214 research outputs found

    Why, or Why Not, Be an Originalist?

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    On November 15, 2019, the Federalist Society hosted the second showcase panel of the 2019 National Lawyers Convention at the Mayflower Hotel in Washington, DC. The topic of the panel was “Why, or Why Not, Be an Originalist?” There are a variety of arguments for following originalism today, such as justifications rooted in language, positivism, sovereignty, and consequences. This panel would look at many normative positions for and against originalism

    Predicting tuberculosis drug resistance with machine learning-assisted Raman spectroscopy

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    Tuberculosis (TB) is the world's deadliest infectious disease, with 1.5 million annual deaths and half a million annual infections. Rapid TB diagnosis and antibiotic susceptibility testing (AST) are critical to improve patient treatment and to reduce the rise of new drug resistance. Here, we develop a rapid, label-free approach to identify Mycobacterium tuberculosis (Mtb) strains and antibiotic-resistant mutants. We collect over 20,000 single-cell Raman spectra from isogenic mycobacterial strains each resistant to one of the four mainstay anti-TB drugs (isoniazid, rifampicin, moxifloxacin and amikacin) and train a machine-learning model on these spectra. On dried TB samples, we achieve > 98% classification accuracy of the antibiotic resistance profile, without the need for antibiotic co-incubation; in dried patient sputum, we achieve average classification accuracies of ~ 79%. We also develop a low-cost, portable Raman microscope suitable for field-deployment of this method in TB-endemic regions

    Developing and pilot testing an oral health screening tool for diabetes care providers

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    Background: People with poorly managed diabetes are at greater risk of periodontal disease. Periodontal disease that is not effectively managed can affect glycaemic levels. Diabetes care providers, including general practitioners and diabetes educators, are encouraged to promote oral health of their clients. However, valid and reliable oral health screening tools that assess the risk of poor oral health, that are easy to administer among non-dental professionals, currently do not exist. Existing screening tools are difficult to incorporate into routine diabetes consultations due to their length. Thus, this study aimed to develop and pilot a short oral health screening tool that would identify risk of existing oral diseases and encourage appropriate referrals to the dental service. Methods: A three-item screening tool was developed after a comprehensive review of the literature and consensus from an expert panel. The tool was then piloted as part of a larger cross-sectional survey of 260 adults with diabetes who were accessing public diabetes clinics at two locations in Sydney, Australia. As part of the survey, participants completed the three-item screening tool and a 14-item validated tool, the Oral Health Impact Profile (OHIP-14), which has been used previously in the preliminary validation of screening tools. Sensitivity and specificity analyses were then undertaken comparing the results of the two tools. Results: A statistically significant correlation was found between the shorter screening tool and the OHIP-14 (rho = 0.453, p < 0.001), indicating adequate validity. The three-item tool had high sensitivity (90.5%, 95% CI 84.9%, 94.7%), with a specificity of 46.3% (95% CI 37.7%, 55.2%). The negative predictive value was 81.4% (95% CI 71.3, 89.3). No single item performed as well regarding sensitivity and negative predictive value when compared to the three items collectively. Conclusions: The three-item screening tool developed was found to be valid and sensitive in identifying risk of poor oral health, requiring oral health referrals, among people with diabetes in this pilot. This is a simple, accessible tool that diabetes care providers could incorporate into their routine consultations. Further validation against comprehensive dental assessments is needed to reassess the tool’s specificity and sensitivity in diverse settings

    anti-Tricyclo­[4.2.1.12,5]deca-3,7-diene-9-endo,10-endo-diol

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    The title compound, C10H12O2, was synthesized as a candidate for further functionalization. The asymmetric unit comprises two independent mol­ecules, both of which are situated on a center of symmetry. Both mol­ecules are involved in a network of hydrogen bonding, with each alcohol group participating in one hydrogen bond as a donor and in a second hydrogen bond as an acceptor

    Calmodulin variant E140G associated with long QT syndrome impairs CaMKIIδ autophosphorylation and L-type calcium channel inactivation

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    Long QT syndrome (LQTS) is a human inherited heart condition that can cause life-threatening arrhythmia including sudden cardiac death. Mutations in the ubiquitous Ca2+-sensing protein calmodulin (CaM) are associated with LQTS, but the molecular mechanism by which these mutations lead to irregular heartbeats is not fully understood. Here, we use a multidisciplinary approach including protein biophysics, structural biology, confocal imaging, and patch-clamp electrophysiology to determine the effect of the disease-associated CaM mutation E140G on CaM structure and function. We present novel data showing that mutant-regulated CaMKIIδ kinase activity is impaired with a significant reduction in enzyme autophosphorylation rate. We report the first high-resolution crystal structure of a LQTS-associated CaM variant in complex with the CaMKIIδ peptide, which shows significant structural differences, compared to the WT complex. Furthermore, we demonstrate that the E140G mutation significantly disrupted Cav1.2 Ca2+/CaM-dependent inactivation, while cardiac ryanodine receptor (RyR2) activity remained unaffected. In addition, we show that the LQTS-associated mutation alters CaM’s Ca2+-binding characteristics, secondary structure content, and interaction with key partners involved in excitation-contraction coupling (CaMKIIδ, Cav1.2, RyR2). In conclusion, LQTS-associated CaM mutation E140G severely impacts the structure-function relationship of CaM and its regulation of CaMKIIδ and Cav1.2. This provides a crucial insight into the molecular factors contributing to CaM-mediated arrhythmias with a central role for CaMKIIδ

    Long QT syndrome-associated calmodulin variants disrupt the activity of the slowly activating delayed rectifier potassium channel.

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    Calmodulin (CaM) is a highly conserved mediator of calcium (Ca2+ )-dependent signalling and modulates various cardiac ion channels. Genotyping has revealed several CaM mutations associated with long QT syndrome (LQTS). LQTS patients display prolonged ventricular recovery times (QT interval), increasing their risk of incurring life-threatening arrhythmic events. Loss-of-function mutations to Kv7.1 (which drives the slow delayed rectifier potassium current, IKs, a key ventricular repolarising current) are the largest contributor to congenital LQTS (>50% of cases). CaM modulates Kv7.1 to produce a Ca2+ -sensitive IKs, but little is known about the consequences of LQTS-associated CaM mutations on Kv7.1 function. Here, we present novel data characterising the biophysical and modulatory properties of three LQTS-associated CaM variants (D95V, N97I and D131H). We showed that mutations induced structural alterations in CaM and reduced affinity for Kv7.1, when compared with wild-type (WT). Using HEK293T cells expressing Kv7.1 channel subunits (KCNQ1/KCNE1) and patch-clamp electrophysiology, we demonstrated that LQTS-associated CaM variants reduced current density at systolic Ca2+ concentrations (1 μm), revealing a direct QT-prolonging modulatory effect. Our data highlight for the first time that LQTS-associated perturbations to CaM's structure impede complex formation with Kv7.1 and subsequently result in reduced IKs. This provides a novel mechanistic insight into how the perturbed structure-function relationship of CaM variants contributes to the LQTS phenotype. KEY POINTS: Calmodulin (CaM) is a ubiquitous, highly conserved calcium (Ca2+ ) sensor playing a key role in cardiac muscle contraction. Genotyping has revealed several CaM mutations associated with long QT syndrome (LQTS), a life-threatening cardiac arrhythmia syndrome. LQTS-associated CaM variants (D95V, N97I and D131H) induced structural alterations, altered binding to Kv7.1 and reduced IKs. Our data provide a novel mechanistic insight into how the perturbed structure-function relationship of CaM variants contributes to the LQTS phenotype

    The effect of sequence context on spontaneous Polζ-dependent mutagenesis in Saccharomyces cerevisiae

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    The Polζ translesion synthesis (TLS) DNA polymerase is responsible for over 50% of spontaneous mutagenesis and virtually all damage-induced mutagenesis in yeast. We previously demonstrated that reversion of the lys2ΔA746 −1 frameshift allele detects a novel type of +1 frameshift that is accompanied by one or more base substitutions and depends completely on the activity of Polζ. These ‘complex’ frameshifts accumulate at two discrete hotspots (HS1 and HS2) in the absence of nucleotide excision repair, and accumulate at a third location (HS3) in the additional absence of the translesion polymerase Polη. The current study investigates the sequence requirements for accumulation of Polζ-dependent complex frameshifts at these hotspots. We observed that transposing 13 bp of identity from HS1 or HS3 to a new location within LYS2 was sufficient to recapitulate these hotspots. In addition, altering the sequence immediately upstream of HS2 had no effect on the activity of the hotspot. These data support a model in which misincorporation opposite a lesion precedes and facilitates the selected slippage event. Finally, analysis of nonsense mutation revertants indicates that Polζ can simultaneously introduce multiple base substitutions in the absence of an accompanying frameshift event

    Hymen reconstruction as pragmatic empowerment? Results of a qualitative study from Tunisia

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    Hymen reconstruction surgery (HR), while ethically controversial, is now available in many countries. Little clinical evidence and hardly any surgical standards support the intervention. Nearly as scarce is social science research exploring women's motivations for the intervention, and health care professionals' justifications for its provision. In order to better understand decision-making processes, we conducted semi-structured interviews in metropolitan Tunis, in 2009, with six women seeking the procedure, four friends who supported such women, four physicians who perform the operation, and one midwife. Health care professionals and patient companions expressed moral ambivalence about HR: although they could comprehend the individual situation of the women, they expressed concern that availability of the procedure might further entrench the patriarchal norms that compel the motivation for seeking HR in the first place. Some women seeking HR shared this concern, but felt it was not outweighed by their personal aims, which were to marry and become mothers, or to overcome past violent sexual experiences. The women felt HR to be uniquely helpful in achieving these aims; all made pragmatic decisions about their bodies in a social environment dominated by patriarchal norms. The link between HR and pervasive gender injustice, including the credible threat of serious social and physical harm to women perceived to have failed to uphold the norm of virginity before marriage, raises questions about health care professionals' responsibility while facing requests for HR. Meaningful regulatory guidance must acknowledge that these genuine harms are at stake; it must do so, however, without resorting to moral double standards. We recommend a reframing of HR as a temporary resource for some women making pragmatic choices in a context of structural gender injustice. We reconfirm the importance of factual sexual and reproductive education, most importantly to counter distorted beliefs that conflate an “intact hymen” with virginity

    Meningococcal disease surveillance in the Asia-Pacific region (2020): The global meningococcal initiative.

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    The degree of surveillance data and control strategies for invasive meningococcal disease (IMD) varies across the Asia-Pacific region. IMD cases are often reported throughout the region, but the disease is not notifiable in some countries, including Myanmar, Bangladesh and Malaysia. Although there remains a paucity of data from many countries, specific nations have introduced additional surveillance measures. The incidence of IMD is low and similar across the represented countries (<0.2 cases per 100,000 persons per year), with the predominant serogroups of Neisseria meningitidis being B, W and Y, although serogroups A and X are present in some areas. Resistance to ciprofloxacin is also of concern, with the close monitoring of antibiotic-resistant clonal complexes (e.g., cc4821) being a priority. Meningococcal vaccination is only included in a few National Immunization Programs, but is recommended for high-risk groups, including travellers (such as pilgrims) and people with complement deficiencies or human immunodeficiency virus (HIV). Both polysaccharide and conjugate vaccines form part of recommendations. However, cost and misconceptions remain limiting factors in vaccine uptake, despite conjugate vaccines preventing the acquisition of carriage.S
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