Synergistic Coordination of Chromatin Torsional Mechanics and Topoisomerase Activity.

DNA replication in eukaryotes generates DNA supercoiling, which may intertwine (braid) daughter chromatin fibers to form precatenanes, posing topological challenges during chromosome segregation. The mechanisms that limit precatenane formation remain unclear. By making direct torque measurements, we demonstrate that the intrinsic mechanical properties of chromatin play a fundamental role in dictating precatenane formation and regulating chromatin topology. Whereas a single chromatin fiber is torsionally soft, a braided fiber is torsionally stiff, indicating that supercoiling on chromatin substrates is preferentially directed in front of the fork during replication. We further show that topoisomerase II relaxation displays a strong preference for a single chromatin fiber over a braided fiber. These results suggest a synergistic coordination-the mechanical properties of chromatin inherently suppress precatenane formation during replication elongation by driving DNA supercoiling ahead of the fork, where supercoiling is more efficiently removed by topoisomerase II. VIDEO ABSTRACT.

Mfd Dynamically Regulates Transcription via a Release and Catch-Up Mechanism.

The bacterial Mfd ATPase is increasingly recognized as a general transcription factor that participates in the resolution of transcription conflicts with other processes/roadblocks. This function stems from Mfd's ability to preferentially act on stalled RNA polymerases (RNAPs). However, the mechanism underlying this preference and the subsequent coordination between Mfd and RNAP have remained elusive. Here, using a novel real-time translocase assay, we unexpectedly discovered that Mfd translocates autonomously on DNA. The speed and processivity of Mfd dictate a "release and catch-up" mechanism to efficiently patrol DNA for frequently stalled RNAPs. Furthermore, we showed that Mfd prevents RNAP backtracking or rescues a severely backtracked RNAP, allowing RNAP to overcome stronger obstacles. However, if an obstacle's resistance is excessive, Mfd dissociates the RNAP, clearing the DNA for other processes. These findings demonstrate a remarkably delicate coordination between Mfd and RNAP, allowing efficient targeting and recycling of Mfd and expedient conflict resolution.

Etoposide promotes DNA loop trapping and barrier formation by topoisomerase II.

Etoposide is a broadly employed chemotherapeutic and eukaryotic topoisomerase II poison that stabilizes cleaved DNA intermediates to promote DNA breakage and cytotoxicity. How etoposide perturbs topoisomerase dynamics is not known. Here we investigated the action of etoposide on yeast topoisomerase II, human topoisomerase IIα and human topoisomerase IIß using several sensitive single-molecule detection methods. Unexpectedly, we found that etoposide induces topoisomerase to trap DNA loops, compacting DNA and restructuring DNA topology. Loop trapping occurs after ATP hydrolysis but before strand ejection from the enzyme. Although etoposide decreases the innate stability of topoisomerase dimers, it increases the ability of the enzyme to act as a stable roadblock. Interestingly, the three topoisomerases show similar etoposide-mediated resistance to dimer separation and sliding along DNA but different abilities to compact DNA and chirally relax DNA supercoils. These data provide unique mechanistic insights into the functional consequences of etoposide on topoisomerase II dynamics.

Elemental Sulfur Promoted Cyclization of Aryl Hydrazones and Aryl Isothiocyanates Yielding 2-Imino-1,3,4-thiadiazoles.

We report a method for using elemental sulfur to facilitate the cyclization of aryl hydrazones and aryl isothiocyanates, affording biorelated 2-imino-1,3,4-thiadiazoles. Reactions progressed in the presence of elemental sulfur, N-methylmorpholine base, and DMSO solvent, while were tolerant of a wide range of functionalities including halogen, nitro, cyano, methylsulfonyl, and heterocyclic groups. The method appears to offer a general pathway for using simple, cheap, and stable reagents to afford triaryl-substituted 2-imino-1,3,4-thiadiazoles under relatively mild conditions.

Cobalt ferrite nanoparticles for annulation of C3-substituted nitroarenes and aryl isothiocyanates.

The synthesis of medicinally relevant N-aryl-substituted 2-aminobenzothiazoles often uses 2-aminothiophenol derivatives, which are not commercially abundant, as starting materials. Herein, we report a method for the annulation of C3-substituted nitroarenes and aryl isothiocyanates towards the synthesis of 2-aminobenzothiazoles. Reactions proceeded in the presence of cobalt ferrite nanoparticles as a catalyst, DABCO as a base, and DMF as a promoter. The cobalt ferrite nanoparticles could be recovered after each run and reused up to 3 times while the product yield was not diminished. Our method appears to be the first example of the direct use of substituted nitroarenes for yielding 2-aminobenzothiazoles.

Synthesis of 2-benzyl benzoxazoles and benzothiazoles via elemental sulfur promoted cyclization of styrenes with 2-nitrophenols and N,N-dialkyl-3-nitroanilines.

Herein we report a method for affording 2-benzyl benzoxazoles from substituted styrenes and 2-nitrophenols. The success of this method relies on the use of simple reagents, namely elemental sulfur and DABCO. A combination of identical reagents was utilized for the annulation of styrenes with N,N-dialkyl-3-nitroanilines to afford 2-benzyl benzothiazoles. Overall, benzoxazoles and benzothiazoles bearing useful functionalities such as halogens, amines, and heterocyclic groups were isolated in moderate to good yields. Our methods are a rare example of divergent transformations of substituted nitroarenes towards 2-benzyl benzoxazoles and benzothiazoles.

Prevalence of metabolic syndrome among Vietnamese adult employees.

BACKGROUND AND AIMS: Metabolic syndrome (MtS) is associated with increased risk of many health disorders, especially cardiovascular diseases. In Vietnam, study examining MtS is meager and especially lacking for the workforce. We estimated the prevalence of MtS and its associated factors among Vietnamese employees. METHODS AND RESULTS: We analyzed secondary data of annual health check of employees of 300 Vietnamese companies from the Vinmec Healthcare System. We used three definitions for MtS: International Diabetes Federation (IDF), National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III), and NCEP ATP III-Asia. Of 57,997 participants evaluated, 48.5 % were males and 66.2 % were younger than 40 years old. The unadjusted MtS prevalence was 8.4 % (IDF), 10.2 % (NCEP ATP III), and 16.0 % (NCEP ATP III-Asia). The age-sex adjusted prevalence of MtS (NCEP ATP III-Asia) was 21.8 % (95 % confidence interval (CI): 21.4 %, 22.2 %). MtS prevalence increased with age, reached 49.6 % for age ≥60. The aging related increase was more remarkable in females than males (prevalence ratio (PR) (95 % CI) for age ≥60 comparing to age <30 years old in males vs. females was 4.0 (3.6, 4.3) vs. 20.1 (17.7, 22.9)). High blood triglyceride (83.4 %) and abdominal obesity (74.5 %) were the predominant contributors to MtS. CONCLUSION: In this relatively young Vietnamese working population, 16 % had MtS with high triglyceride and abdominal obesity being the predominant contributors. These findings emphasize the need for developing effective high triglyceride and abdominal obesity prevention and control programs to curb the emerging epidemic of metabolic disorders in the workforce.

Composed solutions of synchronized patterns in multiplex networks of Kuramoto oscillators.

Networks with different levels of interactions, including multilayer and multiplex networks, can display a rich diversity of dynamical behaviors and can be used to model and study a wide range of systems. Despite numerous efforts to investigate these networks, obtaining mathematical descriptions for the dynamics of multilayer and multiplex systems is still an open problem. Here, we combine ideas and concepts from linear algebra and graph theory with nonlinear dynamics to offer a novel approach to study multiplex networks of Kuramoto oscillators. Our approach allows us to study the dynamics of a large, multiplex network by decomposing it into two smaller systems: one representing the connection scheme within layers (intra-layer), and the other representing the connections between layers (inter-layer). Particularly, we use this approach to compose solutions for multiplex networks of Kuramoto oscillators. These solutions are given by a combination of solutions for the smaller systems given by the intra- and inter-layer systems, and in addition, our approach allows us to study the linear stability of these solutions.

Accessing Diverse Pyridine-Based Macrocyclic Peptides by a Two-Site Recognition Pathway.

Macrocyclic peptides are sought-after molecular scaffolds for drug discovery, and new methods to access diverse libraries are of increasing interest. Here, we report the enzymatic synthesis of pyridine-based macrocyclic peptides (pyritides) from linear precursor peptides. Pyritides are a recently described class of ribosomally synthesized and post-translationally modified peptides (RiPPs) and are related to the long-known thiopeptide natural products. RiPP precursors typically contain an N-terminal leader region that is physically engaged by the biosynthetic proteins that catalyze modification of the C-terminal core region of the precursor peptide. We demonstrate that pyritide-forming enzymes recognize both the leader region and a C-terminal tripeptide motif, with each contributing to site-selective substrate modification. Substitutions in the core region were well-tolerated and facilitated the generation of a wide range of pyritide analogues, with variations in macrocycle sequence and size. A combination of the pyritide biosynthetic pathway with azole-forming enzymes was utilized to generate a thiazole-containing pyritide (historically known as a thiopeptide) with no similarity in sequence and macrocycle size to the naturally encoded pyritides. The broad substrate scope of the pyritide biosynthetic enzymes serves as a future platform for macrocyclic peptide lead discovery and optimization.

Health Within Reach-a Patient-Centered Intervention to Increase Hepatitis B Screening Among Asian Americans: a Randomized Clinical Trial.

BACKGROUND: There are few studies to date of interventions to increase viral hepatitis screening among Asian Americans, who have high rates of chronic hepatitis B (HBV) infection. OBJECTIVE: To develop, implement, and test the efficacy of a mobile application (Hepatitis App) delivered in four languages to increase HBV screening among Asian Americans. DESIGN: Cluster-randomized clinical trial. PARTICIPANTS: Four hundred fifty-two Asian American patients ≥ 18 years of age, who had no prior HBV testing, and received primary care within two healthcare systems in San Francisco, CA. INTERVENTIONS: The intervention group received the Hepatitis App, delivering interactive video education on viral hepatitis in English, Cantonese, Mandarin, or Vietnamese and a provider printout (Provider Alert) and Provider Panel Notification. The comparison group received a mobile application delivering nutrition and physical activity education and Provider Panel Notification. MAIN MEASURES: Primary outcomes were patient-provider discussion about HBV and documentation of a HBV screening test within 3 months post-intervention. Secondary outcome was documentation of an order for a HBV screening test. KEY RESULTS: Participants had a mean age of 57 years and were 64% female, 80% foreign-born, and 44% with limited English fluency. At post-visit, over 80% of intervention participants reported they liked using the Hepatitis App. At 3-month follow-up, the intervention group was more likely than the comparison group (all P < 0.001) to have discussed HBV with their provider (70% vs.16%), have a HBV test ordered (44% vs.10%), and receive a HBV test (38% vs.8%). In multivariable analyses, the intervention odds ratio for HBV test ordering was 7.6 (95% CI: 3.9, 14.8) and test receipt was 7.5 (95% CI: 3.6, 15.5). CONCLUSIONS: A multi-lingual educational intervention using a mobile application in primary care clinics was well received by Asian American patients, enhanced patient-provider communication about HBV, and increased HBV screening. Technology can improve healthcare quality among Asian Americans. TRIAL REGISTRATION: ClinicalTrials.gov NCT02139722 ( https://clinicaltrials.gov/ct2/show/NCT02139722 ).

Metal-Free Annulation of 2-Nitrobenzyl Alcohols and Tetrahydroisoquinolines toward the Divergent Synthesis of Quinazolinones and Quinazolinethiones.

A simple metal-free method for the synthesis of quinazolinones from commercially available 2-nitrobenzyl alcohols and tetrahydroisoquinolines is developed. The reaction conditions were tolerant of an array of functionalities such as halogen, tertiary amine, protected alcohol, and ester groups. Under nearly identical conditions, quinazolinethiones were obtained in the presence of elemental sulfur and suitable mediators.

Patient-reported supportive care needs among Asian American cancer patients.

PURPOSE: Cancer is the leading cause of death for Asian Americans. However, few studies have documented supportive care needs from the perspective of Asian American cancer patients. This study describes the needs reported by Asian American patients with colorectal, liver, or lung cancer over a 6-month period during their treatment. METHODS: Participants were recruited through the Greater Bay Area Cancer Registry and from cancer care providers in San Francisco. Participants self-identified as Asian or Asian American; were age 21 or older; spoke English, Chinese, or Vietnamese; and had stage I-III colon, rectum, liver, or lung cancer. Participants were matched with a language concordant patient navigator who provided support during a 6-month period. Needs were assessed by surveys at baseline, 3, and 6 months. RESULTS: Among 24 participants, 58% were 65 years or older, 42% did not complete high school, and 75% had limited English proficiency (LEP). At baseline, the most prevalent needs were cancer information (79%), nutrition and physical activity (67%), language assistance (54%), and daily living (50%). At the 3- and 6-month follow-up surveys, there was a higher reported need for mental health resources and healthcare access among participants. CONCLUSION: In this pilot study of Asian American cancer patients who predominantly had LEP, participants reported many needs, with cancer information and language assistance as the most prominent. The findings highlight the importance of culturally and linguistically appropriate patient navigators in addressing supportive care needs among cancer patients with LEP. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT03867916.

Exploring factors associated with hepatitis B screening in a multilingual and diverse population.

BACKGROUND: Racial/ethnic minorities bear a disproportionate burden of hepatitis B virus (HBV) infection and disease. Disparities in HBV screening contribute to worse outcomes for communities of color. We examined the impact of race/ethnicity, language preference, and having a usual place of care on HBV screening in a multilingual, urban cohort. METHODS: We used questions from the Health Information National Trends Survey and added validated questions about healthcare access and health literacy. We administered this survey in English, Spanish, and Chinese to a selected convenience sample of San Francisco city/county residents in 2017, with pre-specified targets for populations with known cancer disparities: 25% Spanish-speaking, 25% Chinese-speaking, and 25% Black Americans. Using weighted multivariable logistic regression analyses, we assessed how race/ethnicity, language preference, and having a usual place of care impacts self-report of HBV screening. RESULTS: Overall, 1027 participants completed the survey (50% of surveys administered in English, 25% in Spanish, and 25% in Chinese). Only 50% of participants reported HBV screening. In multivariable analysis, Black (OR = 0.20, 95% CI 0.08-0.49), Latinx (OR = 0.33, 95% CI 0.13-0.85), Asian (OR = 0.31, 95% CI 0.10, 0.94), and 'Other' race/ethnicity (OR = 0.17, 95% CI 0.05-0.53) respondents had lower odds of HBV screening compared to non-Hispanic White respondents. Participants who had insurance had increased odds of HBV screening (OR = 2.70, 95% CI 1.48-4.93). CONCLUSIONS: HBV screening disparities persist for Black Americans, Asian Americans, Latinx, and the uninsured. Future studies should explore reasons why current strategies have not been implemented or are not successful, particularly in addressing racial/ethnic and insurance disparities.

Effect of a media intervention on hepatitis B screening among Vietnamese Americans.

Objective: There is a lack of controlled studies of community-wide interventions to increase screening for hepatitis B (HBV) among Asian Americans, particularly Vietnamese Americans, who disproportionately suffer from HBV-related illnesses. The objective of our study was to develop, implement, and evaluate the effectiveness of a media campaign to promote HBV screening among Vietnamese Americans.Design: We designed and implemented a three-year media campaign promoting HBV screening among Vietnamese Americans. Evaluation consisted of cross-sectional pre- and post-intervention population-based telephone surveys of Vietnamese Americans adults age 18-64 who spoke English or Vietnamese and lived in the Northern California (intervention) or Greater Washington, D.C. (comparison) communities in 2007 or 2011. Statistical analysis was completed in 2012. The main outcome was self-report of HBV testing, defined as participants answering 'Yes' to the question: 'Have you ever had a blood test to check for hepatitis B?'Results: The sample sizes at pre- and post-intervention were 1,704 and 1,666, respectively. Both communities reported increased exposure to HBV-related booklets, radio and television advertisements, and websites. Only the intervention community reported increased exposure to newspaper elements. HBV screening increased in both communities (intervention: 65.3% to 73.1%, p < 0.01, comparison: 57.7% to 66.0%, p < 0.01). In multivariable analyses, there was no intervention effect. In both communities, exposure to media elements (Odds Ratio 1.26 [95% Confidence Interval: 1.21, 1.31] for each additional element) was significantly associated with screening.Conclusions: Among Vietnamese Americans in 2 large communities, HBV screening rates were sub-optimal. Screening increased in both the intensive media intervention and comparison communities, and exposure to HBV-related media messages was associated with increased screening. Efforts to address HBV screening among Vietnamese Americans should include mass media messaging.

Geometry unites synchrony, chimeras, and waves in nonlinear oscillator networks.

One of the simplest mathematical models in the study of nonlinear systems is the Kuramoto model, which describes synchronization in systems from swarms of insects to superconductors. We have recently found a connection between the original, real-valued nonlinear Kuramoto model and a corresponding complex-valued system that permits describing the system in terms of a linear operator and iterative update rule. We now use this description to investigate three major synchronization phenomena in Kuramoto networks (phase synchronization, chimera states, and traveling waves), not only in terms of steady state solutions but also in terms of transient dynamics and individual simulations. These results provide new mathematical insight into how sophisticated behaviors arise from connection patterns in nonlinear networked systems.

Effect of ontological insecurity on vaccination behavior against COVID-19: a hospital-based cross-sectional study.

OBJECTIVE: Coronavirus disease 2019 (COVID-19) has brought great uncertainty to our society and it may have disrupted people's ontological security. Consequently, this hospital-based study concerns the impact of ontological insecurity on vaccination behavior against COVID-19. STUDY DESIGN: This cross-sectional study was conducted among hospital inpatients. METHODS: A questionnaire survey addressing inpatient ontological insecurity and vaccination behavior against COVID-19 was administered in Taizhou, China. A total of 1223 questionnaires were collected; specifically, 1185 of them were credible, for a validity rate of 96.9%. RESULTS: The score of ontological insecurity was 13.27 ± 7.84, which was higher in participants who did not recommend vaccination for others than those who did (12.95 ± 8.25 vs 14.00 ± 6.78, P = 0.022). There was no difference between the vaccinated and unvaccinated groups (13.22 ± 7.96 vs 13.35 ± 7.67, P = 0.779). Lower ontological insecurity (odds ratio [OR] = 1.40, 95% confidence interval [CI]: 1.08-1.81) and being inoculated with COVID-19 vaccines (OR = 2.17, 95% CI: 1.67-2.82) were significantly associated with recommendation of COVID-19 vaccines to others after adjusting for sex, age, education, and occupation. Associations between low ontological insecurity and recommendations for COVID-19 vaccines were observed in men, adults aged 18-59 years, non-farmers, and vaccine recipients. CONCLUSIONS: This study suggests that the ontological insecurity of participants affects their behavior of recommending the COVID-19 vaccination to others rather than getting vaccinated themselves. This promotion of vaccination can be considered from the perspective of improving ontological security in China.

Surgically assisted rapid palatal expansion (SARPE): three-dimensional superimposition on cranial base.

OBJECTIVES: To evaluate dental and skeletal changes caused by surgically assisted rapid palatal expansion (SARPE) using the superimposition of three-dimensional cone-beam computed tomography (CBCT) images on the cranial base. MATERIAL AND METHODS: This is a retrospective quasi-experiment before-and-after study using a convenience sample. Twenty-four adult patients (13 male and 11 female) were evaluated before SARPE (T0), immediately after expansion (T1), and after 6 months of retention (T2). CBCT scans were superimposed on the anterior cranial base using voxel-based registration. Measurements from different reference points were used for comparisons between times. RESULTS: At T1, all teeth had significant buccal tipping. At T2, most teeth remained in the same position as at T1, except the first premolar and the first molar, whose buccal roots moved slightly. The amount of bony expansion was 65 to 70% of the amount of tooth movement. The A point and maxillary incisors moved anteriorly from T0 to T1 and T2 (p < 0.0001). Inter-nasal distance had increased significantly at T1 (p < 0.0001) and remained stable at T2 (p = 0.478). No expansion was achieved at the zygomatic arch (p = 0.114). CONCLUSION: SARPE promoted substantial buccal tipping of posterior teeth and some bone displacement; it also moved the maxilla and teeth forward and increased nasal width. CLINICAL RELEVANCE: No other clinical studies have evaluated dental and skeletal changes caused by SARPE using superimposition of 3D CBCT images on the cranial base. This study findings may help clinical dentists plan treatments using safe and reliable information.

Death Toll of COVID-19 on Asian Americans: Disparities Revealed.

The coronavirus disease 2019 (COVID-19) pandemic has underscored the structural inequities facing communities of color and its consequences in lives lost. However, little is known about the COVID-related disparities facing Asian Americans amidst the heightened racism and violence against this community. We analyze the mortality toll of COVID-19 on Asian Americans using multiple measures. In 2020, one in seven Asian American deaths was attributable to COVID-19. We find that while Asian Americans make up a small proportion of COVID-19 deaths in the USA, they experience significantly higher excess all-cause mortality (3.1 times higher), case fatality rate (as high as 53% higher), and percentage of deaths attributed to COVID-19 (2.1 times higher) compared to non-Hispanic Whites. Mounting evidence suggest that disproportionately low testing rates, greater disease severity at care presentation, socioeconomic factors, and racial discrimination contribute to the observed disparities. Improving data reporting and uniformly confronting racism are key components to addressing health inequities facing communities of color.

Copper-catalyzed synthesis of pyrido-fused quinazolinones from 2-aminoarylmethanols and isoquinolines or tetrahydroisoquinolines.

Pyrido-fused quinazolinones were synthesized via copper-catalyzed cascade C(sp2)-H amination and annulation of 2-aminoarylmethanols with isoquinolines or pyridines. The transformation proceeded readily in the presence of a commercially available CuCl2 catalyst with molecular oxygen as a green oxidant. Moreover, the dehydrogenative cross-coupling of 2-aminoarylmethanols with tetrahydroisoquinolines was explored, in which CuBr exhibited higher catalytic activity than CuCl2. Broad substrate scope with good tolerance of functionalities was observed under the optimized reaction conditions. The bioactive naturally occurring alkaloid rutaecarpine could be obtained by this strategy. The remarkable feature of this protocol is that complicated heterocyclic structures are readily achieved in a single synthetic step from easily accessible reactants and catalysts. This pathway to pyrido-fused quinazolinones would be complementary to existing protocols.