Tuning the resonance frequencies and mode shapes in a large range multi-degree of freedom micromirror.

The ability to actively shift the primary resonance of a 2D scanning micromirror allows the user to set the scanning direction, set the scanning frequency, and lift otherwise degenerate modes in a symmetrically designed system. In most cases, resonant scanning micromirrors require frequency stability in order to perform imaging and projection functions properly. This paper suggests a method to tune the tip and tilt resonant frequencies in real time while actively suppressing or allowing degeneracy of the two modes in a symmetric electrothermal micromirror. We show resonant frequency tuning with a range of degeneracy separation of 470 Hz or by approximately ±15% and controllable coupling.

Beam shaping with tip-tilt varifocal mirror for indoor optical wireless communication.

MEMS mirrors are currently used in many applications to steer beams of light. An area of continued research is developing mirrors with varifocal capability that allows the beam to be shaped and focused. In this work, we study the varifocal capability of a 380 µm diameter, thermally actuated MEMS mirror with a ± 40° tip-tilt angle and a radius of curvature between -0.48 mm to 20.5 mm. Light is coupled to the mirror via a single mode optical fiber, similar to an indoor optical wireless communication architecture. The performance of the mirror is characterized with respect to (1) the profile of the reflected beam as the mirror deforms and (2) the mirror's impact when integrated into an optical communication system. We found that the mirror can focus light to a beam with a 0.18° half-angle divergence. Additionally, the ability to change the shape of fiberized light from a wide to narrow beam provides an unmatched level of dynamic control and significantly improves the bit error rate in an optical communication system.

Growth and physiology of Clostridium perfringens wild-type and ΔazoC knockout: an azo dye exposure study.

Clostridium perfringens, a strictly anaerobic micro-organism and inhabitant of the human intestine, has been shown to produce the azoreductase enzyme AzoC, an NAD(P)H-dependent flavin oxidoreductase. This enzyme reduces azo dyes to aromatic amines, which are carcinogenic in nature. A significant amount of work has been completed that focuses on the activity of this enzyme; however, few studies have been completed that focus on the physiology of azo dye reduction. Dye reduction studies coupled with C. perfringens growth studies in the presence of ten different azo dyes and in media of varying complexities were completed to compare the growth rates and dye-reducing activity of C. perfringens WT cells, a C. perfringens ΔazoC knockout, and Bifidobacterium infantis, a non-azoreductase-producing control bacterium. The presence of azo dyes significantly increased the generation time of C. perfringens in rich medium, an effect that was not seen in minimal medium. In addition, azo dye reduction studies with the ΔazoC knockout suggested the presence of additional functional azoreductases in this medically important bacterium. Overall, this study addresses a major gap in the literature by providing the first look, to our knowledge, at the complex physiology of C. perfringens upon azo dye exposure and the effect that both azo dyes and the azoreductase enzyme have on growth.

Reducing Preventable Hospitalizations With Two Models of Transitional Care.

PURPOSE: Transitional care is an emerging model of health care designed to decrease preventable adverse events and associated utilization of health care through temporary follow-up after hospital discharge. This study describes the approaches and outcomes of two distinct transitional care programs serving different populations: one is provided by master's-prepared clinical nurse specialists (CNS) with a chronic disease self-management focus, another by physicians specializing in palliative care (PPCs). Existing research has shown that transitional care programs with intensive follow-up reduce hospitalizations, emergency department (ED) visits, and costs. Few studies, however, have included side-by-side descriptions of the efficacy of transitional care programs varying by healthcare providers or program focus. DESIGN: This is a retrospective cohort study comparing the number of ED visits and hospitalizations in the 120 days before and after the intervention for patients enrolled in each transitional care program. Each program included post-hospitalization home visits, but included differences in program focus (chronic disease vs. palliative), assessment and interventions, and population (rural vs. urban). Data from participants in the CNS program (September 2014 to December 2014) were analyzed (n = 98). The average age of participants was 69 years and 65% were female. Data were collected from patients from the PPC program from September 2014 to April 2015 (n = 71). Thirty participants died within 120 days after the intervention and were excluded; the remaining 41 were included in the analysis. Participants had an average age of 81 years and 63% were female. METHODS: For the CNS program, a secondary analysis of existing data was performed. For the PPC program, a review of patient charts was done to collect data on encounters. A Wilcoxon matched-pairs signed-rank test was performed to test for significance. FINDINGS: Patients in the CNS intervention had significantly fewer ED visits (p < .005) and hospitalizations (p < .005) in the 4 months after the intervention than in the 4 months before the intervention. Patients in the PPC program had a nonsignificant reduction in ED visits (p = .327) and a significant reduction in hospitalizations postintervention (p = .03). CONCLUSIONS: Both transitional programs have value in decreasing rehospitalizations. The CNS intervention also significantly reduced ED visits for their target population. Further study with randomized controlled trials is needed to allow for a better understanding of the healthcare workforce best fitted to enhance transitional care outcomes. Future study to examine the cost savings of each of the interventions is also needed. CLINICAL RELEVANCE: Transitional care programs have the potential to prevent unnecessary utilization of health care at the critical periods of transition that leave patients vulnerable to adverse events and poor outcomes.

Nursing Leadership in ACO Payment Reform.

Accountable Care Organizations (ACOs) are a promising new model for payment reform in the complex and fragmented health care system in the United States. Nursing vision and leadership are essential for the success of an organization participating in an ACO. By understanding the political, financial, and cultural facilitators and barriers to change, as well as models for helping organizations transition toward change (e.g., Kotter Model of Change Management), nurses have the potential to be leaders in health care change.

Electrothermally actuated tip-tilt-piston micromirror with integrated varifocal capability.

MEMS micromirrors have proven to be very important optical devices with applications ranging from steerable mirrors for switches and cross-connects to spatial light modulators for correcting optical distortions. Usually beam steering and focusing are done with different MEMS devices and tilt angles in excess of 10 degrees are seldom obtained. Here we describe a single MEMS device that combines tip/tilt, piston mode and varifocal capability into a single, low cost device with very large tilt angles. Our device consists of a 400 micron diameter mirror driven with thermal bimorphs. We have demonstrated deflection angles of ± 40 degrees along both axes, a tunable focal length which varies between -0.48 mm to + 20.5 mm and a piston mode range of 300 microns - four separately controllable degrees of freedom in a single device. Potential applications range from smart lighting to optical switches and devices for telecom systems.

Non-classical azoreductase secretion in Clostridium perfringens in response to sulfonated azo dye exposure.

Clostridium perfringens, a strictly anaerobic microorganism and inhabitant of the human intestine, has been shown to produce an azoreductase enzyme (AzoC), an NADH-dependent flavin oxidoreductase. This enzyme reduces azo dyes into aromatic amines, which can be carcinogenic. A significant amount of work has been completed on the activity of AzoC. Despite this, much is still unknown, including whether azoreduction of these dyes occurs intracellularly or extracellulary. A physiological study of C. perfringens involving the effect of azo dye exposure was completed to answer this question. Through exposure studies, azo dyes were found to cause cytoplasmic protein release, including AzoC, from C. perfringens in dividing and non-dividing cells. Sulfonation (negative charge) of azo dyes proved to be the key to facilitating protein release of AzoC and was found to be azo-dye-concentration-dependent. Additionally, AzoC was found to localize to the Gram-positive periplasmic region. Using a ΔazoC knockout mutant, the presence of additional azoreductases in C. perfringens was suggested. These results support the notion that the azoreduction of these dyes may occur extracellularly for the commensal C. perfringens in the intestine.

Deletion of PTEN produces deficits in conditioned fear and increases fragile X mental retardation protein.

The phosphatase and tensin homolog detected on chromosome 10 (PTEN) gene product modulates activation of the phosphatidylinositol 3-kinase (PI3K)/AKT pathway. The PI3K pathway has been found to be involved in the regulation of the fragile X mental retardation protein, which is important for long-term depression and in the formation of new memories. We used delayed fear conditioning and trace fear conditioning to determine learning and memory deficits in neuron subset-specific Pten (NS-Pten) conditional knockout (KO) mice. We found that NS-Pten KO mice had deficits in contextual learning and trace conditioning, but did not have deficits in the ability to learn a conditioned stimulus. Furthermore, we found increased levels in the total and phosphorylated forms of the fragile X mental retardation protein (FMRP) in the hippocampus of NS-Pten KO mice.

A high-throughput small volume matrix based calibration using isotope dilution liquid chromatography tandem mass spectrometry analysis for 42 per and polyfluoroalkyl substances in groundwater.

A novel method for the determination of per- and polyfluoroalkyl substances (PFAS) in groundwater is presented using a subsample, matrix-matched calibrators, 96-well plate solid phase extraction (SPE), and ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). Accuracy, precision, measurement of uncertainty (MOU), method detection limit (MDL), method quantitation limit (MQL), analytical measurement range, interferences/ion suppression, and analyte stability were determined as part of the in-house method validation. The method quantitates 42 PFAS compounds from nine different compound classes. Accuracy for the reference material (RM) and matrix spike (MS) ranged from 52.3 to 117.8 %, and precision for the MS and matrix spike duplicate (MSD) had a coefficient of variation (CV) from 2.0 % to 23.3 %. MDLs spanned from 0.07 to 1.97 ng L-1, with MQLs ranging from 0.20 to 5.90 ng L-1. Suppression studies determined that iron and manganese have effects on analytes that do not have paired isotopically labeled standards. The results from the in-house validation indicated that this Michigan Department of Health and Human Services laboratory developed test meets the necessary accuracy, precision, MDL, MQL and reporting limits requirement established by the laboratory's quality system essentials (QSEs) and select criteria from the Department of Defense (DoD) Quality Systems Manual for Environmental Laboratories and American Industrial Hygiene Association Laboratory Accreditation Program, LLC (AIHA LAP, LLC) accrediting International Standard Organization (ISO/IEC 17025:2017) check list.

The non-enzymatic reduction of azo dyes by flavin and nicotinamide cofactors under varying conditions.

Azo dyes are ubiquitous in products and often become environmental pollutants due to their anthropogenic nature. Azoreductases are enzymes which are present within many bacteria and are capable of breaking down the azo dyes via reduction of the azo bond. Often, though, carcinogenic aromatic amines are formed as metabolites and are of concern to humans. Azoreductases function via an oxidation-reduction reaction and require cofactors (a nicotinamide cofactor and sometimes a flavin cofactor) to perform their function. Non-enzymatic reduction of azo dyes in the absence of an azoreductase enzyme has been suggested in previous studies, but has never been studied in detail in terms of varying cofactor combinations, different oxygen states or pHs, nor has the enzymatic reduction been compared to azoreduction in terms of dye reduction or metabolites produced, which was the aim of this study. Reduction of azo dyes by different cofactor combinations was found to occur under both aerobic and anaerobic conditions and under physiologically-relevant pHs to produce the same metabolites as an azoreductase. Our results show that, in some cases, the non-enzymatic reduction by the cofactors was found to be equal to that seen with the azoreductase, suggesting that all dye reduction in these cases is due to the cofactors themselves. This study details the importance of the use of a cofactor-only control when studying azoreductase enzymes.

Four-film X-ray series is more sensitive than 2-film for diagnosis of skull fractures in children.

OBJECTIVE: The objective of this study was to compare the sensitivity and specificity of 2- and 4-film x-ray series when interpreted by pediatric emergency medicine physicians in the diagnosis of skull fracture in children. METHODS: A noninferiority crossover study was performed. The skull radiographs of the 50 most recent cases of skull fracture for which a 4-film radiography series was available and 50 controls matched for age were reviewed. Two modules, containing a random sequence of 2- and 4-film series of each child, were constructed to have all children evaluated twice (once with 2 films and once with 4 films). Pediatric emergency physicians evaluated both modules 2 to 4 weeks apart. The interpretation of the 4-film series by a pediatric radiologist served as the criterion standard. The sensitivity and specificity of the 2-film versus the 4-film skull x-ray series, in the identification of fracture, were compared. RESULTS: Thirteen pediatric emergency physicians participated in the study. For sensitivity, the mean difference between the 2- and 4-view series was higher than the noninferiority margin of 0.055 with an absolute mean difference of 0.060 (4-view minus 2-view series) and a 1-sided 95% higher confidence limit of 0.099. However for specificity, the mean difference was within the margin with an absolute mean difference of 0.011 and a 1-sided 95% higher confidence limit of 0.033. CONCLUSIONS: For children sustaining a head trauma, the 2-film skull radiography series is not as sensitive as the 4-film series in the detection of fracture, when interpreted by pediatric emergency physicians.

Dynamic Volumetric Computed Tomography Angiography is an Effective Method to Evaluate Tracheomalacia in Children.

OBJECTIVE: Standard methods to evaluate tracheal pathology in children, including bronchoscopy, may require general anesthesia. Conventional dynamic proximal airway imaging in noncooperative children requires endotracheal intubation and/or medically induced apnea, which may affect airway mechanics and diagnostic performance. We describe a technique for unsedated dynamic volumetric computed tomography angiography (DV-CTA) of the proximal airway and surrounding vasculature in children and evaluate its performance compared to the reference-standard of rigid bronchoscopy. METHODS: Children who had undergone DV-CTA and bronchoscopy in one-year were retrospectively identified. Imaging studies were reviewed by an expert reader blinded to the bronchoscopy findings of primary or secondary tracheomalacia. Airway narrowing, if present, was characterized as static and/or dynamic, with tracheomalacia defined as >50% collapse of the tracheal cross-sectional area in exhalation. Pearson correlation was used for comparison. RESULTS: Over a 19-month period, we identified 32 children (median age 8 months, range 3-14 months) who had undergone DV-CTA and bronchoscopy within a 90-day period of each other. All studies were unsedated and free-breathing. The primary reasons for evaluation included noisy breathing, stridor, and screening for tracheomalacia. There was excellent agreement between DV-CTA and bronchoscopy for diagnosis of tracheomalacia (κ = 0.81, p < 0.001), which improved if children (n = 25) had the studies within 30 days of each other (κ = 0.91, p < 0.001). CTA provided incremental information on severity, and cause of secondary tracheomalacia. CONCLUSION: For most children, DV-CTA requires no sedation or respiratory manipulation and correlates strongly with bronchoscopy for the diagnosis of tracheomalacia. LEVEL OF EVIDENCE: 3 Laryngoscope, 133:410-416, 2023.

(UO2)2[UO4(trz)2](OH)2: a U(VI) coordination intermediate between a tetraoxido core and a uranyl ion with cation-cation interactions.

A uranyl triazole (UO(2))(2)[UO(4)(trz)(2)](OH)(2) (1) (trz = 1,2,4-triazole) was prepared using a mild solvothermal reaction of uranyl acetate with 1,2,4-triazole. Single-crystal X-ray diffraction analysis of 1 revealed it contains sheets of uranium-oxygen polyhedra and that one of the U(VI) cations is in an unusual coordination polyhedron that is intermediate between a tetraoxido core and a uranyl ion. This U(VI) cation also forms cation-cation interactions (CCIs). Infrared, Raman, and XPS spectra are provided, together with a thermogravimetric analysis that demonstrates breakdown of the compound above 300 °C. The UV-vis-NIR spectrum of 1 is compared to those of another compound that has a range of U(VI) coordination enviromments.

Identification, Isolation and characterization of a novel azoreductase from Clostridium perfringens.

Azo dyes are used widely in the textile, pharmaceutical, cosmetic and food industries as colorants and are often sources of environmental pollution. There are many microorganisms that are able to reduce azo dyes by use of an azoreductase enzyme. It is through the reduction of the azo bonds of the dyes that carcinogenic metabolites are produced thereby a concern for human health. The field of research on azoreductases is growing, but there is very little information available on azoreductases from strict anaerobic bacteria. In this study, the azoreductase gene was identified in Clostridium perfringens, a pathogen that is commonly found in the human intestinal tract. C. perfringens shows high azoreductase activity, especially in the presence of the common dye Direct Blue 15. A gene that encodes for a flavoprotein was isolated and expressed in Escherichia coli, and further purified and tested for azoreductase activity. The azoreductase (known as AzoC) was characterized by enzymatic reaction assays using different dyes. AzoC activity was highest in the presence of two cofactors, NADH and FAD. A strong cofactor effect was shown with some dyes, as dye reduction occurred without the presence of the AzoC (cofactors alone). AzoC was shown to perform best at a pH of 9, at room temperature, and in an anaerobic environment. Enzyme kinetics studies suggested that the association between enzyme and substrate is strong. Our results show that AzoC from C. perfringens has azoreductase activity.

U(VI) uranyl cation-cation interactions in framework germanates.

The isomorphous compounds NH(4)[(UO(6))(2)(UO(2))(9)(GeO(4))(GeO(3)(OH))] (1), K[(UO(6))(2)(UO(2))(9)(GeO(4))(GeO(3)(OH))] (2), Li(3)O[(UO(6))(2)(UO(2))(9)(GeO(4))(GeO(3)(OH))] (3), and Ba[(UO(6))(2)(UO(2))(9)(GeO(4))(2)] (4) were synthesized by hydrothermal reaction at 220 °C. The structures were determined using single crystal X-ray diffraction and refined to R(1) = 0.0349 (1), 0.0232 (2), 0.0236 (3), 0.0267 (4). Each are trigonal, P(3)1c. 1: a = 10.2525(5), c = 17.3972(13), V = 1583.69(16) Å(3), Z = 2; 2: a = 10.226(4), c = 17.150(9), V = 1553.1(12) Å(3), Z = 2; 3: a = 10.2668(5), c = 17.0558(11), V = 1556.94(15) Å(3), Z = 2; 4: a = 10.2012(5), c = 17.1570(12), V = 1546.23(15) Å(3), Z = 2. There are three symmetrically independent U sites in each structure, two of which correspond to typical (UO(2))(2+) uranyl ions and the other of which is octahedrally coordinated by six O atoms. One of the uranyl ions donates a cation-cation interaction, and accepts a different cation-cation interaction. The linkages between the U-centered polyhedra result in a relatively dense three-dimensional framework. Ge and low-valence sites are located within cavities in the framework of U-polyhedra. Chemical, thermal, and spectroscopic characterizations are provided.

The Zipperator! A Novel Model to Simulate Penile Zipper Entrapment.

Audience: The Zipperator training model is designed for emergency medicine resident physicians and physicians. Introduction: Zipper entrapment injuries are an uncommon cause of penile injury in the emergency department, representing an incidence of less than 0.5% of pediatric emergency department visits.1 However, they are one of the most common causes of genital injuries in young boys.1,2 Various methods proposed for releasing the entrapped tissue range from the use of mineral oil as lubrication to techniques to release the zipper mechanism or, in extreme cases, surgical procedures.3-6 A well-designed simulated task trainer would allow learners to practice these methods in a controlled environment conducive to learning 7,8. Given the low frequency of the chief complaint and with a wide variety of release techniques available, the purpose of this study was to build a simulation model that could improve learner confidence in troubleshooting this rarely performed procedure. Although past studies have designed similar task trainers, this novel model was built using a low-cost device ("Operation") to provide real-time alarm noises that reasonably simulate distress and procedural anxiety for both the patient and provider. Although pain and anxiety are separate outcomes from zipper entrapment release, including a component of these emotions may mimic the same emotional states that patients, their parental unit, and perhaps their provider may experience regarding this chief complaint given its rarity, anatomic vulnerability, and the overall sensitivity of the complaint's nature. Educational Objectives: After training on the Zipperator, learners will be able to:Demonstrate at least two techniques for zipper release and describe how methods would extrapolate to a real patient.Verbalize increased comfort with the diagnosis of zipper entrapment.Present a plan of care for this low-volume, high-anxiety presentation. Educational Methods: As part of a voluntary Emergency Medicine curriculum at two different sites, we constructed an inexpensive model for penile zipper entrapment using a household gameboard, "Operation," and materials that are easily obtainable and assembled in any emergency department. "Operation" was selected for its ability to produce alarm noises in response to excessive movement, which would reasonably simulate distress and procedural anxiety that may be experienced by both the patient and provider. This task trainer was used to teach medical students and post graduate year (PGY) 1-4 resident learners. A brief hypothetical situation was presented to learners, highlighting patient and paternal unit anxiety. Following this, learners were given a survey and asked to complete pre-model training questions immediately prior to using the simulated model. Learners were then given the opportunity for hands-on skills-based practice. Postmodel training questions were made available in the same survey immediately following the exercise. Research Methods: This exercise was offered at two sites over a two-year period. Sixty learners participated in the exercise. Participation was voluntary, was not graded nor shared with the residency director, and all feedback was formative in nature. Selected faculty and research assistants provided asynchronous opportunities for learners to practice on the model. Before the exercise, the faculty or research assistant on site presented a brief hypothetical situation to simulate patient and paternal unit anxiety that could be expected in this chief complaint. Each learner was then allowed to select a variety of tools and methods to practice zipper entrapment release. Learners were asked to begin a survey prior to training on the model, and then complete the survey immediately after training on the model to evaluate its educational value. The survey created for this study consisted of a structured questionnaire that contained close-ended questions. Measures evaluated include experience with prior zipper entrapments, comfort with zipper entrapments before and after training on the simulated model, and user experience. Results: Before the exercise, 68.3% of learners described their comfort with managing future zipper entrapments as very uncomfortable or totally uncomfortable. Although only 8.3% of learners had treated the zipper entrapment complaint prior to the exercise, 100% of those who had experienced treating the complaint felt that the simulated model was at least somewhat reflective of their experience with a real patient. 71.7% of the learners found the experience enjoyable, although 20% found the experience totally unenjoyable, of note, for unclear reasons and with unclear significance or etiology. After the exercise, 71.7% of learners indicated they felt comfortable to very comfortable regarding future cases of zipper entrapment. Discussion: Through the use of a well-known household board game and supplies commonly found in the emergency department, we created a simulated model that could be easily replicated. This simple model provided practice of the hand motions necessary for zipper entrapment release, as well as familiarity with the mental and physical approaches to dislodging the entrapment. The resident physicians who had had a prior zipper entrapment patient reported the model was somewhat similar to actual patient encounters. Overall, this model was well-received by the learners, with most expressing it was enjoyable and feeling it increased their confidence for treating this chief complaint. Some learners had noted the experience was totally unenjoyable. This measure may not be an appropriate endpoint, however, and incongruencies may be addressed by implementing prizes or friendly competition for enjoyment. Another limitation of this study is the leap taken between movement and patient comfort. While possible that learners can manipulate the model to reduce movement of the needle without meaningful reduction in zipper movement, observation by the instructor was sufficient to ensure this finding was not observed in our learner population. We therefore submit this cheap, simple model as a potential method to teach approaches to teaching a low frequency, high anxiety chief complaint. Topics: Penile entrapment model, penile entrapment release, Emergency Medicine, Urology, Clinical/Procedural Skills Training.

Syntheses, structures, and characterization of open-framework uranyl germanates.

Three uranyl germanates, Cs(2)[(UO(2))(Ge(2)O(6))](H(2)O) (1), Ag[(UO(2))(2)(HGe(2)O(7))](H(2)O) (2), and Ag(2)[(UO(2))(3)(GeO(4))(2)](H(2)O)(2) (3) were synthesized under hydrothermal conditions, and their structures were determined by single crystal X-ray diffraction. Compound 1 crystallizes in space group P2(1)/n, a = 7.9159(2) A, b = 21.5949(5) A, c = 12.4659(3) A, beta = 96.964(1) degrees, V = 2115.24(9) A(3), Z = 8; 2 is orthorhombic Ama2, a = 7.124(1) A, b = 10.771(2) A, c = 14.024(1) A, V = 1076.2(4) A(3), Z = 4; 3 is orthorhombic Pnma, a = 10.0462(6) A, b = 7.4699(5) A, c = 17.776(1) A, V = 1334.0(2) A(3), Z = 4. These compounds are frameworks of uranyl square (1) or pentagonal (2, 3) bipyramids and four-membered rings of germanate tetrahedra (1), dimers of germanate tetrahedra (2), or chains of GeO(5) triangular bipyramids (3). There are channels through each of the frameworks that contain the low-valence cations and the H(2)O groups. Compound 1 dehydrates upon heating, but the framework remains intact to at least 900 degrees C.