Complete Failure Research Articles

Designing for climate change: twenty-five design features to improve sanitation technology resilience in low- and middle- income countries

AbstractClimate change is exacerbating events such as floods and droughts, and trends including sea-level rise, leading to failures in sanitation technologies, increased public health risks and environmental pollution. To reduce these risks, it is crucial to incorporate climate resilience into sanitation technology designs. In this study, we reviewed academic and selected grey literature and identified 25 design features that can contribute to the technology’s resilience to an increasingly volatile and extreme climate. Design features that were conceptually similar were collated into seven categories. These categories included: (i) avoid exposure to hazards, (ii) withstand exposure to hazards, (iii) enable flexibility, (iv) contain failures, (v) limit consequences of complete failure, (vi) facilitate fast recovery and (vii) features that provide resilience benefits beyond technological resilience. In this paper we define the categories and design features, and provide examples of each feature in practice. We also outline how the resilience design features can support sanitation designers and implementers to critique the climate resilience of sanitation technology, and prompt more resilient designs of sanitation technology.

Rising orthotospovirus incidence in India: Challenges and advances in management

Orthotospoviruses (OV) have emerged as a significant agricultural threat in India, posing a severe risk to critical crops, including tomato, chilli, watermelon and groundnut. This review explores the rising incidence of OV, including Groundnut Bud Necrosis Orthotospovirus (GBNV), Watermelon Bud Necrosis Orthotospovirus (WBNV), Capsicum Chlorosis Orthotospovirus (CaCV), Peanut Yellow Spot Orthotospovirus (PYSV), Iris yellow spot Orthotospovirus (IYSV) and Tomato Spotted Wilt Orthotospovirus (TSWV), along with the challenges in their management. These viruses have led to severe yield losses, sometimes causing complete crop failure due to their wide host range and the polyphagous nature of thrips. This further complicates control efforts by facilitating rapid spread across diverse crops and regions. The review highlights the multifaceted challenges in managing OV and thrips, including the lack of durable host resistance, limited diagnostic capabilities, and difficulties in controlling thrips populations. Current management strategies, including cultural practices, chemical control, biological control and resistant genotype development, have shown limited efficacy in providing long-term solutions. Recent advancements in biotechnological approaches, such as RNA interference, are discussed as promising pathways for improved virus management. The review underscores the need for genome editing techniques, such as CRISPR/Cas9, which offer the capacity to develop virus-resistant plants by targeting essential viral or vector genes to disrupt transmission cycles. Additionally, using nanoparticles for targeted delivery of antiviral compounds and novel detection tools presents another innovative solution to effectively mitigate the impact of OV on Indian agriculture.

The impact of preoperative renal insufficiency on the outcomes of patients with pancreatic cancer undergoing pancreaticoduodenectomy.

This study evaluated the impact of renal function impairment on long-term survival outcomes and adjuvant therapy in patients with pancreatic cancer undergoing pancreaticoduodenectomy (PD). In this study, 264 patients who underwent PD for pancreatic head cancer between 2011 and 2021 were retrospectively analyzed. The patients were subsequently categorized into three groups according to the estimated glomerular filtration rate: normal group (> 90 mL/min/1.73 m2, n = 73), moderate group (45-90 mL/min/1.73 m2, n = 176), and severe group (< 45 mL/min/1.73 m2, n = 15). The primary outcomes evaluated were postoperative complications, overall survival (OS), and relapse-free survival (RFS). Additionally, the completion of adjuvant therapy and risk factors for adjuvant therapy discontinuation were analyzed. The total proportion of patients with complications was significantly higher in the severe group (p = 0.008). The proportion of patients with severe complications (Clavien-Dindo classification ≥ IIIa) did not significantly differ between the chronic kidney disease (CKD) groups (p = 0.730). The proportion of patients in whom adjuvant therapy was completed was notably lower in the severe group (p = 0.011). Multiple logistic regression analysis revealed that CKD groups and hemoglobin levels ≤ 11.5g/dL were independent predictors of adjuvant therapy completion failure (p = 0.016 and p = 0.016). There was no significant difference in the OS and RFS rates between the CKD groups (p = 0.499, p = 0.688). In patients with pancreatic cancer and CKD, performing PD safely may be feasible; however, adjuvant therapy completion is challenging.

Detailed study of interphase degradation in SiC/BN/SiC ceramic matrix composites after elevated temperature tensile testing

Ceramic matrix composites of silicon carbide fibres in a silicon carbide matrix with boron nitride interphase are promising candidates for replacing superalloys in the hottest part of aerospace engines, reducing the need for cooling and increasing the fuel efficiency. This needs a thorough understanding of how these materials degrade under high levels of stress combined with high temperatures in an oxidative environment. This work presents a detailed investigation of the degradation in the interphase and surrounding interfaces. Advanced electron microscopy and electron energy loss spectroscopy are used to extract information on the degradation process. It was found that silica and boria form along with a migration of silica into the interphase. At 1000 °C the degradation along the surface leads to early fracture at the surface and eventually complete fracture of the composite, lower temperature allows for the oxidation to reach the centre of the sample before complete failure.

Dynamic tensile behaviors and crack propagation in fiber-reinforced cementitious composites: Experimental investigation and Peridynamic simulation

Fiber-Reinforced Cementitious Composites (FRCC) have gained significant attention in engineering applications due to their superior mechanical properties and toughness, particularly under high strain rate conditions. This study performed dynamic tensile tests on FRCC at high strain rates (35-110 s⁻¹) using a Split Hopkinson Tensile Bar (SHTB) apparatus. Additionally, a novel Peridynamic (PD) model was developed for the SHTB and FRCC system, leveraging the advanced capabilities of the emerging PD theory. The study compared and analyzed dynamic tensile strength, ultimate tensile strain, strain rate effects, failure modes, and crack development in FRCC with different fiber ratios at various high strain rates, using both experimental data and PD simulations. The results show that the PD-SHTB-FRCC dynamic model developed in this study exhibits high consistency between numerical simulations and experimental findings, effectively capturing the processes of crack initiation, propagation, and complete failure in FRCC specimens. The dynamic tensile properties of FRCC improve significantly with increased strain rates, with polyethylene (PE) fibers providing superior reinforcement compared to steel fibers. Notably, the dynamic tensile strength, peak tensile stress, and ultimate tensile strain of FRCC increase significantly with rising strain rates, with specimens containing higher PE fiber content showing a more pronounced enhancement effect. For strain rates between 42.6 s⁻¹ and 76.1 s⁻¹, considering dynamic tensile strength, ultimate tensile strain, and peak tensile stress, the optimal combination for resisting dynamic tensile loads was 1.5% PE fibers and 0.5% steel fibers. At a strain rate of 99.8 s⁻¹, a 2% PE fiber ratio alone provided the best performance.

Body Habitus vs. Hepatic Steatosis: Understanding the Drivers of Non-Diagnostic Shear Wave Elastography

PurposeShear Wave Elastography (SWE) is frequently non-diagnostic in obese patients, a key cohort at risk for liver disease. Subcutaneous fat and hepatic steatosis are suspected drivers, but their relative contribution is unknown. We compare ultrasound-guided attenuation parameter (UGAP), a marker of steatosis, body mass index (BMI), and skin-to-liver capsule distance (SCD) to predict non-diagnostic SWE. Materials and MethodsThis IRB approved, single center retrospective study included adults with SWE and diagnostic UGAP exams between June and December 2023. Fasting patients were imaged in supine position with right arm abducted, via an intercostal window during neutral breath hold. The median of 10 measurements in the right lobe was analyzed for SWE and UGAP. SWE measurements were ≥ 2 cm from the capsule while UGAP depth was fixed at 4 cm from the probe. Exams were considered non-diagnostic for SWE (measured in m/s) if the Interquartile Range/Median Ratio (IQR/M) was > 15% or if diagnostic measurements could not be obtained. UGAP IQR/M > 30% or complete measurement failure was considered non-diagnostic. Univariate Receiver Operating Characteristic (ROC) curves compared UGAP (dB/cm/MHz), BMI (kg/m2), and SCD (mm) prediction of non-diagnostic SWE by the DeLong test. Results87 participants (48 male) with mean age of 54.7 ± 15.7 years were analyzed. UGAP [OR: 1.63 per 0.1 dB/cm/MHz, p=0.02, AUC=0.66], BMI [OR: 1.23, p<0.001, AUC=0.77], and SCD [OR: 1.27, p<0.001, AUC=0.81) were predictors of non-diagnostic SWE. UGAP prediction of non-diagnostic SWE was similar in subgroups with the measurement region at least 1 cm (OR: 1.64, n = 68), and 2 cm (OR: 1.54, n = 16) from the liver capsule. UGAP was a worse predictor than SCD (p = 0.04), while not significantly different than BMI (p = 0.15). BMI and SCD did not differ in predicting non-diagnostic SWE (p = 0.44). ConclusionOur small preliminary study demonstrated that body habitus and hepatic attenuation, a marker of steatosis, both contribute to non-diagnostic SWE exams, however body wall thickness is the key driver. This informs patient selection for SWE exams and guides future research to mitigate these technical shortcomings. Clinical Relevance/ApplicationPatients with hepatic steatosis and large body habitus are at increased risk of non-diagnostic ultrasound shear wave elastography (SWE) exams. These patients, particularly those with increased body wall thickness, may benefit from liver fibrosis evaluation with alternative approaches following an initial non-diagnostic SWE exam. Researchers working to improve SWE technique should pay particular attention to mitigating attenuation and phase aberration from the body wall as this is the key driver of non-diagnostic exams.

Blast response and protection level of concrete composite wall panels made with recycled tyre fibres in a cement matrix

This paper investigates the blast response and protection level of a new blast-resistance wall panels made of Recycled Tyre Fibres Concrete (RTFC) as an exterior protective layer compositely connected to a concrete wall through experiments and numerical modelling. RTFC is a novel sustainable cement-based versatile composite, made with recycled non-biodegradable material (tyre rubber particles) in the form of composite fibres in a cement matrix, with applications in blast and ballistic protection that features high dynamic properties. Three composite wall panels were constructed and subjected to blast loads generated by Advanced Blast Simulator (ABS). Three different loading scenarios, each with an intensity capable of causing complete structural failure, were applied. The blast wave characteristics, such as the imposed overpressure and impulse, were measured alongside the deflection of the specimens. The wall specimens could withstand the blast loads with minimal damage. No cracks were observed in the RTFC layer, with only minor cracks appearing on the concrete side of the wall. The protection performance of the wall specimens was examined following UFC guidelines, revealing their outstanding resistance to blast loads. Moreover, in line with these guidelines, the composite wall panel is eligible for a High Level of Protection (HLoP) classification. Finally, a Single Degree of Freedom (SDOF) analytical model was developed for the wall panel to determine the Dynamic Increase Factor (DIF) of RTFC. The analysis resulted in a DIF value of 1.5, which was then incorporated into the numerical models of the walls. The accuracy of the DIF was validated by comparing the numerical results with experimental data, confirming its reliability.

A sensorless approach for cable failure detection and identification in cable-driven parallel robots

Cable-driven parallel robots (CDPRs) are a particular class of parallel robots that provide several advantages that may well be received in the industrial field. However, the risk of damage due to cable failure is not negligible, thus procedures that move the end-effector to a safe pose after failure are required. This work aims to provide a sensorless failure detection and identification strategy to properly recognize the cable failure event without adding additional devices. This approach is paired with an end-effector recovery strategy to move the end-effector towards a safe position, thus providing for a complete cable failure recovery strategy, which detects the failure event and controls the end-effector accordingly. The proposed strategy is tested on a cable-driven suspended parallel robot prototype composed of industrial-grade components. The experimental results show the feasibility of the proposed approach.

Experimental Investigation on Rock Failure Characteristics of Large-Span Goafs Using Digital Image Correlation Analysis and Acoustic Emission Monitoring

Rockmass in deep mining is highly susceptible to large-scale collapses under high stress and blast-induced disturbances, leading to casualties and economic losses. To investigate the evolution characteristics of goaf instability and the types of seismic sources that induce instability, an experiment on goaf instability was designed under uniaxial compression conditions based on actual mining operations. The entire experimental process was monitored using digital image correlation analysis and acoustic emission monitoring. By calculating the digital speckle field on the surface of the rock specimen during the experiment, the evolution characteristics of the deformation and strain fields from the beginning of loading to complete failure were analyzed. The study explored the dynamic behavior of cracks from initiation to propagation and eventually inducing large-scale collapse. The results show that the instability process of the goaf begins with the formation of tensile cracks. As stress increases, shear cracks occur in the specimen, leading to macroscopic failure. Furthermore, based on the differences in overall microfracture types measured by RA-AF characteristic parameters during specimen failure, large amplitude acoustic emission events corresponding to the formation of dominant macroscopic cracks were selected, and the focal mechanisms of these events were inverted. The results indicate that shear failure sources are significantly more prevalent than tensile failure sources in acoustic emission events leading to goaf instability. These findings can provide useful guidance for the support design and the prevention and control of rockmass instability disasters.

Improving solar panel performance using MPPT optimization algorithms

One of the primary challenges faced by solar energy systems is the issue of inconsistent lighting and uneven distribution of sunlight across the surface of solar panels. These conditions can result in a substantial reduction in the power output of the panels and, in some cases, the complete failure of certain solar cells. This paper examines the effects of shading on solar panel performance, focusing on how partial shading impacts energy production and efficiency through both experimental analysis and simulation. The findings emphasize the critical influence of shading patterns and configurations on the overall efficiency of photovoltaic systems. The study highlights the necessity of implementing shading mitigation strategies and optimization algorithms to enhance energy production and ensure the reliability of solar systems operating in environments with varying light conditions. This study showed that the use of optimization algorithms in photovoltaic systems exposed to shading increases their efficiency in terms of energy saving as well as performance stability. The simulation results shows that the GWO algorithm gives a higher performance than the other algorithms in the same partial shading conditions.

The Immediate Partial Removal of Cumulus-Oocyte Complexes: A Refined Approach for Rapid Observation of In Vitro Fertilization.

Despite the rapid advancements in clinical and laboratory technologies for in vitro fertilization (IVF), a significant proportion (10%-15%) of patients continue to experience fertilization disorders, leading to low fertilization rates and the production of nonviable embryos. Short-term fertilization involves the early removal of granulosa cells to observe the extrusion of the second polar body, enabling the assessment of fertilization and early remedial measures to address low fertilization rates and complete fertilization failure. However, the observation of short-term fertilization in IVF is impeded by challenges such as excessively large unprocessed clusters of cumulus-oocyte complexes and adhesion between eggs, necessitating complex external procedures for granulosa cell removal, and prolonged observation duration. To tackle this issue, this study proposes a method of immediate partial removal of granulosa cells post egg retrieval. This approach streamlines subsequent stages of short-term fertilization and traditional fertilization monitoring, reduces the time needed for oocyte extrusion, minimizes the likelihood of external environmental impacts on the oocytes, and decreases the risk of missing the critical fertilization observation window. Consequently, the study yields novel clinical evidence aimed at enhancing the operational efficiency of embryonic laboratories in IVF.

Preparation and properties of silica isophorone diisocyanate microcapsules for self-healing anticorrosive coatings

ABSTRACT Traditional anticorrosion coatings often suffer from reduced effectiveness or even complete failure due to the formation of microcracks. Isophorone diisocyanate (IPDI) can form a polyurea structure without a catalyst in the presence of water, which can protect the underlying metal from corrosion. In this study, an anticorrosion coating with self-healing properties was developed by incorporating microcapsules containing IPDI into the coating formulation. Silica-based self-healing microcapsules were synthesized via interfacial polymerization, using tetraethyl orthosilicate as the precursor and IPDI as the core material. The effects of core-to-wall ratio, reaction temperature, different emulsifiers, and emulsifier ratios on the microcapsule properties were investigated. The results demonstrated that microcapsules prepared using a composite emulsifier system of cetyltrimethylammonium bromide (CTAB) and OP-10 at a 1:1 ratio, with a core-to-wall ratio of 1:1, and a reaction temperature of 75°C, exhibited a smooth surface, spherical shape, and excellent encapsulation efficiency. The maximum core content achieved was 81.2 wt%. An epoxy coating embedded with these self-healing microcapsules was subjected to scratching damage. After applying water to the surface and allowing it to stand for 2 days, the scratches healed, and the steel plate surface remained free from corrosion, indicating excellent self-healing performance.

Strain-softening model for granite and sandstone based on experimental and discrete element methods

Combing macroscopic experimental method and mesoscopic numerical method, this study analyses the strain-softening behaviours of granite and sandstone. From the macroscopic perspective, the stress–strain curves of granite and sandstone under different confining pressures are studied by laboratory triaxial compression test. Variations of post-peak reduction modulus and critical plastic shear strain versus confining stress are obtained. Evolution of strength parameters at peak, residual and strain-softening stage are proposed. Then a method to develop the strain-softening model of hard and soft rocks is presented. From the mesoscopic perspective, based on the laboratory test results, the parameters of discrete element method PFC for the samples of the granite and sandstone are calibrated. Comparing the basically consistent results of laboratory experiment and numerical simulation, the feasibility of discrete element method is verified. Evolutions of mesoscopic crack propagation and mesoscopic particle displacement field in the complete failure process are analysed. Typical stresses of granite sample and sandstone sample in the failure stage are investigated. Above combined macroscopic experimental method and mesoscopic numerical method systematically analyse the characteristics of hard rock and soft rock in the strain-softening stage. Failure process and mechanical property of hard rock and soft rock are revealed at the macroscopic and mesoscopic levels. The initiation and propagation process of micro-cracks in rock are thoroughly investigated. The research results provide a scientific foundation for the analyse of strain-softening behaviour of hard rock and soft rock. The result shows that both the mesoscopic numerical method and macroscopic experimental method indicate that the failure pattern of sandstone is influenced by both confining pressure and axial stress, while granite is mainly affected by axial stress.

Thermodynamics-driven metabolic and microbial preference for lactate methanization at different operational temperatures

Lactate-dominant organic acids released from acidified feedstocks inhibit anaerobic digestion processes, which can result in decreased biomethane (CH4) yield or even complete process failure. Herein, this study focus on exploring the effects of temperature (35 °C, 38 °C, 41 °C, 44 °C, 47 °C, 50 °C, and 55 °C) on the thermodynamics of microbial communities to assess the thermodynamics or microbial flora in driving the concurrent bioreactions involved in organic acid degradation. The findings revealed a prevalence of species such as Syntrophaceticus schinkii, DTU014, and Methanosarcina at 38 °C-44 °C. These species are known for their abilities in propionate and butyrate degradations, acetate oxidation, and methanation, respectively. Conversely, at thermophilic temperatures (47 °C, 50 °C, and 55 °C), this study observed higher abundance of thermophilic microorganisms like Defluviitoga and Methanoculleus, although these organisms are adapted to higher temperatures, their lactate utilization and methane production were less efficient than mesophilic species. Despite higher ΔG values for lactate, propionate, and butyrate degradation at 38 °C–44 °C compared with thermophilic temperatures, the relative abundance of functional enzymes (specifically, propionate and butyrate degrading enzymes) was found to be marginally higher than 47 °C–55 °C. As a result, 41 °C–44 °C induced remarkable thermodynamic effects that not only facilitated organic acid degradation but also promoted subsequent methanation, indicating the suitability of these temperatures for the methanation of biowaste acidified by lactate. Overall, this study provides insight into the temperature-dependent response of organic acid degradation, specifically focusing on the mechanisms involved in overcoming energy barriers, shaping the microbial flora, and ultimately improving the efficiency and stability of anaerobic digestion, especially for lactate-acidified feedstock.

Bionic Design of High-Performance Joints: Differences in Failure Mechanisms Caused by the Different Structures of Beetle Femur-Tibial Joints.

Beetle femur-tibial joints can bear large loads, and the joint structure plays a crucial role. Differences in living habits will lead to differences in femur-tibial joint structure, resulting in different mechanical properties. Here, we determined the structural characteristics of the femur-tibial joints of three species of beetles with different living habits. The tibia of Scarabaeidae Protaetia brevitarsis and Cetoniidae Torynorrhina fulvopilosa slide through cashew-shaped bumps on both sides of the femur in a guide rail consisting of a ring and a cone bump. The femur-tibial joint of Buprestidae Chrysodema radians is composed of a conical convex tibia and a circular concave femur. A bionic structure design was developed out based on the characteristics of the structure of the femur-tibial joints. Differences in the failure of different joint models were obtained through experiments and finite element analysis. The experimental results show that although the spherical connection model can bear low loads, it can maintain partial integrity of the structure and avoid complete failure. The cuboid connection model shows a higher load-bearing capacity, but its failure mode is irreversible deformation. As key parts of rotatable mechanisms, the bionic models have the potential for wide application in the high-load engineering field.

Fathomless Ocean of Objectivity, Death, and Memory

Stanislaw Lem's 1961 sci-fi classic Solaris features one of the most enduring, strange, and seemingly inexhaustible presentments of the concept of an ocean. Lem’s economy of craft resonantly renders the premise of the text on the idea that there are inescapable ontological gaps between objects encountering one another. Using immense detail, and a scientific, specifically historiographic, naturalist, and philosophical style of prose, Lem frames this idea as the complete failure of human beings to understand an extraterrestrial intelligence. The narrative follows a team of terrestrial scientists as they attempt to probe, examine, and communicate with the oceanic surface of the planet Solaris from a research station hovering above it. Based on years of research and study, the Solarists deduce that the planet, through its oceanic membrane, can somehow manifest the ability to (re)produce human secrets and guilt into material form. That form, which physically appears on the station and confronts its crew, is dependent on the specific consciousnesses of each scientist aboard. The research of the Solarists also reveals that any human attempt to formalize and concretize the phenomenological occurrences of the ocean that 'make sense' always fail. For Lem, “[t]he peculiarity of those phenomena seems to suggest that we observe a kind of rational activity, but the meaning of this seemingly rational activity of the Solarian ocean is beyond the reach of human beings” (Lem 1989). As a type of 'memory-machine', Lem's ocean seems to act as some kind of psycho-emotional repository in which and from which various psycho-emotional affects are repressed, restored, and reproduced. Because of the radical indeterminacy of human understandings of the ocean, it is difficult if not impossible to say “why” the Solaris ocean does what it does, to attribute to its processes anything intentional, or to ascribe any anthropocentric teleology or technology to its phenomena and processes. While critics have applied numerous, and typically psychoanalytically-informed readings of the Solaris ocean, such a move subjectivizes the ocean at the expense of the seemingly inexhaustible and interesting aspects of its objectivity (its status as an object). An object oriented approach allows us to better tease these out, and open up the depths of alienness and familiarity that, while ostensibly akin to the psycho-emotional trenches of the human unconscious, are externalized in the form of a truly strange object which in turn (re)produces truly strange objects. In view of the above, this paper seeks to accomplish the following: 1) to assert that an object oriented approach will offer better footing from which to prosecute any reading concerning the Solaris ocean's relationship with trauma and opportunity, (re)exposure, and healing; 2) offer a Post-romantic, object oriented analysis of Lem's well-crafted, detailed representation of radical alienness through the paradoxically concrete, albeit also radically indeterminate, image of an ocean-like entity/superstructure/hyperobject/space; 3) explore the encounters between the oceanic space with both human actors and the technology that mediates said interaction.

Persistent Vetal Vasculature-Vitreoretinal Surgery

Persistent fetal vasculature (PFV), previously known as persistent hyperplastic primary vitreous (PHPV), is a spectrum of congenital anomalies caused by complete or partial failure of the fetal hyaloid vasculature to regress. The severity of the disease may vary depending on the affected intraocular structures and anatomical variations. The outcomes of surgery depend on the type, location, extent, and severity of the disease. The aim of this review is to focus on surgical indications and techniques, and the prognosis of PFV in the current literature and our clinical experience.

Life stage-specific effects of heat stress on spermatogenesis and oogenesis in Drosophila melanogaster.

Biodiversity is increasingly threatened by unpredictable, frequent, and intense climatic events like heatwaves that pose harmful impacts on ectotherms. Beyond the health and survival of organisms, reduced reproductive performance has emerged as a critical fitness consequence of thermal stress induced by high temperatures. Many studies on these effects expose organisms to heat stress during the adult stage or throughout development, often focusing on cumulative effects across life stages, and they tend to examine one or the other sex. This approach may not reflect the short-term nature of many extreme heat events and limits our understanding of stage- and sex-specific fitness consequences in short-lived organisms. To address this gap, we used Drosophila melanogaster to investigate the sex-specific reproductive performance following short heat stress of varying intensity at different developmental stages. We found the thermal sensitivity to be higher in males than females, and to increase toward adult emergence, leading to nearly complete reproductive failure and substantially slowed recovery. These results highlight how even brief bouts of heat stress during a sensitive phase could affect population dynamics and persistence. Our findings also underscore that incorporating both sex and life stage could improve predictions of species persistence.

Systematic Review of the Profunda Artery Perforator Free Flap for Head and Neck Reconstruction.

The profunda artery perforator (PAP) flap has gained popularity in head and neck reconstruction with a favorable donor site providing a relatively hidden scar and the ability to harvest a large amount of pliable tissue with consistent vascular anatomy. The primary aim of this study is to evaluate the safety and efficacy of this PAP flap in head and neck reconstruction. PUBMED, EMBASE, Web of Science, Google Scholar (January 1948-February 2022). A systematic review of the English language literature was conducted for studies with at least 3 patients 18 years or older undergoing head and neck reconstruction utilizing the PAP. Study quality and risk of bias were evaluated using the MINORS scoring system. Main analysis endpoints were flap failure rate, donor site morbidity, and complication rate. Nine articles and 206 total PAP flaps were included. The rate of flap-related and medical complications was 33%, with only 2 (0.97%) instances of complete flap failure. Other complications included partial flap failure (10, 4.86%) and donor site wound complications (12, 5.83%). A total of 16 flaps (7.77%) required subsequent revision in the operating room. Average MINORS score of the studies suggested a moderate to high risk of bias. Based on limited quality evidence, this review suggests that the PAP flap is a safe and feasible tool for head and neck reconstruction, with comparable complication and success rates as other free flaps. Further large-scale studies are warranted.

Extreme Space Weather Impacts on GNSS Timing Signals for Electricity Grid Management

AbstractExtreme space weather events can have serious impacts on critical infrastructure, including Global Navigation Satellite Systems (GNSS). The use of GNSS, particularly as sources of accurate timing signals, is becoming more widespread, with one example being the measurement of electricity grid frequency and phase information to aid grid management and stability. Understanding the likelihood of extreme space weather impacts on GNSS timing signals is therefore becoming vital to maintain national electricity grid resilience. This study determines critical intensity thresholds above which the complete failure of a GNSS based timing system may occur. Solar radio bursts are identified as a simple example to investigate in more detail. The probability of occurrence of an extreme space weather event with an intensity equal to or greater than the critical intensity is estimated. Both a power law and extreme value theory were used to evaluate recurrence probabilities based on historical event frequencies. The probability was estimated to be between 3%–12% per decade to cause the complete failure of any GNSS‐based timing system.