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The respiratory tract is the portal of entry for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Although a variety of respiratory pathogens other than SARS-CoV-2 have been associated with severe cases of COVID-19 disease, the dynamics of the upper respiratory microbiota during disease the course of disease, and how they impact disease manifestation, remain uncertain. We collected 349 longitudinal upper respiratory samples from a cohort of 65 COVID-19 patients (cohort 1), 28 samples from 28 recovered COVID-19 patients (cohort 2), and 59 samples from 59 healthy controls (cohort 3). All COVID-19 patients originated from the earliest stage of the epidemic in Wuhan. Based on a modified clinical scale, the disease course was divided into five clinical disease phases (pseudotimes): "Healthy" (pseudotime 0), "Incremental" (pseudotime 1), "Critical" (pseudotime 2), "Complicated" (pseudotime 3), "Convalescent" (pseudotime 4), and "Long-term follow-up" (pseudotime 5). Using meta-transcriptomics, we investigated the features and dynamics of transcriptionally active microbes in the upper respiratory tract (URT) over the course of COVID-19 disease, as well as its association with disease progression and clinical outcomes. Our results revealed that the URT microbiome exhibits substantial heterogeneity during disease course. Two clusters of microbial communities characterized by low alpha diversity and enrichment for multiple pathogens or potential pathobionts (including Acinetobacter and Candida) were associated with disease progression and a worse clinical outcome. We also identified a series of microbial indicators that classified disease progression into more severe stages. Longitudinal analysis revealed that although the microbiome exhibited complex and changing patterns during COVID-19, a restoration of URT microbiomes from early dysbiosis toward more diverse status in later disease stages was observed in most patients. In addition, a group of potential pathobionts were strongly associated with the concentration of inflammatory indicators and mortality. This study revealed strong links between URT microbiome dynamics and disease progression and clinical outcomes in COVID-19, implying that the treatment of severe disease should consider the full spectrum of microbial pathogens present. • The URT microbiome exhibits complex and changing patterns during COVID-19. • A series of microbes are identified to be associated with more severe disease stages. • There are strong links between URT microbiome dynamics and disease progression. [ABSTRACT FROM AUTHOR]

Sarcopenia involves in the loss of muscle mass associated with aging, which is the major cause of progressive muscle weakness and deterioration in older adults. Muscle atrophy is a direct presentation of sarcopenia, and it greatly contributes to the decline in quality of life among older adults. Neuromuscular junction (NMJ) stability is the key link to maintain muscle function. Besides, the degenerative change of NMJ promotes the process of muscle atrophy in the elderly. Based on previous transcriptome sequencing and bioinformatics analyses of aged muscle, this study used the 18-month-old aged mouse model and the 6-month-old young mouse model to deliberate the role and underlying mechanisms of Cullin-3 (Cul3) in age-related muscle atrophy. The results of reverse transcriptase polymerase chain reaction (RT-PCR) and immunoblotting analysis showed that the expression of CUL3 increased in aged muscle tissue, while the expression level of postsynaptic membrane nicotinic acetylcholine receptors (nAChRs) decreased significantly, which manfested a negative correlation. Meanwhile, immunofluorescence demonstrated that Cul3 was highly expressed in senile muscle NMJ. The results of ubiquitin indicated that the ubiquitin level of aged muscle nAChRs was evidently increased. Co-immunoprecipitation furtherly verified the correlation between Cul3 and nAChRs. Taken together, Cul3 may mediate the ubiquitination degradation of nAChRs protein at the NMJ site in aged mice, leading to NMJ degeneration and accelerated atrophy of fast-twitch muscle fibers in aged muscle. As a prominent element to maintain the stability of NMJ, Cul3 is supposed to be one of candidate intervention targets in sarcopenia. • To investigate the expression, role and potential mechanism of Cullin-3 (Cul3) in age-related muscular atrophy. • Clarify the correlation between Cul3 and nAChRs, Cul3 may be involved in ubiquitin degradation of nAChRs at the NMJ site. • Cul3 mediated NMJ degeneration may lead to accelerated atrophy of muscle fibers in aging muscles, leading to sarcopenia. [ABSTRACT FROM AUTHOR]

• Weld morphology characteristics of circular oscillating laser beam welding (OLBW) was illustrated; • Variations of keyhole characteristics and molten pool morphology of circular OLBW were elucidated; • Flow pattern of circular OLBW at distinct moments was described. Many studies have identified the periodicity of oscillating laser beam welding (OLBW), but they do not provide a deep perspective to show the periodic changes of molten pool and keyhole characteristics. In the process of circular OLBW, the spatters were easily formed due to the unstable melt generated by rapid change in keyhole velocity, and its number was prone to decrease with the increase of frequency. The computational fluid dynamics (CFD) method successfully predicted the cross-section morphology of the weld, and the prediction deviation was small. In a single cycle, the fusion state between the newly generated melt and the existing molten pool determined the morphology of molten pool boundary, showing a 'W-U-W' shape change. The keyhole first destabilized and then stabilized again, and its depth exhibited a 'V' shape. The average flow velocity of the melt in the longitudinal section of the weld or keyhole center presented a 'W' shape. The keyhole depth or the average melt velocity period was equal to the oscillation period of circular OLBW. [ABSTRACT FROM AUTHOR]

The flow characteristics, bubble formation and inhibition mechanisms of circular oscillating laser beam welding (OLBW) at distinct stages were elucidated in present work. The formation processes of bubbles mainly included the following manners. First, one or more of vortex P2, the recoil pressure flow P3, the migration flows FMF and BMF impinged the keyhole wall. The necking generated, gradually destabilized, and finally collapsed. Second, the self-instability of needle-like keyhole bottom (NKB) with large curvature induced the bubble formation. Third, complex melt flow broke the abnormal deformation of the keyhole or the bubble wall to form a new bubble. The bubble suppression mechanisms were summarized to three categories. First, the recoil pressure on the inner wall of bubble was at a low level, and the volume of bubble continually decreased until it collapsed. Second, high recoil pressure penetrated the metal liquid bridge between keyhole and bubble. Third, when recoil pressure was greater than the resultant force between surface tension and melt dynamic pressure, the bubble constantly fluctuated and gradually merged with the moving keyhole. As the frequency increased from 10 Hz to 200 Hz, porosity showed an exponential decrease from 7.16% to 0.35% in circular oscillation mode. A unified porosity prediction curve based on the Reynolds number was built with a coefficient of determination of 0.989. When fluid changed from laminar to turbulent flow, the critical Reynolds number was set as 1000, the predicted porosity was 0.912%, and the critical frequencies in circular and infinite oscillation modes were 143 Hz or 115 Hz, respectively, which were consistent with experiment results. [ABSTRACT FROM AUTHOR]

The deformation behavior and microstructure characteristics of laser-welded Ti-6Al-4V titanium alloy joints under variable amplitude fatigue ranging from 320 to 380 MPa (initial maximum stress) were investigated in steps of 10 MPa. Each fatigue test included three different stages: the maximum stress amplitude was initial one for the first stage, but increased by 1.2 and 1.4 times for the second and third stages, respectively. The results showed that the variable amplitude fatigue limit of laser-welded the Ti-6Al-4V joint was 339 ± 5 MPa. Fractography analysis revealed that the fatigue cracks originated from the surface in the weld metal (WM) and were caused by the differences of grain size and texture orientation between WM and heat-affected zone. The average grain size of WM was significantly larger than that of other regions. Acicular α' martensite was distributed mainly in the coarse grains of WM and its orientation was more concentrated, leading to the preferred orientation. Furthermore, the accumulation of dislocations on the acicular α' and β phase interface led to fatigue crack initiation owing to stress concentration. In addition, the lager average Schmid factor and smaller deviation in WM of the joint at a large stress amplitude was owing to the smaller relative geometrical orientation. • The variable amplitude fatigue behavior of laser-welded Ti-6Al-4V joint was studied. • Differences in grain size and orientation lead to joint fracture in weld metal. • Dislocations accumulated on the phase interface are key elements leading fracture. • The characteristics of joint microstructure and fracture behavior are related. [ABSTRACT FROM AUTHOR]

The formation control problems of small fixed-wing(FW) unmanned aerial vehicles (UAVs) are investigated in this paper. By adopting a simplified aerodynamic force model and a cascade control structure, the horizontal motion of a FW UAV can be described as a linear system with uncertainties based on the feedback linearization technique. Thereafter, a novel robust formation protocol is proposed, which incorporates two components: the nominal controller and the robust filter-based compensator to restrain the influences of equivalent uncertainties. It turns out the formation error can converge to a sufficiently small neighborhood of the origin. The stability of the closed-loop system is proved in combination with classic Lyapunov-based arguments. Finally, field formation flight experiments on four small FW UAVs are carried out to demonstrate the effectiveness of the theoretical results. [ABSTRACT FROM AUTHOR]

Rhipicephalus microplus is considered to be the most important tick infesting cattle, buffalo, horse, goats as well as other animals. They transmit diseases between domestic animals and act as vectors of a variety of zoonotic pathogens. Although pathogens harbored by R. microplus have been extensively studied, the Rickettsiales pathogens vectored by R. microplus in some areas of China remained largely unexplored. From August to October 2020, a total of 291 R. microplus ticks were collected from goats and cattle in three Southern China provinces, Guangxi (n = 138), Sichuan (n = 120) and Hubei (n = 33) provinces. Phylogenetic analysis based on COI gene sequences shows that these ticks are divided into three distinct clades, indicating the remarkable genetic diversity of R. microplus ticks in China. These samples were subsequently screened for the presence of Rickettsia, Anaplasma and Ehrlichia using conventional PCR and sequencing. Subsequently, five bacterial species were identified. Out of the 120 tick DNA samples from Sichuan province, 35.83% (43/120) were positive for Rickettsia sp. belonging to spotted fever group (SFG), 12.50% (15/120) were positive for Anaplasma marginale and 0.83% (1/120) was identified as A. platys. From the 138 DNA samples from Guangxi province, an Ehrlichia canis -like and Rickettsia sp. were detected, with a positive rate of 11.59% (16/138) and 2.17% (3/138), respectively. A. capra DNA was detected in 4 out of 33 (12.12%) samples from Hubei province. Notably, the 16S, gltA and groEL sequences of the E. canis -like are closely related to the E. canis strain previously identified from China, and form a distinct cluster in the phylogenetic trees. Collectively, our results expand the knowledge on tick-borne Rickettsiales pathogens in China. Because the state of engorgement of ticks was not recorded, it is not clear at this stage whether these pathogens are infecting the ticks or are simply present in the blood meal. Given the public health significance of SFG Rickettsia, A. capra, A. platys and E. canis , a thorough investigation of the diversity and presence of pathogens in R. microplus in areas with tick-associated diseases are needed. [ABSTRACT FROM AUTHOR]

Abstract: Graphene layers have been produced from multi-walled carbon nanotube (MWCNT) bulk materials by friction when polished on ground-glass, offering a novel and effective method to produce graphene layers, which, more importantly, could be transferred to other substrates by rubbing. Field emission scanning electron microscopy, Raman spectroscopy, atomic force microscopy, transmission electron microscopy and selected area electron diffraction confirmed the formation of graphene layers. They were thought to be peeled away from the MWCNT walls due to friction. The reflection spectra showed that absorption of as-produced graphene layers decreased with wavelength in the range of 250–400nm, compared to the MWCNT bulk material having strong absorption at 350nm. Nanoscratch test was used to determine the mechanical properties of graphene films, suggesting the tolerance of as-produced graphene film to flaws introduced by scratch. [Copyright &y& Elsevier]

Due to the lack of structure and part information in non-cooperative targets, the task of pose estimation suffers from unstable and unreliable initial coordinate system. In this paper, we introduce a curve-skeleton-based method to construct the robust coordinate system automatically for non-cooperative targets. First, a nonmanifold-Laplacian-based method is proposed to extract the curve skeleton from point clouds. The proposed method solves the over-contraction problem while preserves the topology and structure of skeleton well during point clouds contraction. Additionally, we create the skeleton graph to detect the skeleton structure and key points automatically. Then, the detected skeleton feature is used to construct target coordinate system, and improve the stability and robustness. Specifically, a real-scan dataset is constructed in this paper, and the proposed point cloud contraction method outperforms previous methods in structural representation and visualization. The mean rotation error of proposed coordinate system construct method performs 0.1249° and 1.2135° in 0%–30% noise ratio of distortions and outliers, and performs 7.04° and 4.21° in real-scan aircraft and satellite datasets. The results in complete and incomplete datasets verify the robustness and reliability of our skeleton-based coordinate system. • We introduce the local contraction state and solve the over-shrinkage. • We construct the skeleton-based coordinate system for non-cooperative targets. [ABSTRACT FROM AUTHOR]

• Applied Laser-induced graphene based thermal meta-shell encircled temperature sensor for the first time. • The sensor provided a high accuracy with a deviation of only 0.21 K and a fast response time of 1.15 s. • The sensor exhibits controllable thermal conductivity, insensitive to humidity and vibration, and low cross sensitive to bend. Accurate temperature measurement is critical in various fields, particularly in new energy vehicle power batteries and biomedicine. However, placing a temperature sensor in a thermal field can cause perturbations that lead to inaccuracies in measurement, which can have severe consequences. To address this issue, a Laser-induced graphene (LIG) based meta-shell encircled temperature sensor was proposed that takes advantage of the controllable thermal conductivity of LIG. The sensor's thermal measurement capabilities are theoretically analyzed, and the proposed approach is shown to eliminate thermal perturbations caused by the mismatch between the sensor and background, resulting in more accurate measurements. The effects of different laser processing parameters on the alteration and enhancement of LIG thermal conductivity have also been experimentally demonstrated for constructing the thermal meta-shell. The high-accuracy of the proposed sensor was experimentally verified by comparing the temperature differences with a bare sensor. The meta-shell encircled sensor showed a maximum thermal deviation of only 0.21 K, while the bare sensor produced a deviation of 1.55 K. Furthermore, the LIG-based sensor can maintain high accuracy in a high-temperature environment exceeding 410 K, and its stability and repeatability have been experimentally verified. The sensor also shows a fast response time of 1.15 s and can maintain accurate temperature measurement under large curvature (0.4 m−1), insensitive to humidity and vibration, proving its applicability in complex situations. The proposed LIG-based meta-shell encircled temperature sensor is manufactured through laser direct writing method and is easy to mass-produce, making it highly promising for high-accurate temperature monitoring applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Mg 2 Sn formation and growth was found mainly occurred during the cooling stage. • The Mg 2 Sn thickness was inhibited to less than 5 μm by using water-cooling. • The joint strength was improved greatly with water-cooling than that of air-cooling. • The fracture location changed from the IMC layer to the solder with water-cooling. Magnesium and aluminum alloys are widely used in various industries because of their light weight and other properties. However, Mg–Al intermetallic compounds (IMCs) decrease the joint properties of Mg/Al, which limits its applications. Here, the alloys AZ31 Mg and 6061 Al are soldered together with Sn and Sn–9Zn solders though different cooling rates via ultrasonic-assisted soldering to control IMC formation and growth. Results show that this prevents formation of Mg–Al IMCs such as Al 3 Mg 2 and Al 12 Mg 17 ; however, Mg 2 Sn forms in the soldered joints. The Mg 2 Sn thickness increases with soldering temperature, which reduces joint strength. The thickness is reduced using the Sn–9Zn solder, and the effect of Zn is analyzed. With the use of water-cooling, the Mg 2 Sn formation and growth are inhibited, the Mg 2 Sn thickness is kept below 5 μm, and the shear strength peaks at 53.2 MPa. A soldering model of Mg 2 Sn formation is proposed to reveal the evolution and inhibition mechanism of Mg 2 Sn. This study well controls IMC thickness and improves joint strength, thus expanding industrial application of Mg–Al dissimilar metals and providing a feasible method for controlling IMCs in dissimilar metal joining. [ABSTRACT FROM AUTHOR]

MXene (Ti 3 C 2 T x) is an important category of two-dimensional (2D) materials due to its distinctive metallic conductivity and adjustable surface chemistry. The exceptional benefits of heterointerface and defects or viods, combined with the distinct electromagnetic (EM) properties, inject boundless potential into the advancement of MXene-based absorbers for EM absorbing materials. However, conventional synthetic methods depend on chemical etching of MAX powders (Ti 3 AlC 2) using hazardous HF or similar substances, resulting in MXene sheets with fluorine termination and limited stability in colloidal dispersions under ambient conditions. Herein, varied synthetic routes were proposed to prepare MXenes with different terminal groups by the fluoride-based salts, fluoride-free molten salts, and alkali etching. 2D MXene nanosheets with abundant surface groups are excellent EM absorbing materials, and the MXene etched by the Lewis acid CuCl 2 delivered remarkable reflection loss (RL) value of −47.56 dB at 2.5 mm and broad bandwidth of 4.8 GHz due to promoted interfacial polarization. By conducting a thorough examination of the structural changes in MXenes, this study aims to propose a viable method for delaminating single-layer MXene and elucidate the EM absorption mechanisms. [Display omitted] [ABSTRACT FROM AUTHOR]

Papillary craniopharyngioma (PCP) was previously believed to occur only in adults. Sporadic pediatric PCP (PPCP) confirmed by detection of BRAF V600E mutation has been reported since 2018, but is often misdiagnosed before being diagnosed definitively. We aimed to evaluate PPCP characteristics and propose diagnostic criteria for prompt diagnosis, seeking to reduce patient morbidity and mortality and reduce costs linked to misdiagnosis. This study included 5 patients with PPCPs whose data were retrieved retrospectively from among 1032 patients with craniopharyngiomas admitted to Sanbo Brain Hospital Management Group from March 2017 to May 2021. Patients' demographics, clinical presentation, tumor imaging characteristics, histopathologic results, surgical approaches, and postoperative outcomes were analyzed. PPCP was misdiagnosed intraoperatively as sellar abscess (n = 4) or Rathke cleft cyst (n = 1). Preoperative magnetic resonance imaging showed that all tumors were under the saddle diaphragm, and the cyst wall was enhanced (n = 5). Computed tomography scans showed scattered high-density signs (n = 4). No recurrence was noted after complete resection. Postoperative hypothalamic dysfunction was mild. BRAF V600E mutation was confirmed in all cases by sequencing and immunohistochemistry. Immunohistochemistry showed granulation and inflammation and MPO, CD3, CD20, CD38, CD68, and CD163 were positively expressed. Misdiagnosis of PPCP is responsible for failed surgical treatment. We propose that prompt diagnosis of PPCP can be achieved if preoperative magnetic resonance images show the tumor under saddle diaphragm with tumor wall enhancement and computed tomography scans show high-density signs scattered in the tumor, which leads to safe, effective tumor resection. Our proposed diagnosis and treatment strategy for PPCP reduces morbidity and mortality. [ABSTRACT FROM AUTHOR]