Publications by authors named "Ravi Chawla"

The inorganic biopolymer polyphosphate (polyP) occurs in all domains of life and affects myriad cellular processes. A longstanding observation is polyP's frequent proximity to chromatin, and, in many bacteria, its occurrence as magnesium (Mg)-enriched condensates embedded in the nucleoid region, particularly in response to stress. The physical basis of the interaction between polyP, DNA and Mg, and the resulting effects on the organization of the nucleoid and polyP condensates, remain poorly understood.

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The ancient, inorganic biopolymer polyphosphate (polyP) occurs in all three domains of life and affects myriad cellular processes. An intriguing feature of polyP is its frequent proximity to chromatin, and in the case of many bacteria, its occurrence in the form of magnesium-enriched condensates embedded in the nucleoid, particularly in response to stress. The physical basis of the interaction between polyP and DNA, two fundamental anionic biopolymers, and the resulting effects on the organization of both the nucleoid and polyP condensates remain poorly understood.

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Indole is a major component of the bacterial exometabolome, and the mechanisms for its wide-ranging effects on bacterial physiology are biomedically significant, although they remain poorly understood. Here, we determined how indole modulates the functions of a widely conserved motility apparatus, the bacterial flagellum. Our experiments in revealed that indole influences the rotation rates and reversals in the flagellum's direction of rotation via multiple mechanisms.

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Synthesis of polyphosphate (polyP) is an ancient and universal stress and starvation response in bacteria. In many bacteria, polyP chains come together to form granular superstructures within cells. Some species appear to regulate polyP granule subcellular organization.

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As the use of machine learning algorithms in health care continues to expand, there are growing concerns about equity, fairness, and bias in the ways in which machine learning models are developed and used in clinical and business decisions. We present a guide to the data ecosystem used by health insurers to highlight where bias can arise along machine learning pipelines. We suggest mechanisms for identifying and dealing with bias and discuss challenges and opportunities to increase fairness through analytics in the health insurance industry.

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Fluorescent proteins that modulate their emission intensities when protonated serve as excellent probes of the cytosolic pH. Since the total fluorescence output fluctuates significantly due to variations in the fluorophore levels in cells, eliminating the dependence of the signal on protein concentration is crucial. This is typically accomplished with the aid of ratiometric fluorescent proteins such as pHluorin.

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Bacterial chemotaxis to prominent microbiota metabolites such as indole is important in the formation of microbial communities in the gastrointestinal (GI) tract. However, the basis of chemotaxis to indole is poorly understood. Here, we exposed to a range of indole concentrations and measured the dynamic responses of individual flagellar motors to determine the chemotaxis response.

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There is growing interest in using predictive analytics to drive interventions that reduce avoidable healthcare utilization. This study evaluates the impact of such an intervention utilizing claims from 2013 to 2017 for high-risk Medicare Advantage patients with congestive heart failure. A predictive algorithm using clinical and nonclinical information produced a risk score ranking for health plan members in 10 separate waves between July 2013 and May 2015.

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The attractant chemotaxis response of Escherichia coli to norepinephrine requires that it be converted to 3,4-dihydroxymandelic acid (DHMA) by the monoamine oxidase TynA and the aromatic aldehyde dehydrogenase FeaB. DHMA is sensed by the serine chemoreceptor Tsr, and the attractant response requires that at least one subunit of the periplasmic domain of the Tsr homodimer (pTsr) has an intact serine-binding site. DHMA that is generated in vivo by E.

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Surface sensing in bacteria is a precursor to the colonization of biotic and abiotic surfaces, and an important cause of drug resistance and virulence. As a motile bacterium approaches and adheres to a surface from the bulk fluid, the mechanical forces that act on it change. Bacteria are able to sense these changes in the mechanical load through a process termed mechanosensing.

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Accreditation of providers helps resolve the pervasive information asymmetries in health care markets. However, meeting accreditation standards typically involves flexibility in implementation, leading to heterogeneity in performance. For example, the patient-centered medical home (PCMH) is a leading model for recognizing high-performing primary care practices.

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Bacillus subtilis flagella are not only required for locomotion but also act as sensors that monitor environmental changes. Although how the signal transmission takes place is poorly understood, it has been shown that flagella play an important role in surface sensing by transmitting a mechanical signal to control the DegS-DegU two-component system. Here we report a role for flagella in the regulation of the K-state, which enables transformability and antibiotic tolerance (persistence).

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The stator-complex in the bacterial flagellar motor is responsible for surface-sensing. It remodels in response to perturbations in viscous loads, recruiting additional stator-units as the load increases. Here, we tested a hypothesis that the amount of torque generated by each stator-unit modulates its association with the rotor.

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Article Synopsis
  • Flagellar motors in bacteria are crucial for movement and responding to their environment, which can influence their ability to colonize surfaces and cause infections.
  • Recent research shows that these motors can change their structure and functions based on different environmental cues.
  • A new method using photomultiplier-based bead tracking allows scientists to monitor the motors' behaviors in real-time, providing insights into their speed and switching characteristics across different bacteria.
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Objective: To assess whether adoption of the patient-centered medical home (PCMH) reduces emergency department (ED) utilization among patients with and without chronic illness.

Data Sources: Data from approximately 460,000 Independence Blue Cross patients enrolled in 280 primary care practices, all converting to PCMH status between 2008 and 2012.

Research Design: We estimate the effect of a practice becoming PCMH-certified on ED visits and costs using a difference-in-differences approach which exploits variation in the timing of PCMH certification, employing either practice or patient fixed effects.

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Objectives: Evaluate the effects of the patient-centered medical home (PCMH) model on medical costs and utilization in the nonpediatric population, particularly among high-risk patients.

Study Design: Longitudinal case-control design, comparing per member per month (PMPM) cost and utilization per 1000 patients for members enrolled in PCMH and non-PCMH practices from 2009 to 2011.

Methods: Commercial health maintenance organization members in nonpediatric practices that adopted the PCMH model in 2009 were matched to patients in nonpediatric practices that did not adopt the model until 2011 or later.

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Objective: To compare costs and utilization for patients with diabetes enrolled in patient-centered medical home (PCMH) practices and non-PCMH practices.

Design: Commercial Health Maintenance Organization members with diabetes who enrolled between 2008 and 2011 in 26 Pennsylvania-based PCMH practices that were recognized by the National Committee for Quality Assurance in 2009 were compared with similar patients in 97 non-PCMH primary care practices. A difference-in-differences longitudinal research design was used to analyze differences between both groups on per-member, per-month costs and utilization.

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