Numerical modeling of mesoscale infrasound propagation in the Arctic.

The impacts of characteristic weather events and seasonal patterns on infrasound propagation in the Arctic region are simulated numerically. The methodology utilizes wide-angle parabolic equation methods for a windy atmosphere with inputs provided by radiosonde observations and a high-resolution reanalysis of Arctic weather. The calculations involve horizontal distances up to 200 km for which interactions with the troposphere and lower stratosphere dominate. Among the events examined are two sudden stratospheric warmings, which are found to weaken upward refraction by temperature gradients while creating strongly asymmetric refraction from disturbances to the circumpolar winds. Also examined are polar low events, which are found to enhance negative temperature gradients in the troposphere and thus lead to strong upward refraction. Smaller-scale and topographically driven phenomena, such as low-level jets, katabatic winds, and surface-based temperature inversions, are found to create frequent surface-based ducting out to 100 km. The simulations suggest that horizontal variations in the atmospheric profiles, in response to changing topography and surface property transitions, such as ice boundaries, play an important role in the propagation.

Motivating Adherence to Exercise Plans Through a Personalized Mobile Health App: Enhanced Action Design Research Approach.

BACKGROUND: Physical inactivity is a global issue that affects people's health and productivity. With the advancement of mobile technologies, many apps have been developed to facilitate health self-management. However, few studies have examined the effectiveness of these mobile health (mHealth) apps in motivating exercise adherence. OBJECTIVE: This study aims to demonstrate the enhanced action design research (ADR) process and improve the design of mHealth apps for exercise self-management. Specifically, we investigate whether sending motivational messages improves adherence to exercise plans, whether the motivational effect is affected by personality, the impact of message type and repetition, and the process of involving a field experiment in the design process and learning new design principles from the results. METHODS: This formative research was conducted by proposing an enhanced ADR process. We incorporated a field experiment into the process to iteratively refine and evaluate the design until it converges into a final mHealth app. We used the Apple ResearchKit to develop the mHealth app and promoted it via trainers at their gyms. We targeted users who used the app for at least two months. Participants were randomly assigned to 1 of the 12 groups in a 2×3×2 factorial design and remained blinded to the assigned intervention. The groups were defined based on personality type (thinking or feeling), message type (emotional, logical, or none), and repetition (none or once). Participants with different personality types received tailored and repeated messages. Finally, we used the self-reported completion rate to measure participants' adherence level to exercise plans. By analyzing users' usage patterns, we could verify, correct, and enhance the mHealth app design principles. RESULTS: In total, 160 users downloaded the app, and 89 active participants remained during the 2-month period. The results suggest a significant main effect of personality type and repetition and a significant interaction effect between personality type and repetition. The adherence rate of people with feeling personality types was 18.15% higher than that of people with thinking types. Emotional messages were more effective than logical messages in motivating exercise adherence. Although people received repeated messages, they were more likely to adhere to exercise plans. With repeated reminders, the adherence rates of people with thinking personality types were significantly improved by 27.34% (P<.001). CONCLUSIONS: This study contributes to the literature on mHealth apps. By incorporating a field experiment into the ADR process, we demonstrate the benefit of combining design science and field experiments. This study also contributes to the research on mHealth apps. The principles learned from this study can be applied to improve the effectiveness of mHealth apps. The app design can be considered a foundation for the development of more advanced apps for specific diseases, such as diabetes and asthma, in future research.

Spatio-temporal focal spot characterization and modeling of the NIF ARC kilojoule picosecond laser.

The advanced radiographic capability (ARC) laser system, part of the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory, is a short-pulse laser capability integrated into the NIF. The ARC is designed to provide adjustable pulse lengths of ∼1-38ps in four independent beamlets, each with energies up to 1 kJ (depending on pulse duration). A detailed model of the ARC lasers has been developed that predicts the time- and space-resolved focal spots on target for each shot. Measurements made to characterize static and dynamic wavefront characteristics of the ARC are important inputs to the code. Modeling has been validated with measurements of the time-integrated focal spot at the target chamber center (TCC) at low power, and the space-integrated pulse duration at high power, using currently available diagnostics. These simulations indicate that each of the four ARC beamlets achieves a peak intensity on target of up to a few 1018W/cm2.

Data-driven malaria prevalence prediction in large densely populated urban holoendemic sub-Saharan West Africa.

Over 200 million malaria cases globally lead to half-million deaths annually. The development of malaria prevalence prediction systems to support malaria care pathways has been hindered by lack of data, a tendency towards universal "monolithic" models (one-size-fits-all-regions) and a focus on long lead time predictions. Current systems do not provide short-term local predictions at an accuracy suitable for deployment in clinical practice. Here we show a data-driven approach that reliably produces one-month-ahead prevalence prediction within a densely populated all-year-round malaria metropolis of over 3.5 million inhabitants situated in Nigeria which has one of the largest global burdens of P. falciparum malaria. We estimate one-month-ahead prevalence in a unique 22-years prospective regional dataset of > 9 × 104 participants attending our healthcare services. Our system agrees with both magnitude and direction of the prediction on validation data achieving MAE ≤ 6 × 10-2, MSE ≤ 7 × 10-3, PCC (median 0.63, IQR 0.3) and with more than 80% of estimates within a (+ 0.1 to - 0.05) error-tolerance range which is clinically relevant for decision-support in our holoendemic setting. Our data-driven approach could facilitate healthcare systems to harness their own data to support local malaria care pathways.

Expert-level automated malaria diagnosis on routine blood films with deep neural networks.

Over 200 million malaria cases globally lead to half a million deaths annually. Accurate malaria diagnosis remains a challenge. Automated imaging processing approaches to analyze Thick Blood Films (TBF) could provide scalable solutions, for urban healthcare providers in the holoendemic malaria sub-Saharan region. Although several approaches have been attempted to identify malaria parasites in TBF, none have achieved negative and positive predictive performance suitable for clinical use in the west sub-Saharan region. While malaria parasite object detection remains an intermediary step in achieving automatic patient diagnosis, training state-of-the-art deep-learning object detectors requires the human-expert labor-intensive process of labeling a large dataset of digitized TBF. To overcome these challenges and to achieve a clinically usable system, we show a novel approach. It leverages routine clinical-microscopy labels from our quality-controlled malaria clinics, to train a Deep Malaria Convolutional Neural Network classifier (DeepMCNN) for automated malaria diagnosis. Our system also provides total Malaria Parasite (MP) and White Blood Cell (WBC) counts allowing parasitemia estimation in MP/µL, as recommended by the WHO. Prospective validation of the DeepMCNN achieves sensitivity/specificity of 0.92/0.90 against expert-level malaria diagnosis. Our approach PPV/NPV performance is of 0.92/0.90, which is clinically usable in our holoendemic settings in the densely populated metropolis of Ibadan. It is located within the most populous African country (Nigeria) and with one of the largest burdens of Plasmodium falciparum malaria. Our openly available method is of importance for strategies aimed to scale malaria diagnosis in urban regions where daily assessment of thousands of specimens is required.

Analysis and prediction of unplanned intensive care unit readmission using recurrent neural networks with long short-term memory.

BACKGROUND: Unplanned readmission of a hospitalized patient is an indicator of patients' exposure to risk and an avoidable waste of medical resources. In addition to hospital readmission, intensive care unit (ICU) readmission brings further financial risk, along with morbidity and mortality risks. Identification of high-risk patients who are likely to be readmitted can provide significant benefits for both patients and medical providers. The emergence of machine learning solutions to detect hidden patterns in complex, multi-dimensional datasets provides unparalleled opportunities for developing an efficient discharge decision-making support system for physicians and ICU specialists. METHODS AND FINDINGS: We used supervised machine learning approaches for ICU readmission prediction. We used machine learning methods on comprehensive, longitudinal clinical data from the MIMIC-III to predict the ICU readmission of patients within 30 days of their discharge. We incorporate multiple types of features including chart events, demographic, and ICD-9 embeddings. We have utilized recent machine learning techniques such as Recurrent Neural Networks (RNN) with Long Short-Term Memory (LSTM), by this we have been able to incorporate the multivariate features of EHRs and capture sudden fluctuations in chart event features (e.g. glucose and heart rate). We show that our LSTM-based solution can better capture high volatility and unstable status in ICU patients, an important factor in ICU readmission. Our machine learning models identify ICU readmissions at a higher sensitivity rate of 0.742 (95% CI, 0.718-0.766) and an improved Area Under the Curve of 0.791 (95% CI, 0.782-0.800) compared with traditional methods. We perform in-depth deep learning performance analysis, as well as the analysis of each feature contribution to the predictive model. CONCLUSION: Our manuscript highlights the ability of machine learning models to improve our ICU decision-making accuracy and is a real-world example of precision medicine in hospitals. These data-driven solutions hold the potential for substantial clinical impact by augmenting clinical decision-making for physicians and ICU specialists. We anticipate that machine learning models will improve patient counseling, hospital administration, allocation of healthcare resources and ultimately individualized clinical care.

Longitudinal assessment of reprocessing effectiveness for colonoscopes and gastroscopes: Results of visual inspections, biochemical markers, and microbial cultures.

BACKGROUND: Flexible endoscopes are currently reused following cleaning and high-level disinfection. Contamination has been found on endoscopes, and infections have been linked to gastrointestinal, respiratory, and urologic endoscopes. METHODS: This longitudinal study involved visual inspections with a borescope, microbial cultures, and biochemical tests for protein and adenosine triphosphate to identify endoscopes in need of further cleaning or maintenance. Three assessments were conducted over a 7-month period. Control group endoscopes reprocessed using customary practices were compared with intervention group endoscopes subjected to more rigorous reprocessing. RESULTS: At final assessment, all endoscopes (N = 20) had visible irregularities. Researchers observed fluid (95%), discoloration, and debris in channels. Of 12 (60%) endoscopes with microbial growth, 4 had no growth until after 48 hours. There were no significant differences in culture results by study group, assessment period, or endoscope type. Similar proportions of control and intervention endoscopes (~20%) exceeded postcleaning biochemical test benchmarks. Adenosine triphosphate levels were higher for gastroscopes than colonoscopes (P = .014). Eighty-five percent of endoscopes required repair due to findings. CONCLUSIONS: More rigorous reprocessing was not consistently effective. Seven-day incubation allowed identification of slow-growing microbes. These findings bolster the need for routine visual inspection and cleaning verification tests recommended in new reprocessing guidelines.

Assessing residual contamination and damage inside flexible endoscopes over time.

Researchers evaluated flexible endoscope damage and contamination levels at baseline and 2 months later. Postcleaning test results exceeded benchmarks for all gastroscopes and no colonoscopes. Microbial growth was found in samples from 47% of fully reprocessed endoscopes at baseline and 60% at follow-up. Borescope examinations identified scratches, discoloration, debris, and fluid inside endoscopes. Irregularities changed over time. Study evaluations allowed damaged and contaminated endoscopes to be identified and re-reprocessed or sent for repairs.

Simethicone residue remains inside gastrointestinal endoscopes despite reprocessing.

BACKGROUND: During a study designed to assess endoscope reprocessing effectiveness, a borescope was used to examine lumens and ports. Cloudy, white, viscous fluid was observed inside fully reprocessed gastroscopes and colonoscopes. This fluid resembled simethicone, which is commonly administered to reduce foam and bubbles that impede visualization during gastrointestinal endoscopy. This article describes methods used to determine whether the observed fluid contained simethicone. METHODS: Photographs of residual fluid were taken using a borescope. Sterile cotton-tipped swabs were used to collect samples of fluid observed in 3 endoscope ports. Samples were evaluated using Fourier transform infrared spectroscopy (FTIR)-attenuated total reflection analysis. RESULTS: Residual fluid was observed inside 19 of 20 endoscopes. Fluid photographed in 8 endoscopes resembled simethicone solutions. FTIR analysis confirmed the presence of simethicone in 2 endoscopes. CONCLUSIONS: Fluid containing simethicone remained inside endoscopes despite reprocessing. Simethicone is an inert, hydrophobic substance that may reduce reprocessing effectiveness. Simethicone solutions commonly contain sugars and thickeners, which may contribute to microbial growth and biofilm development. Studies are needed to assess the prevalence of residual moisture and simethicone in endoscopes and determine the impact on reprocessing effectiveness. We recommend minimizing the use of simethicone pending further research into its safety.

Practical toolkit for monitoring endoscope reprocessing effectiveness: Identification of viable bacteria on gastroscopes, colonoscopes, and bronchoscopes.

BACKGROUND: Experts have recommended microbiologic surveillance by external reference laboratories for certain flexible endoscopes. There is currently insufficient evidence on the feasibility and utility of cultures. Researchers evaluated a preassembled toolkit for collecting and processing samples from endoscopes. METHODS: A pilot study was performed in a large academic medical center. A toolkit was used to aseptically sample biopsy ports and suction/biopsy channels of 5 gastroscopes, 5 colonoscopes, and 5 bronchoscopes after full reprocessing. Blinded specimens were packaged and transported on icepacks to a reference laboratory that used standard methodologies for microbial cultures. RESULTS: The laboratory detected bacteria in samples from 60% of patient-ready endoscopes, including gram-positive and gram-negative species. Viable microbes (<10 CFU) were recovered from 2 gastroscopes, 3 colonoscopes, and 4 bronchoscopes. Stenotrophomonas maltophilia and Delftia acidovorans were recovered from all 3 endoscope types. Subsequent environmental testing detected S maltophilia in the reprocessing rinse water. CONCLUSIONS: A preassembled toolkit facilitated the aseptic collection of samples for culturing by a reference laboratory that detected viable microbes on fully reprocessed endoscopes. Speciation allowed identification of potential pathogens and a possible common contamination source, demonstrating that microbial cultures may have value even when colony counts are low.

A randomized controlled trial comparing a low-residue diet versus clear liquids for colonoscopy preparation: impact on tolerance, procedure time, and adenoma detection rate.

OBJECTIVE: To achieve an excellent bowel preparation, it is routine to require a clear liquid diet on the day before the procedure. Unfortunately, this dietary modification may be poorly tolerated. We examine whether a change in precolonoscopy dietary restriction can lead to better patient tolerance without compromising examination quality. METHODS: This is a prospective, blinded, randomized controlled trial of patients undergoing screening or surveillance colonoscopy. The primary objective measures the effect of dietary modification on bowel prep quality. Secondary endpoints include polyp detection, patient tolerance, withdrawal time, and patient acceptance. A total of 200 patients were randomized to either (a) a low-residue diet for breakfast and lunch the day before the procedure or (b) clear liquids all day before the procedure. All patients underwent an identical low-volume sodium sulfate split prep. Bowel prep quality was scored using the Boston Bowel Preparation Scale (BBPS). A t test with TOST was used for noninferiority. Secondary endpoints were compared using χ analysis. RESULTS: Overall, 96.5% of patients had a good or excellent bowel prep (BBPS=6, 7, 8, or 9). LRD prep quality was noninferior to CLD prep quality (LRD 7.8 vs. CLD 8.1). Polyp detection rates were similar (68% vs. 65.4%, P=0.6899). Patient tolerance and acceptance did not differ. Withdrawal times were equivalent between both groups (16.2 vs. 16.5 min, P=NS). CONCLUSIONS: Patients allowed to have a limited low-residue diet before colonoscopy achieve a bowel prep quality that is noninferior to patients on a strict clear liquid diet limitation. Furthermore, polyp detection rates, patient tolerance, and patient acceptance were similar between the 2 groups.

Thermochromic and photoresponsive cyanometalate Fe/Co squares: toward control of the electron transfer temperature.

Two structurally related and photoresponsive cyanide-bridged Fe/Co square complexes, {Fe2Co2}, are reported: {[(Tp(Me))Fe(CN)3]2[Co(bpy)2]2[(Tp(Me))Fe(CN)3]2}·12H2O (2) and {[(Tp(Me))Fe(CN)3]2[Co(bpy)2]2[BPh4]2}·6MeCN (3), where Tp(Me) and bpy are hydridotris(3-methylpyrazol-1-yl)borate and 2,2'-bipyridine, respectively. Through electrochemical and spectroscopic studies, the Tp(Me) ligand appears to be a moderate σ donor in comparison to others in the [NEt4][(Tp(R))Fe(III)(CN)3] series [where Tp(R) = Tp, hydridotris(pyrazol-1-yl)borate; Tp(Me) = hydridotris(3-methylpyrazol-1-yl)borate; pzTp = tetrakis(pyrazol-1-yl)borate; Tp* = hydridotris(3,5-dimethylpyrazol-1-yl)borate; Tp*(Me) = hydridotris(3,4,5-trimethylpyrazol-1-yl)borate]. The spectroscopic, structural, and magnetic data of the {Fe2Co2} squares indicate that thermally-induced intramolecular electron transfer reversibly converts {Fe(II)LS(µ-CN)Co(III)LS} pairs into {Fe(III)LS(µ-CN)Co(II)HS} units near ca. 230 and 244 K (T1/2) for 2 and 3, respectively (LS: low spin; HS: high spin). These experimental results show that 2 and 3 display light-induced {Fe(III)LS(µ-CN)Co(II)HS} metastable states that relax to thermodynamic {Fe(II)LS(µ-CN)Co(III)LS} ones at ca. 90 K. Ancillary Tp(R) ligand donor strength appears to be the dominant factor for tuning electron transfer properties in these {Fe2Co2} complexes.

Synthesis and electrochemical reactivity of molybdenum dicarbonyl supported by a redox-active α-diimine ligand.

Low-valent molybdenum dicarbonyl complexes with a diazabutadiene [(mes)DAB(R); [ArN═C(R)C(R)═NAr]; Ar = 2,4,6-trimethylphenyl (mes), R = H or CH3] ligand have been synthesized and fully characterized. The title complexes exhibit elongated DAB C-N and shortened C-C bond lengths over the free ligand and other zerovalent molybdenum complexes of DAB. Compared to known examples theoretically described as iminato π-radicals (L(•-)), the oxidation state assignment fits a molybdenum(II) description. However, Mo K-edge X-ray absorption spectroscopy indicates that the complexes are best described as molybdenum(0). This example demonstrates that caution should be exercised in assigning the oxidation state based on structural parameters alone. Cyclic voltammetry studies reveal an electrochemical-chemical process that has been identified by in situ Fourier transform infrared spectroelectrochemistry as cis-to-trans isomerization.

Stable ruthenium nitrosyl porphyrins with axial O-bonded ligands; preparation and redox behavior.

The six-coordinate compounds, (T(p-OMe)PP)Ru(NO)(OC6HF4) and (T(p-OMe)PP)Ru(NO)(OC(=O)CF3) have been prepared and characterized by IR and NMR spectroscopy, electrochemistry and IR spectroelectrochemistry, and by X-ray crystallography. These compounds undergo macrocycle-centered oxidations, and loss of axial ligands upon reduction.

Ultralow-loss silicon ring resonators.

We experimentally demonstrate silicon ring resonators with internal quality factors of Q(0)=2.2×10(7), corresponding to record 2.7 dB/m propagation losses. Importantly, we show that these propagation losses are limited by bend loss, indicating that the propagation loss limit for silicon has not yet been reached.

Retooling manganese(III) porphyrin-based peroxynitrite decomposition catalysts for selectivity and oral activity: a potential new strategy for treating chronic pain.

Redox-active metalloporphyrins represent the most well-characterized class of catalysts capable of attenuating oxidative stress in vivo through the direct interception and decomposition of superoxide and peroxynitrite. While many interesting pharmacological probes have emerged from these studies, few catalysts have been developed with pharmaceutical properties in mind. Herein, we describe our efforts to identify new Mn(III)-porphyrin systems with enhanced membrane solubilizing properties. To this end, seven new Mn(III)-tetracyclohexenylporphyin (TCHP) analogues, 7, 10, 12, 15, and 16a-c, have been prepared in which the beta-fused cyclohexenyl rings provide a means to shield the charged metal center from the membrane during passive transport. Compounds 7, 15, and 16a-c have been shown to be orally active and potent analgesics in a model of carrageenan-induced thermal hyperalgesia. In addition, oral administration of compound 7 (10-100 mg/kg, n=5) has been shown to dose dependently reverse mechano-allodynia in the CCI model of chronic neuropathic pain.

Randomized controlled trial of toothbrushing to reduce ventilator-associated pneumonia pathogens and dental plaque in a critical care unit.

AIM: To investigate the effect of a powered toothbrush on colonization of dental plaque by ventilator-associated pneumonia (VAP)-associated organisms and dental plaque removal. MATERIALS AND METHODS: Parallel-arm, single-centre, examiner- and analyst-masked randomized controlled trial. Forty-six adults were recruited within 48 h of admission. Test intervention: powered toothbrush, control intervention: sponge toothette, both used four times per day for 2 min. Groups received 20 ml, 0.2% chlorhexidine mouthwash at each time point. RESULTS: The results showed a low prevalence of respiratory pathogens throughout with no statistically significant differences between groups. A highly statistically significantly greater reduction in dental plaque was produced by the powered toothbrush compared with the control treatment; mean plaque index at day 5, powered toothbrush 0.75 [95% confidence interval (CI) 0.53, 1.00], sponge toothette 1.35 (95% CI 0.95, 1.74), p=0.006. Total bacterial viable count was also highly statistically significantly lower in the test group at day 5; Log(10) mean total bacterial counts: powered toothbrush 5.12 (95% CI 4.60, 5.63), sponge toothette 6.61 (95% CI 5.93, 7.28), p=0.002. CONCLUSIONS: Powered toothbrushes are highly effective for plaque removal in intubated patients in a critical unit and should be tested for their potential to reduce VAP incidence and health complications.

Facile determination of the spectra of unstable electrode products using simultaneous fiber-optic chronoabsorptometry and chronoamperometry.

A widely applicable fiber-optic UV-vis method to determine the spectra of in situ generated redox products and intermediates at or near an electrode surface is described mathematically and implemented experimentally. The quantitative spectral information obtained gives extinction coefficients (absorptivities) as a function of wavelength, requires no arbitrary subtraction of the spectrum of the starting material, and is relatively insensitive to path length and concentration during the spectroelectrochemical measurements. We demonstrate proof-of-concept of this methodology by reproducing the expected spectrum of the ferrocenium ion from electrooxidation of ferrocene in MeCN, and by reproducing the spectrum that reveals π-radical cation formation from the electrooxidation of (T(p-OMe)PP)Co(NO) ((T(p-OMe)PP = 5,10,15,20-tetra(p-methoxyphenyl)porphyrinato dianion). Importantly, we demonstrate its use for the facile detection of unstable redox products not previously detected by current spectroelectrochemical methods. We obtain, for the first time, the experimental UV-vis spectrum of the short-lived fac-[(dppe)Mn(CO)(3)Br](+) cation, a hitherto uncharacterized intermediate that forms during the archetypal redox-induced fac-to-mer isomerization of (dppe)Mn(CO)(3)Br (dppe = diphenylphosphinoethane). Spectral features of the Mn-containing species have been verified by comparison to theoretical spectra calculated by time-dependent density functional theory methods.