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Impact of negative biased current on memristive sensor response to chemical exposure
No full textThe rapid advancement of emerging technologies necessitates next-generation gas sensor systems that are compact, energy-efficient, and highly sensitive. Among the most promising approaches, memristor-based gas sensors, or gasistors, have attracted significant attention due to their ultra-lightweight structure, fast recovery time, and efficient miniaturization. This paper provides a comprehensive review of gasistor technology, integrating both simulation models and experimental investigations. The simulation analysis focuses on memristor characteristics, offering insight into composite gas detection strategies, while experimental evaluations assess key performance metrics. In addition, advanced recovery methodologies, such as pulse and trigger-based techniques, are explored to improve sensor performance. The concluding discussion outlines future perspectives and challenges in memristor development, emphasizing their potential for integration into next-generation sensing platforms
Improving the load-carrying capacity of structures consisting of multiple elements
Get PDFThe paper presents a very powerful method in structural engineering, referred to as the method of aggregation, for reducing the weight and increasing load capacity of structures. Rigorous results have been stated and proved, forming the foundation of the aggregation method for structures composed of beams with arbitrarily shaped cross-sections. The essence of this method, overlooked in modern stress analysis, lies in consolidating loaded elements into a reduced number of elements with larger cross-sections, thereby significantly decreasing the material required to support a given total load. For instance, in a five-to-one aggregation of cantilever and simply supported beams, material usage can be reduced by a factor of 1.71. For cantilever and simply supported beams, the reduction in material volume, deflection, and stress depends only on the scaling factor of the cross-section along the y-axis and is independent of the scaling factor along the x-axis. The aggregation method was tested by a case study and finite element experiments involving structures built on statically determinate cantilever beams and statically indeterminate portal frames. These studies confirmed that aggregating elements loaded in bending leads to a drastic increase of the load capacity of the structures and a drastic decrease of both the maximum von Mises stress and the maximum deflection
Principles of arranging and managing adoption support services and therapies M3
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Entrepreneurial finance and the survival of equity-funded firms in crisis periods : the case of COVID-19
Get PDFThis study investigates the resilience of 13,786 UK entrepreneurial firms that received equity financing before COVID-19, with 653 becoming insolvent and 6254 securing guaranteed loans during the pandemic. Utilising the resource-based view (RBV) and signalling theories, we hypothesise that equity-backed firms have sufficient resources to withstand crises, varying by investor type and involvement. We compare the bankruptcy risk of these firms during COVID-19 to the pre-COVID period, considering investor type, deal history and financial and non-financial factors. Results show similar insolvency rates during COVID-19 compared to pre-COVID, but firms backed by active investors are less likely to become insolvent during crises. We examine the characteristics of loan recipients, financing combinations and insolvency risk, finding that companies using COVID loans were generally more prone to insolvency, except those backed by active investor types. Our findings offer insights into the role of equity financing across various investor types in venture survival during crises, with policy implications
Governing migration, producing skills : emigration and education in the Philippines
Get PDFThis article examines skill as an integral yet understudied aspect of emigration governance. To date, migration studies have mainly focused on how the demand for migrant skills drive people’s movements across borders, shaping the conditions for entry into popular destinations in the West. In contrast, less is known as to how skills also shape the way governments manage emigration, pushing wouldbe migrants to acquire certain capacities well before they leave their countries of origin. Drawing from the case of the Philippines, this article discusses how state agencies have used skills training to dominate specific markets for migrant professionals and demand higher wages for Filipino workers abroad. Yet, this emphasis on skilling has also worsened existing inequalities within the country, creating social problems that state officials are unable to fully address and control. We argue that such issues stem from the private schools and training companies who dominate skills provision for aspiring migrants. Such actors remain largely overlooked in current scholarship, despite their increasing influence on workers’ migration trajectories. This paper highlights the challenges of producing workers for labor markets beyond borders, as well as its implications on how we understand migration governance as a whole
Treatments for MEN1-associated endocrine tumours : three systematic reviews and a meta-analysis
Get PDFBackground.
Multiple endocrine neoplasia type 1 (MEN1) is a rare hereditary disorder characterised by the combined occurrence of parathyroid, pancreatic, and pituitary tumours. Current treatments are based on very low-quality evidence. Our aims were to determine treatment outcomes in patients with MEN1 for: subtotal parathyroidectomy versus less than subtotal parathyroidectomy for primary hyperparathyroidism (Q1); surgery versus active surveillance for non-functioning pancreatic neuroendocrine tumours sized 2 cm or less (Q2); and dopamine agonist responses of prolactinomas in patients with MEN1 versus patients without MEN1 (Q3).
Methods.
We conducted three systematic reviews and one meta-analysis. Four electronic databases (MEDLINE Ovid, Embase Ovid, The Cochrane Library, and Web of Science) were searched from Dec 1, 2001, to Feb 13, 2023, with no language restrictions. Study designs included randomised controlled trials, prospective and retrospective cohort studies, and case-controlled and case series. Adults and children with MEN1-associated tumours were included in all three systematic reviews. For each clinical question, three pairs of authors independently screened abstracts and assessed the full text for final inclusion, discordant views were resolved by senior authors. Dichotomous outcomes were calculated using risk ratios or hazard ratios for time-to-event analyses, with 95% CIs. Continuous outcomes were ascertained using mean difference with 95% CIs. Where feasible, outcomes from individual studies were analysed through meta-analysis, using a random-effects model. The systematic reviews were prospectively registered (PROSPERO reference numbers CRD42023409912, CRD42023409936, and CRD42023409949).
Findings.
For primary hyperparathyroidism (Q1), 990 non-duplicate records were screened for title and abstract, of which 23 studies with 1073 patients were eligible for meta-analysis. These studies showed that subtotal parathyroidectomy had a significantly lower risk of persistent primary hyperparathyroidism (RR 0·32, 95% CI 0·20–0·52; I²=0%) and recurrent primary hyperparathyroidism (RR 0·78, 0·62–0·97; I²=27%), when compared with less than subtotal parathyroidectomy, although the risk of post-operative hypoparathyroidism was higher (RR 2·64, 1·63–4·29; I²=0%). For non-functioning pancreatic neuroendocrine tumours sized 2 cm and less (Q2), 1583 non-duplicate records were screened for title and abstract, of which three cohort studies were eligible for analysis. These studies showed that combined metastatic disease and mortality rates were comparable between patients in the surgery group (two [7%] of 27 to three [20%] of 15) and patients in the active surveillance group (one [3%] of 33 to four [8%] of 50]). For prolactinomas (Q3), 475 non-duplicate records were screened for title and abstract, of which ten studies with 505 patients were eligible for analysis. These studies showed that dopamine agonist treatment failure rates to normalise serum prolactin were similar between patients with MEN1 (zero of one to one [33%] of three) and patients without MEN1 (four [6%] of 68 to nine (82%) of 11), n=23 studies). GRADE certainty scores for all were low or very low.
Interpretation.
In patients with MEN1, subtotal parathyroidectomy achieved greater reductions in persistence and recurrence of primary hyperparathyroidism than less than subtotal parathyroidectomy; for non-functioning pancreatic neuroendocrine tumours sized 2 cm or less, the few available studies suggest that active surveillance might be comparable to surgical resection; and for prolactinomas, dopamine agonist therapy appears to have comparable efficacy as in patients without MEN1.
Funding: None
Plant NETWORKED and VAP27 proteins work in complexes to regulate membrane-based functions
Get PDFEukaryotic cells are subdivided into specialised organelle compartments, each with unique physiological environments and functions. Interaction and cross-talk between organelles is inherent to Eukaryotic life, and each organelle is physically interconnected to their surrounding subcellular components including the cytoskeleton and adjacent membrane compartments. In animals and yeast, the mechanisms of organelle interaction have been well characterised and are known to have fundamental importance to life. In contrast, we are only beginning to understand the mechanisms and functions of such interactions in plants. The discovery and ongoing characterisation of the NETWORKED (NET) protein family of plant actin-membrane adaptors has greatly advanced our understanding of the mechanisms of organelle-cytoskeletal interaction. Furthermore, unfolding investigation into the NET proteins has revealed their binding partner, VAMP-ASSOCIATED PROTEIN-27 (VAP27), to be a regulator of organelle tethering and interaction with previously unknown, specialised roles in plants. Research on NET and VAP27 proteins has rapidly increased our knowledge of the mechanisms regulating membrane interaction in plants, their functions in regulating cell structure and organisation, as well as their importance to plant growth, development and stress-response. Here, we discuss the discovery and characterisation of the NET and VAP27 proteins, their regulation of organelle interaction and their functions in plants
Bioinspired dampers : meniscus-inspired energy dissipation components
Get PDFNature provides examples of functionally graded porous structures that absorb energy effectively, such as the knee meniscus. The meniscus features a three-layered structure with varying porosity from the outer to inner layers. The tissue's porous spaces are fluid-saturated, facilitating energy dissipation and damping. Inspired by this architecture, two 3-layered porous geometries were designed, which consisted of thin outer layers and a thicker inner layer with higher porosity and permeability. They were created using image analysis (IA), computational fluid dynamics (CFD) simulations, and pore space segmentation (PSS). The PSS geometry shows a reduced peak pore diameter (88μm vs 111μm) and an increased density of lower throat lengths but a slightly larger throat radius compared to the CFD geometry. These differences significantly impact permeability, with PSS samples showing a peak of 1522 D versus 151 D in CFD samples. Energy dissipation capabilities were evaluated through cyclic compression experiments at varying rates and with different fluid viscosities. The dissipation energy density of the CFD geometry (1.8kPa) was 2.5 times higher than that of the PSS geometry (0.7kPa). Scanning Electron Microscopy (SEM) compression tests revealed deformation patterns, including crease formation, bulging, and permanent deformation
