bluuebunny/crossref_metadata_2025 huggingface dataset:
Clinical outcomes of trabecular microbypass stent (iStent®) implantation in medically controlled open‐angle glaucoma in the Korean population
Authors: Lim Suho
Published: January 2021

Purpose

To evaluate the safety and efficacy [intraocular pressure (IOP)‐lowering effect and medication use] of a single trabecular microbypass stent (iStent®; Glaukos Corp., San Clemente, CA, USA) for medically controlled open‐angle glaucoma.

Methods

This retrospective case‐series included 42 eyes of 34 patients with medically controlled open‐angle glaucoma with IOP less than 21 mmHg. Clinical outcomes analyzed were IOP, medication use, corrected distance visual acuity (CDVA), and surgical complications. Surgical success was defined according to three criteria: (A) IOP <21 mmHg without medication; (B) IOP <18 mmHg without medication; and (C) IOP <18 mmHg with or without medication. Patients were followed for a minimum of six months postoperatively.

Results

Mean IOP was reduced from 15.8 ± 2.8 mmHg to 14.5 ± 2.8 mmHg (p < 0.001), while mean number of medications decreased from 2.2 ± 1.2 to 0.8 ± 1.1 at final visit (p < 0.001). Surgical success rates were 78.6%, 61.9%, and 97.6% at six months and 78.6%, 59.5%, and 95.2% at final visits according to criteria A, B, and C. Meanwhile, 59.5% of patients were medication‐free at their final visit. The relative risk of surgical failure by Criterion B was 4.337 (95% confidence interval:1.799–10.454) times greater in the higher‐medication group (three or more preoperative medications). CDVA was significantly improved from 0.41 ± 0.10 to 0.09 ± 0.07 LogMAR in the combined phacoemulsification and iStent® implantation group (p < 0.001). There was no case whose vision was threatened (vision loss of two or more lines) or who showed severe complications after surgery.

Conclusions

Single trabecular microbypass stent implantation was effective in reducing IOP and medication usage in patients with open‐angle glaucoma with a low preoperative IOP. Our results imply that it is more difficult to achieve low target IOP control in eyes with higher numbers of preoperative medications.
Fight the silent thief of sight: glaucoma incidence in citizens of Sassari
Authors: Murgia Umberto , Brunoro Andrea
Published: January 2021

Purpose

To identify the silent thief of sight in asymptomatic citizens of Sassari and assess the importance of the screening in glaucoma.

Methods

Seven ophthalmologists performed free specialist examinations and included 322 asymptomatic subjects from 40 to 80 years. All volunteers attended the screening with assessment of intraocular pressure (IOP, air‐puff tonometer TX‐f Canon) and optic disc evaluation by fundus biomicroscopy. Subjects with optic nerve cupping underwent retinal nerve fiber layer (RNFL) and ganglion cell complex (GCC) thickness examination (i‐Vue OptoVue OCT).

Results

Subjects with a diagnosis of hypertension or treated for glaucoma were excluded. Of the total 322 volunteers included, 23.6% had glaucoma familiarity, 8.7% declared that the screening was the first ophthalmological visit and 55,28% stated that they had never been examined with tonometry before. IOP was >21 mmHg in the 7% and optic disc showed abnormal cupping in 6.8% of the volunteers. The 2.48% of the subjects had both ocular hypertension (IOP>21 mmHg) and papillary abnormalities, and 7.4% of the 27 OCT performed showed anomalies.

Conclusions

Glaucoma is one of the leading causes of irreversible blindness, but early detection and treatment could prevent severe vision loss. For these reasons, glaucoma screenings are fundamental even though they could have limited diagnostic power. In fact, subjects with OCT anomalies were directed to further examinations. The results of this screening are quite impressive, most of all the 8% of patients declaring that they had never underwent an ophthalmological visit and the 55% of patient that undertake a tonometry for the first time. The discrepancy between these data stresses the importance of a regular ophthalmological examination that is still confused with the visual acuity assessment made by opticians. Only a complete ophthalmological visit can diagnose conditions affecting irreversibly the vision, such as the silent thief of sight.
Geometric mapping of the eye lens and its epithelium reveals changes that accompany emmetropia
Authors: Quinlan Roy , Kalligeraki Alexia , Uwineza Alice , Jarrin Miguel
Published: January 2021

Purpose

To investigate changes in both lens shape and the epithelial distribution as emmetropia is established in C57Bl6J mice between postnatal weeks 4 to 6.

Methods

We used a computational approach to produce geometrical maps of the mouse lens and its epithelium. Conveniently our approach ulitises data collected from intact lenses imaged using a conventional laser scanning confocal microscope. It delivers cartesian coordinates for every epithelial cell in the lens epithelium. We chose to investigate lenses during postnatal weeks 4 to 6, a time during lens development when emmetropia is established in this inbred strain of mice (Tkatchenko et al., 2010).

Results

Geometric mapping standardises the measurement and analysis of lens epithelial cell densities. Emmetropia is established in C57Bl6J inbred mice, but many other strains exhibit considerable refractive error (Tkatchenko et al., 2019). The eye lens plays its part in the development and establishment of emmetropia in mice (Tkatchenko et al., 2010; Pardue et al., 2013). We record a change in the shape of the eye lens from a spheroid to a lentoid shape between postnatal weeks 4 and 6. The distribution of the epithelial cells in the lens epithelium also changes from a non‐zonal to a zonal distribution, with characteristics that typify the epithelia of adult animals. We correlate these observations regarding lens geometry with genetic mutations in lens cytoskeletal proteins found in those strains that present with refractive error, but which are absent from C57Bl6J (Sandilands et al., 2004). We discuss the potential significance of these observations in the context of the mechanistic basis of the lens contribution to emmetropia.

Conclusions

The development of emmetropia in the C57Bl6J inbred strain of mice correlates with changes in epithelial cell organisation and changes in lens geometry, which when combined with strain‐specific genetic differences offer a mechanistic understanding involving the lintermediate filament cytoskeleton.

Pardue, M. T., et al., (2013) Exp Eye Res, 114, 96–105.

Sandilands, A., et al (2004). Eye Res. 78, 109–123.

Tkatchenko, T. V. et al. (2019). BMC Medical Genomics, 12, 1–24.

Tkatchenko, T. V., Shen, Y. and Tkatchenko, A. V. (2010) Invest Ophth Vis Sci, 51, 21–27. https://doi.org/10.1167/iovs.08‐2767
Treatment of complex macular holes using a large disc of trypan blue stained‐lyophilized amniotic membrane: a 10 cases series with 1‐year follow‐up
Authors: Garcin Thibaud , Gain Philippe , Thuret Gilles
Published: January 2021

Purpose

Treatment of complex macular holes (MH) is challenging. The use of amniotic membrane (AM) has been described but is not yet codified, and we need to collect more cases.

Aim

To describe tips and tricks for the use of a large patch of lyophilized AM (lAM) in this indication.

Methods

Consecutive 10 cases series: two patients with severe MH‐induced rhegmatogenous retinal detachment (RRD), three with recurring RRD + persistant MH, five with persistant MH after inner limitant flap. Our IRB approved the study and all patients signed an informed consent. lAM (Visio Amtrix, TBF) was chosen because of its availability, easy handling, thinness and transparency. A 3‐ to 4‐mm diameter disc was trephined with a disposable punch, stained with 0.06% Trypan Blue (after a first failure due to poor visualization of an unstained lAM) and rinsed with BSS. Stained lAM were inserted through a 23G sclerotomy using a standard perfusion catheter and unfolded on top of the MH using a forceps and a backflush needle. Tamponade was done with gas (17% C2F6, Arceole; n = 6) or heavy silicone (Densiron 68, Fluoron; n = 4) depending of the case. Routine follow‐up was done for 12 months, including SD‐OCT (Spectralis, Heidelberg) and color fundus photography (CR2‐AF, Canon).

Results

Ten eyes of 10 patients of 62 ± 9 years with preoperative mean BCVA 1/80 (1.9 logMAR) and a mean minimal MH diameter of 942 ± 333 μm underwent surgery. The blue staining disappeared within 15 days. Anatomic success occurred for all patients: six/10 were closed, four/10 had reduced diameter. BCVA improved in all cases. The five RRD were reattached without recurrence. Apart one failure (lAM left unfolded) with migration at day 1 and MH closed with central scar, no secondary displacement of the patch occurred.

Conclusions

A large patch of lAM seems a new method to cure complex MH in different situations. Trypan blue staining is, in our hand, absolutely necessary to allow correct positioning. Complete unfolding seems also required to allow good adherence over the MH.
Temperature monitoring in vitreoretinal surgery
Authors: Anatychuk Lukyan , Pasyechnikova Nataliya , Naumenko Volodimir , Kobylianskyi Roman , Nazaretyan Rudolf , Zadorozhnyy Oleg
Published: January 2021

Purpose

To study the dynamics of epibulbar and intraocular temperature during vitreoretinal surgery.

Methods

This pilot study included 20 patients with rhegmatogenous retinal detachment (10 eyes) and proliferative diabetic retinopathy (10 eyes). All patients underwent vitreoretinal surgery with room temperature irrigation solution. In all cases, the ambient temperature, the patient's body temperature, the temperature of the irrigating solution, temperature in the anterior, mid‐ and posterior vitreous were recorded during surgery. Pre and post‐operative thermometry was also performed on the outer ocular surface.

Results

During vitreoretinal surgery with room temperature (24.2 ± 0.52°C) irrigation solution, a decrease in temperature (p < 0.001) versus the initial one was found in all segments of the vitreous cavity. In the absence of continuous irrigation, a rapid rewarming of the vitreous cavity was noted (an average of 0.18°C per minute). Our study also demonstrated the presence of regional hyperthermia of the operated eye in a number of patients (25%) in the post‐operative period.

Conclusions

Current research shows that vitreoretinal surgery is performed under conditions of uncontrolled local ocular hypothermia is characterized by a rapid uncontrolled rewarming of the vitreous cavity after cessation of cooling, and in the post‐operative period, local hyperthermia of the operated eye is observed in a number of patients.
Leber's Hereditary Optic Neuropathy‐like syndrome in heteroplasmic mitochondrial mutations
Authors: Chan Jane , Sadun Alfredo
Published: January 2021

Purpose

Leber's Plus syndromes have been well described in the literature. Intriguingly, an opposite effect occurs when heteroplasmy with more severe mitochondrial mutations present with an Leber's Hereditary Optic Neuropathy (LHON)‐like visual loss at a later age of onset. The small, unmyelinated papillomacular bundle (PMB) fibers are selectively affected first in these heteroplasmic mitochondrial mutations.

Methods

Case report.

Results

Twenty‐year‐old woman with subacute bilateral sequential visual loss (CF @2 feet OD; 20/400+1 OS, no RAPD; central scotoma OU; temporal disc pallor OU; superior, temporal, and inferior RNFL thinning OU; diffuse GCL/IPL thinning OU) presented with an LHON‐like syndrome with a non‐LHON mutation, a pathogenic variant in MT‐ND3 m.10197G>A (p. Ala47Thr) with 51% heteroplasmy. Idebenone and vitamin C resulted in mild visual improvement.

Conclusions

We hypothesize that an LHON‐like presentation can be a form fruste of more severe heteroplasmic pathogenic mitochondrial mutations at a later age of onset, irrespective of the mitochondrial DNA (mtDNA) mutation type. Other factors can play a role in the clinical phenotype, including DNA haplotype, nuclear genetic background, environmental factors, etc. Although the mtDNA 10197G>A mutation has been associated with Leigh syndrome (LS), LHON/dystonia (LDYT), and MELAS/LS overlap syndrome,1 our 20‐year‐old woman had only LHON‐like visual loss at the onset of presentation. In all cases, the PMB is most vulnerable to oxidative damage.2 Although these mtDNA mutations affect different ND subunits of complex I, some electrons seem to be transferred through a parallel pathway to complex II, as shown in cybrid studies.3

References

1. Leng Y, et al. The mitochondrial DNA 1019 G > A mutation causes MELAS/Leigh overlap syndrome presenting with acute auditory agnosia. Mitochondrial DNA. 2015; 208‐212.

2. Pan BX, et al. Mathematically modeling involvement of axons in Leber's hereditary optic neuropathy. Invest Ophthalmol Vis Sci. 2012; 53: 7608–7617.

3. Caporali L, et al. Cybrid studies establish the causal link between the mtDNA m.3890G>A/MT‐ND1 mutation and optic atrophy with bilateral brainstem lesions. Biochim Biophys Acta. 2013; 1832: 445–452.
Second primary neoplasms in patients with primary orbital lymphoma: a population‐based study 1992 to 2016
Authors: Tadrosse Abanoob , Mikhael Sandra , Tadrosse Marina , Tadrosse Mark , Langer Paul D.
Published: January 2021

Purpose

To investigate, in a population‐based study, the risk of developing second primary neoplasms (SPNs) after a diagnosis of primary orbital lymphoma (OL).

Methods

Data on a cohort of patients with a diagnosis of primary OL as their first malignancy were extracted from the Surveillance, Epidemiology, and End Results US registry from 1992 to 2016. Observed‐to‐expected ratio of developing SPNs was calculated to estimate relative risk (RR) and associated 95% confidence interval (CI), which were compared to a reference population (RP) matched for age, sex, race, and calendar year.

Results

A total of 1063 patients with primary OL were identified, 14% of whom developed SPNs. Mean age at OL diagnosis was 66 years old, while that at a SPN diagnosis was 74. There was a significant 20% excess risk of SPNs development in OL patients compared to the RP (p < 0.05). Two to 11 months after OL diagnosis, there was an increased risk of respiratory tract malignancies [RR: 3.2 (95% CI: 1.2–6.9); p < 0.05], while 10–15 years after diagnosis, there was an increased risk of colorectal cancer [RR: 3.0 (95% CI: 1.1–6.4); p < 0.05]. Stratification by sex revealed an increased risk of prostate cancer development in males [RR: 3.4 (95% CI: 1.1–8.0); p < 0.05]. Patients aged 40–59 years old experienced the greatest burden of SPNs with a significant 46% excess risk compared to the RP (p < 0.05). Radiotherapy‐treated patients were at a higher risk of thyroid SPNs [RR: 3.8 (95% CI: 1.04–9.6); p < 0.05].

Conclusions

Patients with primary OL experience a 20% increased risk of SPNs compared to the RP. Two to 11 months and 10–15 years after OL diagnosis mark an increased risk of respiratory tract and colorectal SPNs, respectively. Male OL patients tend to more readily develop prostate malignancies than the RP. Patients 40–59 years old display the highest risk of SPNs. Radiotherapy is associated with an increased risk of developing thyroid neoplasms. Patients who are diagnosed with primary orbital lymphoma should be followed with these risks in mind.

Bibliography

Surveillance Research Program, National Cancer Institute SEER*Stat software (www.seer.cancer.gov/seerstat) version 8.3.6.1.
OCTA parameters of the peripapillary retina and optic disk in older age group
Authors: Ioyleva Elena , Safonenko Alexandra
Published: January 2021

Purpose

To investigate the OCTA parameters of the peripapillary retina and optic disk in Caucasian people of an older age group

Methods

Thirty‐four patients (68 eyes), 14 male and 20 female, mean age 57.1 ± 9.6 were examine. All patients underwent OCT and OCTA examination (RTVue‐XR, Optovue), by using protocol ‘HD Angio Disk’ 4.5*4.5 mm. OCT and OCTA were used to measure the radial peripapillary capillaries (RPC, %) and retinal nerve fiber layer thickness (RNFL, µm), rim area, disc area, cup volume.

Results

Mean value of the RNFL thickness was 109.7 ± 11.1 µm. The lower value of the RNFL thickness was observed in ‘Tempo Inferior’ and ‘Tempo Superior’ segments. Rim area was 1.66 ± 0.33 mm2, disc area—1.87 ± 0.28 mm2. The mean value of RPC density in peripapillary retina was 52.2 ± 2.3%. The lower value of the RPC density was in ‘Nasal Inferior’ and ‘Superior Nasal’ segments, 48.9 ± 3.2% and 49.9 ± 3.1%, respectively.
Hot air convective drying of small cardamom (Elettaria cardamomum Maton): Evaluation of drying, color, and aroma kinetics
Authors: Mishra Sushreesmita , Sahu Jatindra K. , Sanwal Nikita , Sharma Nitya
Published: January 2021

Effect of temperatures (40, 50, and 60°C) on quality attributes of small cardamom (Elettaria cardamomum Maton) during hot air convective (HAC) drying was investigated. Kinetics of moisture, color and aroma during the HAC drying were analyzed. Among seven 2‐ and 3‐term exponential models, the Logistic model was best‐fitted to the drying data. Moisture transfer rates were found out to be 1.62 × 10−8, 2.51 × 10−8, and 3.64 × 10−8 m2 s−1 at 40, 50, and 60°C, respectively, and the activation energy of diffusion was 34.96 kJ mol−1. When surface color (L*, a*, and b*) and aroma (essential oil yield) were considered as another two quality criteria during the drying of cardamom capsules, samples dried at 50°C was observed to be the best. With drying time, the value of L* decreased, a* value increased, and b* value of cardamom samples increased. Weibull model yielded the higher correlation coefficient between the predicted and the experimental data of color parameters (L* and a*) whereas the Zero‐order model was fitted well for b* values for the entire temperature range. Aroma calculated as essential oil yield (% dry basis) increased with drying time due to the release of a large number of volatile components during the drying.

Practical Application

Small cardamom so far is known to have best among the spices in terms of quality. Although India is among the largest consumer and producer of cardamom, cardamom growers adopt the age‐old processing practices. Furthermore, there is the absence of systematic study and scientific understanding in the existing practice of cardamom drying. The existing design and development of a dryer suitable for cardamom capsules are highly dependent on moisture, color, and aroma profile during drying. Studying drying kinetics along with postprocessing quality evaluation such as color and aroma would support as preliminary information for the development of suitable dryers for optimum retention of color and aroma of cardamom capsules during the drying.
Visual and Cognitive Impairments Differentially Affect Speed Limit Compliance in Older Drivers
Authors: Wang Shefang , Sharma Anuj , Dawson Jeffrey , Rizzo Matthew , Merickel Jennifer
Published: January 2021

Objectives

We test the hypothesis that clinical measures of age‐related cognitive, visual, and mobility impairments negatively impact older driver speed limit compliance to advance method developments that improve older patient care and screen, identify, and advise at‐risk older drivers.

Design

Real‐world driver behaviors of older adults who had a range of cognitive, visual, and mobility abilities (measured with standardized, clinical tests) were assessed in environmental context (e.g., speed limit, traffic density, roadway type). Older driver speed limit compliance was measured in constant speed limit zones and at transition zones, where speed limits changed.

Setting

A naturalistic driving study of older adults living around Omaha, Nebraska.

Participants

Seventy‐seven, legally licensed, active, and typically aging older drivers (65–90 years) who had a range of cognitive and visual abilities.

Measurements

Drivers typical, daily driving was continuously monitored for 3 months using sensor instrumentation installed in their own vehicles. At study start, each participant completed a comprehensive, standardized, clinical assessment of cognitive, visual, and mobility abilities relevant to aging and driving.

Results

Older drivers with greater cognitive impairment (P = .10) drove slower than drivers with less cognitive impairment, linking cognitive impairment to speed control. Drivers with greater visual impairment overall complied less with speed limit changes at transition zones (P = .01) and were more likely to comply with speed limit transitions when they occurred concurrently with changes in roadway features (P < .01).

Conclusion

Results link clinical measures of age‐related cognitive and visual impairment to impaired driver safety in real‐world contexts. Real‐world sensor data coupled with detailed, personalized older driver profiles can inform patients, caregivers, interventions, policy, and the design of supportive in‐vehicle technology for at‐risk older drivers.
Fsp1 cardiac embryonic expression delineates atrioventricular endocardial cushion, coronary venous and lymphatic valve development
Authors: Cano‐Ballesteros Sara , Palmquist‐Gomes Paul , Marín‐Sedeño Ernesto , Guadix Juan Antonio , Pérez‐Pomares José María
Published: January 2021

Fsp1 (a.k.a S100A4 or Metastatin) is an intracellular and secreted protein widely regarded as a fibroblast marker. Recent studies have nonetheless shown that Fsp1 is also expressed by other cell types, including small subsets of endothelial cells. Since no detailed and systematic description of Fsp1 spatio‐temporal expression pattern in cardiac vascular cells is available in the literature, we have used a transgenic murine line (Fsp1‐GFP) to study Fsp1 expression in the developing and postnatal cardiac vasculature and endocardium. Our work shows that Fsp1 is expressed in the endocardium and mesenchyme of atrioventricular valve primordia, as well as in some coronary venous and lymphatic endothelial cells. Fsp1 expression in cardiac venous and lymphatic endothelium is progressively restricted to the leaflets of cardiac venous and lymphatic valves. Our results suggest that Fsp1 could play a role in the development of atrioventricular valves and participate in the patterning and morphogenesis of cardiac venous and lymphatic vessel valves.
Fe‐redox changes in Itokawa space‐weathered rims
Authors: Hicks L. J. , Bridges J. C. , Noguchi T. , Miyake A. , Piercy J. D. , Baker S. H.
Published: January 2021

Synchrotron Fe‐K X‐ray absorption spectroscopy and transmission electron microscopy have been used to investigate the mineralogy and Fe‐redox variations in the space‐weathered (SW) rims of asteroidal samples. This study focuses on the FIB lift‐out sections from five Itokawa grains, returned by the Hayabusa spacecraft, including samples RB‐QD04‐0063, RB‐QD04‐0080, RB‐CV‐0011, RB‐CV‐0089, and RB‐CV‐0148. Each of the samples featured partially amorphized SW rims, caused by irradiation damage from implanted low mass solar wind ions, and the impacting of micrometeorites. Using bright‐field and HAADF‐STEM imaging, vesicular blistering and nanophase Fe metal (npFe0) particles were observed within grain rims, and solar flare tracks were observed in the substrate host grain, confirming the presence of SW zones. We use Fe‐K XANES mapping to investigate Fe‐redox changes between the host mineral and the SW zones. All SW zones measured show some increases in the ferric‐ferrous ratio (Fe3+/ΣFe) relative to their respective host grains, likely the result of the implanted solar wind H+ ions reacting with the segregated ferrous Fe in the surface material.
Artabotrys chitkokoi (Annonaceae), a new species discovered in Sagaing Region, Myanmar
Authors: Hein Khant Zaw , Naive Mark Arcebal K. , Chen Junhao
Published: January 2021

Artabotrys chitkokoi K.Z.Hein, Naive & J.Chen from Sagaing Region, Myanmar, is described and illustrated as a species new to science. Description, colour plates, discussion of similar taxa, phenology, distribution and a preliminary conservation status assessment are provided. With this discovery, Myanmar now holds a total of eight Artabotrys species and a key to these species is provided.
Does Data Drive Policymaking? A Multiple Streams Perspective on the Relationship Between Indicators and Agenda Setting
Authors: DeLeo Rob A. , Duarte Alex
Published: January 2021

The multiple streams framework (MSF) hypothesizes changes in problem indicators or data documenting the scale and scope a problem help draw policymaker attention to previously ignored issues. We test this hypothesis by systematically analyzing agenda setting and agenda denial in the United States Congress in response to indicators of the opioid crisis, namely opioid overdose deaths. We confirm that changes in indicators can, in some cases, help facilitate agenda setting and policy change. However, we also show indicator politicization, which refers to the extent to which changes in a particular indicator threaten the economic and political interests of groups operating in the political stream, is inversely related to issue attention. We, therefore, suggest refining existing MSF hypotheses to allow for a more nuanced understanding of the relationship between indicators and agenda setting.
Performance Improvement of a Two-Stage Proportional Valve With Internal Hydraulic Position Feedback
Authors: Wang He , Wang Xiaohu , Huang Jiahai , Quan Long
Published: January 2021

The present research concentrates on the performance improvement of a two-stage proportional valve with internal hydraulic position feedback which is named as the Valvistor valve. In this paper, the performance constraint of this valve is identified and a novel electronic closed-loop control strategy with an integral-separation fuzzy proportional-integral-derivative controller is proposed to improve the valve performance, including the static characteristics and the dynamic characteristics. The results show that in the Valvistor valve, the comparison point and the feedback loop for the internal hydraulic position feedback is only in the main stage, while the input is in the pilot stage. This leads to the poor performance of this valve. The control strategy is very effective and the performance of the Valvistor valve is improved. With the control strategy, the error of the poppet displacement is reduced from 4.9% to 2.1% by adjusting the spool displacement in the pilot stage in real-time and the flow error is reduced from 5.3% to 2.3%. The dead zone of the poppet displacement and the flow is eliminated. The hysteresis is reduced from 5.3% to 2.6% and the linearity is improved. The overshoot is reduced from 0.06 to 0.02 mm and the settling time is reduced from 0.5 to 0.2 s. Moreover, the bandwidth is increased from 8 to 16 Hz.
Advanced Dynamics Analysis of a Drilling Stabilizer
Authors: Adewuya Opeyemi
Published: January 2021

Discrete models of two drilling stabilizer designs are subject to analytical mechanics treatments to examine dynamic behavior and amplify insights into contribution to bottom-hole drilling assembly (BHA) dynamics stability. The spiral blade and straight blade design stabilizers are essential components of oil and gas BHA included to functionally provide stabilization during rotation of the BHA and stand-off from the walls of the oil and gas wellbore. Attempts are made from the onset to simplify model complexity and as a consequence ease of computational simulation. The answer to the seemingly intuitive question of the mechanical advantage offered by a spiral blade compared to a straight blade stabilizer design in a constrained dynamics representation is revealed by computing forces generated at the interface between the functional elements of the devices and the inelastic boundary (wellbore) to keep the constraint satisfied. Analytical mechanics approaches have been used to carry out 3-D dynamics analysis of bottom hole drilling assemblies using 3-D Euler-Bernoulli or Timoshenko beam-column finite-element representations and lumped-parameter model approximations of rigid body dynamics behavior. In this work, phase portraits of angular velocity versus displacement — parsed for torque generated — from numerical simulations for torque-free and applied external load states, and discussion, offer illuminating insights into downhole operating dynamics of these ubiquitous components of oil and gas well bottom hole assembly (BHA) drilling devices.
Decentralized Iterative Learning Cooperative Impedance Control for a Team of Robot Manipulators
Authors: Jin Xu
Published: January 2021

In this work, we propose a novel decentralized iterative learning cooperative impedance control (ILCIC) framework to cooperatively control the impedance of a robot manipulator team that operates in an iterative manner. Using a novel notion of neighbourhood impedance error, a formation-based architecture based on an undirected communication graph is proposed so that all robots in the team can achieve the desired impedance, even though some robot manipulators may not know the desired angle profiles and their relative configuration with respect to these desired angles. Furthermore, these desired angle profiles and the desired impedance model can be iteration dependent, as the robot manipulator team may need to accomplish different task objectives. Alignment initial conditions are considered, relaxing the identical initial condition (i.i.c.) often considered in the iterative learning control literature which can be restrictive in robotic applications. Through rigourous analysis, it is shown that the impedance error for each robot manipulator converges to zero over the iteration domain, in the sense of LT2-norm. In the end a simulation example on two 2DOF robot manipulators following a leader robotis presented to demonstrate the efficacy of the proposed framework.
Modeling and Parameter Identification for Condition Monitoring of Surface-Mount Permanent Magnet Machines Under Magnet Demagnetization
Authors: Pinto Delgado Fanny , Song Ziyou , Hofmann Heath F. , Sun Jing
Published: January 2021

Permanent Magnet Synchronous Machines (PMSMs) have been preferred for high-performance applications due to their high torque density, high power density, high control accuracy, and high efficiency over a wide operating range. During operation, monitoring the PMSM’s health condition is crucial for detecting any anomalies so that performance degradation, maintenance/downtime costs, and safety hazards can be avoided. In particular, demagnetization of PMSMs can lead to not only degraded performance but also high maintenance cost as they are the most expensive components in a PMSM. In this paper, an equivalent two-phase model for surface-mount permanent magnet (SMPM) machines under permanent magnet demagnetization is formulated and a parameter estimator is proposed for condition monitoring purposes. The performance of the proposed estimator is investigated through analysis and simulation under different conditions, and compared with a parameter estimator based on the standard SMPM machine model. In terms of information that can be extracted for fault diagnosis and condition monitoring, the proposed estimator exhibits advantages over the standard-model-based estimator as it can differentiate between uniform demagnetization over all poles and asymmetric demagnetization between north and south poles.
Physics Based Multi-Fidelity Data Fusion for Efficient Characterization of Mode Shape Variation Under Uncertainties
Authors: Zhou K. , Tang J.
Published: January 2021

Efficient prediction of mode shape variation under uncertainties is important for design and control. While Monte Carlo simulation (MCS) is straightforward, it is computationally expensive and not feasible for complex structures with high dimensionalities. To address this issue, in this study we develop a multi-fidelity data fusion approach with an enhanced Gaussian process (GP) architecture to evaluate mode shape variation. Since the process to acquire high-fidelity data from full-scale physical model usually is costly, we involve an order-reduced model to rapidly generate a relatively large amount of low-fidelity data. Combining these with a small amount of high-fidelity data altogether, we can establish a Gaussian process meta-model and use it for efficient model shape prediction. This enhanced meta-model allows one to capture the intrinsic correlation of model shape amplitudes at different locations by incorporating a multi-response strategy. Comprehensive case studies are performed for methodology validation.
The Effect of Time Delay on the Stability Control of Trailers
Authors: Horvath Hanna Zs. , Takacs Denes
Published: January 2021

The instability of the car-trailer systems very often leads to the snaking and/or rocking motions of trailers. In order to reduce the safety risk of these unwanted vibrations, stability control can be applied. In this paper, we use a spatial trailer model to analyze the effect of a possible control algorithm, which actuates by means of braking. For the sake of simplicity, the dynamics of the towing vehicle is modeled by the lateral displacement of the tow hitch that is supported laterally by a spring and damper. The longitudinal speed of the vehicle is kept constant. The effect of the braking forces are emulated in our study via a control torque, which is proportional to the yaw angle and the yaw rate. The time delay of the controller is also considered. Linear stability charts are constructed in the plane of the different system parameters. Linearly stable and unstable parameter domains are identified both for the vertical position of the center of gravity and the control gains. Numerical simulations are used to validate the theoretical results.
A Novel Plate-Like Sensor Utilizing Curvature-Based Stiffening for Nanometrology Applications
Authors: Shihab Rafiul , Jalil Tasmirul , Gulsacan Burak , Aureli Matteo , Tung Ryan C.
Published: January 2021

In this study, we propose a novel plate-like sensor which utilizes curvature-based stiffening effects for enhanced nanometrology. In the proposed concept, the stiffness and natural frequencies of the sensor can be arbitrarily adjusted by applying a transverse curvature via piezoelectric actuators, thereby enabling resonance amplification over a broad range of frequencies. The concept is validated using a macroscale experiment. Then, a microscale finite element analysis is used to study the effect of applied curvature on the microplate static stiffness and natural frequencies. We show that imposed transverse curvature is an effective way to tune the in-situ static stiffness and natural frequencies of the plate sensor system. These findings will form the basis of future curvature-based stiffening microscale studies for novel scenarios in atomic force microscopy.
Adjacent Terrestrial Landscapes Impact the Biogeographical Pattern of Soil Escherichia coli Strains in Produce Fields by Modifying the Importance of Environmental Selection and Dispersal
Authors: Liao Jingqiu , Bergholz Peter , Wiedmann Martin
Published: January 2021

Understanding the ecology of enteric bacteria in extrahost environments is important for the development and implementation of strategies to minimize preharvest contamination of produce with enteric pathogens. Our findings suggest that watershed landscape is an important factor influencing the importance of ecological drivers and dispersal patterns of
E. coli
.
TK1211 Encodes an Amino Acid Racemase towards Leucine and Methionine in the Hyperthermophilic Archaeon Thermococcus kodakarensis
Authors: Zheng Ren-Chao , Lu Xia-Feng , Tomita Hiroya , Hachisuka Shin-ichi , Zheng Yu-Guo , Atomi Haruyuki
Published: January 2021

Phylogenetic analysis of aminotransferase class III proteins from all domains of life reveals numerous groups of protein sequences. One of these groups includes a large number of sequences from
Thermococcales
species and can be divided into four subgroups.
SARS-CoV-2 Genomic Variation in Space and Time in Hospitalized Patients in Philadelphia
Authors: Everett John , Hokama Pascha , Roche Aoife M. , Reddy Shantan , Hwang Young , Kessler Lyanna , Glascock Abigail , Li Yize , Whelan Jillian N. , Weiss Susan R. , Sherrill-Mix Scott , McCormick Kevin , Whiteside Samantha A. , Graham-Wooten Jevon , Khatib Layla A. , Fitzgerald Ayannah S. , Collman Ronald G. , Bushman Frederic
Published: January 2021

Understanding how SARS-CoV-2 spreads globally and within infected individuals is critical to the development of mitigation strategies. We found that most lineages in Philadelphia had resembled sequences from New York, suggesting infection primarily but not exclusively from this location.
Concurrent terbinafine-induced acute generalised exanthematous pustulosis and hepatitis
Authors: Carnio Lorenzo R , Johnson Shaw Mary E , Schnur Jack , Casadesus Damian
Published: January 2021

Terbinafine is a commonly used antifungal medication. Its side effects, while widely known, are rarely described and can be missed by the medical community. We present a 55-year-old woman who visited her primary care physician with onychomycosis. She started treatment with terbinafine, and 1 week later developed a rash in the left flank that extended to the chest, back, and upper part of lower extremities. Laboratory results showed elevated liver enzymes. A treatment with steroids did not improve the rash and she was admitted to our institution. She was started with intravenous dexamethasone, topical hydrocortisone and triamcinolone. Seven days later the liver enzymes normalised, and the rash resolved on the chest and back. Our patient had concurrent acute generalised exanthematous pustulosis and hepatitis that together has been very rarely associated with terbinafine.
Hereditary pseudocholinesterase deficiency discovery after electroconvulsive therapy
Authors: Pradhan Basant K , van Helmond Noud , Mitrev Ludmil V , Andonakakis Angelo A
Published: January 2021

Inherited pseudocholinesterase deficiency refers to an uncommon defect in the butyrylcholinesterase enzyme which can result in prolonged muscle paralysis due to delayed breakdown of choline ester paralytic anaesthetic agents. We describe a 25-year-old woman receiving electroconvulsive therapy (ECT) for treatment of depression in whom motor function did not recover adequately after administration of succinylcholine. Investigated post-ECT, she was found to have severe pseudocholinesterase deficiency. Implications of pseudocholinesterase deficiency for ECT treatment and anaesthetic strategies are discussed.
Defining a research agenda for youth sport specialisation in the USA: the AMSSM Youth Early Sport Specialization Summit
Authors: Kliethermes Stephanie A , Marshall Stephen W , LaBella Cynthia R , Watson Andrew M , Brenner Joel S , Nagle Kyle B , Jayanthi Neeru , Brooks M Alison , Tenforde Adam S , Herman Daniel C , DiFiori John P , Beutler Anthony I
Published: January 2021

Sport specialisation is becoming increasingly common among youth and adolescent athletes in the USA and many have raised concern about this trend. Although research on sport specialisation has grown significantly, numerous pressing questions remain pertaining to short-term and long-term effects of specialisation on the health and well-being of youth, including the increased risk of overuse injury and burnout. Many current elite athletes did not specialise at an early age. Methodological and study design limitations impact the quality of current literature, and researchers need to prioritise pressing research questions to promote safe and healthy youth sport participation. The American Medical Society for Sports Medicine hosted a Youth Early Sport Specialization Summit in April 2019 with the goal of synthesising and reviewing current scientific knowledge and developing a research agenda to guide future research in the field based on the identified gaps in knowledge. This statement provides a broad summary of the existing literature, gaps and limitations in current evidence and identifies key research priorities to help guide researchers conducting research on youth sport specialisation. Our goals are to help improve the quality and relevance of research on youth sport specialisation and to ultimately assure that opportunities for healthy and safe sport participation continue for all youth.
Hormonal contraceptive prescriptions in the UK Armed Forces
Authors: Double Rebecca L , Wardle S L , O'Leary T J , Weaden N , Bailey G , Greeves J P
Published: January 2021

Introduction

Thirty four per cent of women use hormonal contraceptives in the UK and the contraceptive pill is the most common method. There are no comparable data in the UK Armed Forces, but servicewomen are often required to complete physically arduous job roles in combat zones and may be more likely to take contraceptives to control or stop menstrual bleeding than the general population. We explored the prevalence of hormonal contraceptive prescriptions in the UK Armed Forces.

Methods

The study used defence medical records (Defence Medical Information Capability Programme) to identify hormonal contraceptive prescriptions for all serving regular UK servicewomen (n=15 738) as of 1 September 2017.

Results

Thirty one per cent of servicewomen (Royal Navy, 28%; British Army, 30%; Royal Air Force, 34%) had a current prescription for a hormonal contraceptive. Non-officer ranks were more likely to have a prescription for a hormonal contraceptive (32%) than officers (27%) (p<0.01). The contraceptive pill was more commonly prescribed (68%) than long-acting reversible contraceptive methods (32%) (contraceptive injection, 11%; contraceptive implant, 11%; intrauterine device, 10%).

Conclusion

Prescription data suggest that the prevalence of hormonal contraceptive use in UK servicewomen is comparable with the general UK population. These findings suggest that military service does not influence prevalence or choice of hormonal contraceptives.
Systems approach to health service design, delivery and improvement: a systematic review and meta-analysis
Authors: Komashie Alexander , Ward James , Bashford Tom , Dickerson Terry , Kaya Gulsum Kubra , Liu Yuanyuan , Kuhn Isla , Günay Aslι , Kohler Katharina , Boddy Nicholas , O'Kelly Eugenia , Masters Joseph , Dean John , Meads Catherine , Clarkson P John
Published: January 2021

Objectives

To systematically review the evidence base for a systems approach to healthcare design, delivery or improvement.

Design

Systematic review with meta-analyses.

Methods

Included were studies in any patients, in any healthcare setting where a systems approach was compared with usual care which reported quantitative results for any outcomes for both groups. We searched Medline, Embase, HMIC, Health Business Elite, Web of Science, Scopus, PsycINFO and CINAHL from inception to 28 May 2019 for relevant studies. These were screened, and data extracted independently and in duplicate. Study outcomes were stratified by study design and whether they reported patient and/or service outcomes. Meta-analysis was conducted with Revman software V.5.3 using ORs—heterogeneity was assessed using I2statistics.

Results

Of 11 405 records 35 studies were included, of which 28 (80%) were before-and-after design only, five were both before-and-after and concurrent design, and two were randomised controlled trials (RCTs). There was heterogeneity of interventions and wide variation in reported outcome types. Almost all results showed health improvement where systems approaches were used. Study quality varied widely. Exploratory meta-analysis of these suggested favourable effects on both patient outcomes (n=14, OR=0.52 (95% CI 0.38 to 0.71) I2=91%), and service outcomes (n=18, OR=0.40 (95% CI 0.31 to 0.52) I2=97%).

Conclusions

This study suggests that a systems approaches to healthcare design and delivery results in a statistically significant improvement to both patient and service outcomes. However, better quality studies, particularly RCTs are needed.

PROSPERO registration number

CRD42017065920.
Causal modelling of variation in clinical practice and long-term outcomes of ADHD using Norwegian registry data: the ADHD controversy project
Authors: Mykletun Arnstein , Widding-Havneraas Tarjei , Chaulagain Ashmita , Lyhmann Ingvild , Bjelland Ingvar , Halmøy Anne , Elwert Felix , Butterworth Peter , Markussen Simen , Zachrisson Henrik Daae , Rypdal Knut
Published: January 2021

Introduction

Attention-deficit/hyperactivity disorder (ADHD) is among the most common mental disorders in children and adolescents, and it is a strong risk factor for several adverse psychosocial outcomes over the lifespan. There are large between-country and within-country variations in diagnosis and medication rates. Due to ethical and practical considerations, a few studies have examined the effects of receiving a diagnosis, and there is a lack of research on effects of medication on long-term outcomes.

Our project has four aims organised in four work packages: (WP1) To examine the prognosis of ADHD (with and without medication) compared with patients with other psychiatric diagnoses, patients in contact with public sector child and adolescent psychiatric outpatient clinics (without diagnosis) and the general population; (WP2) Examine within-country variation in ADHD diagnoses and medication rates by clinics’ catchment area; and(WP3) Identify causal effects of being diagnosed with ADHD and (WP4) ADHD medication on long-term outcomes.

Method and analysis

Our project links several nationwide Norwegian registries. The patient sample is all persons aged 5–18 years that were in contact with public sector child and adolescent psychiatric outpatient clinics in 2009–2011. Our comparative analysis of prognosis will be based on survival analysis and mixed-effects models. Our analysis of variation will apply mixed-effects models and generalised linear models. We have two identification strategies for the effect of being diagnosed with ADHD and of receiving medication on long-term outcomes. Both strategies rely on using preference-based instrumental variables, which in our project are based on provider preferences for ADHD diagnosis and medication.

Ethics and dissemination

The project is approved by the Regional Ethics Committee, Norway (REC number 2017/2150/REC south-east D). All papers will be published in open-access journals and results will be presented in national and international conferences.

Trial registration numbers

ISRCTN11573246andISRCTN11891971.