada Yuuki , Enoto Teruaki , Furuta Yoshihiro , Tsuchiya Harufumi , Hisadomi Shohei , Tsuji Yuna , Okuda Kazufumi , Matsumoto Takahiro , Nakazawa Kazuhiro , Makishima Kazuo , Miyake Shoko , Ikkatai Yuko
Published: July 2020

We have designed, developed, and deployed a distributed sensor network to observe high-energy ionizing radiation, primarily gamma rays, from winter thunderclouds and lightning in coastal areas of Japan. Starting in 2015, we have installed a total of more than 15 ground-based detector systems in Ishikawa Prefecture and Niigata Prefecture, and accumulated 551 days of observation time in four winter seasons from late 2015 to early 2019. In this period, our system recorded 51 gamma-ray radiation events from thundercloud and lightning. Highlights of the science results obtained from this unprecedented amount of data include the discovery of photonuclear reaction in lightning which produces neutrons and positrons along with gamma rays, and deeper insights into the life cycle of a particle-acceleration and gamma-ray-emitting region in a thundercloud. The present paper reviews the objective, methodology, and results of our experiment, with an emphasis on its instrumentation.
Trends in the Risk of Cognitive Impairment in the United States, 1996–2014
Authors: Hale Jo Mhairi , Schneider Daniel C. , Gampe Jutta , Mehta Neil K. , Myrskylä Mikko
Published: July 2020

Background:

Accumulating evidence suggests risk of cognitive impairment is declining in high-income countries. Much of this research uses longitudinal surveys in which learning over repeated tests may bias results. We analyze trends in cognitive impairment in the United States, accounting for prior test experience and selective mortality.

Methods:

We use the Health and Retirement Study, a population-based, nationally representative panel dataset and include individuals ages 50 years and older in 1996–2014 (n = 32,784). We measure cognitive impairment and dementia using standard cutpoints of the modified Telephone Interview for Cognitive Status. We estimate logistic regression models for any impairment and dementia over time, adjusting for age, sex, and race/ethnicity, comparing models with and without adjustment for practice effects and education. We examine heterogeneity in trends by age, sex, race/ethnicity, and education.

Results:

Models not controlling for test experience suggest that risk of cognitive impairment and dementia decreased over the study period. Controlling for test experience reverses the trend. In our primary models, prevalence of any cognitive impairment increased for women from 18.7% to 21.2% (annual change 0.7%, 95% confidence interval [CI], 0.1%, 1.3%) and for men from 17.6% to 21.0% (annual change 1.0%, CI, 0.5%, 1.4%). For dementia, women’s annual increase was 1.7% (CI, 0.8%, 2.6%) and men’s 2.0% (CI, 1.0%, 2.9%). If not for education, the increase would have been stronger. Increased risk was particularly rapid for Latinas, the least educated, and older ages.

Conclusions:

Risk of cognitive impairment increased from 1996 to 2014. Uncovering determinants of increasing cognitive impairment risk should become a research priority. See video abstract: http://links.lww.com/EDE/B702.
Effect of Corneal Transplantation on Patient-Reported Outcomes and Potential Predictors: A Systematic Review
Authors: Vreijsen Eline , Elsman Ellen B. M. , van Nispen Ruth M. A. , Nuijts Rudy M. M. A. , van Rens Ger H. M. B.
Published: July 2020

Purpose:

To investigate the effect and potential predictors of corneal transplantation on patient-reported outcomes such as quality of life, visual functioning, and mental health by systematically reviewing the literature.

Methods:

Studies with 1 preoperative and at least 1 postoperative measurement were searched for in relevant literature databases. Methodological quality was assessed using the Quality Assessment Tool for Quantitative Studies, and effect sizes were calculated.

Results:

Of 1445 unique publications, 14 studies, including 15 study designs, were described in 16 publications. Four randomized controlled trials, 1 controlled clinical trial, 1 cohort study, and 1 before–after study (BA) were of good quality; 6 BAs were of moderate quality; and 2 BAs were of weak quality. Patients generally improved 12 months after transplantation on health-related quality of life (effect size between 0.08 and −3.06), vision-related quality of life (−0.67 and −6.65), visual functioning (−0.55 and −0.63), and subjective visual symptoms (−0.31 and −0.86). Patient satisfaction was high (−0.95). Patients improved on depression (−0.31) but remained stable on anxiety (−0.05) 4 months after transplantation. Predictors of positive outcomes were lower preoperative visual acuity and visual functioning, better postoperative visual factors, younger age, and male sex.

Conclusions:

Corneal transplantation showed overall beneficial effects on patient-reported outcomes. Knowledge of these effects and predictors might result in better treatment, more patient-centered care, and more realistic expectations on the part of patients and ophthalmologists. Future studies should focus on not only health- and vision-related quality of life but also mental health and labor participation using longitudinal study designs.
Venous thromboembolism in the hormonal milieu
Authors: Connell Nathan T. , Connors Jean M.
Published: July 2020

Purpose of review

Hormonal therapy is administered for multiple indications including contraception, alleviation of menopausal symptoms, hypogonadism, and more recently, gender-affirming care. Data suggest varying degrees of increased risk for venous thromboembolism (VTE).

Recent findings

While oral progestin only methods do not appear to increase the risk of VTE, an association was seen with injection progestin contraception. Combined oral contraception with low-dose ethinyl estradiol and most types of progestin increased the risk of VTE compared with levonorgestrel-containing oral therapies. While transdermal hormonal contraception has been previously associated with increased VTE, a recently approved levonorgestrel and ethinyl estradiol transdermal patch reported low rates (<0.2%) in a large single-arm open-label study. Women receiving postmenopausal HRT experienced an increased risk of VTE in a dose-dependent manner when using oral hormonal therapy while nonoral methods, such as topical estrogen, did not appear to increase the risk of VTE. Some studies suggest no increased risk of VTE with testosterone therapy, however, a recent case-crossover study suggested higher VTE risk in men on testosterone, particularly men less than age 65 without hypogonadism. Route of administration had no effect on VTE rates. The estimated incidence rate of VTE risk in transgender women receiving estrogen therapy is 2.3 per 1000 person years, but may be imprecise due to heterogeneity in studies included in published meta-analyses. Surgical risk estimates are primarily indirect data drawn from cisgender patients receiving hormone therapy in the perioperative setting.

Hormonal therapy affects VTE risk to varying degrees dependent on specific type of hormone, formulation, and occasionally route of delivery.
Ankle fractures in patients over age 55 years
Authors: Simske Natasha M. , Benedick Alex , Audet Megan A. , Vallier Heather A.
Published: July 2020

Objectives:

To identify predictors of functional outcomes following treatment of ankle fracture in patients 55 years or older.

Setting:

Level 1 Trauma Center.

Patients/participants:

Four hundred twenty-nine patients with torsional ankle fractures (44A-C): 233 patients (54%) were ages 55 to 64, 25% were between the ages 65 and 74; 21% were 75 years or older.

Intervention:

Operative or nonoperative management of ankle fracture.

Main outcome measure:

Early complications were assessed for all patients after minimum of 6 months, and functional outcome scores as assessed by the Foot Function Index (FFI; n = 166, 39%) and Short Musculoskeletal Function Assessment (SMFA; n = 168, 39%) after median 57 months follow-up.

Results:

Surgical management was elected in 67% of patients. Nonoperative management became more common with advancing age and was associated with fewer unplanned operations (12% vs 3%, P < .01) and complications (21% vs 13%, P = .07). African American race was associated with worse pain on the FFI (P = .002) and BMI was associated with worse (higher) scores on all categories of the FFI and SMFA (all P < .05). Diabetes, neuropathy, and mental illness were also predictive of worse scores on various categories of both surveys. Assistive device use or nonambulatory status at the time of injury was associated with worse disability/dysfunction, activity, and mobility scores on both the FFI and SMFA (all P > 15, P < .05). Sex, Hispanic ethnicity, tobacco use, open fracture, dislocation, fracture pattern, and operative management were not independent predictors in this regression model.

Conclusions:

Baseline health and ambulatory capacity at injury were more predictive of outcomes following ankle fracture than were fracture characteristics or type of treatment.
Predicting poor postoperative acute pain outcome in adults: an international, multicentre database analysis of risk factors in 50,005 patients
Authors: Schnabel Alexander , Yahiaoui-Doktor Maryam , Meissner Winfried , Zahn Peter Konrad , Pogatzki-Zahn Esther Miriam
Published: July 2020

Background:

The aim of this study was to determine simple risk factors for severe pain intensity (≥7 points on a numeric rating scale [NRS]), to analyse their relation to other patient-reported outcome measures and to develop a simple prediction model.

Methods:

We used data from 50,005 patients from the PAIN-OUT project. Within a first data set (n = 33,667), relevant risk factors were identified by logistic binary regression analysis, assessed for additional patient-reported outcome measures beyond pain intensity and summed up for developing a simple risk score. Finally, sum of factors was plotted against postoperative pain outcomes within a validation data set (n = 16,338).

Results:

Odds ratios (OR) for the following risk factors were identified: younger age (<54 years, OR: 1.277), preoperative chronic pain at the site of surgery (OR: 1.195), female sex (OR: 1.433), duration of surgery (>90 minutes, OR: 1.308), preoperative opioid intake (OR: 1.250), feeling anxious (OR: 1.239) and feeling helpless due to pain (OR: 1.198), and the country of the recruiting centre (OR: 1.919). Patients with ≥3 risk factors had more severe pain intensity scores, spent a longer time in severe pain, and wished to have received more pain treatment (P < 0.001). A simple risk score was created with 4 risk factors showing a moderate prediction level.

Conclusions:

Patients with ≥3 risk factors are at higher risk for poor postoperative acute pain outcome after surgery. Future studies using this score might show that preventive strategies might decrease pain intensity, pain-related postoperative dysfunction, and the development of chronic pain.
Intravenous Tranexamic Acid in Implant-Based Breast Reconstruction Safely Reduces Hematoma without Thromboembolic Events
Authors: Weissler Jason M. , Banuelos Joseph , Jacobson Steven R. , Manrique Oscar J. , Nguyen Minh-Doan T. , Harless Christin A. , Tran Nho V. , Martinez-Jorge Jorys
Published: July 2020

Background:

Antifibrinolytic medications, such as tranexamic acid, have recently garnered increased attention. Despite its ability to mitigate intraoperative blood loss and need for blood transfusion, there remains a paucity of research in breast reconstruction. The authors investigate whether intravenous tranexamic acid safely reduces the risk of hematoma following implant-based breast reconstruction.

Methods:

A single-center retrospective cohort study was performed to analyze all consecutive patients undergoing immediate two-stage implant-based breast reconstruction following mastectomy between 2015 and 2016. The incidence of postoperative hematomas and thromboembolic events among all patients was reviewed. The patients in the intervention group received 1000 mg of intravenous tranexamic acid before mastectomy incision and 1000 mg at the conclusion of the procedure. Fisher’s exact test and the Mann-Whitney-Wilcoxon test were used. Multivariate logistic regression models were performed to study the impact of intravenous tranexamic acid after adjusting for possible confounders.

Results:

A total of 868 consecutive breast reconstructions (499 women) were reviewed. Overall, 116 patients (217 breasts) received intravenous tranexamic acid, whereas 383 patients (651 breasts) did not. Patient characteristics and comorbidities were similar between the two the groups. Patients who received tranexamic acid were less likely to develop hematomas [n = 1 (0.46 percent)] than patients who did not [n = 19 (2.9 percent)] after controlling for age, hypertension, and type of reconstruction (prepectoral and subpectoral) (p = 0.018). Adverse effects of intravenous tranexamic acid, including thromboembolic phenomena were not observed. Multivariate analysis demonstrated that age and hypertension independently increase risk for hematoma.

Conclusions:

Intravenous tranexamic acid safely reduces risk of hematoma in implant-based breast reconstruction. Further prospective randomized studies are warranted to further corroborate these findings.

CLINICAL QUESTION/LEVEL OF EVIDENCE:

Therapeutic, III.
Cosmetic Surgery Safety: Putting the Scientific Data into Perspective
Authors: Rohrich Rod J. , Avashia Yash J. , Savetsky Ira L.
Published: July 2020

Optimizing patient safety and outcomes remains at the forefront of cosmetic surgery today. The five most commonly performed procedures are breast augmentation, liposuction, rhinoplasty, blepharoplasty, and abdominoplasty. Safety of all cosmetic surgery is a necessity for its successful, continued practice. This article seeks to elucidate the current literature detailing the major and minor complication profiles of the five most practiced areas in cosmetic surgery.
Trigger Finger Treatment: Identifying Predictors of Nonadherence and Cost
Authors: Nasser Jacob S. , Speth Kelly A. , Billig Jessica I. , Wang Lu , Chung Kevin C.
Published: July 2020

Background:

Evidence-based practices in medicine are linked with a higher quality of care and lower health care cost. For trigger finger, identifying patient factors associated with nonadherence to evidence-based practices will aid physicians in treatment decisions. The objectives were to (1) determine patient factors associated with treatment nonadherence, (2) examine the success rates of steroid injections, and (3) evaluate the economic consequences of nonadherence to treatment recommendations.

Methods:

The authors used data from the Clinformatics DataMart database from 2010 to 2017 to conduct a population-based analysis of patients with single-digit trigger finger. The authors calculated rates of steroid injection success and examined associations between injection success and patient factors using chi-square tests. In addition, the authors analyzed differences in the cost to the insurer, the cost to the patient, and total cost.

Results:

A total of 29,722 patients were included in this analysis. Injection success rates were similar for diabetic (72 percent) and nondiabetic patients (73 percent), women (73 percent), and men (73 percent). Nonetheless, diabetics (OR, 1.4; 95 percent CI, 1.4 to 1.5; p < 0.001) and women (OR, 1.2; 95 percent CI, 1.1 to 1.2; p < 0.001) were significantly more likely to receive nonadherent treatment. In total, $23 million (U.S. dollars) were spent on nonadherent trigger finger care.

Conclusions:

Diabetics and women have increased odds of having surgery without a prior steroid injection, despite similar success rates of steroid injections compared to nondiabetics and men. Because performing surgical release before any steroid injections may represent a higher cost treatment option, providers should provide steroid injections before surgery for all patients regardless of diabetes status or sex to minimize overtreatment.

CLINICAL QUESTION/LEVEL OF EVIDENCE:

Risk, III.
Low-Dose Computed Tomographic Scans for Postoperative Evaluation of Craniomaxillofacial Fractures: A Pilot Clinical Study
Authors: Elegbede Adekunle , Diaconu Silviu , Dreizin David , Li Guang , Dunlow Ryan , Ngaage Ledibabari M. , Rasko Yvonne , Liang Fan , Grant Michael P. , Nam Arthur J.
Published: July 2020

Computed tomographic scans are frequently obtained following craniomaxillofacial fracture reconstruction. The additive radiation from such scans is not trivial; cumulative radiation exposure poses stochastic health risks. In this article, the authors postulate that a low-dose computed tomography protocol provides adequate image quality for postoperative evaluation of reconstructed craniomaxillofacial fractures. This study included patients for whom a computed tomographic scan was indicated following craniomaxillofacial fracture repair at a Level I trauma center. Postoperative craniomaxillofacial computed tomography was performed using a low-dose protocol, rather than standard protocols. A craniomaxillofacial surgeon and a radiologist interpreted the images to determine whether they were of sufficient quality. It was decided a priori that any inadequate low-dose computed tomography would require repeated scanning using standard protocols. The primary endpoint was the need for repeated computed tomography. In addition, the clarity of clinically significant anatomical landmarks on the images was graded on a five-point Likert scale. Twenty patients were scanned postoperatively using the low-dose protocol. Mean radiation dose (total dose-length product) from the low-dose protocol was 71 mGy · cm versus 532 mGy · cm for the preoperative computed tomographic scans that were obtained using conventional protocols (p < 0.001). All 20 low-dose computed tomographic scans were determined to provide satisfactory image quality. No patients required repeated computed tomography secondary to poor image quality. Low-dose computed tomography received high image-quality scores. A low-dose computed tomography protocol that delivers approximately 7.5-fold less radiation than the standard protocols was found to be adequate for postoperative evaluation of craniomaxillofacial fractures. Larger prospective studies may be warranted.

CLINICAL QUESTION/LEVEL OF EVIDENCE:

Therapeutic, IV.
Abdominoplasty with Scarpa Fascia Preservation: Randomized Controlled Trial with Assessment of Scar Quality and Cutaneous Sensibility
Authors: Novais Catarina S. , Carvalho Jorge , Valença-Filipe Rita , Rebelo Marco , Peres Helena , Costa-Ferreira António
Published: July 2020

Background:

Scarpa fascia preservation during abdominoplasty has been shown to reduce complications associated with the traditional technique. As an extension of a previously published randomized controlled trial, this study aims to clarify whether preservation of Scarpa fascia during abdominoplasty has an influence on scar quality or sensibility recovery.

Methods:

This was a single-center clinical trial, involving 160 patients randomly assigned to one of two surgical procedures: classic full abdominoplasty (group A) and abdominoplasty with preservation of Scarpa fascia (group B). Patients were later convoked to assess scar quality and abdominal cutaneous sensibility. Scar quality was evaluated through the Patient and Observer Scar Assessment Scale. Cutaneous sensibility was measured on the upper and lower abdomen, using light touch, Semmes-Weinstein testing (5.07/10-g monofilament), and a 25-gauge needle.

Results:

A total of 99 patients (group A, 54 patients; group B, 45 patients) responded to contact, with a mean follow-up time of 44 months. Concerning scar quality, Patient and Observer Scar Assessment Scale scores were similar between groups. On the upper abdomen, there was a statistically significant difference between groups on cutaneous sensibility, on the examination with the Semmes-Weinstein 5.07/10-g monofilament (group A, 79.6 percent; group B, 93.3 percent; p = 0.046) and pain (group A, 90.7 percent; group B, 100 percent; p = 0.044). No statistically significant differences were found between groups on the lower abdomen. A considerable proportion of patients (two-thirds) still presented sensibility alterations in the subumbilical area 3½ years after abdominoplasty.

Conclusion:

Scarpa fascia preservation during abdominoplasty does not influence scar quality, but it improves sensibility recovery in the supraumbilical area.

CLINICAL QUESTION/LEVEL OF EVIDENCE:

Therapeutic, II.
Bringing Palliative Care Downstairs
Authors: Berta Mara , Leon Anne , Silvey Katherine
Published: July 2020

Although the emergency department (ED) may not be traditionally thought of as the ideal setting for the initiation of palliative care, it is the place where patients most frequently seek urgent care for recurrent issues such as pain crisis. Even if the patients' goals of care are nonaggressive, their caregivers may bring them to the ED because of their own distress at witnessing the patients' suffering. Emergency department providers, who are trained to focus on the stabilization of acute medical crises, may find themselves frustrated with repeat visits by patients with chronic problems. Therefore, it is important for ED providers to be comfortable discussing goals of care, to be adept at symptom management for chronic conditions, and to involve palliative care consultants in the ED course when appropriate. Nurse practitioners, with training rooted in the holistic tradition of nursing, may be uniquely suited to lead this shift in the practice paradigm. This article presents case vignettes of 4 commonly encountered ED patient types to examine how palliative care principles might be applied in the ED.
Proper Placement of Tubes on Chest Radiographs
Authors: Ramponi Denise R. , Callahan Allison
Published: July 2020

A variety of tubes are placed by the advanced practice provider including endotracheal tubes, nasogastric tubes, feeding tubes, and chest tubes. Recognizing the proper placement of these tubes is critical to prevent complications and allow for intended use including ventilation, nasogastric drainage, providing enteral nutrition, and drainage of air or fluid from the pleural space. The advanced practice provider must be aware of the anatomical landmarks that help indicate correct positioning for safe use and proper functioning of these tubes. This article will discuss how to assess for proper placement of endotracheal, nasogastric, and chest tubes.
Preventing Cauliflower Ear
Authors: Gooch Michael D.
Published: July 2020

Traumatic auricular hematomas may be encountered in emergency care settings due to blunt trauma such as assaults or contact sports. Emergency nurse practitioners should be able to recognize and treat this injury to prevent complications. Treatment usually consists of evacuation of the hematoma by aspiration or incision and drainage using local or regional anesthesia, followed by the application of a pressure dressing or suturing. Without proper evacuation and steps to prevent reaccumulation, tissue necrosis and deformity (i.e., cauliflower ear) may occur.