Hostile Sites Research Articles

Experimental analysis for comparison of wireless transmission technologies: Wi-Fi, Bluetooth, ZigBee and LoRa for mobile multi-robot in hostile sites

This research paper conducts a thorough comparison of four prominent transmission technologies suitable for mobile robots operating in challenging environments. Emphasizing key factors such as signal strength, noise resistance, and data transfer efficiency, the study aims to identify the optimal communication solution in hostile conditions. The exploration delves into the intricacies of received signal strength indication (RSSI) and signal-to-noise ratio (SNR), revealing distinctive traits and trade-offs among the technologies. Navigating through the complexities of frequency bands, modulation types, and communication topologies, the paper examines the impact of obstacles, energy consumption dynamics, and potential real-world applications. Beyond contributing to the fields of robotics and communication, the study offers practical insights for stakeholders seeking resilient and efficient transmission methods for mobile robotic applications. Advocating for long range (LoRa) as the preferred transmission technology in hostile environments, the paper highlights its unmatched immunity to noise, stability, and minimal energy consumption. These findings provide valuable guidance for technology choices in collaborative mobile robot operations under challenging conditions. This research sets the stage for future developments in robotic communication, underscoring the crucial role of selecting the right transmission means for mission-critical applications in hostile environments.

Outcomes of Cranioplasty Strategies for High-Risk Complex Cranial Defects: A 10-Year Experience.

Although the literature contains reports of the risks and complications of calvarial vault reconstruction for acquired defects, there are few publications addressing the specific patient population who require such reconstructions in cases preceded by prior infection, radiation, massive associated soft tissue trauma, and so on. We define such clinical presentations as a hostile environment for large surface area reconstruction. Our objective is to compare the safety and efficacy of autologous bone and alloplastic reconstruction in hostile cranial defects. An institutional review board-approved retrospective review of patients who underwent cranioplasty of a hostile site at the University of Alabama at Birmingham between January 2008 and December 2018 was performed. The patients were stratified into 3 groups based on the type of implant used: autogenous (bone), alloplastic (polyetheretherketone [PEEK], titanium, polymethyl methacrylate), or mixed (combination of bone and prosthetic). The primary outcome metric was a complication in the year after cranioplasty, identified by implant failure, necrosis, or infection. Statistical analysis included t tests and χ2 tests where appropriate using SPSS. There were 55 total cases in this period: 27 autogenous, 23 alloplastic, and 5 mixed. The purely autogenous group had the highest complication rate (44%), and the alloplastic group had the lowest complication rate (38%), which was not statistically different between the 3 groups (P = 0.121). When stratified by specific material used for reconstruction (27 bone, 14 PEEK, 10 titanium, and 5 polymethyl methacrylate), overall complication rate was statistically significant (P = 0.009, χ2 test), with PEEK implants having the lowest complication rate (21%). This analysis interestingly found that in the setting of hostile cranial defects, cranioplasties would benefit from the use of prosthetic implants instead of autologous bone grafts, not only for avoidance of donor site morbidity but also for a decrease in overall complications.

Up-regulation of pro-angiogenic molecules and events does not relate with an angiogenic switch in metastatic osteosarcoma cells but to cell survival features.

Osteosarcoma (OS) is the most frequent malignant bone tumor, affecting predominantly children. Metastases represent a major clinical challenge and an estimated 80% would present undetectable micrometastases at diagnosis. The identification of metastatic traits and molecules would impact in micrometastasis management. We demonstrated that OS LM7 metastatic cells secretome was able to induce microvascular endothelium cell rearrangements, an angiogenic-related trait. A proteomic analysis indicated a gain in angiogenic-related pathways in these cells, as compared to their parental-non-metastatic OS SAOS2 cells counterpart. Further, factors with proangiogenic functions like VEGF and PDGF were upregulated in LM7 cells. However, no differential angiogenic response was induced by LM7 cells in vivo. Regulation of the Fas-FasL axis is key for OS cells to colonize the lungs in this model. Analysis of the proteomic data with emphasis in apoptosis pathways and related processes revealed that the percentage of genes associated with those, presented similar levels in SAOS2 and LM7 cells. Further, the balance of expression levels of proteins with pro- and antiapoptotic functions in both cell types was subtle. Interestingly and of relevance to the model, Fas associated Factor 1 (FAF1), which participates in Fas signaling, was present in LM7 cells and was not detected in SAOS2 cells. The subtle differences in apoptosis-related events and molecules, together with the reported cell-survival functions of the identified angiogenic factors and the increased survival features that we observed in LM7 cells, suggest that the gain in angiogenesis-related pathways in metastatic OS cells would relate to a prosurvival switch rather to an angiogenic switch as an advantage feature to colonize the lungs. OS metastatic cells also displayed higher adhesion towards microvascular endothelium cells suggesting an advantage for tissue colonization. A gain in angiogenesis pathways and molecules does not result in major angiogenic potential. Together, our results suggest that metastatic OS cells would elicit signaling associated to a prosurvival phenotype, allowing homing into the hostile site for metastasis. During the gain of metastatic traits process, cell populations displaying higher adhesive ability to microvascular endothelium, negative regulation of the Fas-FasL axis in the lung parenchyma and a prosurvival switch, would be selected. This opens a new scenario where antiangiogenic treatments would affect cell survival rather than angiogenesis, and provides a molecular panel of expression that may help in distinguishing OS cells with different metastatic potential.

72957 Rethinking reconstructive strategies for complex cranial defects: A 10 year review of cranioplasty outcomes

ABSTRACT IMPACT: Up to 33% of patients of patients who undergo reconstruction have hostile defects with coexisting soft tissue and osseous defects due to prior radiation, prior failed cranioplasty or concurrent infections we seek to identify optimal strategies for these patients based on the experience of a southeastern tertiary referral center. OBJECTIVES/GOALS: Scalp and calvarial defects in patients may result from a number of etiologies including trauma, burns, tumor resections, infections, osteoradionecrosis, or congenital lesions. Our objective was to retrospectively evaluate the use of alloplastic reconstruction alongside autologous reconstruction for high risk cranial defects. METHODS/STUDY POPULATION: An IRB approved retrospective review of patients who underwent cranioplasty of a hostile site at a Southeastern tertiary referal center between January 2008 and December 2018 was performed. The patients were stratified into three groups based on the type of implant used: autogenous (bone), alloplastic (PEEK, Titanium, PMMA), or mixed (combination of both types of graft). The primary outcome metric was a complication in the year following cranioplasty, identified by flap or bone graft failure, necrosis, or infection. Statistical analysis included t-tests and chi-square tests where appropriate using SPSS. RESULTS/ANTICIPATED RESULTS: There were 43 total cases in this time period; 15 autogenous, 23 alloplastic, and 5 mixed. The purely autogenous group had the highest complication rate (85%) and the alloplastic group had the lowest complication rate (38%). When stratified by specific material used for reconstruction (15 bone, 14 PEEK, 10 titanium, and 5 PMMA), overall complication rate was statistically significant (p=0.009; chi square test) with PEEK implants having the lowest complication rate (21%). The analysis documented an overall complication rate that was statistically different between the three groups (p=0.012). DISCUSSION/SIGNIFICANCE OF FINDINGS: This analysis interestingly found that in the setting of hostile cranial defects, cranioplasties would benefit from the use of prosthetic implants instead of autologous bone grafts, not only for avoidance of donor site morbidity but also for decrease in overall complications.

Design of the Padma road and rail bridge, Bangladesh

The 6⋅15-km-long Padma road and rail bridge will become a landmark structure in Bangladesh and one of the largest river crossings in the world. The design encountered significant engineering challenges, particularly from the hostile site conditions and the merciless forces of nature. During the monsoon season the Padma River becomes fast flowing, and is susceptible to deep scour, demanding deep, piled foundations. The bridge site is also in an area of considerable seismic activity, leading to significant seismic loads being exerted on the structure. In the design, extensive engineering studies were conducted, advanced computational analyses were employed and innovative engineering solutions were developed to ensure that the bridge will be able to survive the challenges of nature in its long design working life. The project has accumulated a significant body of knowledge in seismic-resilient and scour-tolerant design, and it has advanced understanding of bridge behaviour in conditions of severe earthquake and deep riverbed scour.

Reconstructive approach to hostile cranioplasty: A review of the University of Chicago experience

Hostile sites for cranioplasty occur in patients with a history of radiation, infection, failed cranioplasty, CSF leak or acute infection. We review our series of autologous cranioplasties and present an approach to decision-making for reconstructing these complex defects. Patients with cranioplasty of a hostile cranial site at the University of Chicago between 2003 and 2012 were identified. They were stratified into three groups: chimeric free flap with vascularized bone (the vascular group), non-vascularized bone with local coverage (the non-vascular group) and non-vascularized bone with free flap (the mixed group). The primary outcome measure was a major complication in the year following cranioplasty, identified by flap or bone graft failure. We reviewed 33 cases; 14 "vascular", 13 "non-vascular", and 8 "mixed". There was no difference in flap or bone graft failure rates, which were 7% (1/14) for the vascular group, 8% (1/13) for the non-vascular group, and 0% for the mixed group (p = NS). Overall complication rate was statistically different between the three groups (p = 0.01). The non-vascular group had the lowest complication rate (31%). Based on our data we developed an assessment score (The University of Chicago CRAnial Severity Score of Hostility, CRASSH) for patient and treatment stratification. Vascularized, non-vascularized and mixed reconstructive methods can be used successfully in these challenging situations. We offer the CRASSH to aid in aligning patients with the most appropriate autologous reconstruction method for their hostile cranial sites.

Anti-inflammatory BmAFI of Brugia malayi modulates IgE, histamine and histamine receptor responses in Mastomys coucha

We recently reported that BmAFI, an anti-inflammatory fraction of Brugia malayi adult worm supports parasite development in the hostile peritoneal cavity (p.c.) of Mastomys coucha through a modified Th2 type of response that includes IL-13 and IgE response and anti-inflammatory IL-10 cytokine milieu. In the present study we investigated IgE related responses such as histamine release and modulation of histamine receptors 1 and 2 (HR1 and HR2) by presensitization with BmAFI of M. coucha infected with B. malayi. Sensitization with BmAFI alone enhanced IgE, histamine and HR2, but decreased HR1. Exposure of these animals to infection produced an IgE response that was inversely related to the parasite burden, and decreased histamine conc., and HR1 and HR2 expression. However, there was an early small increase in HR1 expression for a short period after exposure to infection. As expected, BmAFI sensitization supported parasite survival and development in the hostile p.c. of the host. These findings further establish that BmAFI decreases inflammatory/Th1 response and modulates Th2 responses to favour survival and development of the parasite in the hostile p.c. of the host and that IgE and histamine play an important role in this.

Egg wax from the cattle tick Rhipicephalus (Boophilus) microplus inhibits Pseudomonas aeruginosa biofilm

Rhipicephalus (Boophilus) microplus is constantly challenged during its life cycle by microorganisms present in their hosts or in the environment. Tick eggs may be especially vulnerable to environmental conditions because they are exposed to a rich and diverse microflora in the soil. Despite being oviposited in such hostile sites, tick eggs remain viable, suggesting that the egg surface has defense mechanisms against opportunistic and/or pathogenic organisms. R. microplus engorged females deposit a superficial wax layer onto their eggs during oviposition. This egg wax is essential for preventing desiccation as well as acting as a barrier against attack by microorganisms. In this study, we report the detection of anti-biofilm activity of R. microplus egg wax against Pseudomonas aeruginosa PA14. Genes involved in the functions of production and maintenance of the biofilm extracellular matrix, pelA and cdrA, respectively, were markedly downregulated by a tick egg-wax extract. Moreover, this extract strongly inhibited fliC gene expression. Instead of a compact extracellular matrix, P. aeruginosa PA14 treated with egg-wax extract produces a fragile one. Also, the colony morphology of cells treated with egg-wax extract appears much paler and brownish, instead of the bright purple characteristic of normal colonies. Swarming motility was also inhibited by treatment with the egg-wax extract. The inhibition of P. aeruginosa biofilm does not seem to depend on inhibition of the quorum sensing system since mRNA levels of the 3 regulators of this system were not inhibited by egg-wax extract.

Biological Invasions in Heterogeneous Environments: The Coupled Map Lattice Framework

Spatial heterogeneity greatly affects the population spread. Although the theory for biological invasion in heterogeneous spatially continuous habitats have received considerable attention, spatially discrete models have remained outside of the mainstream. In this study, we formulate and analyze a Coupled Map Lattice model for a single species population invading a two dimensional heterogeneous environment. The population growth rate and dispersal coefficient depend on the site quality. We first find an analytical criterium for the spread success in terms of the population growth rate and the dispersal coefficient in unfavorable regions. We then implemented our model for two distinct spatial configurations: periodical stripe-like and randomized environments. The spread rate is computed numerically and it shows a decrease with an increase of the fraction of the hostile sites. However, we observed that invasion success does not depend on the fraction of favorable sites but crucially depends on the connectivity of favorable regions.

Contrasting physiological responses of two co-occurring eucalypts to seasonal drought at restored bauxite mine sites

This study describes the physiological response of two co-occurring tree species (Eucalyptus marginata and Corymbia calophylla) to seasonal drought at low- and high-quality restored bauxite mine sites in south-western Australia. Seasonal changes in photosynthesis (A), stomatal conductance (g(s)), leaf water potential (ψ), leaf osmotic potential (ψ), leaf relative water content (RWC) and pressure-volume analysis were captured over an 18-month field study to (i) determine the nature and severity of physiological stress in relation to site quality and (ii) identify any physiological differences between the two species. Root system restriction at the low-quality site reduced maximum rates of gas exchange (g(s) and A) and increased water stress (midday ψ and daily RWC) in both species during drought. Both species showed high stomatal sensitivity during drought; however, E. marginata demonstrated a higher dehydration tolerance where ψ and RWC fell to -3.2 MPa and 73% compared with -2.4 MPa and 80% for C. calophylla. Corymbia calophylla showed lower g(s) and higher ψ and RWC during drought, indicating higher drought tolerance. Pressure-volume curves showed that cell-wall elasticity of E. marginata leaves increased in response to drought, while C. calophylla leaves showed lower osmotic potential at zero turgor in summer than in winter, indicating osmotic adjustment. Both species are clearly able to tolerate seasonal drought at hostile sites; however, by C. calophylla closing stomata earlier in the drought cycle, maintaining a higher water status during drought and having the additional mechanism of osmotic adjustment, it may have a greater capacity to survive extended periods of drought.

Control and Communications System for Remote Operation of an Infrared Radiometer

ABSTRACTAn infrared radiometer (the Infrared Radiometer for Millimetre Astronomy, IRMA) has been developed to measure the amount of water vapor in the atmosphere through its emission at 20 μm. Water vapor is the major contributor to signal phase error in submillimeter interferometric arrays and the principal source of opacity for telescopes operating at infrared wavelengths. While earlier versions of IRMA required hands‐on operation, the desire to operate at remote and often hostile sites necessitated the development of sophisticated and robust software. IRMA is a distributed, real‐time control and data acquisition system spread across three different computers, and can be controlled remotely over the network by command scripts or a graphical user interface client program.

Constructing identities in cyberspace: The case of eating disorders

This paper consists of a discourse analysis of data collected from websites that have been created by and for people who wish to share experiences of eating disorders in a positive and supportive environment. These sites have earned the broad description 'pro-ana' (where 'ana' is short for 'anorexia'). Site users have come to see themselves as a broad on-line community of like-minded individuals, but within this community there are many subgroups, and the boundaries between these subgroups are fiercely contested. In addition, frequent attacks on such websites in the media (charged with 'promoting eating disorders'), and by occasional hostile site visitors, have often forced the community into a defensive mode. The result is a rich tapestry of identity work. The analysis examines several 'pro-ana' sites and explores the way in which the identity is used to police the boundaries of the community, and ultimately, what it means 'to be ana' rather than 'mia' (bulimic), 'a normal', 'a faker', or even 'a hater'.

Complex Female Reproductive Tract Morphology: Its Possible Use in Postcopulatory Female Choice

Sperm competition has traditionally been modelled exclusively from the male perspective with females as passive participants. However females of many species have a physiologically and morphologically complex reproductive system (e.g. multiple sperm stores), which could enable them to control or influence offspring paternity by postcopulatory sperm selection. Previously the female reproductive tract has been modelled using a single sperm store. The model here describes the effects of a hostile site of insemination and two (or more) sperm stores in the outcome of sperm competition. If there was mortality of sperm directly after insemination, the main difference between having one or two stores was the number of possible choices. One-store females could choose the storage rates for different males and thereby influence paternity. Two-store females could choose the storage rates for different males differently in each store and later by choosing sperm from a particular store could favour a male at fertilisation. Without sperm mortality females with one store could hardly influence paternity. It was determined by female storage capacity relative to male ejaculate size. In contrast, females with two stores still achieved a clear separation of competing ejaculates, despite counteracting sperm displacement favouring last mates. This could give females the ultimate control over paternity through the selective use of sperm from each storage site, e.g. depending on environmental factors. As females of many animal groups may be able to spatially separate competing sperm in their multiple sperm stores (e.g. flies, spiders, birds) these results could have general significance for the evolution of female control of paternity.

Hostile base astronomy: Past, present and future

Automated observing at remote or hostile sites is briefly reviewed. Planning for a follow-up conference is announced.