bluuebunny/crossref_metadata_2025 huggingface dataset:
Heat Transfer Behavior During Water Spray Quenching of 7xxx Aluminum Alloy Plates
Authors: Fan Ning , Xiong Baiqing , Li Zhihui , Li Yanan , Li Xiwu , Zhang Yongan , Wen Kai , Yan Hongwei
Published: July 2021

The desired microstructure and mechanical properties of heat treatable 7xxx aluminum alloy can be achieved after spray quenching by controlling spray parameters. However, heat transfer behavior between specimen and quenchant is transient and complicated in quenching process. In this paper, a spray quenching system was utilized to quench for 7xxx aluminum alloy. The influence of spray parameters, including spray pressure and spray distance, on heat transfer behavior was examined and discussed. Heat flux (HF) and heat transfer coefficient (HTC) were calculated by iterative method. The results indicated that the aluminum alloy experienced transition boiling, nucleate boiling, and convection cooling regimes during spray quenching process. Heat transfer capability first increased and then decreased with the increasing of spray pressure or spray distance. A function of local heat transfer coefficient (L-HTC) which is variable in specimen surface temperature, spray parameters, and spatial location was constructed. Residual stress of 7xxx aluminum alloy plates was increased first and then slightly differed with the increase of volumetric flux.
Mechanical Analysis of a Thermo-Hydroforming Fiber-Reinforced Composite Using a Preferred Fiber Orientation Model and Considering Viscoelastic Properties
Authors: Ahn Hyunchul , Park Taejoon , Li Yumeng , Yeo Sang Young , Pourboghrat Farhang
Published: July 2021

Thermo-hydroforming (THF) process is a single-step process for thermoplastic composite forming, which has a great advantage in terms of the process time and mass production potential as compared to conventional processes. However, with THF processes, wrinkles and deformations are easily generated due to the process characteristics and process parameters. In this study, the matrix material was examined by considering viscoelasticity and changes in formability according to the forming speed. A numerical analysis of the THF composites was performed based on the preferred fiber orientation (PFO) analysis model, which considers the viscoelasticity of the matrix. The deformation change and molding possibility were examined according to various forming speeds. The viscoelastic PFO model showed better analysis efficiency and stability than the primitive PFO model. This analysis will help improve the process of forming thermoplastic composites.
Theoretical Analysis of Thin Film Evaporation in the Wicks of Loop Heat Pipes
Authors: Lin Bingyao , Li Nanxi , Wang Shiyue , Tao Leren , Xu Guangming , Wu Yinong
Published: July 2021

In this paper, a thin film evaporation model that includes expressions for energy, mass, and momentum conservation was established through the augmented Young–Laplace model. Based on this model, the effects of pore size and superheating on heat transfer during thin film evaporation were analyzed. The influence of the wick diameter of the loop heat pipe (LHP) on the critical heat flux of the evaporator is analyzed theoretically. The results show that pore size and superheating mainly influence evaporation through changes in the length of the transition film and intrinsic meniscus. The contribution of the transition film area is mainly reflected in the heat transfer coefficient, and the contribution of the intrinsic meniscus area is mainly apparent in the quantity of heat that is transferred. When an LHP evaporator is operating in a state of surface evaporation, a higher heat transfer coefficient can be achieved using a smaller pore size.
Shock Isolation Characteristics of a Bistable Vibration Isolator With Tunable Magnetic Controlled Stiffness
Authors: Yan Bo , Ling Peng , Zhou Yanlin , Wu Chuanyu , Zhang Wenming
Published: July 2021

This paper investigates the shock isolation characteristics of an electromagnetic bistable vibration isolator (BVI) with tunable magnetic controlled stiffness. The theoretical model of the BVI is established. The maximum acceleration ratio (MAR), maximum absolute displacement ratio (MADR), and maximum relative displacement ratio (MRDR) are introduced to evaluate the shock isolation performance of the BVI. The kinetic and potential energy are observed to further explore the performance of the BVI. The effects of the potential barrier, shape of potential well, and damping ratio on the BVI are discussed compared with the linear vibration isolators (LVIs). The results demonstrate that the intrawell oscillations and snap-through oscillations are determined by the excitation amplitude and duration time of main pulse. MADR and MRDR of the BVI are smaller than those of the LVI. The maximum acceleration peak amplitude of the BVI is far below that of the LVI, especially when the snap-through oscillation occurs. In brief, the proposed BVI has a better shock isolation performance than the LVI and has the potential to suppress the shock of space structures during the launch and on-orbit deploying process.
Black hole flyby
Authors: Szybka Sebastian J.
Published: July 2021

We calculate the minimum distance at which one may approach a black hole in a free flyby. It corresponds to r=4m for the Schwarzschild black hole for a probe that was non-relativistic at infinity. The problem is formulated in a way that is useful for teaching introductory general relativity.
Thermal equilibrium of an ideal gas in a free-floating box
Authors: Tremaine Scott , Kocsis Bence , Loeb Abraham
Published: July 2021

The equilibrium and fluctuations of an ideal gas in a rigid container are studied by every student of statistical mechanics. Here, we examine the less well-known case when the box is floating freely; in particular, we determine the fluctuations of the box in velocity and position due to interactions with the gas it contains. This system is a toy model for the fluctuations in velocity and position of a black hole surrounded by stars at the center of a galaxy. These fluctuations may be observable in nearby galaxies.
Masitinib is a broad coronavirus 3CL inhibitor that blocks replication of SARS-CoV-2
Authors: Drayman Nir , DeMarco Jennifer K. , Jones Krysten A. , Azizi Saara-Anne , Froggatt Heather M. , Tan Kemin , Maltseva Natalia Ivanovna , Chen Siquan , Nicolaescu Vlad , Dvorkin Steve , Furlong Kevin , Kathayat Rahul S. , Firpo Mason R. , Mastrodomenico Vincent , Bruce Emily A. , Schmidt Madaline M. , Jedrzejczak Robert , Muñoz-Alía Miguel Á. , Schuster Brooke , Nair Vishnu , Han Kyu-yeon , O’Brien Amornrat , Tomatsidou Anastasia , Meyer Bjoern , Vignuzzi Marco , Missiakas Dominique , Botten Jason W. , Brooke Christopher B. , Lee Hyun , Baker Susan C. , Mounce Bryan C. , Heaton Nicholas S. , Severson William E. , Palmer Kenneth E. , Dickinson Bryan C. , Joachimiak Andrzej , Randall Glenn , Tay Savaş
Published: July 2021

Targeting the main protease of SARS-CoV-2

Inside host cells, the RNA genome of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is translated into two polyproteins that are cleaved to give the individual viral proteins. The main viral protease, known as Mpro or 3CLpro, plays a key role in these cleavages, making it an important drug target. Drayman
et al
. identified eight drugs that target 3CLpro from a library of 1900 clinically safe drugs. Because of the challenge of working with SARS-CoV-2, they started by screening for drugs that inhibit the replication of a human coronavirus that causes the common cold. They then evaluated the top hits for inhibiting SARS-CoV-2 replication and for inhibiting 3CLpro. Masitinib, a broad antiviral, inhibited the main proteases of coronaviruses and picornaviruses and was effective in reducing SARS-CoV-2 replication in mice. —VV
Laramide structure of southeastern Arizona: Role of basement-cored uplifts in shallow-angle subduction
Authors: Favorito Daniel A. , Seedorff Eric
Published: July 2021

Laramide reverse faults in southeastern Arizona commonly are obscured by mid- to late Cenozoic extension and subsequent cover, resulting in debate about their configuration and origin. A new mid-Cenozoic paleogeologic map depicts the structural configuration before extension, and new structural reconstructions characterize Laramide shortening in terms of structural style, magnitude, evolution, and timing.

Reverse faults restore to moderate to high angles, are associated with fault-propagation folds, and involve significant basement and thus constitute thick-skinned deformation. The paleogeologic map suggests several major basement-cored block uplifts, many of which are newly identified. The largest uplifts may measure 150 km along strike, similar to those in the classic Laramide province of Wyoming and Colorado. Estimated shortening across the central study area is 14% or 23 km, whereas it is only 5% (9 km) to the north and 11% (12 km) to the south. Shortening by this mechanism is inadequate to explain previous estimates of crustal thickening in the region (∼50–60 km). Therefore, magmatic underplating, lower-crustal flow, or underplating of trench sediments and lithospheric material also may have contributed to thickening. Shortening largely occurred from 86 Ma to 64 Ma and possibly as late as 53 Ma, with initiation being younger to the northeast or north. Integration with data from southwestern New Mexico implies complex geometry for the subducting flat slab. Finally, reverse faults generally do not appear to have reactivated older faults, as previously suggested, primarily because reverse faults have associated fault-propagation folds in rocks that predate supposed reactivated structures.
InfantEscherichia coliurinary tract infection: is it associated with meningitis?
Authors: Rafferty Aisling , Drew Richard J , Cunney Robert , Bennett Désirée , Marriott John Francis
Published: July 2021

Objectives

Determine the prevalence of coexisting bacterial meningitis (BM) and sterile cerebrospinal fluid (CSF) with raised white cell count relative to age (‘pleocytosis’) in the presence ofEscherichia coliurinary tract infection (UTI), with the addition of CSFE. coliPCR analysis.

Design

Single-centre, retrospective cohort study.

Setting

Tertiary paediatric hospital.

Participants

Children aged 8 days to 2 years, with a pure growth ofE. colifrom urine and a CSF sample taken within 48 hours of a positive urine culture between 1 January 2014 and 30 April 2019.

Main outcome measure

Prevalence of coexistingE. coliBM with UTI, defined as a pure growthE. colifrom urine and a CSF culture with pure growthE. coliand/or positiveE. coliPCR.

Results

1903 patients had anE. coliUTI, of which 314 (16%) had a CSF sample taken within 48 hours. No cases of coexistingE. coliBM were identified. There were 71 (23%) cases of pleocytosis, 57 (80%) of these had PCR analysis, all of which wereE. coliPCR not detected. Patients aged 1–6 months accounted for 72% of all lumbar punctures (LPs).

Conclusion

The risk ofE. coliUTI and coexistingE. coliBM is low. There is potential to reduce the number of routine LPs in infants with a diagnosis ofE. coliUTI with the greatest impact in children up to 6 months of age. CSFE. coliPCR can help further reduce post-test probability of BM in the setting of pleocytosis.
Sequential contralateral facial nerve palsies following COVID-19 vaccination first and second doses
Authors: Burrows Abigail , Bartholomew Theo , Rudd James , Walker David
Published: July 2021

A 61-year-old man presented to the ENT emergency clinic with a history of unilateral facial nerve palsy occurring shortly after each dose of the Pfizer-BioNTech COVID-19 vaccine. The first episode developed 5 hours after administration of the first dose and the second 2 days after administration of the second dose. Investigations at initial presentation to the emergency department were unremarkable, and the patient was diagnosed with Bell’s palsy on both occasions. We describe the first case of Bell’s palsy occurring after each dose of any UK-approved COVID-19 vaccine. Single episodes of unilateral facial nerve palsies have been reported in clinical trials and in subsequent case reports. There has been no evidence, however, of an episode after each dose. We also describe the earliest onset of symptoms from timing of administration of the vaccine, further suggesting the Bell’s palsy was associated with the vaccine.
Laser goniopuncture after deep sclerectomy: incidence, long-term outcomes and risk factors for failure
Authors: Rabiolo Alessandro , Leadbetter Duncan , Kirk Jonathan , Anand Nitin
Published: July 2021

Aims

To report the incidence, risk factors and long-term outcomes of laser goniopuncture (LGP) in patients with previous deep sclerectomy (DS).

Methods

Retrospective cohort study of 1765 eyes (1385 patients) undergoing DS with or without cataract surgery between 2001 and 2020 in two UK institutions. Kaplan-Meier was used to estimate LGP incidence. DS success after LGP was calculated for criteria A, B, and C defined as intraocular pressure (IOP) of ≤18, ≤15 and ≤12 mm Hg with 20%, 25% and 30% reduction, respectively. Cox regression was used to investigate factors associated with the risk of failure.

Results

LGP had an estimated incidence of 33.3% (30.9%–35.6%), 56.3% (53.5%–58.9%) and 62.8% (59.7%–65.6%) at 1, 3, 5 years, respectively. Mean (±SD) IOP significantly (p<0.001) decreased from 21.2 (±6.0) mm Hg pre-LGP to 13.8 (±5.2) mm Hg and 12.9 (±4.7) mm Hg at 3 and 5 years post-LGP, respectively. Success rates at 3 and 5 years were, respectively, 40.9% (37.5%–44.6%) and 33.7% (30.3%–37.6%) for criterion A; 27.1% (24.0%–30.5%) and 22.3% (19.3%–25.7%) for criterion B and 13.9% (11.6%–16.7%) and 11.6% (9.5%–14.3%) for criterion C. In all models, higher pre-LGP IOP (p<0.001) and higher pre-LGP medication number (p<0.001) were associated with increased failure, while male gender (p≤0.004), intraoperative mitomycin C (p≤0.031), longer interval between DS and LGP (p≤0.01) with reduced failure.

Conclusion

Most patients undergoing DS will eventually require LGP. LGP is effective at rescuing eyes with a failing DS. This study identifies several factors associated with LGP outcomes, knowledge of which may help clinicians predict LGP success.
Sedation strategy and ICU delirium: a multicentre, population-based propensity score-matched cohort study
Authors: Casault Colin , Soo Andrea , Lee Chel Hee , Couillard Philippe , Niven Daniel , Stelfox Tom , Fiest Kirsten
Published: July 2021

Objectives

We examined the relationship between dominant sedation strategy, risk of delirium and patient-centred outcomes in adults admitted to intensive care units (ICUs).

Design

Retrospective propensity-matched cohort study.

Setting

Mechanically ventilated adults (≥ 18 years) admitted to four Canadian hospital medical/surgical ICUs from 2014 to 2016 in Calgary, Alberta, Canada.

Participants

2837 mechanically ventilated adults (≥ 18 years) requiring admission to a medical/surgical ICU were evaluated for the relationship between sedation strategy and delirium.

Interventions

None.

Primary and secondary outcome measures

The primary exposure was dominant sedation strategy, defined as the sedative infusion, including midazolam, propofol or fentanyl, with the longest duration before the first delirium assessment. The primary outcome was ‘ever delirium’ identified using the Intensive Care Delirium Screening Checklist. Secondary outcomes included mortality, length of stay (LOS), ventilation duration and days with delirium. The cohort was analysed in two propensity score (patient characteristics and therapies received) matched cohorts (propofol vs fentanyl and propofol vs midazolam).

Results

2837 patients (60.7% male; median age 57 years (IQR 43–68)) were considered for propensity matching. In propensity score-matched cohorts(propofol vs midazolam, n=712; propofol vs fentanyl, n=1732), the odds of delirium were significantly higher with midazolam (OR 1.46 (95% CI 1.06 to 2.00)) and fentanyl (OR 1.22 (95% CI 1.00 to 1.48)) compared with propofol dominant sedation strategies. Dominant sedation strategy with midazolam and fentanyl were associated with a longer duration of ventilation compared with propofol. Fentanyl was also associated with increased ICU mortality (OR 1.50, 95% CI 1.07 to 2.12)) ICU and hospital LOS compared with a propofol dominant sedation strategy.

Conclusions

We identified a novel association between fentanyl dominant sedation strategies and an increased risk of delirium, a composite outcome of delirium or death, duration of mechanical ventilation, ICU LOS and hospital LOS. Midazolam dominant sedation strategies were associated with increased delirium risk and mechanical ventilation duration.
Economic and social impacts of COVID-19 and public health measures: results from an anonymous online survey in Thailand, Malaysia, the UK, Italy and Slovenia
Authors: Osterrieder Anne , Cuman Giulia , Pan-Ngum Wirichada , Cheah Phaik Kin , Cheah Phee-Kheng , Peerawaranun Pimnara , Silan Margherita , Orazem Miha , Perkovic Ksenija , Groselj Urh , Schneiders Mira Leonie , Poomchaichote Tassawan , Waithira Naomi , Asarath Supa-at , Naemiratch Bhensri , Ruangkajorn Supanat , Skof Lenart , Kulpijit Natinee , Mackworth-Young Constance R S , Ongkili Darlene , Chanviriyavuth Rita , Mukaka Mavuto , Cheah Phaik Yeong
Published: July 2021

Objectives

To understand the impact of COVID-19 and public health measures on different social groups, we conducted a mixed-methods study in five countries (‘SEBCOV—social, ethical and behavioural aspects of COVID-19’). Here, we report the results of the online survey.

Study design and statistical analysis

Overall, 5058 respondents from Thailand, Malaysia, the UK, Italy and Slovenia completed the self-administered survey between May and June 2020. Poststratification weighting was applied, and associations between categorical variables assessed. Frequency counts and percentages were used to summarise categorical data. Associations between categorical variables were assessed using Pearson’s χ2test. Data were analysed in Stata 15.0

Results

Among the five countries, Thai respondents reported having been most, and Slovenian respondents least, affected economically. The following factors were associated with greater negative economic impacts: being 18–24 years or 65 years or older; lower education levels; larger households; having children under 18 in the household and and having flexible/no income. Regarding social impact, respondents expressed most concern about their social life, physical health, mental health and well-being.

There were large differences between countries in terms of voluntary behavioural change, and in compliance and agreement with COVID-19 restrictions. Overall, self-reported compliance was higher among respondents who self-reported a high understanding of COVID-19. UK respondents felt able to cope the longest and Thai respondents the shortest with only going out for essential needs or work. Many respondents reported seeing news perceived to be fake, the proportion varying between countries, with education level and self-reported levels of understanding of COVID-19.

Conclusions

Our data showed that COVID-19 and public health measures have uneven economic and social impacts on people from different countries and social groups. Understanding the factors associated with these impacts can help to inform future public health interventions and mitigate their negative consequences.

Trial registration number

TCTR20200401002.
Patient-reported impact of myasthenia gravis in the real world: protocol for a digital observational study (MyRealWorld MG)
Authors: Berrih-Aknin Sonia , Claeys Kristl G , Law Nancy , Mantegazza Renato , Murai Hiroyuki , Saccà Francesco , Dewilde Sarah , Janssen Mathieu F , Bagshaw Emma , Kousoulakou Hara , Larkin Mark , Beauchamp Jon , Leighton Trevor , Paci Sandra
Published: July 2021

Introduction

Myasthenia gravis (MG) is a rare, chronic, autoimmune disease, mediated by immunoglobulin G antibodies, which causes debilitating muscle weakness. As with most rare diseases, there is little patient-reported data with which to understand and address patient needs. This study explores the impact of MG in the real world from the patient perspective.

Methods and analysis

This is a 2-year prospective, observational, digital, longitudinal study of adults with MG, resident in the following countries: the USA, Japan, Germany, France, the UK, Italy, Spain, Canada and Belgium. The planned sample size is 2000. Recruitment will be community based, via patient advocacy groups, social media and word of mouth. Participants will use a smartphone application (app) to check eligibility, provide consent and contribute data. Planned data entry is as follows: (1) personal profile on enrollment—covering demographics, MG characteristics and previous care; (2) monthly event tracker—current treatments, healthcare visits, treatment-related adverse events, productivity losses; (3) monthly selection of validated generic and disease-specific patient-reported outcomes instruments: EQ-5D-5L, Myasthenia Gravis Activities of Daily Living, Myasthenia Gravis Quality of Life 15-item revised scale, Hospital Anxiety and Depression Scale and Health Utilities Index III. Analyses are planned for when the study has been running in most countries for approximately 6, 12, 18 and 24 months.

Ethics and dissemination

The study protocol has been reviewed and granted ethics approval by Salus IRB for participants resident in the following countries: Germany, the UK and the US. Local ethics approval is being sought for the following study countries: Belgium, Canada, France, Italy, Japan and Spain. Study results will be communicated to the public and participants via conference presentations and journal publications, as well as regular email, social media and in-application communication.

Trial registration number

NCT04176211.
Interrogating structural inequalities in COVID-19 mortality in England and Wales
Authors: Griffith Gareth J , Davey Smith George , Manley David , Howe Laura D , Owen Gwilym
Published: July 2021

Background

Numerous observational studies have highlighted structural inequalities in COVID-19 mortality in the UK. Such studies often fail to consider the hierarchical, spatial nature of such inequalities in their analysis, leading to the potential for bias and an inability to reach conclusions about the most appropriate structural levels for policy intervention.

Methods

We use publicly available population data on COVID-19-related mortality and all-cause mortality between March and July 2020 in England and Wales to investigate the spatial scale of such inequalities. We propose a multiscale approach to simultaneously consider three spatial scales at which processes driving inequality may act and apportion inequality between these.

Results

Adjusting for population age structure and number of local care homes we find highest regional inequality in March and June/July. We find finer grained within region inequality increased steadily from March until July. The importance of spatial context increases over the study period. No analogous pattern is visible for non-COVID-19 mortality. Higher relative deprivation is associated with increased COVID-19 mortality at all stages of the pandemic but does not explain structural inequalities.

Conclusions

Results support initial stochastic viral introduction in the South, with initially high inequality decreasing before the establishment of regional trends by June and July, prior to reported regionality of the ‘second-wave’. We outline how this framework can help identify structural factors driving such processes, and offer suggestions for a long-term, locally targeted model of pandemic relief in tandem with regional support to buffer the social context of the area.
Split-hand and split-limb phenomena in amyotrophic lateral sclerosis: pathophysiology, electrophysiology and clinical manifestations
Authors: Corcia Philippe , Bede Peter , Pradat Pierre-François , Couratier Philippe , Vucic Steve , de Carvalho Mamede
Published: July 2021

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder affecting the upper and lower motor neurons. A key clinical feature of ALS is the absence of accurate, early-stage diagnostic indicators. ‘Split-hand syndrome’ was first described in ALS at the end of the last century and a considerable body of literature suggests that the split-hand phenomenon may be an important clinical feature of ALS. Considering the published investigations, it is conceivable that the ‘split-hand syndrome’ results from the associated upper and lower motor neuron degeneration, whose interaction remains to be fully clarified. Additionally, other split syndromes have been described in ALS involving upper or lower limbs, with a nuanced description of clinical and neurophysiological manifestations that may further aid ALS diagnosis. In this review, we endeavour to systematically present the spectrum of the ‘split syndromes’ in ALS from a clinical and neurophysiology perspective and discuss their diagnostic and pathogenic utility.
Seismic performance assessment of RC columns with interlocking hoops
Authors: Kim Tae-Hoon
Published: July 2021

The aim of this study is to analytically assess the seismic performance of reinforced concrete (RC) columns with interlocking hoops using a novel damage index, and to provide data for developing next generation seismic design criteria. Interlocking hoops are used in rectangular or non-circular columns, the splices shall be located in the column interior. Seismic performance of RC columns is controlled by the level of confinement provided by transverse steel. Interlocking hoops are commonly used in RC columns because they can provide more effective confinement than rectangular hoops. Three RC interlocking columns were tested under a constant axial load and a cyclically reversed horizontal load. A computer program, Reinforced Concrete Analysis in Higher Evaluation System Technology (RCAHEST), is used to analyze RC structures. Novel damage indices aim to provide a means of numerically quantifying the performance level in RC columns with interlocking hoops sustained under earthquake loading. The proposed numerical method for the seismic performance assessment of interlocking columns is verified by comparison with the experimental results.
Strain-tunable electronic structure of two-dimensional monolayer SiP
Authors: Han Xiao , Meng Fan-Shun , Yan Xiao-Jie , Zhang Hui
Published: July 2021

The 2D monolayer [Formula: see text]-SiP has a honeycomb lattice and an intrinsic indirect band gap. Herein, the density functional theory calculations are performed to modulate the electronic structure of 2D monolayer [Formula: see text]-SiP by applying strains. The band gap of monolayer [Formula: see text]-SiP is monotonously reduced by the strains. More interestingly, a direct band gap is more likely to be achieved by applying strains along the armchair direction than along the zigzag direction. Finally, 2D monolayer [Formula: see text]-SiP can possess a tunable direct band gap of 1.57–0.73 eV (HSE06) and considerable visible light absorption index, by applying compression strains of −6–−10% along the armchair direction. The work provides a route of modulating the electronic and optical properties of monolayer [Formula: see text]-SiP, which extends its application range for various fields such as electronic devices and solar energy conversion.
Outcomes of Acute Operative Repair of Complete Digital Proximal Interphalangeal Joint Collateral Ligament Ruptures: A Systematic Review
Authors: Bui David , Jenkins Michael , Schick Bernard , Sivakumar Brahman Shankar
Published: July 2021

Background: No consensus exists regarding the management of complete collateral ligament injuries of the proximal interphalangeal joint (PIPJ) of fingers.

Methods: We aimed to systematically review the outcomes of Acute (< 1 month) surgical repairs of these injuries. Outcomes assessed included Stability, Pain, Range-of-Motion and Return to Function. The Modified Coleman Methodology Score (MCMS) was utilised in critical appraisal.

Results: 70 patients with complete collateral ligament injuries of the PIPJ were identified in 5 studies. 49 were managed operatively and 21 non-operatively. All trials were methodologically flawed with a mean MCMS of 50.4, corresponding to a “Poor” Level of evidence.

Conclusions: Whilst acute surgical repair of complete collateral ligament injuries of finger PIPJs are a described viable management option with promising results, there is insufficient high-quality evidence to inform current practice. Based on the current literature, no evidence-based conclusions can be made regarding superiority of acute surgical repair over conservative management or one method of surgical repair over another. Further high level studies are required.
Telemedicine during the COVID-19 Pandemic: A Hand Surgery Perspective
Authors: Moses Michael J. , Buchalter Daniel B. , Azad Ali , Hacquebord Jacques H. , Paksima Nader , Yang S. Steven
Published: July 2021

Background: A major consequence of the COVID-19 pandemic on the U.S. healthcare system has been the rapid transition away from in-person healthcare visits to telehealth. This study analyzed patient and surgeon satisfaction in the utilization of telehealth within the hand surgery division during the COVID-19 pandemic.

Methods: All hand surgery patients who completed a telemedicine visit from March 30th, 2020 through April 30th, 2020 completed a 14-question survey via e-mail. Hand surgeons who participated in telemedicine completed a separate 14-question survey. Survey results were presented descriptively (mean ± standard deviation) and patient factors influencing satisfaction were determined using univariate and multivariate proportional modeling.

Results: 89 patients and five surgeons completed the surveys. Patients were very satisfied with their telemedicine visits (4.21/5.00 ± 0.89). Multivariate proportional modeling determined patients who found it “very easy” (5/5) to arrange telemedicine visits had greater satisfaction (OR = 4.928; 95% CI = 0.94 to 25.84) compared to those who found it “difficult” (2/5) (p = 0.059). Patients who believed they could ask/relay questions/concerns “extremely effectively” (5/5) had greater satisfaction (OR = 55.236; CI = 11.39 to 267.80) compared to those who asked/relayed questions only “slightly effective” to “moderately effectively” (p < 0.001). Surgeons were similarly satisfied with their telemedicine experience (4.00/5.00 ± 0.89) and were confident in their diagnoses (4.20/5.00 ± 0.84). All surgeons responded they will continue using telemedicine. 30.7% of patients would choose telemedicine over an inperson visit.

Conclusions: Telemedicine provides a viable platform for healthcare delivery with high patient and surgeon satisfaction. Most patients still prefer in-person visits for the post-pandemic future.
QuanTaichi
Authors: Hu Yuanming , Liu Jiafeng , Yang Xuanda , Xu Mingkuan , Kuang Ye , Xu Weiwei , Dai Qiang , Freeman William T. , Durand Frédo
Published: July 2021

High-resolution simulations can deliver great visual quality, but they are often limited by available memory, especially on GPUs. We present a compiler for physical simulation that can achieve both high performance and significantly reduced memory costs, by enabling flexible and aggressive
quantization.
Low-precision ("quantized") numerical data types are used and packed to represent simulation states, leading to reduced memory space and bandwidth consumption. Quantized simulation allows higher resolution simulation with less memory, which is especially attractive on GPUs. Implementing a quantized simulator that has high performance and packs the data tightly for aggressive storage reduction would be extremely labor-intensive and error-prone using a traditional programming language. To make the creation of quantized simulation practical, we have developed a new set of language abstractions and a compilation system. A suite of tailored domain-specific optimizations ensure quantized simulators often run as fast as the full-precision simulators, despite the overhead of encoding-decoding the packed quantized data types. Our programming language and compiler, based on
Taichi
, allow developers to effortlessly switch between different full-precision and quantized simulators, to explore the full design space of quantization schemes, and ultimately to achieve a good balance between space and precision. The creation of quantized simulation with our system has large benefits in terms of memory consumption and performance, on a variety of hardware, from mobile devices to workstations with high-end GPUs. We can simulate with levels of resolution that were previously only achievable on systems with much more memory, such as multiple GPUs. For example, on a
single
GPU, we can simulate a Game of Life with 20 billion cells (8× compression per pixel), an Eulerian fluid system with 421 million active voxels (1.6× compression per voxel), and a hybrid Eulerian-Lagrangian elastic object simulation with 235 million particles (1.7× compression per particle). At the same time, quantized simulations create physically plausible results. Our quantization techniques are
complementary
to existing acceleration approaches of physical simulation: they can be used in combination with these existing approaches, such as sparse data structures, for even higher scalability and performance.
Guaranteed-quality higher-order triangular meshing of 2D domains
Authors: Mandad Manish , Campen Marcel
Published: July 2021

We present a guaranteed quality mesh generation algorithm for the curvilinear triangulation of planar domains with piecewise polynomial boundary. The resulting mesh consists of higher-order triangular elements which are not only regular (i.e., with injective geometric map) but respect strict bounds on quality measures like scaled Jacobian and MIPS distortion. This also implies that the curved triangles' inner angles are bounded from above and below. These are key quality criteria, for instance, in the field of finite element analysis. The domain boundary is reproduced exactly, without geometric approximation error. The central idea is to transform the curvilinear meshing problem into a linear meshing problem via a carefully constructed transformation of bounded distortion, enabling us to leverage key results on guaranteed-quality straight-edge triangulation. The transformation is based on a simple yet general construction and observations about convergence properties of curves under subdivision. Our algorithm can handle arbitrary polynomial order, arbitrarily sharp corners, feature and interface curves, and can be executed using rational arithmetic for strict reliability.
End-to-end complex lens design with differentiate ray tracing
Authors: Sun Qilin , Wang Congli , Fu Qiang , Dun Xiong , Heidrich Wolfgang
Published: July 2021

Imaging systems have long been designed in separated steps: experience-driven optical design followed by sophisticated image processing. Although recent advances in computational imaging aim to bridge the gap in an end-to-end fashion, the image formation models used in these approaches have been quite simplistic, built either on simple wave optics models such as Fourier transform, or on similar paraxial models. Such models only support the optimization of a single lens surface, which limits the achievable image quality.

To overcome these challenges, we propose a general end-to-end complex lens design framework enabled by a differentiable ray tracing image formation model. Specifically, our model relies on the differentiable ray tracing rendering engine to render optical images in the full field by taking into account all on/off-axis aberrations governed by the theory of geometric optics. Our design pipeline can jointly optimize the lens module and the image reconstruction network for a specific imaging task. We demonstrate the effectiveness of the proposed method on two typical applications, including large field-of-view imaging and extended depth-of-field imaging. Both simulation and experimental results show superior image quality compared with conventional lens designs. Our framework offers a competitive alternative for the design of modern imaging systems.
ROSEFusion
Authors: Zhang Jiazhao , Zhu Chenyang , Zheng Lintao , Xu Kai
Published: July 2021

Online reconstruction based on RGB-D sequences has thus far been restrained to relatively slow camera motions (<1m/s). Under very fast camera motion (e.g., 3m/s), the reconstruction can easily crumble even for the state-of-the-art methods. Fast motion brings two challenges to depth fusion: 1) the high nonlinearity of camera pose optimization due to large inter-frame rotations and 2) the lack of reliably trackable features due to motion blur. We propose to tackle the difficulties of fast-motion camera tracking in the absence of inertial measurements using random optimization, in particular, the Particle Filter Optimization (PFO). To surmount the computation-intensive particle sampling and update in standard PFO, we propose to accelerate the randomized search via updating a particle swarm template (PST). PST is a set of particles pre-sampled uniformly within the unit sphere in the 6D space of camera pose. Through moving and rescaling the pre-sampled PST guided by swarm intelligence, our method is able to drive tens of thousands of particles to locate and cover a good local optimum extremely fast and robustly. The particles, representing candidate poses, are evaluated with a fitness function defined based on depth-model conformance. Therefore, our method, being depth-only and correspondence-free, mitigates the motion blur impediment as (ToF-based) depths are often resilient to motion blur. Thanks to the efficient template-based particle set evolution and the effective fitness function, our method attains good quality pose tracking under fast camera motion (up to 4m/s) in a realtime framerate without including loop closure or global pose optimization. Through extensive evaluations on public datasets of RGB-D sequences, especially on a newly proposed benchmark of fast camera motion, we demonstrate the significant advantage of our method over the state of the arts.
High-order differentiable autoencoder for nonlinear model reduction
Authors: Shen Siyuan , Yang Yin , Shao Tianjia , Wang He , Jiang Chenfanfu , Lan Lei , Zhou Kun
Published: July 2021

This paper provides a new avenue for exploiting deep neural networks to improve physics-based simulation. Specifically, we integrate the classic Lagrangian mechanics with a deep autoencoder to accelerate elastic simulation of deformable solids. Due to the inertia effect, the dynamic equilibrium cannot be established without evaluating the second-order derivatives of the deep autoencoder network. This is beyond the capability of off-the-shelf automatic differentiation packages and algorithms, which mainly focus on the gradient evaluation. Solving the nonlinear force equilibrium is even more challenging if the standard Newton's method is to be used. This is because we need to compute a third-order derivative of the network to obtain the variational Hessian. We attack those difficulties by exploiting complex-step finite difference, coupled with reverse automatic differentiation. This strategy allows us to enjoy the convenience and accuracy of complex-step finite difference and in the meantime, to deploy complex-value perturbations as collectively as possible to save excessive network passes. With a GPU-based implementation, we are able to wield deep autoencoders (e.g., 10+ layers) with a relatively high-dimension latent space in real-time. Along this pipeline, we also design a sampling network and a weighting network to enable
weight-varying
Cubature integration in order to incorporate nonlinearity in the model reduction. We believe this work will inspire and benefit future research efforts in nonlinearly reduced physical simulation problems.
Editable free-viewpoint video using a layered neural representation
Authors: Zhang Jiakai , Liu Xinhang , Ye Xinyi , Zhao Fuqiang , Zhang Yanshun , Wu Minye , Zhang Yingliang , Xu Lan , Yu Jingyi
Published: July 2021

Generating free-viewpoint videos is critical for immersive VR/AR experience, but recent neural advances still lack the editing ability to manipulate the visual perception for large dynamic scenes. To fill this gap, in this paper, we propose the first approach for editable free-viewpoint video generation for large-scale view-dependent dynamic scenes using only 16 cameras. The core of our approach is a new layered neural representation, where each dynamic entity, including the environment itself, is formulated into a spatio-temporal coherent neural layered radiance representation called ST-NeRF. Such a layered representation supports manipulations of the dynamic scene while still supporting a wide free viewing experience. In our ST-NeRF, we represent the dynamic entity/layer as a continuous function, which achieves the disentanglement of location, deformation as well as the appearance of the dynamic entity in a continuous and self-supervised manner. We propose a scene parsing 4D label map tracking to disentangle the spatial information explicitly and a continuous deform module to disentangle the temporal motion implicitly. An object-aware volume rendering scheme is further introduced for the re-assembling of all the neural layers. We adopt a novel layered loss and motion-aware ray sampling strategy to enable efficient training for a large dynamic scene with multiple performers, Our framework further enables a variety of editing functions, i.e., manipulating the scale and location, duplicating or retiming individual neural layers to create numerous visual effects while preserving high realism. Extensive experiments demonstrate the effectiveness of our approach to achieve high-quality, photo-realistic, and editable free-viewpoint video generation for dynamic scenes.
Discrete conformal equivalence of polyhedral surfaces
Authors: Gillespie Mark , Springborn Boris , Crane Keenan
Published: July 2021

This paper describes a numerical method for surface parameterization, yielding maps that are locally injective and discretely conformal in an exact sense. Unlike previous methods for discrete conformal parameterization, the method is guaranteed to work for any manifold triangle mesh, with no restrictions on triangulatiothat each task can be formulated as a convex problem where the triangulation is allowed to change---we complete the picture by introducing the machinery needed to actually construct a discrete conformal map. In particular, we introduce a new scheme for tracking correspondence between triangulations based on
normal coordinates
, and a new interpolation procedure based on layout in the
light cone.
Stress tests involving difficult cone configurations and near-degenerate triangulations indicate that the method is extremely robust in practice, and provides high-quality interpolation even on meshes with poor elements.
Unified particle system for multiple-fluid flow and porous material
Authors: Ren Bo , Xu Ben , Li Chenfeng
Published: July 2021

Porous materials are common in daily life. They include granular material (e.g. sand) that behaves like liquid flow when mixed with fluid and foam material (e.g. sponge) that deforms like solid when interacting with liquid. The underlying physics is further complicated when multiple fluids interact with porous materials involving coupling between rigid and fluid bodies, which may follow different physics models such as the Darcy's law and the multiple-fluid Navier-Stokes equations. We propose a unified particle framework for the simulation of multiple-fluid flows and porous materials. A novel virtual phase concept is introduced to avoid explicit particle state tracking and runtime particle deletion/insertion. Our unified model is flexible and stable to cope with multiple fluid interacting with porous materials, and it can ensure consistent mass and momentum transport over the whole simulation space.
PH-CPF
Authors: Pluta Kacper , Edelstein Michal , Vaxman Amir , Ben-Chen Mirela
Published: July 2021

We present a new approach for computing planar hexagonal meshes that approximate a given surface, represented as a triangle mesh. Our method is based on two novel technical contributions. First, we introduce
Coordinate Power Fields
, which are a pair of tangent vector fields on the surface that fulfill a certain
continuity
constraint. We prove that the fulfillment of this constraint guarantees the existence of a seamless parameterization with quantized rotational jumps, which we then use to regularly remesh the surface. We additionally propose an optimization framework for finding Coordinate Power Fields, which also fulfill additional constraints, such as alignment, sizing and bijectivity. Second, we build upon this framework to address a challenging meshing problem: planar hexagonal meshing. To this end, we suggest a combination of conjugacy, scaling and alignment constraints, which together lead to planarizable hexagons. We demonstrate our approach on a variety of surfaces, automatically generating planar hexagonal meshes on complicated meshes, which were not achievable with existing methods.
Fast median filters using separable sorting networks
Authors: Adams Andrew
Published: July 2021

Median filters are a widely-used tool in graphics, imaging, machine learning, visual effects, and even audio processing. Currently, very-small-support median filters are performed using sorting networks, and large-support median filters are handled by
O
(1) histogram-based methods. However, the constant factor on these
O
(1) algorithms is large, and they scale poorly to data types above 8-bit integers. On the other hand, good sorting networks have not been described above the 7 X 7 case, leaving us with no fast way to compute integer median filters of modest size, and no fast way to compute floating point median filters for any size above 7 X 7.

This paper describes new sorting networks that efficiently compute median filters of arbitrary size. The key idea is that these networks can be factored to exploit the separability of the sorting problem - they share common work across scanlines, and within small tiles of output. We also describe new ways to run sorting networks efficiently, using a sorting-specific instruction set, compiler, and interpreter.

The speed-up over prior work is more than an order of magnitude for a wide range of data types and filter sizes. For 8-bit integers, we describe the fastest median filters for all sizes up to 25 X 25 on CPU, and up to 33 X 33 on GPU. For higher-precision types, we describe the fastest median filters at all sizes tested on both CPU and GPU.
Learning a family of motor skills from a single motion clip
Authors: Lee Seyoung , Lee Sunmin , Lee Yongwoo , Lee Jehee
Published: July 2021

We present a new algorithm that learns a parameterized family of motor skills from a single motion clip. The motor skills are represented by a deep policy network, which produces a stream of motions in physics simulation in response to user input and environment interaction by navigating continuous action space. Three novel technical components play an important role in the success of our algorithm. First, it explicitly constructs motion parameterization that maps action parameters to their corresponding motions. Simultaneous learning of motion parameterization and motor skills significantly improves the performance and visual quality of learned motor skills. Second, continuous-time reinforcement learning is adopted to explore temporal variations as well as spatial variations in motion parameterization. Lastly, we present a new automatic curriculum generation method that explores continuous action space more efficiently. We demonstrate the flexibility and versatility of our algorithm with highly dynamic motor skills that can be parameterized by task goals, body proportions, physical measurements, and environmental conditions.