Publication Trends on Mitophagy in the World and China: A 16-Year Bibliometric Analysis

In the past 16 years, research on mitophagy has increasingly expanded to a wider range of subjects. Therefore, comprehensively analyzing the relevant progress and development trends on mitophagy research requires specific methods. To assess the hotspots, directions, and quality of results in this field worldwide, we used multiple tools to examine research progress and growing trends in research on the matter during the last 16 years (from 2005 to 2020). We also compared the quantity and quality of the literature records on mitophagy published by research institutions in China and other developed countries, reviewed China’s contribution, and examined the gap between China and these developed countries. According to the results of our bibliometric analysis, the United States and its research institutes published the most papers. We identified cell biology as the most commonly researched subject on mitophagy and AUTOPHAGY as the most popular journal for research on mitophagy. We also listed the most cited documents from around the world and China. With gradually increased funding, China is progressively becoming prominent in the field of mitophagy; nevertheless, the gap between her and major countries in the world must be closed.

Evaluation of Newly Introduced Bioactive Materials in Terms of Cavity Floor Adaptation: OCT Study

OBJECTIVE

The aim of the present study was to evaluate the adaptation of newly introduced bioactive restorative materials to the cavity floor using cross-polarization optical coherence tomography (CP-OCT).

MATERIALS AND METHODS

Round class V cavities were prepared on the proximal surfaces of sixty non-carious human anterior teeth (0.5 mm depth × 4 mm diameter), which were divided into groups according to the restorative material (n = 15). In the VF group, Vertise flow composite (Kerr, Orange, CA, USA) was used, in the BF group, Beautifil II composite (Shofu, Koyoto, Japan) was used, and in the AB group, ACTIVA BioACTIVE composite (Pulpdent, Watertown, NY, USA) was used. Cavities were restored using the bulk filling technique and cured according to the manufacturers' instructions. Then, the specimens were immersed in a contrasting agent, and image acquisitions were taken by CP-OCT to calculate the adaptation percentage by using an image analysis software.

RESULTS

B-scans showed a diffuse bright band of white pixels at the tooth-resin interface that was interpreted as a micro-gap present between the cavity floor and restorative material. The Kruskal-Wallis test showed a statistically significant difference between all tested groups with the AB group representing the least gap formation, followed by the BF group, and then the VF group, which demonstrated the highest gap formation.

CONCLUSIONS

In class V cavities, better adaptation to the cavity floor can be obtained when using ACTIVA BioACTIVE more than Vertise flow and Beautifil II composites. In addition, CP-OCT is considered a non-destructive imaging tool that helps in evaluating the quality of the tooth-restoration interface when bioactive composites are used.

The Impact of Local Economic Growth Target Setting on the Quality of Public Occupational Health: Evidence From Provincial and City Government Work Reports in China

This article uses data from the government work reports of 31 provinces (autonomous regions and municipalities) in China and 21 cities in Guangdong Province of China to perform a fixed effect regression. It was found that economic growth target constraints and economic growth target gaps between countries and provinces, or between provinces and cities have a significant impact on the quality of public occupational health. The non-linear relationship between economic growth target setting and the quality of public occupational health was then discussed in detail, and the reliability of basic conclusions drawn was ensured by robustness and endogeneity tests. The results show that the effect of economic growth target constraints and gaps on the quality of public occupational health shows a “U-shaped” trend at both the provincial and city levels, which initially promotes and, eventually, inhibits. This relationship is closely related to the current economic system reforms, administrative reforms, and social transformation in China. Therefore, in emphasising high-quality economic development, the government should fully consider the actual state of the development of jurisdictions in setting economic goals to improve the quality of public occupational health in an orderly manner.

Management of neuropathic pain in patients with diabetic peripheral neuropathy and low back pain in Saudi Arabia: Evidence and gaps

We report existing evidence and gaps in neuropathic pain management in Saudi Arabia, the prevalence and patient management stages in diabetic peripheral neuropathy (DPN) and low back pain (LBP) with a neuropathic component. A semi-systematic approach was adopted to identify data on neuropathic pain. A structured search was conducted through MEDLINE, Embase, and BIOSIS databases to identify articles published in English between January 2010 and December 2019. Unstructured search was conducted through various sources including Google Scholar and Saudi Arabia's Ministry of Health website. Studies including populations ≥18 years and neuropathic pain were included; data gaps were supplemented with anecdotal data from local experts. Weighted or simple means were calculated for overall data; synthesized evidence was represented as an evidence gap map. Of 37 articles retrieved from structured search, none were eligible for final analyses. Thirteen articles from unstructured search and two anecdotal data sources were included for final analyses. The majority of articles included were of cross-sectional design (n = 10) in diabetes patients. The mean (range; number of articles) DPN prevalence was estimated as 33.6% (5.6%-65.3%; n = 8). Data on DPN patient management stages were limited; synthesized evidence indicated that 37.2% (0.41%-80.0%; n = 3) of patients had DPN awareness, 17.8% (n = 1) underwent screening, 22.4% (18.4%-65.3%; n = 2) had DPN diagnosis, and 45.1% (0.0%-62.7%; n = 2) received treatment for pain management. Data on LBP with neuropathic component were scarce (prevalence, 41.0% [n = 1]; diagnosis, 54.7% [n = 1]). Data are limited, so more studies are needed to accurately estimate the prevalence and stages of patient management for neuropathic pain in the country.

Influence of Embedded Gap and Overlap Fiber Placement Defects on Interlaminar Properties of High Performance Composites

Automated fiber placement (AFP), once limited to aerospace, is gaining acceptance and offers great potential for marine structures. This paper describes the influence of manufacturing defects, gaps, and overlaps, on the out-of-plane properties of carbon/epoxy composites manufactured by AFP. Apparent interlaminar shear strength measured by short beam shear tests was not affected by the presence of defects. However, the defects do affect delamination propagation. Under Mode I (tension) loading a small crack arrest effect is noted, resulting in higher apparent fracture energies, particularly for specimens manufactured using a caul plate. Under Mode II (in-plane shear) loading there is a more significant effect with increased fracture resistance, as stable propagation for specimens with small gaps changes to arrest with unstable propagation for larger gaps.

Gap Confinement Effect of a Tandem Nanochannel System and Its Application in Salinity Gradient Power Generation

As an important nanofluidic device, an artificial ion nanochannel could selectively transport ions inside its nanoconfinement space and the surface charge of the pore wall. Here, confinement effects were realized by tandem nanochannel units, which kept their cascade gaps less than 500 nm. Within these gaps, ionic conductance was governed by the surface charge density of the channel unit. Cations could be sufficiently selected and enriched within this confined space, which improves the cation transfer number of the system. Therefore, the tandem nanochannel system could greatly improve the diffusion potential and energy conversion efficiency in the salinity gradient power generation process. Poisson-Nernst-Planck equations were introduced to numerically simulate the ionic transport behavior and confirmed the experimental results. Finally, the gap confinement effect was introduced in the porous cellulose acetate membrane tandem nanochannel system, and a high output power density of 4.72 W/m² and energy conversion efficiency of 42.22% were achieved under stacking seven channel units.

Disparities in Cancer-Related Avoidable Mortality by the Level of Area Deprivation in South Korea

Background: This study investigated trends in cancer-related avoidable (preventable and treatable) mortality and its association with area deprivation in Korea. Methods: Cancer-related avoidable mortality rates per 100,000 population between 2015 and 2019 were measured using the Causes of Death Statistics. Area Deprivation Index (ADI) was measured from the Population and Housing Census and information on other independent variables from the Korea Community Health Survey. The gap in avoidable mortality between the more and less deprived groups was expressed as rate ratios (RR) and absolute differences (ADs) with a 95 percent confidence interval (95% CI). The association between avoidable mortality and ADI was investigated through Poisson regression modelling. Results: The more deprived areas had higher avoidable (RR 1.15, 95% CI 1.13–1.17; AD 6.58, 95% CI 5.59–7.57) and preventable (RR 1.19, 95% CI 1.17–1.21; AD 6.22, 95% CI 5.38–7.06) mortality. The overall cancer-related avoidable mortality decreased but the gap between the more and less deprived groups did not decline significantly during the study period. The association between avoidable and preventable mortality and area deprivation remained significant after adjusting for variables, including area levels of smokers and alcohol drinkers. Conclusions: The gap in avoidable mortality signifies the importance of addressing related disparities in cancer.

Missed, mistaken, stalled: Identifying components of delay to diagnosis in epilepsy

A substantial proportion of individuals with newly diagnosed epilepsy report prior seizures, suggesting a missed opportunity for early epilepsy care and management. Consideration of the causes and outcomes of diagnostic delay is needed to address this issue. We aimed to review the literature pertaining to delay to diagnosis of epilepsy, describing the components, characteristics, and risk factors for delay. We undertook a systematic search of the literature for full-length original research papers with a focus on diagnostic delay or seizures before diagnosis, published 1998-2020. Findings were collated, and a narrative review was undertaken. Seventeen papers met the inclusion criteria. Studies utilized two measures of diagnostic delay: seizures before diagnosis and/or a study-defined time between first seizure and presentation/diagnosis. The proportion of patients with diagnostic delay ranged from 16% to 77%; 75% of studies reported 38% or more to be affected. Delays of 1 year or more were reported in 13%-16% of patients. Seizures prior to diagnosis were predominantly nonconvulsive, and usually more than one seizure was reported. Prior seizures were often missed or mistaken for symptoms of other conditions. Key delays in the progression to specialist review and diagnosis were (1) "decision delay" (the patient's decision to seek/not seek medical review), (2) "referral delay" (delay by primary care/emergency physician referring to specialist), and (3) "attendance delay" (delay in attending specialist review). There were few data available relevant to risk factors and virtually none relevant to outcomes of diagnostic delay. This review found that diagnostic delay consists of several components, and progression to diagnosis can stall at several points. There is limited information relating to most aspects of delay apart from prevalence and seizure types. Risk factors and outcomes may differ according to delay characteristics and for each of the key delays, and recommendations for future research include examining each before consideration of interventions is made.

Value-Based Pay-for-Performance Gaps in the Care Delivery Framework for a Large-Scale Health System

Many health systems are engaging in pay-for-performance agreements with payers that focus primarily on improving ambulatory preventive screenings. These also are referred to as gaps in care. Gaps in care are typically measured by the Healthcare Effectiveness Data and Information Set measures of health care quality. To address gaps in care effectively, the physician-led Gaps in Care program at Northwell Health works to improve processes related to measurement, data attribution, patient outreach, and patient engagement. Following a structured framework to address patient gaps in care is a successful strategy for accomplishing complex value-based care delivery.

Comparative Accuracy of 1.5T MRI, 3T MRI, and Static Ultrasound in Diagnosis of Small Gaps in Repaired Flexor Tendons: A Cadaveric Study

PURPOSE

We hypothesized that magnetic resonance imaging (MRI) would more accurately diagnose small gaps (<6 mm) after flexor tendon repair than static ultrasound (US) and that suture artifact would negatively impair accuracy.

METHODS

A laceration of the flexor digitorum profundus was created in 160 fresh-frozen cadaveric digits and randomized to either an intact repair (0-mm gap) or repairs using a locked 4-strand suture repair with either 4-0 Prolene, Ethibond, or and gaps of 2, 4,or 6 mm; or no suture in which 2-, 4-, or 6-mm gaps were created without a suture crossing the repair site. We performed 1.5T and 3T MRI and static US studies; gap widths were estimated by radiologists blinded to suture presence and true gap widths.

RESULTS

The 1.5 and 3.0T MRI had a lower mean error than US for gap sizes 0 and 2 mm. All 3 modalities performed similarly for 4- and 6-mm gaps. Documentation of imaging artifact worsened error, and odds of seeing artifacts were 1.72 higher with MRI than with US. Suture did not worsen artifact nor impair accuracy for any of the 3 modalities. When no suture was used, all 3 modalities significantly overestimated the true gap.

CONCLUSIONS

MRI is most accurate for small gaps less than 4 mm. Although all modalities overestimated gap sizes in specimens with a 0-mm gap (intact tendon repair), mean overestimation (<2 mm) was not clinically relevant. Ultrasound overestimated 2-mm gaps (clinically intact repairs), whereas MRIs did not. We recommend MRI for evaluation of gaps after flexor tendon repair. The 1.5T has slightly better sensitivity and specificity for distinguishing clinically intact (gap < 3 mm) from clinically impaired (gap > 3 mm) repairs than the 3T.

CLINICAL RELEVANCE

Accurate diagnosis of intact repairs or small gaps (<3 mm) might prevent unnecessary exploration or allow modification of rehabilitation protocols. Diagnosis of clinically relevant gaps (3-6 mm) may allow for earlier revision surgery before significant tendon retraction and adhesions develop, possibly necessitating a staged reconstruction.

Gap or prehistoric monster? A history of the humanitarian-development nexus at UNICEF

Why has bridging the humanitarian-development divide been such a long-running endeavour, and why have so many frameworks to do so been proposed and picked apart over the years? Rather than contributing yet another 'mind the gap' approach, this paper seeks to articulate why such a lacuna emerged in the first place, and to explore how to exit a debate that has grown increasingly circular. To provide one possible answer to the questions above, the paper draws on the history of UNICEF (United Nations Children's Fund) in working across the 'humanitarian-development' nexus. Suggesting that the gap is more artefact than fact, derived from the institutionalisation of aid, the paper argues that focusing on the challenges and the concepts that inherently transcend humanitarian-development silos may enhance understanding of what it means-and what is needed-to operate at the intersection of humanitarian and development action on behalf of children.

Paediatric tuberculosis - new advances to close persistent gaps

Young children are most vulnerable to develop severe forms of tuberculosis (TB) and are over-represented among TB deaths. Almost all children estimated to have died from TB were never diagnosed or offered TB treatment. Improved access to TB preventive treatment (TPT) requires major upscaling of household contact investigation with allocation of adequate resources. Symptom-based screening is often discouraged in adults for fear of generating drug resistance, if TB cases are missed. However, the situation in vulnerable young children is different, as they present minimal risk of drug resistance generation. Further, the perceived need for additional diagnostic evaluation presents a major barrier to TPT access and underlies general reluctance to consider pragmatic decentralised models of care. Widespread roll-out of Xpert MTB/RIF Ultra® represents an opportunity for improved case detection in young children, but attaining full impact will require the use of non-sputum specimens. The new Fujifilm SILVAMP TB LAM® urine assay demonstrated good diagnostic accuracy in HIV-positive and malnourished children, but further validation is required. Given the limited accuracy of all available tests and the excellent tolerance of TB drugs in children, the global community may have to accept some over-treatment if we want to close the persistent case detection gap in young children.

Comparative Sensitivity and Specificity of Static and Dynamic High-Resolution Ultrasound in Diagnosis of Small Gaps in Repaired Flexor Tendons: A Cadaveric Study

PURPOSE

To compare the sensitivity and specificity of high-resolution static and dynamic ultrasound (US) for diagnosing intact repairs and small, clinically relevant gaps (≥4 mm) in repaired flexor digitorum profundus tendons within zone 2 and, secondarily, to evaluate the effect of suture artifact from 3 commonly used suture types.

METHODS

Eighty-eight fresh-frozen cadaveric digits (thumbs excluded) were randomized to either an intact repair (0-mm gap) or repairs using a locked 4-strand suture repair with either 4-0 Prolene, Ethibond, or FiberWire and gaps of 2, 4, or 6 mm and no suture in which 2-, 4-, or 6-mm gaps were created without a suture crossing the repair site. Gap widths were estimated by a blinded musculoskeletal ultrasonographer in static and dynamic modes.

RESULTS

Both static and dynamic modalities tended to overestimate actual gap sizes. For the suture gaps, both modalities had poor sensitivity (29% static; 42% dynamic) for accurately diagnosing a clinically intact repair (<4 mm), but better specificity (83% static; 75% dynamic) for diagnosing a clinically failed repair (≥4-mm gap). Although suture presence decreased the sensitivity of gap width measurement for both modalities, no differences were seen between suture types.

CONCLUSIONS

Static and dynamic US have poor sensitivity for diagnosing clinically intact repairs (gaps < 4 mm) because they typically overestimate gap size. The ability to diagnose failed repairs (gap ≥ 4 mm), based on greater specificity, is much better, but still suboptimal.

CLINICAL RELEVANCE

Based on a receiver operating characteristic analysis cutoff of 5 mm, if a gap of 5 mm or larger is identified with US when evaluating a zone 2 flexor digitorum profundus tendon repair, a failed repair is likely in about 80% of cases. A gap measurement of less than 5 mm may miss a high percentage of repairs that are clinically failed.

Optical comparison between micro-CT and OCT in imaging of marginal composite adaptation: Observational study

Dental composite is the most used aesthetic restorative biomaterial worldwide. However, it undergoes polymerisation shrinkage that could lead to loss of the interfacial seal between tooth and resin in some circumstances. This demands high-resolution imaging technologies to detect these defects. This study carried out a comparison between microcomputed tomography (micro-CT; Shimadzu, Japan) and swept-source optical coherence tomography (SS-OCT; Santec, Japan) in the detection of marginal adaptation defects at the tooth-resin interface. Unlike in micro-CT, it was possible to outline interfacial gaps along with tooth-resin interfaces with SS-OCT, which was attributed to the Fresnel diffraction of light. This in vitro comparison demonstrates SS-OCT has great potential in dental imaging to effectively assess dental composite adaptation and marginal defects when high resolution is desired in real time. LAY DESCRIPTION: Detection of tooth-colored restoration defects had been assessed by different radiographic methods. However, most of these methods are either invasive or suffer from low-resolution. In this study, a comparison has been carried out between two different high-resolution imaging systems; microcomputed tomography and optical coherence tomography, to explore their potentials in detecting restorations defects. The results showed optical coherence tomography has a great accuracy in locating the underlying defects when the obtained images were validated against confocal laser scanning microscopy images.

Sensitivity of express saccades to the expected value of the target

Express saccades, a distinct fast mode of visually guided saccades, are probably underpinned by a specific pathway that is at least partially different from the one underlying regular saccades. Whether and how this pathway deals with information on the subjective value of a saccade target is unknown. We studied the influence of varying reward expectancies and compared it with the impact of a temporal gap between the disappearance of the fixation dot and the appearance of the target on the visually guided saccades of two rhesus macaques (Macaca mulatta). We found that increasing reward expectancy increased the probability and decreased the reaction time of express saccades. The latter influence was stronger in the later parts of the reaction time distribution of express saccades, satisfactorily captured by a linear shift model of change in the saccadic reaction time distribution. Although different in strength, increasing reward expectancy and inserting a temporal gap resulted in similar effects on saccadic reaction times, suggesting that these two factors summon the same mechanism to facilitate saccadic reaction times.NEW & NOTEWORTHY Express saccades are the fastest visually driven way of shifting gaze to targets of interest. We examined whether the pathway underlying these saccades has access to information on the value of saccade targets. We found that not only regular saccades but also express saccades occur earlier in case of higher expectations of reward. Yet, the sensitivity of express saccades to reward decreases linearly when approaching the earliest possible reaction time.

Gender Compensation Gap for Ophthalmologists in the First Year of Clinical Practice

PURPOSE

To identify the role of gender and other factors in influencing ophthalmologists' compensation.

DESIGN

Cross-sectional study.

PARTICIPANTS

U.S. practicing ophthalmologists.

METHODS

Between January and March 2020, an anonymous survey was sent to U.S. residency program directors and practicing ophthalmologists who recently completed residency training. Respondents who completed residency ≤ 10 years ago and responded to questions about gender, fellowship training, state of practice, and salary were included. Propensity score match (PSM) analysis was performed with age, academic residency, top residency, fellowship, state median wage, practice type, ethnicity, and number of workdays. Multivariate linear regression (MLR) analysis controlled for additional factors along with the aforementioned variables.

MAIN OUTCOME MEASURES

Base starting salary with bonus (SWB) received in the first year of clinical position was the main outcome measure. A multiplier of 1.2 (20%) was added to the base salary to account for bonus.

RESULTS

Of 684 respondents, 384 (56% were female, 44% were male) from 68 programs were included. Female ophthalmologists received a mean initial SWB that was $33 139.80 less than that of their male colleagues (12.5%, P = 0.00). The PSM analysis showed an SWB difference of -$27 273.89 (10.3% gap, P = 0.0015). Additionally, SWB differences were calculated with the number of workdays substituted by operating room (OR) days (-$27 793.67 [10.5% gap, P = 0.0013]) and clinic days (-$23 597.57 [8.90% gap, P = 0.0064]) in separate PSM analyses. The SWB differences between genders were significant using MLR analyses, which also controlled for work, clinic, and OR days separately (-$22 261.49, $-18 604.65, and $-16 191.26, respectively; P = 0.017, P = 0.015, P = 0.002, respectively). Gender independently predicted income in all 3 analyses (P < 0.05). Although an association between gender and the attempt to negotiate was not detected, a greater portion of men subjectively reported success in negotiation (P = 0.03).

CONCLUSIONS

Female ophthalmologists earn significantly less than their male colleagues in the first year of clinical practice. Salary differences persist after controlling for demographic, educational, and practice type variables with MLR and PSM analyses. These income differences may lead to a substantial loss of accumulated earnings over an individual's career.

Achilles Tendon Rupture: Can the Tendon Gap on Ultrasound Scan Predict the Outcome of Functional Rehabilitation Program?

Background and objectives  There is a growing use of functional rehabilitation programs for the treatment of Achilles tendon rupture. Factors such as patient age and level of activity have been used to guide the decision. One of the debated indications is the gap size between the ruptured ends of the tendon. This study aims to define any correlation between the amount of the initial gap between tendon ends and patients outcome treated with the functional rehabilitation program. Method  A prospective case series study of all patients with acute Achilles tendon rupture treated non-surgically with the functional rehabilitation program between 2016 and 2018. The tendon gap was measured with an ultrasound scan on the initial presentation. Patients were followed for a minimum of 12 months and assessed for Achilles Tendon Rupture Score (ATRS), plantarflexion strength, and re-rupture rate.  Results  A total of 56 patients completed one-year follow-up, and 2 patients had re-ruptures. The mean plantar flexion gap was 13.7 mm. The mean ATRS at 12 months was 85.12. There was no statistically significant correlation between the final ATRS and the mean rupture gap. Conclusion  The outcome following non-operative functional rehabilitation treatment of rupture Achilles tendon did not correlate with the size of the tendon gap, and authors recommend that decision on functional rehabilitation should not be based on these criteria.

Is dermis fat arthroplasty better than plain gap arthroplasty? A prospective randomised controlled trial

The aim of the study was to compare interpositional arthroplasty using a dermis fat graft with gap arthroplasty in the management of ankylosis of the temporomandibular joint (TMJ). We organised a prospective randomised study of 22 patients who presented with ankylosis of the TMJ. They were randomised to be treated with either plain gap arthroplasty or dermis fat arthroplasty, and the predictor variable was the method of treatment. The primary outcome variables were mouth opening and pain on jaw exercises. Pain and interincisal opening were measured on day 5, day 14, at the end of one month, and at six months, one year, two years, and three years. There was a significant difference between the two groups on two occasions: postoperative day 5 (p=0.013) and at one year (p=0.018). The mean (SD) scores for mouth-opening were higher in the dermis fat group at all times (41.20 (4.69) mm compared with 39.50 (2.46) mm in gap arthroplasty at two years, and 41.40 (3.60) mm compared with 38.9 (2.02) mm at three years). The visual analogue pain scores were also lower in the dermis fat graft group. The groups showed similar results at the end of three years follow up, with no significant difference in mouth opening. We conclude therefore that the two techniques have similar outcomes in the management of ankylosis of the TMJ.

Intraoperative manipulation for flexion contracture during total knee arthroplasty

BACKGROUND

Joint gap unbalancing during total knee arthroplasty (TKA) induces flexion contracture. Flexion contracture is one of the most serious complications of TKA. When flexion contracture is found during surgery, intraoperative manipulation is often empirically performed. We evaluated the effects of intraoperative manipulation on joint gap and postoperative flexion contracture.

MATERIALS AND METHODS

TKA was performed for 136 knees. Intraoperative manipulation was performed for flexion contracture in 61 knees. Joint gap changes before and after manipulation were measured at six positions from extension to 120° of flexion. Manipulation was not performed for 75 knees. The extension angle was measured radiographically immediately after surgery, at 3 months, and 6 months postoperatively. Extension angles with manipulation and without manipulation were compared.

RESULTS

Joint gap changes (mm) before and after manipulation were 0.1, 0.0, -0.2, -0.3, -0.1, and -0.3 at 0°, 30°, 45°, 60°, 90°, and 120° of flexion, respectively, indicating that manipulation could not change joint gaps significantly. Extension angles (°) with and without manipulation were -4.0 ± 4.6 and -3.8 ± 3.9 immediately after surgery, -5.3 ± 6.7 and -5.5 ± 6.2 at 3 months postoperatively, and -2.7 ± 6.0 and -3.8 ± 5.8 at 6 months postoperatively. No statistically significant difference existed between the values with or without manipulation during all periods.

CONCLUSION

Intraoperative manipulation does not enlarge the gap or resolve postoperative flexion contracture. Developing the new surgical technique is required to achieve perfect balance at TKA.

Gaps present a trade-off between dispersal and establishment that nourishes species diversity

We took advantage of two natural experiments to investigate processes that regulate tree recruitment in gaps. In the first, we examined the recruitment of small and large saplings and trees into 31 gaps resulting from treefalls occurring between 1984 and 2015 in the 2.25-ha core area of a 4-ha tree plot at Cocha Cashu in Perú. In the second, we identified the tallest saplings recruiting into 69 gaps created during a violent wind storm in February 2000. In the established tree plot, we were able to compare the composition of saplings in the disturbance zones of gaps prior to, during, and subsequent to the period of gap formation. Recruitment in gaps was compared with that in "nofall" zones, areas within the plot that had not experienced a treefall at least since the early 1980s. Our results confirmed earlier findings that a consistently high proportion (~60%) of established saplings survived gap formation. Light demanding species, as proxied by mortality rates, recruited under all conditions, but preferentially during periods of gap formation, a pattern that was especially strong among gap pioneers. Similar results were noted, separately, for small and large saplings and trees recruiting at ≥10 cm dbh. One hundred percent of previously untagged trees recruiting into gaps in the first post-disturbance census were gap pioneers, suggesting rapid development. This conclusion was strongly supported in a follow-up survey taken of 69 gaps 19 months after they had been synchronously created in a wind storm. Ten species of gap pioneers, eight of which are not normally present in the advance regeneration, had attained heights of 6-10 m in 19 months. The 10 gap pioneers were dispersed, variously, by primates, bats, birds, and wind and reached maximum frequency in different-sized gaps (range <100 m² to >1,000 m² ). Both gap size and limited dispersal of zoochorous species into gaps serve as filters for establishment, creating a complex mosaic of conditions that enhances species diversity.

How Flat Is the Tibial Osteotomy in Total Knee Arthroplasty?

BACKGROUND

Cementless total knee arthroplasty has been developed to decrease the incidence of failure in younger and more active patients. However, failures are still more common in cementless versus cemented components. It is hypothesized that this is triggered by incomplete bone-tray contact. The present study compares the final contact area of a cementless tray as a function of the initial osteotomy flatness.

METHODS

Eight surgeons prepared 14 cadaveric knees for cementless total knee replacement using standard instrumentation. The topography of each osteotomy was captured with a laser scanner; 3-dimensional computer models of the surfaces were generated. After scanning each tibia, the surgeons implanted cementless tibial trays using a manual impactor. Each tibia was then dissected, embedded in mounting resin, and sectioned. The sectioned blocks were observed under stereomicroscopy to identify points of bone-tray contact which were incorporated into the 3-dimensional models. Maps were then generated illustrating depicting contacting and noncontacting areas.

RESULTS

The mean initial flatness of all specimens was 1.1 ± 0.35 mm. After impaction, 79.4% ± 0.3% of the surface had established bony contact. Of the noncontacting areas, 17.6% were within 0.3 mm of the tray. Only 2.6% of the surface was at distances reported to impede ingrowth. Noncontacting areas were typically located centrally. A trend in decreasing percent contact area with increased flatness tolerance was observed (R² = 0.605).

CONCLUSION

(1) There is an inverse correlation between the flatness of the tibial osteotomy and the percentage of the bony surface in contact with underside of the tibial tray. (2) Almost all tray-tibia contact is generated during implantation through flattening of elevated features on the tibial surface. (3) Gaps between the tray and the tibia are consistently located in the central regions of the osteotomy proximal to the medullary canal.

Influence of Narrow Femoral Implants on Intraoperative Soft Tissue Balance in Posterior-Stabilized Total Knee Arthroplasty

BACKGROUND

Narrow femoral implants were developed to improve fit and prevent overhang in primary total knee arthroplasty (TKA). We compared intraoperative soft tissue balance between standard and narrow implants in posterior-stabilized (PS) TKA.

METHODS

We enrolled 30 consecutive patients with varus osteoarthritis undergoing PS TKA using an image-free navigation system. Standard and narrow femoral trial implants were inserted, and their soft tissue balance was measured. Subgroup analysis, based on the actual implanted femoral implant, was performed to assess the influence of narrow implants on soft tissue balance.

RESULTS

Narrow trial group had significantly larger joint component gaps than standard trial group at all measured flexion angles, except at 60° (P < .05). For the standard implant cohort, narrow trial group had significantly larger joint component gaps than standard trial group at 30°, 120°, and 135° flexion (P < .05). For the narrow implant cohort, narrow trial group had significantly larger joint component gaps than standard trial group at all measured flexion angles, except at 0° and 60° (P < .05). Narrow trial group had significantly larger varus ligament balance than standard trial group at 45° and 60° flexion (P < .05). The varus angles for standard implants were comparable between groups; however, narrow trial group had significantly larger varus angles for narrow implants than standard trial group at 45°, 60°, and 120° flexion (P < .05).

CONCLUSION

The medial-lateral dimension and volume of the femoral component may influence intraoperative soft tissue balance in PS TKA. The effects may be greater when narrow implants are selected to avoid component overhang.

Gap Opening in Twisted Double Bilayer Graphene by Crystal Fields

Crystal fields occur due to a potential difference between chemically different atomic species. In van der Waals heterostructures such fields are naturally present perpendicular to the planes. It has been realized recently that twisted graphene multilayers provide powerful playgrounds to engineer electronic properties by the number of layers, the twist angle, applied electric biases, electronic interactions, and elastic relaxations, but crystal fields have not received the attention they deserve. Here, we show that the band structure of large-angle twisted double bilayer graphene is strongly modified by crystal fields. In particular, we experimentally demonstrate that twisted double bilayer graphene, encapsulated between hBN layers, exhibits an intrinsic band gap. By the application of an external field, the gaps in the individual bilayers can be closed, allowing to determine the crystal fields. We find that crystal fields point from the outer to the inner layers with strengths in the bottom/top bilayer [Formula: see text] = 0.13 V/nm ≈ [Formula: see text] = 0.12 V/nm. We show both by means of first-principles calculations and low energy models that crystal fields open a band gap in the ground state. Our results put forward a physical scenario in which a crystal field effect in carbon substantially impacts the low energy properties of twisted double bilayer graphene, suggesting that such contributions must be taken into account in other regimes to faithfully predict the electronic properties of twisted graphene multilayers.

The Effect of Posterior Tibial Slope on Joint Gap and Range of Knee Motion in Mobile-Bearing Unicompartmental Knee Arthroplasty

BACKGROUND

It is widely known that the posterior tibial slope (PTS) has an influence on the clinical outcome of arthroplasty. However, the influence of PTS on unicompartmental knee arthroplasty (UKA) is still not fully clear. The objective of this study is to reveal the effect PTS has on knee flexion and extension joint gap and the postoperative range of motion in mobile-bearing UKA. Moreover, we investigated an adequate PTS angle in mobile-bearing UKA.

METHODS

Oxford UKA was performed so that the flexion gap would be equal to the extension gap. Correlation between the gap value difference from 90° to 120° of the knee flexion and the PTS was evaluated. Correlation between postoperative range of motion and the PTS was also evaluated to find whether a small degree of PTS would cause knee flexion restriction.

RESULTS

The PTS had a moderate positive correlation with the flexion gap difference. However, the PTS had no correlation with the knee flexion angle both postoperative and 1 year after surgery.

CONCLUSION

It was suggested that the degree of the PTS should not be so large to avoid joint looseness throughout every knee angle. Increasing the degree of the PTS had the potential to dislocate the bearing. Since a small degree of the PTS does not have an influence on the clinical outcome, surgeons should aim to cut the tibia with a posterior slope of less than 7°.