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This paper discusses an approach to limiting the forces applied by an industrial robot manipulator during contact without the use of external sensors. Using a time-invariant dynamic model in combination with Artificial Neural Networks, the current and torque required by each joint for a given trajectory are estimated with satisfactory precision. The estimated electrical current is compared with the actual current provided by the robot controller and stop commands are issued in the case that the exerted forces exceed a user defined threshold. This approach is implemented in the case of a low payload industrial robot and the results of the experiments show that the approach can provide good collision detection and force limiting results. [ABSTRACT FROM AUTHOR]

Marine scientists broadly agree on which major processes influence the sustainability of marine environments worldwide. Recent studies argue that such shared perceptions crucially shape scientific agendas and are subject to a confirmation bias. Based on these findings a more explicit engagement with scientists’ (shared) perceptions of global change in marine environments is called for. This paper takes stock of the shared understanding in marine science of the most pertinent, worldwide threats and impacts that currently affect marine environments. Using results from an email survey among leading academics in marine science this article explores if a shared research agenda in relation to global change in marine environments exists. The analysis demonstrates that marine scientists across disciplines are largely in agreement on some common features of global marine change. Nevertheless, the analysis also highlights where natural and social scientists diverge in their assessment. The article ends discussing what these findings imply for further improvement of interdisciplinary marine science. [ABSTRACT FROM AUTHOR]

Purpose: To investigate gender and other possible factors affecting the frequency and severity of postoperative complications in head and neck cancer free flap reconstruction. Materials and Methods: A prospective longitudinal cohort study was conducted at the Greek Anticancer Institute, St. Savvas Hospital in head and neck cancer free flap reconstruction concerning postoperative complications. We documented the patients' demographic characteristics, social habits, and perioperative factors (ie, duration of general anesthesia), reconstructive techniques, neoadjuvant radiotherapy, and physical status. Initially, univariate statistical analysis was performed to confirm which predictor variables might influence the presence and severity of complications. Next, multivariate statistical analysis was performed using logistical regression and including the factors that were statistically significant on univariate analysis. Results: From 1999 to 2009, we assessed 95 patients who had undergone surgery for head and neck cancer. Of the 95 patients, 24 were women and 71 were men. The patient age range was 20 to 87 years (mean 52, median 55). A total of 55 complications occurred in 49 patients (51.57%). Of the 55 complications, 12 (12.63%) were of major severity, 21 (22.10%) of median severity, and 22 (23.15%) of low severity. The statistical analysis revealed that the factors associated with complications were preoperative radiotherapy, female gender, and operation time. The factors associated with severe complications were female gender and alcohol use. Conclusions: Multivariate analysis of the data revealed that the factor associated with an increased incidence of postoperative complications was preoperative radiotherapy. Moreover, the variable that remained statistically significant and correlated with an increased incidence and severity of free flap reconstruction complications was female gender. Identifying the etiology of these findings is an intriguing field for additional research. [Copyright &y& Elsevier]

Background: Recurrent compression of the ulnar nerve in the cubital tunnel is a difficult problem and many solutions have been tried with variable success. Autologous vein graft wrapping is an alternative technique and it is recommended for the treatment of recalcitrant ulnar nerve compression in which 2 or more previous surgical procedures have failed to resolve the problem. Methods: Seventeen patients with recurrent cubital tunnel syndrome were treated with autologous saphenous vein wrapping. These patients had previously undergone simple decompression, decompression combined with medial epicondylectomy, anterior submuscular, or intramuscular transposition with internal neurolysis and had persistence of symptoms. Each patient underwent both subjective and objective evaluation. Results: Our clinical results on 17 patients have been encouraging. All patients reported significant pain relief, while improvements in grip strength and 2-point discrimination were also observed. There were no complications, other than transient leg swelling secondary to harvesting the saphenous vein graft from the leg. Conclusion: This technique is not technically demanding, has low donor site morbidity, and leads to pain relief and high patient satisfaction. [Copyright &y& Elsevier]

Abstract: The advent of new arthroscopic devices has led to the development of novel techniques of arthroscopic rotator cuff repair. However, failure to recognize specific technical aspects and improper application of these devices can lead to complications. We report a case of intra-articular protrusion of knotless anchors (PEEK PushLock SP, 4.5 × 18.5 mm; Arthrex, Naples, FL), used in the lateral row of a suture-bridging technique for arthroscopic rotator cuff repair. This case draws attention to the increased length of such devices when compared with traditional suture anchors, the technical aspects of proper device use, the possible patient-related factors such as implant-patient size mismatch, and the importance of additional imaging for the investigation of failure to progress postoperatively. [Copyright &y& Elsevier]

Purpose: Radiofrequency (RF) probes used in wrist arthroscopy may raise joint fluid temperature, increasing the risk of capsular and ligamentous damage. The purposes of the current study were to measure joint fluid temperature during wrist arthroscopy with the use of RF probes, and to determine whether using an outlet portal will reduce the maximum temperature. Methods: We performed wrist arthroscopy on 8 cadaveric arms. Ablation and coagulation cycles using RF probe were performed at documented locations within the joint. This was done for 60-second intervals on both the radial and ulnar side of the wrist, to mimic clinical practice. We used 4 fiberoptic phosphorescent probes to measure temperature (radial, ulnar, inflow-tube, and outflow-tube probes) and measured joint fluid temperature with and without outflow. Results: There was a significant difference between wrists with and without outflow when examining maximum ablation temperatures (p < .002). All specimens showed higher maximum and average ablation temperatures without outflow. Maximum joint temperatures, greater than 60°C, were observed in only no-outflow conditions. Conclusions: In performing RF ablation during wrist arthroscopy, the use of an outlet portal reduces the joint fluid temperature. Without an outlet portal, maximum temperatures can exceed desirable levels when using ablation; such temperatures have the potential to damage adjacent tissues. It is useful to maintain adequate outflow when using the radiofrequency probes during wrist arthroscopy. [Copyright &y& Elsevier]

Purpose: Trapezium excision with ligament reconstruction and tendon interposition has proved to be highly effective in the treatment of thumb carpometacarpal joint arthritis. Donor-site morbidity from autograft harvest can be avoided by using an allograft. We report the outcomes after suspension and interposition arthroplasty using an acellular dermal allograft (GraftJacket; Wright Medical Technology, Inc., Arlington, TN) for thumb carpometacarpal arthritis. Methods: Eighty-nine patients (100 thumbs) had surgery for thumb carpometacarpal arthritis using acellular dermal allograft instead of flexor carpi radialis tendon autograft. Evaluation of the results was performed for 82 thumbs with adequate data. Each patient was followed up for a minimum of 12 months (average, 30 months). Pain levels, grip strength, key pinch strength, range of motion, and radiographic measurements were performed. Results: Between the preoperative and final follow-up measurements, patient pain levels (on a visual analog scale) were significantly reduced, from 6.2 to 0.7. Comparisons between preoperative and postoperative strength measurements showed an average 16% increase in grip strength and 19% increase in key pinch strength. No differences were found for radial abduction and palmar abduction data, respectively. Comparison with the preoperative x-rays showed the thumb metacarpal had subsided 31% of the arthroplasty space. No patient experienced a foreign body reaction or suffered an infection in our series. Conclusions: Trapeziectomy with suspension and interposition arthroplasty using an acellular dermal allograft is highly effective for the treatment of thumb carpometacarpal arthritis. This procedure provides a safe and effective alternative to autograft for both ligament reconstruction and tendon interposition and eliminates the potential morbidity of autograft harvest. Type of study/level of evidence: Therapeutic IV. [Copyright &y& Elsevier]

The purpose of this article is to provide an update and analyze current management, treatment options, and outcomes of elbow arthritis. This article focuses on studies that have been published in the past 5 years. Nonoperative management may provide symptomatic relief in the early stages of the disease process for most patients. Surgical treatment is guided by disease etiology and severity, patient age, and functional demands. Arthroscopic or open synovectomy, debridement arthroplasty, and interposition arthroplasty are generally recommended for the young and active patient population, whereas for low-demand and elderly patients with end-stage painful arthritis, total elbow arthroplasty is considered a more suitable surgical option. Advances in arthroscopic techniques and implant design have led to substantial improvements in treatment of elbow arthritis. [Copyright &y& Elsevier]

We present a comprehensive analysis of the seasonal variability of the vertical profiles of the optical and geometrical properties of Saharan dust aerosols, observed in the height region between 1000 and 6000 m, over the city of Athens, Greece, from February 2000 to December 2016. These observations were performed by a multi-wavelength (355-387-532-1064 nm) Raman lidar system under cloud-free conditions. The statistical analysis (using aerosol monthly mean values) is based on nighttime vertical Raman measurements of range-resolved aerosol optical properties (backscatter and extinction coefficients, lidar ratio, Ångström exponent) at 355 nm (57 dust events during more than 80 measurement hours). We found that the number of dust events was highest in spring, summer, and early autumn periods and that during spring the dust layers were moved at higher altitudes (∼4500 m) than in other seasons. The number of the forecasted dusty days (on monthly basis) by the BSC-DREAM8b model compared to those of the performed lidar measurements were found to have a quite strong correlation (R 2  = 0.81), with a maximum occurrence predicted for the spring season. In the worst case scenario, at least 50% of the model-forecasted dust events can be observed by lidar under cloudless skies over Athens. For the sampled dust plumes we found mean lidar ratios of 52 ± 13 sr at 355 nm in the height range 2000–4000 m a.s.l. Moreover, the dust layers had a mean thickness of 2497 ± 1026 m and a center of mass of 2699 ± 1017 m. An analysis performed regarding the air mass back-trajectories arriving over Athens revealed two main clusters: one pathway from south-west to north-east, with dust emission areas in Tunisia, Algeria and Libya and a second one from south, across the Mediterranean Sea with emission areas over Libya and the remaining part of Algeria and Tunisia. This clustering enabled us to differentiate between the aerosol optical properties between the two clusters, based on their residence time over the Saharan region, the European continent and the Mediterranean Sea. We finally concluded that even if the dust source regions are about the same, the aging and mixing processes of these air masses, passing over different areas, might have an impact on the aerosol optical properties. [ABSTRACT FROM AUTHOR]

Abstract: The influence of Saharan dust on the air quality of Southern European big cities became a priority during the last decade. The present study reports results on PM10 monitored at an urban site at 14m above ground level during an intense Saharan dust transport event. The elemental composition was determined by Energy Dispersive X-ray Fluorescence Spectrometry (EDXRF) for 12 elements: Si, Al, Fe, K, Ca, Mg, Ti, S, Ni, Cu, Zn and Mn. PM10 concentrations exceeded the EU limit (50μg/m3) several times during the sampling period. Simultaneous maxima have been observed for the elements of crustal origin. The concentrations of all the elements presented a common maximum, corresponding to the date where the atmosphere was heavily charged with particulate matter permanently for an interval of about 10h. Sulfur and heavy metal concentrations were also associated to local emissions. Mineral dust represented the largest fraction of PM10 reaching 79%. Seven days back trajectories have shown that the air masses arriving over Athens, originated from Western Sahara. Scanning Electron Microscopy coupled with Energy Dispersive X-ray analysis (SEM-EDX) revealed that particle agglomerates were abundant, most of them having sizes <2μm. Aluminosilicates were predominant in dust particles also rich in calcium which was distributed between calcite, dolomite, gypsum and Ca–Si particles. These results were consistent with the origin of the dust particles and the elemental composition results. Sulfur and heavy metals were associated to very fine particles <1μm. [Copyright &y& Elsevier]

Abstract: The vertical extension and the optical properties of aged ash layers advected from the Eyjafjallajökull volcanic eruption over the Eastern Mediterranean (Greece and Turkey) are presented for the period May 10–21, 2010. Raman lidar observations performed at three stations of EARLINET (Athens, Thessaloniki and Istanbul), provided clear ash signatures within certain layers, although ash was sometimes mixed with mineral dust advected from the Saharan region. AERONET columnar measurements did not indicate the presence of ash over the area for that period, although they did for the dust particles. This was further investigated and confirmed by simulations of the ash trajectories by the FLEXPART model and the BSC-DREAM8b dust model. Good agreement was found between simulated and observed geometrical characteristics of the ash and dust layers, respectively. Ash particles were observed over the lidar stations after 6–7-days transport from the volcanic source at height ranges between approximately 1.5 and 6 km. Mean ash particle layer thickness ranged between 1.5 and 2.5 km and the corresponding aerosol optical depth (AOD) was of the order of 0.12–0.06 at 355 nm and of 0.04–0.05 at 532 nm. Inside the ash layers, the lidar ratios (LR) ranged between 55 and 67 sr at 355 nm and 76–89 sr at 532 nm, while the particle linear depolarization ratio ranged between 10 and 25%. [Copyright &y& Elsevier]

Abstract: At the end of August 2009, wild fires ravaged the north-eastern fringes of Athens destroying invaluable forest wealth of the Greek capital. In this work, the impact of these fires on the air quality of Athens and surface radiation levels is examined. Satellite imagery, smoke dispersion modeling and meteorological data confirm the advection of smoke under cloud-free conditions over the city of Athens. Lidar measurements showed that the smoke plume dispersed in the free troposphere and lofted over the city reaching heights between 2 and 4 km. Ground-based sunphotometric measurements showed extreme aerosol optical depth, reaching nearly 6 in the UV wavelength range, accompanied by a reduction up to 70% of solar irradiance at ground. The intensive aerosol optical properties, namely the Ångström exponent, the lidar ratio, and the single scattering albedo, showed typical values for highly absorbing fresh smoke particles. In-situ air quality measurements revealed the impact of the smoke plume down to the surface with a slight delay on both the particulate and gaseous phase. Surface aerosols increase was encountered mainly in the fine mode with prominent elevation of OC and EC levels. Photochemical processes, studied via NO x titration of O3, were also shown to be different compared to typical urban photochemistry. [ABSTRACT FROM AUTHOR]

In this paper we extract the aerosol microphysical properties for a collection of mineral dust cases measured by multi-wavelength depolarization Raman lidar systems located at the National Technical University of Athens (NTUA, Athens, Greece) and the Andalusian Institute for Earth System Research (IISTA-CEAMA, Granada, Spain). The lidar-based retrievals were carried out with the Spheroidal Inversion eXperiments software tool (SphInX) developed at the University of Potsdam (Germany). The software uses regularized inversion of a two-dimensional enhancement of the Mie model based on the spheroid-particle approximation with the aspect ratio determining the particle shape. The selection of the cases was based on the transport time from the source regions to the measuring sites. The aerosol optical depth as measured by AERONET ranged from 0.27 to 0.54 (at 500 nm) depending on the intensity of each event. Our analysis showed the hourly mean particle linear depolarization ratio and particle lidar ratio values at 532 nm ranging from 11 to 34% and from 42 to 79 sr respectively, depending on the mixing status, the corresponding air mass pathways and their transport time. Cases with shorter transport time showed good agreement in terms of the optical and SphInX-retrieved microphysical properties between Athens and Granada providing a complex refractive index value equal to 1.4 + 0.004i. On the other hand, the results for cases with higher transport time deviated from the aforementioned ones as well as from each other, providing, in particular, an imaginary part of the refractive index ranging from 0.002 to 0.005. Reconstructions of two-dimensional shape-size distributions for each selected layer showed that the dominant effective particle shape was prolate with diverse spherical contributions. The retrieved volume concentrations reflect overall the intensity of the episodes. • Inversion of a two-dimensional enhancement of the Mie model based on the spheroid-particle approximation. • Reconstructions of two-dimensional shape-size distributions for selected layers. • Focus on short range (pure) to long range (mixture) dust processes. • Mean δ aer and LR values at 532 nm range from 11 to 34% and from 42 to 79 sr respectively, depending on the mixing state. • AOD as measured by AERONET ranged from 0.27 to 0.54 (at 500 nm) depending on the intensity of each event. [ABSTRACT FROM AUTHOR]