Assessing the American public's preferences for reforms to teen driving licensure systems: a discrete choice experiment.

OBJECTIVES: To analyse factors influencing the American public's preferences for changes to teenage driver licensing requirements. METHODS: We employed a discrete choice experiment (DCE) with 808 participants from National Opinion Research Center's AmeriSpeak panel to assess preferences for two existing elements (on-road testing and intermediate licensure period) and a new feature (driver monitoring with telematics during the intermediate licensure period) of licensing system. Multinomial and mixed logit models were used to estimate preference weights, marginal rates of substitution and the relative importance of each attribute. RESULTS: Among 730 respondents who completed all DCE choice tasks, we found robust support for changes to teenage driver licensing requirements, with preferences varying by individual characteristics. Respondents expressed a high baseline support for changes to teen driving licensure policies. They favoured testing, prioritising easy tests and opposed prolonged driver monitoring and extended intermediate licensure periods. Baseline preference weights exhibited substantial heterogeneity, emphasising the diversity of public preferences. The marginal rates of substitution revealed a preference for extended driver monitoring over an extended intermediate licensure period. An easy test was valued at 2.85 times more than a hard one. The most influential attributes were the length of intermediate licence period and testing requirements, with the former twice as important. CONCLUSIONS: Our study found robust support for reforms to teenage driver licensing requirements, favouring easier on-road driving tests over an extended period of intermediate licensure and driver monitoring. Public preferences for licensing systems need to be balanced with the broader policy objectives including optimising mobility and maximising safety.

The Future of Road Safety: Challenges and Opportunities.

Policy Points Traditional approaches to addressing motor vehicle crashes are yielding diminishing returns. A comprehensive strategy known as the Safe Systems approach shows promise in both advancing safety and equity and reducing motor vehicle crashes. In addition, a range of emerging technologies, enabled by artificial intelligence, such as automated vehicles, impairment detection and telematics hold promise to advance road safety. Ultimately, the transportation system will need to evolve to provide the safe, efficient, and equitable movement of people and goods without reliance on private vehicle ownership, towards encouraging walking, bicycling and the use of public transportation.

The role of nitrogen-responsive regulators in controlling inorganic polyphosphate synthesis in Escherichia coli.

Inorganic polyphosphate (polyP) is synthesized by bacteria under stressful environmental conditions and acts by a variety of mechanisms to promote cell survival. While the kinase that synthesizes polyP (PPK, encoded by the ppk gene) is well known, ppk transcription is not activated by environmental stress and little is understood about how environmental stress signals lead to polyP accumulation. Previous work has shown that the transcriptional regulators DksA, RpoN (σ54) and RpoE (σ24) positively regulate polyP production, but not ppk transcription, in Escherichia coli. In this work, we examine the role of the alternative sigma factor RpoN and nitrogen starvation stress response pathways in controlling polyP synthesis. We show that the RpoN enhancer binding proteins GlnG and GlrR impact polyP production, and uncover a new role for the nitrogen phosphotransferase regulator PtsN (EIIANtr) as a positive regulator of polyP production, acting upstream of DksA, downstream of RpoN and apparently independently of RpoE. However, neither these regulatory proteins nor common nitrogen metabolites appear to act directly on PPK, and the precise mechanism(s) by which polyP production is modulated after stress remain(s) unclear. Unexpectedly, we also found that the genes that impact polyP production vary depending on the composition of the rich media in which the cells were grown before exposure to polyP-inducing stress. These results constitute progress towards deciphering the regulatory networks driving polyP production under stress, and highlight the remarkable complexity of this regulation and its connections to a broad range of stress-sensing pathways.

CtIP maintains stability at common fragile sites and inverted repeats by end resection-independent endonuclease activity.

Chromosomal rearrangements often occur at genomic loci with DNA secondary structures, such as common fragile sites (CFSs) and palindromic repeats. We developed assays in mammalian cells that revealed CFS-derived AT-rich sequences and inverted Alu repeats (Alu-IRs) are mitotic recombination hotspots, requiring the repair functions of carboxy-terminal binding protein (CtBP)-interacting protein (CtIP) and the Mre11/Rad50/Nbs1 complex (MRN). We also identified an endonuclease activity of CtIP that is dispensable for end resection and homologous recombination (HR) at I-SceI-generated "clean" double-strand breaks (DSBs) but is required for repair of DSBs occurring at CFS-derived AT-rich sequences. In addition, CtIP nuclease-defective mutants are impaired in Alu-IRs-induced mitotic recombination. These studies suggest that an end resection-independent CtIP function is important for processing DSB ends with secondary structures to promote HR. Furthermore, our studies uncover an important role of MRN, CtIP, and their associated nuclease activities in protecting CFSs in mammalian cells.

State and city laws governing the use of child restraint systems in rideshare vehicles and taxicabs: requirements and responsibility.

OBJECTIVES: To identify, describe and critique state and local policies related to child passenger safety in for-hire motor vehicles including ridesharing and taxis. METHODS: We used standard legal research methods to collect policies governing the use of child restraint systems (CRS) in rideshare and taxi vehicles for all 50 states and the 50 largest cities in the USA. We abstracted the collected policies to determine whether the policy applies to specific vehicles, requires specific safety restraints in those vehicles, lists specific requirements for use of those safety restraints, seeks to enhance compliance and punishes noncompliance. RESULTS: All 50 states have policies that require the use of CRS for children under a certain age, weight or height. Seven states exempt rideshare vehicles and 28 states exempt taxis from their CRS requirements. Twelve cities have relevant policies with eight requiring CRS in rideshare vehicles, but not taxis, and two cities requiring CRS use in both rideshare vehicles and taxis. CONCLUSION: Most states require CRS use in rideshare vehicles, but not as many require CRS use in taxis. Though states describe penalties for drivers who fail to comply with CRS requirements, these penalties do not actually facilitate the use of CRS in rideshare or taxis. Furthermore, there is ambiguity in the laws about who is responsible for the provision and installation of the restraints. To prevent serious or fatal injuries in children, policy-makers should adopt policies that require, incentivise and facilitate the use of CRS in rideshare vehicles and taxis.

Effect of Combined Clinical Practice Guideline and Electronic Order Set Implementation on Febrile Infant Evaluation and Management.

OBJECTIVE: Management of febrile infants 60 days and younger for suspected serious infection varies widely. Clinical practice guidelines (CPGs) are intended to improve clinician adherence to evidence-based practices. In 2011, a CPG for managing febrile infants was implemented in an urban children's hospital with simultaneous release of an electronic order set and algorithm to guide clinician decisions for managing infants for suspected serious bacterial infection. The objective of the present study was to determine the association of CPG implementation with order set use, clinical practices, and clinical outcomes. METHODS: Records of febrile infants 60 days and younger from February 1, 2009, to January 31, 2013, were retrospectively reviewed. Clinical documentation, order set use, clinical management practices, and outcomes were compared pre-CPG and post-CPG release. RESULTS: In total, 1037 infants pre-CPG and 930 infants post-CPG implementation were identified. After CPG release, more infants 29 to 60 days old underwent lumbar puncture (56% vs 62%, P = 0.02). Overall antibiotic use and duration of antibiotic use decreased for infants 29 to 60 days (57% vs 51%, P = 0.02). Blood culture and urine culture obtainment remained unchanged for older infants. Diagnosed infections, hospital readmissions, and length of stay were unchanged. Electronic order sets were used in 80% of patient encounters. CONCLUSIONS: Antibiotic use and lumbar puncture performance modestly changed in accordance with CPG recommendations provided in the electronic order set and algorithm, suggesting that the presence of embedded prompts may affect clinician decision-making. Our results highlight the potential usefulness of these decision aids to improve adherence to CPG recommendations.

Comparison of the ID Now Influenza A & B 2, Cobas Influenza A/B, and Xpert Xpress Flu Point-of-Care Nucleic Acid Amplification Tests for Influenza A/B Virus Detection in Children.

Early diagnosis of influenza (Flu) is critical for patient management and infection control. The ID Now influenza A & B 2 (ID Now) assay (Abbott Laboratories), Cobas influenza A/B nucleic acid test (LIAT; Roche Molecular Systems, Inc.), and Xpert Xpress Flu (Xpert; Cepheid) are rapid, point-of-care molecular assays for Flu virus detection. The study aim was to compare the performances of these three commercially available Clinical Laboratory Improvement Amendments (CLIA)-waived Flu virus assays. We prospectively enrolled 201 children <18 years old from January to April 2018 and collected nasopharyngeal swab specimens in viral medium. Aliquots were frozen for testing on different diagnostic platforms, as per the manufacturers' instructions. CDC Flu A/B PCR was used as a reference method to evaluate the performances of these three platforms. Among the 201 specimens tested, the CDC Flu A/B PCR assay detected Flu A/B virus in 107 samples (Flu A virus, 73 samples; Flu B virus, 36 samples; dual Flu A/B virus positive, 2 samples), while the ID Now virus detected 102 samples (Flu A virus, 69 samples; Flu B virus, 37 samples; dual Flu A/B virus positive, 4 samples; invalid rate, 1/201 [0.5%]), the LIAT detected 112 samples (Flu A virus, 74 samples; Flu B virus, 38 samples; invalid rate, 11/201 [5.5%]), and the Xpert assay detected 112 samples (Flu A virus, 76 samples; Flu B virus, 36 samples; invalid rate, 6/201 [3.0%]). The overall sensitivities for the ID Now assay, LIAT, and Xpert assay for Flu A virus detection (93.2%, 100%, and 100%, respectively) and Flu B virus detection (97.2%, 94.4%, and 91.7%, respectively) were comparable. The specificity for Flu A and B virus detection by all methods was >97%. These molecular assays had higher sensitivity than did a historical standard-of-care test from the BD Veritor antigen test (Flu A virus, 79.5%; Flu B virus, 66.7%).

Public health principles to inform testing and build trust in automated vehicles.

Highly publicised crashes involving self-driving or autonomous vehicles (AVs) have raised questions about safety and eroded public trust in the technology. In this State of the Art Review, we draw on previous successes in injury prevention and public health to focus attention on three strategies to reduce risk and build public confidence as AVs are being tested on public roads. Data pooling, a graduated approach to risk exposure, and harm reduction principles each offer practical lessons for AV testing. The review points out how the eventual deployment of AV technology could have a substantial impact on public health. In this regard, inclusive testing, public education and smart policy could extend the social value of AVs by improving access to mobility and by directing deployments towards scenarios with the greatest population health impact. The application of these strategies does not imply slowing down progress; rather, their implementation could accelerate adoption and result in realising the benefits of AVs more quickly and comprehensively while minimising risks.

Drosophila IRBP bZIP heterodimer binds P-element DNA and affects hybrid dysgenesis.

In Drosophila, P-element transposition causes mutagenesis and genome instability during hybrid dysgenesis. The P-element 31-bp terminal inverted repeats (TIRs) contain sequences essential for transposase cleavage and have been implicated in DNA repair via protein-DNA interactions with cellular proteins. The identity and function of these cellular proteins were unknown. Biochemical characterization of proteins that bind the TIRs identified a heterodimeric basic leucine zipper (bZIP) complex between an uncharacterized protein that we termed "Inverted Repeat Binding Protein (IRBP) 18" and its partner Xrp1. The reconstituted IRBP18/Xrp1 heterodimer binds sequence-specifically to its dsDNA-binding site within the P-element TIRs. Genetic analyses implicate both proteins as critical for repair of DNA breaks following transposase cleavage in vivo. These results identify a cellular protein complex that binds an active mobile element and plays a more general role in maintaining genome stability.

A Novel Pediatric Emergency Department Intervention to Improve Adolescent Sexual Health Care.

OBJECTIVE: The aim of this study was to evaluate a novel educational intervention for physician trainees to improve sexual health care provision, including condom distribution, in the pediatric emergency department. METHODS: Resident physicians and medical students in an urban pediatric emergency department viewed an evidence-based educational video on sexual health care provision. It featured role-plays and a description of the condom distribution process, and targeted trainees who provide health care to patients aged 14 years or more with potential genitourinary complaints. Trainees completed pre- and postintervention surveys to assess attitudes, motivation, and confidence for 4 recommended practices (Likert scale, 1 = not at all to 4 = extremely). We used Wilcoxon signed rank tests to assess differences in paired responses to motivation and confidence statements. A subset of 33 trainees completed a brief survey to assess condom distribution during emergency department clinical encounters. RESULTS: Of 56 trainees, 51 (91%) participated: 53% female, 58% from pediatrics. At baseline, participants reported high levels of confidence and motivation to provide sexual health care. Postintervention, there were significant increases in the proportion of participants who reported greater motivation and confidence to (1) ask a parent to step out of the room, (2) obtain sexual history, (3) discuss condom use, and (4) offer condoms (all P < 0.05). Postintervention, fewer participants "agreed/strongly agreed" that there is inadequate time to obtain sexual histories (22% vs 45%; P < 0.05). Most (60%) sexually active patients accepted condoms during clinical care. CONCLUSION: In this pediatric emergency department, a low-cost intervention showed promise to improve trainee attitudes, motivation, and confidence toward adolescent sexual health care provision. These data may inform strategies to improve access to care for this population.

Evaluation of the illumigene Mycoplasma Direct DNA Amplification Assay.

Mycoplasma pneumoniae is a common cause of community-acquired pneumonia. The illumigene Mycoplasma Direct (iMD) DNA amplification assay is a qualitative in vitro test utilizing loop-mediated isothermal amplification (LAMP) technology for the direct detection of M. pneumoniae DNA in respiratory specimens. The iMD assay does not require the preextraction of nucleic acids from specimens, which is a prerequisite step for the previously approved illumigene Mycoplasma (iM) assay. The aim of this prospective multicenter study was to evaluate the performance characteristics of the newly developed iMD assay, compared with the iM assay. Subjects with symptoms of upper respiratory illnesses suggesting M. pneumoniae infection were enrolled at three sites in the United States. Respiratory specimens were obtained using dual throat swabs. One swab was tested with the iMD assay at each enrollment site. Reference testing with the iM assay was performed by the manufacturer. Among 456 specimens tested, the iM reference method detected M. pneumoniae in 25 specimens (5.5%), while the iMD assay identified 34 specimens (7.5%) as M. pneumoniae positive. There were 10 false-positive results and 1 false-negative result with the iMD assay. The overall positive and negative agreement rates were 96.0% (95% confidence interval [CI], 80.5 to 99.3%) and 97.7% (95% CI, 95.8 to 98.7%), respectively. The overall agreement rate was determined to be 97.6% (95% CI, 95.7 to 98.6%). We conclude that the iMD test results were comparable to the iM assay results. The removal of the DNA extraction step for the iMD assay simplifies testing, saves time, and reduces the costs of detecting M. pneumoniae from throat swabs, compared to the iM assay.

Determinants of VH1-46 Cross-Reactivity to Pemphigus Vulgaris Autoantigen Desmoglein 3 and Rotavirus Antigen VP6.

Shared VH1-46 gene usage has been described in B cells reacting to desmoglein 3 (Dsg3) in the autoimmune disease pemphigus vulgaris (PV), as well as B cells responding to rotavirus capsid protein VP6. In both diseases, VH1-46 B cells bearing few to no somatic mutations can recognize the disease Ag. This intriguing connection between an autoimmune response to self-antigen and an immune response to foreign Ag prompted us to investigate whether VH1-46 B cells may be predisposed to Dsg3-VP6 cross-reactivity. Focused testing of VH1-46 mAbs previously isolated from PV and rotavirus-exposed individuals indicates that cross-reactivity is rare, found in only one of seven VH1-46 IgG clonotypes. High-throughput screening of IgG B cell repertoires from two PV patients identified no additional cross-reactive clonotypes. Screening of IgM B cell repertoires from one non-PV and three PV patients identified specific cross-reactive Abs in one PV patient, but notably all six cross-reactive clonotypes used VH1-46. Site-directed mutagenesis studies indicate that amino acid residues predisposing VH1-46 Abs to Dsg3 reactivity reside in CDR2. However, somatic mutations only rarely promote Dsg3-VP6 cross-reactivity; most mutations abolish VP6 and/or Dsg3 reactivity. Nevertheless, functional testing identified two cross-reactive VH1-46 Abs that both disrupt keratinocyte adhesion and inhibit rotavirus replication, indicating the potential for VH1-46 Abs to have both pathologic autoimmune and protective immune functions. Taken together, these studies suggest that certain VH1-46 B cell populations may be predisposed to Dsg3-VP6 cross-reactivity, but multiple mechanisms prevent the onset of autoimmunity after rotavirus exposure.

Effect of an Asthma Guideline in 2 Pediatric Emergency Departments and an Urgent Care Center.

OBJECTIVES: The objective of this study was to evaluate ordering of albuterol via metered-dose inhaler with spacer (MDI-spacer), length of stay (LOS), and 72-hour return rates before and after publication of an internally developed pediatric asthma clinical practice guideline (CPG). METHODS: The internally developed CPG reflected national recommendations. It was explained at faculty meetings by a respected clinician and published on the intranet on February 6, 2012. We performed a retrospective study of visits from January 1, 2009, to October 31, 2014, by children aged 2 to 17 years with a primary diagnosis of asthma and discharged from a target site (2 pediatric emergency departments and 1 urgent care center). We excluded critical/emergent visits and those by patients who transferred to the emergency department/urgent care center from another facility or were admitted. We extracted data for 37 months before and 33 months after CPG implementation (post-CPG) using a single electronic health record system. RESULTS: Albuterol delivery via MDI-spacer increased by 33.95% (P < 0.0001) during 1-month post-CPG implementation with no significant subsequent decrease. An unexpected decline was noted for median LOS before CPG implementation (-1.24 minutes; P < 0.0001). For MDI-spacer-treated patients post-CPG, decreased median LOS was maintained and there was decreased variability of the median LOS (P < 0.001). For nebulizer-treated patients post-CPG, median LOS increased (.95 minutes; P = 0.033). No change was observed for 72-hour return rates. CONCLUSIONS: Implementation of an asthma CPG increased ordering of albuterol via MDI-spacer. The increase was sustained over time in all study sites. Decreased variability in median LOS for MDI-spacer patients was observed post-CPG. Median LOS for those treated with MDI-spacer exclusively remained unchanged in the post-CPG period, whereas post-CPG LOS increased in those who received nebulized albuterol.

The dual nature of interleukin-10 in pemphigus vulgaris.

The immunomodulatory cytokine interleukin-10 (IL-10) plays beneficial but also potentially detrimental roles in inflammation, infection, and autoimmunity. Recent studies suggest a regulatory role for IL-10-expressing B cells in the autoimmune blistering disease pemphigus vulgaris. Here we review the studies on IL-10 in pemphigus vulgaris and discuss the potential pathophysiological significance of these findings in comparison to prior studies of IL-10 in other human conditions. A better understanding of the complex roles of IL-10 in immune regulation may improve our understanding of pemphigus pathogenesis and treatment.

Prevalence and Use of Driver Monitoring Systems: A National Survey in the United States.

The purpose of this study was to measure the prevalence of use of driver monitoring systems among U.S. adults, and factors influencing their adoption. One in five U.S. adults has used driver monitoring, primarily to obtain a discount on insurance. Safety benefits and financial incentives are likely to influence adoption.

Awake at the wheel: how auto technology innovations present ongoing sleep challenges and new safety opportunities.

Individuals and society are dependent on transportation. Individuals move about their world for work, school, healthcare, social activities, religious and athletic events, and so much more. Society requires the movement of goods, food, medicine, etc. for basic needs, commerce, cultural and political exchanges, and all of its dynamic, complex elements. To meet these critical daily demands, the transportation system operates globally and around the clock. Regardless of their role, a basic requirement for the individuals operating the transportation system is that they are awake and at optimal alertness. This applies to individuals driving their own cars, riding a bike or motorcycle, as well as pilots of commercial aircraft, train engineers, long-haul truck drivers, and air traffic controllers. Alert operators are a basic requirement for a safe and effective transportation system. Decades of scientific and operational research have demonstrated that the 24/7 scheduling demands on operators and passengers of our transportation system create sleep and circadian disruptions that reduce alertness and performance and cause serious safety problems. These challenges underly the longstanding interest in transportation safety by the sleep and circadian scientific community. An area currently offering perhaps the most significant opportunities and challenges in transportation safety involves vehicle technology innovations. This paper provides an overview of these latest innovations with a focus on sleep-relevant issues and opportunities. Drowsy driving is discussed, along with fatigue management in round-the-clock transportation operations. Examples of cases where technology innovations could improve or complicate sleep issues are discussed, and ongoing sleep challenges and new safety opportunities are considered.

Advancing Transportation Equity and Safety Through Autonomous Vehicles.

Motor vehicle crashes are a leading cause of death in the United States, and disproportionately impact communities of color. Replacing human control with automated vehicles (AVs) holds the potential to reduce crashes and save lives. The benefits of AVs, including automated shuttles, buses, or cars could extend beyond safety to include improvements in congestion, reductions in emissions, and increased access to mobility, particularly for vulnerable populations. However, AVs have not attained the level of public trust that has been expected, given their potential to save lives and increase access to mobility. Public opinion surveys have highlighted safety and security concerns as reasons for this lack of confidence. In this study, we present the findings of an experiment we conducted to actively shift mindsets on AVs toward advancing health equity. We demonstrate through a nationally representative sample of 2265 U.S. adults that the public support for AVs can be improved by expanding their scope of application to include advancing social benefit. The survey began with questions on respondent's support for AVs based on a priori knowledge and beliefs. Consistent with prior surveys, baseline support (strong support and some degree of support) was low at 26.4% (95% confidence interval 24.0-29.0). After introducing information about how AVs could be used to provide mobility for older adults, those with limited income, or the vision-impaired, respondents were asked to reassess their support for AVs. Support significantly increased to include the majority of respondents. By prioritizing the deployment of AVs to serve individuals and communities in greatest need of mobility, AVs would not only demonstrate compelling social value by reducing disparities but would also gain widespread public support among the U.S. public.

Point-of-care ultrasound to inform antiviral treatment initiation in chronic hepatitis B virus infection in low-resource settings - the PUSH protocol.

BACKGROUND: Chronic Hepatitis B (CHB) is prevalent worldwide and most related deaths occur in low-resource settings. Antiviral treatment of CHB is indicated in those with significant liver disease and markers of viral replication. However, recommended diagnostics such as elastography (a non-invasive imaging measure of fibrosis/cirrhosis) or HBV viral load are often lacking in these settings, which creates barriers to treatment. Point-of-care clinical B-mode ultrasound (US) has potential to overcome implementation barriers in HBV care programs in low-resource settings. METHODS: We describe a Point-of-care US protocol for Hepatitis ("PUSH") to check for signs of cirrhosis and hepatocellular carcinoma in the liver of people with CHB. We performed a prospective observational study applying the protocol, first by trainee clinicians and then by trainers, in consecutive patients referred to our clinic for CHB treatment eligibility assessment. All patients additionally underwent physical examination, liver function tests (LFTs) and platelet counts. We describe the PUSH training approach and performance of the protocol. RESULTS: Four clinicians and 111 adult patients with HBV infection were included in the development of PUSH. Using US, liver complications of HBV were documented in 31 (27.9%) patients; including cirrhosis in 15 patients, HCC with cirrhosis in 13, and HCC without cirrhosis in 3. Patients with sonographic findings had significantly more clinical symptoms also their LFTs were higher and more frequently indicative for HBV treatment. Of 28 patients with sonographic diagnosis of cirrhosis, 23 (82.1%) showed a nodular liver surface, 24 (85.7%) a coarse echotexture, 20 (71.4%) scarce vessels, and 9 (32.1%) an enlarged caudate lobe. Overall concordance of the findings between assessment of trainees and experienced sonographers was high, ranging from 90 to 95%; trainees were not blinded to clinical and laboratory findings. CONCLUSION: Ultrasound can facilitate same-day initiation of antiviral therapy for chronic HBV monoinfection in a resource-limited setting and a streamlined protocol-driven liver ultrasound can be feasibly used by front line clinicians managing HBV.

Dbf4 is direct downstream target of ataxia telangiectasia mutated (ATM) and ataxia telangiectasia and Rad3-related (ATR) protein to regulate intra-S-phase checkpoint.

Dbf4/Cdc7 (Dbf4-dependent kinase (DDK)) is activated at the onset of S-phase, and its kinase activity is required for DNA replication initiation from each origin. We showed that DDK is an important target for the S-phase checkpoint in mammalian cells to suppress replication initiation and to protect replication forks. We demonstrated that ataxia telangiectasia mutated (ATM) and ataxia telangiectasia and Rad3-related (ATR) proteins directly phosphorylate Dbf4 in response to ionizing radiation and replication stress. We identified novel ATM/ATR phosphorylation sites on Dbf4 and showed that ATM/ATR-mediated phosphorylation of Dbf4 is critical for the intra-S-phase checkpoint to inhibit DNA replication. The kinase activity of DDK, which is not suppressed upon DNA damage, is required for fork protection under replication stress. We further demonstrated that ATM/ATR-mediated phosphorylation of Dbf4 is important for preventing DNA rereplication upon loss of replication licensing through the activation of the S-phase checkpoint. These studies indicate that DDK is a direct substrate of ATM and ATR to mediate the intra-S-phase checkpoint in mammalian cells.