Search Results (21)

With the continuous development of new aircraft, the application of low-cost composite materials technology still encounters numerous challenges and issues. The development of low-cost composite technology, while ensuring the high reliability of aircraft components, has become a common concern among aerospace composites. The research presented in this paper examines the findings related to the conformity verification process of an electric aircraft in China. This is an all-composite structural general aviation aircraft certified under CCAR Part 23. This study focuses on the quality characteristics of low-cost wet vacuum bagging composites, addressing the causes and effects of high porosity in the manufacturing process. Based on the research findings, a relationship between porosity and the strength of wet vacuum bagging composites is established. Consequently, a safe and reliable method for ensuring airworthiness conformity of low-cost composites is proposed and implemented in the aircraft type’s conformity verification. Furthermore, this paper discusses the development trends of low-cost composites for general aviation, providing valuable insights for the advancement of low-cost technologies in the future. Full article

The aim of this study was to assess the applicability of the Mechanical Systems Coordination Working Group’s (MSCWG) findings, based on FAR 25.831(g), to Chinese pilots through a human physiological experiment conducted in a high-temperature environment to investigate the effects of core temperature. Methods: A controlled experiment was carried out in a high-temperature environment simulation room involving a cohort of healthy males aged 18–50 years. Wireless physiological monitoring equipment and a neurobehavioral assessment system were utilized to track changes in physiological parameters and neurobehavioral responses at varying core temperatures and time intervals. Results: There was a significant increase in human core body temperature, skin temperature, and heart rate as the ambient temperature rose, all remaining within acceptable physiological limits. Although arterial and venous oxygen saturation decreased with increasing ambient temperature, the difference was not statistically significant. The neurobehavioral abilities of the subjects did not exhibit notable changes across different core temperature–time conditions. Conclusions: The core temperature limits set forth by the MSCWG have been shown to have a safe impact on the physiological and behavioral aspects of Chinese pilots, which can be used as an equivalent safety regulation for airworthiness compliance validation under CCAR 25.831(g). Limitation: The present study was constrained to a male sample, it did not thoroughly explore female responses, and it had a small sample size (10 per group). The latter two factors may have affected the statistical validity and generalizability of the results. Full article

Clavulanic acid is a potent β-lactamase inhibitor produced by Streptomyces clavuligerus, widely used in combination with β-lactam antibiotics to combat antimicrobial resistance. This systematic review analyzes the most successful methodologies for clavulanic acid overproduction, focusing on the highest yields reported in bench-scale and bioreactor-scale fermentations. Studies have demonstrated that glycerol is the preferred carbon source for clavulanic acid production over other sources like starch and dextrins. The optimization of feeding strategies, especially in fed-batch operations, has improved glycerol utilization and extended the clavulanic acid production phase. Organic nitrogen sources, particularly soybean protein isolates and amino acid supplements such as L-arginine, L-threonine, and L-glutamate, have been proven effective at increasing CA yields both in batch and fed-batch cultures, especially when balanced with appropriate carbon sources. Strain engineering approaches, including mutagenesis and targeted genetic modifications, have allowed for the obtainment of overproducer S. clavuligerus strains. Specifically, engineering efforts that overexpress key regulatory genes such as ccaR and claR, or that disrupt competing pathways, redirect the metabolic flux towards CA biosynthesis, leading to high clavulanic acid titers. The fed-batch operation at the bioreactor scale emerges as the most feasible alternative for prolonged clavulanic acid production with both wild-type and mutant strains, allowing for the attainment of high titers during cultivations. Full article

A fire in the cargo compartment has a major impact on civil aviation flight safety, and according to the airworthiness clause of the CCAR-25, the detector must sound an alarm within 1 min of a fire in the cargo compartment. As for the cargo compartment of large transport aircrafts, the internal space is high and open, and the smoke movement speed becomes slower with significant cooling in the process of diffusion. Hysteresis can occur in smoke detectors because of their internal labyrinth structure, which causes the detector’s internal and external response signals to be out of sync. This research employs a numerical simulation to examine the detector response parameters under an ambient wind speed of 0.1–0.2 m/s and fits a Cleary two-stage hysteresis model, where τ₁= 0.09u^−1.43 and τ₂= 0.67u^−1.59. Finally, multiple full-scale cargo cabin experiments were conducted to validate the prediction model. The results show that the model’s predicted alarm range is 43.1 s to 49.0 s, and the actual alarm time obtained by the experiment falls within this interval, confirming the model’s accuracy and providing theoretical support for the structural design and layout of the aircraft cargo cabin smoke detector. Full article

Determining the criticality of ice shapes is a necessary condition for verifying compliance with icing airworthiness regulations. However, the clear, concise, and applicable criterion based on the geometric characteristics of ice shapes has not been clearly given out by current advisory circulars. To address this problem, this paper summarizes aerodynamic performance items and recommended ice shapes the latest version of CCAR-25 and corresponding advisory circulars for a variety of flight phases, including takeoff, holding, en route, DTO, etc., instead of the single phase of holding in the previous research. Based on the geometric classification of the ice shapes, the dominant parameters of various ice shapes are clarified by the correlation between the geometric parameters and aerodynamic effects. The geometric parameters to determine the criticality of specific ice shapes are defined as the roughness height and range for the roughness ice and the total projection height in the direction of lift for the horn ice. On this basis, the detailed determination criterion of critical ice shape geometries corresponding to different flight phases and aircraft components is formulated, which will provide an operational selection methodology for determining the geometries of critical ice shapes at the airworthiness certification stage. Full article

Papillomaviruses (PV) infect epithelial cells and can cause hyperplastic or neoplastic lesions. In felids, most described PVs are from domestic cats (Felis catus; n = 7 types), with one type identified in each of the five wild felid species studied to date (Panthera uncia, Puma concolor, Leopardus wiedii, Panthera leo persica and Lynx rufus). PVs from domestic cats are highly diverse and are currently classified into three genera (Lambdapapillomavirus, Dyothetapapillomavirus, and Taupapillomavirus), whereas those from wild felids, although diverse, are all classified into the Lambdapapillomavirus genus. In this study, we used a metagenomic approach to identify ten novel PV genomes from rectal swabs of five deceased caracals (Caracal caracal) living in the greater Cape Town area, South Africa. These are the first PVs to be described from caracals, and represent six new PV types, i.e., Caracal caracal papillomavirus (CcarPV) 1–6. These CcarPV fall into two phylogenetically distinct genera: Lambdapapillomavirus, and Treisetapapillomavirus. Two or more PV types were identified in a single individual for three of the five caracals, and four caracals shared at least one of the same PV types with another caracal. This study broadens our understanding of wild felid PVs and provides evidence that there may be several wild felid PV lineages. Full article

The design of high-performance complementary meta-resonators for microwave sensors featuring high sensitivity and consistent evaluation of dielectric materials is challenging. This paper presents the design and implementation of a novel complementary resonator with high sensitivity for dielectric substrate characterization based on permittivity and thickness. A complementary crossed arrow resonator (CCAR) is proposed and integrated with a fifty-ohm microstrip transmission line. The CCAR’s distinct geometry, which consists of crossed arrow-shaped components, allows for the implementation of a resonator with exceptional sensitivity to changes in permittivity and thickness of the material under test (MUT). The CCAR’s geometrical parameters are optimized to resonate at 15 GHz. The CCAR sensor’s working principle is explained using a lumped-element equivalent circuit. The optimized CCAR sensor is fabricated using an LPKF protolaser on a 0.762-mm thick dielectric substrate AD250C. The MUTs with dielectric permittivity ranging from 2.5 to 10.2 and thickness ranging from 0.5 mm to 1.9 mm are used to investigate the properties and calibrate the proposed CCAR sensor. A two-dimensional calibration surface is developed using an inverse regression modelling approach to ensure precise and reliable measurements. The proposed CCAR sensor is distinguished by its high sensitivity of 5.74%, low fabrication cost, and enhanced performance compared to state-of-the-art designs, making it a versatile instrument for dielectric characterization. Full article

The vast majority of transcribed RNAs are noncoding RNAs. Among noncoding RNAs, long noncoding RNAs (lncRNAs), which contain hundreds to thousands of bases, have received attention in many fields. The vast majority of the constituent cells in bone tissue are osteocytes, but their regulatory mechanisms are incompletely understood. Considering the wide range of potential contributions of lncRNAs to physiological processes and pathological conditions, we hypothesized that lncRNAs in osteocytes, which have not been reported, could be involved in bone metabolism. Here, we first isolated osteocytes from femurs of mice with osteocyte-specific GFP expression. Then, through RNA-sequencing, we identified osteocyte-specific lncRNAs and focused on a novel lncRNA, 9530026P05Rik (lncRNA953Rik), which strongly suppressed osteogenic differentiation. In the IDG-SW3 osteocyte line with lncRNA953Rik overexpression, the expression of Osterix and its downstream genes was reduced. RNA pull-down and subsequent LC-MS/MS analysis revealed that lncRNA953Rik bound the nuclear protein CCAR2. We demonstrated that CCAR2 promoted Wnt/β-catenin signaling and that lncRNA953Rik inhibited this pathway. lncRNA953Rik sequestered CCAR2 from HDAC1, leading to deacetylation of H3K27 in the Osterix promoter and consequent transcriptional downregulation of Osterix. This research is the first to clarify the role of a lncRNA in osteocytes. Our findings can pave the way for novel therapeutic options targeting lncRNAs in osteocytes to treat bone metabolic diseases such as osteoporosis. Full article

(1) Background: Activation of the receptor tyrosine kinase Axl by Gas6 fosters oncogenic effects in hepatocellular carcinoma (HCC), associating with increased mortality of patients. The impact of Gas6/Axl signaling on the induction of individual target genes in HCC and its consequences is an open issue. (2) Methods: RNA-seq analysis of Gas6-stimulated Axl-proficient or Axl-deficient HCC cells was used to identify Gas6/Axl targets. Gain- and loss-of-function studies as well as proteomics were employed to characterize the role of PRAME (preferentially expressed antigen in melanoma). Expression of Axl/PRAME was assessed in publicly available HCC patient datasets and in 133 HCC cases. (3) Results: Exploitation of well-characterized HCC models expressing Axl or devoid of Axl allowed the identification of target genes including PRAME. Intervention with Axl signaling or MAPK/ERK1/2 resulted in reduced PRAME expression. PRAME levels were associated with a mesenchymal-like phenotype augmenting 2D cell migration and 3D cell invasion. Interactions with pro-oncogenic proteins such as CCAR1 suggested further tumor-promoting functions of PRAME in HCC. Moreover, PRAME showed elevated expression in Axl-stratified HCC patients, which correlates with vascular invasion and lowered patient survival. (4) Conclusions: PRAME is a bona fide target of Gas6/Axl/ERK signaling linked to EMT and cancer cell invasion in HCC. Full article

Introduction: Laboratory data link cannabinoid exposure to chromosomal mis-segregation errors. Recent epidemiological reports confirm this link and raise concern that elevated chromosomal congenital anomaly rates (CCAR) may be occurring in Europe which is experiencing increased cannabis use, daily intensity of use and cannabinoid potency. Methods: CCAR data from Eurocat. Drug use data from the European Monitoring Centre for Drugs and Drug Addiction. Income from World Bank. Bivariate, multivariate, panel and geotemporospatial regressions analyzed. Inverse probability weighting of panel models and E-values used as major quantitative causal inferential methodologies. Results: In countries where daily cannabis use was rising the trend for CCA’s was upwards whereas in those where daily use was declining it was usually downwards (p = 0.0002). In inverse probability weighted panel models terms for cannabis metrics were significant for chromosomal disorders, trisomies 21 and 13 and Klinefelters syndrome from p < 2.2 × 10⁻¹⁶. In spatiotemporal models cannabis terms were positive and significant for chromosomal disorders, genetic disorders, trisomies 21, 18 and 13, Turners and Klinefelters syndromes from 4.28 × 10⁻⁶, 5.79 × 10⁻¹², 1.26 × 10⁻¹¹, 1.12 × 10⁻⁷, 7.52 × 10⁻⁹, 7.19 × 10⁻⁷ and 7.27 × 10⁻⁷. 83.7% of E-value estimates and 74.4% of minimum E-values (mEV) > 9 including four values each at infinity. Considering E-values: the sensitivity of the individual disorders was trisomy 13 > trisomy 21 > Klinefelters > chromosomal disorders > Turners > genetic syndromes > trisomy 18 with mEV’s 1.91 × 10²⁵ to 59.31; and daily cannabis use was the most powerful covariate (median mEV = 1.91 × 10²⁵). Conclusions: Data indicate that, consistent with reports from Hawaii, Canada, Colorado, Australia and USA, CCARs are causally and spatiotemporally related to metrics and intensity of cannabis exposure, directly impact 645 MB (21.5%) of the human genome and may implicate epigenomic-centrosomal mechanisms. Full article

A FBXW7 is an F-box E3 ubiquitin-ligase affecting cell growth by controlling protein degradation. Mechanistically, its effect on its substrates depends on the phosphorylation of degron motifs, but the abundance of these phosphodegrons has not been systematically explored. We used a ratiometric protein degradation assay geared towards the identification of FBXW7-binding degron motifs phosphorylated by mitogen-activated protein kinases (MAPKs). Most of the known FBXW7 targets are localized in the nucleus and function as transcription factors. Here, in addition to more transcription affecting factors (ETV5, KLF4, SP5, JAZF1, and ZMIZ1 CAMTA2), we identified phosphodegrons located in proteins involved in chromatin regulation (ARID4B, KMT2E, KMT2D, and KAT6B) or cytoskeletal regulation (MAP2, Myozenin-2, SMTL2, and AKAP11), and some other proteins with miscellaneous functions (EIF4G3, CDT1, and CCAR2). We show that the protein level of full-length ARID4B, ETV5, JAZF1, and ZMIZ1 are affected by different MAPKs since their FBXW7-mediated degradation was diminished in the presence of MAPK-specific inhibitors. Our results suggest that MAPK and FBXW7 partnership plays an important cellular role by directly affecting the level of key regulatory proteins. The data also suggest that the p38α-controlled phosphodegron in JAZF1 may be responsible for the pathological regulation of the cancer-related JAZF1-SUZ12 fusion construct implicated in endometrial stromal sarcoma. Full article

Several strategies, including inducer addition and biosensor use, have been developed for dynamical regulation. However, the toxicity, cost, and inflexibility of existing strategies have created a demand for superior technology. In this study, we designed an optogenetic dual-switch system and applied it to increase polyhydroxybutyrate (PHB) production. First, an optimized chromatic acclimation sensor/regulator (RBS10–CcaS#10–CcaR) system (comprising an optimized ribosomal binding site (RBS), light sensory protein CcaS, and response regulator CcaR) was selected for a wide sensing range of approximately 10-fold between green-light activation and red-light repression. The RBS10–CcaS#10–CcaR system was combined with a blue light-activated YF1–FixJ–PhlF system (containing histidine kinase YF1, response regulator FixJ, and repressor PhlF) engineered with reduced crosstalk. Finally, the optogenetic dual-switch system was used to rewire the metabolic flux for PHB production by regulating the sequences and intervals of the citrate synthase gene (gltA) and PHB synthesis gene (phbCAB) expression. Consequently, the strain RBS34, which has high gltA expression and a time lag of 3 h, achieved the highest PHB content of 16.6 wt%, which was approximately 3-fold that of F34 (expressed at 0 h). The results indicate that the optogenetic dual-switch system was verified as a practical and convenient tool for increasing PHB production. Full article

Compliance measures emphasized in the Dodd-Frank Bill 2010, Section 165 is a response to the 2008 financial crisis, that requires large banks to maintain a minimum capital ratio. The Federal Reserve Bank (Fed) regulates capital of Bank Holding Companies (BHC) through compliance Supervisory Capital Assessment Program (SCAP) 2009 and Comprehensive Capital Adequacy Review (CCAR) 2011 annual stress test of capital. The Fed imposed a minimum capital ratio of 8% that has derailed the risk management objective of capital adequacy, as bank managers are forced to take on more risk to meet the capital ratio. This study concerns senior manager practices that can be effective in meeting compliance requirements posed by the Fed for BHCs. Through a qualitative e-Delphi study, 10 banking finance experts were convened to build consensus on senior manager’s practices that can be effective in meeting compliance requirements. Data were collected from three electronic questionnaires submitted through Qualtrics. Data were analyzed using theoretical triangulation, coding, and thematic analysis. Four important considerations were identified that could bolster compliance measures effectiveness: (a) emphasis placed on understanding regulatory consultant compliance, (b) maintenance of effective and independent compliance align to organizational objectives, (c) clear definition of data source for compliance analytics. These considerations of compliance practices may help senior bank managers reduce risky behaviors and investments that cause significant bank losses. Full article

Heat shock protein 60 (HSP60) and survivin reside in both the cytosolic and mitochondrial compartments under physiological conditions. They can form HSP60-survivin complexes through protein–protein interactions. Their expression levels in cancer tissues are positively correlated and higher expression of either protein is associated with poor clinical prognosis. The subcellular location of HSP60-survivin complex in either the cytosol or mitochondria is cell type-dependent, while the biological significance of HSP60-survivin interaction remains elusive. Current knowledge indicates that the function of HSP60 partly rests on where HSP60-survivin interaction takes place. HSP60 has a pro-survival function when binding to survivin in the mitochondria through interacting with other factors such as CCAR2 and p53. In response to cell death signals, mitochondrial survivin functions through preventing procaspase activation. Degradation of cytosolic survivin leads to the loss of mitochondrial membrane potential and aberrant mitosis processes. On the other hand, HSP60 release from mitochondria to cytosol upon death stimuli might exert a pro-death function, either through stabilizing Bax, enhancing procaspase-3 activation, or increasing protein ubiquitination. Combining the knowledge of mitochondrial HSP60-survivin complex function, cytosolic survivin degradation effect, and pro-death function upon mitochondria release of HSP60, a hypothetical scenario for HSP60-survivin shuttling upon death stimuli is proposed. Full article

In wireless multi-hop networks, instead of using the traditional store-and-forward method, the relay nodes can exploit the network coding idea to encode and transmit the packets in the distributed coding-aware routing (DCAR) mechanisms, which can decrease the transmission number and achieve higher throughput. However, depending on the primary coding conditions of DCAR, the DCAR-type schemes may not only detect more coding opportunities, but also lead to an imbalanced distribution of the network load. Especially, they are not energy efficient in more complex scenarios, such as wireless ad-hoc networks. In this paper, to solve these shortcomings, we propose a constrained coding-aware routing (CCAR) mechanism with the following benefits: (1) by the constrained coding conditions, the proposed mechanism can detect good coding opportunities and assure a higher decoding probability; (2) we propose a tailored “routing + coding” discovery process, which is more lightweight and suitable for the CCAR scheme; and (3) by evaluating the length of the output queue, we can estimate the states of coding nodes to improve the efficient coding benefit. To those ends, we implement the CCAR scheme in different topologies with the ns-2 simulation tool. The simulation results show that a higher effective coding benefit ratio can be achieved by the constrained coding conditions and new coding benefit function. Moreover, the CCAR scheme has significant advantages regarding throughput, average end-to-end delay, and energy consumption. Full article