958 research outputs found
Zipline-Related Injuries Treated in US EDs, 1997-2012
Purpose
To investigate the epidemiology of zipline-related injuries in the United States. Basic Procedures
The National Electronic Injury Surveillance System database was used to examine non-fatal zipline-related injuries treated in US emergency departments (EDs) from 1997 through 2012. Sample weights were applied to calculate national estimates. Main Findings
From 1997 through 2012, an estimated 16850 (95% CI, 13188-20512) zipline-related injuries were treated in US EDs. The annual injury rate per 1 million population increased by 52.3% from 7.64 (95% CI, 4.86-10.42) injuries in 2009 (the first year with a stable annual estimate) to 11.64 (95% CI, 7.83-15.45) injuries in 2012. Patients aged 0-9 years accounted for 45.0% of injuries, females made up 53.1% of injuries, and 11.7% of patients required hospitalization. Fractures accounted for the largest proportion of injuries (46.7%), and the upper extremities were the most commonly injured body region (44.1%). Falls were the most common mechanism of injury, accounting for 77.3% of injuries. Among cases where the location of the injury event was known, 30.8% of injuries occurred in a residential setting and 69.2% occurred in a public place. Principal Conclusions
This study is the first to characterize the epidemiology of zipline-related injuries using a nationally representative database. The rapid increase in zipline-related injuries in recent years suggests the need for additional safety guidelines and regulations. Commercial ziplines and publicly accessible non-commercial ziplines should be subject to uniform safety standards in all states and jurisdictions across the US, and homemade ziplines should not be used
Parallel quantized charge pumping
Two quantized charge pumps are operated in parallel. The total current
generated is shown to be far more accurate than the current produced with just
one pump operating at a higher frequency. With the application of a
perpendicular magnetic field the accuracy of quantization is shown to be 20
ppm for a current of pA. The scheme for parallel pumping presented in
this work has applications in quantum information processing, the generation of
single photons in pairs and bunches, neural networking and the development of a
quantum standard for electrical current. All these applications will benefit
greatly from the increase in output current without the characteristic decrease
in accuracy as a result of high-frequency operation
The New White Flight
White charter school enclaves—defined as charter schools located in school districts that are thirty percent or less white, but that enroll a student body that is fifty percent or greater white— are emerging across the country. The emergence of white charter school enclaves is the result of a sobering and ugly truth: when given a choice, white parents as a collective tend to choose racially segregated, predominately white schools. Empirical research supports this claim. Empirical research also demonstrates that white parents as a collective will make that choice even when presented with the option of a more racially diverse school that is of good academic quality.
Despite the connection between collective white parental choice and school segregation, greater choice continues to be injected into the school assignment process. School choice assignment policies, particularly charter schools, are proliferating at a substantial rate. As a result, parental choice rather than systemic design is creating new patterns of racial segregation and inequality in public schools. Yet the Supreme Court’s school desegregation jurisprudence insulates racial segregation in schools ostensibly caused by parental choice rather than systemic design from regulation. Consequently, the new patterns of racial segregation in public schools caused by collective white parental choice largely escapes regulation by courts.
This article argues that the time has come to reconsider the legal and normative viability of regulating racial segregation in public schools caused by collective white parental choice. The article makes two important contributions to the legal literature on school desegregation. First, using white charter school enclaves as an example, it documents the ways in which school choice policies are being used to allow whites as a collective to satisfy their preference for segregated predominately white schools. Second, the article sets forth both constitutional and normative arguments for regulating the private choices that result in stark racial segregation patterns in public schools
Root canal morphology of the mandibular second premolar: a systematic review and meta- analysis
Background: The aim of this paper was to systematically review the root canal configuration (RCC) and morphology literature of the mandibular second premolar (Mn2P).
Methods: Systematic research of five electronic databases was performed to identify published literature concerning the root canal configuration (RCC) of the Mn2P up through July 2020. Studies were selected according to predefined search terms and keywords inclusion criteria: “root canal configuration”, “root canal system”, “root canal morphology”, “mandibular second premolar”, “mandibular premolars”, “morphology” and “anatomy”. Further possible studies were identified by cross-referencing and screening the bibliographies of the selected articles.
Results: From 1622 retrieved studies, 44 studies investigating the internal morphology of 17,839 Mn2Ps were included. Most examined Mn2Ps were single-rooted (89.5–100%); two-rooted (0.1–8%) and three-rooted (0.1–3.5%) Mn2Ps at lower frequency. Most frequent RCCs reported were 1–1–1/1 (55.3–99.6%) followed by 1–1–2/2 (0.5–57%) and 2–2–2/2 (0.6–18%). The meta-analysis of seven studies demonstrated that a significantly higher number of RCC type 1–2–1/1 (OR [95%CI] = 2.05 [1.27, 3.33]) and 2–2–2/2 (OR [95%CI] = 2.32 [0.65, 8.63]) were observed in male than in female patients.
Conclusions: Different RCC research methods have been reported. Whereas clearing and radiographs were com- monly used in the past, CBCT has been prevalent in recent years. A globally high frequency of a 1–1–1/1 RCC in the Mn2P has been reported. Nevertheless, the probability that different, more complicated RCCs can appear in Mn2Ps should not be underestimated and, thus, should be taken into consideration when making decisions during an endo- dontic treatment
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Evaluating the Effect of Therapeutic Stem Cells on TRAIL Resistant and Sensitive Medulloblastomas
Mesenchymal stem cells (MSC) are emerging as novel cell-based delivery agents; however, a thorough investigation addressing their therapeutic potential in medulloblastomas (MB) has not been explored to date. In this study, we engineered human MSC to express a potent and secretable variant of a tumor specific agent, tumor necrosis factor-apoptosis-inducing ligand (S-TRAIL) and assessed the ability of MSC-S-TRAIL mediated MB killing alone or in combination with a small molecule inhibitor of histone-deacetylase, MS-275, in TRAIL-sensitive and -resistant MB in vitro and in vivo. We show that TRAIL sensitivity/resistance correlates with the expression of its cognate death receptor (DR)5 and MSC-S-TRAIL induces caspase-3 mediated apoptosis in TRAIL-sensitive MB lines. In TRAIL-resistant MB, we show upregulation of DR4/5 levels when pre-treated with MS-275 and a subsequent sensitization to MSC-S-TRAIL mediated apoptosis. Using intracranially implanted MB and MSC lines engineered with different combinations of fluorescent and bioluminescent proteins, we show that MSC-S-TRAIL has significant anti-tumor effects in mice bearing TRAIL-sensitive and MS-275 pre-treated TRAIL-resistant MBs. To our knowledge, this is the first study that explores the use of human MSC as MB-targeting therapeutic-vehicles in vivo in TRAIL-sensitive and resistant tumors, and has implications for developing effective therapies for patients with medulloblastomas
The Less Well-Known Little Brothers: The SLC9B/NHA Sodium Proton Exchanger Subfamily—Structure, Function, Regulation and Potential Drug-Target Approaches
The SLC9 gene family encodes Na(+)/H(+) exchangers (NHEs), a group of membrane transport proteins critically involved in the regulation of cytoplasmic and organellar pH, cell volume, as well as systemic acid-base and volume homeostasis. NHEs of the SLC9A subfamily (NHE 1–9) are well-known for their roles in human physiology and disease. Much less is known about the two members of the SLC9B subfamily, NHA1 and NHA2, which share higher similarity to prokaryotic NHEs than the SLC9A paralogs. NHA2 (also known as SLC9B2) is ubiquitously expressed and has recently been shown to participate in renal blood pressure and electrolyte regulation, insulin secretion and systemic glucose homeostasis. In addition, NHA2 has been proposed to contribute to the pathogenesis of polycystic kidney disease, the most common inherited kidney disease in humans. NHA1 (also known as SLC9B1) is mainly expressed in testis and is important for sperm motility and thus male fertility, but has not been associated with human disease thus far. In this review, we present a summary of the structure, function and regulation of expression of the SLC9B subfamily members, focusing primarily on the better-studied SLC9B paralog, NHA2. Furthermore, we will review the potential of the SLC9B subfamily as drug targets
Altitudinal Shifts of the Native and Introduced Flora of California in the Context of 20th-Century Warming
Aim: The differential responses of plant species to climate change are of great interest and grave concern for scientists and conservationists. One underexploited resource for better understanding these changes are the records held by herbaria. Using these records to assess the responses of different groups of species across the entire flora of California, we sought to quantify the magnitude of species elevational shifts, to measure differences in shifts among functional groups and between native and introduced species, and to evaluate whether these shifts were related to the conservation of thermal niches.
Location: California.
Methods: To characterize these shifts in California, we used 681,609 georeferenced herbarium records to estimate mean shifts in elevational and climatic space of 4426 plant taxa.We developed and employed a statistical method to robustly analyse the data represented in these records.
Results: We found that 15% of all taxa in California have ranges that have shifted upward over the past century. There are significant differences between range shifts of taxa with different naturalization statuses: 12% of endemic taxa show significant upward range shifts, while a greater proportion (27%) of introduced taxa have shifted upward.We found significant differences between the proportion of significant range shifts across taxa with different seed sizes, but did not find evidence for differences in shift based on life-form (annual versus perennial, herbaceous versus woody).
Main conclusions: Our analyses suggest that introduced species have disproportionately expanded their ranges upward in elevation over the past century when compared with native species.While these shifts in introduced species may not be exclusively driven by climate, they highlight the importance of considering the interacting factors of climate-driven range shifts and invasion to understand how floras are responding in the face of anthropogenic change
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