High on the list of challenges in organic chemistry is the development of new efficient chiral catalysts for enantioselective cycloaddition reactions, which are among the most useful processes in ...chemical synthesis. In the past few decades, various highly enantioselective bifunctional organocatalysts for different versatile cycloaddition reactions have been developed. In most cases, these organocatalytic cycloadditions (
e.g.
4 + 2, 3 + 2, formal 3 + 2, formal 3 + 3, formal 5 + 1, 5 + 2, 1,3-dipolar cycloadditions and Tamura cycloaddition) provide the most convenient and economical routes to nitrogen- and oxygen-containing heterocyclic bioactive molecules. This minireview summarizes the recent developments in this field using chiral bifunctional amine-thiourea and amine-squaramide organocatalysts.
In this review, the recent developments in the field of enantioselective cycloaddition reactions using powerful bifunctional amine-thiourea and amine-squaramide organocatalysts have been described.
Fluorescence nanoscopy, or super-resolution microscopy, has become an important tool in cell biological research. However, because of its usually inferior resolution in the depth direction (50–80 nm) ...and rapidly deteriorating resolution in thick samples, its practical biological application has been effectively limited to two dimensions and thin samples. Here, we present the development of whole-cell 4Pi single-molecule switching nanoscopy (W-4PiSMSN), an optical nanoscope that allows imaging of three-dimensional (3D) structures at 10- to 20-nm resolution throughout entire mammalian cells. We demonstrate the wide applicability of W-4PiSMSN across diverse research fields by imaging complex molecular architectures ranging from bacteriophages to nuclear pores, cilia, and synaptonemal complexes in large 3D cellular volumes.
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•Whole-cell 4Pi single-molecule switching nanoscopy allows 10- to 20-nm 3D resolution•Refined hardware and new data analysis allow imaging of cells as thick as ∼10 μm•Using structure-averaging, the 3D shape of a bacteriophage can be resolved•Wide applicability across diverse research fields is demonstrated
A new super-resolution microscope opens a window deep into cells to image organelles and subcellular structures spanning large volumes.
Background
Widespread vaccination is an essential component of the public health response to the COVID‐19 pandemic, yet vaccine hesitancy remains pervasive. This prospective survey investigation ...aimed to measure the prevalence of vaccine hesitancy in a patient cohort at two urban emergency departments (EDs) and characterize underlying factors contributing to hesitancy.
Methods
Adult ED patients with stable clinical status (Emergency Severity Index 3–5) and without active COVID‐19 disease or altered mental status were considered for participation. Demographic elements were collected as well as reported barriers/concerns related to vaccination and trusted sources of health information. Data were collected in person via a survey instrument proctored by trained research assistants.
Results
A total of 1,555 patients were approached, and 1,068 patients completed surveys (completion rate = 68.7%). Mean (±SD) age was 44.1 (±15.5) years (range = 18–93 years), 61% were female, and 70% were Black. A total of 31.6% of ED patients reported vaccine hesitancy. Of note, 19.7% of the hesitant cohort were health care workers. In multivariable regression analysis, Black race (odds ratio OR = 4.24, 95% confidence interval CI = 2.62 to 6.85) and younger age (age 18–24 years—OR = 4.57, 95% CI = 2.66 to 7.86; age 25–35 years—OR = 5.71, 95% CI = 3.71 to 8.81) were independently associated with hesitancy, to a greater degree than level of education (high school education or less—OR = 2.27, 95% CI = 1.23 to 4.19). Hesitant patients were significantly less likely to trust governmental sources of vaccine information than nonhesitant patients (39.6% vs. 78.9%, p < 0.001); less difference was noted in the domain of trust toward friends/family (51.1% vs. 61.0%, p = 0.004). Hesitant patients also reported perceived vaccine safety concerns and perceived insufficient research.
Conclusions
Vaccine hesitancy is common among ED patients and more common among Black and younger patients, independent of education level. Hesitant patients report perceived safety concerns and low trust in government information sources but less so friends or family. This suggests that strategies to combat hesitancy may need tailoring to specific populations.
This article explores the relationship between distributive justice and transitional justice in post-conflict societies with challenging socio-economic demands. It revisits the main philosophical ...debate on distributive justice in the Anglo-American tradition and traces its reception by academics and practitioners in the fields of development, human rights, and transitional justice. The article shows that transitional justice often sets in motion an opportunity conception of distributive justice that revolves around individual responsibility and deservingness, which entails three negative consequences affecting victims and non-victims alike. First, it justifies an unequal guarantee of their economic and social rights; second, it undermines their self-respect; third, it exhausts public support for victim-oriented policies. In so doing this article distances itself from the existing consensus that transitional justice and distributive justice are different spheres of justice and argues that it is necessary to develop theoretical frameworks that recognize their intimate connection to overcome the pitfalls identified.
The Rum Eastern Layered Intrusion (ELI; Scotland) is an open-system layered intrusion constructed of 16 macro-rhythmic units. Each of the macro-rhythmic units consists of a peridotite base and a ...troctolite (± gabbro) top, previously attributed to the fractional crystallisation of a single magma batch. This classic paradigm has been challenged, however, with evidence presented for the emplacement of peridotite sills in Units 9, 10, and 14, such as cross-cutting relationships, upward-oriented apophyses, and lateral discontinuities. To test whether the other major peridotites within the ELI represent sills, we have carried out new field, petrographic, and mineral chemical analyses of the peridotites in Units 7, 8 and 9. The peridotites display large- and small-scale cross-cutting relationships with the overlying troctolite, indicative of an intrusive relationship. The peridotites also show large-scale coalescence and lateral spatial discontinuities such that the ELI unit divisions become arbitrary. Harrisite layers and Cr-spinel seams found throughout Units 7, 8, and 9 suggest the peridotites were constructed incrementally via repeated injections of picritic magma. Our observations allow for distinct subtypes of peridotite to be defined, separated by intrusive contacts, allowing for their relative chronology to be determined. Older, poikilitic peridotite, rich in clinopyroxene, is truncated by younger, well-layered peridotite, containing abundant harrisite layers. In addition to the new peridotite subtypes defined in this study, we find strong evidence for laterally oriented metasomatism within clinopyroxene-rich wehrlites at the top of the Unit 8 peridotite. The wehrlites and surrounding peridotites record a complex series of metasomatic reactions that transformed thin picrite sills into clinopyroxene-rich wehrlites without any evidence for the sort of vertical melt movement typically posited in layered intrusions. The observations presented in this study from the ELI cannot be reconciled with the classic magma chamber paradigm and are better explained by the emplacement of composite sills into pre-existing feldspathic cumulate (gabbro or troctolite). The evidence for sill emplacement presented here suggests that the layered complex was constructed by a combination of sill emplacement and metasomatism, forming many of the unusual (often clinopyroxene-rich) lithologies that surround the sills. The broad-scale formation of the layered peridotites via incremental sill emplacement, suggested by the occurrence of upward-oriented apophyses, coalescence, and lateral discontinuity, could be applied to much larger ultramafic intrusions, which might have formed by similar mechanisms.
On March 11, 2020, the World Health Organization declared the coronavirus disease 2019 (COVID-19) a pandemic, and in the weeks following, public health organizations, medical associations, and ...governing bodies throughout the world recommended limiting contact with others to "flatten the curve" of COVID-19. Although both ischemic and hemorrhagic strokes have been reported with COVID-19, there has been anecdotal suggestion of an overall decrease in stroke admissions. To date, the effects of any pandemic on telestroke service lines have not been described. The purpose of this cross-sectional analysis of telestroke activations in the 30 days before and after the declaration of the COVID-19 pandemic is to describe the difference in case volumes of telestroke activations, the characteristics of patients, and treatment recommendations between the 2 time frames. We found a 50.0% reduction in total telestroke activations between the predeclaration group (142 patients) and the postdeclaration group (71 patients). There were no statistically significant differences in age (P=.95), sex (P=.10), diagnosis (P=.26), or regional variations (P=.08) in activation volumes. The percentage of patients for whom we recommended urgent stroke treatment with intravenous alteplase, mechanical thrombectomy, or both decreased from 44.4% (28 of 63) to 33.3% (11 of 33). The reasons for the sunstantial decrease in telestroke activations and urgent stroke treatment recommendations are likely multifactorial but nevertheless underscore the importance of continued public health measures to encourage patients and families to seek emergency medical care at the time of symptom onset.
A free‐standing sulfonic acid functionalized graphene oxide (fSGO)‐based electrolyte film is prepared and used in an electrochemical gas sensor, an alcohol fuel cell sensor (AFCS), for the detection ...of alcohol. The fSGO electrolyte film‐based AFCS detects ethanol vapor with excellent response, linearity, and sensitivity, since it possesses a high proton conductivity (58 mS cm−1 at 55 °C). An ethanol detection limit level as low as 25 ppm is achieved and high selectivity for ethanol over acetone is demonstrated. These results do not only show the promising potential of fSGO films in an electrochemical gas sensors, specifically a portable breathalyzer, but also open an alternative pathway to investigate the application of graphene derivatives in the field of gas sensors.
An new type of electrochemical gas sensor, employing a free‐standing film of sulfonic acid functionalized graphene oxide (fSGO) as the solid electrolyte, is developed. Based on the design of alcohol fuel cell sensors (AFCSs), the developed sensor detects alcohol with excellent sensor response, linearity, sensitivity, and selectivity, promising its implementation into portable devices.
Dry eye has gained recognition as a public health problem given its prevalence, morbidity, and cost implications. Dry eye can have a variety of symptoms including blurred vision, irritation, and ...ocular pain. Within dry eye-associated ocular pain, some patients report transient pain whereas others complain of chronic pain. In this review, we will summarize the evidence that chronicity is more likely to occur in patients with dysfunction in their ocular sensory apparatus (ie, neuropathic ocular pain). Clinical evidence of dysfunction includes the presence of spontaneous dysesthesias, allodynia, hyperalgesia, and corneal nerve morphologic and functional abnormalities. Both peripheral and central sensitizations likely play a role in generating the noted clinical characteristics. We will further discuss how evaluating for neuropathic ocular pain may affect the treatment of dry eye-associated chronic pain.
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