Results from Rapid Testing of Space-based Mobile Network Technology

Lynk (formerly UbiquitiLink) is building a network of small satellites to provide affordable cellular coverage to unmodified cellular devices, enabling messaging, data, IoT, and emergency communications everywhere on the planet. This paper will discuss the details of the approach for Lynk\u27s technology development program to-date. Since December 2018, test spacecraft Lynk 01, Lynk 02, Lynk 03, and Lynk 04 have all been launched to orbit and tested. Lynk flies new space hardware every ~6 months to incrementally space qualify our LEO-to-phone space technologies. Each 6-month cycle includes the design, fabrication, assembly, and test of a new spacecraft iteration before handover for launch. During initial technology development, Lynk has leveraged the ISS and NASA\u27s cargo resupply (CRS) missions; these missions offer frequent and affordable access to orbit in support of Lynk’s rapid prototyping and agile development timelines. These spacecraft have enabled Lynk to conduct the world’s first orbiting cell tower demonstrations for a space-based cellular network. In a very short period, the test program has already successfully demonstrated critical functionalities needed for satellite-to-phone messaging initially using GSM technology; LTE is next. Tests have demonstrated connectivity from a satellite to unmodified cellular devices using frequencies already in use by common cellular phones. The discussion of technical achievements will include: link budget verification and payload validation; software development to project and coordinate test site overpasses; transmission from satellite over specific test sites; and demonstration of a cellular network in a box creating a private network cell within a beam focused on the Earth. A review of the challenges experienced, the implications for the testing program, and the solutions implemented will be included

Vascular injuries after minor blunt upper extremity trauma: pitfalls in the recognition and diagnosis of potential "near miss" injuries

<p>Abstract</p> <p>Background</p> <p>Low energy trauma to the upper extremity is rarely associated with a significant vascular injury. Due to the low incidence, a high level of suspicion combined with appropriate diagnostic algorithms are mandatory for early recognition and timely management of these potentially detrimental injuries.</p> <p>Methods</p> <p>Review of the pertinent literature, supported by the presentation of two representative "near miss" case examples.</p> <p>Results</p> <p>A major diagnostic pitfall is represented by the insidious presentation of significant upper extremity arterial injuries with intact pulses and normal capillary refill distal to the injury site, due to collateral perfusion. Thus, severe vascular injuries may easily be missed or neglected at the upper extremity, leading to a long-term adverse outcome with the potential need for a surgical amputation.</p> <p>Conclusion</p> <p>The present review article provides an outline of the diagnostic challenges related to these rare vascular injuries and emphasizes the necessity for a high level of suspicion, even in the absence of a significant penetrating or high-velocity trauma mechanism.</p

The Prevalence and Clinical Implications of Comorbid Back Pain in Shoulder Instability: A Multicenter Orthopaedic Outcomes Network (MOON) Shoulder Instability Cohort Study.

Background:Understanding predictors of pain is critical, as recent literature shows that comorbid back pain is an independent risk factor for worse functional and patient-reported outcomes (PROs) as well as increased opioid dependence after total joint arthroplasty. Purpose/Hypothesis:The purpose of this study was to evaluate whether comorbid back pain would be predictive of pain or self-reported instability symptoms at the time of stabilization surgery. We hypothesized that comorbid back pain will correlate with increased pain at the time of surgery as well as with worse scores on shoulder-related PRO measures. Study Design:Cross-sectional study; Level of evidence, 3. Methods:As part of the Multicenter Orthopaedic Outcomes Network (MOON) Shoulder Instability cohort, patients consented to participate in pre- and intraoperative data collection. Demographic characteristics, injury history, preoperative PRO scores, and radiologic and intraoperative findings were recorded for patients undergoing surgical shoulder stabilization. Patients were also asked, whether they had any back pain. Results:The study cohort consisted of 1001 patients (81% male; mean age, 24.1 years). Patients with comorbid back pain (158 patients; 15.8%) were significantly older (28.1 vs 23.4 years; P &lt; .001) and were more likely to be female (25.3% vs 17.4%; P = .02) but did not differ in terms of either preoperative imaging or intraoperative findings. Patients with self-reported back pain had significantly worse preoperative pain and shoulder-related PRO scores (American Shoulder and Elbow Surgeons score, Western Ontario Shoulder Instability Index) (P &lt; .001), more frequent depression (22.2% vs 8.3%; P &lt; .001), poorer mental health status (worse scores for the RAND 36-Item Health Survey Mental Component Score, Iowa Quick Screen, and Personality Assessment Screener) (P &lt; .01), and worse preoperative expectations (P &lt; .01). Conclusion:Despite having similar physical findings, patients with comorbid back pain had more severe preoperative pain and self-reported symptoms of instability as well as more frequent depression and lower mental health scores. The combination of disproportionate shoulder pain, comorbid back pain and mental health conditions, and inferior preoperative expectations may affect not only the patient's preoperative state but also postoperative pain control and/or postoperative outcomes

Do nuclear DNA and dental nonmetric data produce similar reconstructions of regional population history? An example from modern coastal Kenya

This study investigates whether variants in dental morphology and nuclear DNA provide similar patterns of intergroup affinity among regional populations using biological distance (biodistance) estimates. Many biodistance studies of archaeological populations use skeletal variants in lieu of ancient DNA, based on the widely accepted assumption of a strong correlation between phenetic- and genetic-based affinities. Within studies of dental morphology, this assumption has been well supported by research on a global scale but remains unconfirmed at a more geographically restricted scale. Paired genetic (42 microsatellite loci) and dental (nine crown morphology traits) data were collected from 295 individuals among four contemporary Kenyan populations, two of which are known ethnically as “Swahili” and two as “Taita;” all have welldocumented population histories. The results indicate that biodistances based on genetic data are correlated with those obtained from dental morphology. Specifically, both distance matrices indicate that the closest affinities are between population samples within each ethnic group. Both also identify greater divergence among samples from the different ethnic groups. However, for this particular study the genetic data may provide finer resolution at detecting overall among-population relationships

Anterior cruciate ligament reconstruction with concomitant meniscal repair: Is graft choice predictive of meniscal repair success?

Background: When meniscal repair is performed during anterior cruciate ligament (ACL) reconstruction (ACLR), the effect of ACL graft type on meniscal repair outcomes is unclear. Hypothesis: The authors hypothesized that meniscal repairs would fail at the lowest rate when concomitant ACLR was performed with bone--patellar tendon--bone (BTB) autograft. Study Design: Cohort study; Level of evidence, 3. Methods: Patients who underwent meniscal repair at primary ACLR were identified from a longitudinal, prospective cohort. Meniscal repair failures, defined as any subsequent surgical procedure addressing the meniscus, were identified. A logistic regression model was built to assess the association of graft type, patient-specific factors, baseline Marx activity rating score, and meniscal repair location (medial or lateral) with repair failure at 6-year follow-up. Results: A total of 646 patients were included. Grafts used included BTB autograft (55.7%), soft tissue autograft (33.9%), and various allografts (10.4%). We identified 101 patients (15.6%) with a documented meniscal repair failure. Failure occurred in 74 of 420 (17.6%) isolated medial meniscal repairs, 15 of 187 (8%) isolated lateral meniscal repairs, and 12 of 39 (30.7%) of combined medial and lateral meniscal repairs. Meniscal repair failure occurred in 13.9% of patients with BTB autografts, 17.4% of patients with soft tissue autografts, and 19.4% of patients with allografts. The odds of failure within 6 years of index surgery were increased more than 2-fold with allograft versus BTB autograft (odds ratio = 2.34 [95% confidence interval, 1.12-4.92]; Conclusion: Meniscal repair location (medial vs lateral) and baseline activity level were the main drivers of meniscal repair outcomes. Graft type was ranked third, demonstrating that meniscal repairs performed with allograft were 2.3 times more likely to fail compared with BTB autograft. There was no significant difference in failure rates between BTB versus soft tissue autografts. Registration: NCT00463099 (ClinicalTrials.gov identifier)

Mapping Meaning : Critical Cartographies for Participatory Water Management in Taita Hills, Kenya

Participation of local people is often neglected in natural resource management, which leads to failure to understand the social aspects and historical construction of environmental problems. Participatory mapping can enhance the communication of local spatial knowledge for management processes and challenge the official maps and other spatial representations produced by state authorities and scientists. In this study, we analyze what kind of social meanings can be revealed through a multimethod participatory mapping process focusing on water resources in Taita Hills, Kenya. The participatory mapping clearly complicates the simplified image of the physical science mappings, typically depicting natural water supply, by addressing the impacts of contamination, inadequate infrastructure, poverty, distance to the sources, and restrictions in their uses on people's access to water. Moreover, this shared exercise is able to trigger discussion on issues that cannot always be localized but still contribute to place making. Local historical accounts reveal the social and political drivers of the current water-related problems, making explicit the political ecology dynamics in the area.Peer reviewe

Immunopurification of Pathological Prion Protein Aggregates

Background: Prion diseases are fatal neurodegenerative disorders that can arise sporadically, be genetically inherited or acquired through infection. The key event in these diseases is misfolding of the cellular prion protein (PrP) into a pathogenic isoform that is rich in β-sheet structure. This conformational change may result in the formation of PrP, the prion isoform of PrP, which propagates itself by imprinting its aberrant conformation onto PrP molecules. A great deal of effort has been devoted to developing protocols for purifying PrP for structural studies, and testing its biological properties. Most procedures rely on protease digestion, allowing efficient purification of PrP27-30, the protease-resistant core of PrP. However, protease treatment cannot be used to isolate abnormal forms of PrP lacking conventional protease resistance, such as those found in several genetic and atypical sporadic cases. Principal Findings: We developed a method for purifying pathological PrP molecules based on sequential centrifugation and immunoprecipitation with a monoclonal antibody selective for aggregated PrP. With this procedure we purified full-length PrP and mutant PrP aggregates at electrophoretic homogeneity. PrP purified from prion-infected mice was able to seed misfolding of PrP in a protein misfolding cyclic amplification reaction, and mutant PrP aggregates from transgenic mice were toxic to cultured neurons. Significance: The immunopurification protocol described here isolates biologically active forms of aggregated PrP. These preparations may be useful for investigating the structural and chemico-physical properties of infectious and neurotoxic PrP aggregates