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To enhance the applied value of transglutaminase (TGase), various methods have been employed to improve its catalytic properties. However, most modifications have targeted the N-terminus, while the role of the C-terminus in determining TGase properties has been overlooked. In this study, we focused on enhancing the thermal stability of Streptomyces hygroscopicus TGase by engineering its C-terminal region. Modeling revealed that the C-terminal loop interacts with the N-terminal loop through hydrogen bonds between Trp331 and N-terminal residues (Asp19, Ala20, Tyr21). Removing the last C-terminal residue (Ser322) had no significant effect on TGase stability, but deleting additional residues (Trp331, Gly330, Gln299) led to inactivation. Substituting Trp331 with Ala reduced TGase's half-life at 50 °C and specific activity by 50% and 70%, respectively, highlighting the importance of C-terminal interactions in TGase stability. We also attempted to fuse three self-assembling amphipathic peptides (SAPs) (EAK16, KL15, ELK16) and a C-terminal sequence (IGCIILT) from Sulfolobus tokodaii RNase HI to TGase. The fusion of IGCIILT increased TGase's half-life by 1.5-fold without affecting specific activity, while the three SAPs had little effect on stability. Structural analysis showed that the fusion of IGCIILT raised TGase's melting temperature by 5.2 °C and altered its tertiary structure. Our results indicate that the C-terminus is important for modulating TGase properties, and fusing "stabilization tags" like IGCIILT at the C-terminus is a promising strategy to enhance thermal stability. [ABSTRACT FROM AUTHOR]

Aim: Respiratory sarcopenia (RS) has been newly defined in a position paper by four professional organizations in Japan, and it is necessary to examine its incidence and influencing factors using this new definition. So far, little work has been undertaken; we therefore conducted a longitudinal study to fill this gap. Methods: Our data were extracted from the China Health and Retirement Longitudinal Study. A total of 4301 older adults with complete data and without RS were chosen in 2011, of whom 3065 were followed up until 2015. The presence of low respiratory muscle strength plus low appendicular skeletal muscles mass was defined as RS based on t. A logistic regression model was used to identify the influencing factors for incident RS. Results: After an average of 4 years of follow‐up, the cumulative incidence of RS was 5.2%, and it was particularly high in participants aged >80 (20.9%). Logistic regression analysis showed that being unmarried/divorced/widowed (odds ratio [OR] = 1.85, 95% confidence interval [CI] = 1.28–2.66, P = 0.001), not having dyslipidemia (OR = 0.35, 95% CI = 0.19–0.65, P = 0.001), having digestive disease (OR = 1.56, 95% CI = 1.11–2.19, P = 0.010), asthma (OR = 2.77, 95% CI = 1.55–4.94, P = 0.001), edentulism (OR = 1.73, 95% CI = 1.24–2.42, P = 0.001), low handgrip strength (OR = 2.82, 95% CI = 1.99–3.99, P < 0.001), or low 5‐m gait speed (OR = 1.92, 95% CI = 1.23–3.01, P = 0.004) were associated with a greater likelihood of developing RS. After further adjustment for age and body mass index, asthma, edentulism, and low handgrip strength remained significant. Conclusions: The identification and management of older adults with the influencing factors described above could be important in preventing RS. Geriatr Gerontol Int 2024; 24: 1015–1021. [ABSTRACT FROM AUTHOR]

With the ever-increasing number of small satellites launched into space, on-board orbit determination is becoming more and more important. Precise satellite positions are needed for constellation maintenance, formation flying, communication optimization, collision avoidance and Earth observation. In addition, accurate time information is required for the functioning of the instruments on board. Low-cost off-the-shelf Global Navigation Satellite System (GNSS) receivers and antennas, adapted to the small size and weight of the satellite, allow precise on-board orbit determination and time synchronization for even the smallest satellites. We analysed more than one year of on-board navigation solutions (NAVSOL) from 8 Astrocast CubeSats, which are equipped with our multi-GNSS single-frequency payload. Based on the residuals from a dynamic orbit fitting, we found that the quality of the NAVSOL from the Astrocast satellites varies strongly both over time and between satellites, with an RMS ranging from a few meters to several tens of meters. In this study, we focus on three main effects that influence the quality of the NAVSOL from the Astrocast satellites: (1) The orbit-fit residuals show a positive radial offset in the range of about 6 m to 15 m, which is caused by ionospheric refraction. Our data show that GNSS signals at negative elevations are very strongly affected by the ionospheric refraction and thus account for the major part of the radial offset. (2) Discrepancies between the NAVSOL positions and velocities, and simulations with a GNSS signal generator show a once-per-revolution periodicity in the out-of-plane component, with amplitudes of 2 m and 5 cm/s in position and velocity, respectively. This effect is probably due to an inappropriate dynamic model used in the real-time navigation algorithm of the GNSS receiver. (3) Depending on the location of the GNSS antenna on board the satellite, the noise level varies by a multiple. This is assumed to be due to the antenna orientations, interference of the GNSS signals with electromagnetic waves coming from the satellite platform, signal attenuation during the transmission from the antenna to the receiver and differences in the soldering or tuning of the individual GNSS antennas. These findings help us refine hardware configurations and firmware settings in preparation for future Astrocast satellites or other nanosatellite missions. By eliminating or minimizing the mentioned effects, we expect to consistently achieve an accuracy on the level of a few meters for the real-time navigation solution of commercial off-the-shelf single-frequency GNSS receivers in space. [ABSTRACT FROM AUTHOR]

Matrix metalloproteinases (MMPs) are crucial for tissue remodeling and immune responses in insects, yet it remains unclear how MMPs affect the various immune processes against pathogenic infections and whether the responses vary among insects. In this study, we used the lepidopteran pest Ostrinia furnacalis larvae to address these questions by examining the changes of immune‐related gene expression and antimicrobial activity after the knockdown of MMP14 and bacterial infections. We identified MMP14 in O. furnacalis using the rapid amplification of complementary DNA ends (RACE), and found that it was conserved and belonged to the MMP1 subfamily. Our functional investigations revealed that MMP14 is an infection‐responsive gene, and its knockdown reduces phenoloxidase (PO) activity and Cecropin expression, while the expressions of Lysozyme, Attacin, Gloverin, and Moricin are enhanced after MMP14 knockdown. Further PO and lysozyme activity determinations showed consistent results with gene expression of these immune‐related genes. Finally, the knockdown of MMP14 decreased larvae survival to bacterial infections. Taken together, our data indicate that MMP14 selectively regulates the immune responses, and is required to defend against bacterial infections in O. furnacalis larvae. Conserved MMPs may serve as a potential target for pest control using a combination of double‐stranded RNA and bacterial infection. [ABSTRACT FROM AUTHOR]

Anautogenous mosquitoes must blood feed on a vertebrate host to produce eggs. Each gonadotrophic cycle is subdivided into a sugar‐feeding previtellogenic phase that produces primary follicles and a blood meal‐activated vitellogenic phase in which large numbers of eggs synchronously mature and are laid. Multiple endocrine factors including juvenile hormone (JH), insulin‐like peptides (ILPs), ovary ecdysteroidogenic hormone (OEH), and 20‐hydroxyecdysone (20E) coordinate each gonadotrophic cycle. Egg formation also requires nutrients from feeding that are stored in the fat body. Regulation of egg formation is best understood in Aedes aegypti but the role different endocrine factors play in regulating nutrient mobilization and storage remains unclear. In this study, we report that adult female Ae. aegypti maintained triacylglycerol (TAG) stores during the previtellogenic phase of the first gonadotrophic cycle while glycogen stores declined. In contrast, TAG and glycogen stores were rapidly mobilized during the vitellogenic phase and then replenishment. Several genes encoding enzymes with functions in TAG and glycogen metabolism were differentially expressed in the fat body, which suggested regulation was mediated in part at the transcriptional level. Gain of function assays indicated that stored nutrients were primarily mobilized by adipokinetic hormone (AKH) while juvenoids and OEH regulated replenishment. ILP3 further showed evidence of negatively regulating certain lipolytic enzymes. Loss of function assays indicated AKH depends on the AKH receptor (AKHR) for function. Altogether, our results indicate that the opposing activities of different hormones regulate nutrient stores during a gonadotrophic cycle in Ae. aegypti. [ABSTRACT FROM AUTHOR]

In this study, two different copper nickel ores produced in China and South Africa were taken as the research object, and the influence of grinding medium type on the flotation behavior of copper nickel ores was studied. The results show that the flotation recoveries of Cu and Ni of JC copper nickel ore from China after grinding with stainless steel medium are higher than those of cast iron medium, the grade of Cu is significantly improved, the floating speed of Ni is slower, and the floating amount of serpentine is greatly increased. However, the copper and nickel flotation recovery of NK copper nickel ore of South Africa after grinding with stainless steel medium is significantly lower than that of iron casting medium, and the mass draw of sulfide mineral and chromite is increased, while the mass draw of talc is significantly reduced. Galvanic effect in grinding process and hydroxyl complex produced by grinding of cast iron medium are important factors affecting flotation behavior of copper nickel sulfide minerals and gangue minerals. The difference in mineral composition of the two ores, to some extent, causes the difference in the influence of the above factors on the flotation behavior of the two ores. The gangue mineral of JC copper nickel ore is mainly serpentine. The Fe produced in the grinding process of cast iron medium has a living effect on serpentine, which makes the serpentine float up in a large amount in the flotation process and reduces the concentrate grade. The effect of Gavanic on the flotation behavior of JC copper nickel ore is significant. The proper oxidation of copper minerals during grinding with stainless steel medium can improve the copper flotation speed and recovery rate, but has a negative impact on the flotation speed of nickel minerals. The content of talc in NK copper nickel ore reaches 7%. Due to the strong hydrophobicity of talc and the adsorption and consumption capacity of the foaming agent and collector, a large proportion of the foaming agent and collector of NK copper nickel ore are consumed by talc when grinding with stainless steel medium, resulting in a significant reduction in the flotation amount of sulfide minerals, but the flotation speed of copper sulfide minerals is still improved to a certain extent by the effect of gavanic. The cover of iron hydroxy speicies produced by grinding of cast iron medium on the surface reduces the absorption consumption of talc for frother and collector to a certain extent, thereby increasing the mass draw of nickel sulfide and pyrrhotite in the ore. [ABSTRACT FROM AUTHOR]

• Topological valley metamaterial featuring reconfiguration and gradient is designed. • Low-frequency topological edge states can be achieved as low as 300 Hz. • Topological rainbow trapping of elastic waves in gradient structures is realized. • Application potential on energy localization and adjustable waveguide is explored. Elastic topological metamaterials are innovative fields of the fusion of physics and mechanics. Through novel microstructural designs, elastic topological metamaterials provide a pioneering approach to precisely manipulate elastic waves, maintaining robustness and efficiency in wave propagation even within complex environments. Recent advancements in reconfigurability and gradient features have significantly enriched the mechanical phenomena of wave manipulation, broadening the application potential of elastic topological metamaterials. In this study, we design the local resonant phononic crystal, employing a spiral support structure to ensure low-frequency characteristics and adjustable mass for flexible configuration. By utilizing the designed lattices with distinct topological phases, the topological valley edge states are constructed. The frequency and group velocity variation of the topological edge states under different stiffness and mass parameters are analyzed. Furthermore, we further constructed the mass and stiffness gradient metamaterial to analyze the transmission law of elastic waves in topological metamaterials. Additionally, the fluctuation features of the wave transmittance under disordered and impurity defects were discussed, confirming the robustness of waveguides within low-frequency topological metamaterials. Finally, we explored the potential applications of the designed metamaterials in energy localization and low-frequency reconfigurable waveguides. Numerical analysis showed that the topological gradient metamaterials can enhance the vibration energy at a specific interface, and low-frequency bend waveguide paths can be adjusted flexibly by configurable mass. In summary, this paper focuses on the low-frequency and gradient features of elastic topological metamaterials, aiming to unlock their application potential in vibrational energy harvesting, vibration suppression, and information transmission, which accelerate the practical implementation of topological metamaterials. [Display omitted] [ABSTRACT FROM AUTHOR]

• Topological edge states of various waves modes are realized in plate-like systems. • Ideal mode separation of in-plane and out-of-plane waves is achieved. • Topological whispering-gallery mode further enhances the wave energy localization. • Potential applications of mode separation for energy harvesting are explored. Topological metamaterials in condensed matter systems have shown significant potential for information and energy applications due to their novel wave propagation behaviors. Recently, there has been an increasing focus on studying topological metamaterials in classical wave systems. Elastic waves, as full-vector classical waves, possess more intricate mechanical characteristics compared to sound waves and electromagnetic waves. This complexity not only offers diverse practical application possibilities but also presents notable research challenges in the field of topological metamaterials. In this study, our main objective is to achieve the ideal mode separation of elastic waves, specifically separated into the in-plane and out-of-plane components, and explore its potential applications. Firstly, we design phononic crystals with dual Dirac cones. Through geometric perturbation, we successfully separate the valley Hall phases of in-plane and out-of-plane modes. By superimposing different topological phases, we achieve three types of topological edge states: in-plane waves, out-of-plane waves, and hybrid waves. Combining these different topological edge states enables us to effectively separate the elastic waves into in-plane and out-of-plane components. Furthermore, we investigate the potential application of mode separation in energy harvesting. We achieve the energy localization of different wave modes based on the topological whispering-gallery mode. Additionally, by utilizing piezoelectric materials, we realize the subregional energy harvesting of in-plane and out-of-plane modes. The mechanical properties resulting from mode separation and topological whispering-gallery mode hold great potential for signal filtering and energy storage, thereby opening up new possibilities for controlling and utilizing elastic waves in various engineering scenarios. [Display omitted] [ABSTRACT FROM AUTHOR]

Tooth fractures and cracks are common defects in gear transmission systems. Crack propagation paths of the spur gears are acquired using the fracture mechanics theory. Based on the simulated crack propagation path, the flexible body model of the cracked gear system is established in multibody dynamic software ADAMS. The vibration signals of cracked gear under different torques obtained from the simulation are verified by the experimental results. Some statistical indictors (root mean square and Kurtosis) are used to quantify the damage degree. In addition, the fault features of the gear system under crack and tooth fracture faults are analyzed by utilizing the instantaneous energy. The results indicate that the amplitude of the harmonics of the meshing frequency and the sideband frequencies increase gradually with the increase of torques and crack lengths. Especially, for the tooth fracture fault, its influence on Kurtosis value is particularly obvious. Meanwhile, according to the instantaneous energy, the tooth fracture fault will result in severe energy impacts and cause a sharp increase in the vibration amplitude. [ABSTRACT FROM AUTHOR]

Mosquitoes including Aedes aegypti are human disease vectors because females must blood feed to produce and lay eggs. Blood feeding triggers insulin-insulin growth factor signaling (IIS) which regulates several physiological processes required for egg development. A. aegypti encodes 8 insulin-like peptides (ILPs) and one insulin-like receptor (IR) plus ovary ecdysteroidogenic hormone (OEH) that also activates IIS through the OEH receptor (OEHR). In this study, we assessed the expression of A. aegypti ILPs and OEH during a gonadotrophic cycle and produced each that were functionally characterized to further understand their roles in regulating egg formation. All A. aegypti ILPs and OEH were expressed during a gonadotrophic cycle. Five ILPs (1, 3, 4, 7, 8) and OEH were specifically expressed in the head, while antibodies to ILP3 and OEH indicated each was released after blood feeding from ventricular axons that terminate on the anterior midgut. A subset of ILP family members and OEH stimulated nutrient storage in previtellogenic females before blood feeding, whereas most IIS-dependent processes after blood feeding were activated by one or more of the brain-specific ILPs and/or OEH. ILPs and OEH with different biological activities also exhibited differences in IIS as measured by phosphorylation of the IR, phosphoinositide 3-kinase/Akt kinase (AKT) and mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK). Altogether, our results provide the first results that compare the functional activities of all ILP family members and OEH produced by an insect. [Display omitted] • All ILPs and OEH are expressed during a gonadotrophic cycle. • Brain-produced ILPs, OEH stimulate nutrient storage during the previtellogenic phase. • Brain-produced ILPs, OEH and 20-hydroxyecdysone regulate vitellogenesis. • ILPs and OEH differentially signal in ovaries, pelts, and guts. [ABSTRACT FROM AUTHOR]

• Valley hall edge states and valley-locked waveguides are achieved in low-frequency elastic metamaterials. • Physical properties of valley-locked waveguide states and tunneling effects in local resonant metamaterials are analyzed. • Coupling transmission characteristics between valley-locked waveguides and tunneling effects are revealed. • Phonon applications, signal splitters, topological energy concentrators, and logical gates, are explored both numerically and experimentally. Topological valley metamaterial in classical wave systems has shown great potential for manipulating electromagnetic, acoustic, and elastic waves due to the defect-immune and lossless energy properties. The application prospects of topological valley material on signal processing, structural damage detection, and energy harvesting are worth exploring further. In this study, we combine the valley Hall effect and the tunneling effect of local resonant metamaterials to reveal some novel coupling transport phenomena in elastic systems. Some potential applications are explored experimentally and numerically. First, we implement a low-frequency (<1 kHz) valley-locked waveguide in heterostructures based on the topological valley edge state of the local resonant metamaterial. The robustness of the topological valley-locked waveguide under wide valley-locked layers, impurities, disorder, and bends is verified. Next, we introduce tunneling phenomena into the topological valley-locked waveguide, enabling the realization of an on-off controllable heterojunction by sandwiching crystals with different Dirac cones. The difference between the transmission characteristics of valley-locked waveguides under different tunneling layers (potential barrier and well) is revealed. Finally, we explore potential applications such as signal splitters, energy concentrators, and logical gates, both numerically and experimentally. Beyond the presented applications, this research has promising application prospects for vibration signal processing and high-performance energy harvesting. [Display omitted] [ABSTRACT FROM AUTHOR]

Background: Alcohol consumption is increasing all over the world, but whether it is an independent factor affecting the occurrence of nasopharyngeal carcinoma (NPC) is inconsistent in many studies. We aimed to explore the association between alcohol consumption and NPC risk by integrating existing evidence in a meta‐analysis. Methods: We searched for relevant articles published up to August 2018 in PubMed, Cochrane Library, Web of Science, and China National Knowledge infrastructure (CNKI). The Newcastle–Ottawa scale was used to assess the quality of the included studies. Odds ratios (ORs) or relative risks were pooled to estimate the associations between alcohol consumption and NPC risk. Results: The meta‐analysis of cohort studies showed no significant association between alcohol consumption and NPC, but pooled results from case–control studies indicated that ever drinking increased the probability of NPC versus nondrinking (OR = 1.10; 95% confidence interval [CI]: 1.01, 1.19). As compared with nondrinkers, high‐frequency drinking (≥7 times/wk) increased the NPC probability (OR = 1.29; 95% CI: 1.05, 1.53) and low‐frequency drinking (<7 times/wk) decreased the probability (OR = 0.77; 95% CI: 0.60, 0.94), as did shorter duration of drinking (<20 years) (OR = 0.64; 95% CI: 0.49, 0.79). On subgroup analyses, significant pooled results were observed for studies with high quality, with hospital‐based controls and with adjustment for confounding factors, smoking, age, and sex. Conclusions: The risk of NPC may increase with alcohol consumption. Ever drinking increased the risk versus nondrinking. Additionally, high‐frequency drinking increased the risk, but low‐frequency drinking decreased it to some extent. Further intensive studies based on well‐designed methods are needed to examine the association. [ABSTRACT FROM AUTHOR]

• An analytical-finite-element method for calculating mesh stiffness of spur gears is proposed. • A local rigid area technique is used to avoid the inappropriate local distortion in the contact position. • The effects of different gear foundation types on mesh stiffness of spur gears are analyzed. • The effects of different crack propagation paths on the mesh stiffness of spur gears are studied. Based on the finite element theory and the loaded tooth contact analysis, an analytical-finite-element model considering the complex foundation types and the crack propagation paths is proposed to calculate the mesh stiffness of spur gears. The complex gear foundation types (including web foundation and slots foundation) and the crack propagation paths (including tooth fracture and rim fracture) are considered in the proposed method, and the effects of various foundation types, crack propagation paths and crack lengths on the mesh stiffness are analyzed. In order to verify the proposed method, the simulated crack paths are confirmed by those derived from the experimental and the extended finite element methods, and the mesh stiffness obtained from the proposed method is validated by that of the potential energy method and the three-dimensional finite element method. Compared with the potential energy method, the proposed model can be used to calculate the mesh stiffness of spur gears with different gear foundation types and real crack propagation paths. Meanwhile, the proposed method has higher computational efficiency compared with the finite element method (e.g., the finite element method takes about 3.5 h for a mesh cycle and the proposed method costs 25 s). The results indicate that the web thickness has greater influence on the mesh stiffness of spur gears than the rim thickness. The results show that two crack types, namely the tooth fracture and rim fracture, have more obvious influence on the mesh stiffness of single-tooth contact zone relative to that of the double-tooth contact zone. [ABSTRACT FROM AUTHOR]

Highlights • A mesh stiffness analytical model of helical gears with spalling is established. • Mesh stiffness is compared with that using finite element (FE) method. • Contact stress and tooth root stress are compared using analytical and FE methods. • Mesh characteristics under different spalling parameters are analyzed. Abstract This paper investigates the effect of a gear tooth spalling in a helical gear. An analytical model was developed to study the effect of the damage to the time-varying mesh stiffness, contact stress and tooth root fillet stress. In order to validate the efficiency and the accuracy of the proposed method, a finite element method is presented for simulation, such to compare the mesh stiffness and stresses obtained from the analytical method under different spalling variables, including the spalling lengths, widths, axial positions (in the direction of face width) and tooth orientation positions (from dedendum to addendum). The results show that the proposed analytical method has higher computation efficiency than the finite element method, and the mesh stiffness obtained from two methods shows a good agreement. However, some errors exist between the time-varying mesh stiffness and stresses obtained by the two methods, but change laws of the tooth root stress and contact stress obtained from the two methods are similar. This is because the effects of flank-tip contact and spalling edge contact are considered in the finite element method, which makes the results more accurate than the results obtained by the proposed analytical method. [ABSTRACT FROM AUTHOR]

Highlights • A finite element (FE) model of a cracked rotating compressor blade (CRCB) is developed. • The CRCB model includes real crack paths. • Crack breathing mechanism is highlighted for centrifugal and aerodynamic forces. • Vibration responses of CRCB during run-up process are analyzed under different conditions. Abstract There exists a lot of research on the breathing-crack induced nonlinear vibration for beam-like structures. To the best of our knowledge, these studies mainly focus on the non-rotating uniform beam. Little research on the cracked compressor blade with varying-section and twisted shape has been performed considering the rotational effects (i.e., Coriolis force, stress stiffening, spin softening and angular acceleration) and comparatively accurate crack propagation paths (i.e., semi-elliptical crack). In this paper, typical fatigue cracks analyzed in referenced crack propagation path simulation and experimental tests are introduced into the ANSYS finite element (FE) model of a rotating compressor blade, which accounts for the influence of rotational effects. Then the effects of angular acceleration, amplitude of aerodynamic force and crack parameters (i.e., crack position, crack depth and crack height) on the dynamic characteristics of a cracked compressor blade during run-up process (RUP) are discussed. The results show that the crack-induced second- and third-order super-harmonics can be observed and become more evident with increasing crack severity (i.e. crack position closer to blade root surface or a larger crack depth/height) during RUP. Moreover, aerodynamic force plays a dominant role in affecting crack-breathing behavior at low speeds, while centrifugal force dominates the crack-breathing behavior at high speeds. [ABSTRACT FROM AUTHOR]

Abstract Based on the slice method, a new method is proposed for calculating the time-varying mesh stiffness (TVMS) of helical gears. The proposed method uses the idea of 'offset and superposition' to avoid the repetitive calculation of the TVMS of each sliced gear. Taking the TVMS obtained from the finite element (FE) method as a benchmark, the correction coefficient of the gear foundation stiffness is obtained by the optimization method. Four types of spatial crack are modeled, including addendum non-penetrating crack, addendum penetrating crack, end face non-penetrating crack and end face penetrating crack. The computational efficiency and accuracy are discussed under different crack parameters and crack types. Compared with the FE method and the traditional analytical method, the proposed method agrees well, and its efficiency is higher. For example, the proposed method costs 8 s to calculate the TVMS of helical gears with identical slice profile in one mesh period, while the traditional method and the FE method cost 2 min and 2.5 h, respectively. For the helical gears without identical slice profile, the proposed method is also applicable but the improvement of the calculation efficiency is not evident. The effects of extended tooth contact are ignored in the proposed analytical method, which leads to some errors between the TVMS of the cracked helical gears obtained from the proposed method and the FE method, but the change laws of the TVMS are in consistent. Highlights • A mesh stiffness model of helical gears with different crack types is established. • Mesh stiffness is compared with that from finite element (FE) method. • The proposed model is also revised based on FE method. • Mesh mesh stiffness under different crack parameters are analyzed. [ABSTRACT FROM AUTHOR]

Abstract Gear weight optimization is mainly through thin-web and hole in gear foundation. In this paper, an analytical-finite-element model for calculating time-varying mesh stiffness of spur gear pairs with complicated foundation (thin-web and holes) and crack is developed. The pinion and gear foundations are simulated as cylinders and modeled by three-dimensional finite element. The tooth pair is equivalent to a spring and mesh stiffness of a tooth pair is obtained by potential energy method. The spring is rigidly coupled with the pinion and gear foundations. Then, three type examples are presented to verify the model. The first type example is three spur gear pairs with solid foundation. The second type example is gear pairs with thin-web and web holes. And the third example is a gear pair with the cracked foundation. The analysis results show that the model proposed in this paper is applicable and efficient for spur gears with complicated foundation and crack. Finally, the time-varying mesh stiffness is also studied to reveal the effects of web widths, web hole radii and crack lengths. Highlights • An analytical-FE model for calculating time-varying mesh stiffness of spur gear pairs is developed. • Mesh stiffness is compared with that from finite element (FE) method. • The effects of cracked foundation are considered. • Mesh stiffness under different cases are analyzed. [ABSTRACT FROM AUTHOR]

The silkworm Bombyx mori , an economically important insect that is usually reared indoors, is susceptible to various pathogens, including bacteria, fungi, viruses, and microsporidia. As with other insects, the silkworm lacks an adaptive immune system and relies solely on innate immunity to defend itself against infection. Compared to other intensively studied insects, such as the fruit fly and tobacco hornworm, the principal immune pathways in the silkworm remain unclear. In this article, we review the literature concerning silkworm immune responses to bacteria and fungi and present our perspectives on future research into silkworm immunity. [ABSTRACT FROM AUTHOR]

Considering the real crack propagation paths using the fracture mechanics theory, a novel simulation dynamic model for the two-stage cracked gear drive of the wind turbine is established. The mesh characteristics (time-varying mesh stiffness, contact stress) are obtained with the finite element method. The mesh stiffness under the single-stage and multi-stage cracks is imported into the two-stage cracked gear drive dynamic model to solve the dynamics. The results of the simulation and experiment are performed to verify the proposed dynamic model. The dynamic characteristics and statistical indicators under different cracks are discussed. The results reveal that the crack has a significant influence on the mesh stiffness of the single-tooth contact zone. A rotating periodic impact is found on the time-domain response for the cracked gear drive. Under the single-stage crack, the components of rotating sideband frequencies also appear in the other-stage healthy gear drive. The gear acceleration amplitudes under the multi-cracks are larger than that under the single-stage crack. Therefore, the single-stage crack has an influence on the other-stage gear in the coupling system. This developed result can be applied well to vibration measurement and fault diagnosis. [ABSTRACT FROM AUTHOR]

Prophenoloxidase (proPO), immune deficiency (IMD), and Toll are the major signaling pathways leading to melanization and antimicrobial peptide production in insect hemolymph. Peptidoglycan recognition proteins (PGRPs) act as receptors and negative regulators in these pathways, and some PGRPs exhibit antimicrobial activity. Previously, we demonstrated that silkworm PGRP-S5 recognizes peptidoglycans (PGs) and triggers activation of the proPO pathway. It also acts as a bactericide, via its amidase activity (Chen et al., 2014). Here, we generated a C177S site-mutated silkworm PGRP-S5 protein that lacked amidase activity but retained its PG-binding capacity. Functional studies showed that the mutation caused loss of its receptor function for activation of the proPO pathway, suggesting that processing of PG by PGRP-S5 is necessary for formation of the pathway initiation complex. Further, we found that PGRP-S5 negatively regulates antimicrobial peptides generation in an amidase-dependent manner, likely through the IMD pathway. Thus, silkworm PGRP-S5 acts as a sensor, a modulator, and an effector in the silkworm humoral immune system. [ABSTRACT FROM AUTHOR]

Iron functions as a nutrient and a potential toxin in all organisms. It plays a key role in the interaction between microbes and their hosts as well. Microbial infection disrupts iron homeostasis in the host; meanwhile the host endeavors to keep the homeostasis through iron transport and storage. Transferrins and ferritins are the major iron-binding proteins that affect iron distribution in insects. In this study, we investigated a possible involvement of Bombyx mori ferritin 1 (BmFer1) heavy chain homolog in the defense against bacterial infection in the silkworm larvae. The BmFer1 mRNA abundance was up-regulated in hemocytes, but not in fat body, after Pseudomonas aeruginosa or Staphylococcus aureus infection. The infection resulted in elevated iron levels in the hemolymph. Injection of recombinant BmFer1 protein into hemocoel reduced the plasma iron level after infection, limited the bacterial growth in the hemolymph, and resulted in a lower mortality caused by infection. Our study indicated that B. mori ferritin-1 may restrict iron access of the invading bacteria to block their growth as a defense strategy. [ABSTRACT FROM AUTHOR]

• The spatial crack of gears with complex foundation is simulated. • The improved three-dimensional loaded tooth contact analysis method is established. • The finite-element and the multi-body dynamic models are established. • The effects of the complex foundation and spatial crack on dynamic response are analyzed. Considering both spatial crack fault and complex foundation structure, the dynamic finite element model and multi-body dynamic model are established simultaneously to analyze the dynamic characteristics of gear-rotor systems. Firstly, the extended finite element method is used to simulate the three-dimensional crack propagation paths of spur gears under partial load. Then, based on the proposed three-dimensional loaded tooth contact analysis (3D-LTCA) method, the mesh stiffness of spur gears with the spatial crack and complex foundation is calculated and the results are verified by the finite element method. Finally, the dynamic finite element model and multi-body dynamic model of the gear-rotor system are established. The dynamic responses under different crack levels are analyzed. The advantages and disadvantages of these two dynamic models are evaluated. According to the above analysis, it is indicated that the 3D-LTCA can accurately consider the influence of complex foundation and spatial crack on mesh stiffness. The finite element model and multi-body dynamic model can effectively analyze the influence of crack fault and foundation structure on dynamic responses. [ABSTRACT FROM AUTHOR]

Highlights: [•] PGRP-S5 functions as a receptor to recognize bacteria and induces bacteria agglutination. [•] PGRP-S5 is an amidase and is an antibacterial protein. [•] PGRP-S5 is also involved in prophenoloxidase pathway in silkworm. [ABSTRACT FROM AUTHOR]

Streptomyces transglutaminase (TGase) is an important industrial enzyme that catalyzes cross-linking of proteins. It is secreted as a zymogene and then is activated by proteases under physiological conditions. Although the activation process of TGase has been well investigated, the physiological function of TGase in Streptomyces has not been revealed. In this study, physiological function of TGase from Streptomyces hygroscopicus was found to be involved in differentiation by construction of a TGase gene interruption mutation strain (Δtg). The mutant Δtg showed an absence of differentiation compared with the parent strain. Furthermore, the production of TGase was found to be increased with the extending growth arrest phase of mycelium in submerged cultures. Thus, to enhance yield of TGase, the mycelium differentiation of Streptomyces was regulated via low temperature stress in a 3-L stirred-tank fermenter. The production of TGase increased by 39 % through extending the growth arrest phase for 4 h. This study found that TGase is involved in Streptomyces differentiation and proposed an approach to improve TGase production by regulation of mycelium differentiation in submerged cultures. [ABSTRACT FROM AUTHOR]

Highlights: [•] The N-terminal α-helix12–30 is essential for the pro-TGase folding and secretion by disruption of the hydrogen bonds. [•] The α-helix37–42 has negative influence in TGase activity. [•] The accumulation of pro-TGase in supernatant secreted by the mutant without loop43–52 increased by 70%. [ABSTRACT FROM AUTHOR]

Streptomyces transglutaminase (TGase) has been widely used in food, pharmaceutical and textile industries. Streptomyces TGase is naturally synthesized as zymogen (pro-TGase), which is then processed to produce active enzyme by removing its N-terminal pro-peptide. Although the pro-peptide is essential for TGase folding and secretion, few studies have been reported on improving the properties of TGase by pro-peptide engineering. In this study, we developed a new approach to improve the properties of TGase based on pro-peptide engineering. When the α-helix in pro-peptide was substituted with three glycines and three alanines respectively, the mutants exhibited higher specific activity and the efficiency of pro-peptide cleavage was enhanced. To further improve the properties of TGase, relevant mutations were constructed by introducing linker peptides in the C-terminus of the pro-peptide. Mutants with GS (GGGGS) and PT (PTPPTTPT) linker peptide exhibited 1.28 fold and 1.5 fold higher specific activity than the wild-type enzyme, respectively. This new method could be used to improve the properties of TGase by pro-peptide modification, which is a promising technology for creating unique TGase with various beneficial properties. [ABSTRACT FROM AUTHOR]

Abstract: Transglutaminase (TGase) is an important industrial enzyme that catalyzes the cross-linking of proteins. In this study, the N-terminal residues were deleted and substituted to improve the activity and thermostability of Streptomyces hygroscopicus TGase. Seven N-terminal residues of TGase were chosen to be deleted individually. The mutated TGase missing the first four residues showed an increase in specific activity of 32.92%. The fifth residue (E5) in the N-terminus was then selected for substitution with the 19 other amino acids. The mutant replacing the fifth residue with an aspartic acid exhibited a 1.85-fold higher specific activity and a 2.7-fold longer half-life at 50°C when compared with the wild-type enzyme. The melting temperature of the mutated TGase increased from 68.9 to 79.1°C by circular dichroism spectroscopy analysis. This study showed that substitution combined with deletion of the N-terminal amino acids could enhance the activity and thermostability of TGase. [Copyright &y& Elsevier]

The silkworm, Bombyx mori , is utilized as a research model in many aspects of biological studies, including genetics, development and immunology. Previous biochemical and genomic studies have elucidated the silkworm immunity in response to infections elicited by bacteria, fungi, microsporidia, and viruses. The intestine serves as the front line in the battle between insects and ingested harmful microorganisms. In this study, we performed RNA sequencing (RNA-seq) of the larval silkworm midgut after oral infection with the Gram-positive bacterium Bacillus bombysepticus and the Gram-negative bacterium Yersinia pseudotuberculosis. This enables us to get a comprehensive understanding of the midgut responses to bacterial infection. We found that B. bombysepticus induced much stronger immune responses than Y. pseudotuberculosis did. Bacterial infection resulted in more energy consumption including carbohydrates and fatty acids. The midgut immune system was characterized by the generation of reactive oxygen species and antimicrobial peptides. The former played a critical role in eliminating invading bacteria during early stage, while the latter executed during late stage. Our results provide an integrated insight into the midgut systematic responses to bacterial infection. • Comprehensive analysis of the silkworm midgut responses to bacterial infection by transcriptome sequencing. • Bacterial infection resulted in more consumption of carbohydrates and fatty acids. • The midgut immune system was characterized by the generation of reactive oxygen species and antimicrobial peptides. • Reactive oxygen species played a critical role in eliminating invading bacteria during early stage, while antimicrobial peptides executed during late stage. [ABSTRACT FROM AUTHOR]

• Realistic spalling geometries are obtained from fatigue experiments. • The mesh stiffness and contact stress are verified by the finite element method. • Dynamic behaviors of the single and multiple teeth spallings are discussed. • Simulated fault features are verified by that obtained from the experiment. Considering the realistic spalling morphology obtained from the fatigue experiment, a novel dynamic model for spalled gear pairs is established in this paper. Loaded tooth contact analysis method is utilized to evaluate the meshing characteristics of spalled gear pairs. In order to verify the proposed method, the mesh stiffness and contact stress obtained from the proposed method are compared with those obtained from the finite element method and the method in published literature. The mesh stiffness and the non-loaded static transmission error are imported into the geared rotor dynamic model to acquire the dynamic responses. The spectrum characteristics and statistical indicators under different spalling patterns are acquired by the proposed model. A comparison between simulation and experiment is performed to verify the proposed dynamic model. The results show that the simulated fault features agree well with that obtained from the experiment, which indicates that the proposed model is a promising tool for the fault mechanism study of gears with realistic spalling patterns. [ABSTRACT FROM AUTHOR]

Augmented reality (AR) near-eye displays seamlessly integrate virtual information with real world, in which the optical waveguide is the key component functioned as a coupler. Due to strong chromatic aberration, independent waveguides are always indispensable to separate the three primary colors that inevitably brings larger and thicker appearance. To address this, this paper proposes a new chromatic-aberration-free single-layer waveguide for AR displays by integrating a double-layer grating metasurface (MS) and the covered cylindrical MSs. The double-layer grating MS breaks through the limitations on a narrow wavelength band, enabling high diffraction efficiency for incident light deflection across the entire visible spectrum. Further, the cylindrical MSs provide accurate control over incident angles, not only overcoming the challenge of total reflection but also effectively eliminating chromatic aberration. Design results show that the proposed structure achieves an impressive diffraction efficiency of over 80 % for blue and green light and over 90 % for red light with an outstanding diffraction angular difference lower than 2.5 deg. Real-time ray tracing simulation demonstrates the capability of the designed AR engine to achieve high-resolution full-color imaging. The compound MSs enable precise light and color control for a single-layer waveguide coupler with exceptional diffraction efficiency and minimal chromatic aberration, which show great potential for cutting-edge AR applications. [ABSTRACT FROM AUTHOR]

Increasing evidence has shown that gut microbiota (GM) was involved in the pathophysiology of musculoskeletal disorders through multiple pathways such as protein anabolism, chronic inflammation and immunity, and imbalanced metabolism. We performed a systematic review and meta-analysis of human studies to evaluate GM diversity differences between individuals with and without sarcopenia, and explore bacteria with potential to become biomarkers. PubMed, Embase and Cochrane library were systematically searched from inception to February 16, 2024. Studies were included if they (1) sampled adults with sarcopenia, and (2) performed GM analysis and reported α-diversity, β-diversity or relative abundance. The methodological quality of included studies and the certainty of evidence were assessed through the Joanna Briggs Institute critical appraisal checklist for analytical cross-sectional studies and the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) Working Group system, respectively. Weighted standardized mean differences (SMDs) and corresponding 95% confidence intervals (CIs) were estimated for α-diversity indices using a fixed-effects and a random-effects model. Beta diversity and the relative abundance of GM were summarized qualitatively. A total of 19 studies involving 6,565 participants were included in this study. Compared with controls, significantly moderate decrease in microbial richness in participants with sarcopenia were found (Chao1: SMD = -0.44; 95%CI, -0.64 to -0.23, I2 = 57.23%, 13 studies; observed species: SMD = -0.68; 95%CI, -1.00 to -0.37, I2 = 66.07%, 5 studies; ACE index: SMD = -0.30; 95%CI, -0.56 to -0.04, I2 = 8.12%, 4 studies), with very low certainty of evidence. Differences in β-diversity were consistently observed in 84.6% of studies and 97.3% of participants. The detailed analysis of the gut microbial differential abundance identified a loss of Prevotellaceae, Prevotella, and Megamonas in sarcopenia compared with non-sarcopenia. In conclusion, sarcopenia was found to be associated with reduced richness of GM, and supplementing intestinal bacteria described above may contribute to preventing and treating this muscle disease. The research protocol was registered and approved in PROSPERO (CRD42023412849). [ABSTRACT FROM AUTHOR]

Insects rely on their innate immune system to eliminate pathogenic microbes. As a system component, cytokines transmit intercellular signals to control immune responses. Growth‐blocking peptide (GBP) is a member of the stress‐responsive peptide family of cytokines found in several orders of insects, including Drosophila. However, the physiological role of GBP in defence against pathogens is not thoroughly understood. In this study, we explored the functions of GBP in a lepidopteran pest, Ostrinia furnacalis. Injection of recombinant O. furnacalis GBP (OfGBP) precursor (proGBP) and chemically synthesised GBP significantly induced the transcription of antimicrobial peptides (AMPs) and other immunity‐related genes including immune deficiency (IMD) and Dorsal. The level of OfGBP mRNA was upregulated after bacterial infection. Knockdown of OfGBP expression led to a decrease in IMD, Relish, MyD88 and Dorsal mRNA levels. OfGBP induced phenoloxidase activity and affected hemocyte behaviours in O. furnacalis larvae. In summary, GBP is a potent cytokine, effectively regulating AMP synthesis, melanization response and cellular immunity to eliminate invading pathogens. [ABSTRACT FROM AUTHOR]

Antimicrobial peptides (AMPs), as immune effectors synthesized by a variety of organisms, not only constitute a robust defense mechanism against a broad spectrum of pathogens in the host but also show promising applications as effective antimicrobial agents. Notably, insects are significant reservoirs of natural AMPs. However, the complex array of variations in types, quantities, antimicrobial activities, and production pathways of AMPs, as well as evolution of AMPs across insect species, presents a significant challenge for immunity system understanding and AMP applications. This review covers insect AMP discoveries, classification, common properties, and mechanisms of action. Additionally, the types, quantities, and activities of immune-related AMPs in each model insect are also summarized. We conducted the first comprehensive investigation into the diversity, distribution, and evolution of 20 types of AMPs in model insects, employing phylogenetic analysis to describe their evolutionary relationships and shed light on conserved and distinctive AMP families. Furthermore, we summarize the regulatory pathways of AMP production through classical signaling pathways and additional pathways associated with Nitric Oxide, insulin-like signaling, and hormones. This review advances our understanding of AMPs as guardians in insect immunity systems and unlocks a gateway to insect AMP resources, facilitating the use of AMPs to address food safety concerns. [ABSTRACT FROM AUTHOR]

The International GNSS Service analysis centers provide orbit products of GPS satellites with weekly, daily, and sub-daily latency. The most frequent ultra-rapid products, which include 24 h of orbits derived from observations and 24 h of orbit predictions, are vital for real-time applications. However, the predicted part of the ultra-rapid orbits is less accurate than the estimated part and has deviations of several decimeters with respect to the final products. In this study, we investigate the potential of applying machine-learning (ML) and deep-learning (DL) algorithms to further enhance physics-based orbit predictions. We employed multiple ML/DL algorithms and comprehensively compared the performances of different models. Since the prediction errors of the physics-based propagators accumulate with time and have sequential characteristics, specific sequential modeling algorithms, such as Long Short-Term Memory (LSTM), show superiority. Our approach shows promising results with average improvements of 47% in 3D RMS within the 24-h prediction interval of the ultra-rapid products. In the end, we applied the orbit predictions improved by LSTM to kinematic precise point positioning and demonstrated the benefits of LSTM-improved orbit predictions for positioning applications. The accuracy of the station coordinates estimated based on these products is improved by 16% on average compared to those using ultra-rapid orbit predictions. [ABSTRACT FROM AUTHOR]

An efficient Cu(ii)-catalyzed, C–H alkylation of BODIPY with a variety of alkyl diacyl peroxides has been developed for the first time, providing a late-stage and straightforward method for controllable synthesis of monoalkylated and dialkylated BODIPYs via a radical process that otherwise is difficult to obtain by literature methods. This chemo- and site-selective transformation will allow for the introduction of a variety of functionalities on the BODIPY core for highly versatile tethering to receptors and to other molecules of interest. [ABSTRACT FROM AUTHOR]

• Analysis of mechanics, shrinkage, and durability of recycled mixture. • Evaluation of crack resistance by orthogonal analysis. • Quality inspection of regenerated road construction. In order to solve the problem of resource utilization of construction waste (C&W) recycled aggregate (RA) in rural road grassroots, natural aggregate (NA) was replaced by RA with 0%, 20%, 40%, 60%, 80% and 100% in the test. The unconfined compressive strength, splitting strength, compressive resilience modulus, dry shrinkage test, and frost resistance test were used to test the road performance of the recycled mixture. In order to improve the strength and crack resistance of cement stabilized regenerated mixture, three different admixtures (polypropylene fiber, expansion agent, and curing agent) were considered based on the orthogonal test to improve the crack resistance of the regenerated mixture, and their influence weights were analyzed. Relying on the Gaobeidian rural road network reconstruction project, the construction waste recycling test road was laid, and the construction quality of compaction, bending, and flatness was tested. The results show that the strength of cement-stabilized recycled mixture peaks when RA content is 20%. When RA content is 0% to 100%, the compressive strength decreases by 22.6%, compressive resilience modulus decreases by 18.7%, and tensile strength decreases by 33.2%. Adding 0.8‰ polypropylene fiber, 0.4% expansion agent, and 1.5% curing agent increased 21.2% 7d unconfined compressive strength, 7.8% in 7d splitting strength, and 43.2% in 14d drying shrinkage coefficient. The construction test results show that adding fiber and low-content construction waste increases the base load capacity, increases the compressive strength by 34.5%, reduces the base deflection by 10.5%, and has good road performance. Finally, considering the test results comprehensively, when the RA content is below 20%, and the polypropylene fiber content is between 0.6‰ and 0.8‰, it can meet the basic construction requirements of secondary and sub-secondary rural regeneration roads in China. [ABSTRACT FROM AUTHOR]

Background The present study aimed to identify individuals with different personalities using latent class analysis and further distinguish those with a high risk of diabetes among different clusters. Methods Data were utilized from a large-scale, cross-sectional epidemiological survey conducted in 2018 across 23 provinces in China, employing a multi-stage, stratified sampling technique. Latent class cluster analysis was performed to identify distinct personality clusters based on a series of variables concerning life attitudes. Logistic regression was used to calculate adjusted odds ratios (AORs) after controlling for potential confounding variables, including age, gender, body mass index, smoking status, alcohol consumption, hypertension, and physical activity levels, to determine the association between these groups and diabetes. Results Four distinct personality clusters were identified, namely the energy-poor (2.0%), self-domination (61.3%), optimistic (21.3%), and irritable (15.4%) groups. The prevalence of diabetes in these groups was 14.6%, 9.7%, 9.3%, and 11.6%, respectively. After adjusting for potential confounders, the "energy-poor group" exhibited more odds of having diabetes as compared to the "optimistic group" (AOR 1.683, 95%CI: 1.052–2.693; P =0.030). Conclusion This study identified an energy-poor group of individuals with a high risk of diabetes. Targeted interventions should consider the emotional and personality characteristics of the elderly. [ABSTRACT FROM AUTHOR]

The prophenoloxidase (PPO) activating system in insects plays an important role in defense against microbial invasion. In this paper, we identified a PPO activating protease (designated Of PAP) containing a 1203 bp open reading frame encoding a 400-residue protein composed of two clip domains and a C-terminal serine protease domain from Ostrinia furnacalis . SignalP analysis revealed a putative signal peptide of 18 residues. The mature Of PAP was predicted to be 382 residues long with a calculated M r of 44.8 kDa and pI of 6.66. Multiple sequence alignment and phylogenetic analysis indicated that Of PAP was orthologous to the PAPs in the other lepidopterans. A large increase of the transcript levels was observed in hemocytes at 4 h post injection (hpi) of killed Bacillus subtilis , whereas its level in integument increased continuously from 4 to 12 hpi in the challenged larvae and began to decline at 24 hpi. After OfPAP expression had been silenced, the median lethal time (LT 50 ) of Escherichia coli -infected larvae (1.0 day) became significantly lower than that of E. coli- infected wild-type (3.0 days, p  < 0.01). A 3.5-fold increase in E. coli colony forming units occurred in larval hemolymph of the OfPAP knockdown larvae, as compared with that of the control larvae not injected with dsRNA. There were notable decreases in PO and IEARase activities in hemolymph of the OfPAP knockdown larvae. In summary, we have demonstrated that Of PAP is a component of the PPO activation system, likely by functioning as a PPO activating protease in O. furnacalis larvae. [ABSTRACT FROM AUTHOR]

Fusarium graminearum is an economically devastating pathogen that causes cereal worldwide. The plant disease cycle involves sexual reproduction, with the perithecium playing a crucial role in overwintering and the discharge of ascospores. Although fatty acid biosynthesis and metabolism are linked to perithecium formation and ascospore discharge, the regulation of these processes remains largely unknown. In this study, we identified and characterized FgBZIP16, as a basic leucine zipper (b-ZIP) transcription factor, in F. graminearum. Targeted gene deletion revealed that FgBzip16 is important for vegetative growth, asexual/sexual development, and plant infection. Cytological observations revealed that FgBzip16 was localized in the nucleus during the hyphal and conidial stages. FgBzip16 is essential for ascospore discharge, with transcriptomics and molecular biology showing it binds to the promoter of its target genes FGSG_05321 and FGSG_03244, which regulate ascospore discharge by encoding fatty acid synthase subunit alpha-reductase and enoyl hydratase, respectively. Altogether, these results constitute the first report of the specific functions associated with b-ZIP transcription factor FgBzip16, linking its regulatory roles to fungal development, fatty acid accumulation, and metabolism, host penetration, and pathogenicity of F. graminearum. [ABSTRACT FROM AUTHOR]

High-density polyethylene (HDPE) is one of the most commonly used materials for manufacturing pipelines. In this paper, the deformation behavior of HDPE materials under uniaxial tensile stress was investigated by employing uniaxial tensile tests and macroscale/mesoscale morphology analysis. The experimental results indicated that the stress–strain relationship of HDPE is nonlinear, and the ductile fracture characteristics of necking and local failure appear in the sample after the engineering strain reaches 35%. Therefore, for the first time, a hyperelastoplastic constitutive model that describes the elasticity by the Marlow model and combined the isotropic plasticity-ductility damage correction is established, and a corresponding numerical approach is proposed. The simulation scheme was implemented in finite-element software, and the mechanical responses of HDPE under uniaxial tensile and bending loads were predicted. Obtained calculations were relatively consistent with experimental observations. Hence, the proposed model and approach have a good simulation effect on the mechanical properties of HDPE and can be employed for the process prediction of such materials. This study is beneficial to the in-depth understanding of the hyperelastoplasticity and failure mechanism of HDPE and provides ideas for the deformation and failure study of other polymer materials. [ABSTRACT FROM AUTHOR]

Compared to other insects, the pea aphid Acyrthosiphon pisum has a reduced immune system with an absence of genes coding for a lot of immunity‐related molecules. Notably, nitric oxide synthase (NOS), which catalyses the synthesis of nitric oxide (NO), is present in the pea aphid. However, the role of NO in the immune system of pea aphid remains unclear. In this study, we explored the role of NO in the defence of the pea aphid against bacterial infections and found that the NOS gene of the pea aphid responded to an immune challenge, with the expression of ApNOS observably upregulated after bacterial infections. Knockdown of ApNOS using RNA interference or inhibition of NOS activity increased the number of live bacterial cells in aphids and the mortality of aphids after bacterial infection. Conversely, the increase in NO level in aphids using NO donor inhibited the bacterial growth, increased the survival of bacteria‐infected aphids, and upregulated immune genes, such as Toll pathway and phagocytosis related genes. Thus, NO promotes immune responses and plays an important role in the immune system of pea aphid. [ABSTRACT FROM AUTHOR]

• A flexible gear dynamic system is developed to acquire the systematic elastic deformation. • A hybrid finite element-analytical contact algorithm is proposed to evaluate the non-ideal meshing states. • The simulated damage topography and dynamic characteristics are verified by the experimental results. • Coupling mechanisms between systematic elastic deformation and gear surface damage are revealed. Understanding the coupling mechanism between systematic elastic deformation and gear tooth surface damage is particularly helpful for us to explore the life-cycle surface damage evolution process. A deformable body dynamic model of gear transmission systems is developed to acquire the systematic elastic deformation. Then the equivalent meshing deviation parameters, which are used to quantify the systematic deformation, are imported into a hybrid finite element-analytical contact model to acquire the load distribution under non-ideal meshing conditions. Considering the concurrent effects of surface wear and pitting, a generalized surface damage model is developed based on the transient elastohydrodynamic lubrication theory. An interactive calculation scheme is built to realize the damage simulation over the life-cycle evolution process. Distinguishing from the conventional models, the proposed multi-physics model bridges the macroscopic systematic deformation and microscopic behaviours (local contact state and damage initiation mechanism). A two-staged gear test rig is utilized to verify the proposed model. Based on the proposed model, the coupling mechanism amongst the tribo-dynamic behaviours, systematic elastic deformation and life-cycle fault characteristics are analysed. It is revealed that the bending-induced asymmetric load distribution will lead to severe pitting at one edge of the gear surface; The life-cycle dynamic performance can be significantly improved by optimizing the supporting configuration. This work can provide the theoretical basis for the tooth fault prognosis, physics-based condition monitoring and configuration design. [Display omitted] [ABSTRACT FROM AUTHOR]

• A fast dynamic load distribution algorithm is proposed to obtain the dynamic load. • The iterative topography updating is involved in the dynamic pitting evolution. • The pitting prediction model is verified by experimental results. • The probability distribution of pitting is investigated from a physics-based perspective. • The tribo-dynamic behaviors of pitted gears during the life-cycle evolution are evaluated. Considering the coupling effects of the tribology and dynamics, a dynamic pitting evolution model of planetary gear sets is developed. A fast dynamic load distribution algorithm is proposed to obtain the dynamic contact load considering complex pitting topography. Then the mixed elastohydrodynamic lubrication theory is adopted to acquire the tribological parameters. Combing the dynamic load and Zaretsky's fatigue criterion, a contact fatigue model is developed to predict the pitting topography during the degradation process. An iterative algorithm framework is developed to realize the topographical updating in the dynamic pitting prediction. The effectiveness of the proposed model is demonstrated using two experimental examples. The probability distribution of the pitting location is investigated using the proposed model. It is revealed that the gamma distribution is more consistent with the pitting distribution along the involute direction than the normal distribution. Owing to the "competition mechanism" of the pitting and surface wear, the pitting center approaches the pitch point with the increase of the surface roughness. The proposed model is capable of evaluating tribo-dynamic behaviors of planetary gear sets during the life-cycle degradation process of pitting failure. Moreover, it can provide theoretical guidance for the pitting fault mechanism and model-based fault diagnosis. [Display omitted] [ABSTRACT FROM AUTHOR]

• A mediator algorithm between simulation and experiment is proposed to identify the error excitation. • The proposed identification algorithm provides an indirect approach to estimate the error excitation of gears. • The pre-decomposition technique is proposed to accelerate the solution of the simulation dynamic model. • The proposed identification algorithm is robust to noise, damping and phase differences. • The performance of the proposed identification algorithm is verified by both simulation and experiment. There are three primary sources of internal excitation in gear systems: time-varying mesh stiffness, meshing damping and tooth error. Compared with the first two excitations, it is more difficult to evaluate or measure the error excitation. The error excitation is usually assumed empirically or even neglected in the majority of dynamic models. To address this issue, we desired to propose a mediator algorithm between the simulation and the experiment to identify the error excitation of gear systems. Based on the second-order cyclostationarity of gear signals, a signal processing procedure is proposed to acquire the mediator signal with a high signal-to-noise ratio. The mediator signal is served as the "media" between the simulation and experiment. The error parameter is updated repeatedly in the iterative optimization until the optimal matching is found between the simulation and the experiment. Simultaneously, the pre-decomposition technique is proposed to accelerate the solution of the simulation dynamic model. The performance of the proposed identification algorithm is verified both numerically and experimentally. Moreover, noise immunity analysis shows that the proposed identification algorithm is robust to noise, damping and phase differences between the experiment and simulation. The proposed identification algorithm provides an indirect approach to estimating the error excitation when the direct measurement is unavailable. [ABSTRACT FROM AUTHOR]

Based on the thin slice assumption, a revised time-varying mesh stiffness (TVMS) model of spur gear pairs with tooth modifications is developed. The spur gear is divided into many individual slices along tooth width, and considering the revised fillet-foundation stiffness, the nonlinear contact stiffness, the extended tooth contact and the tooth profile errors, the stiffness of each slice gear pair is figured out. According to the relationship between the deformation and the total stiffness in mesh period, the TVMS of spur gear pairs can be worked out. Meanwhile, relative to the finite element (FE) method, the errors of the proposed method under different modification quantities are discussed. The proposed method is more accurate than those previous methods but there are still some errors. Taking the FE model as a benchmark, the TVMS is further revised based on a simple model updating technique. Based on the revised model, the effects of the tooth width and torque on mesh stiffness are also studied. The result shows that based on the proposed method, the TVMS under any given modification quantities in a suitable range can be calculated accurately. [ABSTRACT FROM AUTHOR]

• An in-situ transfer path analysis method is proposed to avoid physical decoupling ;. • A virtual decoupling method is applied to estimate the decoupled frequency response function;. • The effectiveness of the proposed method is verified both numerically and experimentally ;. • The proposed method is capable of tracing the fault location by determining the dominant transfer path;. • A physically-interpretable signal decomposition method is proposed to enhance the fault feature. A transfer path analysis method based on the in-situ measurement is proposed for the fault tracing of parallel axis gear systems. A virtual decoupling technique is used to achieve the in-situ measurement of the decoupled frequency response function (FRF) between bearing positions and measuring points on housing, avoiding the tedious test procedure and non-representative assembly conditions caused by the physical decoupling. Based on the decoupled FRF and the responses of the gearbox housing, the bearing force is identified using the Tikhonov regularization theory. Then the frequency-dependent path contribution, which will be used to perform the transfer path analysis, is obtained by multiplying the decoupled FRF and the bearing force. Finally, the fault-specific path rank order is determined using the path contribution within the resonant frequency band. This band is located by the spectral kurtosis algorithm. Based on the proposed in-situ path analysis, fault tracing is conducted by determining the dominant transfer path. The effectiveness of the proposed path analysis method is verified both numerically and experimentally. A two-stage parallel axis gear test rig with localized defects is utilized to demonstrate the efficacy of the proposed fault tracing strategy. Moreover, based on the path analysis, a physically-interpretable signal decomposition method is proposed to enhance the fault feature. Through this decomposition method, the fault indicator of the weakest fault type (chipped tooth) can be magnified by 204%. The proposed transfer path analysis method provides a feasible strategy for fault tracing, feature enhancement and incipient fault diagnosis of parallel axis gear systems. [Display omitted] [ABSTRACT FROM AUTHOR]

Myeloid differentiation factor 88 (MyD88) is a pivotal adapter protein involved in activating nuclear factor NF-κB of the Toll pathway in insect innate immunity. MyD88 has been extensively studied in vertebrates and Drosophila. However, the information ascribed to MyD88 in Lepidoptera is scarce. In the present study, an Ostrinia furnacalis MyD88 (OfMyD88) cDNA was cloned and functionally characterized (GenBank accession no. MN906311). The complete cDNA sequence of OfMyD88 is 804 bp, and contains a 630 bp open reading frame encoding 209 amino acid residues. OfMyD8 8 has the death domain (DD), an intermediate domain, and the Toll/interleukin 1 receptor (TIR) domain. OfMyD88 was widely expressed in immune-related tissues such as hemocytes, fat body, midgut, and integument, with the highest expression level in hemocytes, and the lowest expression level in integument. To clarify the immune function of MyD88, O. furnacalis larvae were challenged with Bacillus thuringiensis (Bt) through feeding. Bt oral infection had significantly up-regulated the expression of OfMyD88 and immune genes, including PPO 2 (prophenoloxidase 2), Attacin , Gloverin , Cecropin , Moricin , GRP 3 (β-1, 3-Glucan recognition protein 3), and Lysozyme , and increased the activities of PO and lysozyme in hemolymph of O. furnacalis larvae. Knockdown of OfMyD8 8 by RNA interference suppressed the expression levels of immune related genes, but not PPO 2 in the larvae orally infected with Bt, suggesting that OfMyD88 is involved in defending against Bt invasion through the Toll signaling pathway, but does not affect the PPO expression in O. furnacalis larvae. [Display omitted] • We cloned and characterized a MyD88 gene in Ostrinia furnacalis (Guenée). • Bacillus thuringiensis oral infection had significantly up-regulated the expression of OfMyD88 and immune genes, and increased the activities of PO and lysozyme in hemolymph of O. furnacalis larvae. • OfMyD88 is involved in defending against B. thuringiensis invasion through the Toll signaling pathway in O. furnacalis. [ABSTRACT FROM AUTHOR]

A 25,27- bis( l-phenylalaninemethylester- N-carbonylmethoxy)-26,28-dihydroxy- para- tert-butylcalix[4]arene-bonded silica gel stationary phase was synthesized, structurally characterized and used for LC. Its separation mechanism was studied and compared with octadecyl-bonded stationary phase, as well as our previously prepared para-tert-butylcalix[4]arene-1,2-crown-4 stationary phase. Meanwhile, the chromatographic behaviors were investigated by using polycyclic aromatic hydrocarbons, monosubstituted benzenes, anilines, phenols, Tanaka tests solutes, fluoroquinolones, and flavonoids as probes. Mechanisms involved in the chromatographic separation included hydrophobic, π-π and π-electron transfer, hydrogen bonding, and inclusion interactions. Moreover, the column was successfully employed for the analysis of the illegal additive of melamine in milk product. [ABSTRACT FROM AUTHOR]

S treptomyces transglutaminase ( TGase) is secreted as a zymogen (pro- TGase) in liquid cultures and is then processed by the removal of its N-terminal region, resulting in active TGase. To date, there is no report describing TGase (or pro- TGase) secretion in E scherichia coli. In this study, the pro- TGase from S treptomyces hygroscopicus was efficiently secreted by E . coli BL21( DE3) using the TGase signal peptide or the pel B signal peptide. The secreted pro- TGase was efficiently transformed into active TGase by adding dispase to the culture supernatant of the recombinant strains. Mutational analysis showed that deletion of the first six amino acids of the N-terminal of the pro-region reduced the secretion of pro- TGase, and removal of the next 10 amino acids resulted in the formation of insoluble pro- TGase. These results suggest that the pro-region of TGase is essential for its efficient secretion and solubility in E . coli. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, a novel section-wise exploiting modification direction (EMD) method is proposed. By using section-wise strategy, the proposed method combines several pixel groups of the cover image together to indicate adjusting modification directions. In each group, the data hiding is performed by the EMD method. Theoretically, we have proved that the modification directions of our section-wise approach is far from the EMD method. The experimental results show that the section-wise strategy can improve the embedding efficiency and the visual quality further than the EMD method, and reduce the possibility of detection. [Copyright &y& Elsevier]