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Objective The study aimed to investigate factors contributing to heat development during light curing of a flowable bulk-fill resin-based composite (SDRTM, Lot # 602000876, Dentsply Sirona, Konstanz, Germany) (RBC). Materials and Methods Temperatures were measured with calibrated thermocouples. A multi-wave light-emitting diode (LED) light curing unit (LCU) was used (Ivoclar Vivadent, Schaan, Lichtenstein). In all experiments, the RBC was first cured (cured) for 30 s and, after 5 min of recovery time, received a second LCU irradiation (post-cured) for 30 s. The exothermic reaction was measured by calculating the Δ temperature between cured and post-cured RBC. In a cylinder-shaped polymer mold, temperature was recorded inside of RBC during curing (part 1) and light transmission through RBC during curing was investigated (part 2). Pulpal temperatures were assessed in an extracted third molar during light curing (part 3). Data were statistically analyzed using one-way ANOVA (α=0.05). Results Increased thickness of RBC led to decreased pulp chamber temperatures. Inside RBC, there was a large variation in heat development between the cured and post-cured groups (p

INTRODUCTION Autologous fat grafting (AFG) is a popular and effective method of breast reconstruction after mastectomy; however, the oncological safety of AFG remains in question. The aim of this study was to determine whether AFG increases the risk of cancer recurrence in the reconstructed breast. METHODS A matched, case-control study was conducted from 2000 to 2017 at the senior author's institution. Inclusion was limited to female patients who underwent mastectomy and breast reconstruction with or without AFG. Data were further subdivided at the breast level. χ analyses were used to test the association between AFG status and oncologic recurrence. A Cox proportional-hazards model was constructed to assess for possible differences in time to oncologic recurrence. The probability of recurrence was determined by Kaplan-Meier analyses and confirmed with log-rank testing. RESULTS Overall, 428 breasts met study criteria. Of those, 116 breasts (27.1%) received AFG, whereas 312 (72.9%) did not. No differences in the rates of oncologic recurrence were found between the groups (8.2% vs 9.0%, P < 1.000). Unadjusted (hazard ratio = 1.03, confidence interval = 0.41-2.60, P < 0.957) and adjusted hazard models showed no statistically significant increase in time to oncologic recurrence when comparing AFG to non-AFG. In addition, no statistical differences in disease-free survival were found (P = 0.96 by log rank test). CONCLUSION Autologous fat grafting for breast reconstruction is oncologically safe and does not increase the likelihood of oncologic recurrence. Larger studies (eg, meta analyses) with longer follow-up are needed to further elucidate the long-term safety of AFG as a reconstructive adjunct.

A common effort for both military and civil healthcare is to achieve knowledge-based health care in cold weather injuries and fatal accidents in harsh arctic environment. The Cold Weather Operations Conference in November 2021, having more than 300 participants from 20 countries, was addressing the prevention and treatment of injuries and trauma care in cold weather conditions and the challenges for military prehospital casualty care. The intention of the programme was to stimulate further research and systematic knowledge-based clinical work. The abstracts from the conference present cold weather research and clinical experience relevant for readers of the International Journal of Circumpolar Health.

The soundscape of the Northeast Pacific Ocean is studied with emphasis on frequencies in the range 63–125 Hz. A 34-year (1964–1998) increase and seasonal fluctuations (1994–2006) are investigated. This is achieved by developing a simple relationship between the total radiated power of all ocean sound sources and the spatially averaged mean-square sound pressure in terms of the average source factor, source depth, and sea surface temperature (SST). The formula so derived is used to predict fluctuations in the sound level in the range 63–125 Hz with an amplitude of 1.2 dB and a period of 1 year associated with seasonal variations in the SST, which controls the amount of sound energy trapped in the sound fixing and ranging (SOFAR) channel. Also investigated is an observed 5 dB increase in the same frequency range in the Northeast Pacific Ocean during the late 20th century [Andrew, Howe, Mercer, and Dzieciuch (2002). ARLO 3, 65–70]. The increase is explained by the increase in the total number of ocean-going ships and their average gross tonnage.

The deep inferior epigastric perforator (DIEP) flap has become the first choice in autologous breast reconstruction, as excellent aesthetic results can be obtained with minimal donor site morbidity. However, rates of fat necrosis for DIEP breast reconstruction may be as high as 35%, which not only reduces the aesthetic result but also causes uncertainty due to lump formation in the reconstructed breast.1,2 Fat necrosis is a result of inadequate flap perfusion. Selection of a suitable perforator is critical for decreasing the rate of postoperative fat necrosis and minimizing perfusion-related flap complications.3 A thorough understanding of the vascular anatomy and flow characteristics of a selected perforator is essential to balance flap design and adequate flap perfusion. The angiosome concept by Taylor and Palmer has greatly contributed to our knowledge on flap perfusion.4 Saint-Cyr et al introduced in 2009 the perforasome theory and defined a perforasome as the territory perfused by a single perforator vessel of a named artery.5 The importance of finding the most suitable perforator is reflected in the large number of studies on the use of preoperative perforator mapping using imaging techniques.6 Still the relationship between the designed flap size and areas of perfusion from the selected perforator is a clinical challenge because this ratio is unknown.7 To our knowledge there are no in vivo studies that evaluate how the reduction of the number of perforators during flap harvest effects the perfusion area of a selected perforator. Indocyanine green fluorescence angiography (ICG-FA) is an invasive technique that allows for direct visualization of tissue perfusion by registration of intravascular fluorescence intensity. Infrared thermography (IRT) is a noninvasive technique that indirectly visualizes skin perfusion by measuring infrared (IR) radiation released from the skin surface. In static infrared thermography (SIRT), a single image is taken from the area of interest. In dynamic infrared thermography (DIRT), the area of interest is exposed to a mild thermal challenge, and the rate and pattern of temperature changes are recorded and analyzed. ICG-FA and IRT are well-established techniques that provide real-time assessment of skin perfusion and have been shown to provide valuable information for perforator mapping.7–12 The primary aim of this study was to evaluate the effect of perforator dissection on the perfusion area of the selected perforator in a hemi-DIEP flap by using ICG-FA and IRT intraoperatively. The secondary aim of this study was to compare the results from ICG-FA with those obtained from IRT with respect to flap perfusion.

This study aimed to investigate pulp chamber and surface temperature development using different LED light curing units (LCUs). Eight brands of LED-LCUs were tested in a laboratory bench model. The pulp chamber and surface temperature were recorded with a type T thermocouple and infrared cameras, respectively. The highest pulp chamber and surface temperature increase was 6.1±0.3°C and 20.1±1.7°C, respectively. Wide-spectrum LED-LCUs produced higher pulp chamber temperature increase at 0 mm and 2 mm but lower at 4 mm. Narrow-spectrum LED-LCUs produced higher surface temperature increase. LED-LCU featuring modulated output mode resulted in lower increase in pulp chamber temperature but higher on surface temperature. LED-LCU with light guide tip delivering an inhomogeneous beam caused higher increase in temperature on the surface and in the pulp chamber. LED-LCUs with different spectral emission, output mode and light guide tip design contributed to different temperature development in the pulp chamber and at the surface of teeth.

Background: Wound healing problems following abdominoplasty may be a result of impaired tissue perfusion. This study evaluated the impact a standard abdominoplasty may have on abdominal skin perfusion. Methods: A standard abdominoplasty was performed in 16 patients. Dynamic infrared thermography (DIRT) using a mild and a stronger cold challenge was performed pre-, intra-, and postoperatively on day 1, 2, and in week 6. The abdomen was divided into Huger’s vascular zones. A two-tailed t test was used to evaluate differences in mean temperature between zones. Statistical significance was defined as P < 0.05. Results: Two patients suffered wound healing problems. Abdominal skin perfusion showed a hyperaemic state on day 1, day 2, and week 6, postoperatively. Hotspots in zones I and II had all disappeared at the end of surgery and on day 1, except in the cranial part of zone I. Hotspots reappeared in zones I and II during day 2. A statistically significant difference between zones I and II was seen on day 1 and 2, with zone II being cooler. This difference had disappeared in week 6 for the mild cold challenge but not for the stronger cold challenge. Conclusions: A standard abdominoplasty has a significant impact on abdominal skin perfusion. The skin perfusion is a dynamic process with a gradual improvement over time. The strongest effect was seen in zone II near the lower transverse incision line, where skin perfusion was the least. Such may contribute to impaired wound healing at this site

Objective The study aimed to investigate factors contributing to heat development during light curing of a flowable bulk-fill resin-based composite (SDRTM, Lot # 602000876, Dentsply Sirona, Konstanz, Germany) (RBC). Materials and Methods Temperatures were measured with calibrated thermocouples. A multi-wave light-emitting diode (LED) light curing unit (LCU) was used (Ivoclar Vivadent, Schaan, Lichtenstein). In all experiments, the RBC was first cured (cured) for 30 s and, after 5 min of recovery time, received a second LCU irradiation (post-cured) for 30 s. The exothermic reaction was measured by calculating the Δ temperature between cured and post-cured RBC. In a cylinder-shaped polymer mold, temperature was recorded inside of RBC during curing (part 1) and light transmission through RBC during curing was investigated (part 2). Pulpal temperatures were assessed in an extracted third molar during light curing (part 3). Data were statistically analyzed using one-way ANOVA (α=0.05). Results Increased thickness of RBC led to decreased pulp chamber temperatures. Inside RBC, there was a large variation in heat development between the cured and post-cured groups (p

The year-long Philippine Sea (2010–2011) experiment (PhilSea) was an extensive deep water acoustic propagation experiment in which there were six different sources transmitting to a water column spanning a vertical line array. The six sources were placed in an array with a radius of 330 km and transmitted at frequencies in the 200–300 Hz and 140–205 Hz bands. The PhilSea frequencies are higher than previous deep water experiments in the North Pacific for which modal analyses were performed. Further, the acoustic paths sample a two-dimensional area that is rich in internal tides, waves, and eddies. The PhilSea observations are, thus, a new opportunity to observe acoustic modal variability at higher frequencies than before and in an oceanographically dynamic region. This paper focuses on mode observations around the mid-water depths. The mode observations are used to compute narrowband statistics such as transmission loss and broadband statistics such as peak pulse intensity, travel time wander, time spreads, and scintillation indices. The observations are then compared with a new hybrid broadband transport theory. The model-data comparisons show excellent agreement for modes 1–10 and minor deviations for the rest. The discrepancies in the comparisons are related to the limitations of the hybrid model and oceanographic fluctuations other than internal waves.

This study identifies general characteristics of methods to estimate the absolute range between an acoustic transmitter and a receiver in the deep ocean. The data are from three days of the PhilSea10 experiment with a single fixed transmitter depth (∼998 m) and 150 receiver depths (∼210–5388 m) of known location, and a great-circle transmitter-receiver distance of ∼510 km. The proposed ranging methods compare observed acoustic records with synthetic records computed through the HYCOM (hybrid coordinate ocean model) model. More than 8900 transmissions over 3 days characterize the statistical variation of range errors. Reliable ranging methods de-emphasize the parts of the data records least likely to be reproduced by the synthetics, which include arrival amplitudes, the later parts of the acoustic records composed of nearly horizontally launched rays (i.e., the finale), and waves that sample a narrow span of ocean depths. The ranging methods proposed normalize amplitudes, measure travel times, or reject parts of the waveforms beyond a critical time. All deliver reliable range estimates based on the time and path-averaged HYCOM model, although the final method performs best. The principles behind these methods are transportable and expected to provide reliable range estimates in different deep water settings.This study identifies general characteristics of methods to estimate the absolute range between an acoustic transmitter and a receiver in the deep ocean. The data are from three days of the PhilSea10 experiment with a single fixed transmitter depth (∼998 m) and 150 receiver depths (∼210–5388 m) of known location, and a great-circle transmitter-receiver distance of ∼510 km. The proposed ranging methods compare observed acoustic records with synthetic records computed through the HYCOM (hybrid coordinate ocean model) model. More than 8900 transmissions over 3 days characterize the statistical variation of range errors. Reliable ranging methods de-emphasize the parts of the data records least likely to be reproduced by the synthetics, which include arrival amplitudes, the later parts of the acoustic records composed of nearly horizontally launched rays (i.e., the finale), and waves that sample a narrow span of ocean depths. The ranging methods proposed normalize amplitudes, measure travel times, or reject pa...

An array of six oceanographic moorings with acoustic and environmental sensors was deployed in the central Philippine Sea from April 2010 to April 2011. The location spanned 18−23°N, 124 – 130°E in the Subtropical Countercurrent (STCC). The most prominent feature of the data set was a densely-packed eddy field with about equal numbers of cyclones and anticyclones moving westward at 6–12 km d−1. Eddies of either sign displaced the thermocline about ±50 m and had surface velocities exceeding 110 cm s−1. While warm eddies were slightly larger than cold eddies, the distance to maximum radial velocity was similar for both at about 65 km, close to the local Rossby radius of deformation. The steepness parameter U/c in the eddies ranged from 3 to 10, accompanied by relative vorticity of order 0.1–0.3 f, suggesting nonlinear, quasigeostrophic features with trapped cores rather than linear waves. This was borne out by the water mass analysis which showed high salinity, high spice North Pacific Tropical Water (NPTW) being transported westward in the warm eddy cores. The total KE and APE in eddies of both signs was about 1×1015 J with 85% of the APE and 74% of the KE located above 250 m depth. This equipartitioning of energy suggests mature eddies near equilibrium, that had been evolving for some time as they propagated into the area from the east.

A mechanism is presented by which the observed acoustic intensity is made to vary due to changes in the acoustic path that are caused by internal-tide vertical fluid displacements. The position in range and depth of large-scale caustic structure is determined by the background sound-speed profile. Internal tides cause a deformation of the background profile, changing the positions of the caustic structures-which can introduce intensity changes at a distant receiver. Gradual fades in the acoustic intensity occurring over timescales similar to those of the tides were measured during a low-frequency (284-Hz) acoustic scattering experiment in the Philippine Sea in 2009 [White et al., J. Acoust. Soc. Am. 134(4), 3347-3358 (2013)]. Parabolic equation and Hamiltonian ray-tracing calculations of acoustic propagation through a plane-wave internal tide environmental model employing sound-speed profiles taken during the experiment indicate that internal tides could cause significant gradual changes in the received intensity. Furthermore, the calculations demonstrate how large-scale perturbations to the index of refraction can result in variation in the received intensity.

Better estimates of non-aqueous phase liquid (NAPL) mass, its persistence into the future, and the potential impact of source reduction are critical needs for determining the optimal path to clean up sites impacted by NAPLs. One impediment to constraining time estimates of source depletion is the uncertainty in the rate of mass transfer between NAPLs and groundwater. In this study, an innovative field test is demonstrated for the purpose of quantifying field-scale NAPL mass transfer coefficients ( k l N ) within a source zone of a fuel-contaminated site. Initial evaluation of the test concept using a numerical model revealed that the aqueous phase concentration response to the injection of clean groundwater within a source zone was a function of NAPL mass transfer. Under rate limited conditions, NAPL dissolution together with the injection flow rate and the radial distance to monitoring points directly controlled time of travel. Concentration responses observed in the field test were consistent with the hypothetical model results allowing field-scale NAPL mass transfer coefficients to be quantified. Site models for groundwater flow and solute transport were systematically calibrated and utilized for data analysis. Results show k l N for benzene varied from 0.022 to 0.60 d − 1 . Variability in results was attributed to a highly heterogeneous horizon consisting of layered media of varying physical properties.

Purpose The American Association of Oral and Maxillofacial Surgeons appointed a task force to study the indications, safety, and clinical practice patterns of cone-beam computed tomography (CBCT) in oral and maxillofacial surgery (OMS). The charge was to review the published applications of CBCT in OMS, identify the current position of academic thought leaders in the field, and research the adoption and usage of the technology at the clinical practitioner level. Materials and Methods This study reviewed the CBCT world literature and summarized published indications for the modality. A nationwide survey of academic thought leaders and practicing oral and maxillofacial surgeons was compiled to determine how the modality is currently being used and adopted by institutions and practices. Results This report summarizes published applications of CBCT that have been vetted by the academic and practicing OMS community to define current indications. The parameters of patient safety, radiation exposure, accreditation, and legal issues are reviewed. An overview of third-party adoption of CBCT is presented. Conclusion CBCT is displacing 2-dimensional imaging in the published literature, academia, and private practice. Best practices support reading the entire scan volume with a written report defining results, patient exposure, and field of view. Issues of patient safety, ALARA (“as low as reasonably achievable”), accreditation, and the legal and regulatory environment are reviewed. Third-party patterns for reimbursements vary widely and seem to lack consistency. There is much confusion within the provider community about indications, authorizations, and payment policies. The current medical and dental indications for CBCT in the clinical practice of OMS are reviewed and an industry guideline is proposed. These guidelines offer a clear way of differentiating consensus medical indications and common dental uses for clinicians. This matrix should bring a predictable logic to third-party authorizations, billing, and predictable payments for this emerging technology in OMS.

Background: Dynamic infrared thermography (DIRT) is a noninvasive imaging technique that can provide indirect and real-time information on skin perfusion by measuring skin temperature. Although used in flap surgery, there are no reports on its value in procedures using a pedicled thoracodorsal artery perforator (TDAP) flap. The aim of this study was to assess the usefulness of DIRT in preoperative perforator mapping and in monitoring intra- and postoperative flap perfusion of pedicled TDAP flaps. Methods: This prospective study comprised 21 patients (21 flaps) scheduled for reconstructive surgery with a TDAP flap. Perforator mapping was done by DIRT, handheld unidirectional Doppler ultrasound, and computer tomography angiography. Intra- and postoperative flap perfusion was assessed by clinical signs and with the use of DIRT and handheld unidirectional Doppler ultrasound. Results: Perforator mapping with DIRT showed that first-appearing bright hotspots were always associated with arterial Doppler sounds and suitable perforators intraoperatively. Computer tomography angiography presented useful information on the thoracodorsal artery branching pattern but was less beneficial for perforator mapping. Intra- and postoperative flap monitoring with DIRT was more useful than handheld unidirectional Doppler ultrasound and clinical signs to detect early arterial and venous perfusion problems. DIRT demonstrated that TDAP flap perfusion is a dynamic process with an increase in perfusion during the first operative days. Nineteen flaps survived, of which 3 sustained distal necrosis. Two flaps were lost due to inadequate blood perfusion. Conclusion: DIRT provides valuable real-time information for perforator mapping and for monitoring TDAP flap perfusion intra- and postoperatively.

The following article, Norheim, A.J., Borud, E., Wilsgaard, T., DeWeerd, L. & Mercer, J.B. (2018). Variability in peripheral rewarming after cold stress among 255 healthy Norwegian army conscripts assessed by dynamic infrared thermography. International Journal of Circumpolar Health, 77(1), can be accessed at https://doi.org/10.1080/22423982.2018.1536250. Exposure to cold climate is an inevitable consequence of military training in Norway. Adequate peripheral microcirculation in the extremities is important to maintain temperature, and to protect against freezing cold injuries. The aim of this study was to investigate the variability in skin rewarming ability. The study subjects consisted of 260 healthy Norwegian army conscripts, following a mild cold provocation test (hands immersed in 20°C water for 1 min) using dynamic infrared thermography (DIRT). Thermal images were obtained to investigate any differences in skin rewarming ability of the hand (fingers). DIRT took place under standardised and stable study conditions. Conscripts were characterised as either slow, intermediate or rapid rewarmers. While 90% could recover, partially or completely, within 4 min to the skin temperature values before the provocation test, 10% showed a slow rewarming pattern. In the slow rewarmers, the rewarming ability was correlated with a low average temperature of the hands prior to the cooling test. The healthy young army conscripts in this study showed a large variability in their rewarming ability following a standardised mild cold provocation test.

Predictions of log-amplitude variance are compared against sample log-amplitude variances reported by White, Andrew, Mercer, Worcester, Dzieciuch, and Colosi [J. Acoust. Soc. Am. 134, 3347–3358 (2013)] for measurements acquired during the 2009 Philippine Sea experiment and associated Monte Carlo computations. The predictions here utilize the theory of Munk and Zachariasen [J. Acoust. Soc. Am. 59, 818–838 (1976)]. The scattering mechanism is the Garrett–Munk internal wave spectrum scaled by metrics based on measured environmental profiles. The transmitter was at 1000 m depth and the receivers at nominal range 107 km and depths 600–1600 m. The signal was a broadband m-sequence centered at 284 Hz. Four classes of propagation paths are examined: the first class has a single upper turning point at about 60 m depth; the second and third classes each have two upper turning points at roughly 250 m; the fourth class has three upper turning points at about 450 m. Log-amplitude variance for all paths is predicted to be 0.04–0.09, well within the regime of validity of either Born or Rytov scattering. The predictions are roughly consistent with the measured and Monte Carlo log-amplitude variances, although biased slightly low. Paths turning in the extreme upper ocean (near the mixed layer) seem to incorporate additional scattering mechanisms not included in the original theory.

While health risks from smoking cigarettes are well known, little is known about the health risks of using smokeless tobacco (ST). The aim of this study was to evaluate the effect that ST in the form of oral use of snus with nicotine and snus without nicotine has on peripheral skin blood circulation. 21 young habitual users of snus with nicotine participated in this study. Under controlled conditions the subjects were exposed to a 30 minute period of oral use of snus with nicotine (SN+) and snus without nicotine (SN-). The peripheral skin blood circulation was indirectly monitored on the hands by measuring skin temperature using infrared thermography. The skin blood circulation in the hands showed a statistical significant decrease in the SN+ experiments, while skin blood circulation was hardly effected in the SN- experiments. It is concluded that the use of smokeless tobacco in the form of oral use of snus containing nicotine causes a decrease in peripheral skin blood circulation while such an effect is not seen in snus without nicotine. This knowledge may be of use when treating patients that require adequate peripheral skin circulation or in the military when soldiers are exposed cold conditions.

Stochastic analyses were performed to examine sequential first-order monomolecular reactions at the microscopic scale and both Fickian and non-Fickian plume reactive transport at the macroscopic scale. An analytical solution was derived for the chemical master equation (CME) for a closed system of irreversible first-order monomolecular reactions. Taking a Lagrangian reference frame of particles migrating from a source, analyses show that the relative concentration of each species in the deterministic analytical solution for 1-D steady state plug flow with first-order sequential degradation is mathematically equivalent to the mean of a multinomial distribution of plume particles moving at constant velocity with sequential transformations described by transition probabilities of a discrete state, continuous-time Markov chain. In order to examine the coupling of reaction and transport terms in subdiffusive-reactive transport equations, a closed-form multispecies analytical solution also was derived for steady state advection, dispersion, and sequential first-order reaction. Using a 1-D continuous-time random walk (CTRW) embedded in Markov chains, computationally efficient Monte Carlo simulations of particle movement were performed to more fully examine effects of subdiffusive-reactive transport with an application to steady state, sequentially degrading multispecies plumes at a site in Palm, Bay, FL. The simulation results indicated that non-Fickian steady state plumes can resemble Fickian plumes because linear reactions truncate the waiting time between particle jumps, which removes lower velocity particles from the broad spectrum of velocities in highly heterogeneous media. Results show that fitting of Fickian models to plume concentration data can lead to inaccurate estimates of rate constants because of the wide distribution of travel times in highly heterogeneous media.

In the spring of 2009, broadband transmissions from a ship-suspended source with a 284-Hz center frequency were received on a moored and navigated vertical array of hydrophones over a range of 107 km in the Philippine Sea. During a 60-h period over 19,000 transmissions were carried out. The observed wavefront arrival structure reveals four distinct purely refracted acoustic paths: One with a single upper turning point near 80 m depth, two with a pair of upper turning points at a depth of roughly 300 m, and one with three upper turning points at 420 m. Individual path intensity, defined as the absolute square of the center frequency Fourier component for that arrival, was estimated over the 60-h duration and used to compute scintillation index and log-intensity variance. Monte Carlo parabolic equation simulations using internal-wave induced sound speed perturbations obeying the Garrett-Munk internal-wave energy spectrum were in agreement with measured data for the three deeper-turning paths but differed by as much as a factor of four for the near surface-interacting path.

The article of record as published may be found at https://doi.org/10.1121/1.4820882 The propagation of weakly dispersive modal pulses is investigated using data collected during the 2004 long-range ocean acoustic propagation experiment (LOAPEX). Weakly dispersive modal pulses are characterized by weak dispersion- and scattering-induced pulse broadening; such modal pulses experience minimal propagation-induced distortion and are thus well suited to communications applications. In the LOAPEX environment modes 1, 2, and 3 are approximately weakly dispersive. Using LOAPEX observations it is shown that, by extracting the energy carried by a weakly dispersive modal pulse, a transmitted communications signal can be recovered without performing channel equalization at ranges as long as 500 km; at that range a majority of mode 1 receptions have bit error rates (BERs) less than 10%, and 6.5% of mode 1 receptions have no errors. BERs are estimated for low order modes and compared with measurements of signal-to-noise ratio (SNR) and modal pulse spread. Generally, it is observed that larger modal pulse spread and lower SNR result in larger BERs. This work was supported by the Office of Naval Research, Code 322, Grant Nos. N00014-06-1-0245, N00014-08-1-0195, and N00014-11-1-0194.

During the North Pacific Acoustic Laboratory Philippine Sea 2009 experiment, towed array receptions were made from a towed source as the two ships transited from a separation of several Convergence Zones through a Closest Point of Approach at 3 km. A combination of narrowband tones and broadband pulses were transmitted covering the frequency band 79-535 Hz. The received energy arrives from two general paths-direct path and bottom bounce. Bearing-time records of the narrowband arrivals at times show a 35° spread in the angle of arrival of the bottom bounce energy. Doppler processing of the tones shows significant frequency spread of the bottom bounce energy. Two-dimensional modeling using measured bathymetry, a geoacoustic parameterization based upon the geological record, and measured sound-speed field was performed. Inclusion of the effects of seafloor roughness and surface waves shows that in-plane scattering from rough interfaces can explain much of the observed spread in the arrivals. Evidence of out-of-plane scattering does exist, however, at short ranges. The amount of out-of-plane scattering is best observed in the broadband impulse-beam response analysis, which in-plane surface roughness modeling cannot explain.

Conventional and adaptive plane-wave beamforming with simultaneous recordings by large-aperture horizontal and vertical line arrays during the 2009 Philippine Sea Engineering Test (PhilSea09) reveal the rate of occurrence and the two-dimensional arrival structure of seismic phases that couple into the deep ocean. A ship-deployed, controlled acoustic source was used to evaluate performance of the horizontal array for a range of beamformer adaptiveness levels. Ninety T-phases from unique azimuths were recorded between Yeardays 107 to 119. T-phase azimuth and S-minus-P-phase time-of-arrival range estimates were validated using United States Geological Survey seismic monitoring network data. Analysis of phases from a seismic event that occurred on Yearday 112 near the east coast of Taiwan approximately 450 km from the arrays revealed a 22° clockwise evolution of T-phase azimuth over 90 s. Two hypotheses to explain such evolution-body wave excitation of multiple sources or in-water scattering-are presented based on T-phase origin sites at the intersection of azimuthal great circle paths and ridge/coastal bathymetry. Propagation timing between the source, scattering region, and array position suggests the mechanism behind the evolution involved scattering of the T-phase from the Ryukyu Ridge and a T-phase formation/scattering location estimation error of approximately 3.2 km.

Observations of the spread of wander-corrected averaged pulses propagated over 510 km for 54 h in the Philippine Sea are compared to Monte Carlo predictions using a parabolic equation and path-integral predictions. Two simultaneous m-sequence signals are used, one centered at 200 Hz, the other at 300 Hz; both have a bandwidth of 50 Hz. The internal wave field is estimated at slightly less than unity Garrett-Munk strength. The observed spreads in all the early ray-like arrivals are very small

Source: doi: 10.1007/s00784-016-1962-5 Objectives:To investigate how heat development in the pulp chamber and coronal surface of natural teeth with and without cusps subjected to irradiance using light-emitting diode (LED)–light-curing units (LCUs) is associated with (i) irradiance, (ii) time, (iii) distance, and (iv) radiant exposure. Materials and methods:Three different LED-LCUs were used. Their irradiance was measured with a calibrated spectrometer (BlueLight Analytics Inc., Halifax, Canada). An experimental rig was constructed to control the thermal environment of the teeth. The LED-LCU tip position was accurately controlled by a gantry system. Tooth surface temperature was measured by thermography (ThermaCAM S65 HS, FLIR Systems, Wilsonville, USA) and pulp chamber temperature with a thermocouple. LED-LCU tip distance and irradiation times tested were 0, 2, and 4 mm and 10, 20, and 30 s, respectively. Ethical permission was not required for the use of extracted teeth. Results:Maximum surface and pulp chamber temperatures were recorded in tooth without cusps (58.1 °C ± 0.9 °C and 43.1 °C ± 0.9 °C, respectively). Radiant exposure explained the largest amount of variance in temperature, being more affected by time than irradiance. Conclusions:At all combinations of variables tested, repeated measurements produced consistent results indicating the reliability of the method used. Increased exposure time seems to be the factor most likely to cause tissue damage. Clinical relevance:Risk of superficial tissue damage at irradiances >1200 mW/cm2 is evident. There is a risk of pulp damage when only thin dentin is left at higher irradiances (>1200 mW/cm2). Clinicians should be aware of LED-LCU settings and possible high temperature generated.

Thermal patterns on the skin are related to skin blood perfusion. While knowledge concerning thermal distribution patterns of the face are well established, the thermal distribution patterns of the skin surface of other aspects of the head has only been investigated once previously in a study employing low resolution thermographic equipment [van Dulken, H., van Voss, S.F.C.H, 1971. The normal thermographic patterns of the human head. Acta Neurochir. 23, 247–58.] The purpose of the study was to re-examine the thermal distribution patterns of the surface of the entire head in 12 healthy bald headed male subjects (mean age 39±7.8 (SD) years) using a high definition infrared (IR) thermographic camera. The thermal distribution patterns were monitored using dynamic infrared thermography (DIRT) before, during and after a 2 min local skin cooling procedure with a pair of fans. Infrared thermal images (thermograms) were taken of the superior, anterior, lateral and posterior aspects of the head. The thermal patterns in general followed the anatomical location of the main superficial arteries and veins of the head as described in anatomy books although there were some variations, especially with regard to the forehead and top of the head (superior aspect), ranging from an asymmetrical distribution pattern to a lack of a clear thermal pattern. The thermal patterns in the left and right lateral thermograms in each individual were relatively symmetrical. During the rewarming period the helix, auricular lobule of the auricles and the nose were relatively cold. The frontal thermograms were characterized by cool nasal and cheek areas and a clear warm area surrounding the eyes, especially around the inner canthus.

Data collected during the 2004 Long-range Ocean Acoustic Propagation Experiment provide absolute intensities and travel times of acoustic pulses at ranges varying from 50 to 3200 km. In this paper a subset of these data is analyzed, focusing on the effects of seafloor reflections at the shortest transmission range of approximately 50 km. At this range bottom-reflected (BR) and surface-reflected, bottom-reflected energy interferes with refracted arrivals. For a finite vertical receiving array spanning the sound channel axis, a high mode number energy in the BR arrivals aliases into low mode numbers because of the vertical spacing between hydrophones. Therefore, knowledge of the BR paths is necessary to fully understand even low mode number processes. Acoustic modeling using the parabolic equation method shows that inclusion of range-dependent bathymetry is necessary to get an acceptable model-data fit. The bottom is modeled as a fluid layer without rigidity, without three dimensional effects, and without scattering from wavelength-scale features. Nonetheless, a good model-data fit is obtained for sub-bottom properties estimated from the data.

This article describes how dynamic infrared thermography (DIRT) can be used in autologous breast reconstruction with a deep inferior epigastric perforator flap. This noninvasive and noncontact technique for indirect monitoring of skin blood perfusion can be used in the preoperative planning and intraoperative evaluation of flap perfusion, as well as the postoperative monitoring of perfusion dynamics of DIEP flaps. DIRT provides valuable information on the perfusion physiology of perforators.

An acoustical transmitter was suspended at multiple depths to 800 m from the research vessel R/V Melville at several stations in the North Pacific in 2004. The 3-D position of the transmitter varied with time due to ship motion and subsurface currents. The transmitter 3-D position and velocity were subsequently estimated using a cable dynamics model forced by ship position, as measured by high-precision global positioning system (GPS), and subsurface currents, as measured by the onboard acoustical Doppler current profiler. These estimated positions and velocities varied in the horizontal up to 10 m from the station “center” position, and 0.5 m/s from zero, respectively. Auxiliary measurements indicate that these estimates were accurate along either horizontal coordinate to better than 2 m and 0.05 m/s, respectively. Transmitter motion dilates the apparent time base of the radiated signal, producing time-varying Doppler effects. Simulation and analysis are used to determine when the induced Doppler effect is significant, and a technique is presented that “de-dopplerizes” a received signal for arbitrary interplatform motion. One example, involving the transmitter motion solutions determined here, shows that the transmitter motion induces a root mean square (RMS) variability of roughly for a 75-Hz ranging signal on time scales of several minutes: a 41-point de-dopplerizing filter reduced this to .

Nearly two decades of low-frequency (20–500 Hz) ambient noise measurements at seven open-ocean sites in the North Pacific Ocean basin have revealed a complex pattern of long-term trends. The trends in the Northeastern Pacific Ocean show a significant decrease of almost 2 dB/decade. Along the Aleutian archipelago, the levels are either slightly increasing or remaining flat. Levels in two north central Pacific Ocean sites are essentially flat. Comparisons with very sparse measurements made over the last 5 decades suggest that the mid-latitude noise levels may have peaked in the 1990s. These measurements also show, however, that the noise level is still rising elsewhere. The mechanisms driving these trends appear to be more subtle than simply the number of merchant ships or the local wind speed. Climatically-influenced basin-scale acoustic propagation conditions may have an important role.

Background:. Wound healing problems at the donor site in free abdominal flap breast reconstruction cause significant morbidity to patients. No studies have investigated what impact the use of the internal mammary artery in free abdominal flap breast reconstruction has on abdominal skin perfusion. We hypothesized that harvesting the internal mammary vessels (IMV) has a negative effect on abdominal skin perfusion. Methods:. The abdomen and anterior thoracic wall of 17 patients scheduled for secondary free abdominal flap breast reconstruction using IMV was pre-, intra-, and postoperatively examined with dynamic infrared thermography. Qualitative and quantitative analyses of the rate and pattern of recovery in Huger’s vascular zones were made with each patient being its own control. Zone III on the side where IMV were used was numbered zone IV. The contralateral zone III was used as reference. Results:. Postoperative abdominal skin perfusion in zone IV was always significantly reduced compared with zone III (1-tailed t test, P < 0.05). The difference between zones II and III was statistically significant for day 1 and 3, but not for day 6 (2-tailed t test, P < 0.05). Skin perfusion in zones II and IV increased during consecutive postoperative days with an increase of hot spots in these areas. Conclusions:. Using the IMV in free abdominal flap breast reconstruction had a significant effect on abdominal skin perfusion and may contribute to abdominal wound healing problems. The reperfusion of the abdominal skin was a dynamic process showing an increase in perfusion in the affected areas during the postoperative days.

Observations of scattering of low-frequency sound in the ocean have focused largely on effects at long ranges, involving multiple scattering events. Fluctuations due to one and two scattering events are analyzed here, using 75-Hz broadband signals transmitted in the eastern North Pacific Ocean. The experimental geometry gives two purely refracted arrivals. The temporal and vertical scales of phase and intensity fluctuations for these two ray paths are compared with predictions based on the weak fluctuation theory of Munk and Zachariasen, which assumes internal-wave-induced sound-speed perturbations [J. Acoust. Soc. Am. 59, 818-838 (1976)]. The comparisons show that weak fluctuation theory describes the frequency and vertical-wave-number spectra of phase and intensity for the two paths reasonably well. The comparisons also show that a resonance condition exists between the local acoustic ray and the internal-wave field, as predicted by Munk and Zachariasen, such that only internal waves whose crests are parallel to the local ray path contribute to acoustic scattering. This effect leads to filtering of the acoustic spectra relative to the internal-wave spectra, such that steep rays do not acquire scattering contributions due to low-frequency internal waves.

The aim of this paper is to evaluate dynamic infrared thermography (DIRT) as a technique to assist in preoperative perforator selection and planning of free deep inferior epigastric perforator (DIEP) flaps. Twenty-seven patients, scheduled for secondary autologous breast reconstruction with either a free DIEP flap or superficial inferior epigastric artery flap, were included in this prospective clinical study. Preoperative mapping of perforators was performed with a hand-held Doppler and DIRT. A multidetector computer tomography scan was additionally carried out in the last 8 patients. In 23 patients a DIEP flap was used. The perforator as selected from DIRT was a suitable perforator in all DIEP flaps. The location and quality of the selected perforator from DIRT corresponded well with the multidetector computer tomography scan results. Preoperative perforator selection and planning of DIEP flaps is facilitated with the use of DIRT. The technique is noninvasive and easy to use.

Seasonal variations in mortality occur throughout Europe as well as in other parts of the world, such as Japan, China and the southern hemisphere1–6 with a higher death rate in the winter (excess winter deaths). Mortality from cardiovascular disease (CVD) accounts for the majority of the excess winter deaths (up to 70% in some countries), while up to about half of the remaining may be accounted for by increases in respiratory disease.3,7 The majority of deaths from CVD occur in the elderly. For example, in Norway, CVD, including ischaemic heart disease and cerebrovascular disease, accounts for about 46% of all causes of death. About 90% of all CVD-related deaths occur in people who are ≥65 years. Cold exposure related to winter mortality from ischaemic heart disease, cerebrovascular disease, respiratory disease, and all causes in warm and cold regions of Europe have been previously investigated in a large European Economic Community supported study.7 The main findings of this study was that mortality increased to a greater extent with a given fall in temperature in regions with warm winters, in populations with cooler homes, and among people who wore fewer clothes and were less active outdoors. Similar findings regarding excess winter mortality were found in a comparative study between Norway and the Republic of Ireland, two countries that were not investigated in the Eurowinter study.6,8 A comparison of these two countries is of interest since they are demographically similar with respect to CVD mortality, but have different climates. In 1993, the population of Norway and the Republic of Ireland was 4 312 000 and 3 563 000, respectively and in both countries mortality due to CVD, accounted for approximately the same percent of deaths (1985–93: Norway 45% and Ireland 47%.6 Seasonal variation in …

Receptions, from a ship-suspended source (in the band 50-100 Hz) to an ocean bottom seismometer (about 5000 m depth) and the deepest element on a vertical hydrophone array (about 750 m above the seafloor) that were acquired on the 2004 Long-Range Ocean Acoustic Propagation Experiment in the North Pacific Ocean, are described. The ranges varied from 50 to 3200 km. In addition to predicted ocean acoustic arrivals and deep shadow zone arrivals (leaking below turning points), "deep seafloor arrivals," that are dominant on the seafloor geophone but are absent or very weak on the hydrophone array, are observed. These deep seafloor arrivals are an unexplained set of arrivals in ocean acoustics possibly associated with seafloor interface waves.

Propagation of energy along the sound channel axis cannot be formally described in terms of geometrical acoustics due to repeated cusped caustics along the axis. In neighborhoods of these cusped caustics, a very complicated interference pattern is observed. Neighborhoods of interference grow with range and overlap at long ranges. This results in the formation of a complex interference wave--the axial wave--that propagates along the sound channel axis like a wave belonging to a crescendo of near-axial arrivals. The principal properties of this wave are calculated for the actual space-time configuration realized during a 2004 long-range propagation experiment conducted in the North Pacific. The experiment used M-sequences at 68.2 and 75 Hz, transmitter depths from 350 to 800 m, and ranges from 50 to 3200 km. Calculations show that the axial wave would be detectable for an optimal geometry-both transmitter and receiver at the sound channel axis--for a "smooth" range-dependent sound speed field. The addition of sound speed perturbations--induced here by simulated internal waves--randomizes the acoustic field to the extent that the axial wave becomes undetectable. These results should be typical for mid-latitude oceans with similar curvatures about the sound speed minimum.

Perfusion dynamics of 16 free DIEP flaps and 4 free SIEA flaps were studied during the first, third, and sixth postoperative day using dynamic infrared thermography (DIRT). For both flap types the zone positioned over the perforator is perfused first, followed by the adjacent ipsilateral zone, and finally the contralateral zones. Perfusion of the subdermal plexus of all zones preceded the perfusion of the subcutaneous layer of all zones. While the initial hyperemia subsided with time, the total number of hot spots increased with time. Perfusion of free DIEP and SIEA flaps during the first postoperative week is a dynamic process. The perfusion shows a stepwise progression at the level of the subdermal plexus and at the level of the subcutaneous layer each with its own time sequence and with the midline as an area of resistance for circulation.

This paper provides an overview of the experimental goals and methods of the Long-range Ocean Acoustic Propagation EXperiment (LOAPEX), which took place in the northeast Pacific Ocean between September 10, 2004 and October 10, 2004. This experiment was designed to address a number of unresolved issues in long-range, deep-water acoustic propagation including the effect of ocean fluctuations such as internal waves on acoustic signal coherence, and the scattering of low-frequency sound, in particular, scattering into the deep acoustic shadow zone. Broadband acoustic transmissions centered near 75 Hz were made from various depths to a pair of vertical hydrophone arrays covering 3500 m of the water column, and to several bottom-mounted horizontal line arrays distributed throughout the northeast Pacific Ocean Basin. Path lengths varied from 50 km to several megameters. Beamformed receptions on the horizontal arrays contained 10-20-ms tidal signals, in agreement with a tidal model. Fifteen consecutive receptions on one of the vertical line arrays with a source range of 3200 km showed the potential for incoherent averaging. Finally, shadow zone receptions were observed on an ocean bottom seismometer at a depth of 5000 m from a source at 3200-250-km range.