Evaluation of AIS3+ car occupant injuries using deterministic and probabilistic methods in frontal crashes.

Computational modelling was used to assess the capability of a deterministic and a probabilistic method to predict the incidence of AIS3+ injuries in passenger car occupants by comparing the predictions of the methods to the actual injuries observed in real-world crashes. The likelihood of sustaining an injury was first calculated using a computer model for a selected set of injury criteria in different impact conditions based on real-world crashes; AIS3+ injuries were then predicted using each method separately. Regardless of the method, the number of serious injuries was over-predicted. It was also noted that the used injury criteria suggested the occurrence of specific injuries that were not observed in the real world. Although both methods are susceptible to be adapted to improve their predictions, the question of the suitability of using some of the most commonly accepted injury criteria used with crash test dummies for injury assessment with human body models deserves further research.

Pyelo-hepatic abscess caused by staghorn stone infection: a case report.

BACKGROUND: The most common source of pyogenic liver abscess is biliary tract infection. Other less common routes include the spread of bacteria from distant foci. However, direct extension of a perinephric infection focus to the liver is extremely rare. CASE REPORT: The patient was a non-diabetic, immunocompetent, 29-year-old woman of mixed race ancestry with a history of recurrent urinary tract infections who was referred to our hospital because of an ultrasound-detected liver abscess. She was initially treated with metronidazole for 20 days at the referring institution for suspected amebic abscess without improvement. On admission to our center, she was febrile and complained of a dull right upper quadrant pain. A POCUS ultrasound suggested a pyogenic abscess, probably from a staghorn calculus infection. She received meroperem and amikacin for 22 and 10 days, respectively. Repeat hemocultures showed no growth, but urine cultures were positive for Proteus sp. Complete remission of clinical and imaging findings was observed under antibiotics. The patient was referred to the urology outpatient clinic to discuss the option of radical nephrectomy. CONCLUSION : This case underlines the high morbidity of staghorn calculi.

Spontaneous Pneumomediastinum in a 15-Year-Old Adolescent After Unintended Overexposure to Paint Diluent (Thinner) Fumes: First Reported Case.

Spontaneous pneumomediastinum (SPM) is the presence of air in the mediastinal interstices in the absence of any surgical or medical procedure, chest trauma, or mechanical ventilation. SPM can occur during vigorous Valsalva maneuvers, such as weight lifting, coughing fits, hyperemesis gravidarum, and so on, or during inhalation of illicit substances or toxic agents, as a result of an abrupt increase in pressure in the tracheal tree. Preexisting underlying lung disease may be a contributing factor. In the present case, we report for the first time an SPM due to accidental overexposure to paint thinner in a 15-year-old male from a low-income rural family. He was offered a job painting the inside of a house, which he accepted to earn some money for the family household. However, due to his inexperience, he overdosed on a can of paint with thinner. About 2 h after starting work, he began to feel increasingly severe chest pain and had to be rushed to the local level one basic hospital by his parents. Physical examination revealed subcutaneous emphysema over the supraclavicular area and crackles in the precordial area. Chest radiographs showed a pneumomediastinum. In retrospect, the patient denied coughing or sneezing attacks after exposure. He was transferred to a regional tertiary hospital for further diagnostic evaluation to rule out airway/esophageal perforation. Chest computed tomography confirmed underlying SPM and subcutaneous emphysema. The oesophagogram and bronchoscopy were unremarkable. SPM, possibly secondary to overexposure to thinner vapors, a hydrocarbon-based compound, was the final diagnosis. The patient was discharged asymptomatic on day 5.

Influence of needle design and irrigation depth in the presence of vapor lock: A computational fluid dynamics analysis in human oval roots with apical ramification.

This paper aims to study the removal of a vapor lock located in the apical ramification of an oval distal root of a human mandibular molar, simulating different needles and irrigation depths with computational fluid dynamic. A geometric reconstruction of the micro-CT of the molar shaped up to a WaveOne Gold Medium instrument was used. A vapor lock located in the apical 2 mm was incorporated. Geometries with positive pressure needles (side-vented [SV], flat or front-vented [FV] and notched [N]) and the EndoVac microcannula (MiC) were created to run the simulations. Irrigation key parameters (flow pattern, irrigant velocity, apical pressure, wall shear stress) and vapor lock removal were compared among the different simulations. Each needle behaved differently that is, FV removed the vapor lock from one ramification and had the highest apical pressure and shear stress values; SV removed the vapor lock in the main root canal but not in the ramification and reached the lowest apical pressure from the positive pressure needles; N was not able to completely remove the vapor lock and showed low apical pressure and shear stress; MiC removed the vapor lock from one ramification, had negative apical pressure and the lowest maximum shear stress. The main conclusion is that none of the needles showed complete removal of vapor lock. MiC, N, and FV were able to partially remove the vapor lock from one out of the three ramifications. However, SV needle was the only simulation that showed high shear stress with low apical pressure.

Evaluation of the ergonomic sitting position adopted by dental students while using dental simulators.

Background/purpose: Ergonomics in dentistry encourages the work to be in an organized manner, where a dentist achieves highest performance with maximum comfort and minimum physical and psychological effort. The purpose of this study was to evaluate the ergonomic sitting position of dental students from third, fourth and fifth year undergraduate programs while they prepared teeth 46 and 27 as Black Class I preparation for amalgam using dental simulators. Materials and methods: Ten students were randomly selected from each year for this study. Photos and videos were taken from them to record their sitting position as they performed a Black Class I amalgam preparation in Nissin simulators. Results: It was found that more students had a poor ergonomic sitting position while working in mandibular area (60%, torso and neck angle; 53% knee-angle; 50% elbow-angle). When comparing the average score between maxilla and mandible within students of the same year, fourth year students had a significant difference in their average, with a better performance in maxilla (P ≤ 0.01). They also showed better performance in maxillary area compared to fifth-year students (P ≤ 0.008). The main reasons that the students presented as justification for their bad posture were little work time, lack of knowledge, not knowing how to use indirect vision, and poor comfort. Conclusion: Every undergraduate year had a compromised sitting position, with the exception of fourth-year students when working in maxillary area. No correlation between undergraduate year and performance was found.

Acute hemodialysis catheter follows the path of least resistance.

The placement of large bore double-lumen catheters for hemodialysis (HD) is one of the most frequent procedures performed in HD patients. However, these procedures are associated with complications, the most common being catheter malposition. In this context, catheter deviation to the left superior intercostal vein (LISV) is a very uncommon malposition, which must be differentiated from intrathoracic extravascular catheter lodgment. We report a case of an adult male patient on hemodialysis who presented with a thrombosed arteriovenous fistula and requiring urgent HD. His past medical history included hemophilia, allergy to contrast media, and multiple previous central vein catheterizations. A non-tunneled HD catheter was placed without any difficulty in the left internal jugular vein. However, the arterial lumen failed to pull any blood with free flow in the venous lumen. A chest X-ray revealed a surprising finding. The malpositioned catheter was removed successfully without any complications.

Myiasis in a Neglected Elderly: Urgent Action Needed in South America.

Background: Myiasis is an infestation by fly larvae. Some species exclusively affect humans, contaminating wounds, mucous membranes, and other tissues. It is a disease with marked socioeconomic connotations. Case Presentation: The current case involves a 95-year-old woman, an inhabitant of the Andean region of Ecuador with a history of resection of basal cell carcinoma in the left zygomatic region and a diagnosis of chronic leukemia. The surgical wound was secondarily infested with Cochliomyia hominivorax fly larvae and the patient was readmitted to the hospital to treat this complication. A marked clinical improvement was observed after surgical debridement, removal of larvae and administration of ivermectin and antibiotics. Conclusion: The determinants of this infestation were advanced age, neglect, and destitution in a patient with an open wound on the face after resection of a basal cell carcinoma. This case illustrates the appalling reality of the marginalized and excluded population of South America. Also of concern is the expansion of myiasis-producing fly populations to areas outside their natural humid and warm habitat. South American governments are called upon to act jointly and effectively against this ominous disease.

A new species of Pseudophanerotoma (Hymenoptera, Braconidae) from Nayarit, Mexico.

Parasitoid wasps are known to be among the most abundant and species-rich on Earth and thus considered an ecologically important group of arthropods. Braconid wasps play a key role in regulating the populations of Lepidoptera, Coleoptera, and Diptera. However, the biology and taxonomy of numerous parasitoid species remain poorly known. In Mexico, only 17 species of the subfamily Cheloninae have been described. A new species of Pseudophanerotoma Zettel, 1990 (Hymenoptera, Braconidae), P.huichol sp. nov., is described from Nayarit, Mexico. The tortricid moth Cryptaspasmaperseana Gilligan & Brown, 2011 is reported as the host of this parasitoid wasp. Detailed taxonomic and barcoding information are provided.

CFD analysis on the effect of combining positive and negative pressure during the irrigation of artificial isthmuses.

Fluid dynamics generated by irrigation needles have not been deeply analyzed in root canal irregularities such as apical ramifications or isthmus where the cleaning capacity of irrigants might be compromised and hence the treatment outcome. The goal of this study was to compare the key irrigation parameters (flow pattern, irrigant velocity, apical pressure, and shear stress) between two irrigation needles and the additional effect of aspiration cannulas through computational fluid dynamics. A 3D-model consisting of two canals linked by an isthmus was modeled. The abovementioned needles irrigated the primary canal, whereas an aspiration cannula was located inside the secondary canal. Both the geometry definition and spatial discretization were carried out with ANSYS 16.2, through which six different simulations were performed: lateral exit (LE) needle, frontal exit (FE) needle, LE and cannula in crown (LEC), FE and cannula in crown (FEC), LE and cannula in middle third (LEM), FE and cannula in middle third (FEM). FE and FEM showed that the irrigation flow only passes through the isthmus in the most apical section (maximum irrigant velocity / shear stress = 8.44 m/s / 1628.44 Pa and 8.63 m/s / 1185.69 Pa, respectively). However, the remaining simulations showed the irrigation flow passing through the isthmus twice, through the most apical section first and through the upper part of the isthmus later (maximum irrigant velocity / shear stress = 8.48 m/s / 1298.24 Pa (LE), 8.61 m/s / 1261.36 Pa (LEM), 8.61 m/s / 1355.24 Pa (LEC), 8.59 m/s / 1256.87 Pa (FEC)). Furthermore, the highest velocity values were detected when aspiration cannulas were added.

Imported Human West Nile Virus Lineage 2 Infection in Spain: Neurological and Gastrointestinal Complications.

We report the first human case of West Nile virus (WNV) lineage 2 infection imported to Spain by a traveler returning from Romania. Serum, cerebrospinal fluid and urine samples were analyzed and West Nile virus infection was identified by PCR and serological tests. The patient developed fever, diarrhea and neurological symptoms, accompanied by mild pancreatitis, described previously in very few cases as a complication of WNV infection and by alithiasic cholecystitis. Viral RNA was detected in urine until 30 days after the onset of symptoms and neutralizing antibodies were detected at very low titers. The phylogenetic analysis in a fragment of the NS5 gene of the virus showed a homology with sequences from WNV lineage 2 belonging to the monophyletic Central/Southern European group.

Positive and negative pressure irrigation in oval root canals with apical ramifications: a computational fluid dynamics evaluation in micro-CT scanned real teeth.

AIM: To compare using computational fluid dynamics (CFD) the flow pattern, irrigant velocity, apical pressure and shear stress produced by negative (MiC) and positive pressure with different types of needles (side-vented (SV), front-vented (FV) and notched (N)) at two insertion depths in the apical ramification of oval root canals. METHODOLOGY: The micro-CT of a mandibular molar with an oval root canal with an apical ramification was used for computational analysis after preparation and geometric reconstruction. Geometries with the needles in two positions (1 and 3 mm from WL) were created to run the simulations. Key parameters of irrigation were displayed with CFD and compared. RESULTS: The penetration depth of the needle in the root canal strongly influenced shear stress and apical pressure. The three needles revealed that the highest shear stress, velocity and apical pressure were 1 mm from the WL and generated medium velocities. In N simulations, the fluid flow did not reach the apical ramification and the lowest shear stress values for positive pressure needles were found. The predominant axial component for FV revealed a different pattern of irrigation with high shear stress values and higher apical pressures than those exerted by other needles. SV simulations had generalized fluid flow in most of the main canal, the highest shear stress values and lower apical pressure than the threshold determined for risk of extrusion. MiC was associated with low velocity, shear stress and apical pressure. CONCLUSION: The SV needle demonstrated a combination of low positive pressure and high shear stress; while N had the lowest shear stress and FV the highest apical pressure. MiC generated fluid flow in part of the apical ramification with negative apical pressure values but low shear stress and velocity.

Oscillatory trajectory of an optical beam propagating in free space.

We describe the experimental observation of nonrectilinear trajectories of a nearly Gaussian light beam propagating in free space, after reflecting from a glass-air interface near critical incidence. The angular-dependent reflection coefficients modulate the incident beam's angular spectrum, shifting the reflected beam from the rectilinear path predicted by geometrical optics. The beam trajectory shows strong dependence on the angle of incidence, changing from rectilinear to oscillatory within 0.07°. Our experimental results are in good agreement with theoretical predictions for the trajectories followed by the intensity peak of the reflected beam.

Direct measurement of the composite Goos-Hänchen shift of an optical beam.

We experimentally study the Goos-Hänchen shift of a focused Gaussian optical beam in the critical region of incidence. We directly measure the beam's shift evaluated from the displacement of the location of the beam's intensity peak and its centroid by a novel image analysis method. We verify that the evaluation method has a dramatic impact on the physics of beam shift phenomena. The influence of wavelength, beam waist, and propagation distance on the beam shift is studied. Our experimental results confirm recent theoretical predictions about the composite Goos-Hänchen shift, including the observation of negative shifts of the beam's intensity peak.

Teaching childbirth with high-fidelity simulation. Is it better observing the scenario during the briefing session?

The design of optimal courses for obstetric undergraduate teaching is a relevant question. This study evaluates two different designs of simulator-based learning activity on childbirth with regard to respect to the patient, obstetric manoeuvres, interpretation of cardiotocography tracings (CTG) and infection prevention. This randomised experimental study which differs in the content of their briefing sessions consisted of two groups of undergraduate students, who performed two simulator-based learning activities on childbirth. The first briefing session included the observations of a properly performed scenario according to Spanish clinical practice guidelines on care in normal childbirth by the teachers whereas the second group did not include the observations of a properly performed scenario, and the students observed it only after the simulation process. The group that observed a properly performed scenario after the simulation obtained worse grades during the simulation, but better grades during the debriefing and evaluation. Simulator use in childbirth may be more fruitful when the medical students observe correct performance at the completion of the scenario compared to that at the start of the scenario. Impact statement What is already known on this subject? There is a scarcity of literature about the design of optimal high-fidelity simulation training in childbirth. It is known that preparing simulator-based learning activities is a complex process. Simulator-based learning includes the following steps: briefing, simulation, debriefing and evaluation. The most important part of high-fidelity simulations is the debriefing. A good briefing and simulation are of high relevance in order to have a fruitful debriefing session. What do the results of this study add? Our study describes a full simulator-based learning activity on childbirth that can be reproduced in similar facilities. The findings of this study add that high-fidelity simulation training in childbirth is favoured by a short briefing session and an abrupt start to the scenario, rather than a long briefing session that includes direct instruction in the scenario. What are the implications of these findings for clinical practice and/or further research? The findings of this study reveal what to include in the briefing of simulator-based learning activities on childbirth. These findings have implications in medical teaching and in medical practice.

Side-lobe level reduction in bio-inspired optical phased-array antennas.

Phased arrays are expected to play a critical role in visible and infrared wireless systems. Their improved performance compared to single element antennas finds uses in communications, imaging, and sensing. However, fabrication of photonic antennas and their feeding network require long element separation, leading to the appearance of secondary radiation lobes and, consequently, crosstalk and interference. In this work, we experimentally show that by arranging the elements according to the Fermat's spiral, the side lobe level (SLL) can be reduced. This reduction is proved in a CMOS-compatible 8-element array, revealing a SLL decrement of 0.9 dB. Arrays with larger numbers of elements and inter-element spacing are demonstrated through an spatial light modulator (SLM) and an SLL drop of 6.9 dB is measured for a 64-element array. The reduced SLL, consequently, makes the proposed approach a promising candidate for applications in which antenna gain, power loss, or information security are key requirements.

Modeling Mechanochemical Reaction Mechanisms.

The mechanochemical reaction between copper and dimethyl disulfide is studied under well-controlled conditions in ultrahigh vacuum (UHV). Reaction is initiated by fast S-S bond scission to form adsorbed methyl thiolate species, and the reaction kinetics are reproduced by two subsequent elementary mechanochemical reaction steps, namely a mechanochemical decomposition of methyl thiolate to deposit sulfur on the surface and evolve small, gas-phase hydrocarbons, and sliding-induced oxidation of the copper by sulfur that regenerates vacant reaction sites. The steady-state reaction kinetics are monitored in situ from the variation in the friction force as the reaction proceeds and modeled using the elementary-step reaction rate constants found for monolayer adsorbates. The analysis yields excellent agreement between the experiment and the kinetic model, as well as correctly predicting the total amount of subsurface sulfur in the film measured using Auger spectroscopy and the sulfur depth distribution measured by angle-resolved X-ray photoelectron spectroscopy.

Weak measurement of the composite Goos-Hänchen shift in the critical region.

By using a weak measurement technique, we investigated the interplay between the angular and the lateral Goos-Hänchen shift of a focused He-Ne laser beam for incidence near the critical angle. We verified that this interplay dramatically affects the composite Goos-Hänchen shift of the propagated beam. The experimental results confirm theoretical predictions that recently appeared in the literature.

Adsorption of hydrogen on the surface and sub-surface of Cu(111).

The interaction of atomic hydrogen with the Cu(111) surface was studied by a combined experimental-theoretical approach, using infrared reflection absorption spectroscopy, temperature programmed desorption, and density functional theory (DFT). Adsorption of atomic hydrogen at 160 K is characterized by an anti-absorption mode at 754 cm(-1) and a broadband absorption in the IRRA spectra, related to adsorption of hydrogen on three-fold hollow surface sites and sub-surface sites, and the appearance of a sharp vibrational band at 1151 cm(-1) at high coverage, which is also associated with hydrogen adsorption on the surface. Annealing the hydrogen covered surface up to 200 K results in the disappearance of this vibrational band. Thermal desorption is characterized by a single feature at ∼295 K, with the leading edge at ∼250 K. The disappearance of the sharp Cu-H vibrational band suggests that with increasing temperature the surface hydrogen migrates to sub-surface sites prior to desorption from the surface. The presence of sub-surface hydrogen after annealing to 200 K is further demonstrated by using CO as a surface probe. Changes in the Cu-H vibration intensity are observed when cooling the adsorbed hydrogen at 180 K to 110 K, implying the migration of hydrogen. DFT calculations show that the most stable position for hydrogen adsorption on Cu(111) is on hollow surface sites, but that hydrogen can be trapped in the second sub-surface layer.