Total Ankle Arthroplasty Templating: Preoperative Computer Templating Correlates Highly with Intraoperative Component Selection.

Proper alignment and sizing are critical to the performance of a successful total ankle arthroplasty. While it is common practice in preoperative planning prior to total knee and total hip arthroplasty, preoperative computer templating has not been well established in the setting of total ankle arthroplasty. A retrospective review of all total ankle arthroplasties performed during a 10-year period by a single fellowship-trained orthopaedic surgeon was conducted. Computer templating was utilized for all preoperative AP and lateral standing radiographs, and templated component sizes were compared to the operative reports and postoperative radiographs to determine the precision of the available templates. Statistical analysis was performed with Interclass Correlation Coefficients (ICC) and descriptive statistical tests. Seventy patients with a mean age of 64.8 years (range, 48-87) and mean BMI of 30.34 (range, 19.1-55.6) were included. The Interclass Correlation Coefficient demonstrated that both the AP (ICC 0.80 - 95% CI 0.679-0.876) and lateral (ICC 0.786 - 95% CI 0.655-0.867) radiographs provided for accurate tibial total ankle arthroplasty component templating. Similarly, the AP (ICC 0.842 - 95% CI 0.745-0.902) and lateral (ICC 0.809 - 95% CI 0.692-0.881) radiographs provided for accurate talar templating. No differences were observed when comparing AP to lateral radiographs in percentage of correct component templating: tibial AP 61.4% vs lateral 58.6%, p=0.119 and talar component anterior-posterior 57.1% vs lateral 45.7%, p=0.176. These study findings demonstrate that preoperative templating for total ankle arthroplasties is accurate in determining appropriate implant sizing. Accurate templating is an absolute necessity for future templating studies. Level of clinical evidence: III.

Quantum-cascade-laser-absorption-spectroscopy diagnostic for temperature, pressure, and NO X 2 Π 1/2 at 500 kHz in shock-heated air at elevated pressures.

The design, validation, and application of a quantum-cascade-laser-absorption-spectroscopy diagnostic for measuring gas temperature, pressure, and nitric oxide (NO) in high-temperature air are presented. A distributed-feedback quantum-cascade laser (QCL) centered near 1976c m -1 was used to scan across two transitions of NO in its ground electronic state (X 2 Π 1/2). A measurement rate of 500 kHz was achieved using a single QCL by: (1) performing current modulation through a bias-tee, and (2) targeting closely spaced transitions with a large difference in lower-state energy. The diagnostic was validated in a mixture of 95% argon and 5% NO, which was shock-heated to ≈2000 to 3700 K. The average mean percent differences between laser-absorption-spectroscopy (LAS) measurements and predictions from shock-jump relations for temperature, pressure, and NO mole fraction were 3.1%, 4.1%, and 6.5%, respectively. The diagnostic was then applied to characterize shock-heated air at high temperatures (up to ≈5500K) and high pressures (up to 12 atm) behind either incident or reflected shocks. The LAS measurements were compared to theoretical predictions from shock-jump relations, pressure sensors mounted in the wall of the shock tube, and equilibrium values of the NO mole fraction. The average mean percent differences between LAS measurements and their aforementioned reference values were 3.2%, 10.8%, and 10.4% for temperature, pressure, and NO mole fraction, respectively. Last, a comparison between a measured NO mole fraction time history and a time-stepped homogeneous reactor simulation performed using two different chemical kinetics mechanisms is presented.

Pulse-burst spontaneous Raman thermometry of unsteady wave phenomena in a shock tube.

A high-speed temperature diagnostic based on spontaneous Raman scattering (SRS) was demonstrated using a pulse-burst laser. The technique was first benchmarked in near-adiabatic ${{\rm H}_2} \text{-} {\rm air}$ flames at a data-acquisition rate of 5 kHz using an integrated pulse energy of 1.0 J per realization. Both the measurement precision and accuracy in the flame were within 3% of adiabatic predictions. This technique was then evaluated in a challenging free-piston shock tube environment operated at a shock Mach number of 3.5. SRS thermometry resolved the temperature in post-incident and post-reflected shock flows at a repetition rate of 3 kHz and clearly showed cooling associated with driver expansion waves. Collectively, this Letter represents a major advancement for SRS in impulsive facilities, which had previously been limited to steady state regions or single-shot acquisition.

Bone Mineral Density and Sports Participation.

The objective of our study was to identify differences in bone mineral density (BMD) according to different sports among adolescents, as well as to identify assessments of relevant mediators. The sample consisted of 429 adolescents with a mean age of 13.3 ± 1.7 yr. The sports modalities that we evaluated were judo, karate, kung fu, swimming, basketball, and soccer. Nonsports group was composed of 111 adolescents. Bone density was assessed using dual-energy X-ray absorptiometry. Regarding BMD values, female engaged in karate had higher BMD values than girls from the no sports group (p = 0.01). Boys engaged in soccer and karate presented the highest BMD values than all the other groups (p = 0.01). The most relevant mediators were the body mass index and lean soft tissue for boys and girls. Different sports presented different results regarding BMD gains, which were influenced by body mass index and whole-body lean soft tissue.

Coronal Remodeling Potential of Pediatric Distal Radius Fractures.

BACKGROUND: Distal radius fractures in the pediatric population are common injuries with a remarkable capability to remodel. The degree of angulation that can reasonably be expected to remodel is controversial though, particularly when it comes to angulation in the coronal plane. The purpose of this study was to quantify the rate of coronal remodeling, via the distal radius physis, present in a retrospective cohort of skeletally immature patients with coronally angulated distal radius fractures. METHODS: A retrospective chart review was performed to identify skeletally immature patients treated for an angulated distal radius fracture with over 10 degrees of angulation in the coronal plane during the healing process at a single institution by either a pediatric orthopaedic surgeon or an orthopaedic trauma surgeon from 2009 to 2018. Coronal angulation was measured at every visit where radiographs were available from time of injury to the final follow-up visit to determine the rate of remodeling. RESULTS: In total, 36 patients with distal radius fractures with a mean age of 7.93 years (range, 4 to 12 y) at the time of injury were identified. The median peak angulation during the healing process in the coronal plane was 17 degrees (range, 12.4 to 30.4 degrees). The mean follow-up period was 6.4 months from the time of maximum angulation to the final visit. The median time from cast removal to final follow-up was 6.59 months (range, 2.5 to 8.72 mo). At final follow-up, the median coronal angulation was 3.35 degrees (range, 0.24 to 14.0 degrees). At the 95% confidence level, remodeling rates ranged from 2.00 to 2.59 degrees per month. The mean rate of coronal angulation remodeling from maximum angulation to final follow-up was 2.30 degrees per month. CONCLUSIONS: Distal radius fractures have a large capacity to remodel in the pediatric population. This remodeling occurs in a predictable and reliable manner, even in the coronal plane. On the basis of this study, coronal angulation was shown to remodel at a rate of at least 2 degrees per month for the first 6 months following the injury, which should likely continue at a similar rate for the first year after the injury. Repeat manipulation is not indicated in skeletally immature patients where the maximum coronal angulation is <24 degrees, which provides a conservative estimate of the amount of remodeling that can be expected to occur in the first year after fracture. LEVEL OF EVIDENCE: Level III-retrospective comparative study.

Sports Participation Decreases the Incidence of Traumatic, Nonsports-Related Fractures Among Adolescents.

OBJECTIVES: To investigate the effects of different sports on the incidence of traumatic fractures (TF; sport-related fractures and those occurring in daily activities) among adolescents during the 9-month follow-up period. METHODS: The adolescents were contacted in 11 different locations (3 public/private schools and 8 sports clubs), and the final sample was divided into 3 groups: control (n = 121), swimming (n = 51), and impact sports (n = 142). The incidence of TF was calculated by considering the exposure to sports (TF/1000 h). RESULTS: In the overall sample, the incidence of TF was 1.29 TF/1000 hours of sports exposure, while the incidence of sport-related TF was 0.39 TF/1000 hours of sports exposure. Adolescents engaged in sports (P = .004), independently of type (P = .001), for 3 or more days per week (P = .004) and more than 60 minutes per day (P = .001) had lower incidence of TF. Adolescents engaged in more than 300 minutes per week of sport (0.17 TF/1000 h) had lower incidence than those who did not (2.06 TF/1000 h [P = .001]). A similar finding was observed for sport-related TF (≥300 min/wk: 0.08 TF/1000 h vs 300 min/wk: 0.615 TF/1000 h [P = .02]). CONCLUSION: Adolescents engaged in sports showed a lower incidence of TF than nonengaged adolescents.

Backscatter particle image velocimetry via optical time-of-flight sectioning.

Conventional particle image velocimetry (PIV) configurations require a minimum of two optical access ports, inherently restricting the technique to a limited class of flows. Here, the development and application of a novel method of backscattered time-gated PIV requiring a single-optical-access port is described along with preliminary results. The light backscattered from a seeded flow is imaged over a narrow optical depth selected by an optical Kerr effect (OKE) time gate. The picosecond duration of the OKE time gate essentially replicates the width of the laser sheet of conventional PIV by limiting detected photons to a narrow time-of-flight within the flow. Thus, scattering noise from outside the measurement volume is eliminated. This PIV via the optical time-of-flight sectioning technique can be useful in systems with limited optical access and in flows near walls or other scattering surfaces.

Tunable Electroosmosis-Based Femto-Liter Pipette: A Promising Tool toward Living-Cell Surgery.

Single-cell analysis has attracted increasing attention because of cell heterogeneities. Various strategies have been developed for analyzing single cells, but most of these analytical processes kill the cells. Tools that can qualitatively and quantitatively measure the cellular contents without killing the cell are highly demanding because they enable us to conduct single-cell time-course studies (e.g., to examine how a cell responds to a therapy before, during, and after a treatment). Here we develop a femto-liter (fL) pipet to serve this purpose. To ensure that we can accurately and precisely pipet fL solutions, we fill all conduits with liquid and use an electroosmotic pump (EOP) as the driving force to facilitate withdrawal of cellular contents from single cells. We tentatively term this device an EOP-driven pipette or EDP. We characterize the EDP for accurately and precisely withdrawing solution from ∼250 fL to 80 nL; a volume range that covers the applications for most types of cells. To demonstrate the feasibility of utilizing the EDP for a single-cell time-course study, we utilize the EDP to take the cellular contents out at different times during the course of a zebrafish embryo development for cholesterol measurements. More than 50% of the embryos survive after each pipetting and analysis step, and this number will increase considerably as we improve our cell manipulation skills and reduce the pipet-tip diameter. We expect this EDP to become an effective tool for single-cell time-course studies.

High-performance liquid chromatographic cartridge with gradient elution capability coupled with UV absorbance detector and mass spectrometer for peptide and protein analysis.

We discuss the construction and performance of a high-performance liquid chromatography cartridge that we developed that resulted from a culmination of previous research. We have recently developed an innovative approach to creating gradient elutions using dual electroosmotic pumps and a series of three valves. This method has been proved to be the most reproducible and robust in producing gradients compared to our previously tested methods. Using this approach, we have assembled a high-performance liquid chromatography cartridge powered and controlled via a computer. We have successfully coupled the cartridge with an ultraviolet absorbance detector and a mass spectrometer for separating complex protein/peptide samples. The cartridge is readily coupled with other detectors such as electrochemical detector and laser-induced fluorescence detector.

Impact of Martial Arts (Judo, Karate, and Kung Fu) on Bone Mineral Density Gains in Adolescents of Both Genders: 9-Month Follow-Up.

PURPOSE: To compare bone mineral density (BMD) gains in adolescents of both genders stratified according to different martial art styles in a 9-month follow-up study. METHODS: The longitudinal study consisted of 29 adolescents of both genders and age between 11 and 17 years stratified into a control group (not engaged in any sport) and 50 fighters (kung fu/karate, n = 29; judo, n = 21). All 79 subjects underwent anthropometric measures (weight, height, leg length, and height set) and dual-energy X-ray absorptiometry (BMD, in g/cm2) at 2 moments, baseline and 9 months later. Maturity offset (age at peak height velocity), lean soft tissue, chronological age, and resistance training were treated as covariates. RESULTS: Male judoists presented higher gains in BMD-spine [0.098 g/cm2 (95% confidence interval, 0.068-0.128)] than control group [0.040 g/cm2 (95% confidence interval, 0.011-0.069)] (post hoc test with P = .030). There was no effect of martial art on BMD gains among girls. Independently of gender, in all multivariate models, lean soft tissue constituted the most relevant covariate. CONCLUSIONS: Judo practice in adolescents affected the bone accrual significantly after 9-month follow-up compared with controls, mainly in boys.

The Impact of Training Load on Bone Mineral Density of Adolescent Swimmers: A Structural Equation Modeling Approach.

PURPOSE: To investigate the mediating effect of muscle mass on the relationship between training load and bone density in adolescent swimmers. METHODS: A cross-sectional study involving 87 control and 22 swimmers aged 10-19 years (overall sample: n = 109). Swimmers had a minimum of 1 year of competition in regional and national championships, and control adolescents reported 1 year without any organized sport. Bone density was the main outcome (dual-energy X-ray absorptiometry), which was measured in upper limbs, lower limbs, spine, and whole body. Monthly training load was the independent variable, while the mediation effect of lean soft tissue was assessed. Maturity offset, age, inflammation, and vitamin D intake were treated as covariates. RESULTS: Swimmers had lower bone density than controls; there was a significant and positive relationship between training load and muscle mass. In boys, training load presented a negative correlation with bone density in lower limbs [r = -.293; 95% confidence interval (CI), -.553 to -.034]. In girls, training load was negatively related to bone mineral density in lower limbs (r = .563; 95% CI, -.770 to -.356) and whole body (r = -.409; 95% CI, -.609 to -.209). CONCLUSION: Training load had a negative relationship on bone density of swimmers of both sexes, independently of the positive effect of lean soft tissue on bone density.

Impact sports and bone fractures among adolescents.

The objective of the present study was to investigate the effects of different sports on stress fractures among adolescents during a 9-month follow-up period. The sample was composed of 184 adolescents divided into three groups (impact sports [n = 102]; swimming [n = 35]; non-sports [n = 47]). The occurrence of stress fracture was reported by participants and coaches. As potential confounders we considered age, sex, resistance training, body composition variables and age at peak of height velocity. There were 13 adolescents who reported fractures during the 9-month period. Bone mineral density values were higher in adolescents engaged in impact sports (P-value = 0.002). Independently of confounders, the risk of stress fracture was lower in adolescents engaged in impact sports than in non-active adolescents (hazard ratio [HR] = 0.23 [95% confidence interval (CI) = 0.05 to 0.98]), while swimming practice was not associated to lower risk of fracture (HR = 0.49 [95% CI = 0.09 to 2.55]). In conclusion, the findings from this study indicate the importance of sports participation among adolescents in the reduction of stress fracture risk, especially with impact sports. More importantly, these results could be relevant for recognising adolescents in danger of not reaching their potential for peak bone mass and later an increased risk of fractures.

Basketball Affects Bone Mineral Density Accrual in Boys More Than Swimming and Other Impact Sports: 9-mo Follow-Up.

The objective of this study was to analyze the effect of different sports on bone mineral density (BMD) accrual among male adolescents during a 9-mo follow-up. The sample was composed of 82 boys (control [n = 13], basketball [n = 14], karate [n = 9], soccer [n = 18], judo [n = 12], and swimming [n = 16]) who were followed up for 9 mo (from October 2013 to August 2014). BMD (gram per square centimeter) was assessed at baseline and follow-up using a dual-energy X-ray absorptiometry scanner, whereas somatic maturation was estimated through the use of the peak height velocity. Vitamin D consumption was assessed by questionnaire. After 9 mo of follow-up, all groups (including the control group) presented significant BMD accrual (overall sample: 4.5% in the whole body). On the other hand, the basketball group presented higher BMD accrual in the upper limbs (17.6%) than the control group (7.2%). A similar difference was observed in whole-body BMD (control group: 4.1% vs basketball group: 7.1%). The basketball group had significantly higher BMD gains than the control group and other sports groups.

Batrachochytrium dendrobatidis exposure effects on foraging efficiencies and body size in anuran tadpoles.

Chytridiomycosis, the amphibian disease caused by the pathogenic fungus Batrachochytrium dendrobatidis (Bd), is fatal to adults of many species. Bd is largely sublethal to amphibian larvae; however, it is known to reduce larval (i.e. tadpole) growth rates, with possible long-term effects on population dynamics and fitness. We conducted an experiment to test how Bd altered southern leopard frog Lithobates sphenocephalus tadpole mouthpart damage, percentage of food ingested, and subsequent body size. We examined our results using path analyses. We hypothesized that Bd would increase mouthpart damage, causing less food to be ingested, and ultimately reduce body size. In our model, both Bd exposure and increased mouthpart damage significantly reduced food ingested and subsequent body size. However, our study provides evidence against the long-standing hypothesis of mouthpart damage as a pathway for Bd-induced reductions in larval group. Here we provide evidence for reduced foraging efficiency (percentage of food ingested) as a mechanism for Bd-induced reductions in body size. This work highlights the importance of studying the sublethal effects of Bd on larval amphibians.

High-pressure open-channel on-chip electroosmotic pump for nanoflow high performance liquid chromatography.

Here, we construct an open-channel on-chip electroosmotic pump capable of generating pressures up to ∼170 bar and flow rates up to ∼500 nL/min, adequate for high performance liquid chromatographic (HPLC) separations. A great feature of this pump is that a number of its basic pump units can be connected in series to enhance its pumping power; the output pressure is directly proportional to the number of pump units connected. This additive nature is excellent and useful, and no other pumps can work in this fashion. We demonstrate the feasibility of using this pump to perform nanoflow HPLC separations; tryptic digests of bovine serum albumin (BSA), transferrin factor (TF), and human immunoglobulins (IgG) are utilized as exemplary samples. We also compare the performance of our electroosmotic (EO)-driven HPLC with Agilent 1200 HPLC; comparable efficiencies, resolutions, and peak capacities are obtained. Since the pump is based on electroosmosis, it has no moving parts. The common material and process also allow this pump to be integrated with other microfabricated functional components. Development of this high-pressure on-chip pump will have a profound impact on the advancement of lab-on-a-chip devices.

Optimal digestion theory does not predict the effect of pathogens on intestinal plasticity.

One prediction of optimal digestion theory is that organisms will increase the relative length of their digestive tracts when food resources become limited. We used theory of optimal digestion to test whether tadpoles can adjust the relative length of their intestines when challenged with the fungal pathogen Batrachochytrium dendrobatidis (Bd). The degree of tadpole mouthpart damage, a symptom of Bd infections that reduces food consumption, was associated positively with the length of tadpole intestines relative to their body size, consistent with optimal digestion theory. After controlling for mouthpart damage, tadpoles exposed to Bd had shorter intestines relative to their body size, opposite to the predictions of optimal digestion theory. One explanation of why tadpoles with higher Bd loads have shorter relative intestinal lengths is that they divert energy from maintaining intestinal and overall growth towards anti-parasite defences.

Mouthparts of southern leopard frog, Lithobates sphenocephalus, tadpoles not affected by exposure to a formulation of glyphosate.

This study evaluated the impacts of Roundup® on tadpole mouthpart damage as a mechanism for reduced growth and developmental rates in Lithobates sphenocephalus (Southern leopard frog) tadpoles. We did not find evidence that Roundup(®) damages larval mouthparts, nor was there a significant relationship between mouthpart damage and either body condition or developmental rate. However, the highest concentration of Roundup® significantly stunted development compared to all other treatments. Although we observed a significant effect of Roundup® on developmental rate, we conclude that mouthpart damage is likely not a mechanism for this life history response.

The C-terminal transactivation domain of MITF interacts promiscuously with co-activator CBP/p300.

The microphthalmia-associated transcription factor (MITF) is one of four closely related members of the MiT/TFE family (TFEB, TFE3, TFEC) that regulate a wide range of cellular processes. MITF is a key regulator of melanocyte-associated genes, and essential to proper development of the melanocyte cell lineage. Abnormal MITF activity can contribute to the onset of several diseases including melanoma, where MITF is an amplified oncogene. To enhance transcription, MITF recruits the co-activator CREB-binding protein (CBP) and its homolog p300 to gene promoters, however the molecular determinants of their interaction are not yet fully understood. Here, we characterize the interactions between the C-terminal MITF transactivation domain and CBP/p300. Using NMR spectroscopy, protein pulldown assays, and isothermal titration calorimetry we determine the C-terminal region of MITF is intrinsically disordered and binds with high-affinity to both TAZ1 and TAZ2 of CBP/p300. Mutagenesis studies revealed two conserved motifs within MITF that are necessary for TAZ2 binding and critical for MITF-dependent transcription of a reporter gene. Finally, we observe the transactivation potential of the MITF C-terminal region is reliant on the N-terminal transactivation domain for function. Taken together, our study helps elucidate the molecular details of how MITF interacts with CBP/p300 through multiple redundant interactions that lend insight into MITF function in melanocytes and melanoma.

Resource Use After Unwanted Sexual Experiences in Undergraduates: A Comprehensive Evaluation of Factors Related to the Decision to Seek Help.

The risk for sexual victimization in college is high, and although there can be significant mental and physical consequences for the survivor, resource utilization for this issue is extremely low. The current study used the frameworks of both the ecological model and the theory of planned behavior to examine factors related to resource use in undergraduate survivors of unwanted sexual experiences. The sample consisted of 217 undergraduates who reported at least one unwanted sexual experience while in college (89% female, 76.5% Caucasian, M age 19.6). Data were collected in an online survey from a private liberal arts college, and were analyzed using decision tree modeling. Results suggested that resource use was less related to demographic or event characteristics, but rather related to victim response to the event as well as perceptions about control over potential resource use. In addition to key assault prevention efforts, it is thus important to also support survivor mental health and self-efficacy postassault.

Minimally Invasive Medial Plate Osteosynthesis of High-Energy Pediatric Tibia Fractures.

OBJECTIVES: We report on the largest series to date of minimally invasive medial plate osteosynthesis of high-energy tibia fractures in skeletally immature patients. DESIGN: Retrospective. SETTING: Level 1 trauma center. PATIENTS: Skeletally immature patients with high-energy tibia fractures treated with minimally invasive medial plate osteosynthesis between 2006 and 2017. We identified 28 fractures in 26 patients. MAIN OUTCOME MEASURE: We reviewed the record for patient, injury, and treatment factors as well as for complications and reoperation. We assessed the relationships between age, implant selection, and implant removal using χ and t test analyses. RESULTS: Mean age was 12 years (4-15) with OTA/AO classifications including 42A (18), 42B (6), and 42C (4). There were 10 open fractures (1 type I, 2 type II, and 7 type III). Mean follow-up was 37.6 months (minimum 7). Mean time to full weight-bearing and union was 2 and 3 months, respectively. Plate stock (2.7, 3.5, and 4.5 mm) and length (6-20 holes) varied independent of age, P = 0.19. There were 2 superficial infections, one 15 mm leg length discrepancy, and one case of fasciotomy at the time of plate fixation for trauma-related compartment syndrome. Implant removal was more likely in younger patients (10.9 vs. 13.2 years, P = 0.04) and not associated with plate stock, P = 0.97. There were no neurovascular injuries, losses of reduction, or rotational deformities. Angulation was universally <5 degrees in the coronal plane and <10 degrees in the sagittal plane. CONCLUSIONS: Minimally invasive medial plate osteosynthesis of high-energy pediatric tibia fractures may be performed with a low rate of complications and should be considered in this select patient population with multiple injuries, high-energy mechanisms, and significant soft-tissue trauma. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.