Performance limitations of resonant refractive index sensors with low-cost components

Resonant biosensors are attractive for diagnostics because they can detect clinically relevant biomarkers with high sensitivity and in a label-free fashion. Most of the current solutions determine their detection limits in a highly stabilised laboratory environment, which does, however, not apply to real point-of-care applications. Here, we consider the more realistic scenario of low-cost components and an unstabilised environment and consider the related design implications. We find that sensors with lower quality-factor resonances are more fault tolerant, that a filtered LED lightsource is advantageous compared to a diode laser, and that a CMOS camera is preferable to a CCD camera for detection. We exemplify these findings with a guided mode resonance sensor and experimentally determine a limit of detection of 5.8 ± 1.7×10−5 refractive index units (RIU), which is backed up by a model identifying the various noise sources. Our findings will inform the design of high performance, low cost biosensors capable of operating in a real-world environment

PHarmacist Avoidance or Reductions in Medical Costs in CRITically Ill Adults: PHARM-CRIT Study

OBJECTIVES: To comprehensively classify interventions performed by ICU clinical pharmacists and quantify cost avoidance generated through their accepted interventions. DESIGN: A multicenter, prospective, observational study was performed between August 2018 and January 2019. SETTING: Community hospitals and academic medical centers in the United States. PARTICIPANTS: ICU clinical pharmacists. INTERVENTIONS: Recommendations classified into one of 38 intervention categories (divided into six unique sections) associated with cost avoidance. MEASUREMENTS AND MAIN RESULTS: Two-hundred fifteen ICU pharmacists at 85 centers performed 55,926 interventions during 3,148 shifts that were accepted on 27,681 adult patient days and generated $23,404,089 of cost avoidance. The quantity of accepted interventions and cost avoidance generated in six established sections was adverse drug event prevention (5,777 interventions;$5,822,539 CA), resource utilization (12,630 interventions; $4,491,318), individualization of patient care (29,284 interventions;$9,680,036 cost avoidance), prophylaxis (1,639 interventions; $1,414,465 cost avoidance), hands-on care (1,828 interventions;$1,339,621 cost avoidance), and administrative/supportive tasks (4,768 interventions; $656,110 cost avoidance). Mean cost avoidance was$418 per intervention, $845 per patient day, and$7,435 per ICU pharmacist shift. The annualized cost avoidance from an ICU pharmacist is $1,784,302. The potential monetary cost avoidance to pharmacist salary ratio was between$3.3:1 and $9.6:1. CONCLUSIONS: Pharmacist involvement in the care of critically ill patients results in significant avoidance of healthcare costs, particularly in the areas of individualization of patient care, adverse drug event prevention, and resource utilization. The potential monetary cost avoidance to pharmacist salary ratio employing an ICU clinical pharmacist is between$3.3:1 and $9.6:1

Extended Kalman Filtering Projection Method to Reduce the 3σ Noise Value of Optical Biosensors

Optical biosensors have experienced a rapid growth over the past decade because of their high sensitivity and the fact that they are label-free. Many optical biosensors rely on tracking the change in a resonance signal or an interference pattern caused by the change in refractive index that occurs upon binding to a target biomarker. The most commonly used method for tracking such a signal is based on fitting the data with an appropriate mathematical function, such as a harmonic function or a Fano, Gaussian, or Lorentz function. However, these functions have limited fitting efficiency because of the deformation of data from noise. Here, we introduce an extended Kalman filter projection (EKFP) method to address the problem of resonance tracking and demonstrate that it improves the tolerance to noise, reduces the 3σ noise value, and lowers the limit of detection (LOD). We utilize the method to process the data of experiments for detecting the binding of C-reactive protein in a urine matrix with a chirped guided mode resonance sensor and are able to improve the LOD from 10 to 1 pg/mL. Our method reduces the 3σ noise value of this measurement compared to a simple Fano fit from 1.303 to 0.015 pixels. These results demonstrate the significant advantage of the EKFP method to resolving noisy data of optical biosensors

Vancomycin Dosing Practices among Critical Care Pharmacists: A Survey of Society of Critical Care Medicine Pharmacists

Introduction: Critically ill patients and their pharmacokinetics present complexities often not considered by consensus guidelines from the American Society of Health-System Pharmacists, the Infectious Diseases Society of America, and the Society of Infectious Diseases Pharmacists. Prior surveys have suggested discordance between certain guideline recommendations and reported infectious disease pharmacist practice. Vancomycin dosing practices, including institutional considerations, have not previously been well described in the critically ill patient population. Objectives: To evaluate critical care pharmacists\u27 self-reported vancomycin practices in comparison to the 2009 guideline recommendations and other best practices identified by the study investigators. Methods: An online survey developed by the Research and Scholarship Committee of the Clinical Pharmacy and Pharmacology (CPP) Section of the Society of Critical Care Medicine (SCCM) was sent to pharmacist members of the SCCM CPP Section practicing in adult intensive care units in the spring of 2017. This survey queried pharmacists\u27 self-reported practices regarding vancomycin dosing and monitoring in critically ill adults. Results: Three-hundred and sixty-four responses were received for an estimated response rate of 26%. Critical care pharmacists self-reported largely following the 2009 vancomycin dosing and monitoring guidelines. The largest deviations in guideline recommendation compliance involve consistent use of a loading dose, dosing weight in obese patients, and quality improvement efforts related to systematically monitoring vancomycin-associated nephrotoxicity. Variation exists regarding pharmacist protocols and other practices of vancomycin use in critically ill patients. Conclusion: Among critical care pharmacists, reported vancomycin practices are largely consistent with the 2009 guideline recommendations. Variations in vancomycin dosing and monitoring protocols are identified, and rationale for guideline non-adherence with loading doses elucidated

PHarmacist Avoidance or Reductions in Medical Costs in Patients Presenting the EMergency Department: PHARM-EM Study

Objectives: To comprehensively classify interventions performed by emergency medicine clinical pharmacists and quantify cost avoidance generated through their accepted interventions. Design: A multicenter, prospective, observational study was performed between August 2018 and January 2019. Setting: Community and academic hospitals in the United States. Participants: Emergency medicine clinical pharmacists. Interventions: Recommendations classified into one of 38 intervention categories associated with cost avoidance. Measurements and Main Results: Eighty-eight emergency medicine pharmacists at 49 centers performed 13,984 interventions during 917 shifts that were accepted on 8,602 patients and generated $7,531,862 of cost avoidance. The quantity of accepted interventions and cost avoidance generated in six established categories were as follows: adverse drug event prevention (1,631 interventions;$2,225,049 cost avoidance), resource utilization (628; $310,582), individualization of patient care (6,122;$1,787,170), prophylaxis (24; $22,804), hands-on care (3,533;$2,836,811), and administrative/supportive tasks (2,046; $342,881). Mean cost avoidance was$538.61 per intervention, $875.60 per patient, and$8,213.59 per emergency medicine pharmacist shift. The annualized cost avoidance from an emergency medicine pharmacist was $1,971,262. The monetary cost avoidance to pharmacist salary ratio was between$1.4:1 and $10.6:1. Conclusions: Pharmacist involvement in the care of patients presenting to the emergency department results in significant avoidance of healthcare costs, particularly in the areas of hands-on care and adverse drug event prevention. The potential monetary benefit-to-cost ratio for emergency medicine pharmacists is between$1.4:1 and $10.6:1

Phenotypic covariance structure and its divergence for acoustic mate attraction signals among four cricket species

The phenotypic variance–covariance matrix (P) describes the multivariate distribution of a population in phenotypic space, providing direct insight into the appropriateness of measured traits within the context of multicollinearity (i.e., do they describe any significant variance that is independent of other traits), and whether trait covariances restrict the combinations of phenotypes available to selection. Given the importance of P, it is therefore surprising that phenotypic covariances are seldom jointly analyzed and that the dimensionality of P has rarely been investigated in a rigorous statistical framework. Here, we used a repeated measures approach to quantify P separately for populations of four cricket species using seven acoustic signaling traits thought to enhance mate attraction. P was of full or almost full dimensionality in all four species, indicating that all traits conveyed some information that was independent of the other traits, and that phenotypic trait covariances do not constrain the combinations of signaling traits available to selection. P also differed significantly among species, although the dominant axis of phenotypic variation (pmax) was largely shared among three of the species (Acheta domesticus, Gryllus assimilis, G. texensis), but different in the fourth (G. veletis). In G. veletis and A. domesticus, but not G. assimilis and G. texensis, pmax was correlated with body size, while pmax was not correlated with residual mass (a condition measure) in any of the species. This study reveals the importance of jointly analyzing phenotypic traits

Association of T-Zone Reticular Networks and Conduits with Ectopic Lymphoid Tissues in Mice and Humans

Ectopic or tertiary lymphoid tissues (TLTs) are often induced at sites of chronic inflammation. They typically contain various hematopoietic cell types, high endothelial venules, and follicular dendritic cells; and are organized in lymph node–like structures. Although fibroblastic stromal cells may play a role in TLT induction and persistence, they have remained poorly defined. Herein, we report that TLTs arising during inflammation in mice and humans in a variety of tissues (eg, pancreas, kidney, liver, and salivary gland) contain stromal cell networks consisting of podoplanin+ T-zone fibroblastic reticular cells (TRCs), distinct from follicular dendritic cells. Similar to lymph nodes, TRCs were present throughout T-cell–rich areas and had dendritic cells associated with them. They expressed lymphotoxin (LT) β receptor (LTβR), produced CCL21, and formed a functional conduit system. In rat insulin promoter–CXCL13–transgenic pancreas, the maintenance of TRC networks and conduits was partially dependent on LTβR and on lymphoid tissue inducer cells expressing LTβR ligands. In conclusion, TRCs and conduits are hallmarks of secondary lymphoid organs and of well-developed TLTs, in both mice and humans, and are likely to act as important scaffold and organizer cells of the T-cell–rich zone

Autonomous photonic biosensor

Early diagnosis and targeted disease treatment are essential elements of healthcare provision. Current systems often revolve around symptomatic diagnosis and laboratory testing when needed. These systems often result in semi-blind treatment or long wait times. Point-of-care biosensors that can quantify specific biomarkers have an important role to play in this context as they bridge the gap of quick and specific testing in healthcare provision. Photonic biosensors have been demonstrated as a laboratory diagnostic tool with well-established advantages, achieving low limits of detections for protein biomarkers. Several issues remain before they can be translated into commonly used point-of-care instruments. Ideally, integrated photonic biosensors should be inexpensive, sensitive and easy to use. However, many existing photonic biosensors require complex readout equipment, such as external spectrometers, or precise and bulky optical coupling. Presented in this thesis is the development of a low-cost photonic biosensing instrument. The modality used is that of a chirped one-dimensional guided mode resonance sensor. When used in conjunction with a monochromatic source, detection can be accomplished simply by a camera in a compact microscope-style configuration. A study into the performance of low-cost components was conducted to understand the sources of noise. With the understanding gained from this study the instrument was able to achieve a bulk refractive index sensitivity of 3.1 ±0.6 ×10-5 Refractive Index Units. This limit of detection is comparable to other laboratory based modalities and so the device was tested with C-Reactive Protein and Immunoglobulin G assays as example proteins. The best performance achieved was detection of 1 ng/mL for C Reactive Protein, well below the clinically relevant range. The limits of detection achieved using low-cost components indicates that photonic biosensors are well suited to clinical situations and have the potential to play a significant role in the development of diagnostics in the future for healthcare