The Air-Lift Technique for Improving Ease and Safety When Establishing the Modified Midanterior Portal in Hip Arthroscopy.

Hip arthroscopy continues to increase in popularity and has an ever-expanding range of indications; however, the steep learning curve introduces significant risk of iatrogenic chondrolabral injury when accessing the joint and establishing arthroscopic portals. This article presents a technique for establishing the modified midanterior portal and is particularly useful when the available space is tight. We present "the air-lift" as a safe and simple adjunct to standard portal creation when performing hip arthroscopy in the supine position.

Proximal Anterolateral Accessory Portal Use Improves Peripheral Compartment Access and Capsular Management with T-Capsulotomy.

One of the primary goals of hip arthroscopy for femoroacetabular impingement (FAI) syndrome is precise removal of pathologic FAI morphology while protecting and restoring the normal soft tissue anatomy. Adequate visualization is a key foundation of precise removal of FAI morphology and varying types of capsulotomies are frequently used to achieve necessary exposure. Anatomic and outcomes studies have influenced an increasing appreciation for repairing these capsulotomies. Thus one of the central technical challenges of hip arthroscopy is achieving both goals of capsule preservation and adequate visualization. Various techniques have been described, including suture-based capsule suspension, portal placement, and T-capsulotomy. The following technique describes how the proximal anterolateral accessory portal can be added to a capsule suspension and T-capsulotomy technique to improve visualization and facilitate repair.

Impact of a 1-Year Pediatric Emergency Medicine Training Program for International Medical Graduates.

OBJECTIVES: The Hospital for Sick Children in Toronto has offered a 1-year subspecialty residency training program in pediatric emergency medicine (PEM) to Canadian and internationally trained pediatricians and emergency physicians since 1993. The program is intended to support clinical service delivery while simultaneously offering a unique educational opportunity to Canadian and international physicians who desire 1 year of clinically focused training. We describe the experiences and career outcomes of participants who completed this program. METHODS: Two surveys were sent to the 68 individuals who completed the clinical fellowship program from its inception in 1993 until 2014. A blinded survey focused on the fellowship experience and subsequent career activities. A nonblinded survey subsequently determined whether participants had served as a medical director or training program director. RESULTS: Sixty of the 68 participants (88%) completed the blinded survey. Ninety-one percent were in practice in emergency medicine. Twenty-five percent of the participants were living in Canada, compared with 17% before completing the program. This net migration of 8% was not significant (P = 0.26). Thirty-six of the 50 participants (72%) who applied from outside Canada responded to the nonanonymous survey; 18 (50%) had served as an emergency department medical director, and 18 (50%) reported serving as a PEM training program director. CONCLUSIONS: Many participants attained leadership positions in PEM in countries outside of North America and/or participated in training program development. There was no significant change in the proportion of participants living in North America at the time of application compared with the time of survey completion.

Hybrid Transtibial Femoral Preparation for Transphyseal Anterior Cruciate Ligament Reconstruction: A Radiographic Comparison With the Transtibial and Anteromedial Portal Techniques.

BACKGROUND: Transphyseal anterior cruciate ligament (ACL) reconstruction remains the most commonly used technique for pubescent patients. The transtibial (TT) drilling technique creates vertical and central femoral tunnels to minimize the physeal area of injury at the expense of a nonanatomic femoral tunnel. The hybrid TT (HTT) technique offers the potential of an anatomic femoral position with tunnel geometry similar to that using the TT technique. PURPOSE/HYPOTHESIS: The purpose was to perform a radiographic comparison of the HTT technique with TT and anteromedial portal (AM) techniques in adolescent patients undergoing transphyseal ACL reconstruction. It was hypothesized that femoral tunnels created during HTT would be similar to TT tunnels but significantly more vertical and central than AM tunnels. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: We retrospectively screened primary transphyseal ACL reconstructions performed in adolescents at our institution between 2013 and 2019. The youngest 20 eligible patients were selected from each technique cohort: TT, AM, and HTT. Postoperative radiographs were assessed for the coronal femoral tunnel angle, as well as the location of the tunnel-physis penetration on the anteroposterior and lateral views. Physeal lesion surface area was calculated. Data were compared among the 3 groups using 1-way analysis of variance followed by pairwise comparisons. RESULTS: Included were 47 patients with a mean ± SD age of 14.3 ± 1.2 years (n = 9 with TT, 18 with AM, and 20 with HTT techniques). The coronal tunnel angle was significantly more vertical in the TT (60.7° ± 7.2°) and HTT (54.4° ± 5.7) groups as compared with the AM group (48.8° ± 5.9; P = .0037 and P = .02, respectively). There was no significant difference between the TT and HTT groups (P = .066). The only significant finding regarding femoral tunnel location was that the HTT tunnels (28.9% ± 4.8%) penetrated the physis more centrally than did the AM tunnels (20.0% ± 5.1%; P = .00002) on lateral radiographs. CONCLUSION: The HTT technique presents an option for transphyseal ACL reconstruction, with femoral tunnel obliquity and estimated physeal disruption similar to that of the TT technique and significantly less than that of the AM technique. The HTT technique also results in the most central physeal perforation of all techniques, predominantly in the sagittal plane.

The oldest peracarid crustacean reveals a Late Devonian freshwater colonization by isopod relatives.

Peracarida (e.g. woodlice and side-swimmers) are, together with their sister-group Eucarida (e.g. krill and decapods), the most speciose group of modern crustaceans, suggested to have appeared as early as the Ordovician. While eucarids' incursion onto land consists of mainly freshwater and littoral grounds, some peracarids have evolved fully terrestrial ground-crawling ecologies, inhabiting even our gardens in temperate regions (e.g. pillbugs and sowbugs). Their fossil record extends back to the Carboniferous and consists mainly of marine occurrences. Here, we provide a complete re-analysis of a fossil arthropod-Oxyuropoda-reported in 1908 from the Late Devonian floodplains of Ireland, and left with unresolved systematic affinities despite a century of attempts at identification. Known from a single specimen preserved in two dimensions, we analysed its anatomy using digital microscopy and multispectral macroimaging to enhance the contrast of morphological structures. The new anatomical characters and completeness of Oxyuropoda, together with a phylogenetic analysis with representatives of all major Eumalacostraca groups, indicate that Oxyuropoda is a crown peracarid, part of a clade including amphipods and isopods. As such, Oxyuropoda is the oldest known species Peracarida, and provides evidence that derived peracarids had an incursion into freshwater and terrestrial environments as early as the Famennian, more than 360 Ma.

Post-mortem confirmation of fetal brain abnormalities: challenges highlighted by the MERIDIAN cohort study.

OBJECTIVES: To assess and analyse the concordance between post-mortem findings and in utero magnetic resonance imaging (iuMRI) in the MERIDIAN (MRI to enhance the diagnosis of fetal developmental brain abnormalities in utero) cohort. DESIGN: Prospective cohort study. SETTING: Fetal medicine units in the UK. POPULATION: Pregnant women with a diagnosis of fetal brain abnormality identified on ultrasound at 18 weeks of gestation or later. METHODS: All pregnancies from the MERIDIAN study that resulted in a abortion were included and the rate of uptake and success of post-mortem examinations were calculated. In the cases in which diagnostic information about the fetal brain was obtained by post-mortem, the results were compared with the diagnoses from iuMRI. MAIN OUTCOME MEASURE: Outcome reference diagnosis from post-mortem examination. RESULTS: A total of 155 from 823 pregnancies (19%) ended in a termination of pregnancy and 71 (46%) had post-mortem brain examinations, 62 of which were diagnostically adequate. Hence, the overall rate of successful post-mortem investigation was 40%, and for those cases there was a concordance rate of 84% between iuMRI and post-mortem examination. Detailed information is provided when the results of the post-mortem examination and the iuMRI study differed. CONCLUSIONS: We have shown tissue-validation of radiological diagnosis is hampered by a low rate of post-mortem studies in fetuses aborted with brain abnormalities, a situation further compounded by a 12% rate of autopsy being technically unsuccessful. The agreement between iuMRI and post-mortem findings is high, but our analysis of the discrepant cases provides valuable clues for improving how we provide information for parents. TWEETABLE ABSTRACT: iuMRI should be considered a reliable indicator of fetal brain abnormalities when post-mortem is not performed.

The financial burden associated with multiple shoulder dislocations and the potential cost savings of surgical stabilization.

INTRODUCTION: Shoulder dislocation is a costly problem and can have a high risk for recurrent instability after initial dislocation based on well-defined patient characteristics. Patients with recurrent instability can be treated with shoulder stabilizing procedures. Although more costly, surgery may decrease the overall health care burden of managing a patient with multiple shoulder dislocations nonoperatively. METHODS: We performed a retrospective chart review of all patients who presented to the emergency department (ED) with a diagnosis of a shoulder dislocation at a level 1 academic trauma center during the year 2016. Patient information regarding the current dislocation episode, previous dislocations, shoulder surgeries, and postreduction follow-up was gathered. These data were then used to determine the average cost of an ED presentation for a shoulder dislocation episode as obtained from the hospital finance department. The average cost of shoulder stabilization surgery was used to conduct a cost-benefit analysis of operative vs. nonoperative management. RESULTS: Data were collected on 104 individuals who presented to the ED with shoulder dislocations. Of these, 65 were primary dislocations and 39 were recurrent dislocations. Twelve patients underwent shoulder stabilization surgery after their ED presentation. The average cost to the institution for an ED visit requiring the closed reduction of a shoulder dislocation was $2207 ($973.21 without sedation and $3744 with conscious sedation). The average cost of a shoulder stabilization procedure performed at this same institution was $7807. DISCUSSION AND CONCLUSION: Although shoulder stabilization has a higher cost on the front end, this intervention results in cost savings if it prevents 2-3 future shoulder dislocations resulting in ED visits. These findings suggest that, for patients with a high risk for recurrent instability, not only would stabilization surgery help prevent subsequent dislocation events but would also minimize health care costs.

Synovial Cell Count Poorly Predicts Septic Arthritis in the Presence of Crystalline Arthropathy.

Introduction: A synovial cell count greater than 50,000/mm3 is the threshold most commonly used to diagnose septic arthritis. This lab value may be nonspecific in the setting of crystalline arthropathy. The purpose of this study was to evaluate the accuracy of diagnosing septic arthritis using a synovial cell count cut-off of 50,000/mm3 in the setting of crystalline arthropathy. Methods: This was a retrospective review of joint aspirations performed between July 1st, 2013 and June 30th, 2016. Synovial fluid samples were evaluated for cell count, crystals, Gram stain, and culture. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the synovial markers were calculated. Results: During the study period, 738 joint aspirations were sent for testing, of which 358 aspirations in 348 patients met inclusion criteria. There were 49 (13.7%) cases of culture-positive septic arthritis, and 47 patients underwent surgical irrigation and debridement. Gout and pseudogout crystals were present in 163 aspirates (45.5%). Three joints (0.8% overall rate) had concomitant crystalline arthropathy and septic arthritis, each of which had a synovial WBC ≥85,000/mm3. Increasing the WBC count cutoff to 85,000/mm3 demonstrated a specificity of 100%, but a PPV of 12.0%. Conclusions: A cut-off of 85,000/mm3 may be more appropriate to diagnose concomitant septic arthritis and crystalline arthropathy. We recommend medical management and observation in patients with crystal-positive joint aspirations unless the synovial cell count is elevated above 85,000/mm3. Prospective studies using this treatment guideline are needed to evaluate its validity and accuracy.

Erratum: Epigenome-wide association of father's smoking with offspring DNA methylation: a hypothesis-generating study.

[This corrects the article DOI: 10.1093/eep/dvz023.][This corrects the article DOI: 10.1093/eep/dvz023.].

Tuning dimensionality in van-der-Waals antiferromagnetic Mott insulators TMPS3.

We present an overview of our recent work in tuning and controlling the structural, magnetic and electronic dimensionality of 2D van-der-Waals antiferromagnetic compounds (Transition-Metal)PS3. Low-dimensional magnetic systems such as these provide rich opportunities for studying new physics and the evolution of established behaviours with changing dimensionality. These materials can be exfoliated to monolayer thickness and easily stacked and combined into functional heterostructures. Alternatively, the application of hydrostatic pressure can be used to controllably close the van-der-Waals interplanar gap and tune the crystal structure and electron exchange paths towards a 3D nature. We collect and discuss trends and contrasts in our data from electrical transport, Raman scattering and synchrotron x-ray measurements, as well as insight from theoretical calculations and other results from the literature. We discuss structural transitions with pressure common to all materials measured, and link these to Mott insulator-transitions in these compounds at high pressures. Key new results include magnetotransport and resistivity data in the high-pressure metallic states, which show potentially interesting qualities for a new direction of future work focussed on low temperature transport and quantum critical physics.

Analysis of 270 fetuses with non-visualization of cavum septi pellucidi and vergae on in-utero magnetic resonance imaging.

OBJECTIVE: To analyze a large retrospective cohort of fetuses in which the cavum septi pellucidi and vergae (CSPV) was not present or was not in its expected position on in-utero magnetic resonance imaging (iuMRI), in order to describe the possible causes of that finding and provide a diagnostic approach to assess such cases in clinical practice using iuMRI. METHODS: This was a retrospective study of fetuses that underwent iuMRI at a single institution, over an 18-year period (2000-2017 inclusive), in which the CSPV was not visualized or was abnormal. All iuMRI studies were reviewed and classified as CSPV being not present, disrupted (visualization of remnants of an otherwise normally placed CSPV) or malpositioned (CSPV was present, but not in its expected position). We describe the neuropathology present in each of the groups. RESULTS: Of the 270 fetuses that met the inclusion criteria, the CSPV was described as malpositioned in 150 (56%), disrupted in 71 (26%) and not present in 49 (18%). Malpositioned CSPV was present only in cases with agenesis of the corpus callosum and three specific patterns of malpositioning are described, depending on the location of the leaflets of the CSPV and fornix. Disrupted CSPV was present in fetuses with hydrocephalus or pathologies causing extensive brain parenchymal injury. Not present CSPV was found in cases with holoprosencephaly or when absence of the CSPV appeared to be an isolated finding. CONCLUSION: We have described a large cohort of fetuses with non-visualization of a normal CSPV on iuMRI and present a categorical classification system based on the CSPV being not present, disrupted or malpositioned. This approach should help in the diagnosis of the underlying cause of a CSPV abnormality. © 2019 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Epigenome-wide association of father's smoking with offspring DNA methylation: a hypothesis-generating study.

Epidemiological studies suggest that father's smoking might influence their future children's health, but few studies have addressed whether paternal line effects might be related to altered DNA methylation patterns in the offspring. To investigate a potential association between fathers' smoking exposures and offspring DNA methylation using epigenome-wide association studies. We used data from 195 males and females (11-54 years) participating in two population-based cohorts. DNA methylation was quantified in whole blood using Illumina Infinium MethylationEPIC Beadchip. Comb-p was used to analyse differentially methylated regions (DMRs). Robust multivariate linear models, adjusted for personal/maternal smoking and cell-type proportion, were used to analyse offspring differentially associated probes (DMPs) related to paternal smoking. In sensitivity analyses, we adjusted for socio-economic position and clustering by family. Adjustment for inflation was based on estimation of the empirical null distribution in BACON. Enrichment and pathway analyses were performed on genes annotated to cytosine-phosphate-guanine (CpG) sites using the gometh function in missMethyl. We identified six significant DMRs (Sidak-corrected P values: 0.0006-0.0173), associated with paternal smoking, annotated to genes involved in innate and adaptive immunity, fatty acid synthesis, development and function of neuronal systems and cellular processes. DMP analysis identified 33 CpGs [false discovery rate (FDR) < 0.05]. Following adjustment for genomic control (λ = 1.462), no DMPs remained epigenome-wide significant (FDR < 0.05). This hypothesis-generating study found that fathers' smoking was associated with differential methylation in their adolescent and adult offspring. Future studies are needed to explore the intriguing hypothesis that fathers' exposures might persistently modify their future offspring's epigenome.

Editorial Commentary: Stump Sparing or Footprint Exposing? Management of the Tibial Remnant During Posterior Cruciate Ligament Reconstruction.

Surgical management of an isolated grade III posterior cruciate ligament tear has been enveloped in debate since the first reconstruction technique report was written by Hey Groves in 1919. With the evolution of arthroscopy, party lines have been drawn over tibial inlay versus transtibial techniques, as well as single- versus double-bundle techniques. More subtle controversy exists regarding autograft versus allograft, outside-in versus inside-out drilling, and treatment of the tibial footprint of the posterior cruciate ligament. New remnant-sparing techniques, using a trans-septal posterior portal, may augment biology, maintain better proprioception, and mitigate abrasive wear at the "killer turn." However, longer-term comparative studies will be necessary to determine the existence of any clinically significant improvement in outcome.

Is Acromioplasty Ever Indicated During Rotator Cuff Repair?

Based on data from a national healthcare insurance carrier in the United States between 2010 and 2012, orthopedic surgeons performed an acromioplasty procedure on 73 to 76% of their arthroscopic rotator cuff repairs. This has remained a prevalent arthroscopic adjunct despite the controversies disputing the role and etiology of external impingement on symptomatic rotator cuff disease. Within the past decade, several randomized studies have demonstrated negligible benefits with acromioplasty performed alongside rotator cuff repair, with no significant differences in either patient-reported outcome scores or retear rates). Conversely, other authors have suggested higher rates of reoperation with rotator cuff repair alone. Critical shoulder angle, an objective measure of lateral acromion extension and glenoid inclination that is considered a gauge of external impingement, has demonstrated an association with rotator cuff tears; Despite this, patient-reported outcomes do not consistently correlate with critical shoulder angle or other variants in acromial morphology after arthroscopic full-thickness rotator cuff repair. Evidenced-based data is currently lacking to support routine use of acromioplasty in all cases of rotator cuff repair. However, the current available studies do present design flaws, namely statistical underpowering, particularly in type III acromion morphology; inadequate short-term follow-up; lack of imaging data to assess cuff healing; and insensitive outcome measures to capture the theorized benefits of subacromial decompression. Additionally, several relevant merits of acromioplasty have been reported, including decreased abrasive wear with prominent type III acromial morphology, release of natural growth factors to improve rotator cuff healing, and improved visualization during rotator cuff repair. Further evaluation is needed to determine the correct indications for acromioplasty in the setting of cuff repair. Current data would indicate that acromioplasty can be used safely at the discretion of the operating surgeon based on preoperative and intraoperative findings.

The rate of brain abnormalities on in utero MRI studies in fetuses with normal ultrasound examinations of the brain and calculation of indicators of diagnostic performance.

AIM: To estimate the rate of unexpected brain abnormalities detected by in utero magnetic resonance imaging (iuMRI) in fetuses without abnormalities at ultrasonography (USS). MATERIALS AND METHODS: A prospective cohort study of pregnant women whose fetus had no structural brain (or body) abnormalities recognised on antenatal ultrasonography. Women were recruited from 12 centres across the UK and underwent iuMRI at 18 gestational weeks or more in the [blinded for review]. The imaging studies were reviewed by an experienced neuroradiologist. The positive and negative predictive values of both USS and iuMRI have been calculated by combining the results of this study with the results from the main [blinded for review] study. RESULTS: One hundred and ninety-eight pregnant women were recruited and underwent iuMRI of 205 fetuses. Brain abnormalities were shown on iuMRI in two fetuses that were not recognised on USS (one case of a focal cortical abnormality and one case of mild ventriculomegaly). The negative predictive value for USS was 99.5% and 100% for iuMRI. CONCLUSIONS: To the authors' knowledge, this is the first study comparing USS and iuMRI in low-risk pregnancies. USS has a comparatively high rule-out for fetal brain abnormalities and should remain the screening tool of choice.

Dielectric Response of Quantum Critical Ferroelectric as a Function of Pressure.

In this work we report for the first time measurements of the dielectric loss of single-crystal SrTiO3 under the application of hydrostatic pressure up to 20 kbar and temperatures down to 200 mK which allow us to comment on the evolution of new fundamental material properties and their relationship with the recently discovered quantum critical phenomena in this material. The well known 18 K peak or shoulder was no longer observed after pressure was applied, even after subsequently removing it, suggesting it is associated with the twin walls formed at the 110 K cubic-tetragonal transition. The family of familiar peaks were all seen to increase in temperature linearly with pressure and the height of the 9.4 K peak was drastically suppressed by even the smallest pressures. This peak is discussed in the context of a postulated ferroelectric quantum critical point in SrTiO3 and the behaviour of its size linked to the position of this point on the recently established phase diagram.

Stabilization of molten salt materials using metal chlorides for solar thermal storage.

The effect of a variety of metal-chlorides additions on the melting behavior and thermal stability of commercially available salts was investigated. Ternary salts comprised of KNO3, NaNO2, and NaNO3 were produced with additions of a variety of chlorides (KCl, LiCl, CaCl2, ZnCl2, NaCl and MgCl2). Thermogravimetric analysis and weight loss experiments showed that the quaternary salt containing a 5 wt% addition of LiCl and KCl led to an increase in short term thermal stability compared to the ternary control salts. These additions allowed the salts to remain stable up to a temperature of 630 °C. Long term weight loss experiments showed an upper stability increase of 50 °C. A 5 wt% LiCl addition resulted in a weight loss of only 25% after 30 hours in comparison to a 61% loss for control ternary salts. Calorimetry showed that LiCl additions allow partial melting at 80 °C, in comparison to the 142 °C of ternary salts. This drop in melting point, combined with increased stability, provided a molten working range increase of almost 100 °C in total, in comparison to the control ternary salts. XRD analysis showed the oxidation effect of decomposing salts and the additional phase created with LiCl additions to allow melting point changes to occur.

Microbial characteristics in homes of asthmatic and non-asthmatic adults in the ECRHS cohort.

Microbial exposures in homes of asthmatic adults have been rarely investigated; specificities and implications for respiratory health are not well understood. The objectives of this study were to investigate associations of microbial levels with asthma status, asthma symptoms, bronchial hyperresponsiveness (BHR), and atopy. Mattress dust samples of 199 asthmatics and 198 control subjects from 7 European countries participating in the European Community Respiratory Health Survey II study were analyzed for fungal and bacterial cell wall components and individual taxa. We observed trends for protective associations of higher levels of mostly bacterial markers. Increased levels of muramic acid, a cell wall component predominant in Gram-positive bacteria, tended to be inversely associated with asthma (OR's for different quartiles: II 0.71 [0.39-1.30], III 0.44 [0.23-0.82], and IV 0.60 [0.31-1.18] P for trend .07) and with asthma score (P for trend .06) and with atopy (P for trend .02). These associations were more pronounced in northern Europe. This study among adults across Europe supports a potential protective effect of Gram-positive bacteria in mattress dust and points out that this may be more pronounced in areas where microbial exposure levels are generally lower.

Should we perform in utero MRI on a fetus at increased risk of a brain abnormality if ultrasonography is normal or shows non-specific findings?

There are a number of reasons why a pregnant woman might be considered to have an increased risk of carrying a fetus with a brain abnormality, but they fall broadly into two groups. First, there may be a relevant family history usually, but not always, when a fetus/child from a previous pregnancy has a developmental brain abnormality and a clinical geneticist judges that there is a risk of recurrence. Second, there may be findings in their current pregnancy that increases the risk of the fetus either having a developmental brain abnormality or accruing acquired brain pathology. Antenatal ultrasonography remains the mainstay of fetal screening and anomaly scanning, but there is now persuasive evidence that in utero magnetic resonance imaging should have an important supporting role. This is important, as more accurate and more certain diagnoses are central to providing parents with accurate information about the likely clinical outcome. In pregnancies at increased risk of brain abnormalities, it is also important to provide the best quality information that the fetal brain is normal to provide reassurance to parents. In this paper, we review the proposition that in utero magnetic resonance imaging should be used in pregnancies at increased risk of brain abnormalities, even if the consultant-led ultrasound examination is normal or showed non-specific findings only.

Single-molecule sequencing and Hi-C-based proximity-guided assembly of amaranth (Amaranthus hypochondriacus) chromosomes provide insights into genome evolution.

BACKGROUND: Amaranth (Amaranthus hypochondriacus) was a food staple among the ancient civilizations of Central and South America that has recently received increased attention due to the high nutritional value of the seeds, with the potential to help alleviate malnutrition and food security concerns, particularly in arid and semiarid regions of the developing world. Here, we present a reference-quality assembly of the amaranth genome which will assist the agronomic development of the species. RESULTS: Utilizing single-molecule, real-time sequencing (Pacific Biosciences) and chromatin interaction mapping (Hi-C) to close assembly gaps and scaffold contigs, respectively, we improved our previously reported Illumina-based assembly to produce a chromosome-scale assembly with a scaffold N50 of 24.4 Mb. The 16 largest scaffolds contain 98% of the assembly and likely represent the haploid chromosomes (n = 16). To demonstrate the accuracy and utility of this approach, we produced physical and genetic maps and identified candidate genes for the betalain pigmentation pathway. The chromosome-scale assembly facilitated a genome-wide syntenic comparison of amaranth with other Amaranthaceae species, revealing chromosome loss and fusion events in amaranth that explain the reduction from the ancestral haploid chromosome number (n = 18) for a tetraploid member of the Amaranthaceae. CONCLUSIONS: The assembly method reported here minimizes cost by relying primarily on short-read technology and is one of the first reported uses of in vivo Hi-C for assembly of a plant genome. Our analyses implicate chromosome loss and fusion as major evolutionary events in the 2n = 32 amaranths and clearly establish the homoeologous relationship among most of the subgenome chromosomes, which will facilitate future investigations of intragenomic changes that occurred post polyploidization.