bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Sand Production in an Unconsolidated Sandstone Reservoir in a Deepwater Gas Field
Authors: Deng Fucheng , Yan Chuanliang , Jia Shanpo , Chen Shenghong , Wang Lihua , He Liang
Published: March 2019

In an unconsolidated sandstone reservoir of a deepwater gas field, due to the reduction of the rock compaction by deepwater, sand production is more likely to occur in the reservoir during production under certain production pressure differences. Therefore, it is important to accurately control the production pressure difference. A theoretical analysis model of sand production was established. On the basis of the model, the critical production pressure difference and the critical flow rate of the sand production were tested through indoor simulated experiments of sand production of three-dimensional full-diameter core. In addition, the critical production pressure difference for the sand production with an open hole completion was verified by means of numerical analysis. The analysis procedures and results are as follows: (1) based on the production test, the gas flow rate and the sand production rate under various production pressure differences were measured. It was found that the critical production pressure difference of core of target block was about 2 MPa, which is lower than the critical sand production pressure difference of core in shallow water or land. (2) A finite element analysis model was established by means of a theoretical analysis on the basis of core mechanics testing, and the analytical model was validated by comparing the experimental model and the theoretical model. A plastic deformation criterion for sand production was proposed. (3) The sand production model of the deepwater reservoir was established based on field parameters. The primary parameters that affect the rock strength were analyzed using the sand production criterion, which was verified by the experimental and numerical simulation results. Analysis results show that the effect of cohesive compared with elastic modulus, Poisson's ratio, and angle of internal friction on sand production is greater. At the same time, it should also pay attention to the influence of the drilling and production process on sand production.
Efficiency Enhancement of Photovoltaic/Thermal Module Using Front Surface Cooling Technique in Winter and Summer Seasons: An Experimental Investigation
Authors: Sainthiya Himanshu , Beniwal Narendra S.
Published: March 2019

This paper presents the effect of the front surface water cooling on performance parameters (solar cell temperature, back surface temperature, outlet water temperature, electrical efficiency, overall efficiency, etc.) of photovoltaic/thermal (PV/T) module in both winter and summer seasons in Indian climatic conditions. A mathematical model of PV/T module considering energy balance equations has also been presented. A comparative analysis of performance parameters obtained analytically and experimentally has also been presented. A fair agreement has also been found between analytical and experimental results which is supported by correlation coefficient of approximately unity and root mean square error of 10–14%. By front surface water cooling, solar cell and back surface temperature of PV/T module have been found to decrease considerably which in turn resulted in enhanced electrical and overall efficiency of module in winter and summer seasons.
Predictive Erosion Model for Mixed Flow Centrifugal Pump
Authors: Pirouzpanah Sahand , Patil Abhay , Chen Yiming , Morrison Gerald
Published: March 2019

Electrical submersible pumps (ESPs) are widely used in upstream oil production. The presence of a low concentration solid phase, particle-laden flow, in the production fluid may cause severe damage in the internal sections of the pump which reduces its operating lifetime. To better understand the ESP pump's endurance, two different designs of commonly used mixed flow ESPs were studied numerically to determine the pump's flow behavior at its best efficiency point. Computational fluid dynamics (CFD) analysis was conducted on two stages of one design type of pump's primary flow path employing Eulerian–Granular scheme in ANSYS FLUENT. The key parameters affecting the erosion phenomena within the pump such as turbulence kinetic energy, local sand concentration, and near wall relative sand velocity were identified. The predictive erosion model applicable to pumps was developed by correlating the erosion key parameters with available experimental results. It is concluded that the use of an erosion model on the second design of ESP proves the model's versatility to predict the erosion on different designs of ESPs.
Directional Motion of a Graphene Sheet on Graded MoS2–WSe2 Lateral Heterostructures
Authors: Han Guang-Rong , Chang Tienchong , Jiang Jin-Wu
Published: March 2019

Directional motion is one of the most fundamental motions in the nature, which is driven by specific types of gradients. The transition metal dichalcogenides graded lateral heterostructure is a valuable semiconductor playing crucial roles in electronic and optoelectronic devices. This lateral heterostructure has a graded composition and is thus a promising candidate to drive possible directional motions. Here, we perform molecular dynamics simulations to demonstrate the directional motion of a graphene sheet on top of the MoS2–WSe2 graded lateral heterostructure. It is quite interesting that the direction for the diffusion is sensitive to the graphene sheet’s initial location, which is in two different regions. The graphene sheet diffuses in opposite directions for the initial location that falls in different regions. We derive an analytic formula for the interlayer coupling potential, which discloses the underlying mechanism for the dependence of the directional motion on the initial location of the graphene sheet. These results shall be varifiable by present experimental set ups and may be valuable for the application of the transition metal dichalcogenides graded lateral heterostructure in practical electronic devices.
On Planar Impacts of Cylinders and Balls
Authors: Alluhydan Khalid , Razzaghi Pouria , Hurmuzlu Yildirim
Published: March 2019

In this paper, we studied planar collisions of balls and cylinders with an emphasis on the coefficient of restitution (COR). We conducted a set of experiments using three types of materials: steel, wood, and rubber. Then, we estimated the kinematic COR for all collision pairs. We discovered unusual variations among the ball–ball (B–B) and ball–cylinder (B–C) CORs. We proposed a discretization method to investigate the cause of the variations in the COR. Three types of local contact models were used for the simulation: rigid body, bimodal linear, and bimodal Hertz models.

Based on simulation results, we discovered that the bimodal Hertz model produced collision outcomes that had the greatest agreement with the experimental results. In addition, our simulations showed that softer materials need to be segmented more than harder ones. Softer materials are materials with smaller collision stiffness values than harder ones. Moreover, we obtained a relationship between the collision stiffness ratio and the number of segments of softer materials to produce physically accurate simulations of B–C CORs. We validated this relationship and the proposed method by conducting two additional sets of experiments.
Energy-Based Strength Theory for Soft Elastic Membranes
Authors: Pourmodheji Reza , Qu Shaoxing , Yu Honghui
Published: March 2019

In the previous studies by the authors and others, it was demonstrated that there are two possible defect growth modes and a characteristic material length for any soft material. For a pre-existing defect smaller than the material characteristic length, the energy is dissipated all around the defect as it grows and the critical load for the growth is independent of the defect size. For defects larger than the characteristic length, the growth is by cracking and the energy is dissipated along a plane. Thus, the critical load for the growth is size dependent and can be predicted by fracture mechanics. In this study, we apply the same energy-based argument to the failure of thin membranes, with the focus on the first growth mode that gives the maximum critical load. We assume that strain localization due to damage is the precursor to rupture, and hence, we model the corresponding zone as a through-thickness hole, with its size smaller than the material characteristic length. The defect grows when the elastic energy relaxed by the growth is enough to provide the energy needed for internal microstructure changes. This leads us to the size-independent failure conditions for membranes under the biaxial load. The conditions are expressed in terms of either two principal stretches or two principal stresses for two different types of materials. For verification, we test the theory using the published experimental data on natural and styrene-butadiene rubber. By using the experimental data from equal biaxial loading, we predict the critical principal stretch ratios and critical stresses for different biaxialities. The predictions agree well with the experimental results.
Acoustic radiation forces on three-layered drug particles in focused Gaussian beams
Authors: Jiang Zhong-Qiu , Wang Yuan-Yuan , Yao Jie , Wu Da-Jian , Liu Xiao-Jun
Published: March 2019

Drug delivery by acoustic waves is a crucial technology for targeted therapy. Recently, a three-layered drug micro-particle was proposed and fabricated, the second shell of which greatly improves both the encapsulation of the drug and the flexibility in its release rate. In this work, the acoustic radiation force (ARF) of an acoustic focused Gaussian beam on a three-layered particle comprising an inner drug core (D), a middle layer of poly(lactide-co-glycolide) (PLGA), and an outer chitosan shell (CS) is investigated. A three-layered elastic shell (TES) mimics the D–PLGA–CS structure, and the acoustic scattering from and ARF of the D–PLGA–CS are studied using Mie theory. This paper focuses on how the geometry and acoustic parameters of the outer shell influence the ARF, finding that the Poisson's ratio of the outer shell affects the ARF more than does the density or Young's modulus. In addition, this paper finds that the choice of the inner drug has little effect on the ARF acting on the D–PLGA–CS particle. The present work may benefit the acoustic manipulation of both TESs and three-layered drugs.
Development of an On-Water Graded Exercise Test for Flat-Water Sprint Kayak Athletes
Authors: Winchcombe Chelsie E. , Binnie Martyn J. , Doyle Matthew M. , Hogan Cruz , Peeling Peter
Published: March 2019

Purpose: To determine the reliability and validity of a power-prescribed on-water (OW) graded exercise test (GXT) for flat-water sprint kayak athletes. Methods: Nine well-trained sprint kayak athletes performed 3 GXTs in a repeated-measures design. The initial GXT was performed on a stationary kayak ergometer in the laboratory (LAB). The subsequent 2 GXTs were performed OW (OW1 and OW2) in an individual kayak. Power output (PWR), stroke rate, blood lactate, heart rate, oxygen consumption, and rating of perceived exertion were measured throughout each test. Results: Both PWR and oxygen consumption showed excellent test–retest reliability between OW1 and OW2 for all 7 stages (intraclass correlation coefficient > .90). The mean results from the 2 OW GXTs (OWAVE) were then compared with LAB, and no differences in oxygen consumption across stages were evident (P ≥ .159). PWR was higher for OWAVE than for LAB in all stages (P ≤ .021) except stage 7 (P = .070). Conversely, stroke rate was lower for OWAVE than for LAB in all stages (P < .010) except stage 2 (P = .120). Conclusions: The OW GXT appears to be a reliable test in well-trained sprint kayak athletes. Given the differences in PWR and stroke rate between the LAB and OW tests, an OW GXT may provide more specific outcomes for OW training.
Effects of Playing Surface on Physical, Physiological, and Perceptual Responses to a Repeated-Sprint Ability Test: Natural Grass Versus Artificial Turf
Authors: Ammar Achraf , Bailey Stephen J. , Hammouda Omar , Trabelsi Khaled , Merzigui Nabil , El Abed Kais , Driss Tarak , Hökelmann Anita , Ayadi Fatma , Chtourou Hamdi , Gharbi Adnen , Turki Mouna
Published: March 2019

Purpose:The effect of playing surface on physical performance during a repeated-sprint ability (RSA) test and the mechanisms for any potential playing-surface-dependent effects on RSA performance are equivocal. The purpose of this study was to investigate the effect of natural grass (NG) and artificial turf (AT) on physical performance, ratings of perceived exertion, feeling scale, and blood biomarkers related to anaerobic contribution (blood lactate [Lac]), muscle damage (creatine kinase and lactate dehydrogenase), inflammation (C-reactive protein), and immune function (neutrophils [NEU], lymphocytes [LYM], and monocytes) in response to an RSA test.Methods:A total of 9 male professional football players from the same regional team completed 2 sessions of RSA testing (6 × 30 s interspersed with a 35-s recovery) on NG and AT in a randomized order. During the RSA test, total (sum of distances) and peak (highest distance covered in a single repetition) distance covered were determined using a measuring tape, and the decrement in sprinting performance from the first to the last repetition was calculated. Before and after the RSA test, ratings of perceived exertion, feeling scale, and Lac, creatine kinase, lactate dehydrogenase, C-reactive protein, NEU, LYM, and monocytes were recorded in both NG and AT conditions.Results:Although physical performance declined during the RSA blocks on both surfaces (P = .001), the distance covered declined more on NG (15%) than on AT (11%;P = .04; effect size [ES] = −0.34; 95% confidence interval [CI], −1.21 to 0.56) with a higher total distance covered (+6% [2%]) on AT (P = .018; ES = 1.15; 95% CI, 0.16 to 2.04). In addition, lower ratings of perceived exertion (P = .04; ES = −0.49; 95% CI, −1.36 to 0.42), Lac, NEU, and LYM (P = .03; ES = −0.80; 95% CI, −1.67 to 0.14; ES = −0.16; 95% CI, −1.03 to 0.72; and ES = −0.94; 95% CI, −1.82 to 0.02, respectively) and more positive feelings (P = .02; ES = 0.81; 95% CI, −0.13 to 1.69) were observed after the RSA test performed on AT than on NG. No differences were observed in the remaining physical and blood markers.Conclusion:These findings suggest that RSA performance is enhanced on AT compared with NG. This effect was accompanied by lower fatigue perception and Lac, NEU, and LYM and a more pleasurable feeling. These observations might have implications for physical performance in intermittent team-sport athletes who train and compete on different playing surfaces.
Alternate-Day Low Energy Availability During Spring Classics in Professional Cyclists
Authors: Heikura Ida A. , Quod Marc , Strobel Nicki , Palfreeman Roger , Civil Rita , Burke Louise M.
Published: March 2019

Purpose: To assess energy and carbohydrate (CHO) availability and changes in blood hormones in 6 professional male cyclists over multiple single-day races. Methods: The authors collected weighed-food records, power-meter data, and morning body mass measurements across 8 d. CHO intakes were compared with contemporary guidelines. Energy availability (EA) was calculated as energy intake minus exercise energy expenditure, relative to fat-free mass (FFM). Skinfold thickness and blood metabolic and reproductive hormones were measured prestudy and poststudy. Statistical significance was defined as P ≤ .05. Results: Body mass (P = .11) or skinfold thickness (P = .75) did not change across time, despite alternate-day low EA (14 [9] vs 57 [10] kcal·kg−1 FFM·d−1, race vs rest days, respectively; P < .001). Cyclists with extremely low EA on race days (<10 kcal·kg−1 FFM·d−1; n = 2) experienced a trend toward decreased testosterone (−14%) and insulin-like growth factor 1 (−25%), despite being high EA (>46 kcal·kg−1 FFM·d−1) on days between. CHO intakes were significantly higher on race versus rest days (10.7 [1.3] vs 6.4 [0.8] g·kg−1·d−1, respectively; P < .001). The cyclists reached contemporary prerace fueling targets (3.4 [0.7] g·kg−1·3 h−1 CHO; P = .24), while the execution of CHO guidelines during race (51 [9] g·h−1; P = .048) and within acute (1.6 [0.5] g·kg−1·3 h−1; P = .002) and prolonged (7.4 [1.0] g·kg−1·24 h−1; P = .002) postrace recovery was poor. Conclusions: The authors are the first to report the day-by-day periodization of energy and CHO in a small sample of professional cyclists. They also examined the logistics of conducting a field study under stressful conditions in which major cooperation from the subjects and team management is needed. Their commentary around these challenges and possible solutions is a major novelty of the article.
Muscle Activation Patterns Correlate With Race Walking Economy in Elite Race Walkers: A Waveform Analysis
Authors: Gomez-Ezeiza Josu , Santos-Concejero Jordan , Torres-Unda Jon , Hanley Brian , Tam Nicholas
Published: March 2019

Purpose: To analyze the association between muscle activation patterns on oxygen cost of transport in elite race walkers over the entire gait waveform. Methods: A total of 21 Olympic race walkers performed overground walking trials at 14 km·h−1 where muscle activity of the gluteus maximus, adductor magnus, rectus femoris, biceps femoris, medial gastrocnemius, and tibialis anterior were recorded. Race walking economy was determined by performing an incremental treadmill test ending at 14 km·h−1. Results: This study found that more-economical race walkers exhibit greater gluteus maximus (P = .022, r = .716), biceps femoris (P = .011, r = .801), and medial gastrocnemius (P = .041, r = .662) activation prior to initial contact and weight acceptance. In addition, during the propulsive and the early swing phase, race walkers with higher activation of the rectus femoris (P = .021, r = .798) exhibited better race walking economy. Conclusions: This study suggests that the neuromuscular system is optimally coordinated through varying muscle activation to reduce the metabolic demand of race walking. These findings highlight the importance of proximal posterior muscle activation during initial contact and hip-flexor activation during early swing phase, which are associated with efficient energy transfer. Practically, race walking coaches may find this information useful in the development of specific training strategies on technique.
Development and Validation of a Monitoring Instrument for Sport Psychology Practice: The Sport Psychology Outcomes and Research Tool (SPORT)
Authors: Hansen Ashley A. , Perry Joanne E. , Lace John W. , Merz Zachary C. , Montgomery Taylor L. , Ross Michael J.
Published: March 2019

Evidence for the mechanisms of change by which sport psychology interventions enhance performance is limited and treatment monitoring and outcomes measures would assist in establishing evidence-based practices. The present paper fills a gap in sport psychology literature by demonstrating the development and validation of a new measure (Sport Psychology Outcomes and Research Tool; SPORT). Study 1 described test construction and pilot item selection with 73 collegiate student-athletes. Twenty-three pilot items contributed unique variance while maintaining the original constructs and were selected from 80 initial items. In Study 2, exploratory and confirmatory factor analyses were conducted with collegiate student-athletes (n = 220), revealing a 17-item, four-factor model measuring Athlete Wellbeing, Self-Regulation, Performance Satisfaction, and Sport-Related Distress. Concurrent validity was supported through correlational analyses. Overall, results supported the SPORT as a new transtheoretical tool for monitoring effectiveness and outcomes of sport psychology interventions.
Acute Effects of Pectoralis Minor Self-Mobilization on Shoulder Motion and Posture: A Blinded and Randomized Placebo-Controlled Study in Asymptomatic Individuals
Authors: Laudner Kevin , Thorson Kyle
Published: March 2019

Context: Tightness of the pectoralis minor is a common characteristic that has been associated with aberrant posture and shoulder pathology. Determining conservative treatment techniques for maintaining and lengthening this muscle is critical. Although some gross stretching techniques have been proven effective, there are currently no empirical data regarding the effectiveness of self-myofascial release for treating tightness of this muscle. Objective: To determine the acute effectiveness of a self-myofascial release with movement technique of the pectoralis minor for improving shoulder motion and posture among asymptomatic individuals. Design: Randomized controlled trial. Setting: Orthopedic rehabilitation clinic. Participants: A total of 21 physically active, college-aged individuals without shoulder pain volunteered to participate in this study. Main Outcome Measures: Glenohumeral internal rotation, external rotation, and flexion range of motion (ROM), pectoralis minor length, and forward scapular posture were measured in all participants. The intervention group received one application of a self-soft-tissue mobilization of the pectoralis minor with movement. The placebo group completed the same motions as the intervention group, but with minimal pressure applied to the xiphoid process. Separate analyses of covariance were used to determine differences between groups (P < .05). Results: Separate analyses of covariance showed that the self-mobilization group had significantly more flexion ROM, pectoralis minor length, and less forward scapular posture posttest than the placebo group. However, the difference in forward scapular posture may not be clinically significant. No differences were found between groups for external or internal rotation ROM. Conclusions: The results of this study indicate that an acute self-myofascial release with movement is effective for improving glenohumeral flexion ROM and pectoralis minor length, and may assist with forward scapular posture. Clinicians should consider this self-mobilization in the prevention and rehabilitation of pathologies associated with shortness of the pectoralis minor.
Adaptation of Tendon Structure and Function in Tendinopathy With Exercise and Its Relationship to Clinical Outcome
Authors: Färnqvist Kenneth , Pearson Stephen , Malliaras Peter
Published: March 2019

Context:Exercise is seen as the most evidence-based treatment for managing tendinopathy and although the type of exercise used to manage tendinopathy may induce adaptation in healthy tendons, it is not clear whether these adaptations occur in tendinopathy and if so whether they are associated with improved clinical outcomes.Objective:The aim of the study was to synthesize available evidence for adaptation of the Achilles tendon to eccentric exercise and the relationship between adaptation (change in tendon thickness) and clinical outcomes among people with Achilles tendinopathy.Evidence Acquisition:The search was performed in September 2018 in several databases. Studies investigating the response (clinical outcome and imaging on ultrasound/magnetic resonance imaging) of pathological tendons (tendinopathy, tendinosis, and partial rupture) to at least 12 weeks of eccentric exercise were included. Multiple studies that investigated the same interventions and outcome were pooled and presented in effect size estimates, mean difference, and 95% confidence intervals if measurement scales were the same, or standard mean difference and 95% confidence intervals if measurements scales were different. Where data could not be pooled the studies were qualitatively synthesized based on van Tulder et al.Evidence Synthesis:Eight studies met the inclusion and exclusion criteria and were included in the review. There was strong evidence that Achilles tendon thickness does not decrease in parallel with improved clinical outcomes.Conclusions:Whether a longer time to follow-up is more important than the intervention (ie, just the time per se) for a change in tendon thickness remains unknown. Future studies should investigate whether exercise (or other treatments) can be tailored to optimize tendon adaptation and function, and whether this relates to clinical outcomes.
Psychometric Properties of the iHandy Level Smartphone Application for Measuring Lumbar Spine Range of Motion and Lordosis: A Systematic Review of the Literature
Authors: Pourahmadi Mohammadreza , Hesarikia Hamid , Ghanjal Ali , Shamsoddini Alireza
Published: March 2019

Context: Advent of smartphones has brought a wide range of clinical measurement applications (apps) within the reach of most clinicians. The vast majority of smartphones have numerous built-in sensors such as magnetometers, accelerometers, and gyroscopes that make the phone capable of measuring joint range of motion (ROM) and detecting joint positions. The iHandy Level app is a free app which has a visual display alike with the digital inclinometer in regard to numeric size. Objective: The purpose of this systematic review was to evaluate available evidence in the literature to assess the psychometric properties (ie, reliability and validity) of the iHandy Level app in measuring lumbar spine ROM and lordosis. Methods: PubMed/MEDLINE, Scopus, Ovid, Google Scholar, and ScienceDirect were searched from inception to September 2018 for single-group repeated-measures studies reporting outcomes of lumbar spine ROM or lordosis in adult individuals without symptoms of low back pain (LBP) or patients with LBP. The quality of each included study was assessed using the Quality Appraisal of Reliability Studies checklist. Results: A total of 4 studies with 273 participants were included. Two studies focused on measuring active lumbar spine ROM, and 2 studies evaluated lumbar spine lordosis. Three studies included asymptomatic subjects, and one study recruited patients with LBP. The results showed that the iHandy Level app has sufficient psychometric properties for measuring standing thoraco-lumbo-sacral flexion, extension, lateral flexion, isolated lumbar spine flexion ROM, and lumbar spine lordosis in asymptomatic subjects. One study reported poor concurrent validity with a bubble inclinometer (r = .19–.53), poor intrarater reliability (intraclass correlation coefficient = .19–.39), and poor to good interrater reliability (intraclass correlation coefficient = .24–.72) for the measurement of active lumbar spine ROM using the iHandy Level app in patients with LBP. Conclusions: This review provided a valuable summary of the research to date examining the psychometric properties of the iHandy Level app for measuring lumbar spine ROM and lordosis.
Linking Mn
2+
, α-synuclein, and neuroinflammation
Authors: Ferrarelli Leslie K.
Published: March 2019

Several studies elucidate the molecular links between manganese exposure and Parkinson’s disease.
In Vivo
Models of Oncoproteins Encoded by Kaposi’s Sarcoma-Associated Herpesvirus
Authors: Bravo Cruz Ariana G. , Damania Blossom
Published: March 2019

Kaposi’s sarcoma-associated herpesvirus (KSHV) is a human oncogenic virus. KSHV utilizes its proteins to modify the cellular environment to promote viral replication and persistence.
Spatial and Temporal Analysis of the Stomach and Small-Intestinal Microbiota in Fasted Healthy Humans
Authors: Seekatz Anna M. , Schnizlein Matthew K. , Koenigsknecht Mark J. , Baker Jason R. , Hasler William L. , Bleske Barry E. , Young Vincent B. , Sun Duxin
Published: March 2019

The gut microbiota are linked to a variety of gastrointestinal diseases, including inflammatory bowel disease. Despite this importance, microbiota dynamics in the upper gastrointestinal tract are understudied. Our article seeks to understand what factors impact microbiota dynamics in the healthy human upper gut. We found that the upper gastrointestinal tract contains consistently prevalent bacterial OTUs that dominate the overall community. Microbiota variability is highest in the stomach and duodenum and correlates with pH.
Aggregate Filamentous Growth Responses in Yeast
Authors: Chow Jacky , Dionne Heather M. , Prabhakar Aditi , Mehrotra Amit , Somboonthum Jenn , Gonzalez Beatriz , Edgerton Mira , Cullen Paul J.
Published: March 2019

Filamentous growth is a fungal morphogenetic response that is critical for virulence in some fungal species. Many aspects of filamentous growth remain poorly understood. We have identified an aspect of filamentous growth in the budding yeast
Saccharomyces cerevisiae
and the human pathogen
Candida albicans
where cells behave collectively to invade surfaces in aggregates. These responses may reflect an extension of normal filamentous growth, as they share the same signaling pathways and effector processes. Aggregate responses may involve cooperation among individual cells, because aggregation was stimulated by cell adhesion molecules, secreted enzymes, and diffusible molecules that promote quorum sensing. Our study may provide insights into the genetic basis of collective cellular responses in fungi. The study may have ramifications in fungal pathogenesis, in situations where collective responses occur to promote virulence.
Examinations under anaesthesia as a measure of disease burden in unilateral retinoblastoma: the London experience
Authors: Fabian Ido Didi , Shah Vishal , Kapelushnik Noa , Naeem Zishan , Onadim Zerrin , Price Elizabeth , Chowdhury Tanzina , Duncan Catriona , Stansfield David , Sagoo Mandeep , Reddy Maddy Ashwin
Published: March 2019

Background

Early diagnosis strategies and advances in retinoblastoma (Rb) management have resulted in nearly 100% survival. More attention should, therefore, be given to quality of life considerations. We aimed to quantify the number of examinations under anaesthesia (EUAs) in a cohort of patients with Rb, as a measure of disease burden.

Methods

A retrospective analysis of patients with unilateral Rb that presented to the London Rb service from 2006 to 2013, were treated and had long-term follow-up. Correlations of clinical variables to number of EUAs were investigated.

Results

A total of 107 patients with Rb were included that presented at a mean age of 26.51 ± 22.68 months. The International Intraocular Retinoblastoma Classification (IIRC) was group B in 5 (5%), C in 13 (12%), D in 48 (45%) and E in 41 (38%) of the cases. Primary treatment was intravenous chemotherapy in 36 (34%) and enucleation in 71 (66%) of the cases. Mean number of EUAs was 20.67 ± 6.62, 12.52 ± 6.23 and 11.15 ± 6.91 for combined groups B/C, group D and group E patients (p < 0.001), respectively. On analysis, early age atpresentation and conservative treatments were found to significantly correlate with increased number of EUAs (p < 0.001). Mean follow-up time was 74.42 ± 25.16 months and no metastasis or death were reported.

Conclusion

Families should be counselled regarding the number of EUAs associated with the patient's IIRC group, with B/C eyes undergoing twice the number as compared with D/E eyes. For group D cases, where both enucleation and conservative therapy are valid options, treatment choice has a significant impact on the number of EUAs.
Illnesses during 11 international athletics championships between 2009 and 2017: incidence, characteristics and sex-specific and discipline-specific differences
Authors: Edouard Pascal , Junge Astrid , Sorg Marine , Timpka Toomas , Branco Pedro
Published: March 2019

Background

Illnesses impair athletes’ participation and performance. The epidemiology of illness in athletics is limited.

Objective

To describe the occurrence and characteristics of illnesses during international athletics championships (indoor and outdoor), and to analyse differences with regards to athletes’ sex and participation in explosive and endurance disciplines.

Methods

During 11 international championships held between 2009 and 2017, physicians from both national medical teams and the local organising committees reported daily on all athlete illnesses using a standardised report form. Illness frequencies, incidence proportions (IPs) and rates (IRs), and relative risks (RR) with 95% CIs were calculated.

Results

During the 59 days of the 11 athletics championships, 546 illnesses were recorded in the 12 594 registered athletes equivalent to IP of 43.4 illnesses per 1000 registered athletes (95% CI 39.8 to 46.9) or IR of 1.2 per 1000 registered athlete days (95% CI 1.1 to 1.2). The most frequently reported illnesses were upper respiratory tract infections (18.7%), exercise-induced fatigue/hypotension/collapse (15.4%) and gastroenteritis (13.2%). No myocardial infarction was recorded. A total of 28.8% of illnesses were expected to lead to time loss from sport. The illness IP was similar in male and female athletes, with few differences in illness characteristics. During outdoor championships, the illness IP was higher in endurance than explosive disciplines (RR=1.87; 95% CI 1.58 to 2.23), with a considerably higher IP of exercise-induced illness in endurance disciplines, but a similar upper respiratory tract infection IP in both discipline groups.

Conclusions

Illness prevention strategies during international athletics championships should be focused on the most frequent diagnoses in each discipline group.
Resumption of sexual intercourse post partum and the utilisation of contraceptive methods in China: a cross-sectional study
Authors: Zhuang Caixia , Li Ting , Li Lei
Published: March 2019

Objective

This is a cross-sectional study that aimed to examine the resumption of sexual intercourse post partum, the utilisation of contraceptive methods and the influencing factors among Chinese women at a tertiary teaching hospital.

Design

This is a questionnaire survey by written and online interview for participants.

Participants

Based on medical records, we sent online questionnaires about postpartum sexual intercourse and contraception plans to 550 eligible women.

Main outcome measures

Potential factors affecting postpartum sexual intercourse and utilisation of contraception were determined by analysis of epidemiological and clinical factors and sexual experiences during and after pregnancy.

Results

Of 550 eligible participants, 406 women (73.8%) with a postpartum period of 8.5 months (range 6–10) completed the questionnaires; 146 of 406 (36.0%) resumed sexual intercourse within 3 months, and 259 of 279 (92.8%) used contraceptive methods. In univariate and multivariate analyses, sexual intercourse during pregnancy (adjusted OR 4.4, 95% CI 2.8 to 6.9) and resumption of menstruation (adjusted OR 2.5, 95% CI 1.5 to 4.3) were significant influencing factors in resumption of sexual intercourse within 3 months after childbirth. No factor was found to be associated with using contraceptive methods or the general resumption of sexual intercourse post partum. The questionnaire had good reliability and validity.

Conclusions

Having sexual intercourse during pregnancy and resuming menstruation earlier were independent factors for resumption of sexual intercourse within 3 months after delivery. Almost all women who had postpartum sexual intercourse used various contraceptive methods.
Exposure to environmental chemicals and type 1 diabetes: an update
Authors: Howard Sarah G
Published: March 2019

This narrative review summarises recently published epidemiological and in vivo experimental studies on exposure to environmental chemicals and their potential role in the development of type 1 diabetes mellitus (T1DM). These studies focus on a variety of environmental chemical exposures, including to air pollution, arsenic, some persistent organic pollutants, pesticides, bisphenol A and phthalates. Of the 15 epidemiological studies identified, 14 include measurements of exposures during childhood, 2 include prenatal exposures and 1 includes adults over age 21. Together, they illustrate that the role of chemicals in T1DM may be complex and may depend on a variety of factors, such as exposure level, timing of exposure, nutritional status and chemical metabolism. While the evidence that these exposures may increase the risk of T1DM is still preliminary, it is critical to investigate this possibility further as a means of preventing T1DM.
Asymptomatic Profound Oxyhemoglobin Desaturation Following Interscalene Block in a Geriatric Patient
Authors: Smith Michael P. , Tetzlaff John E. , Brems John J.
Published: March 2019

Background and Objectives

Interscalene block can be chosen for complete anesthesia for shoulder surgery. Phrenic nerve block occurs with almost all interscalene blocks, but is well tolerated in most patients. This may not be the case in selected geriatric patients.

Methods

The patient is a 90-year-old female with osteoarthritis of the left shoulder scheduled for total shoulder anthroplasty. Past medical history revealed hypertension, mild mitral valve insufficiency, and a remote episode of congestive heart failure. She underwent interscalene block with 40 mL of 1.4% mepivacaine, 1:200,000 epinephrine freshly added, alkalinized with sodium bicarbonate.

Results

The onset of the block was rapid and complete. The patient had minimal intravenous sedation (0.5 mg midazolam) and was resting comfortably with a respiratory rate of 12-14 breaths/min. Approximately 5 minutes after the injection of local anesthetic, the patient was noted to be alert, cyanotic, denying dyspnea, with an oxygen saturation of 75-85%. A chest radiograph revealed elevation of the ipsilateral hemidiaphragm and no pneumothorax or other pathology. Despite supplemental oxygen by face mask, desaturation persisted and general anesthesia was induced. On emergence from anesthesia, the patient had a complete interscalene block. Repeat chest radiograph after resolution of the block revealed return of hemidiaphragm position and no other pathology. The patient was extubated in the recovery room without difficulty. Following extubation the patient demonstrated stable respirations and normal oxyhemoglobin saturation.

Conclusions

Ipsilateral phrenic nerve paralysis caused significant respiratory compromise in an elderly patient without known significant pulmonary disease.
Alginate gel entrapped ectomycorrhizal inoculum promoted growth of cuttings ofEucalyptusclones under nursery conditions
Authors: Costa Lidiomar Soares da , Grazziotti Paulo Henrique , Silva Alexandre Christófaro , Fonseca Arley José , Gomes Ângela Laís Fernandes , Grazziotti Danielle Cristina Fonseca Santos , Rossi Márcio José
Published: March 2019

Plant inoculation with ectomycorrhizal fungi (EMF) maximizes the productive potential of forest stands. Thus, the inoculation efficiency of calcium alginate gel entrapped EMF vegetative mycelium was evaluated in a commercial nursery using cuttings of Eucalyptus clones GG100 and GG680. The cuttings were inoculated with Pisolithus microcarpus G. Cunn. (Cooke & Massee), Hysterangium gardneri E. Fisch., and Scleroderma areolatum Ehrenb. The cuttings were cultivated under low phosphate fertilization and compared with uninoculated control treatments with reduced phosphate (low P control) and full phosphate (high P control) fertilization. Pisolithus microcarpus inoculation increased shoot height, root collar diameter, shoot dry mass, total dry mass, and frequency of maximum score for root ball formation of the two clones compared with the low P control treatment. Also, in relation to the low P control treatment, H. gardneri inoculation increased shoot dry mass in GG100 rooted cuttings. Scleroderma areolatum inoculation did not enhance any characteristic of Eucalyptus rooted cuttings. Inoculation of vegetative mycelium with EMF impregnated in calcium alginate gel intensified rooted cutting growth in a commercial Eucalyptus nursery and decreased the phosphate dose required. Based on the comparison of two Eucalyptus clones, efficiency of the inoculants in promoting benefits depends on the fungus and the Eucalyptus clone. Pisolithus microcarpus is most promising for inoculation in Eucalyptus cuttings.
Advances on Testing C-Planarity of Embedded Flat Clustered Graphs
Authors: Chimani Markus , Di Battista Giuseppe , Frati Fabrizio , Klein Karsten
Published: March 2019

In this paper, we show a polynomial-time algorithm for testing [Formula: see text]-planarity of embedded flat clustered graphs with at most two vertices per cluster on each face.

Our result is based on a reduction to the planar set of spanning trees in topological multigraphs (pssttm) problem, which is defined as follows. Given a (non-planar) topological multigraph [Formula: see text] with [Formula: see text] connected components [Formula: see text], do spanning trees of [Formula: see text] exist such that no two edges in any two spanning trees cross? Kratochvíl et al. [SIAM Journal on Discrete Mathematics, 4(2): 223–244, 1991] proved that the problem is NP-hard even if [Formula: see text]; on the other hand, Di Battista and Frati presented a linear-time algorithm to solve the pssttm problem for the case in which [Formula: see text] is a [Formula: see text]-planar topological multigraph [Journal of Graph Algorithms and Applications, 13(3): 349–378, 2009].

For any embedded flat clustered graph [Formula: see text], an instance [Formula: see text] of the pssttm problem can be constructed in polynomial time such that [Formula: see text] is [Formula: see text]-planar if and only if [Formula: see text] admits a solution. We show that, if [Formula: see text] has at most two vertices per cluster on each face, then it can be tested in polynomial time whether the corresponding instance [Formula: see text] of the pssttm problem is positive or negative. Our strategy for solving the pssttm problem on [Formula: see text] is to repeatedly perform a sequence of tests, which might let us conclude that [Formula: see text] is a negative instance, and simplifications, which might let us simplify [Formula: see text] by removing or contracting some edges. Most of these tests and simplifications are performed “locally”, by looking at the crossings involving a single edge or face of a connected component [Formula: see text] of [Formula: see text]; however, some tests and simplifications have to consider certain global structures in [Formula: see text], which we call [Formula: see text]-donuts. If no test concludes that [Formula: see text] is a negative instance of the pssttm problem, then the simplifications eventually transform [Formula: see text] into an equivalent [Formula: see text]-planar topological multigraph on which we can apply the cited linear-time algorithm by Di Battista and Frati.
On a Fire Fighter’s Problem
Authors: Klein Rolf , Langetepe Elmar , Schwarzwald Barbara , Levcopoulos Christos , Lingas Andrzej
Published: March 2019

Suppose that a circular fire spreads in the plane at unit speed. A single fire fighter can build a barrier at speed [Formula: see text]. How large must [Formula: see text] be to ensure that the fire can be contained, and how should the fire fighter proceed? We contribute two results.

First, we analyze the natural curve [Formula: see text] that develops when the fighter keeps building, at speed [Formula: see text], a barrier along the boundary of the expanding fire. We prove that the behavior of this spiralling curve is governed by a complex function [Formula: see text], where [Formula: see text] and [Formula: see text] are real functions of [Formula: see text]. For [Formula: see text] all zeroes are complex conjugate pairs. If [Formula: see text] denotes the complex argument of the conjugate pair nearest to the origin then, by residue calculus, the fire fighter needs [Formula: see text] rounds before the fire is contained. As [Formula: see text] decreases towards [Formula: see text] these two zeroes merge into a real one, so that argument [Formula: see text] goes to 0. Thus, curve [Formula: see text] does not contain the fire if the fighter moves at speed [Formula: see text]. (That speed [Formula: see text] is sufficient for containing the fire has been proposed before by Bressan et al. [6], who constructed a sequence of logarithmic spiral segments that stay strictly away from the fire.)

Second, we show that for any curve that visits the four coordinate half-axes in cyclic order, and in increasing distances from the origin the fire can not be contained if the speed [Formula: see text] is less than 1.618…, the golden ratio.
Triple-Cycle Permutations Over Finite Fields of Characteristic Two
Authors: Liu Xianping , Chen Yuan , Xu Yunge , Sun Zhimin
Published: March 2019

Triple-cycle permutations over finite fields of characteristic two are studied, and some classes of triple-cycle permutations are proposed in this paper. In addition, new triple-cycle permutations can be constructed by switching construction from known ones.
Extended phase-space thermodynamics of black holes in massive gravity
Authors: Pradhan Parthapratim
Published: March 2019

We study the extended phase-space thermodynamics of black holes in massive gravity. Particularly, we examine the critical behavior of this black hole using the extended phase-space formalism. Extended phase-space can be defined as one in which the cosmological constant should be treated as a thermodynamic pressure and its conjugate variable as a thermodynamic volume. In this phase-space, we derive the black hole equation of state, the critical pressure, the critical volume and the critical temperature at the critical point. We also derive the critical ratio of this black hole. Moreover, we derive the black hole reduced equation of state in terms of the reduced pressure, the reduced volume and the reduced temperature. Furthermore, we examine the Ehrenfest equations of black holes in massive gravity in the extended phase-space at the critical point. We show that the Ehrenfest equations are satisfied on this black hole and the black hole encounters a second-order phase transition at the critical point in the said phase-space. This is re-examined by evaluating the Pregogine–Defay ratio [Formula: see text]. We determine the value of this ratio is [Formula: see text]. The outcome of this study is completely analogous to the nature of liquid–gas phase transition at the critical point. This investigation also further gives us the profound understanding between the black hole of massive gravity with the liquid–gas system.
The Politics of Soft Power:Belt and Road Initiative (BRI) as Charm Influence in South Asia
Authors: Sharma Buddhi Prasad , Khatri Raunab Singh
Published: March 2019

Over the last three and half decades, China’s rapid advancement in development efforts has been accompanied by a conscious effort in projecting itself as a major frontrunner in the economy. Despite being a developing country (Huang, 2015), Chinese President Xi Jinping’s announcement in World Economic Forum (WEF) (Bruce-Lockhart, 2017) had hinted China’s growing interest in the development of trade and network among countries. The Belt and Road Initiative (BRI) is also one such development put forward to institutionalize China’s soft power presence in the world and create harmony with rest of the world. The Initiative has been placed as synonymous to a way of friendly cooperation signaling the project as “Road for Peace” (Kasturi, 2017). China has placed a tremendous amount of effort for its “charm offensive” approach with an estimated US$10 billion spending every year on its global soft power presence (Kurlantzick, 2017). Under the project, China has placed initiatives in approaching for regional connectivity in the South Asia region with China–Pakistan Economic Corridor (CPEC) being regarded as its flagship program. As it goes, of all the projects China has undertaken in the BRI, its ventures in South Asia are considered challenging and need strong cooperation (Stratfor Enterprises, 2017). The unstable geo-politics and security threats in the region pose Beijing with a lot to consider before it can preach about the peaceful connectivity. Most significant of all, the problems in the region will be with India as it has openly expressed its dissatisfaction towards BRI. India not only observes the initiative as a security threat with CPEC corridor passing through the controversial Kashmir area, but also sees it as an initiative to undermine its traditional influence in the region. As such, this paper tries to provide an analytical view of BRI with China’s soft power presence in the South Asia region.