Dynamics of a Laser-Induced Bubble above the Flat Top of a Solid Cylinder—Mushroom-Shaped Bubbles and the Fast Jet

The dynamics of a laser-induced bubble on top of a solid cylinder is studied both experimentally and numerically. When the bubble is generated close to the flat top along the axis of the cylinder and its maximum radius exceeds the one of the flat top surface, it collapses in the form of a mushroom with a footing on the cylinder, a long stem and a hat-like cap typical for a mushroom head. The head may collapse forming a thin, fast liquid jet into the stem, depending on bubble size and bubble distance to the top of the cylinder. Several experimental and numerical examples are given. The results represent a contribution to understand the behavior of bubbles collapsing close to structured surfaces and in particular, how thin, fast jets are generated.

Interventions to Educate Elementary Students on COVID-19

Students at MCG saw the potential to combine the community’s need for STEM-based programs in elementary schools with the growing need to distribute accurate information amidst the COVID-19 pandemic. In August 2020, MCG students initiated a year-long STEM project in partnership with a public elementary school. Through this program, pre-clinical medical students had the opportunity to teach relevant science related topics to fifth grade students. Particularly pertinent were subjects including COVID-19 basics, healthy lifestyle choices, chronic diseases, the human body, and infectious organisms.Answers were validated by evidence-based resources such as CDC, research journals, and NIH. The numerous benefits elementary school students received by participating in this program included early exposure to professionals in STEM, increased ability to formulate scientific questions, a safe and secure platform to be able to ask questions without feeling judged, and tools to form a positive association with healthcare professionals.A big component of a practicing family physician is teaching, and through this program, medical students were expected to grow their communication and leadership skills to become more effective teachers. With the added layer of the pandemic, it is vital that as future physicians we distribute information about the virus and safety precautions directly to our future generation of leaders, and allow for open and clear communication, explaining the science and presenting evidence based research on why certain precautions are mandatory.

Improving Snapdragon Cut Flower Production through High Tunnel Season Extension, Transplant Timing, and Cultivar Selection

The demand for locally grown, specialty cut flowers is increasing and now includes nontraditional regions for production, such as the U.S. Intermountain West. The objective of this study was to evaluate snapdragon (Antirrhinum majus L.) as a cool season, cut flower crop in northern Utah, where the high elevation and semiarid climate result in a short growing season with strong daily temperature fluctuations. High tunnel and field production methods were trialed in North Logan, UT (41.77°N, 111.81°W, 1382 m elevation) with cultivars ‘Chantilly’, ‘Potomac’, and ‘Rocket’ in 2018 and 2019. Each year, five to six transplant timings at 3-week intervals were tested, beginning in early February in high tunnels and ending in late May in an unprotected field. Stems were harvested and graded according to quality and stem length. High tunnels advanced production by 5 to 8 weeks, whereas field harvests continued beyond the high tunnel harvests by 2 to 8 weeks. High tunnels yielded 103 to 110 total stems per m2 (65% to 89% marketability), whereas field yields were 111 to 162 total stems per m2 (34% to 58% marketability). Overall, production was the greatest with March transplant timings in the high tunnels and mid-April transplant timings in the field. ‘Chantilly’ consistently bloomed the earliest on 4 and 6 May each year, ‘Potomac’ had the highest percentage of long stem lengths, and ‘Rocket’ extended marketable stem production through July in high tunnels. Selecting optimal transplant dates in the high tunnel and field based on cultivar bloom timing maximizes marketable yields and results in a harvest window lasting 4.5 months.

STUDYING THE INITIAL STABILITY OF A NEW TYPE OF HIP REPLACEMENT- SPIRON SHORT STEM

Objective: we perform this study with the following objective: Studying the initial stability of a new type of hip replacement-spiron short stem. Subjects and methods: Experiments to determine the deformability, elasticity and force capacity of the femur were used for the short stem and the long stem replacement corresponds to the original femur without the prosthesis. Along with that, we were evaluated short-term results of treatment for 70 patients with 92 Spiron hips replacement in the Institute of Trauma and Orthopedic-108 Military Central Hospital, from 2012 to 2016. Results: The analysis results showed that the Spiron short stem prosthetic had a significantly smaller displacement in the mid-frost bond than the Zweymuller long stem prosthesis. Clinical research: Harris’s score was 45.2 (± 2.4) before surgery. At the final examination time Harris’s score was 91.4 (± 2.5). The rate: very good (75.0%), good (17.4%), average (3.3%), poor (4.3%). There are 02 cases early stem loosening had to stem revision surgery (2.2%). Conclusion: These results show the good initial fixed ability as well as stability when replaced by the Spiron stem.

Cementless Hemiarthroplasty Without Femoral Calcar Reconstruction Versus Cemented Hemiarthroplasty for Unstable Intertrochanteric Fractures in octogenarians

Background The aim of this study was to compare the mid-term outcomes of cementless hemiarthroplasty without femoral calcar reconstruction with cemented hemiarthroplasty in patients aged 80 years or more. Methods From January 2015 to December 2017, 135 patients with unstable intertrochanteric fractures were retrospectively investigated, 70 patients were treated with the cemented hemiarthroplasty while 65 patients were treated with a modular long-stem cementless hemiarthroplasty without rebuilding calcar. Clinical and radiological results were analyzed. Results The 106 alive patients were followed for 62.1 ± 8.3 months, and 29 patients died during the follow-up period. No significant differences were found in terms of demographic and clinical characters of patients, weight training time, postoperative hospital stay length, postoperative ambulatory status and Harris hip score. Patients treated with cementless hemiarthroplasty had a shorter operative time, less estimated blood loss, less amount of blood transfusion and a lower one-year mortality compared with patients treated with cemented hemiarthroplasty. Conclusions Compared with cemented hemiarthroplasty, cementless hemiarthroplasty using a long modular stem without reconstruction of femoral calcar was a good choice for octogenarians with unstable intertrochanteric fractures.

The Role of the Stem-Loop A RNA Promoter in Flavivirus Replication

An essential challenge in the lifecycle of RNA viruses is identifying and replicating the viral genome amongst all the RNAs present in the host cell cytoplasm. Yet, how the viral polymerase selectively recognizes and copies the viral RNA genome is poorly understood. In flaviviruses, the 5′-end of the viral RNA genome contains a 70 nucleotide-long stem-loop, called stem-loop A (SLA), which functions as a promoter for genome replication. During replication, flaviviral polymerase NS5 specifically recognizes SLA to both initiate viral RNA synthesis and to methylate the 5′ guanine cap of the nascent RNA. While the sequences of this region vary between different flaviviruses, the three-way junction arrangement of secondary structures is conserved in SLA, suggesting that viruses recognize a common structural feature to replicate the viral genome rather than a particular sequence. To better understand the molecular basis of genome recognition by flaviviruses, we recently determined the crystal structures of flavivirus SLAs from dengue virus (DENV) and Zika virus (ZIKV). In this review, I will provide an overview of (1) flaviviral genome replication; (2) structures of viral SLA promoters and NS5 polymerases; and (3) and describe our current model of how NS5 polymerases specifically recognize the SLA at the 5′ terminus of the viral genome to initiate RNA synthesis at the 3′ terminus.

The impact of reducing the femoral stem length in total hip arthroplasty during gait

Aim The length of the femoral stem in total hip arthroplasty (THA) is a practical consideration to prevent gait impairment. The aim of this study was to determine if reducing the femoral stem length in THA would lead to impaired gait biomechanics. Methods Patients uniformly with the same brand implant of differing lengths (100 mm vs 140–166 mm) were taken retrospectively from a prospective trial introducing a new short stem. Twelve patients without any other disorder to alter gait besides contralateral differing length stem THA were tested at differing gradients and speed on a validated instrumented treadmill measuring ground reaction forces. An anthropometrically similar group of healthy controls were analysed to compare. Results With the same posterior surgical approach, the offset and length of both hips were reconstructed within 5 mm of each other with an identical mean head size of 36 mm. The short stem was the last procedure for all the hips with gait analysis occurring at a mean of 31 and 79 months postoperatively for the short and long stem THA, respectively. Gait analysis between limbs of both stem lengths demonstrated no statistical difference during any walking condition. In the 90 gait assessments with three loading variables, the short stem was the favoured side 51% of the time compared 49% for the long stem. Conclusion By testing a range of practical walking activities, no lower limb loading differences can be observed by reducing the femoral stem length. A shorter stem demonstrates equivalence in preference during gait when compared to a reputable conventional stem in total hip arthroplasty.