Investigating the research capacity and productivity of Canadian sports chiropractors.

Objectives: To investigate the research capacity and productivity of Canadian sports chiropractors. Methods: A cross-sectional survey (phase one) and scoping review (phase two) investigated the research capacity and productivity (from 2015-2020) of the Canadian sports chiropractic field. Results: Most respondents (72%) reported obtaining research training from fellowship and master's programs, with only 2 (1%) PhD qualifications identified. Approximately, 30% reported active involvement in research, with 28% being part-time clinician researchers. Access to human and technological research resources were limited. We identified 67 publications and 16 conference presentations within a five-year period, with clinical, population health, and basic science research as the areas most studied. Conclusion: The research effort of Canadian sports chiropractors is primarily conducted by clinicians involved in research on a part-time basis. Its research outputs predominantly reflect the research requirements of the RCCSS(C) Sports Sciences Residency Program, highlighting its contribution in developing capacity and producing research for the Canadian sports chiropractic field.

Objectifs: Étudier la capacité de recherche et la productivité des chiropraticiens du sport Canadiens. Méthodes: Une enquête transversale (première phase) et un examen de la portée (deuxième phase) ont permis d'étudier la capacité de recherche et la productivité (de 2015 à 2020) du domaine de la chiropratique sportive au Canada. Résultats: La plupart des répondants (72 %) ont déclaré avoir obtenu une formation en recherche dans le cadre de programmes de bourses et de maîtrises, et seulement 2 (1 %) ont indiqué avoir obtenu un doctorat. Environ 30 % des répondants ont déclaré participer activement à la recherche, 28 % d'entre eux étant des cliniciens-chercheurs à temps partiel. L'accès aux ressources humaines et technologiques de la recherche était limité. Nous avons recensé 67 publications et 16 présentations de conférences sur une période de cinq ans, les domaines les plus étudiés étant la recherche clinique, la recherche sur la santé des populations et la recherche en sciences fondamentales. Conclusion: L'effort de recherche des chiropraticiens du sport canadiens est principalement mené par des cliniciens impliqués dans la recherche à temps partiel. Leurs résultats de recherche reflètent surtout les exigences de recherche du programme de résidence en sciences du sport du Collège royal des sciences chiropratiques du sport du Canada (RCCSS(C)), soulignant leur contribution au développement des capacités et à la production de recherches pour le domaine de la chiropratique du sport au Canada.

Symptomatic tibial tunnel ganglion cyst presenting four years following an ACL hamstring autograft reconstruction: a case report of a rare complication of ACL surgery.

Objective: To highlight a case of an athlete with a symptomatic pretibial cyst 4-years post-ACL reconstruction surgery. Case presentation: A 23-year-old female soccer athlete presented with right-sided knee pain, locking and catching, and diminished sensation along the anteroinferior knee. She had a history of an ipsilateral ACL hamstring autograft four years prior. Physical evaluation revealed a visible and palpable swelling medial to the patellar tendon, limited and painful range, and hypoesthesia within the infrapatellar branch of the saphenous nerve. MRI revealed a tubular ganglion cyst along the anterior aspect of the tibial tunnel, medial to the patellar tendon, and anterior to the ACL graft. Summary: Post-surgical ganglion cyst formation in the reconstructed ACL is a rare complication that can present years following ACL surgery. This case aims to bring awareness to this condition as a potential long-term complication in the ACL-reconstructed athlete.

Objectif: Mettre en évidence le cas d'un athlète présentant un kyste ganglionnaire symptomatique du tunnel tibial quatre ans après une chirurgie de reconstruction du LCA. Exposé de cas: Une athlète de soccer âgée de 23 ans s'est présentée avec une douleur au genou droit, un blocage et un accrochage, et une diminution de la sensation le long du genou antéro-inférieur. Elle avait subi une autogreffe du ligament croisé antérieur ipsilatéral quatre ans auparavant. L'examen physique a révélé un gonflement visible et palpable en dedans du tendon rotulien, une amplitude limitée et douloureuse, et une hypoesthésie dans la branche sous-rotulienne du nerf saphène. L'IRM a révélé un kyste ganglionnaire tubulaire le long de la face antérieure du tunnel tibial, en dedans du tendon rotulien et en avant de la greffe du LCA. Résumé: La formation d'un kyste ganglionnaire post-chirurgical dans le LCA reconstruit est une complication rare qui peut se présenter des années après la chirurgie du LCA. Ce cas vise à attirer l'attention sur ce problème comme une complication potentielle à long terme chez l'athlète dont le LCA a été reconstruit.

Recognition and conservative management for a spectrum of sport-related scapholunate interosseous ligament injuries: a case series.

This case series presents four cases of scapholunate interosseous ligament (SLIL) injury. We discuss the process of early recognition and highlight difficulties encountered in current diagnostic and conservative management strategies. The cases profile interdisciplinary management of four scapholunate (SL) injuries that have different clinical presentations and injury mechanisms. Three sport-related SL injuries were managed conservatively by a sport specialist chiropractor and one sport-related case was self-managed. Management strategies included early wrist immobilization, soft tissue manual therapy, low-level laser therapy, proprioceptive and strengthening exercises, and early orthopedic referral. This case series highlights: (1) the spectrum of SL injuries (2) the importance of early specialty referral, (3) the paucity of literature with respect to conservative management of these injuries and (4) the role of manual therapy and rehabilitation professionals as part of the healthcare team in detecting and helping manage these wrist injuries.

Cette série de cas présente quatre cas de blessures du ligament interosseux scapho-lunaire (LISL). Nous discutons du processus de reconnaissance précoce et soulignons les difficultés rencontrées dans les stratégies actuelles de diagnostic et de gestion conservatrice. Ces cas illustrent la prise en charge interdisciplinaire de quatre lésions du ligament scapho-lunaire (SL) dont les tableaux cliniques et les mécanismes de blessure sont différents. Trois lésions scapho-lunaires liées au sport ont été prises en charge de manière conservatrice par un chiropraticien spécialiste du sport et un cas lié au sport a été auto-soigné. Les stratégies de prise en charge comprenaient une immobilisation précoce du poignet, une thérapie manuelle des tissus mous, une thérapie par laser à faible niveau, des exercices proprioceptifs et de renforcement, et une demande de consultation d'un orthopédiste le plus tôt possible. Cette série de cas met en évidence : (1) le spectre des lésions du ligament scapho-lunaire, (2) l'importance d'une orientation précoce vers un spécialiste, (3) la rareté des documents scientifiques concernant la gestion conservatrice de ces blessures et (4) le rôle des professionnels de la thérapie manuelle et de la réadaptation en tant que membres de l'équipe de soins de santé dans la détection et la gestion de ces blessures du poignet.

Identifying and prioritizing research to inform a research agenda for Canadian chiropractors working in sport - the Canadian sports chiropractic perspective.

Objectives: To identify and prioritize research to inform research agenda development for Canadian chiropractors working in sport. Methods: Clinicians, researchers and leaders from the Canadian sports chiropractic field were invited to participate in 1) a survey to refine a list of research priorities, 2) a Delphi procedure to determine consensus on these priorities, and 3) a prioritization survey. Results: The top three research priorities were 1) effects of interventions on athletic outcomes, 2) research about sports healthcare teams, and 3) clinical research related to spinal manipulative and mobilization therapy. The three highest ranked conditions to research were 1) low back pain, 2) neck pain, and 3) concussion. Collaborations with sports physicians and universities/ colleges were rated as important research collaborations to pursue. Conclusions: These results represent the Canadian sports chiropractic perspective to research priority setting and will be used alongside stakeholder input to set the first research agenda for the Canadian sports chiropractic field.

Objectifs: Définir et prioriser la recherche afin d'élaborer un programme de recherche pour les chiropraticiens canadiens travaillant dans le domaine du sport. Méthodologie: Des cliniciens, des chercheurs et des chefs de file du domaine de la chiropratique sportive canadienne ont été invités à participer à 1) un sondage pour préciser une liste de priorités de recherche, 2) une procédure Delphi pour déterminer le consensus sur ces priorités, et 3) un sondage d'établissement de priorités. Résultats: Les trois principales priorités de recherche sont 1) les effets des interventions sur les résultats sportifs, 2) la recherche sur les équipes de soins de santé dans le domaine du sport et 3) la recherche clinique liée à la thérapie de manipulation et de mobilisation de la colonne vertébrale. Les trois problèmes de santé les plus importants cités comme priorité de recherche sont 1) la lombalgie, 2) la cervicalgie et 3) les commotions cérébrales. Les collaborations avec les médecins du sport et les universités/collèges sont considérées comme des collaborations de recherche importantes à poursuivre. Conclusions: Ces résultats représentent le point de vue de la chiropratique sportive canadienne sur l'établissement des priorités en matière de recherche et seront utilisés avec les commentaires des intervenants pour établir le premier programme de recherche du domaine de la chiropratique sportive canadienne.

Multiple Wetting-Dewetting States of a Water Droplet on Dual-Scale Hierarchical Structured Surfaces.

Surfaces with microscale roughness can entail dual-scale hierarchical structures such as the recently reported nano/microstructured surfaces produced in the laboratory (Wang et al. Nature2020, 582, 55-57). However, how the dual-scale hierarchical structured surface affects the apparent wetting/dewetting states of a water droplet, and the transitions between the states are still largely unexplored. Here, we report a systematic large-scale molecular dynamics (MD) simulation study on the wetting/dewetting states of water droplets on various dual-scale nano/near-submicrometer structured surfaces. To this end, we devise slab-water/slab-substrate model systems with a variety of dual-scale surface structures and with different degrees of intrinsic wettability (as measured based on the counterpart smooth surface). The dual-scale hierarchical structure can be described as "nanotexture-on-near-submicrometer-hill". Depending on three prototypical nanotextures, our MD simulations reveal five possible wetting/dewetting states for a water droplet: (i) Cassie state; (ii) infiltrated upper-valley state; (iii) immersed nanotexture-on-hill state; (iv) infiltrated valley state; and (v) Wenzel state. The transitions between these wetting/dewetting states are strongly dependent on the intrinsic wettability (E in), the initial location of the water droplet, the height of the nanotextures (H 1), and the spacing between nanotextures (W 1). Notably, E in-H 1 and E in-W 1 diagrams show that regions of rich wetting/dewetting states can be identified, including regions where between one to five states can coexist.

A qualitative study investigating research priorities and investigative capacity in sports-focused chiropractic research, part 1 - identifying research priorities to inform a Delphi study.

OBJECTIVES: To identify sports-focused research priorities to inform the development of a research agenda for sports chiropractors. METHODS: A qualitative description study was conducted using semi-structured interviews with 20 sports chiropractic researchers from 8 different countries and focus group interviews with 12 sports chiropractic leaders from Canada. RESULTS: 150 research priorities were identified, and three main themes emerged: area of research, research actions, and research methodology. Six areas of research were identified: basic science and mechanism research, clinical research, health services research, population health, specific conditions and topics in sport, and chiropractic research in sport. Collaboration in research and contributing to the broader sports research effort were two subthemes identified as research actions, and the remaining codes were related to research methodology. CONCLUSIONS: The research priorities identified can be utilized to plan future research prioritization studies to inform a research agenda for the sports chiropractic field.

OBJECTIFS: Identifier les priorités de recherche axées sur le sport pour guider le développement d'un programme de recherche pour les chiropraticiens du sport. MÉTHODOLOGIE: Une étude de description qualitative a été menée à l'aide d'entretiens semi-structurés auprès de 20 chercheurs en chiropratique sportive de huit pays et d'entretiens en groupes de discussion avec 12 dirigeants de la chiropratique sportive du Canada. RÉSULTATS: 150 priorités de recherche ont été identifiées, et trois thèmes principaux sont ressortis : le domaine de recherche, les actions de recherche et la méthodologie de recherche. Six domaines de recherche ont été identifiés : la science fondamentale et la recherche sur les mécanismes, la recherche clinique, la recherche sur les services de santé, la santé de la population, des conditions et des sujets particuliers liés au sport et la recherche en chiropratique sportive. La collaboration dans la recherche et de façon plus générale, la contribution à l'effort de recherche sur le sport sont deux sous-thèmes identifiés comme des actions de recherche, et les autres codes sont liés à la méthodologie de recherche. CONCLUSIONS: Les priorités de recherche identifiées peuvent servir à préparer de futures études sur la priorisation de la recherche et à guider un programme de recherche dans le domaine de la chiropratique sportive.

Turning a Superhydrophilic Surface Weakly Hydrophilic: Topological Wetting States.

For water droplets placed on a rough or structured surface, two distinct wetting states commonly observed are either the Wenzel state (droplets wet the surface without showing air pockets beneath the droplets) or the Cassie state (droplets reside on top of the structure with air pockets trapped beneath the droplets). Herein, we show molecular dynamics (MD) simulation evidence of a previously unreported wetting behavior, i.e., the rise of multiple Wenzel states on the structured surfaces whose flat-surface counterparts are superhydrophilic (i.e., complete wetting surfaces with the hallmark of zero contact angle for water droplets). Specifically, our MD simulations show that on the structured surfaces with topology of closed-loop nanowalls/nanochannels, the water droplet can exhibit multiple Wenzel wetting states with the apparent contact angles >0°. We name these distinct multiple Wenzel states as "topological wetting states" because their existence can be attributed to the topology of the closed-loop nanowalls/nanochannels. Regardless of the shape of the closed loops, such topological wetting states can always arise due to the topological invariant (i.e., all closed loops entail the same topological genus value). This unusual wetting behavior is contrary to the conventional view (and to the prediction of the Wenzel equation), namely, a rough hydrophilic surface should have stronger hydrophilicity than its flat-surface counterpart.

Effects of Femtosecond Laser Surface Processed Nanoparticle Layers on Pool Boiling Heat Transfer Performance.

An experimental investigation of the effects of layers of nanoparticles formed during femtosecond laser surface processing (FLSP) on pool boiling heat transfer performance has been conducted. Five different stainless steel 304 samples with slightly different surface features were fabricated through FLSP, and pool boiling heat transfer experiments were carried out to study the heat transfer characteristics of each surface. The experiments showed that the layer(s) of nanoparticles developed during the FLSP processes, which overlay FLSP self-organized microstructures, can either improve or degrade boiling heat transfer coefficients (HTC) depending on the overall thickness of the layer(s). This nanoparticle layer thickness is an indirect result of the type of microstructure created. The HTCs were found to decrease with increasing nanoparticle layer thickness. This trend has been attributed to added thermal resistance. Using a focused ion beam milling process and transmission electron microscopy (TEM), the physical and chemical properties of the nanoparticle layers were characterized and used to explain the observed heat transfer results. Results suggest that there is an optimal nanoparticle layer thickness and material composition such that both the HTCs and critical heat flux (CHF) are enhanced.

Investigation of femtosecond laser induced ripple formation on copper for varying incident angle.

The hydrodynamic mechanisms associated with the formation of femtosecond laser induced ripples on copper for two angles of incidence are reported. Laser pulse length used for this work is 35 fs. A revised two-temperature model is presented that comprises transient changes of optical characteristics during the irradiation with femtosecond pulses to model relaxation processes and thermal response in bulk copper. The theoretical model takes into account the fluid flow dynamics that result in ripple periods shorter than the wavelength of the surface plasmon polaritons. Theoretical and experimental results are reported for incident angles of 0° and 45° relative to the surface normal. There is agreement between the experimentally measured and the theoretically predicted ripple periodicity for 50 pulses at 0° incidence. By contrast, for 100 pulses at 0° incidence, and 50 and 100 pulses at 45° incidence, the experimentally measured ripples have a larger period than the one predicted by the model while the trends in period with increased incident angle, and increased fluence are in agreement between the experimental and the theoretical results.

Epidemiological Risk Factors for Animal Influenza A Viruses Overcoming Species Barriers.

Drivers and risk factors for Influenza A virus transmission across species barriers are poorly understood, despite the ever present threat to human and animal health potentially on a pandemic scale. Here we review the published evidence for epidemiological risk factors associated with influenza viruses transmitting between animal species and from animals to humans. A total of 39 papers were found with evidence of epidemiological risk factors for influenza virus transmission from animals to humans; 18 of which had some statistical measure associated with the transmission of a virus. Circumstantial or observational evidence of risk factors for transmission between animal species was found in 21 papers, including proximity to infected animals, ingestion of infected material and potential association with a species known to carry influenza virus. Only three publications were found which presented a statistical measure of an epidemiological risk factor for the transmission of influenza between animal species. This review has identified a significant gap in knowledge regarding epidemiological risk factors for the transmission of influenza viruses between animal species.

Growth mechanisms of multiscale, mound-like surface structures on titanium by femtosecond laser processing.

Femtosecond laser surface processing (FLSP) can be used to functionalize many surfaces, imparting specialized properties such as increased broadband optical absorption or super-hydrophobicity/-hydrophilicity. In this study, the subsurface microstructure of a series of mound-like FLSP structures formed on commercially pure titanium using five combinations of laser fluence and cumulative pulse counts was studied. Using a dual beam Scanning Electron Microscope with a Focused Ion Beam, the subsurface microstructure for each FLSP structure type was revealed by cross-sectioning. The microstructure of the mounds formed using the lowest fluence value consists of the original Ti grains. This is evidence that preferential laser ablation is the primary formation mechanism. However, the underlying microstructure of mounds produced using higher fluence values was composed of a distinct smaller-grained α-Ti region adjacent to the original larger Ti grains remaining deeper beneath the surface. This layer was attributed to resolidification of molten Ti from the hydrodynamic Marangoni effect driven fluid flow of molten Ti, which is the result of the femtosecond pulse interaction with the material.

Micro/nanostructures formation by femtosecond laser surface processing on amorphous and polycrystalline Ni60Nb40.

Femtosecond laser surface processing is a technology that can be used to functionalize many surfaces, imparting specialized properties such as increased broadband optical absorption or superhydrophilicity/superhydrophobicity. In this study, two unique classes of surface structures, below surface growth (BSG) and above surface growth (ASG) mounds, were formed by femtosecond laser surface processing on amorphous and polycrystalline Ni60Nb40 with two different grain sizes. Cross sectional imaging of these mounds revealed thermal evidence of the unique formation processes for each class of surface structure. BSG mounds formed on all three substrates using the same laser parameters had similar surface morphology. The microstructures in the mounds were unaltered compared with the substrate before laser processing, suggesting their formation was dominated by preferential valley ablation. ASG mounds had similar morphology when formed on the polycrystalline Ni60Nb40 substrates with 100 nm and 2 [H9262]m grain size. However, the ASG mounds had significantly wider diameter and higher peak-to-valley heights when the substrate was amorphous Ni60Nb40. Hydrodynamic melting was primarily responsible for ASG mound formation. On amorphous Ni60Nb40 substrates, the ASG mounds are most likely larger due to lower thermal diffusivity. There was clear difference in growth mechanism of femtosecond laser processed BSG and ASG mounds, and grain size does not appear to be a factor.

Formation of aggregated nanoparticle spheres through femtosecond laser surface processing.

A detailed structural and chemical analysis of a class of self-organized surface structures, termed aggregated nanoparticle spheres (AN-spheres), created using femtosecond laser surface processing (FLSP) on silicon, silicon carbide, and aluminum is reported in this paper. AN-spheres are spherical microstructures that are 20-100 µm in diameter and are composed entirely of nanoparticles produced during femtosecond laser ablation of material. AN-spheres have an onion-like layered morphology resulting from the build-up of nanoparticle layers over multiple passes of the laser beam. The material properties and chemical composition of the AN-spheres are presented in this paper based on scanning electron microscopy (SEM), focused ion beam (FIB) milling, transmission electron microscopy (TEM), and energy dispersive x-ray spectroscopy (EDX) analysis. There is a distinct difference in the density of nanoparticles between concentric rings of the onion-like morphology of the AN-sphere. Layers of high-density form when the laser sinters nanoparticles together and low-density layers form when nanoparticles redeposit while the laser ablates areas surrounding the AN-sphere. The dynamic nature of femtosecond laser ablation creates a variety of nanoparticles that make-up the AN-spheres including Si/C core-shell, nanoparticles that directly fragmented from the base material, nanoparticles with carbon shells that retarded oxidation, and amorphous, fully oxidized nanoparticles.

Experimental explanation of the formation mechanism of surface mound-structures by femtosecond laser on polycrystalline Ni60Nb40.

Femtosecond laser surface processing (FLSP) is an emerging technique for creating functionalized surfaces with specialized properties, such as broadband optical absorption or superhydrophobicity/superhydrophilicity. It has been demonstrated in the past that FLSP can be used to form two distinct classes of mound-like, self-organized micro/nanostructures on the surfaces of various metals. Here, the formation mechanisms of below surface growth (BSG) and above surface growth (ASG) mounds on polycrystalline Ni60Nb40 are studied. Cross-sectional imaging of these mounds by focused ion beam milling and subsequent scanning electron microscopy revealed evidence of the unique formation processes for each class of microstructure. BSG-mound formation during FLSP did not alter the microstructure of the base material, indicating preferential valley ablation as the primary formation mechanism. For ASG-mounds, the microstructure at the peaks of the mounds was clearly different from the base material. Transmission electron microscopy revealed that hydrodynamic melting of the surface occurred during FLSP under ASG-mound forming conditions. Thus, there is a clear difference in the formation mechanisms of ASG- and BSG-mounds during FLSP.

Self­propelled droplets on heated surfaces with angled self­assembled micro/nanostructures.

Directional and ratchet-like functionalized surfaces can induce liquid transport without the use of an external force. In this paper, we investigate the motion of liquid droplets near the Leidenfrost temperature on functionalized self-assembled asymmetric microstructured surfaces. The surfaces, which have angled microstructures, display unidirectional properties. The surfaces are fabricated on stainless steel through the use of a femtosecond laser-assisted process. Through this process, mound-like microstructures are formed through a combination of material ablation, fluid flow, and material redeposition. In order to achieve the asymmetry of the microstructures, the femtosecond laser is directed at an angle with respect to the sample surface. Two surfaces with microstructures angled at 45° and 10° with respect to the surface normal were fabricated. Droplet experiments were carried out with deionized water and a leveled hot plate to characterize the directional and self-propelling properties of the surfaces. It was found that the droplet motion direction is opposite of that for a surface with conventional ratchet microstructures reported in the literature. The new finding could not be explained by the widely accepted mechanism of asymmetric vapor flow. A new mechanism for a self-propelled droplet on asymmetric three-dimensional self-assembled microstructured surfaces is proposed.

Enhanced pool-boiling heat transfer and critical heat flux on femtosecond laser processed stainless steel surfaces.

In this paper, we present an experimental investigation of pool boiling heat transfer on multiscale (micro/nano) functionalized metallic surfaces. Heat transfer enhancement in metallic surfaces is very important for large scale high heat flux applications like in the nuclear power industry. The multiscale structures were fabricated via a femtosecond laser surface process (FLSP) technique, which forms self-organized mound-like microstructures covered by layers of nanoparticles. Using a pool boiling experimental setup with deionized water as the working fluid, both the heat transfer coefficients and critical heat flux were investigated. A polished reference sample was found to have a critical heat flux of 91 W/cm2 at 40 °C of superheat and a maximum heat transfer coefficient of 23,000 W/m2 K. The processed samples were found to have a maximum critical heat flux of 142 W/cm2 at 29 °C and a maximum heat transfer coefficient of 67,400 W/m2 K. It was found that the enhancement of the critical heat flux was directly related to the wetting and wicking ability of the surface which acts to replenish the evaporating liquid and delay critical heat flux. The heat transfer coefficients were also found to increase when the surface area ratio was increased as well as the microstructure peak-to-valley height. Enhanced nucleate boiling is the main heat transfer mechanism, and is attributed to an increase in surface area and nucleation site density.

A fundamental understanding of the dependence of the laser-induced breakdown spectroscopy (LIBS) signal strength on the complex focusing dynamics of femtosecond laser pulses on either side of the focus.

We correlate the focusing dynamics of 50 femtosecond (fs) laser radiation as it interacts with a silicon sample to laser-induced breakdown spectroscopy (LIBS) signal strength. Presented are concentric ring-shaped variations in the electric field in the prefocus region due to lens aberrations and nonsymmetry between the prefocus and post-focus beam profile as a result of continuum generation, occurring around the focus. Experimental results show different signal trends for both atmospheric and vacuum conditions, attributed to the existence of a continuum for the former. Lens aberrations effects on the LIBS signal strength are investigated using a plano-convex spherical lens and an aspherized achromatic lens. High-resolution scanning electron micrographs of the silicon surface after ablation, along with theoretical simulations, reveal the electric field patterns near the focus. The research results contribute to fundamental understanding of the basic physics of ultrashort, femtosecond laser radiation interacting with materials.

Inactivation of the infectivity of two highly pathogenic avian influenza viruses and a virulent Newcastle disease virus by ultraviolet radiation.

Exposure of a virulent isolate of Newcastle disease virus (NDV) and two highly pathogenic avian influenza (HPAI) viruses, one of H7N1 subtype and the other H5N1 subtype, to a continuous ultraviolet B flux of approximately 90µW/cm(2), which models solar ultraviolet radiation, resulted in an exponential decline in infectivity with time. The time taken for a reduction in titre of 1 log10 median tissue culture infectious dose for each virus was: NDV, 69 min; H7N1 HPAI virus, 158 min; and H5N1 HPAI, virus 167 min.

Extraordinary shifts of the Leidenfrost temperature from multiscale micro/nanostructured surfaces.

In the present work, the effects of surface chemistry and micro/nanostructuring on the Leidenfrost temperature are experimentally investigated. The functional surfaces were fabricated on a 304 stainless steel surface via femtosecond laser surface processing (FLSP). The droplet lifetime experimental method was employed to determine the Leidenfrost temperature for both machine-polished and textured surfaces. A precision dropper was used to control the droplet size to 4.2 µL and surface temperatures were measured by means of an embedded thermocouple. Extraordinary shifts in the Leidenfrost temperatures, as high as 175 °C relative to the polished surface, were observed with the laser-processed surfaces. These extraordinary shifts were attributed to nanoporosity, reduction in contact angle, intermittent liquid/solid contacts, and capillary wicking actions resulting from the presence of self-assembled nanoparticles formed on the surfaces. In addition to the shift in the Leidenfrost temperature, significant enhancement of the heat transfer in the film boiling regime was also observed for the laser-processed surfaces; water droplet evaporation times were reduced by up to 33% for a surface temperature of 500 °C.

Formation of multiscale surface structures on nickel via above surface growth and below surface growth mechanisms using femtosecond laser pulses.

The formation of self-organized micro- and nano-structured surfaces on nickel via both above surface growth (ASG) and below surface growth (BSG) mechanisms using femtosecond laser pulse illumination is reported. Detailed stepped growth experiments demonstrate that conical mound-shaped surface structure development is characterized by a balance of growth mechanisms including scattering from surface structures and geometric effects causing preferential ablation of the valleys, flow of the surface melt, and redeposition of ablated material; all of which are influenced by the laser fluence and the number of laser shots on the sample. BSG-mound formation is dominated by scattering, while ASG-mound formation is dominated by material flow and redeposition. This is the first demonstration to our knowledge of the use of femtosecond laser pulses to fabricate metallic surface structures that rise above the original surface. These results are useful in understanding the details of multi-pulse femtosecond laser interaction with metals.