Tiny Space Research Articles

A novel chronic dural port platform for continuous collection of cerebrospinal fluid and intrathecal drug delivery in free-moving mice

BackgroundCerebrospinal fluid (CSF) provides a close representation of pathophysiological changes occurring in the central nervous system (CNS); therefore, it has been employed in pathogenesis research and biomarker development for CNS disorders. CSF obtained from valid mouse models relevant to CNS disorders can be an important resource for successful biomarker and drug development. However, the limited volume of CSF that can be collected from tiny intrathecal spaces and the technical difficulties involved in CSF sampling has been a bottleneck that has hindered the detailed analysis of CSF in mouse models.MethodsWe developed a novel chronic dural port (CDP) method without cannulation for CSF collection of mice. This method enables easy and repeated access to the intrathecal space in a free-moving, unanesthetized mouse, thereby enabling continuous long-term CSF collection with minimal tissue damage and providing a large volume of high-quality CSF from a single mouse. When combined with chemical biosensors, the CDP method allows for real-time monitoring of the dynamic changes in neurochemicals in the CSF at a one-second temporal resolution in free-moving mice. Moreover, the CDP can serve as a direct access point for the intrathecal injection of CSF tracers and drugs.ResultsWe established a CDP implantation and continuous CSF collection protocol. The CSF collected using CDP was not contaminated with blood and maintained physiological concentrations of basic electrolytes and proteins. The CDP method did not affect mouse’s physiological behavior or induce tissue damage, thereby enabling a stable CSF collection for up to four weeks. The spatio-temporal distribution of CSF tracers delivered using CDP revealed that CSF metabolism in different brain areas is dynamic. The direct intrathecal delivery of centrally acting drugs using CDP enabled real-time behavioral assessments in free-moving mice.ConclusionsThe CDP method enables the collection of a large volume of high-quality CSF and direct intrathecal drug administration with real-time behavioral assessment in free-moving mice. Combined with animal models relevant to CNS disorders, this method provides a unique and valuable platform for biomarker and therapeutic drug research.

The Housing Behavior of Malaysian Apartment Residents

The purpose of this study was to explore the housing behaviors of Malaysian apartment residents by investigating their space usage. During February 2019, 14 apartment units in Kuala Lumpur, Putra Jaya, Shah Alam, Petaling Jaya, and Klang were surveyed via interviews, observations, and measurement. Based on the author’s previous research, housing behavior was classified into personal activities, family activities, service activities, and social activities. The analysis yielded the following results. The bedroom, along with the living room and dining room, was the primary place for personal activities. The living room and dining room served as a major space for family and social activities. The dining room, in particular, served as a space for a variety of functions such as dining, studying, working, entertaining guests, and family gatherings. The yard is a unique space in Malaysian apartments for laundry as well as a second cooking space (wet kitchen). According to the findings of the study, families were satisfied with their apartment living environment; however, improvements to the comparatively tiny yard space and the security of the entrance were required.

On-orbit placement optimization of proximity defense shield for space station

Space station is under the increasing threaten caused by large amount of space debris on Earth orbit. Besides traditional active and passive defense measures, it is urgent to study active close-in defense strategy for protecting space station from space debris. In this paper, an active close-in defense mode is proposed for a space station based on a flexible and deployable proximity defense shield, while a hybrid procedure is formulated to optimize the on-orbit placement of the shield. First, an active close-in defense scheme for a space station is proposed. Second, the proximity defense process is modeled including orbit propagation and impact momentum transfer. Third, the orbital spatio-temporal evolution of the space debris and the proximity defense shield during the defense process are transformed into a multi-dimensional space probability distribution using the Poincaré section and the Gaussian mixture model. Then, based on probability optimization, the on-orbit placement of the proximity defense shield is optimized for protecting a space station from tiny space debris. Finally, comparison simulations demonstrate the effectiveness and feasibility of the proposed technique.

Practical reflection and benefits of making a food garden at home during Covid-19 pandemic

The partial lockdown during the Covid-19 pandemic in Indonesia pushed people to work from and spend more time at home. During this unprecedented time, many people pursued new hobbies in gardening, which proved to enhance physical and mental health. With anxieties regarding food insecurity, food gardens became a new urban trend. With a relatively tiny space available, it is possible to make an urban food garden in the front yard of a house using various cultivation techniques to maximize space. However, the implementation of food gardens in urban houses is quite challenging due to limited space. Then, we reflect on the practical process and personal benefits gained from developing a tiny food garden at home. The tiny food garden could produce a variety of vegetables and herbs, such as the spinach family, lettuce, Asian greens, the tomato family, eggplants, the basil family, mint, rosemary, moringas, and butterfly-pea flowers. It may support a household with few amounts of fresh emergency food in the worst scenario during the Covid-19 pandemic. Besides, developing a tiny food garden at home may also provide co-benefits such as enhanced subjective well-being, increased appreciation of food and the environment, motivating others to start gardening at home, and great personal satisfactions of consuming home-grown food. With all these socio-ecological co-benefits, home food garden must be integrated as a strategy to achieve urban sustainability and increase household food resilience.

Boosted self-interacting dark matter and XENON1T excess

We present a self-interacting boosted dark matter (DM) scenario as a possible explanation of the recently reported excess of electron recoil events by the XENON1T experiment. The Standard Model (SM) has been extended with two vector-like fermion singlets charged under a dark U(1)D gauge symmetry to describe the dark sector. While the presence of light vector boson mediator leads to sufficient DM self-interactions to address the small scale issues of cold dark matter, the model with sub-GeV scale DM can explain the XENON1T excess via elastic scattering of boosted DM component with electrons at the detector. Strong annihilation of DM into the light mediator leads to a suppressed thermal relic. A hybrid setup of dark freeze-out and non-thermal contribution from the late decay of a scalar can lead to correct relic abundance. We fit our model with XENON1T data and also find the final parameter space consistent with self-interaction of DM, DM-electron scattering rate, as well as astrophysical and cosmological observations. A tiny parameter space consistent with all these constraints and requirements can be further scrutinized in near-future experiments.

ON THE APPLICATION OF MATRIX SCALING AND POWERING METHODS OF SMALL STATE SPACES FOR SOLVING TRANSIENT DISTRIBUTION IN MARKOV CHAIN

The iterative solution methods for transient distribution in Markov chain is the computation of state probability distributions at an arbitrary point of time, which in the case of a discrete-time Markov chain means, finding the distribution at some arbitrary time step denoted , a row vector whose component is the probability that the Markov chain is in state at time step . In this study, the solutions of transient distribution in Markov chain using matrix scaling and powering methods for small state spaces which produce a significantly more accurate response in less time for some types of situations and also, tries to get to the end result as quickly as possible has been investigated, in order to provide some insight into the solutions of transient distribution of Markov chain. Our goal is to compute solutions and algorithms for tiny state spaces utilizing matrix scaling and powering approaches, which begin with an initial estimate of the solution vector and then comes closer and closer to the true solution with each step or iteration. With the help of several existing Markov chain laws, theorems, and formulas, matrices operations such as multiplication with one or more vectors, Padé variant of the matrix-powering and scaling technique are used. While the algorithms are explained, the transient distribution vector’s Padé approximants , and a backward error analysis of the Padé approximation are obtained for certain illustrative examples..

COPROLITES FROM CALVERT CLIFFS: MIOCENE FECAL PELLETS AND BURROWED CROCODILIAN DROPPINGS FROM THE CHESAPEAKE GROUP OF MARYLAND, U.S.A.

New finds of remarkable coprolites (fossilized feces) are here reported from the famous Miocene marine sediments of the Chesapeake Group exposed along Calvert Cliffs (Maryland, U.S.A.). Although vertebrate coprolites have been described from these deposits, here we provide the first description of tiny invertebrate fecal pellets. Thus far, these fecal pellets have only been found in the upper Miocene (Tortonian) St. Marys Formation. The micro-coprolites represent the coprulid ichnospecies Coprulus oblongus. The fecal pellets are found in small clusters or strings of dozens to masses of many hundreds. Pellets range in size from approximately 0.4 – 2.0 mm wide by 1.0 – 5.0 mm long, and range in color from gray to brownish black. Their length/diameter ratio is always very nearly 2. These coprulids have been found in a variety of Miocene fossils/concretions including a uranoscopid neurocranium, naticid gastropod, bivalve shells, barnacle tests, and in pellet-backfilled sinuous burrows through sediment. Because the fecal pellets are often found in tiny spaces or spaces thought to be inaccessible to shelled invertebrates, the coprulids are attributed to small and soft-bodied polychaetes or other annelids. Some coprolites attributed to crocodilians from the lower-middle Miocene Calvert Formation were tunneled into, presumably the result of coprophagy, by some unknown kind of organism(s). These compound trace fossils are in the form of burrows that excavate the coprolites, the sides of which are sculptured by scratch/gouge marks.

Airflow pattern and performance of attached ventilation for two types of tiny spaces

Airflow pattern and performance of attached ventilation for two types of tiny spaces

Editor's Note: Interdisciplinarity Reimagined

Editor's Note:Interdisciplinarity Reimagined1 Vilsoni Hereniko Once there was a tree called "niu."2 Every part of the tree was useful for sustaining physical and spiritual life: the Islanders used the leaves to weave beautiful baskets, fans, hats, floor coverings, and thatch, and they used the trunks for house posts, drums, and wooden vessels. The Islanders drank the sweet nectar of the tree's coconuts and snacked on the firm flesh all day long; they made cooking sauces from the fermented flesh, wove strong rope from the husks, and made coconut milk to cook all kinds of delicious food dishes, desserts, and more. This was a tree that gave in all kinds of ways; every single part of the tree had a use. It was the most generous of trees, so the people called it "the tree of life." And the people were happy. Many years later, strangers came to this island with their money and seduced them with what money could buy: good-paying jobs, better houses, more material or foreign things to own, fancy cars and clothes, and so on. Their lawmakers also told them that if they wanted the foreigners from outside to keep coming with their dollars, they had to remove all the coconuts from the trees in case they fell on the heads of strangers who did not know anything about the tree. And the people believed. Suddenly, an invisible virus attacked all the people on the island, including the foreigners. So the strangers fled back to where they came from. The people lost their jobs. Without money, they could not afford to buy food from the supermarkets. Instead, they had to stay at home, wear masks around their faces, and protect themselves from the virus or they would die. While everyone and everything was on lockdown, the coconut trees started to bear fruit again. There being no people available to abort the emerging coconuts, the fruit of the trees grew to full maturity. When the pandemic was over and the Islanders reappeared, they saw the coconuts on the trees again! It was then that they REMEMBERED what the tree had meant to them before the strangers appeared. They said to themselves, "Never again!" And they resumed planting groves of coconut trees to [End Page ix] prepare for a future that is not dependent on the money the strangers brought with them. And niu, the coconut tree, the tree of life, smiled upon the Islanders and became its generous and giving self once again. And the people not only survived, but thrived.3 ________ We are the sea, we are the ocean, we must wake up to this ancient truth and together use it to overturn all hegemonic views that aim ultimately to confine us again, physically and psychologically, in the tiny spaces that we have resisted accepting as our sole appointed places and from which we have recently liberated ourselves. We must not allow anyone to belittle us again, and take away our freedom.4 Written in 1993, these powerful words by the Tongan academic and sage Epeli Hau'ofa concluded his famous essay "Our Sea of Islands," which inspired and challenged a whole generation of scholars and students in Pacific studies to remain free—in their thinking and in their pursuit of knowledge and creativity. The ripple effect of those words can still be felt today in Oceania and beyond. Even though Hau'ofa has passed away, his words still remain the most inspirational lines ever written by a Pacific Islander about our beloved region we call Oceania. These words could help us navigate our way within the colonial institution of the university where publication is necessary for survival. What has happened to the coconut tree around Waikīkī and urban Honolulu especially, and increasingly so around hotels and urban spaces around Oceania, is a visual representation of Hau'ofa's concern: that we will be forced to remain "in tiny spaces," confined, controlled, coerced in invisible ways to conform to hegemonic views or ways of representing ourselves and ideas (in "academic" writing as well) that are not unique to us. To each of us. What happens then is that we...

Future of Online Signatures: The One-Sign Feature

Have you ever messed up trying to sign a document digitally? If you did, then you know how difficult it is to use your index finger as a god-given stylus; To draw between those tiny exact spaces and redo it, again and again, in case the screen does not capture your finger drawn signature properly. Shouldn’t there be a better convenient, hassle-free way to do this? Something that ensures authenticity, accountability, security, and at the same time doesn’t feel like ‘draw-wrestling’? Here we present our solution in the form of a software system as a hypothesis going by the name ‘the One sign feature’. The feature is a crossplatform, profile-based, Sign Insertion method, which works when a password is successfully accepted, thereby inserting the sign on the document where selected. It is proposed as a solution to the "Small Screen, Too Much Work, Less Authenticity and Less Accountability" problem statement, which are common limitations of all the current solution offerings. The paper does a brief comparative study of all the popular technologies available in the industry used to digitally sign a document; discussing their drawbacks and drastic impacts of their limitations in terms of loss of money, productivity, and time. All this with the motive to prove that the 'Smart era' of Online Signatures is yet to come to its breakthrough and that there is still a wide opportunity gap for a system that could increase Data Privacy, overcome the limitations of the current systems, and eliminate loopholes.

A Method for Completing Economic Load Dispatch Using the Technique of Narrowing Down Area

Economic load dispatch solutions based on published methods, both conventional and artificial, have been very well-formulated through point-to-point movement methodologies to reach a convergence point. Iteration always starts from the starting point to obtain the following solution point, leading to the convergence point. This paper presents a new method to solve economic load dispatch problems by narrowing the minimum and maximum power limits between generator units. This idea approximates the solution point with a tiny space formed by the very narrow power limits of each generator. The methodology used is the distance between the minimum and maximum power limits of each generator divided into several segments. Then, the best segment is determined by the minimum total cost calculated based on the center point of the segment. Continue to the following iteration process until the best segment is the smallest. This iteration process is another artificial method that works without calculus calculations, so it does not depend on the objective function. This method has been validated using two generator units with differentiable objective functions, with calculation accuracy less than 0.00001 MW of the power distance of the generator limit, and the iteration stops at the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$23^{\mathrm {rd}}$ </tex-math></inline-formula> step. Furthermore, this method has been successfully applied to the nondifferentiable objective function, piecewise and valve point effects.

Far Beyond the Moon: A History of Life Support Systems in the Space Age by David P. D. Munns and Kärin Nickelsen (review).

Reviewed by: Far Beyond the Moon: A History of Life Support Systems in the Space Age by David P. D. Munns and Kärin Nickelsen Jordan Bimm (bio) Far Beyond the Moon: A History of Life Support Systems in the Space Age By David P. D. Munns and Kärin Nickelsen. Pittsburgh: University of Pittsburgh Press, 2021. Pp. 206. Make no mistake, this is a book about shit in space. The sanitized title and cover design don't do justice to what's inside this important and far-ranging history of human waste's various roles in sealed artificial environments designed for space travel. The problem of what to do with astronaut poo has been there since the start of human spaceflight, and coauthors David Munns and Kärin Nickelsen note that sixty-plus years later, a long-term sustainable solution remains elusive. From stick-on poop collection bags to vacuum-assisted commodes to aquarium-like algae habitats converting solid waste into (theoretically) edible food, the array of [End Page 302] engineering and life sciences approaches examined ranges from simple and pragmatic to complex and far-future directed. The first book-length historical treatment of the topic, this frank, unflinching look at an unglamorous, sometimes embarrassing, yet absolutely essential aspect of space technology aims to remove what the authors convincingly argue has been a limiting stigma. We need to talk about shit in space, and Far Beyond the Moon is a thought-provoking conversation starter. The book moves mostly chronologically through a selection of little-known but fascinating American and Soviet projects from the 1960s to the 1990s, emblematic of the work trajectories on this issue, and evocative of themes the authors want to highlight. These include how waste is conceptualized; talked about (or not); incorporated into ecological and technological schemata; collected, stored, or processed; and finally centered in totalizing visions of environment and environmentalism extending far beyond tiny space cabins to experimental megastructures and the entire Earth. The result is an illuminating history of the space race and its aftermath from the new perspective of sanitary engineering. First, the authors dispel the notion that NASA only began work on the problems of long-term living in space in the 1970s, with Skylab extending post-Apollo missions from days to months (ch. 1). Munns and Nickelsen delve into the lesser-known history of NASA's life science research in the 1960s, and of work managing closed systems carried out between the Agency's Ames and Langley centers, as well as in the U.S. Air Force, and at private defense contractors Lockheed, Boeing, and General Electric. Next, the book focuses on fecal bags and the Algatron, two technologies developed in the 1960s representing vastly different approaches to dealing with astronaut poop (ch. 2). The stowable fecal bag used on NASA's famed Apollo missions was straightforward but also messy, smelly, and not reusable. In contrast, the Algatron—an experimental system developed at Berkeley with USAF funding but never flown in space—used algae cultures to endlessly recycle human waste into purified water and food. The book then pivots to the Soviet 1960s space program and ambitious human experiments at the Krasnoyarsk Institute, where scientists sealed test-subjects inside prototype closed ecological systems called "planet-ships" (ch. 3). Started in 1962, these culminated in a year-long experiment in 1967, when three subjects attempted to live and work in close quarters, growing hydroponic crops and recycling their waste with a system similar to the Algatron. Next, the authors take readers into the 1970s and waste-centric critiques of Gerard K. O'Neill's utopian plans for massive cylindrical space settlements, and then into the 1980s to real-life problems with space shuttle toilets and important links between astronaut psychology and hygiene in orbit (ch. 4). Their final chapter focuses on the best-known episode covered in the book, the infamous Biosphere 2 experiments in the early 1990s. Small groups attempted to live inside a giant sealed ecosystem [End Page 303] constructed in Arizona, with controversial results. Munns and Nickelsen place this project—often understood in terms of ecology—squarely within their history of spaceflight and sanitation. Historians of technology will find...

Simulation Research on Ventilation Control of Gaseous Pollutants in Urban Sentry Boxes

The tiny spaces of sentry boxes in cities, such as mobile security guards, highway toll booths, etc., are mostly located beside roads with harsh outdoor environments. Due to office demands, work windows often need to be kept or frequently opened. The intrusion of outdoor pollutants through the windows leads to the deterioration of the indoor air quality, and threatens the health of employees. This paper takes the gaseous pollutant NO2 as the representative and discusses the effective ventilation design scheme for improving the air quality in the sentry box with openings using two attached ventilation modes as the carrier. Taking the vertical wall-attached ventilation as an example, the formation of the air curtain at the window hole and its barrier performance to outdoor pollutants were studied. The conclusion is that when the air supply velocity is sufficient to form a complete air curtain at the window hole, it can effectively block the pollutants. The horizontal wall-attached ventilation shows that clean air is delivered to the space with openings, and the indoor air quality can also be well improved due to the dilution effect, but the effect of positive pressure control is not obvious due to the large opening. The conclusions can provide guidance for the ventilation design of sentry boxes with openings.

Scale of community centre: Clarification of the relation between scale and multifunctionality of community buildings

Abstract Community architecture is becoming a contributing tool for community development. In recent years it has gained popularity for its potential to encourage interaction and strengthen community ties. Community architecture represents not only the final product of architectural design but also the design process. It covers many kinds of community interventions and efforts of different extent; from tiny public space interventions to a complex design of community centres or comprehensive urbanistic structures focused on community well-being. Irrespective of the scale, their goal is the same; to provide space for leisure activities, networking, and reinforcing a sense of community. The most apparent design concept representing community architecture is the community centre, which provides space for meetings and interaction, and its program derives from the needs of a specific community. Furthermore, the design considers urbanistic relationships, architectural appearance, materials, spatial and functional requirements, interior design, equipment, and furniture solutions. The community architecture theory is an under-explored phenomenon in Slovakia. Thus, there is a lack of methodical design recommendations or guidelines for designing community centres as individual typological forms. The article focuses on the examination of 100 selected community facilities, identifying their prevalent features and their interrelationships. Presented research aims to examine fundamental characteristics of community centres, particularly their multifunctionality related to the character of the space, and the scale related to size in square meters. In conclusion, research suggests new size categories considering the relationship between the two factors.

Robust and Energy-Efficient Hardware: The Case for Asynchronous Design

The current technologies behind the design of semiconductor integrated circuits allow embedding billions of components in a singe silicon die, enabling the construction of very complex circuits in a tiny space, dissipating little energy and producing huge amounts of useful computational work. However, the current levels of integration for electronic components in silicon and similar materials are not easily managed, as parameter variations grow steadily, making the design tasks increasingly challenging. Synchronous techniques have dominated the digital system design landscape for many decades, but their costs are increasingly hard to cope with. Asynchronous design and particularly quasi-delay insensitive design promises to deal with the same challenges more gracefully in current advanced nodes, and possibly irrevocably in future technology nodes. This article proposes a review of the state of the art in using asynchronous circuit design techniques to achieve energy-efficient and robust digital circuit and system design. In particular, the definition of a robust digital circuit comprises addressing several aspects to which a digital system design is expected to be robust to, including: (1) voltage variations; (2) process variations; (3) temperature variations; (4) circuit aging. Besides addressing energy-efficiency and all the mentioned robustness aspects, this work also approaches some of the state-of-the-art tools available to deal with asynchronous design, and points to desirable research development to be conducted in these subjects in the future.

Nanoreactors: properties, applications and characterization

Abstract Nanoreactors are a type of chemical reactor that is used mostly in nanotechnology and nanobiotechnology. These unique reactors are critical to the operation of a nano foundry, which is essentially a foundry that produces goods on a nanoscale. Active sites, such as transitional metal species, can also be added to nanoreactors. In this situation, the NR’s limited area might impact reaction rate and mechanism by increasing the contacts between reactants and active sites and changing the concentration of the reactant at the active site. Immobilization of chiral active centers inside porous materials has received a lot of interest in this context, and there have been a lot of publications proving the benefits of nano space confinement in chemical processes. The specific mechanism in which enantioselectivities are strengthened has been clarified using molecular dynamics simulations. Nanoreactors are nanometer-sized chambers with the potential to improve chemical conversions by shielding catalysts from external effects and encapsulating reactors and catalysts in a tiny space for an extended period of time. Natural and synthetic nanoreactors are the two types of nanoreactors that can be found in general. The first group has a more selective function while also having a more complicated structure, whereas the second group has more variation and a simpler structure. Synthetic nanoreactors have so far been made with a variety of molecules and large types of molecules. The space inside the nanoreactors is a good environment for the production of various nanostructures, in addition to a wide range of chemical reactions. When chemical reactions are carried out in confined spaces with nanometer dimensions and micrometer volumes, the kinetics and the entire process path are altered. Nanoreactors are restricted areas used to execute specialized chemical processes. In the cells of living organisms, numerous simultaneous reactions are based on the same concept. As a result, various biological and chemical structures with nanoreactor characteristics are used in this strategy.

Self-interacting inelastic dark matter in the light of XENON1T excess

We propose a self-interacting inelastic dark matter (DM) scenario as a possible origin of the recently reported excess of electron recoil events by the XENON1T experiment. Two quasi-degenerate Majorana fermion DM interact within themselves via a light hidden sector massive gauge boson and with the standard model particles via gauge kinetic mixing. We also consider an additional long-lived singlet scalar which helps in realising correct dark matter relic abundance via a hybrid setup comprising of both freeze-in and freeze-out mechanisms. While being consistent with the required DM phenomenology along with sufficient self-interactions to address the small scale issues of cold dark matter, the model with GeV scale DM can explain the XENON1T excess via inelastic down scattering of heavier DM component into the lighter one. All these requirements leave a very tiny parameter space keeping the model very predictive for near future experiments.

Dynamic Nanoparticle Trapping By Cascaded Nanophotonic Traps in a Silicon Slot Waveguide

Nanophotonic traps integrated in a microfluidic channel are promising for next-generation multifunctional and flexible lab-on-chip systems, especially for researches in nanobiophotonics. Here we propose a slot waveguide with a nano-slit to produce a high gradient of optical field in a tiny space, which exhibits strong optical force to trap nanoparticles. Moreover, the slits can be cascaded along the direction of light propagation to form a large array of optical traps, with negligible reflection and loss, which is expected to be useful in study of biological nanoparticles. The trapping dynamics of nanoparticles to the proposed nanophotonic traps is analyzed, which reveals physically cascaded trapping processes enabled by the slot and the slit, respectively. The motion trajectories of the particles of 50 nm in diameter are obtained with the Brownian motion taken into account, which shows successful trapping of the nanoparticles.

Die prähospitale Therapie eines Spannungspneumothorax bei Kindern – welche Entscheidungen treffen wir?

The preclinical treatment of atraumatic or spontaneous tension pneumothorax remains aparticular challenge in pediatric patients. Currently recommended interventions for decompression are either finger thoracostomy or needle decompression. Due to the tiny intercostal spaces, finger thoracostomy may not be feasible in small children and surgical preparation may be necessary. In needle decompression, the risk of injuring underlying vital structures is increased because of the smaller anatomic structures. As most emergency physicians do not regularly work in pediatric trauma care, decompression of tension pneumothorax is associated with significant uncertainty; however, in this rare emergency situation, consistent and goal-oriented action is mandatory and lifesaving. An assessment of pre-existing experience and commonly used techniques therefore seems necessary to deduce the need for future education and training. In this study an online survey was created to evaluate the experience and the favored prehospital treatment of tension pneumothorax in children among German emergency physicians. An online survey was conducted with 43questions on previous experience with tension pneumothorax in children, favored decompression technique and anatomical structures in different age groups. Surveyed were the emergency physicians of the ground-based emergency medical service of the University Medical Center Mannheim, the German Air Rescue Service (DRF) and the pediatric emergency medical service of the City of Munich. More than half of all respondents stated that there was uncertainty about the procedure of choice. Needle decompression was favored in smaller children and mini-thoracostomy in older children. In comparison with the literature, the thickness of the chest wall was mostly estimated correctly by the emergency medical physicians. The depth of the vital structures was underestimated at most of the possible insertion sites in all age groups. At the lateral insertion sites on the left hemithorax, however, the distance to the left ventricle was overestimated. The caliber of the needle selected for decompression tended to be too large, especially in younger children. Even though having interviewed an experienced group of prehospital emergency physicians, the experience in decompression of tension pneumothorax in children is relatively scant. Knowledge of chest wall thickness and depth to vital structures is sufficient, the choice of needle calibers tends to be too large but still reasonable. For many providers alarge amount of uncertainty about the right choice of technique and equipment arises from the challenge of decompressing atension pneumothorax in children and therefore further theoretical education and regular training are required for safe performance of the procedure.

A capsule-based collision detection approach of irregular objects in virtual maintenance

PurposeVirtual maintenance simulation is of great importance to help designers find and avoid design problems. During its simulation phase, besides the high precision requirement, collision detection must be suitable for all irregular objects in a virtual maintenance environment. Therefore, in this paper, a collision detection approach is proposed based on encapsulation for irregular objects in the virtual maintenance environment.Design/methodology/approachFirst, virtual maintenance simulation characteristics and several commonly used bounding boxes methods are analyzed, which motivates the application of encapsulation theory. Based on these, three different encapsulation methods are oriented to the needs of simulation, including encapsulation of rigid maintenance objects, flexible maintenance objects and maintenance personnel. In addition, to detecting collisions accurately, this paper divides the detection process into two stages. That is, in the first stage, a rough detection is carried out and then a tiny slice space is constructed to generate corresponding capsule groups, which will be redetected in the secondary stage. At last, several case studies are applied to illustrate the performance of the methodology.FindingsThe automatic construction algorithm for bounding boxes can be adapted to all forms of objects. The number of detection primitives are greatly reduced. It introduces the reachable space of the human body in maintainability as the collision search area.Originality/valueThe advantages of virtual maintenance simulation could also be advantageous in the industry with further studies. The paper believes this study is of particular interest to the readers of your journal.