A series of twisted D–π–A type emitters based on the acridine donor unit and CN‐substituted pyridine, pyrimidine, and benzene acceptor units are studied. They not only allow one to systematically ...probe the influence of different acceptor strengths, but also permit one to intriguingly probe the influence of tunable conformations (twist angles) within the acceptor moieties through controlling the orientation of asymmetric heteroaromatic ring relative to the donor component. Intramolecular charge‐transfer transitions are observed in all these compounds and emission wavelengths are widely tunable from deep blue to yellow not only by the general acceptor strength due to the characters of heteroarene and CN‐substitution pattern but also by the subtle control of in‐acceptor conformation (twist angles). Small triplet‐to‐singlet energy gaps (ΔEST) and significant thermally activated delayed fluorescence (TADF) characteristics are obtained in a series of D–π–A compounds with sufficient acceptor strengths and tunable in‐acceptor conformation, yielding a series of efficient blue‐green to yellow TADF emitters with promisingly high photoluminescence quantum yields of 90%–100%. Highly efficient blue‐green to yellow TADF organic light‐emitting diodes (OLEDs) having external quantum efficiencies of up to 23.1%–31.3% are achieved using these efficient TADF emitters, which are among the most efficient TADF OLEDs ever reported.
Efficient blue‐green to yellow thermally activated delayed fluorescence emitters capable of generating 23%–31% electroluminescence external quantum efficiencies are developed adopting the acridine donor unit and cyano (CN)‐substituted pyridine and pyrimidine acceptor units. They permit systematic probing of influences of acceptor strengths and tunable conformations (twist angles) within the acceptor moieties through controlling the orientation of asymmetric heteroaromatic ring.
Since the outbreak of COVID-19, Asians and Asian Americans have been experiencing an uptick of discrimination. With most people experiencing months of lockdowns, social media may become a ...particularly important tool in Asian people's coping with discrimination. Grounded in the multiactivity framework of social media use, this study explored whether experience with discrimination was associated with more social media use among Asian people and how adaptive social media use was for their well-being during COVID-19. A sample of 242 Asians/Asian Americans residing in the United States (
= 32.88,
= 11.13; 48 percent female) completed an online survey. Results showed that more experience of discrimination during COVID-19 was associated with more engagement in social media private messaging, posting/commenting, and browsing, but the activities yielded different implications for subjective well-being. Both social media private messaging and posting/commenting were associated with more perceived social support, which contributed to better subjective well-being. Social media posting/commenting was also related to better subjective well-being through lower worry about discrimination. In contrast, social media browsing was associated with poorer subjective well-being through more worry about discrimination.
Colistin is one of the antibiotics of last resort for the treatment of carbapenem-resistant Klebsiella pneumoniae infection. This study showed that capsular type K64 (50%) and ST11 (53.9%) are the ...prevalent capsular and sequence types in the colistin-resistant strains in Taiwan. The interruption of transcripts (38.5%) and amino acid mutation (15.4%) in mgrB are the major mechanisms contributing to colistin resistance. In addition, novel single amino acid changes in MgrB (Stop48Tyr) and PhoQ (Leu26Pro) were observed to contribute to colistin resistance.
The perceived threat of a contagious virus may lead people to be distrustful of immigrants and out-groups. Since the COVID-19 outbreak, the salient politicized discourses of blaming Chinese people ...for spreading the virus have fueled over 2000 reports of anti-Asian racial incidents and hate crimes in the United States.
The study aims to investigate the relationships between news consumption, trust, intergroup contact, and prejudicial attitudes toward Asians and Asian Americans residing in the United States during the COVID-19 pandemic. We compare how traditional news, social media use, and biased news exposure cultivate racial attitudes, and the moderating role of media use and trust on prejudice against Asians is examined.
A cross-sectional study was completed in May 2020. A total of 430 US adults (mean age 36.75, SD 11.49 years; n=258, 60% male) participated in an online survey through Amazon's Mechanical Turk platform. Respondents answered questions related to traditional news exposure, social media use, perceived trust, and their top three news channels for staying informed about the novel coronavirus. In addition, intergroup contact and racial attitudes toward Asians were assessed. We performed hierarchical regression analyses to test the associations. Moderation effects were estimated using simple slopes testing with a 95% bootstrap confidence interval approach.
Participants who identified as conservatives (β=.08, P=.02), had a personal infection history (β=.10, P=.004), and interacted with Asian people frequently in their daily lives (β=.46, P<.001) reported more negative attitudes toward Asians after controlling for sociodemographic variables. Relying more on traditional news media (β=.08, P=.04) and higher levels of trust in social media (β=.13, P=.007) were positively associated with prejudice against Asians. In contrast, consuming news from left-leaning outlets (β=-.15, P=.001) and neutral outlets (β=-.13, P=.003) was linked to less prejudicial attitudes toward Asians. Among those who had high trust in social media, exposure had a negative relationship with prejudice. At high levels of trust in digital websites and apps, frequent use was related to less unfavorable attitudes toward Asians.
Experiencing racial prejudice among the Asian population during a challenging pandemic can cause poor psychological outcomes and exacerbate health disparities. The results suggest that conservative ideology, personal infection history, frequency of intergroup contact, traditional news exposure, and trust in social media emerge as positive predictors of prejudice against Asians and Asian Americans, whereas people who get COVID-19 news from left-leaning and balanced outlets show less prejudice. For those who have more trust in social media and digital news, frequent use of these two sources is associated with lower levels of prejudice. Our findings highlight the need to reshape traditional news discourses and use social media and mobile news apps to develop credible messages for combating racial prejudice against Asians.
Summary
Klebsiella pneumoniae is an important human pathogen causing opportunistic nosocomial and community‐acquired infections. A major public health concern regarding K. pneumoniae is the ...increasing incidence of multidrug‐resistant strains. Here, we isolated three novel Klebsiella bacteriophages, KN1‐1, KN3‐1 and KN4‐1, which infect KN1, KN3 and K56, and KN4 types respectively. We determined their genome sequences and conducted a comparative analysis that revealed a variable region containing capsule depolymerase‐encoding genes. Recombinant depolymerase proteins were produced, and their enzymatic activity and specificity were evaluated. We identified four capsule depolymerases in these phages that could only digest the capsule types of their respective hosts. Our results demonstrate that the activities of these capsule depolymerases were correlated with the host range of each phage; thus, the capsule depolymerases are host specificity determinants. By generating a capsule mutant, we demonstrate that capsule was essential for phage adsorption and infection. Further, capsule depolymerases can enhance bacterial susceptibility to serum killing. The discovery of these phages and depolymerases lays the foundation for the typing of KN1, KN3, KN4 and K56 Klebsiella and could be useful alternative therapeutics for the treatment of K. pneumoniae infections.
We report three novel Klebsiella phages, KN1‐1, KN3‐1, and KN4‐1, infecting KN1; KN3 and K56; and KN4 types, respectively. We further identified the specific capsule depolymerases of these phages. The discovery of these phages and depolymerases lays the foundation for typing of KN1, KN3, KN4, and K56 Klebsiella and may be used as alternative therapeutics for the treatment of K. pneumoniae infections.
Media coverage and scholarly research have reported that Asian people who reside in the United States have been the targets of racially motivated incidents during the COVID-19 pandemic.
This study ...aimed to examine the types of discrimination and worries experienced by Asians and Asian Americans living in the United States during the pandemic, as well as factors that were associated with everyday discrimination experience and concerns about future discrimination that the Asian community may face.
A cross-sectional online survey was conducted. A total of 235 people who identified themselves as Asian or Asian American and resided in the United States completed the questionnaire.
Our study suggested that up to a third of Asians surveyed had experienced some type of discrimination. Pooling the responses "very often," "often," and "sometimes," the percentages for each experienced discrimination type ranged between 14%-34%. In total, 49%-58% of respondents expressed concerns about discrimination in the future. The most frequently experienced discrimination types, as indicated by responses "very often" and "often," were "people act as if they think you are dangerous" (25/235, 11%) and "being treated with less courtesy or respect" (24/235, 10%). About 14% (32/235) of individuals reported very often, often, or sometimes being threatened or harassed. In addition, social media use was significantly associated with a higher likelihood of experiencing discrimination (β=.18, P=.01) and having concerns about future episodes of discrimination the community may face (β=.20, P=.005). Use of print media was also positively associated with experiencing discrimination (β=.31, P<.001).
Our study provided important empirical evidence regarding the various types of discrimination Asians residing in the United States experienced or worried about during the COVID-19 pandemic. The relationship between media sources and the perception of racial biases in this group was also identified. We noted the role of social media in reinforcing the perception of discrimination experience and concerns about future discrimination among Asians during this outbreak. Our results indicate several practical implications for public health agencies. To reduce discrimination against Asians during the pandemic, official sources and public health professionals should be cognizant of the possible impacts of stigmatizing cues in media reports on activating racial biases. Furthermore, Asians or Asian Americans could also be informed that using social media to obtain COVID-19 information is associated with an increase in concerns about future discrimination, and thus they may consider approaching this media source with caution.
Background. Klebsiella pneumoniae causing community-acquired pyogenic liver abscess complicated with metastatic meningitis and endophthalmitis has emerged recently, most frequently associated with ...the K1 capsular type. Methods. A bacteriophage (NTUH-K2044-K1-1) that infects K. pneumoniae NTUH-K2044 (capsular type K1) was isolated and characterized. Results. The phage infected all K1 strains, and none of the strains with other capsular types. Capsule deletion mutants were not lysed by this phage, suggesting that the capsule was essential for phage infection. Complete genome sequencing revealed the phage was a novel phiKMV-like virus. The gene-encoding capsule depolymerase was identified. The recombinant enzyme demonstrated specific lysis of the K1 capsule. Treatment with the phage or the recombinant enzyme provided significantly increased survival in mice infected with NTUH-K2044 strain, including one treated after the detection of a neck abscess by imaging. No obvious disease was observed after administration of this phage in mice. Phage was retained at detectable levels in liver, spleen, brain, and blood 24 hours after administration in mice. Conclusions. These results demonstrate this phage and its capsule depolymerase exhibit specificity for capsular type K1 and can be used for the diagnosis and treatment of K1 K. pneumoniae infections.
The genome of the multihost bacteriophage ΦK64-1, capable of infecting
capsular types K1, K11, K21, K25, K30, K35, K64, and K69, as well as new capsular types KN4 and KN5, was analyzed and revealed ...that 11 genes (
,
,
,
,
,
,
,
,
,
, and
) encode proteins with amino acid sequence similarity to tail fibers/spikes or lyases.
previously was shown to encode a K64 capsule depolymerase (K64dep). Specific capsule-degrading activities of an additional eight putative capsule depolymerases (S2-4 against K1, S1-1 against K11, S1-3 against K21, S2-2 against K25, S2-6 against K30/K69, S2-3 against K35, S1-2 against KN4, and S2-1 against KN5) was demonstrated by expression and purification of the recombinant proteins. Consistent with the capsular type-specific depolymerization activity of these gene products, phage mutants of
,
,
, or
lost infectivity for KN4, K25, K35, or K30/K69, respectively, indicating that capsule depolymerase is crucial for infecting specific hosts. In conclusion, we identified nine functional capsule depolymerase-encoding genes in a bacteriophage and correlated activities of the gene products to all ten hosts of this phage, providing an example of type-specific host infection mechanisms in a multihost bacteriophage.
We currently identified eight novel capsule depolymerases in a multihost
bacteriophage and correlated the activities of the gene products to all hosts of this phage, providing an example of carriage of multiple depolymerases in a phage with a wide capsular type host spectrum. Moreover, we also established a recombineering system for modification of
bacteriophage genomes and demonstrated the importance of capsule depolymerase for infecting specific hosts. Based on the powerful tool for modification of phage genome, further studies can be conducted to improve the understanding of mechanistic details of
phage infection. Furthermore, the newly identified capsule depolymerases will be of great value for applications in capsular typing.
Background
The COVID-19 outbreak has spurred increasing anti-Asian racism and xenophobia in the United States, which might be detrimental to the psychological well-being of Asian people living in the ...United States.
Objective
We studied three discrimination-related variables, including (1) experience of discrimination, (2) worry about discrimination, and (3) racism-related social media use during the COVID-19 pandemic among Asians in the United States. We examined how these three variables were related to depression, and how the association between racism-related social media use and depression was moderated by personal experience of and worry about racial discrimination.
Methods
A web-based, cross-sectional survey was conducted. A total of 209 people (mean age 33.69, SD 11.31 years; 96/209, 45.93% female) who identified themselves as Asian and resided in the United States were included in the study.
Results
Experience of discrimination (β=.33, P=.001) and racism-related social media use (β=.14, P=.045) were positively associated with depressive symptoms. Worry about discrimination (β=.13, P=.14) was not associated with depression. Worry about discrimination moderated the relationship between racism-related social media use and depression (β=–.25, P=.003) such that a positive relationship was observed among those who had low and medium levels of worry.
Conclusions
The present study provided preliminary evidence that experience of discrimination during the COVID-19 pandemic was a risk factor of depressive symptoms among Asian people in the United States. Meanwhile, racism-related social media use was found to be negatively associated with the well-being of US Asians, and the relationship between social media use and depression was significantly moderated by worry about discrimination. It is critical to develop accessible programs to help US Asians cope with racial discrimination both in real lives and on social media during this unprecedented health crisis, especially among those who have not been mentally prepared for such challenges.
Klebsiella pneumoniae is one of the major pathogens causing hospital-acquired multidrug-resistant infections. The capsular polysaccharide (CPS) is an important virulence factor of K. pneumoniae. With ...78 capsular types discovered thus far, an association between capsular type and the pathogenicity of K. pneumoniae has been observed.
To investigate an initially non-typeable K. pneumoniae UTI isolate NTUH-K1790N, the cps gene region was sequenced. By NTUH-K1790N cps-PCR genotyping, serotyping and determination using a newly isolated capsular type-specific bacteriophage, we found that NTUH-K1790N and three other isolates Ca0507, Ca0421 and C1975 possessed a new capsular type, which we named KN2. Analysis of a KN2 CPS(-) mutant confirmed the role of capsule as the target recognized by the antiserum and the phage. A newly described lytic phage specific for KN2 K. pneumoniae, named 0507-KN2-1, was isolated and characterized using transmission electron microscopy. Whole-genome sequencing of 0507-KN2-1 revealed a 159 991 bp double-stranded DNA genome with a G+C content of 46.7% and at least 154 open reading frames. Based on its morphological and genomic characteristics, 0507-KN2-1 was classified as a member of the Myoviridae phage family. Further analysis of this phage revealed a 3738-bp gene encoding a putative polysaccharide depolymerase. A recombinant form of this protein was produced and assayed to confirm its enzymatic activity and specificity to KN2 capsular polysaccharides. KN2 K. pneumoniae strains exhibited greater sensitivity to this depolymerase than these did to the cognate phage, as determined by spot analysis.
Here we report that a group of clinical strains possess a novel Klebsiella capsular type. We identified a KN2-specific phage and its polysaccharide depolymerase, which could be used for efficient capsular typing. The lytic phage and depolymerase also have potential as alternative therapeutic agents to antibiotics for treating K. pneumoniae infections, especially against antibiotic-resistant strains.
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