Статті в журналах з теми "Multi-layered soft tissues"

Background and Objectives: Profound knowledge on the load-dependent behavior of human soft tissues is required for the development of suitable replacements as well as for realistic computer simulations. Regarding the former, e.g., the anisotropy of a particular biological tissue has to be represented with site- and direction-dependent particular mechanical values. Contrary to this concept of consistent mechanical properties of a defined soft tissue, mechanical parameters of soft tissues scatter considerably when being determined in tensile tests. In spite of numerous measures taken to standardize the mechanical testing of soft tissues, several setup- and tissue-related factors remain to influence the mechanical parameters of human soft tissues to a yet unknown extent. It is to date unclear if measurement extremes should be considered a variation or whether these data have to be deemed incorrect measurement outliers. This given study aimed to determine mechanical parameters of the human cranial dura mater as a model for human soft tissues using a highly standardized protocol and based on this, critically evaluate the definition for the term mechanical “variation” of human soft tissue. Materials and Methods: A total of 124 human dura mater samples with an age range of 3 weeks to 94 years were uniformly retrieved, osmotically adapted and mechanically tested using customized 3D-printed equipment in a quasi-static tensile testing setup. Scanning electron microscopy of 14 samples was conducted to relate the mechanical parameters to morphological features of the dura mater. Results: The here obtained mechanical parameters were scattered (elastic modulus = 46.06 MPa, interquartile range = 33.78 MPa; ultimate tensile strength = 5.56 MPa, interquartile range = 4.09 MPa; strain at maximum force = 16.58%, interquartile range = 4.81%). Scanning electron microscopy revealed a multi-layered nature of the dura mater with varying fiber directions between its outer and inner surface. Conclusions: It is concluded that mechanical parameters of soft tissues such as human dura mater are highly variable even if a highly standardized testing setup is involved. The tissue structure and composition appeared to be the main contributor to the scatter of the mechanical parameters. In consequence, mechanical variation of soft tissues can be defined as the extremes of a biomechanical parameter due to an uncontrollable change in tissue structure and/or the respective testing setup.

Medication-related osteonecrosis of the jaw (MRONJ) is a side effect of bisphosphonate therapy, characterised by exposed necrotic bone. The soft tissues of the oral mucosa no longer provide a protective barrier and MRONJ patients experience pain, infections and difficulties eating. We hypothesised that hydroxyapatite (Ca5(PO4)3(OH)) could reduce bisphosphonate concentrations and protect the oral mucosa by exploiting bisphosphonate’s calcium binding affinity. The effect of zoledronic acid (ZA) and pamidronic acid (PA) on the metabolism of oral fibroblasts, oral keratinocytes and three-dimensional oral mucosa models was investigated and then repeated in the presence of hydroxyapatite granules. Without hydroxyapatite, ZA and PA significantly reduced the metabolic activity of oral cells in a dose-dependent manner. Both drugs reduced epithelial thickness and 30 µM ZA resulted in loss of the epithelium. Hydroxyapatite granules had a protective effect on oral cells, with metabolic activity retained. Oral mucosa models retained their multi-layered epithelium when treated with ZA in the presence of hydroxyapatite granules and metabolic activity was comparable to controls. These results demonstrate hydroxyapatite granules protected oral soft tissues from damage caused by bisphosphonate exposure. Porous hydroxyapatite granules are currently used for socket preservation and this data suggests their potential to prevent MRONJ in at-risk patients.

Prolonged exposure to mechanical vibration has been associated with many musculoskeletal, vascular and sensorineural disorders of the foot from simple Plantar fasciitis and Achilles Tendonitis to complex ones as Tarsal tunnel syndrome (TTS) and Vibration white feet/toes. Foot-transmitted vibrations (FTV) are exposed to the occupants using vibrating equipment’s or standing on vibrating platforms. Prolonged exposure to foot-transmitted vibrations (FTV) can lead to syndromes like vibration white feet/toes may result in tingling sensation, blanching of the toes and even numbness in the feet and toes. A multi-layered two dimensional, plane strain finite element model is developed from the actual cross-section of the human foot to study the stresses and strains developed in the skin and soft tissues. The foot is assumed to be in contact with a steel plate, mimicking the interaction between the foot and the work platform. The skin and the subcutaneous tissue are considered as hyperelastic and viscoelastic. The effects of loading in the form of displacements and the frequency of sinusoidal vibration on a time-dependent stress/strain distribution at various depths in the subcutaneous tissue of the foot are investigated. The simulations indicate that lower frequency vibrations penetrate deep into the subcutaneous tissue while higher frequencies are concentrated in the outer skin layer. The present biomechanical model may serve as a valuable tool to study the response of foot of those who work on a vibrating platform.

The human head is a complex multi-layered structure of hard and soft tissues, governed by complex materials laws and interactions. Computational models of the human head have been developed over the years, reaching high levels of detail, complexity, and precision. However, most of the attention has been devoted to the brain and other intracranial structures. The skull, despite playing a major role in direct head impacts, is often overlooked and simplified. In this work, a new skull model is developed for the authors’ head model, the YEAHM, based on the original outer geometry, but segmenting it with sutures, diploë, and cortical bone, having variable thickness across different head sections and based on medical craniometric data. These structures are modeled with constitutive models that consider the non-linear behavior of skull bones and also the nature of their failure. Several validations are performed, comparing the simulation results with experimental results available in the literature at several levels: (i) local material validation; (ii) blunt trauma from direct impact against stationary skull; (iii) three impacts at different velocities simulating falls; (iv) blunt ballistic temporoparietal head impacts. Accelerations, impact forces, and fracture patterns are used to validate the skull model.

Decellularized extracellular matrix (dECM)–based biomaterials are of great clinical utility in soft tissue repair applications due to their regenerative properties. Multi-layered dECM devices have been developed for clinical indications where additional thickness and biomechanical performance are required. However, traditional approaches to the fabrication of multi-layered dECM devices introduce additional laminating materials or chemical modifications of the dECM that may impair the biological functionality of the material. Using an established dECM biomaterial, ovine forestomach matrix, a novel method for the fabrication of multi-layered dECM constructs has been developed, where layers are bonded via a physical interlocking process without the need for additional bonding materials or detrimental chemical modification of the dECM. The versatility of the interlocking process has been demonstrated by incorporating a layer of hyaluronic acid to create a composite material with additional biological functionality. Interlocked composite devices including hyaluronic acid showed improved in vitro bioactivity and moisture retention properties.

The aim of this article is to provide some insights on the osmo-inelastic response under stretching of annulus fibrosus of the intervertebral disc. Circumferentially oriented specimens of square cross section, extracted from different regions of bovine cervical discs (ventral-lateral and dorsal-lateral), are tested under different strain-rates and saline concentrations within normal range of strains. An accurate optical strain measuring technique, based upon digital image correlation, is used in order to determine the full-field displacements in the lamellae and fibers planes of the layered soft tissue. Annulus stress–stretch relationships are measured along with full-field transversal strains in the two planes. The mechanical response is found hysteretic, rate-dependent and osmolarity-dependent with a Poisson’s ratio higher than 0.5 in the fibers plane and negative (auxeticity) in the lamellae plane. While the stiffness presents a regional-dependency due to variations in collagen fibers content/orientation, the strain-rate sensitivity of the response is found independent on the region. A significant osmotic effect is found on both the auxetic response in the lamellae plane and the stiffness rate-sensitivity. These local experimental observations will result in more accurate chemo-mechanical modeling of the disc annulus and a clearer multi-scale understanding of the disc intervertebral function.

Hydrogel-based bio-inks have recently attracted more attention for 3D printing applications in tissue engineering due to their remarkable intrinsic properties, such as a cell supporting environment. However, their usually weak mechanical properties lead to poor printability and low stability of the obtained structures. To obtain good shape fidelity, current approaches based on extrusion printing use high viscosity solutions, which can compromise cell viability. This paper presents a novel bio-printing methodology based on a dual-syringe system with a static mixing tool that allows in situ crosslinking of a two-component hydrogel-based ink in the presence of living cells. The reactive hydrogel system consists of carboxymethyl chitosan (CMCh) and partially oxidized hyaluronic acid (HAox) that undergo fast self-covalent crosslinking via Schiff base formation. This new approach allows us to use low viscosity solutions since in situ gelation provides the appropriate structural integrity to maintain the printed shape. The proposed bio-ink formulation was optimized to match crosslinking kinetics with the printing process and multi-layered 3D bio-printed scaffolds were successfully obtained. Printed scaffolds showed moderate swelling, good biocompatibility with embedded cells, and were mechanically stable after 14 days of the cell culture. We envision that this straightforward, powerful, and generalizable printing approach can be used for a wide range of materials, growth factors, or cell types, to be employed for soft tissue regeneration.

Category: Trauma Introduction/Purpose: Displaced intraarticular calcaneus fractures comprise the majority of all calcaneus fractures. Many are indicated for open reduction and internal fixation (ORIF) through an extensile lateral approach (ELA). Unfortunately, this approach has reported complication rates of up to 32%. Improved edema management may reduce the incidence of complications. While compression wrapping has been shown to reduce wound complications in ankle arthroplasty, it has not been well studied in lower extremity trauma. This study aimed to evaluate the benefit of compression wrapping in calcaneus fractures treated surgically with an ELA. Methods: This study included 19 patients from 2015-2018 who underwent ORIF of closed intra-articular calcaneal fractures via an ELA by two surgeons. Demographics, comorbidities, fracture characteristics, and time to surgery were recorded. Following surgery, the extremity was initially immobilized in a short leg splint with transition to serial compression wrappings on postoperative day two. Wrappings involved application of multi-layered cotton cast padding and short stretch elastic bandages to the extremity in a distal to proximal fashion. Wraps were replaced every three days by trained physiotherapists until the two- week postoperative visit. The primary outcome was development of a wound complication. A minor complication was defined as wound appearance prompting initiation of oral or IV antibiotics or local wound care. A major complication was defined as development of flap necrosis or return to the OR for debridement. Results: Mean age was 47.7 years. 3 patients (15.7%) were diabetic, and 7 patients (36.8%) were smokers. Mean BMI was 26.9 kg/m2 (SD 4.4). Mean time to surgery was 11.4 days from injury (SD 6.93). The rate of minor soft tissue complication was 4/19 (26.3%); 2 patients required oral antibiotics only, 1 local wound care only, and 1 both antibiotics and local wound care. The rate of major complication was 2/19 (10.5%), with 1 patient requiring a return to OR and another requiring both a return to the OR and IV antibiotics. Of those patients, 1 was noncompliant with the protocol. All patients progressed to eventual soft tissue healing. Statistical analysis identified diabetes as a risk factor for any complication (p=0.02, relative risk 5.3). Conclusion: Compression wrapping resulted in a low incidence of major soft tissue complications in calcaneus fractures treated with an extensile lateral approach. Compression wrapping is an effective method of post-operative soft tissue management for calcaneal fractures, and may have further applications for similar high energy foot and ankle fractures. Further studies are warranted to determine whether this novel wound care technique is superior to standard post-operative wound care.

Background Surgery in the lesser pelvis is associated with a high complication rate as surgeons are spatially limited by solid anatomic structures and soft tissue borders. So far, only two-dimensional (2D) parameters have been used for risk stratification. Purpose To precisely measure the inner pelvic volume a computed tomography (CT)-based three-dimensional (3D) approach was established and compared to approximations by 2D parameter combinations. Material and Methods Thin-layered multi-slice CT datasets were used retrospectively for slice by slice depiction of the inner pelvic surface. The inner pelvic volume was then automatically compounded. Combinations of two to four 2D dimensions determined in 3D volume rendered reconstructions were correlated with the inner pelvic volume. Pearson’s correlation coefficient and Chi square test were used for statistical calculations. Significance level was set at P < 0.05. Results In total 142 patients (91 men, 51 women) aged 64.8 ± 10.6 years at surgery were included in the study. Mean calculated pelvic volume was 1031.13 ± 180.06 cm3 (men, 996.57 ± 172.43 cm3; women, 1093.34 ± 178.39 cm3). Best approximations were obtained by combination of the 2D measurements transverse inlet and pelvic height for men (r = 0.799, P < 0.05) as well as transverse inlet, obstetric conjugate, interspinous distance and pelvic depth for women (r = 0.855, P < 0.05). Conclusion We describe a precise and reproducible CT-based method for pelvic volumetry. A less time consuming but still reliable approximation can be achieved by combination of two to four 2D dimensions.

This article provides the review of the medical use of pH- and temperature-sensitive polymer hydrogels. Such polymers are characterised by their thermal and pH sensitivity in aqueous solutions at the functioning temperature of living organisms and can react to the slightest changes in environmental conditions. Due to these properties, they are called stimuli-sensitive polymers. This response to an external stimulus occurs due to the amphiphilicity (diphilicity) of these (co)polymers. The term hydrogels includes several concepts of macrogels and microgels. Microgels, unlike macrogels, are polymer particles dispersed in a liquid and are nano- or micro-objects. The review presents studies reflecting the main methods of obtainingsuch polymeric materials, including precipitation polymerisation, as the main, simplest, and most accessible method for mini-emulsion polymerisation, microfluidics, and layer-by-layer adsorption of polyelectrolytes. 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AbstractTissue engineering scaffolds with precisely controlled geometries, particularly with surface features smaller than typical cell dimensions (1-10μm), can improve cellular adhesion and functionality. In this paper, soft lithography was used to fabricate polydimethylsiloxane (PDMS) stamps of arrays of parallel 5μm wide, 5μm deep grooves separated by 45 μm ridges, and an orthogonal grid of lines with the same geometry. Several methods were compared for the fabrication of 3-D multi-layer polycaprolactone (PCL) scaffolds with precise features. First, micromolding in capillaries (MIMIC) was used to deliver the polymer into the small grooves by capillarity; however the resultant lines were discontinuous and not able to form complete lines. Second, spin coating and oxygen plasma were combined to build 3-D scaffolds with the line pattern. The resultant scaffolds had good alignment and adhesion between layers; however, the upper layer collapsed due to the poor mechanical rigidity. Finally, a new multi-layer micromolding (MMM) method was developed and successfully applied with the grid pattern to fabricate 3-D scaffolds. Scanning electron microscopy (SEM) characterization showed that the multi-layered scaffolds had high porosity and precisely controlled 3-D structures.

AbstractTissue engineering scaffolds with precisely controlled geometries, particularly with surface features smaller than typical cell dimensions (1-10μm), can improve cellular adhesion and functionality. In this paper, soft lithography was used to fabricate polydimethylsiloxane (PDMS) stamps of arrays of parallel 5μm wide, 5μm deep grooves separated by 45 μm ridges, and an orthogonal grid of lines with the same geometry. Several methods were compared for the fabrication of 3-D multi-layer polycaprolactone (PCL) scaffolds with precise features. First, micromolding in capillaries (MIMIC) was used to deliver the polymer into the small grooves by capillarity; however the resultant lines were discontinuous and not able to form complete lines. Second, spin coating and oxygen plasma were combined to build 3-D scaffolds with the line pattern. The resultant scaffolds had good alignment and adhesion between layers; however, the upper layer collapsed due to the poor mechanical rigidity. Finally, a new multi-layer micromolding (MMM) method was developed and successfully applied with the grid pattern to fabricate 3-D scaffolds. Scanning electron microscopy (SEM) characterization showed that the multi-layered scaffolds had high porosity and precisely controlled 3-D structures.

0. IntroductionIf we follow the line of much literature surrounding airports and urban mobility, the emphasis often falls on the fact that these spaces are designed to handle the mega-scale and super-human pace of mass transit. Airports have rightly been associated with velocity, as zones of rapid movement managed by enormous processing systems that guide bodies and things in transit (Pascoe; Pearman; Koolhaas; Gordon; Fuller & Harley). Yet this emphasis tends to ignore the spectrum of tempos and flows that are at play in airport terminals — from stillness to the much exalted hyper-rapidity of mobilized publics in the go-go world of commercial aviation.In this photo essay I'd like to pull a different thread and ask whether it's possible to think of aeromobility in terms of “uneven, differential mobility” (Bissell 280). What would it mean to consider waiting and stillness as forms of bodily engagement operating over a number of different scales and temporalities of movement and anticipation, without privileging speed over stillness? Instead of thinking mobility and stillness as diametrically opposed, can we instead conceive of them as occupying a number of different spatio-temporal registers in a dynamic range of mobility? The following is a provisional "visual ethnography" constructed from photographs of air terminal light boxes I have taken over the last five years (in Amsterdam, London, Chicago, Frankfurt, and Miami). Arranged into a "taxonomy of differentiality", each of these images comes from a slightly different angle, mode or directionality. Each view of these still images displayed in billboard-scale light-emitting devices suggests that there are multiple dimensions of visuality and bodily experience at play in these image-objects. The airport is characterized by an abundance of what appears to be empty space. This may be due to the sheer scale of mass transport, but it also arises from a system of active and non-active zones located throughout contemporary terminals. This photo series emphasises the "emptiness" of these overlooked left-over spaces that result from demands of circulation and construction.1. We Move the WorldTo many travellers, airport gate lounges and their surrounding facilities are loaded with a variety of contradictory associations and affects. Their open warehouse banality and hard industrial sterility tune our bodies to the vast technical and commercial systems that are imbricated through almost every aspect of contemporary everyday life.Here at the departure gate the traveller's body comes to a moment's rest. They are granted a short respite from the anxious routines of check in, body scans, security, information processing, passport scanning, itineraries, boarding procedures and wayfaring the terminal. The landside processing system deposits them at this penultimate point before final propulsion into the invisible airways that pipe them into their destination. We hear the broadcasting of boarding times, check-in times, name's of people that break them away from stillness, forcing people to move, to re-arrange themselves, or to hurry up. Along the way the passenger encounters a variety of techno-spatial experiences that sit at odds with the overriding discourse of velocity, speed and efficiency that lie at the centre of our social understanding of air travel. The airline's phantasmagorical projections of itself as guarantor and enabler of mass mobilities coincides uncomfortably with the passenger's own wish-fulfilment of escape and freedom.In this we can agree with the designer Bruce Mau when he suggests that these projection systems, comprised of "openings of every sort — in schedules, in urban space, on clothes, in events, on objects, in sightlines — are all inscribed with the logic of the market” (Mau 7). The advertising slogans and images everywhere communicate the dual concept that the aviation industry can deliver the world to us on time while simultaneously porting us to any part of the world still willing to accept Diners, VISA or American Express. At each point along the way these openings exhort us to stop, to wait in line, to sit still or to be patient. The weird geographies depicted by the light boxes appear like interpenetrating holes in space and time. These travel portals are strangely still, and only activated by the impending promise of movement.Be still and relax. Your destination is on its way. 2. Attentive AttentionAlongside the panoramic widescreen windows that frame the choreography of the tarmac and flight paths outside, appear luminous advertising light boxes. Snapped tightly to grid and locked into strategic sightlines and thoroughfares, these wall pieces are filled with a rotating menu of contemporary airport haiku and ersatz Swiss graphic design.Mechanically conditioned air pumped out of massive tubes creates the atmosphere for a very particular amalgam of daylight, tungsten, and fluorescent light waves. Low-oxygen-emitting indoor plants are no match for the diesel-powered plant rooms that maintain the constant flow of air to every nook and cranny of this massive processing machine. As Rem Koolhaas puts it, "air conditioning has launched the endless building. If architecture separates buildings, air conditioning unites them" (Koolhaas). In Koolhaas's lingo, these are complex "junkspaces" unifying, colliding and coalescing a number of different circulatory systems, temporalities and mobilities.Gillian Fuller reminds us there is a lot of stopping and going and stopping in the global circulatory system typified by air-terminal-space.From the packing of clothes in fixed containers to strapping your belt – tight and low – stillness and all its requisite activities, technologies and behaviours are fundamental to the ‘flow’ architectures that organize the motion of the globalizing multitudes of today (Fuller, "Store" 63). It is precisely this functional stillness organised around the protocols of store and forward that typifies digital systems, the packet switching of network cultures and the junkspace of airports alike.In these zones of transparency where everything is on view, the illuminated windows so proudly brought to us by J C Decaux flash forward to some idealized moment in the future. In this anticipatory moment, the passenger's every fantasy of in-flight service is attended to. The ultimate in attentiveness (think dimmed lights, soft pillows and comfy blankets), this still image is captured from an improbable future suspended behind the plywood and steel seating available in the moment —more reminiscent of park benches in public parks than the silver-service imagined for the discerning traveller.3. We Know ChicagoSelf-motion is itself a demonstration against the earth-binding weight of gravity. If we climb or fly, our defiance is greater (Appleyard 180).The commercial universe of phones, cameras, computer network software, financial instruments, and an array of fancy new gadgets floating in the middle of semi-forgotten transit spaces constitutes a singular interconnected commercial organism. The immense singularity of these claims to knowledge and power loom solemnly before us asserting their rights in the Esperanto of "exclusive rollover minutes", "nationwide long distance", "no roaming charges" and insider local knowledge. The connective tissue that joins one part of the terminal to a commercial centre in downtown Chicago is peeled away, revealing techno-veins and tendrils reaching to the sky. It's a graphic view that offers none of the spectacular openness and flights of fancy associated with the transit lounges located on the departure piers and satellites. Along these circulatory ribbons we experience the still photography and the designer's arrangement of type to attract the eye and lure the body. The blobby diagonals of the telco's logo blend seamlessly with the skyscraper's ribbons of steel, structural exoskeleton and wireless telecommunication cloud.In this plastinated anatomy, the various layers of commercially available techno-space stretch out before the traveller. Here we have no access to the two-way vistas made possible by the gigantic transparent tube structures of the contemporary air terminal. Waiting within the less travelled zones of the circulatory system we find ourselves suspended within the animating system itself. In these arteries and capillaries the flow is spread out and comes close to a halt in the figure of the graphic logo. We know Chicago is connected to us.In the digital logic of packet switching and network effects, there is no reason to privilege the go over the stop, the moving over the waiting. These light box portals do not mirror our bodies, almost at a complete standstill now. Instead they echo the commercial product world that they seek to transfuse us into. What emerges is a new kind of relational aesthetics that speaks to the complex corporeal, temporal, and architectural dimensions of stillness and movement in transit zones: like "a game, whose forms, patterns and functions develop and evolve according to periods and social contexts” (Bourriaud 11). 4. Machine in the CaféIs there a possible line of investigation suggested by the fact that sound waves become visible on the fuselage of jet planes just before they break the sound barrier? Does this suggest that the various human senses are translatable one into the other at various intensities (McLuhan 180)?Here, the technological imaginary contrasts itself with the techno alfresco dining area enclosed safely behind plate glass. Inside the cafes and bars, the best businesses in the world roll out their biggest guns to demonstrate the power, speed and scale of their network coverage (Remmele). The glass windows and light boxes "have the power to arrest a crowd around a commodity, corralling them in chic bars overlooking the runway as they wait for their call, but also guiding them where to go next" (Fuller, "Welcome" 164). The big bulbous plane sits plump in its hangar — no sound barriers broken here. It reassures us that our vehicle is somewhere there in the network, resting at its STOP before its GO. Peeking through the glass wall and sharing a meal with us, this interpenetrative transparency simultaneously joins and separates two planar dimensions — machinic perfection on one hand, organic growth and death on the other (Rowe and Slutsky; Fuller, "Welcome").Bruce Mau is typical in suggesting that the commanding problem of the twentieth century was speed, represented by the infamous image of a US Navy Hornet fighter breaking the sound barrier in a puff of smoke and cloud. It has worked its way into every aspect of the design experience, manufacturing, computation and transport.But speed masks more than it reveals. The most pressing problem facing designers and citizens alike is growth — from the unsustainable logic of infinite growth in GDP to the relentless application of Moore's Law to the digital networks and devices that define contemporary society in the first world. The shift of emphasis from speed to growth as a time-based event with breaking points and moments of rupture has generated new possibilities. "Growth is nonlinear and unpredictable ... Few of us are ready to admit that growth is constantly shadowed by its constitutive opposite, that is equal partners with death” (Mau 497).If speed in part represents a flight from death (Virilio), growth invokes its biological necessity. In his classic study of the persistence of the pastoral imagination in technological America, The Machine in the Garden, Leo Marx charted the urge to idealize rural environments at the advent of an urban industrialised America. The very idea of "the flight from the city" can be understood as a response to the onslaught of technological society and it's deathly shadow. Against the murderous capacity of technological society stood the pastoral ideal, "incorporated in a powerful metaphor of contradiction — a way of ordering meaning and value that clarifies our situation today" (Marx 4). 5. Windows at 35,000 FeetIf waiting and stillness are active forms of bodily engagement, we need to consider the different layers of motion and anticipation embedded in the apprehension of these luminous black-box windows. In The Virtual Window, Anne Friedberg notes that the Old Norse derivation of the word window “emphasizes the etymological root of the eye, open to the wind. The window aperture provides ventilation for the eye” (103).The virtual windows we are considering here evoke notions of view and shelter, open air and sealed protection, both separation from and connection to the outside. These windows to nowhere allow two distinct visual/spatial dimensions to interface, immediately making the visual field more complex and fragmented. Always simultaneously operating on at least two distinct fields, windows-within-windows provide a specialized mode of spatial and temporal navigation. As Gyorgy Kepes suggested in the 1940s, the transparency of windows "implies more than an optical characteristic; it implies a broader spatial order. Transparency means a simultaneous perception of different spatial locations" (Kepes 77).The first windows in the world were openings in walls, without glass and designed to allow air and light to fill the architectural structure. Shutters were fitted to control air flow, moderate light and to enclose the space completely. It was not until the emergence of glass technologies (especially in Holland, home of plate glass for the display of commercial products) that shielding and protection also allowed for unhindered views (by way of transparent glass). This gives rise to the thesis that windows are part of a longstanding architectural/technological system that moderates the dual functions of transparency and separation. With windows, multi-dimensional planes and temporalities can exist in the same time and space — hence a singular point of experience is layered with many other dimensions. Transparency and luminosity "ceases to be that which is perfectly clear and becomes instead that which is clearly ambiguous" (Rowe and Slutsky 45). The light box air-portals necessitate a constant fluctuation and remediation that is at once multi-planar, transparent and "hard to read". They are informatic.From holes in the wall to power lunch at 35,000 feet, windows shape the manner in which light, information, sights, smells, temperature and so on are modulated in society. "By allowing the outside in and the inside out, [they] enable cosmos and construction to innocently, transparently, converge" (Fuller, "Welcome" 163). Laptop, phone, PDA and light box point to the differential mobilities within a matrix that traverses multiple modes of transparency and separation, rest and flight, stillness and speed.6. Can You Feel It?Increasingly the whole world has come to smell alike: gasoline, detergents, plumbing, and junk foods coalesce into the catholic smog of our age (Illich 47).In these forlorn corners of mobile consumption, the dynamic of circulation simultaneously slows and opens out. The surfaces of inscription implore us to see them at precisely the moment we feel unseen, unguided and off-camera. Can you see it, can you feel it, can you imagine the unimaginable, all available to us on demand? Expectation and anticipation give us something to look forward to, but we're not sure we want what's on offer.Air travel radicalizes the separation of the air traveller from ground at one instance and from the atmosphere at another. Air, light, temperature and smell are all screened out or technologically created by the terminal plant and infrastructure. The closer the traveller moves towards stillness, the greater the engagement with senses that may have been ignored by the primacy of the visual in so much of this circulatory space. Smell, hunger, tiredness, cold and hardness cannot be screened out.In this sense, the airplanes we board are terminal extensions, flying air-conditioned towers or groundscrapers jet-propelled into highways of the air. Floating above the horizon, immersed in a set of logistically ordained trajectories and pressurized bubbles, we look out the window and don't see much at all. Whatever we do see, it's probably on the screen in front of us which disconnects us from one space-time-velocity at the same time that it plugs us into another set of relations. As Koolhaas says, junkspace is "held together not by structure, but by skin, like a bubble" (Koolhaas). In these distended bubbles, the traveler momentarily occupies an uncommon transit space where stillness is privileged and velocity is minimized. The traveler's body itself is "engaged in and enacting a whole kaleidoscope of different everyday practices and forms" during the course of this less-harried navigation (Bissell 282).7. Elevator MusicsThe imaginary wheel of the kaleidoscope spins to reveal a waiting body-double occupying the projected territory of what appears to be a fashionable Miami. She's just beyond our reach, but beside her lies a portal to another dimension of the terminal's vascular system.Elevators and the networks of shafts and vents that house them, are to our buildings like veins and arteries to the body — conduits that permeate and structure the spaces of our lives while still remaining separate from the fixity of the happenings around them (Garfinkel 175). The terminal space contains a number of apparent cul-de-sacs and escape routes. Though there's no background music piped in here, another soundtrack can be heard. The Muzak corporation may douse the interior of the elevator with its own proprietary aural cologne, but at this juncture the soundscape is more "open". This functional shifting of sound from figure to ground encourages peripheral hearing, providing "an illusion of distended time", sonically separated from the continuous hum of "generators, ventilation systems and low-frequency electrical lighting" (Lanza 43).There is another dimension to this acoustic realm: “The mobile ecouteur contracts the flows of information that are supposed to keep bodies usefully and efficiently moving around ... and that turn them into functions of information flows — the speedy courier, the networking executive on a mobile phone, the scanning eyes of the consumer” (Munster 18).An elevator is a grave says an old inspector's maxim, and according to others, a mechanism to cross from one world to another. Even the quintessential near death experience with its movement down a long illuminated tunnel, Garfinkel reminds us, “is not unlike the sensation of movement we experience, or imagine, in a long swift elevator ride” (Garfinkel 191).8. States of SuspensionThe suspended figure on the screen occupies an impossible pose in an impossible space: half falling, half resting, an anti-angel for today's weary air traveller. But it's the same impossible space revealed by the airport and bundled up in the experience of flight. After all, the dimension this figures exists in — witness the amount of activity in his suspension — is almost like a black hole with the surrounding universe collapsing into it. The figure is crammed into the light box uncomfortably like passengers in the plane, and yet occupies a position that does not exist in the Cartesian universe.We return to the glossy language of advertising, its promise of the external world of places and products delivered to us by the image and the network of travel. (Remmele) Here we can go beyond Virilio's vanishing point, that radical reversibility where inside and outside coincide. Since everybody has already reached their destination, for Virilio it has become completely pointless to leave: "the inertia that undermines your corporeity also undermines the GLOBAL and the LOCAL; but also, just as much, the MOBILE and the IMMOBILE” (Virilio 123; emphasis in original).In this clinical corner of stainless steel, glass bricks and exit signs hangs an animated suspension that articulates the convergence of a multitude of differentials in one image. Fallen into the weirdest geometry in the world, it's as if the passenger exists in a non-place free of all traces. Flows and conglomerates follow one another, accumulating in the edges, awaiting their moment to be sent off on another trajectory, occupying so many spatio-temporal registers in a dynamic range of mobility.ReferencesAppleyard, Donald. "Motion, Sequence and the City." The Nature and Art of Motion. Ed. Gyorgy Kepes. New York: George Braziller, 1965. Adey, Peter. "If Mobility Is Everything Then It Is Nothing: Towards a Relational Politics of (Im)mobilities." Mobilities 1.1 (2006): 75–95. Bissell, David. “Animating Suspension: Waiting for Mobilities.” Mobilities 2.2 (2007): 277-298.Bourriaud, Nicolas. Relational Aesthetics. Trans. Simon Pleasance and Fronza Woods. Paris: Les Presses du Reel, 2002. Classen, Constance. “The Deodorized City: Battling Urban Stench in the Nineteenth Century.” Sense of the City: An Alternate Approach to Urbanism. Ed. Mirko Zardini. 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