Risk reductions during pyrene biotransformation and mobilization in a model plant-bacteria-biochar system.

The productive application of motile microorganisms for degrading hydrophobic contaminants in soil is one of the most promising processes in modern remediation due to its sustainability and low cost. However, the incomplete biodegradation of the contaminants and the formation of the intermediary metabolites in the process may increase the toxicity in soil during bioremediation, and motile inoculants may mobilize the pollutants through biosorption. Therefore, controlling these factors should be a fundamental part of soil remediation approaches. The aim of this study was to evaluate the sources of risk associated with the cometabolism-based transformation of 14C-labeled pyrene by inoculated Pseudomonas putida G7 and identify ways to minimize risk. Our model scenario examined the increase in bioaccessibility to a distant source of contamination facilitated by sunflower (Helianthus annuus L.) roots. A biochar trap for mobilized pollutant metabolites and bacteria has also been employed. The experimental design consisted of pots filled with a layer of sand with 14C-labeled pyrene (88 mg kg-1) as a contamination focus located several centimeters from the inoculation point. Half of the pots included a biochar layer at the bottom. The pots were incubated in a greenhouse with sunflower plants and P. putida G7 bacteria. Pots with sunflower plants showed a higher biodegradation of pyrene, its mobilization as metabolites through the percolate and the roots, and bacterial mobilization toward the source of contamination, also resulting in increased pyrene transformation. In addition, the biochar layer efficiently reduced the concentrations of pyrene metabolites collected in the leachates. Therefore, the combination of plants, motile bacteria and biochar safely reduced the risk caused by the biological transformation of pyrene.

Benefit and cost of repeating a severe acute respiratory coronavirus virus 2 (SARS-CoV-2) polymerase chain reaction (PCR) test after the second day of hospitalization in five hospitals during various community prevalences and vaccination rates.

At our hospital, universal severe acute respiratory coronavirus virus 2 (SARS-CoV-2) polymerase chain reaction (PCR) testing was performed upon admission and again after 2 inpatient days. As community-wide prevalence, admission, and vaccination rates varied, the number needed to benefit fluctuated between 16 and 769 and the cost per additional detection fluctuated between $800 and $29,400. These 2 metrics were negatively associated with new hospital admissions. No other community indicator was associated with the number needed to benefit and cost per additional detection.

Role of tactic response on the mobilization of motile bacteria through micrometer-sized pores.

A major cause of high bioremediation endpoints is the limited bioaccessibility to residual contaminants resting in soil pores with diameters close to the size exclusion limit of bacterial cells. Under nongrowing conditions and in the absence of hydraulic flow, we examined how the tactic behavior of motile, contaminant-degrading Pseudomonas putida G7 cells (2 × 1 µm) influenced passage through membranes with pores ranging in size from 1 µm to 12 µm. The bacteria were spontaneously retained by the membranes - even those with the largest pore size. However, the cells were mobilized through 5 µm and 12 µm pores after the application of an attractant (salicylate). Mobilization also occurred by attraction to the common root exudate constituents γ-aminobutyric acid and citrate and repellence (or negative taxis) to zero-valent iron nanoparticles. The observed pore size threshold for tactic mobilization (5 µm) and unaltered cell fluxes and effective cell diffusion against different chemoeffector strengths and concentrations suggest that there is a physical constraint on the gradient sensing mechanism at the pores that drives the tactic response. Our results indicate that chemically mediated, small-scale tactic reactions of motile bacteria may become relevant to enhance the bioaccessibility of the residual contaminants present in micrometer-sized soil pores.

Distinct Roles of the Human Subthalamic Nucleus and Dorsal Pallidum in Parkinson's Disease Impulsivity.

BACKGROUND: Impulsivity and impulse control disorders are common in Parkinson's disease and lead to increased morbidity and reduced quality of life. Impulsivity is thought to arise from aberrant reward processing and inhibitory control, but it is unclear why deep brain stimulation of either the subthalamic nucleus (STN) or globus pallidus internus (GPi) affects levels of impulsivity. Our aim was to assess the role of the STN and GPi in impulsivity using invasive local field potential (LFP) recordings from deep brain stimulation electrodes. METHODS: We measured LFPs during a simple rewarding Go/NoGo paradigm in 39 female and male human patients with Parkinson's disease manifesting variable amounts of impulsivity who were undergoing unilateral deep brain stimulation of either the STN (18 nuclei) or GPi (28 nuclei). We identified reward-specific LFP event-related potentials and correlated them to impulsivity severity. RESULTS: LFPs in both structures modulated during reward-specific Go and NoGo stimulus evaluation, reward feedback, and loss feedback. Motor and limbic functions were anatomically separable in the GPi but not in the STN. Across participants, LFP reward processing responses in the STN and GPi uniquely depended on the severity of impulsivity. CONCLUSIONS: This study establishes LFP correlates of impulsivity within the STN and GPi regions. We propose a model for basal ganglia reward processing that includes the bottom-up role of the GPi in reward salience and the top-down role of the STN in cognitive control.

Wearable sensor-driven responsive deep brain stimulation for essential tremor.

BACKGROUND: Deep brain stimulation (DBS) is an effective surgical therapy for individuals with essential tremor (ET). However, DBS operates continuously, resulting in adverse effects such as postural instability or dysarthria. Continuous DBS (cDBS) also presents important practical issues including limited battery life of the implantable neurostimulator (INS). Collectively, these shortcomings impact optimal therapeutic benefit in ET. OBJECTIVE: The goal of the study was to establish a physiology-driven responsive DBS (rDBS) system to provide targeted and personalized therapy based on electromyography (EMG) signals. METHODS: Ten participants with ET underwent rDBS using Nexus-D, a Medtronic telemetry wand that acts as a direct conduit to the INS by modulating stimulation voltage. Two different rDBS paradigms were tested: one driven by one EMG (single-sensor) and another driven by two or more EMGs (multi-sensor). The feature(s) used in the rDBS algorithms was the pow2er in the participant's tremor frequency band derived from the sensors controlling stimulation. Both algorithms were trained on kinetic and postural data collected during DBS off and cDBS states. RESULTS: Using established clinical scales and objective measurements of tremor severity, we confirm that both rDBS paradigms deliver equivalent clinical benefit as cDBS. Moreover, both EMG-driven rDBS paradigms delivered less total electrical energy translating to an increase in the battery life of the INS. CONCLUSIONS: The results of this study verify that EMG-driven rDBS provides clinically equivalent tremor suppression compared to cDBS, while delivering less total electrical energy. Controlling stimulation using a dynamic rDBS paradigm can mitigate limitations of traditional cDBS systems.

Urinary tract infection stewardship: A urinary antibiogram and electronic medical record alert nudging narrower-spectrum antibiotics for urinary tract infections.

An antimicrobial stewardship intervention consisting of a urinary antibiogram and an electronic health record best-practice advisory promoted narrower-spectrum antibiotics for uncomplicated urinary tract infections in hospitalized patients. Over 20 months, the intervention significantly reduced ceftriaxone orders by 48% (P < .001) and increased cefazolin use 19 times from baseline (P < .001).

Vascular effects of serelaxin in patients with stable coronary artery disease: a randomized placebo-controlled trial.

AIMS: The effects of serelaxin, a recombinant form of human relaxin-2 peptide, on vascular function in the coronary microvascular and systemic macrovascular circulation remain largely unknown. This mechanistic, clinical study assessed the effects of serelaxin on myocardial perfusion, aortic stiffness, and safety in patients with stable coronary artery disease (CAD). METHODS AND RESULTS: In this multicentre, double-blind, parallel-group, placebo-controlled study, 58 patients were randomized 1:1 to 48 h intravenous infusion of serelaxin (30 µg/kg/day) or matching placebo. The primary endpoints were change from baseline to 47 h post-initiation of the infusion in global myocardial perfusion reserve (MPR) assessed using adenosine stress perfusion cardiac magnetic resonance imaging, and applanation tonometry-derived augmentation index (AIx). Secondary endpoints were: change from baseline in AIx and pulse wave velocity, assessed at 47 h, Day 30, and Day 180; aortic distensibility at 47 h; pharmacokinetics and safety. Exploratory endpoints were the effect on cardiorenal biomarkers [N-terminal pro-brain natriuretic peptide (NT-proBNP), high-sensitivity troponin T (hsTnT), endothelin-1, and cystatin C]. Of 58 patients, 51 were included in the primary analysis (serelaxin, n = 25; placebo, n = 26). After 2 and 6 h of serelaxin infusion, mean placebo-corrected blood pressure reductions of -9.6 mmHg (P = 0.01) and -13.5 mmHg (P = 0.0003) for systolic blood pressure and -5.2 mmHg (P = 0.02) and -8.4 mmHg (P = 0.001) for diastolic blood pressure occurred. There were no between-group differences from baseline to 47 h in global MPR (-0.24 vs. -0.13, P = 0.44) or AIx (3.49% vs. 0.04%, P = 0.21) with serelaxin compared with placebo. Endothelin-1 and cystatin C levels decreased from baseline in the serelaxin group, and there were no clinically relevant changes observed with serelaxin for NT-proBNP or hsTnT. Similar numbers of serious adverse events were observed in both groups (serelaxin, n = 5; placebo, n = 7) to 180-day follow-up. CONCLUSION: In patients with stable CAD, 48 h intravenous serelaxin reduced blood pressure but did not alter myocardial perfusion.

Safety and efficacy of the cystic fibrosis transmembrane conductance regulator potentiator icenticaftor (QBW251).

BACKGROUND: This is the first-in-human study of icenticaftor, an oral potentiator of the cystic fibrosis (CF) transmembrane conductance regulator (CFTR) channel. Restoration of CFTR activity has shown significant clinical benefits, but more studies are needed to address all CFTR mutations. METHODS: Safety, pharmacodynamics/pharmacokinetics of icenticaftor were evaluated in a randomized, double-blind, placebo-controlled study in healthy volunteers. Efficacy was assessed in adult CF patients with ≥1 pre-specified CFTR Class III or IV mutation (150 and 450 mg bid), or homozygous for F508del mutation (450 mg bid). Primary efficacy endpoint was change from baseline in lung clearance index (LCI2.5). Secondary endpoints included %predicted FEV1 and sweat chloride level. RESULTS: Class IV mutations were present in 22 patients, Class III in 2 (both S549N), and 25 were homozygous for F508del. Icenticaftor was well-tolerated in healthy and CF subjects with no unexpected events or discontinuations in the CF groups. The most frequent study-drug related adverse events in CF patients were nausea (12.2%), headache (10.2%), and fatigue (6.1%). Icenticaftor 450 mg bid for 14 days showed significant improvements in all endpoints versus placebo in patients with Class III and IV mutations; mean %predicted FEV1 increased by 6.46%, LCI2.5 decreased by 1.13 points and sweat chloride decreased by 8.36 mmol/L. No significant efficacy was observed in patients homozygous for a single F508del. CONCLUSIONS: Icenticaftor was safe and well-tolerated in healthy volunteers and CF patients, and demonstrated clinically meaningful changes in lung function and sweat chloride level in CF patients with Class III and IV CFTR mutations. ClinicalTrials.gov: NCT02190604.

Root-mediated bacterial accessibility and cometabolism of pyrene in soil.

Partial transformation of pollutants and mobilization of the produced metabolites may contribute significantly to the risks resulting from biological treatment of soils polluted by hydrophobic chemicals such as polycyclic aromatic hydrocarbons (PAHs). Pyrene, a four-ringed PAH, was selected here as a model pollutant to study the effects of sunflower plants on the bacterial accessibility and cometabolism of this pollutant when located at a spatially distant source within soil. We compared the transformation of passively dosed 14C-labeled pyrene in soil slurries and planted pots that were inoculated with the bacterium Pseudomonas putida G7. This bacterium combines flagellar cell motility with the ability to cometabolically transform pyrene. Cometabolism of this PAH occurred immediately in the inoculated and shaken soil slurries, where the bacteria had full access to the passive dosing devices (silicone O-rings). Root exudates did not enhance the survival of P. putida G7 cells in soil slurries, but doubled their transport in column tests. In greenhouse-incubated soil pots with the same pyrene sources instead located centimeters from the soil surface, the inoculated bacteria transformed 14C-labeled pyrene only when the pots were planted with sunflowers. Bacterial inoculation caused mobilization of 14C-labeled pyrene metabolites into the leachates of the planted pots at concentrations of approximately 1 mg L-1, ten times greater than the water solubility of the parent compound. This mobilization resulted in a doubled specific root uptake rate of 14C-labeled pyrene equivalents and a significantly decreased root-to-fruit transfer rate. Our results show that the plants facilitated bacterial access to the distant pollutant source, possibly by increasing bacterial dispersal in the soil; this increased bacterial access was associated with cometabolism, which contributed to the risks of biodegradation.

Sustainably reducing device utilization and device-related infections with DeCATHlons, device alternatives, and decision support.

Engagement of frontline staff, along with senior leadership, in competition-style healthcare-associated infection reduction efforts, combined with electronic clinical decision support tools, appeared to reduce antibiotic regimen initiations for urinary tract infections (P = .01). Mean monthly standardized infection and device utilization ratios also decreased (P < .003 and P < .0001, respectively).

Florida research open-source synchronization tool (FROST) for electrophysiology experiments.

BACKGROUND: Accurate interpretation of electrophysiological data in cognitive and behavioral experiments requires the acquisition of time labels, such as marking the exact start of a condition or moment a stimulus is presented to a research subject. NEW METHOD: Here we present an inexpensive (∼30 USD) device used as a central relay for multiple peripheral devices, such as a computer screen presenting an experiment, a pressure-sensor push button, a multi-button responder, a pulse oximeter sensor, a light-emitting diode trigger for camera synchronization, and more. We refer to this device as the Florida Research Open-source Synchronization Tool (FROST). FROST allows for easy hardware and Arduino-based firmware modifications that enable a standard platform for the integration of novel peripheral sensors. RESULTS: With two examples, we demonstrate the application of this device during human research experiments: intracranial-electroencephalography (EEG) recordings in a patient with epilepsy and surface-EEG recordings in a healthy participant. We provide an example setup for a rodent experiment as well. We also demonstrate the timing delays of our device. COMPARISON WITH EXISTING METHODS: There is currently very few existing open-source synchronization tools for electrophysiological research that enable customization with new device compatibility. We developed this tool to enable widespread replication for many applications through an open-source platform. CONCLUSIONS: FROST can be easily adapted for research experiments beyond the included example cases. All materials are open-source at github.com/Brain-Mapping-Lab/FROST.

Biocomposites from Rice Straw Nanofibers: Morphology, Thermal and Mechanical Properties.

Agricultural residues are major potential resources for biomass and for material production. In this work, rice straw residues were used to isolate cellulose nanofibers of different degree of oxidation. Firstly, bleached rice fibers were produced from the rice straw residues following chemical extraction and bleaching processes. Oxidation of rice fibers mediated by radical 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) at pH 10 was then applied to extract rice cellulose nanofibers, with diameters of 3-11 nm from morphological analysis. The strengthening capacity of rice nanofibers was tested by casting nanocomposite films with poly(vinyl alcohol) polymer. The same formulations with eucalyptus nanofibers were produced as comparison. Their thermal and mechanical performance was evaluated using thermogravimetry, differential scanning calorimetry, dynamic mechanical analysis and tensile testing. The glass transition of nanocomposites was shifted to higher temperatures with respect to the pure polymer by the addition of rice cellulose nanofibers. Rice nanofibers also acted as a nucleating agent for the polymer matrix. More flexible eucalyptus nanofibers did not show these two phenomena on the matrix. Instead, both types of nanofibers gave similar stiffening (as Young's modulus) to the matrix reinforced up to 5 wt.%. The ultimate tensile strength of nanocomposite films revealed significant enhancing capacity for rice nanofibers, although this effect was somehow higher for eucalyptus nanofibers.

Development of a combined, sequential real-time fMRI and fNIRS neurofeedback system to enhance motor learning after stroke.

BACKGROUND: After stroke, wrist extension dyscoordination precludes functional arm/hand. We developed a more spatially precise brain signal for use in brain computer interface (BCI's) for stroke survivors. NEW METHOD: Combination BCI protocol of real-time functional magnetic resonance imaging (rt-fMRI) sequentially followed by functional near infrared spectroscopy (rt-fNIRS) neurofeedback, interleaved with motor learning sessions without neural feedback. Custom Matlab and Python code was developed to provide rt-fNIRS-based feedback to the chronic stroke survivor, system user. RESULTS: The user achieved a maximum of 71 % brain signal accuracy during rt-fNIRS neural training; progressive focus of brain activation across rt-fMRI neural training; increasing trend of brain signal amplitude during wrist extension across rt-fNIRS training; and clinically significant recovery of arm coordination and active wrist extension. COMPARISON WITH EXISTING METHODS: Neurorehabilitation, peripherally directed, shows limited efficacy, as do EEG-based BCIs, for motor recovery of moderate/severely impaired stroke survivors. EEG-based BCIs are based on electrophysiological signal; whereas, rt-fMRI and rt-fNIRS are based on neurovascular signal. CONCLUSION: The system functioned well during user testing. Methods are detailed for others' use. The system user successfully engaged rt-fMRI and rt-fNIRS neurofeedback systems, modulated brain signal during rt-fMRI and rt-fNIRS training, according to volume of brain activation and intensity of signal, respectively, and clinically significantly improved limb coordination and active wrist extension. fNIRS use in this case demonstrates a feasible/practical BCI system for further study with regard to use in chronic stroke rehab, and fMRI worked in concept, but cost and some patient-use issues make it less feasible for clinical practice.

Proceedings of the Seventh Annual Deep Brain Stimulation Think Tank: Advances in Neurophysiology, Adaptive DBS, Virtual Reality, Neuroethics and Technology.

The Seventh Annual Deep Brain Stimulation (DBS) Think Tank held on September 8th of 2019 addressed the most current: (1) use and utility of complex neurophysiological signals for development of adaptive neurostimulation to improve clinical outcomes; (2) Advancements in recent neuromodulation techniques to treat neuropsychiatric disorders; (3) New developments in optogenetics and DBS; (4) The use of augmented Virtual reality (VR) and neuromodulation; (5) commercially available technologies; and (6) ethical issues arising in and from research and use of DBS. These advances serve as both "markers of progress" and challenges and opportunities for ongoing address, engagement, and deliberation as we move to improve the functional capabilities and translational value of DBS. It is in this light that these proceedings are presented to inform the field and initiate ongoing discourse. As consistent with the intent, and spirit of this, and prior DBS Think Tanks, the overarching goal is to continue to develop multidisciplinary collaborations to rapidly advance the field and ultimately improve patient outcomes.

Parkinsonian Beta Dynamics during Rest and Movement in the Dorsal Pallidum and Subthalamic Nucleus.

In Parkinson's disease (PD), pathologically high levels of beta activity (12-30 Hz) reflect specific symptomatology and normalize with pharmacological or surgical intervention. Although beta characterization in the subthalamic nucleus (STN) of PD patients undergoing deep brain stimulation (DBS) has now been translated into adaptive DBS paradigms, a limited number of studies have characterized beta power in the globus pallidus internus (GPi), an equally effective DBS target. Our objective was to compare beta power in the STN and GPi during rest and movement in people with PD undergoing DBS. Thirty-seven human female and male participants completed a simple behavioral experiment consisting of periods of rest and button presses, leading to local field potential recordings from 19 (15 participants) STN and 26 (22 participants) GPi nuclei. We examined overall beta power as well as beta time-domain dynamics (i.e., beta bursts). We found higher beta power during rest and movement in the GPi, which also had more beta desynchronization during movement. Beta power was positively associated with bradykinesia and rigidity severity; however, these clinical associations were present only in the GPi cohort. With regards to beta dynamics, bursts were similar in duration and frequency in the GPi and STN, but GPi bursts were stronger and correlated to bradykinesia-rigidity severity. Beta dynamics therefore differ across basal ganglia nuclei. Relative to the STN, beta power in the GPi may be readily detected, modulates more with movement, and relates more to clinical impairment. Together, this could point to the GPi as a potentially effective target for beta-based adaptive DBS.SIGNIFICANCE STATEMENT It is known that subthalamic nucleus (STN) beta activity is linked to symptom severity in Parkinson's disease (PD), but few studies have characterized beta activity in the globus pallidus internus (GPi), another effective target for deep brain stimulation (DBS). We compared beta power in the STN and GPi during rest and movement in 37 people with PD undergoing DBS. We found that beta dynamics differed across basal ganglia nuclei. Our results show that, relative to the STN, beta power in the GPi may be readily detected, modulates more with movement, and relates more to clinical impairment. Together, this could point to the GPi as a potentially effective target for beta-based adaptive DBS.

Impact of bacterial motility on biosorption and cometabolism of pyrene in a porous medium.

The risks of pollution by polycyclic aromatic hydrocarbons (PAHs) may increase in bioremediated soils as a result of the formation of toxic byproducts and the mobilization of pollutants associated to suspended colloids. In this study, we used the motile and chemotactic bacterium Pseudomonas putida G7 as an experimental model for examining the potential role of bacterial motility in the cometabolism and biosorption of pyrene in a porous medium. For this purpose, we conducted batch and column transport experiments with 14C-labelled pyrene loaded on silicone O-rings, which acted as a passive dosing system. In the batch experiments, we observed concentrations of the 14C-pyrene equivalents well above the equilibrium concentration observed in abiotic controls. This mobilization was attributed to biosorption and cometabolism processes occurring in parallel. HPLC quantification revealed pyrene concentrations well below the 14C-based quantifications by liquid scintillation, indicating pyrene transformation into water-soluble polar metabolites. The results from transport experiments in sand columns revealed that cometabolic-active, motile cells were capable of accessing a distant source of sorbed pyrene. Using the same experimental system, we also determined that salicylate-mobilized cells, inhibited for pyrene cometabolism, but mobilized due to their tactic behavior, were able to sorb the compound and mobilize it by biosorption. Our results indicate that motile bacteria active in bioremediation may contribute, through cometabolism and biosorption, to the risk associated to pollutant mobilization in soils. This research could be the starting point for the development of more efficient, low-risk bioremediation strategies of poorly bioavailable contaminants in soils.

Optical and Piezoelectric Study of KNN Solid Solutions Co-Doped with La-Mn and Eu-Fe.

The solid-state method was used to synthesize single phase potassium-sodium niobate (KNN) co-doped with the La3+-Mn4+ and Eu3+-Fe3+ ion pairs. Structural determination of all studied solid solutions was accomplished by XRD and Rietveld refinement method. Electron paramagnetic resonance (EPR) studies were performed to determine the oxidation state of paramagnetic centers. Optical spectroscopy measurements, excitation, emission and decay lifetime were carried out for each solid solution. The present study reveals that doping KNN with La3+-Mn4+ and Eu3+-Fe3+ at concentrations of 0.5 mol % and 1 mol %, respectively, improves the ferroelectric and piezoelectric behavior and induce the generation of optical properties in the material for potential applications.

Analysis of acoustic frequency and wave amplitude generated by the Oscillatory Thoracic Thixotropic Device (Diottix(r)) in human chest / Análisis de la frecuencia acústica y amplitud de las ondas sonoras generadas por el Dispositivo Oscilatorio Torácico Tixotrópico (Diottix(r)) en el tórax humano / Análise da frequência acústica e amplitude das ondas sonoras geradas pelo Dispositivo Oscilatório Torácico Tixotrópico (Diottix(r)) no tórax humano

Diottix(r) was calibrated at 25 Hz to achieve the frequency indicated in literature as being effective to mobilize the airways secretions. However, the amplitude and frequency of the waves generated by the equipment in different regions of the chest still need to be investigated. The objective of this study was to analyze the frequency and amplitude of waves generated by Diottix(r) in chests of healthy subjects. Diottix(r) was used in the anterior and posterior regions of the chest. The mechanical waves were captured using stethoscopes connected to electret microphones, which were connected to a digital oscilloscope. Frequency and amplitude data were recorded by the stethoscope, positioned in six points in the anterior region and six in the posterior region of the chest, following the positions commonly used in pulmonary auscultation. Signals were recorded and transferred to a computer with software for their analysis. The frequency of waves did not present a significant change (from 24.9 to 26.4 Hz). The wave amplitude in the anterior versus the posterior region in each area of the lung, the upper, middle and lower, had differences. Diottix(r) produces frequencies in the chest according to the calibrated; thus, it can be a complementary resource to bronchial hygiene maneuvers. The amplitudes of waves seem to be affected by other structures like bone parts and heart.

Diottix(r) fue calibrado en 25 Hz para alcanzar la frecuencia indicada en la literatura como eficaz para movilizar secreciones de las vías aéreas. La amplitud y frecuencia de ondas generadas por el equipamiento en las diferentes regiones del tórax aun necesitan de más investigaciones. El objetivo de eso estudio fue analizar la frecuencia y amplitud de ondas generadas por el Diottix(r) en el tórax de sujetos saludables. La aplicación del Diottix(r) fue realizada en las regiones anterior y posterior del tórax. Las ondas mecánicas fueron captadas utilizándose estetoscopios ligados a micrófonos de electret, los cuales estaban ligados a uno osciloscopio digital. Los datos de frecuencia y amplitud fueron captados por lo estetoscopio posicionado en seis puntos en la región anterior y seis en la posterior del tórax, siguiendo las posiciones comúnmente utilizadas en la ausculta pulmonar. Los sígnales fueron registrados y transferidos para una computadora a través de un programa para su análisis de datos. La frecuencia de ondas no presentó variación significativa (del 24,9 al 26,4 Hz). La amplitud de onda en la región anterior versus posterior en cada segmento del pulmón, tercio superior, medio e inferior, presentó diferencia. Lo Diottix(r) produce frecuencias en el tórax según el calibrado. Por lo tanto, puede ser uno recurso complementar a las manobras de higiene de los bronquios. Las amplitudes de ondas parecen ser afectadas por otras estructuras, las cuales incluyen partes óseas y el corazón.

O Diottix(r) foi calibrado a 25 Hz para atingir a frequência indicada na literatura como eficaz a fim de mobilizar secreções de vias aéreas. A amplitude e a frequência das ondas geradas pelo equipamento nas diferentes regiões do tórax ainda precisam ser investigadas. O objetivo de estudo foi analisar a frequência e a amplitude das ondas geradas pelo Diottix(r) no tórax de indivíduos saudáveis. A aplicação do Diottix(r) foi realizada nas regiões anterior e posterior do tórax. As ondas mecânicas foram captadas utilizando estetoscópios conectados a microfones de eletreto, os quais estavam ligados a um osciloscópio digital. Os dados de frequência e amplitude foram captados pelo estetoscópio, posicionado em seis pontos na região anterior e seis na posterior do tórax, seguindo as posições comumente utilizadas na ausculta pulmonar. Os sinais foram registrados e transferidos para um computador por meio de um software para análise deles. A frequência das ondas não apresentou variação significativa (24,9 a 26,4 Hz). A amplitude de onda na região anterior versus posterior em cada segmento do pulmão, terço superior, médio e inferior, apresentou diferença. O Diottix(r) produz frequências no tórax de acordo com o calibrado; desta forma, pode ser um recurso complementar às manobras de higiene brônquica. As amplitudes de ondas parecem ser afetadas por outras estruturas, que incluem as partes ósseas e o coração.

Condensed-phase laser ionization time-of-flight mass spectrometry of highly energetic nitro-aromatic compounds.

RATIONALE: Analysis of explosive compounds represents an interesting field of work due to the obvious social relevance of these compounds. Direct laser ionization allows the analysis of these high internal energy compounds without sampling or preparation procedures. We have studied nitro-aromatic compounds to understand their mass spectra when directly ionized in the condensed phase, different from the gas-phase studies commonly conducted. METHODS: Direct condensed-phase laser ionization time-of-flight mass spectrometry of high energy density materials has been performed using a 5 ns width quadrupled Nd:YAG laser. No matrix assistance was used. Fine control of the laser energy allowed the study of the fragmentation processes from values close to the ionization threshold to ones where atomic-only mass spectra were recorded. RESULTS: The influence of the variation of extraction conditions on the recorded mass spectra was investigated. For low extraction width pulses, ions with low m/z values were mainly observed, whereas, at higher widths, higher mass fragment ions were also detected while the total ion current was maintained. Therefore, the mass spectra can be modulated to obtain mass spectra containing molecular or atomic information. The onset of ion generation for the different fragment ions was also studied, yielding information that can help to understand the processes involved in the fragmentation pathways of the molecule and in the dissociation mechanisms. Two sampling procedures allowed the prospective use of LIMS as a screening technique for nitro-aromatic-based highly energetic explosives. CONCLUSIONS: Direct analysis of explosive compounds has been performed by laser ionization. A large dependence of the resultant spectra on the laser energy was observed that might be useful for studies of fragmentation pathways. For forensic applications, two sampling procedures might allow the use of LIMS as a screening technique.