Spectral Array Research Articles

Removal of Background Drift Nonlinear Interference in 3-D Spectral Arrays for Multi-Way Calibration Using Trilinear Decomposition Methods

Fluorescent and phosphorescent techniques have been widely used in the fields of food, biology, environment, chemistry, medicine, life science and so on. However, the spectral background drift often occurs in the spectral excitation dimension, creating the need for new methods to process this phenomenon. There are many different factors which may lead to this common phenomenon, such as the changes in background noise of instrument or temperature. In the work, a new technique for removal of background drift in three-dimensional spectral arrays is proposed. The basic idea is to perform trilinear decomposition based on the alternating trilinear decomposition (ATLD) algorithm on the instrumental response data. In model building, the background drift is modeled as an additional component or factor as well as the analytes of interest and the interferents. As the optimum number of factors (N) is provided by the core consistency diagnostic (CORCONDIA), the ATLD algorithm is applied to decompose the raw data (Xraw) with the factor number of N, then three profile matrices A, B and C can be obtained. Vectors an, bn and cn that representing the signal of the background drift can be extracted from these matrices to construct a 3-D background drift data array (Xdrift ). After subtracting the Xdrift from the Xraw, the background drift is removed, leaving the new data on a flat baseline. Two simulated data sets were firstly employed to demonstrate the reasonability of the new method. The same and different levels of background drifts along the excitation dimension are added into the two simulated data sets, respectively. Then, it is successfully used to analyze two experimental data sets in which significant background drift are present. These results highlight the fact that this technique yields a good removal of background drift. In addition, the good result is obtained by secondary removal for serious background drift. The proposed method can be viewed as a good spectral pretreatment technique. Keywords chemometrics; alternating trilinear decomposition; three-dimensional spectral array; background drift; spectral pretreatment

Psychophysiological Effects of Orchid and Rose Fragrances on Humans

This study aimed to determine the effects of floral fragrances on human brain waves and moods. A total of 44 subjects participated in this experiment. Group 1 consisted of 11 male and 14 female college students with a mean age of 24.5 years (± 2.23) and Group 2 consisted of 10 males and 9 females with a mean age of 54.3 years (± 2.98). Subjects were exposed to floral fragrances of Rosa hybrida , ‘Hera’ (hereafter referred to as “rose”), Cymbidium faberi(hereafter referred to as “orchid”), or odorless control flowers (hereafter referred to as “control”). Experiments took place in three rooms (rose, orchid, and control). Electroencephalographs (EEGs) were recorded during exposure to the odors and the data were processed using quantitative electroencephalographic (QEEG) techniques. The changing EEG patterns wereanalyzed by brain mapping and compressed spectral arrays, and the subjects’ preferences (hedonic evaluations) were quantified with an A1 index. Increased activation of absolute alpha waves was verified on six of the eight EEG channels, with the right frontal and left occipital lobes exhibiting no changes and the left parietal region showing the greatest activation. According to the QEEG measurements in the electrode sites over the frontal, temporal, parietal, and occipital lobes, the strongest absolute alpha waves were induced in the parietal lobes, followed by the temporal lobes, with the other lobes showing no significant changes. On brain maps, the orchid fragrance induced greater absolute alpha and absolute mid-beta activities compared with the rose and control fragrances, and the rose fragrance induced high absolute mid-beta activation. To identify emotional responses to floral fragrances, the subjects were requested to fill in a questionnaire and the resulting odor-related emotional descriptors were analyzed using semantic differential and factor analysis. Principal component analysis identified “elegant” as the first principal component describing the floral fragrance, followed by “refreshing” and “aromatic.” The subjects gave orchid higher scores for “elegant” and “refreshing,” while finding rose more “aromatic.” Differences in hedonic evaluation revealed by the A1 index appeared in the 65-115 sec range of scent exposure time. The subjects with ages of around 50 years showed olfactory preferences throughout the entire experimental time of 160 sec, most markedly in the later time segment (115-165 sec), showing an increasing preference with increasing exposure time. We conclude that rose fragrance can improve concentration by creating an aromatic environment conducive to a concentrated and calm state of mind, and orchid fragrance can make people feel pampered and relaxed by creating an elegant and refreshing environment.

Color density spectral array of bilateral bispectral index system: Electroencephalographic correlate in comatose patients with nonconvulsive status epilepticus

Purposeto describe the characteristics of the color density spectral array (CDSA) of bilateral bispectral index (b-BIS) monitoring system in patients with comatose nonconvulsive status epilepticus (NCSE). We hypothesized that CDSA could be helpful for monitoring NCSE in critically subjects if continuous EEG (cEEG) is not available. Methodswe retrospectively analyzed comatose patients admitted to our neurological intensive care unit (NICU) from 2011 to 2014 with a diagnosis of definitive NCSE that underwent b-BIS monitoring for at least 24h to guide anesthetic sedation. Clinical, electroencephalography and neuroimaging findings were analyzed. Moreover, all parameters from the b-BIS data including the CDSA were reviewed during periods of NCSE (NCSE pattern) and profound sedation (sedation pattern). Results15 NCSE patients were included. The delay from the diagnosis of NCSE to the onset of b-BIS monitoring was 8 (0.5–31)h and total time of b-BIS monitoring 7.8±6.5 days. CDSA during NCSE pattern was characterized by continuous or intermittent red and dark red tones, spectral edge frequency (SEF) in the delta-theta range, with or without asymmetry and BIS number trend with significant variability. In contrast, CDSA during sedation revealed predominance of orange, yellow, green and occasionally blue tones, SEF in the alpha-beta range, absence of asymmetry and stability of BIS number. Conclusionsb-BIS monitoring system and, in particular, CDSA used by nonexpert NICU personnel may be helpful to follow-up episodes of NCSE, to detect recurrences of nonconvulsive seizures (NCSzs), and to monitor profound anesthetic therapy in comatose patients when cEEG is not available.

Changes in the composition of fatty acids and lipofuscin-like pigments during development of rat heart.

Postnatal heart development is characterized by critical periods of heart remodeling. In order to characterize the changes in the lipophilic fraction induced by free radicals, fatty acids and their oxidized products, lipofuscin-like pigments (LFP), were investigated. Fatty acids were analyzed by gas chromatography and LFP were studied by fluorescence techniques. A fluorophore characterized by spectral methods was further resolved by HPLC. Major changes in the composition of fatty acids occurred immediately after birth and then during maturation. Fluorescence of LFP changed markedly on postnatal days 1, 4, 8, and 14, and differed from the adult animals. LFP comprise several fluorophores that were present since fetal state till adulthood. No new major fluorophores were formed during development, just the abundances of individual fluorophores have been modulated which produced changes in the shape of the spectral arrays. HPLC resolved the fluorophore with excitation maximum at 360 nm and emission maximum at 410 nm. New chromatographically distinct species appeared immediately on postnatal day 1, and then on days 30 and 60. Consumption of polyunsaturated fatty acids immediately after birth and subsequent formation of LFP suggests that oxidative stress is involved in normal heart development.

3D Printing of Medicines: Engineering Novel Oral Devices with Unique Design and Drug Release Characteristics.

Three dimensional printing (3D printing) was used to fabricate novel oral drug delivery devices with specialized design configurations. Each device was loaded with multiple actives, with the intent of applying this process to the production of personalized medicines tailored at the point of dispensing or use. A filament extruder was used to obtain drug-loaded--paracetamol (acetaminophen) or caffeine--filaments of poly(vinyl alcohol) with characteristics suitable for use in fused-deposition modeling 3D printing. A multinozzle 3D printer enabled fabrication of capsule-shaped solid devices containing the drug with different internal structures. The design configurations included a multilayer device, with each layer containing drug, whose identity was different to the drug in the adjacent layers, and a two-compartment device comprising a caplet embedded within a larger caplet (DuoCaplet), with each compartment containing a different drug. Raman spectroscopy was used to collect 2-dimensional hyper spectral arrays across the entire surface of the devices. Processing of the arrays using direct classical least-squares component matching to produce false color representations of distribution of the drugs was used. This clearly showed a definitive separation between the drug layers of paracetamol and caffeine. Drug release tests in biorelevant bicarbonate media showed unique drug release profiles dependent on the macrostructure of the devices. In the case of the multilayer devices, release of both paracetamol and caffeine was simultaneous and independent of drug solubility. With the DuoCaplet design, it was possible to engineer either rapid drug release or delayed release by selecting the site of incorporation of the drug in the device; the lag-time for release from the internal compartment was dependent on the characteristics of the external layer. The study confirms the potential of 3D printing to fabricate multiple-drug containing devices with specialized design configurations and unique drug release characteristics, which would not otherwise be possible using conventional manufacturing methods.

Diagnostic Accuracy of Electrographic Seizure Detection by Neurophysiologists and Non-Neurophysiologists in the Adult ICU Using a Panel of Quantitative EEG Trends.

To evaluate the sensitivity and specificity of a panel of quantitative EEG (qEEG) trends for seizure detection in adult intensive care unit (ICU) patients when reviewed by neurophysiologists and non-neurophysiologists. One hour qEEG panels (n = 180) were collected retrospectively from 45 ICU patients and were distributed to 5 neurophysiologists, 7 EEG technologists, and 5 Neuroscience ICU nurses for evaluation of seizures. Each panel consisted of the following qEEG tools, displayed separately for left and right hemisphere electrodes: rhythmicity spectrogram (rhythmic run detection and display; Persyst Inc), color density spectral array, EEG asymmetry index, and amplitude integrated EEG. The reviewers did not have access to the raw EEG data. For the reviewer's ability to detect the presence of seizures on qEEG panels when compared with the gold standard of independent raw EEG review, the sensitivities and specificities are as follows: neurophysiologists 0.87 and 0.61, EEG technologists 0.80 and 0.80, and Neuroscience ICU nurses 0.87 and 0.61, respectively. There was no statistical difference among the three groups regarding sensitivity. Quantitative EEG display panels are a promising tool to aid detection of seizures by non-neurophysiologists as well as by neurophysiologists. However, even when used as a panel, qEEG trends do not appear to be adequate as the sole method for reviewing continuous EEG data.

Tungsten spectroscopy in the EUV range observed at a high-temperature superconducting electron-beam ion trap

We have recorded extreme ultraviolet spectra from ${\mathrm{W}}^{11+}$ to ${\mathrm{W}}^{15+}$ ions using a flat-field spectrometer installed at the Shanghai high-temperature superconducting electron-beam ion trap. The spectra were recorded at beam energies ranging between 200 and 400 eV and showed spectral lines and transition arrays in the 170--260 \AA{} region. The charge states and spectra transitions were identified by comparison with calculations using a detailed relativistic configuration interaction method and collisional-radiative model, both incorporated in the flexible atomic code. Atomic structure calculations showed that the dominant emission arises from $5d$ $\ensuremath{\rightarrow}$ $5p$ and $5p$ $\ensuremath{\rightarrow}$ $5s$ transitions. The work also identified the ground-state configuration of ${W}^{13+}$ as $4{f}^{13}5{s}^{2}$ both theoretically and experimentally.

Detection of electrographic seizures by critical care providers using color density spectral array after cardiac arrest is feasible.

To determine the accuracy and reliability of electroencephalographic seizure detection by critical care providers using color density spectral array electroencephalography. Tutorial and questionnaire. Critical care providers (attending physicians, fellow trainees, and nurses). A standardized powerpoint color density spectral array tutorial followed by classification of 200 color density spectral array images as displaying seizures or not displaying seizures. Using conventional electroencephalography recordings obtained from patients who underwent electroencephalography monitoring after cardiac arrest, we created 100 color density spectral array images, 30% of which displayed seizures. The gold standard for seizure category was electroencephalographer determination from the full montage conventional electroencephalography. Participants did not have access to the conventional electroencephalography tracings. After completing a standardized color density spectral array tutorial, images were presented to participants in duplicate and in random order. Twenty critical care physicians (12 attendings and eight fellows) and 19 critical care nurses classified the color density spectral array images as having any seizure(s) or no seizures. The 39 critical care providers had a color density spectral array seizure detection sensitivity of 70% (95% CI, 67-73%), specificity of 68% (95% CI, 67-70%), positive predictive value of 46%, and negative predictive value of 86%. The sensitivity of color density spectral array detection of status epilepticus was 72% (95% CI, 69-74%). Determining which post-cardiac arrest patients experience electrographic seizures by critical care providers is feasible after a brief training. There is moderate sensitivity for seizure and status epilepticus detection and a high negative predictive value.

A single cataluminescence sensor based on spectral array and its use in the identification of vinegars

The discrimination of complex mixtures, especially those with very similar compositions, remains a challenging part of chemical analysis. In this paper, a single cataluminescence (CTL) sensor constructed using MgO nanomaterials in a closed reaction cell (CRC) was used to identify vinegars. It may provide an archetype of this type of highly multicomponent system. By scanning the CTL spectra, which were distributed in 15 wavelengths during the reaction period, the spectral array patterns of the vinegars were obtained. These functioned as their fingerprints. The CTL signals of the array were then normalized and identified through linear discrimination analysis (LDA). Nine types and eight brands of vinegars and an additional series of artificial samples were tested; the new technique was found to distinguish between them very well. This single sensor demonstrated excellent promise for analysis of complex mixtures in real-world applications and may provide a novel method for identifying very similar complex analytes.

Continuous EEG monitoring in children in the intensive care unit (ICU)

Pediatric EEG in the intensive care unit (ICU) requires specific technical requirements in order to yield relevant data depending upon clinical scenario: diagnosis of electroclinical or subclinical seizures, their quantification before and after therapeutic changes and sometimes evaluation of severity of cortical dysfunction. The urgent nature of these indications implies the rapid set-up of the EEG system by qualified staff and possibility of maintaining the electrodes in place during long periods of time. Various techniques are available today for EEG monitoring, the interpretation of which depends on the contribution of an experienced physician. Among recent techniques, those most commonly used are trend curves obtained via signal analysis such as amplitude EEG (a-EEG) and density spectral array (DSA) or compressed spectral array (CSA). Trend curves enable the digital creation of a display graph containing several hours of transformed and compressed EEG recorded data. Visualized on one sole display graph, these trend curves can facilitate the identification of very slow changes in EEG background activity and their variation (alertness cycles, changes linked to treatment administrations) as well as seizure patterns and their quantification. In this chapter, we propose a brief overview of monitoring techniques, followed by a review of the various data yielded by EEG monitoring as well as the relevance of this type of management; finally, detailed clinical indications will be discussed after thorough analysis of the literature.

New infrared sensor technology mirror on-ground characterization

The new infrared sensor technology (NIRST) is an infrared radiometer on board the SAC-D/Aquarius mission, launched on June 10, 2011. It is composed of middle wave infrared (MWIR) and a long wave infrared (LWIR) cameras, with three arrays of 512 microbolometers each. The three MWIR camera arrays operate in the [3.4,4.2]-μm spectral range, whereas LWIR camera arrays 1 and 2 operate in the [10.4,11.3]-μm spectral range and array 3, in the [11.4,12.3]-μm spectral range. NIRST also has a pointing Be mirror that covers the range of [30 deg, 60 deg], where 45 deg corresponds to nadir pointing. The aim of this work is to present the on-ground NIRST mirror’s characterization. The characterization was performed in an ambient environment by acquiring data at three different pointing angles, β={30 deg;45 deg;60 deg}, at several blackbody sources’ temperatures for both cameras. The on-ground mirror characterization revealed that the laboratory blackbody sources used present a temperature gradient on their emitting surfaces. The results also reveal the system response to be affected by the pointing angle, i.e., the data at 60 deg was noisier that at 30 deg.

Non-expert use of quantitative EEG displays for seizure identification in the adult neuro-intensive care unit

Video-EEG monitoring is the ultimate way to diagnose non-convulsive status epilepticus (NCSE) in intensive care units (ICU). Usually EEG recordings are evaluated once a day by an electrophysiologist, which may lead to delay in diagnosis. Digital EEG trend analysis methods like amplitude integrated EEG (aEEG) and density spectral array (DSA) have been developed to facilitate recognition of seizures. In this study, we aimed to investigate the diagnostic utility of these methods by non-expert physicians and ICU nurses for NCSE identification in an adult neurological ICU. Ten patients with NCSE and ten control patients without seizures were included in the study. The raw EEG recordings of all subjects were converted to both aEEG and DSA and displayed simultaneously without conventional EEG. After training for seizure recognition with both methods, two physicians and two nurses analyzed the visual displays individually, and marked seizure timings. Their results were compared with those of a study epileptologist. Participants analyzed 615h of EEG data with 700 seizures. Overall, 63% of the seizures were recognized by all, 15.6% by three, 11.6% by two, 8.3% by one rater and only 1.5% were missed by all of them (sensitivity was 88-99%, and specificity was 89-95% when the ratings were assessed as 1-h epochs). False positive rates were 1 per 2h in the study and 1 per 6h in the control groups. Interrater agreement was high (κ=0.79-0.81). Bilateral independent seizures and ictal recordings with lower amplitude and shorter duration were more likely to be missed. There was no difference in performance between the rating of physicians and nurses. Our study demonstrates that bedside nurses, ICU fellows and residents can achieve acceptable level of accuracy for seizure identification using the digital EEG trend analysis methods following brief training. This may help earlier notification of the electrophysiologist who is not always available in ICUs.

Io's hot spots in the near-infrared detected by LEISA during the New Horizons flyby

The New Horizons spacecraft flew past Jupiter and its moons in February and March 2007. The flyby provided one of the most comprehensive inventories of Io's active plumes and hot spots yet taken, including the large 350 km high eruption of Tvashtar. Among the suite of instruments active during the flyby was the Linear Etalon Infrared Spectral Array (LEISA), a near-infrared imaging spectrometer covering the spectral range 1.25 to 2.5 µm. We have identified 37 distinct hot spots on Io in the nine LEISA spectral image cubes taken during the flyby. We describe the thermal emissions from these volcanoes and fit single-component blackbody curves to the hot spot spectra to derive eruption temperatures, areas, and power output for the hot spots with sufficient signal-to-noise. Of these, 11 hot spots were seen by LEISA more than once, and East Girru showed short-term variability over a few days, also seen by other New Horizons instruments. This work presents a comprehensive look at the global distribution of Io's volcanism at the time of the flyby. From these measurements, we estimate the global power output of high-temperature (>550 K) volcanism on Io to be ~8 TW. This work provides the first short-wavelength near-infrared survey with global coverage at all longitudes on the nightside of Io without sunlight contamination at these wavelengths. A major conclusion from this study is that 90% of all the volcanoes observed in the New Horizons LEISA near-infrared data in 2007 were also observed during the Galileo epoch, suggesting these are all long-lived hot spots.

Spectrogram screening of adult EEGs is sensitive and efficient.

Quantitatively evaluate whether screening with compressed spectral arrays (CSAs) is a practical and time-effective protocol for assisting expert review of continuous EEG (cEEG) studies in hospitalized adults. Three neurophysiologists reviewed the reported findings of the first 30 minutes of 118 cEEGs, then used CSA to guide subsequent review ("CSA-guided review" protocol). Reviewers viewed 120 seconds of raw EEG data surrounding suspicious CSA segments. The same neurophysiologists performed independent page-by-page visual interpretation ("conventional review") of all cEEGs. Independent conventional review by 2 additional, more experienced neurophysiologists served as a gold standard. We compared review times and detection rates for seizures and other pathologic patterns relative to conventional review. A total of 2,092 hours of cEEG data were reviewed. Average times to review 24 hours of cEEG data were 8 (±4) minutes for CSA-guided review vs 38 (±17) minutes for conventional review (p < 0.005). Studies containing seizures required longer review: 10 (±4) minutes for CSA-guided review vs 44 (±20) minutes for conventional review (p < 0.005). CSA-guided review was sensitive for seizures (87.3%), periodic epileptiform discharges (100%), rhythmic delta activity (97.1%), focal slowing (98.7%), generalized slowing (100%), and epileptiform discharges (88.5%). CSA-guided review reduces cEEG review time by 78% with minimal loss of sensitivity compared with conventional review. This study provides Class IV evidence that screening of cEEG with CSAs efficiently and accurately identifies seizures and other EEG abnormalities as compared with standard cEEG visual interpretation.

Spatio-temporal variability of seismic noise above a geothermal reservoir

Abstract We report on the application of seismic noise investigations, including H/V (horizontal to vertical) spectral ratio and array techniques, to a shallow gas-rich geothermal reservoir in Heybeli, southwestern Turkey. Fundamental resonant frequencies were determined to estimate the sediment thickness. Using small-scale seismic arrays, phase velocity dispersion curves were derived by correlating noise recordings according to the extended spatial autocorrelation method. Improved shear wave velocity profiles were estimated by combining Rayleigh wave dispersion curves and horizontal to vertical spectral ratios in a joint inversion. We found that the velocities obtained for the reservoir site are higher than those for a location outside the reservoir. In addition to the fundamental resonant peaks in the spectra, a clear 6-Hz-signal could be identified originating from the center of the geothermal field, repeatedly observed in 2010 and 2011. It had been claimed that low frequency (1–10 Hz) seismic signal anomalies were correlated with the occurrence of hydrocarbons. One of the physical mechanisms under consideration to explain these tremor-like signals above such reservoirs is resonant amplification due to the oscillation of bubbles. Based on the signal similarity with volcanic tremors, it is not a priori given that the liquid phase must be oil for resonance effects to occur. We therefore applied array techniques to identify potential noise originating from the Heybeli reservoir. In fact, the frequency–wavenumber ( f – k ) method clearly indicated a noise source coming from the main production well of the reservoir. In 2011, as part of our assessment, the operators of the spa facility stopped the extraction of thermal water for 2 h: the 6-Hz-signal disappeared after the pump had been stopped and reappeared after the pump began operating again. Thus, the 6-Hz-signal is likely of artificial origin. In addition, no natural noise source inside the reservoir could be identified.

Orthogonal dispersive spectral-domain optical coherence tomography

Ultrahigh depth range spectral domain optical coherence tomography (SDOCT) can be realized based on the orthogonal dispersive spectrometer consisted by a high spectral resolution virtually-imaged phased array (VIPA) and a low spectral resolution grating. However, two critical issues result in the challenge of obtaining desirable one-dimensional (1-D) spectra from the recorded two-dimensional (2-D) orthogonal spectra for high-quality OD-SDOCT imaging. One is the wavenumber mapping errors and the other is the periodic intensity modulations. The paper proposes a method for desirable reconstruction of 1-D spectra from the recorded 2-D orthogonal spectra. A sample etalon with identical parameters to the dispersive VIPA is used to determine the free spectrum range (FSR) of the VIPA, and spectral phases from two reflecting mirrors are further applied for broadband wavenumber calibration. The cascading of column spectra are performed from interval of four lines of column spectra, and four records of cascaded 1-D spectra are obtained and then averaged to alleviate the periodic intensity modulations. Broadband 1-D spectra are thus reconstructed with an ultrahigh spectral resolution. To demonstrate the feasibility of the proposed method, three typical samples are imaged by the OD-SDOCT system.

Beyond the Double Banana

To investigate whether extending the 10-20 array with 6 electrodes in the inferior temporal chain and constructing computed montages increases the diagnostic value of ictal EEG activity originating in the temporal lobe. In addition, the accuracy of computer-assisted spectral source analysis was investigated. Forty EEG samples were reviewed by 7 EEG experts in various montages (longitudinal and transversal bipolar, common average, source derivation, source montage, current source density, and reference-free montages) using 2 electrode arrays (10-20 and the extended one). Spectral source analysis used source montage to calculate density spectral array, defining the earliest oscillatory onset. From this, phase maps were calculated for localization. The reference standard was the decision of the multidisciplinary epilepsy surgery team on the seizure onset zone. Clinical performance was compared with the double banana (longitudinal bipolar montage, 10-20 array). Adding the inferior temporal electrode chain, computed montages (reference free, common average, and source derivation), and voltage maps significantly increased the sensitivity. Phase maps had the highest sensitivity and identified ictal activity at earlier time-point than visual inspection. There was no significant difference concerning specificity. The findings advocate for the use of these digital EEG technology-derived analysis methods in clinical practice.

Brain activity monitoring by compressed spectral array during deep hypothermic circulatory arrest in acute aortic dissection surgery.

IntroductionMonitoring the central nervous system during aortic dissection repair may improve the understanding of the intraoperative changes related to its bioactivity.AimThe aim of the study was to evaluate the influence of deep hypothermia on intraoperative brain bioactivity measured by the compressed spectral array (CSA) method and to assess the influence of the operations on postoperative cognitive function.Material and methodsThe study enrolled 40 patients (31 men and 9 women) at the mean age of 60.2 ± 8.6 years, diagnosed with acute aortic dissection. They underwent emergency operations in deep hypothermic circulatory arrest (DHCA). During the operations, brain bioactivity was monitored with the compressed spectral array method.ResultsThere were no intraoperative deaths. Electrocerebral silence during DHCA was observed in 31 patients (74%). The lowest activity was observed during DHCA: it was 0.01 ± 0.05 nW in the left hemisphere and 0.01 ± 0.03 nW in the right hemisphere. The postoperative results of neurological tests deteriorated statistically significantly (26.9 ± 1.7 points vs. 22.0 ± 1.7 points; p < 0.001), especially among patients who exhibited brain activity during DHCA.ConclusionsThe compressed spectral array method is clinically useful in monitoring brain bioactivity during emergency operations of acute aortic dissections. Electrocerebral silence occurs in 75% of patients during DHCA. The cognitive function of patients deteriorates significantly after operations with DHCA.

Changes in Density Spectral Array of BIS VISTA Monitoring System in Epilepsy Surgery

We report the case of a patient with drug resistant epilepsy scheduled for amygdalohippocampectomy (AHS). During this type of surgery, Density Spectral Array (DSA) belonging to the Bilateral Bispectral Index (BIS) VISTATM Monitoring System (BVMS) was used. DSA, but no BIS trend, was helpful to detect differences in the power spectrum between both cerebral hemispheres during propofol- remifentanyl-dexmedetomidine anesthesia. This case provides novel evidence to support the clinical utility of DSA in monitoring depth of anaesthesia and sedation.

Living Matter Observations with a Novel Hyperspectral Supercontinuum Confocal Microscope for VIS to Near-IR Reflectance Spectroscopy

A broad range hyper-spectroscopic microscope fed by a supercontinuum laser source and equipped with an almost achromatic optical layout is illustrated with detailed explanations of the design, implementation and data. The real novelty of this instrument, a confocal spectroscopic microscope capable of recording high resolution reflectance data in the VIS-IR spectral range from about 500 nm to 2.5 μm wavelengths, is the possibility of acquiring spectral data at every physical point as defined by lateral coordinates, X and Y, as well as at a depth coordinate, Z, as obtained by the confocal optical sectioning advantage. With this apparatus we collect each single scanning point as a whole spectrum by combining two linear spectral detector arrays, one CCD for the visible range, and one InGaAs infrared array, simultaneously available at the sensor output channel of the home made instrument. This microscope has been developed for biomedical analysis of human skin and other similar applications. Results are shown illustrating the technical performances of the instrument and the capability in extracting information about the composition and the structure of different parts or compartments in biological samples as well as in solid statematter. A complete spectroscopic fingerprinting of samples at microscopic level is shown possible by using statistical analysis on raw data or analytical reflectance models based on Abelés matrix transfer methods.