A new strategy has been developed for the oxidant‐ and base‐free dehydrogenative coupling of N‐heterocycles at mild conditions. Under the action of an iridium catalyst, N‐heterocycles undergo ...multiple sp3 CH activation steps, generating a nucleophilic enamine that reacts in situ with various electrophiles to give highly functionalized products. The dehydrogenative coupling can be cascaded with Friedel–Crafts addition, resulting in a double functionalization of the N‐heterocycles.
Regioselectively functionalized quinolines, phenanthrolines, and indoles are obtained by dehydrogenation of N‐heterocycles in the presence of electrophiles. This reaction produces H2 as the only byproduct under mild conditions.
We examine the operations, fairness, and social implications of fair trade certified products. We consider the market for fair trade certified products, which may serve as a substitute to a regular ...product. A fair trade organization chooses standards for the certification, namely, the (unit) premium and minimum fraction of fair trade raw materials, to maximize the total premium transferred to farmers. We analyze the operations of various stakeholders in the fair trade value chain, as well as the role and social welfare of fair trade organizations with different philosophies. We characterize the firms’ entry decision in the fair trade market as well as the resulting market equilibrium. Furthermore, we examine the impact of mainstreaming, i.e., whether to allow large‐scale plantations (often owned by large corporates) to be eligible for fair trade certification or not, which is one of the most discussed topics in the fair trade movement. We also identify the welfare allocation among various stakeholders in the value chain under different certification policies, and thereby address the fairness issue of the fair trade market as well as its resulting social welfare implications. Finally, we obtain a number of policy insights and suggestions to support this nascent marketplace.
Middle East respiratory syndrome coronavirus (MERS-CoV) infection caused severe pneumonia and multiorgan dysfunction and had a higher crude fatality rate (around 50% vs 10%) than SARS coronavirus ...(SARS-CoV) infection. To understand the pathogenesis, we studied viral replication, cytokine/chemokine response, and antigen presentation in MERS-CoV–infected human monocyte–derived macrophages (MDMs) versus SARS-CoV–infected MDMs. Only MERS-CoV can replicate in MDMs. Both viruses were unable to significantly stimulate the expression of antiviral cytokines (interferon α IFN-α and IFN-β) but induced comparable levels of tumor necrosis factor α and interleukin 6. Notably, MERS-CoV induced significantly higher expression levels of interleukin 12, IFN-γ, and chemokines (IP-10/CXCL-10, MCP-1/CCL-2, MIP-1α/CCL-3, RANTES/CCL-5, and interleukin 8) than SARS-CoV. The expression of major histocompatibility complex class I and costimulatory molecules were significantly higher in MERS-CoV–infected MDMs than in SARS-CoV–infected cells. MERS-CoV replication was validated by immunostaining of infected MDMs and ex vivo lung tissue. We conclusively showed that MERS-CoV can establish a productive infection in human macrophages. The aberrant induction of inflammatory cytokines/chemokines could be important in the disease pathogenesis.
This paper estimates the effects of decolonization on bilateral trade by exploiting the end of colonial linkages between the United Kingdom and Hong Kong in 1997 and between Portugal and Macau in ...1999. The two-year gap between these two historical events creates an exogenous time variation in colonial separations across colonial pairs to implement the differences-in-differences strategy. The results show that if a colonial relationship breaks up, then the imports from the former colonial counterpart increases by 42 percent and the post-colonial trade share increases by 0.29 percentage points. Further investigations suggest that the large and positive effects of decolonization on the post-colonial imports are largely operated through mechanisms of income and exchange rate.
The Mass Transit Railway (MTR) serves as the backbone of the Hong Kong public transportation network and continues to be expanded in phases. Nevertheless, occasional but severe disruptions have ...raised concerns about whether the proposed MTR expansions will benefit the system resilience. To assess the value of each stage of MTR network expansion, it is key to identify the distributive effects of new metro lines on both accessibility and resilience. This paper applies the route diversity index, a relatively new accessibility indicator, to assess the effects of new lines and evaluate their spatial distribution, variation, and changes at nodal, dyadic, and network levels. The results indicate that the effects on accessibility and resilience will differ between each stage of MTR expansion. On the accessibility front, the benefits of reduced travel times and increased route diversity will be successively extended to more districts with each MTR expansion, and the spatial equity will also be improved gradually by the expansion, especially in isolated regions such as the northern and western New Territories. In contrast, on the resilience front, although the overall network vulnerability will be reduced, the vulnerability of certain parts of the network will be increased, which might necessitate additional resources to protect these stations. However, some new lines will reduce this vulnerability and provide a complementary solution to enhance network resilience. Overall, the insights from this study could assist in cost-effective resource allocation and informed decision-making for the prioritization of future railway investments and cost-effective resource allocation.
Bismuth oxybromide (BiOBr) nanosheets with fully exposed {001} and {010} facets are synthesized via a facile hydrothermal method. Significant differences in photocatalytic inactivation towards ...Escherichia coli K-12 under visible light irradiation are found to be highly dependent on the dominantly exposed facets. In comparison with BiOBr with dominant {010}-facet (B010) nanosheets, BiOBr with dominant {001}-facet (B001) nanosheets exhibit remarkably higher photocatalytic activity in bacterial inactivation. This superior activity is ascribed to the more favorable separation and transfer of photogenerated electron-hole pairs as well as more oxygen vacancies of B001 nanosheets. Due to the faster production and further accumulation of &z.rad; O sub(2) super(-) and h super(+) within a short time, the VLD photocatalyst of B001 nanosheets can completely inactivate 10 super(7) colony forming unit (CFU) mL super(-1) (i.e. 7-log reduction) bacterial cells within 2 h; while only 1- and 6.5-log reductions of bacterial cells can be achieved within 2 and 6 h, respectively, by B010 nanosheets due to limited amounts of h super(+) and &z.rad; O sub(2) super(-) generated.
We characterized leukemia stem cells (LSC) in chronic phase chronic myelogenous leukemia (CML) using a transgenic mouse model. LSC were restricted to cells with long-term hematopoietic stem cell ...(LTHSC) phenotype. CML LTHSC demonstrated reduced homing and retention in the bone marrow (BM), related to decreased CXCL12 expression in CML BM, resulting from increased G-CSF production by leukemia cells. Altered cytokine expression in CML BM was associated with selective impairment of normal LTHSC growth and a growth advantage to CML LTHSC. Imatinib (IM) treatment partially corrected abnormalities in cytokine levels and LTHSC growth. These results were validated using human CML samples and provide improved understanding of microenvironmental regulation of normal and leukemic LTHSC and their response to IM in CML.
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► CML LSC demonstrate altered proliferation, differentiation and localization ► Abnormal localization is related to leukemia-induced decrease in BM CXCL12 expression ► Altered cytokine expression confers a growth advantage to LSC over normal stem cells ► Micro-environmental changes are partially but not completely corrected by TKI treatment
Diabetic patients are at risk of severe urinary tract infections (UTIs). Due to the emerging resistance rates to fluoroquinolones and β-lactams, we aimed to evaluate the effectiveness of β-lactams ...versus fluoroquinolones as empirical therapy for diabetic patients hospitalized for UTIs.
A retrospective cohort study was conducted in a medical center in Taiwan between 2016 and 2018. Patients with type 2 diabetes, aged ≥20 and hospitalized for UTIs were enrolled. Patients with UTI diagnosis within one year before the admission, co-infections at the admission, or ≥2 pathogens in the urine cultures were excluded. The primary outcome was empiric treatment failure.
298 patients were followed for at least 30 days after the admission. Escherichia coli (61.07%) was the most common pathogen. The resistance rates of the pathogens to levofloxacin were 28.52% and 34.22% according to the historical Clinical and Laboratory Standards Institute (CLSI) breakpoints and the updated 2019 CLSI breakpoints, respectively. The resistance rates of ceftazidime and cefepime were 21.81% and 11.41%, respectively. Empirical β-lactams were associated with less treatment failure compared to fluoroquinolones (adjusted OR = 0.32, 95% CI = 0.17-0.60). Beta-lactams were associated with less treatment failure than fluoroquinolones when appropriatness was determined by the pre-2019 CLSI breakpoints but not the 2019 CLSI breakpoints.
In diabetic patients hospitalized for UTIs, β-lactams were associated with less empiric treatment failure compared to fluoroquinolones when the resistance rate to fluoroquinolone is higher than β-lactams. The updated 2019 CLSI breakpoint for fluoroquinolone was better than pre-2019 CLSI breakpoints to correlate with treatment outcomes for hospitalized UTIs in diabetic patients.
This article presents the electromagnetic and mechanical design as well as experimental testing results for a 9.5:1 gear ratio, series connected, coaxial magnetic gear (MG) for use in a marine ...hydrokinetic generator. A two- and three-dimensional magnetostatic finite-element analysis (FEA) sizing analysis was also conducted and a torque density comparison between using a nested or series MG typology is presented. To achieve a high torque density, a four-segment per pole-pair Halbach rotor assembly with a unique slotted Halbach magnet arrangement was used that enables the Halbach rotor magnets to be more easily assembled, even with dimensional tolerance inaccuracies. A deflection and thermal FEA analysis along with experimental validation test results are presented. The experimentally measured torque and torque density for the MG design are 188.4 N·m and 236.5 N·m/L, respectively.
Chiroptical probes based on circular dichroism (CD) and circularly polarized luminescence (CPL) are crucial for understanding chirality in nature. Lanthanide chiroptical complexes are considered as ...promising candidates for the more sensitive CPL because of their unique optical properties, such as the magnetic dipole-allowed but electric-dipole-forbidden f-f transitions, large pseudo-Stokes shift, and long luminescence lifetime. However, due to the non-directional nature of lanthanide ions which allows variable coordination numbers, the design of their chiral complexes, especially at the supramolecular level, remains a challenge. Recent developments demonstrate the assemblies of chiroptical helices, cages, wheels, knots, and frameworks, which opens up future potential for applications such as in sensing and chiral guest recognition. This review provides the basics of coordination chemistry and photophysics of lanthanide ions, introduces chiroptical characterization, and summarizes the progress on the development of chiroptical lanthanide molecular and supramolecular systems. Perspectives on future development and applications are also discussed.
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Chirality governs the fundamental properties of life, from how our left and right hands complement each other to the drastically different efficacy of two drug enantiomers. Light can be used to characterize chirality by observing its circular polarization when passed through a chiral environment. In this work, the basics of chiroptical properties and the progression of developing lanthanide compounds for chiroptical spectroscopy are reviewed, a wide spectrum of chelate systems and strategies to construct molecular and supramolecular assemblies are summarized, and the relationship between the chiral environment and chiroptical properties is elucidated; moreover, applications based on specific chiral interactions are also reported. The authors are convinced that chiral lanthanide assemblies could help explore new, previously unappreciated avenues in applications that will improve the health and well-being of mankind, benefiting from increased specificity and selectivity.
Chirality is essential in life, and light is employed to understand it. The unique photophysical and magnetic properties of lanthanides allow a sizable signal of circularly polarized luminescence. Herein, we discuss the perspective of this field and summarize the coordination chemistry, chiroptical properties, and applications of lanthanide molecular and supramolecular assemblies.
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