The Association between COVID-19 and Changes in Opioid Prescribing Patterns and Opioid-Related Overdoses: A Retrospective Cohort Study.

Background: Recent data suggest that restrictions related to COVID-19 resulted in changes in the prescribing patterns of opioids. Aims: We sought to analyze Ontario health data for changes in frequencies among new and continuing users for the following opioid prescription characteristics: the type of opioid, the average daily dose, and the prescriber's specialty. Methods: Utilizing data on the Ontario Health Data Platform, we defined two 149-day windows as "before" and "after" based on the initial COVID-19 provincial lockdown. A total of 882,268 individuals met our inclusion criteria and were classified as either "new" or "continuing" users. Chi-square tests and Fisher's exact tests were applied for each level of our primary outcomes to determine whether there were significant changes in prescription proportions before and after the lockdown. Results: A decline of 28% was observed for the number of new users after the lockdown. Statistically significant changes were observed for new users across almost all opioid prescription characteristics between the before and after windows. The proportion of new users who received at least one dispensing event from a pharmacist increased by 26.32%, whereas continuing users increased by 378.61%. There were no statistically significant shifts in opioid prescriptions among individuals with a reported toxicity event during the study period. Conclusions: In terms of opioid prescribing patterns, new users experienced greater change following the onset of the pandemic lockdown than continuing users. Our findings potentially showcase the unintended impacts that COVID-19-related restrictions had on non-COVID-19-related health services, which can inform future policy decisions.

Contexte: Des données récentes indiquent que les restrictions liées à la COVID-19 ont entrainé des changements dans la prescription des opioïdes.Objectifs: Nous avons cherché à analyser les données sur la santé de l'Ontario pour déceler les changements de fréquence chez les nouveaux utilisateurs et les utilisateurs prévalents pour les caractéristiques de prescription d'opioïdes suivantes : le type d'opioïde, la dose quotidienne moyenne, et la spécialité du prescripteur.Méthodes: En utilisant les données de la plateforme de données sur la santé de l'Ontario, nous avons défini deux fenêtres de 149 jours comme suit : « avant ¼ et « après ¼ le confinement provincial initial de la COVID-19. Un total de 882 268 personnes ont répondu à nos critères d'inclusion et ont été classées comme « nouveaux utilisateurs ¼ ou « utilisateurs prévalents ¼. Des tests de chi-carré et des tests exacts de Fisher ont été appliqués pour chaque niveau de nos résultats primaires afin de déterminer s'il y avait eu des changements importants dans les proportions prescrites avant et après le confinement.Résultats: Une baisse de 28 % a été observée pour le nombre de nouveaux utilisateurs après le confinement.Des changements statistiquement significatifs ont été observés pour les nouveaux utilisateurs pour presque toutes les caractéristiques de prescriptions d'opioïdes entre les fenêtres avant et après. La proportion de nouveaux utilisateurs ayant eu au moins une prescription remplie par un pharmacien a augmenté de 26,32 %, tandis que le nombre d'utilisateurs prévalents a augmenté de 378,61 %. Il n'y a pas eu de changements statistiquement significatifs dans les prescriptions d'opioïdes parmi les personnes ayant déclaré un évènement de ⁠toxicité au cours de la période d'étude.Conclusions: En matière de modèles de prescription d'opioïdes, les nouveaux utilisateurs ont connu un changement plus important après le début du confinement de la pandémie que les utilisateurs prévalents. Nos résultats démontrent possiblement les répercussions inattendues des restrictions liées à la COVID-19 sur les services de santé non liés à la COVID-19, ce qui pourrait éclairer les décisions politiques futures.

Size and Strain of Zinc Sulfide Nanoparticles Altered by Interaction with Organic Molecules.

Nanosized zinc sulfides (nano-ZnS) have size-dependent and tunable physical and chemical properties that make them useful for a variety of technological applications. For example, structural changes, especially caused by strain, are pronounced in nano-ZnS < 5 nm in size, the size range typical of incidental nano-ZnS that form in the environment. Previous research has shown how natural organic matter impacts the physical properties of nano-ZnS but was mostly focused on their aggregation state. However, the specific organic molecules and the type of functional groups that are most important for controlling the nano-ZnS size and strain remain unclear. This study examined the size-dependent strain of nano-ZnS synthesized in the presence of serine, cysteine, glutathione, histidine, and acetate. Synchrotron total scattering pair distribution function analysis was used to determine the average crystallite size and strain. Among the different organic molecules tested, those containing a thiol group were shown to affect the particle size and size-induced strain most strongly when added during synthesis but significantly reduced the particle strain when added to as-formed nano-ZnS. The same effects are useful to understand the properties and behavior of natural nano-ZnS formed as products of microbial activity, for example, in reducing environments, or of incidental nano-ZnS formed in organic wastes.

Copper (Cu) speciation in organic-waste (OW) amended soil: Instability of OW-borne Cu(I) sulfide and role of clay and iron oxide minerals.

The geochemistry of copper (Cu) is generally assumed to be controlled by organic matter in soils. However, the role of clay and iron oxide minerals may be understated. Soil density fractionation, X-ray diffraction (XRD), and X-ray absorption spectroscopy (XAS) were combined to assess the long-term behavior of Cu in an agricultural soil subject to organic waste application. Two unprecedented molecular environments of natural Cu (i.e. Cu inherited from the parent rock) in soils are reported: Cu dimer in the interlayer of vermiculite and Cu structurally incorporated within hematite. Moreover, the soil naturally containing Cu-vermiculite, Cu-hematite, but also Cu-kaolinite (Cutotal = 122 mg·kg-1) was amended over 11 years with Cu-rich pig slurry in which Cu was 100 % Cu(I) sulfide. Natural Cu associated with clay and iron oxide minerals persisted in the amended soil, but the exogenous Cu(I) sulfide was unstable. The increase in Cu concentration in the amended soil to 174 mg·kg-1 was accounted for the increase of Cu sorbed to kaolinite and Cu bound to organic matter. These results are important for better understanding the natural occurrence of Cu in soils and for assessing the environmental impacts of organic waste recycling in agricultural fields.

Recipes of Ancient Egyptian kohls more diverse than previously thought.

Kohl, a dark eye cosmetic, is a well-known part of Ancient Egyptian culture. Modern chemical analyses of kohls have largely found lead-based inorganic constituents, whereas earlier studies argued for a much broader range of constituents. Furthermore, organic materials in kohls remain severely understudied. This raises questions regarding the true diversity of materials and recipes used to produce kohls. We analysed the contents of 11 kohl containers from the Petrie Museum collection in London. The objects selected cover a broad range of times and locations in Egypt. Our multi-analytical approach allowed us to characterise both inorganic and organic components. Our data show that inorganic ingredients in kohl recipes are not only lead-based but also manganese- and silicon-based. Our analyses also revealed that organic ingredients derived from both plant and animal sources were commonly used in kohl recipes and sometimes even represent the main constituent. All these findings point towards more varied recipes than initially thought and significantly shift our understanding of Ancient Egyptian kohls.

Novel FGF9 variant contributes to multiple synostoses syndrome 3.

Multiple synostoses syndromes (SYNS) are autosomal dominant syndromes characterized by multiple joint fusions commonly involving the carpal-tarsal, interphalangeal, humeroradial, and cervical spine joints. They display genetic heterogeneity with pathogenic variants reported in four separate genes (NOG, GDF5, FGF9, and GDF6) defining four different SYNS forms. FGF9 variants have been reported in SYNS3, a SYNS with multiple synostoses, normal cognition, normal hearing, and craniosynostosis. Here, we report a novel FGF9 c.569G > C p.(Arg190Thr) variant identified by whole-exome sequencing in a patient with multiple bony abnormalities. The patient initially presented with elbow instability and decreased range of motion. Imaging revealed bilateral radial head deformities, carpal-tarsal fusions, brachydactyly, and osteoarthritis of the sacroiliac joints. In silico protein modeling of the identified FGF9 variant predicts decreased stability of ligand-receptor binding supporting the pathogenicity of this finding. This finding expands the repertoire of FGF9 variants and phenotypic information reported for SYNS3 and suggest that genotype phenotype correlations due to localization seem less likely and more so due to the consequence of the pathogenic variant on the receptor. This is useful in the counseling in families as more de novo variants emerge.

Influence of Articular Geometry and Tibial Tubercle Location on Patellofemoral Kinematics and Contact Mechanics.

Trochlear groove geometry and the location of the tibial tubercle, where the patellar tendon inserts, have both been associated with patellofemoral instability and can be modified surgically. Although their effects on patellofemoral biomechanics have been investigated individually, the interaction between the two is unclear. The authors' aim was to use statistical shape modeling and musculoskeletal simulation to examine the effect of patellofemoral geometry on the relationship between tibial tubercle location and patellofemoral function. A statistical shape model was used to generate new knee geometries with trochlear grooves ranging from shallow to deep. A Monte Carlo approach was used to create 750 knee models by randomly selecting a geometry and randomly translating the tibial tubercle medially/laterally and anteriorly. Each knee model was incorporated into a musculoskeletal model, and an overground walking trial was simulated. Knees with shallow trochlear geometry were more sensitive to tubercle medialization with greater changes in lateral patella position (-3.0 mm/cm medialization shallow vs -0.6 mm/cm deep) and cartilage contact pressure (-0.51 MPa/cm medialization shallow vs 0.04 MPa/cm deep). However, knees with deep trochlear geometry experienced greater increases in medial cartilage contact pressure with medialization. This modeling framework has the potential to aid in surgical decision making.

Contrasted microbial community colonization of a bauxite residue deposit marked by a complex geochemical context.

Bauxite residue is the alkaline byproduct generated during alumina extraction and is commonly landfilled in open-air deposits. The growth in global alumina production have raised environmental concerns about these deposits since no large-scale reuses exist to date. Microbial-driven techniques including bioremediation and critical metal bio-recovery are now considered sustainable and cost-effective methods to revalorize bauxite residues. However, the establishment of microbial communities and their active role in these strategies are still poorly understood. We thus determined the geochemical composition of different bauxite residues produced in southern France and explored the development of bacterial and fungal communities using Illumina high-throughput sequencing. Physicochemical parameters were influenced differently by the deposit age and the bauxite origin. Taxonomical analysis revealed an early-stage microbial community dominated by haloalkaliphilic microorganisms and strongly influenced by chemical gradients. Microbial richness, diversity and network complexity increased significantly with the deposit age, reaching an equilibrium community composition similar to typical soils after decades of natural weathering. Our results suggested that salinity, pH, and toxic metals affected the bacterial community structure, while fungal community composition showed no clear correlations with chemical variations.

Contrasted fate of zinc sulfide nanoparticles in soil revealed by a combination of X-ray absorption spectroscopy, diffusive gradient in thin films and isotope tracing.

Incidental zinc sulfide nanoparticles (nano-ZnS) are spread on soils through organic waste (OW) recycling. Here we performed soil incubations with synthetic nano-ZnS (3 nm crystallite size), representative of the form found in OW. We used an original set of techniques to reveal the fate of nano-ZnS in two soils with different properties. 68Zn tracing and nano-DGT were combined during soil incubation to discriminate the available natural Zn from the soil, and the available Zn from the dissolved nano-68ZnS. This combination was crucial to highlight the dissolution of nano-68ZnS as of the third day of incubation. Based on the extended X-ray absorption fine structure, we revealed faster dissolution of nano-ZnS in clayey soil (82% within 1 month) than in sandy soil (2% within 1 month). However, the nano-DGT results showed limited availability of Zn released by nano-ZnS dissolution after 1 month in the clayey soil compared with the sandy soil. These results highlighted: (i) the key role of soil properties for nano-ZnS fate, and (ii) fast dissolution of nano-ZnS in clayey soil. Finally, the higher availability of Zn in the sandy soil despite the lower nano-ZnS dissolution rate is counterintuitive. This study demonstrated that, in addition to nanoparticle dissolution, it is also essential to take the availability of released ions into account when studying the fate of nanoparticles in soil.

Uptake patterns of critical metals in alpine plant species growing in an unimpaired natural site.

The range of metals used for industrial purposes - electrical engineering, solar panels, batteries - has increased substantially over the last twenty years. Some of these emerging metals are the subject of geopolitical conflict and are considered critical as their unique properties make them irreplaceable. Many of these elements are poorly studied and their biogeochemical cycles still raise many questions. Aim of this study is to analyse the soil-to-plant transfer of some of these chemical elements and to shed light on their uptake pathways. For this purpose, the geological site of Jas Roux (France) was chosen as this alpine site is naturally rich in critical and potentially toxic elements such as As, Sb, Ba and Tl, but nevertheless is host to a high diversity of plants. Elemental concentrations were analysed in the topsoil and in 12 selected alpine plant species sampled in situ. Statistical tools were used to detect species dependent characteristics in elemental uptake. Our analyses revealed accumulation of rare earth elements by Saxifraga paniculata, selective oxyanion absorption by Hippocrepis comosa, accumulation of Tl by Biscutella laevigata and Galium corrudifolium and an exclusion strategy in Juniperus communis. These findings advance our understanding of the environmental behaviour of critical metals and metalloids such as V, As, Y, Sb, Ce, Ba and Tl and might bare valuable information for phytoremediation applications.

Cross-Sectional Risk Factors of Anterior Knee Pain in Adolescents.

Background: Anterior knee pain is a common complaint amongst adolescents, which can both be persistent, and in some cases, disabling. This study investigated a series of potential risk factors potentially linked to the onset of anterior knee pain. Methods: Questionnaires were distributed amongst 367 10-15 years-olds enrolled in the local school board. These surveys included questions on sex, age, sport participation, and history of anterior knee pain verified by a physician. Bivariate correlations and a binomial logistic regression were conducted. Overall rate of AKP in the population studied was 7.4%. The results indicated that past history of knee pain, age, and increased sports participation significantly correlated with increased risk of AKP. AKP was significantly more common in females than males. While sex, height, age, overall sport participation, participation in specific sports, and history of knee injury all contributed to the binomial model.

Silica-clay nanocomposites for the removal of antibiotics in the water usage cycle.

The increasingly frequent detection of resistant organic micropollutants in waters calls for better treatment of these molecules that are recognized to be dangerous for human health and the environment. As an alternative to conventional adsorbent material such as activated carbon, silica-clay nanocomposites were synthesized for the removal of pharmaceuticals in contaminated water. Their efficiency with respect to carbamazepine, ciprofloxacin, danofloxacin, doxycycline, and sulfamethoxazole was assessed in model water and real groundwater spiked with the five contaminants. Results showed that the efficacy of contaminant removal depends on the chemical properties of the micropollutants. Among the adsorbents tested, the nanocomposite made of 95% clay and 5% SiO2 NPs was the most efficient and was easily recovered from solution after treatment compared with pure clay, for example. The composite is thus a good candidate in terms of operating costs and environmental sustainability for the removal of organic contaminants.

Relationship Between Lateral Patellar Stability and Tibial Tubercle Location for Varying Patellofemoral Geometries.

The geometry of the patellofemoral joint affects function and pathology. However, the impact of trochlear groove depth on treatments for patellar instability and pain is not clear. Tibial tubercle osteotomy is a common surgical intervention for patellar instability where the tibial insertion of the patellar tendon (PT) is translated to align the extensor mechanism and stabilize the joint. The aim of this work was to investigate the interaction between trochlear groove depth and PT insertion and their effect on patellar stability. Patellofemoral geometry was modified based on a statistical shape model to create knees with a range of trochlear groove depths. A Monte Carlo approach was used and 750 instances of a musculoskeletal model were generated with varying geometry and anterior and medial transfer of the PT. Stability was assessed by applying a lateral perturbation force to the patella during simulation of overground walking. In knees with deep trochlear grooves, a medialized PT increased stability. However, in knees with shallow trochlear grooves, stability was maximized for tendon insertion ∼1 mm medial to its neutral location. This PT insertion also corresponded to the best alignment of the patella in the trochlear groove in these knees, indicating that good alignment may be important to maximizing stability. Anterior PT transfer had minimal effect on stability for all geometries. A better understanding of the effects of articular geometry and tubercle location on stability may aid clinicians in patient-specific surgical planning.

Differences in bulk and microscale yttrium speciation in coal combustion fly ash.

Coal combustion ash is a promising alternative source of rare earth elements (REE; herein defined as the 14 stable lanthanides, yttrium, and scandium). Efforts to extract REE from coal ash will depend heavily on the location and speciation of these elements in the ash. This study sought to identify the major chemical forms of yttrium (Y), as a representative REE in coal fly ash samples selected from major coal sources in the United States. Y speciation was evaluated using both bulk scale analyses (sequential extractions, Y K-edge X-ray absorption near-edge spectroscopy - XANES) and complementary analyses at the micron scale (micro-focus X-ray fluorescence and micro-XANES). Sequential selective extractions revealed that the REE were primarily in the residual (unextracted fraction) of coal fly ash samples. Extraction patterns for yttrium resembled those of the lanthanides, indicating that these elements were collectively dispersed throughout the aluminosilicate glass in fly ash. Bulk XANES analysis indicated that Y coordination states resembled a combination of Y-oxides, Y-carbonate, and Y-doped glass, regardless of ash origin. However, in the microprobe analysis, we observed "hotspots" of Y (∼10-50 µm) in some samples that included different Y forms (e.g., Y-phosphate) not observed in bulk measurements. Overall, this study demonstrated that yttrium (and potentially other REEs) are entrained in the glass phase of fly ash and that microscale investigations of individual high-REE regions in fly ash samples do not necessarily capture the dominant speciation.

Multi-scale X-ray computed tomography to detect and localize metal-based nanomaterials in lung tissues of in vivo exposed mice.

In this methodological study, we demonstrated the relevance of 3D imaging performed at various scales for the ex vivo detection and location of cerium oxide nanomaterials (CeO2-NMs) in mouse lung. X-ray micro-computed tomography (micro-CT) with a voxel size from 14 µm to 1 µm (micro-CT) was combined with X-ray nano-computed tomography with a voxel size of 63 nm (nano-CT). An optimized protocol was proposed to facilitate the sample preparation, to minimize the experimental artifacts and to optimize the contrast of soft tissues exposed to metal-based nanomaterials (NMs). 3D imaging of the NMs biodistribution in lung tissues was consolidated by combining a vast variety of techniques in a correlative approach: histological observations, 2D chemical mapping and speciation analysis were performed for an unambiguous detection of NMs. This original methodological approach was developed following a worst-case scenario of exposure, i.e. high dose of exposure with administration via intra-tracheal instillation. Results highlighted both (i) the non-uniform distribution of CeO2-NMs within the entire lung lobe (using large field-of-view micro-CT) and (ii) the detection of CeO2-NMs down to the individual cell scale, e.g. macrophage scale (using nano-CT with a voxel size of 63 nm).

Effect of field site hydrogeochemical conditions on the corrosion of milled zerovalent iron particles and their dechlorination efficiency.

Milled zerovalent iron (milled ZVI) particles have been recognized as a promising agent for groundwater remediation because of (1) their high reactivity with chlorinated aliphatic hydrocarbons, organochlorine pesticides, organic dyes, and a number of inorganic contaminants, and (2) a possible greater persistance than the more extensively investigated nanoscale zerovalent iron. We have used laboratory-scale batch degradation experiments to investigate the effect that hydrogeochemical conditions have on the corrosion of milled ZVI and on its ability to degrade trichloroethene (TCE). The observed pseudo first-order degradation rate constants indicated that the degradation of TCE by milled ZVI is affected by groundwater chemistry. The apparent corrosion rates of milled ZVI particles were of the same order of magnitude for hydrogeochemical conditions representative for two contaminated field sites (133-140mmolkg-1day-1, indicating a milled ZVI life-time of 128-135days). Sulfate enhances milled ZVI reactivity by removing passivating iron oxides and hydroxides from the Fe0 surface, thus increasing the number of reactive sites available. The organic matter content of 1.69% in the aquifer material tends to suppress the formation of iron corrosion precipitates. Results from scanning electron microscopy, X-ray diffraction, and iron K-edge X-ray adsorption spectroscopy suggest that the corrosion mechanisms involve the partial dissolution of particles followed by the formation and surface precipitation of magnetite and/or maghemite. Numerical corrosion modeling revealed that fitting iron corrosion rates and hydrogen inhibitory terms to hydrogen and pH measurements in batch reactors can reduce the life-time of milled ZVI particles by a factor of 1.2 to 1.7.

Nanoscale Coloristic Pigments: Upper Limits on Releases from Pigmented Plastic during Environmental Aging, In Food Contact, and by Leaching.

The life cycle of nanoscale pigments in plastics may cause environmental or human exposure by various release scenarios. We investigated spontaneous and induced release with mechanical stress during/after simulated sunlight and rain degradation of polyethylene (PE) with organic and inorganic pigments. Additionally, primary leaching in food contact and secondary leaching from nanocomposite fragments with an increased surface into environmental media was examined. Standardized protocols/methods for release sampling, detection, and characterization of release rate and form were applied: Transformation of the bulk material was analyzed by Scanning Electron Microscopy (SEM), X-ray-tomography and Fourier-Transform Infrared spectroscopy (FTIR); releases were quantified by Inductively Coupled Plasma Mass Spectrometry (ICP-MS), single-particle-ICP-MS (sp-ICP-MS), Transmission Electron Microscopy (TEM), Analytical Ultracentrifugation (AUC), and UV/Vis spectroscopy. In all scenarios, the detectable particulate releases were attributed primarily to contaminations from handling and machining of the plastics, and were not identified with the pigments, although the contamination of 4 mg/kg (Fe) was dwarfed by the intentional content of 5800 mg/kg (Fe as Fe2O3 pigment). We observed modulations (which were at least partially preventable by UV stabilizers) when comparing as-produced and aged nanocomposites, but no significant increase of releases. Release of pigments was negligible within the experimental error for all investigated scenarios, with upper limits of 10 mg/m2 or 1600 particles/mL. This is the first holistic confirmation that pigment nanomaterials remain strongly contained in a plastic that has low diffusion and high persistence such as the polyolefin High Density Polyethylene (HDPE).

Nanoparticle Uptake in Plants: Gold Nanomaterial Localized in Roots of Arabidopsis thaliana by X-ray Computed Nanotomography and Hyperspectral Imaging.

Terrestrial plants can internalize and translocate nanoparticles (NPs). However, direct evidence for the processes driving the NP uptake and distribution in plants is scarce at the cellular level. Here, NP-root interactions were investigated after 10 days of exposure of Arabidopsis thaliana to 10 mg·L-1 of negatively or positively charged gold NPs (∼12 nm) in gels. Two complementary imaging tools were used: X-ray computed nanotomography (nano-CT) and enhanced dark-field microscopy combined with hyperspectral imaging (DF-HSI). The use of these emerging techniques improved our ability to detect and visualize NP in plant tissue: by spectral confirmation via DF-HSI, and in three dimensions via nano-CT. The resulting imaging provides direct evidence that detaching border-like cells (i.e., sheets of border cells detaching from the root) and associated mucilage can accumulate and trap NPs irrespective of particle charge. On the contrary, border cells on the root cap behaved in a charge-specific fashion: positively charged NPs induced a higher mucilage production and adsorbed to it, which prevented translocation into the root tissue. Negatively charged NPs did not adsorb to the mucilage and were able to translocate into the apoplast. These observations provide direct mechanistic insight into NP-plant interactions, and reveal the important function of border cells and mucilage in interactions of plants with charged NPs.

Virtual Reality Compared with Bench-Top Simulation in the Acquisition of Arthroscopic Skill: A Randomized Controlled Trial.

BACKGROUND: Work-hour restrictions as set forth by the Accreditation Council for Graduate Medical Education (ACGME) and other governing bodies have forced training programs to seek out new learning tools to accelerate acquisition of both medical skills and knowledge. As a result, competency-based training has become an important part of residency training. The purpose of this study was to directly compare arthroscopic skill acquisition in both high-fidelity and low-fidelity simulator models and to assess skill transfer from either modality to a cadaveric specimen, simulating intraoperative conditions. METHODS: Forty surgical novices (pre-clerkship-level medical students) voluntarily participated in this trial. Baseline demographic data, as well as data on arthroscopic knowledge and skill, were collected prior to training. Subjects were randomized to 5-week independent training sessions on a high-fidelity virtual reality arthroscopic simulator or on a bench-top arthroscopic setup, or to an untrained control group. Post-training, subjects were asked to perform a diagnostic arthroscopy on both simulators and in a simulated intraoperative environment on a cadaveric knee. A more difficult surprise task was also incorporated to evaluate skill transfer. Subjects were evaluated using the Global Rating Scale (GRS), the 14-point arthroscopic checklist, and a timer to determine procedural efficiency (time per task). Secondary outcomes focused on objective measures of virtual reality simulator motion analysis. RESULTS: Trainees on both simulators demonstrated a significant improvement (p < 0.05) in arthroscopic skills compared with baseline scores and untrained controls, both in and ex vivo. The virtual reality simulation group consistently outperformed the bench-top model group in the diagnostic arthroscopy crossover tests and in the simulated cadaveric setup. Furthermore, the virtual reality group demonstrated superior skill transfer in the surprise skill transfer task. CONCLUSIONS: Both high-fidelity and low-fidelity simulation trainings were effective in arthroscopic skill acquisition. High-fidelity virtual reality simulation was superior to bench-top simulation in the acquisition of arthroscopic skills, both in the laboratory and in vivo. Further clinical investigation is needed to interpret the importance of these results.

Environmental exposure to TiO2 nanomaterials incorporated in building material.

Nanomaterials are increasingly being used to improve the properties and functions of common building materials. A new type of self-cleaning cement incorporating TiO2 nanomaterials (TiO2-NMs) with photocatalytic properties is now marketed. This promising cement might provide air pollution-reducing properties but its environmental impact must be validated. During cement use and aging, an altered surface layer is formed that exhibits increased porosity. The surface layer thickness alteration and porosity increase with the cement degradation rate. The hardened cement paste leaching behavior has been fully documented, but the fate of incorporated TiO2-NMs and their state during/after potential release is currently unknown. In this study, photocatalytic cement pastes with increasing initial porosity were leached at a lab-scale to produce a range of degradation rates concerning the altered layer porosity and thickness. No dissolved Ti was released during leaching, only particulate TiO2-NM release was detected. The extent of release from this batch test simulating accelerated worst-case scenario was limited and ranged from 18.7 ± 2.1 to 33.5 ± 5.1 mg of Ti/m2 of cement after 168 h of leaching. TiO2-NMs released into neutral aquatic media (simulate pH of surface water) were not associated or coated by cement minerals. The TiO2-NM release mechanism is suspected to start from freeing of TiO2-NMs in the altered layer pore network due to partial cement paste dissolution followed by diffusion into the bulk pore solution to the surface. The extent of TiO2-NM release was not solely related to the cement degradation rate.

Surgeon-driven neurophysiologic monitoring in a spinal surgery population.

BACKGROUND: This is a prospective observational study examining the use of a surgeon-driven intraoperative neurophysiologic monitoring system. Intraoperative neurophysiologic monitoring is becoming the standard of care for spinal surgeries with potential post-operative neurologic deficits. This standard applies to both adult and pediatric spinal surgery, but a shortage of appropriately trained and certified technologists and physiologists can compromise monitoring capabilities in some centers. A surgeon-driven, intra-operative monitoring system in the absence of a technologist or physiologist was examined for safety and efficacy. METHODS: One hundred thirty-five patients undergoing a variety of spinal procedures were monitored intra-operatively using a surgeon-driven neuro-monitoring system over a period of 80 months. Intraoperative monitoring included serial motor evoked potentials via an automated system that provided visual and audible feedback directly to the operative surgeon. Changes in monitoring and any corresponding surgical responses were evaluated and compared with postoperative neurological status. RESULTS: Of the 135 patients studied, intraoperative adjustments based on neuro-monitoring took place in four patients (3.0%): following reduction in spondylolisthesis, during instrumentation and fusion for a large kyphoscoliosis deformity, due to low hemoglobin, and because of traction. In all cases, surgical and/or anaesthetic modification restored MEPs toward baseline values. The accuracy of the neuro-monitoring results was sensitive to narcotics, benzodiazepines and changes in haemoglobin concentrations. No new postoperative deficits were observed in any patients in the cohort. CONCLUSIONS: The authors concluded that surgeon-driven neuro-monitoring was a safe and effective means of intraoperative neuro-monitoring during spinal surgery. It reliably detected intraoperative insults, which could potentially have resulted in postoperative neurologic compromise, and was not associated with any false-negative results in this cohort. Utility of surgeon-driven monitoring, using validated algorithms, may provide an option for this added safety measure even in cases where monitoring personnel are unavailable.