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Androgenetic alopecia (AGA) is a chronic and progressive form of hair loss characterized by vascular degeneration in the perifollicular microenvironment, leading to cell apoptosis and eventual loss of hair follicles (HFs). Traditional therapeutic formulations, such as Minoxidil (MXD) tincture, have limitations in reshaping the perifollicular microenvironment and exhibit limited effectiveness. Here, we report a multi-synergistic therapeutic platform for high-performance hair regeneration therapy. The platform combines microneedle (MN) patches loaded with MXD-encapsulated nanostructured lipid carriers (MXD-NLC-MNs) and cold atmospheric plasma (CAP). The MNs' mechanical strength enables efficient transdermal delivery of MXD to the targeted dermal papilla cells, promoting cell proliferation. Furthermore, in collaboration with MXD, the mechanical stimulation exerted by MN application synergistically upregulates the expression of vascular endothelial growth factor, leading to neoangiogenesis. Meanwhile, the transient microchannels in the skin created by MNs facilitate the transdermal delivery of CAP-generated nitric oxide (NO) to the sites of HF lesions, whereby the synergistic interaction between MXD and NO boosts perifollicular vasodilation. Consequently, the perifollicular microenvironment can be effectively reshaped to accelerate hair regeneration in AGA murine models. This multi-synergistic combination therapy strategy would hold great promise for effectively treating AGA and promoting hair regrowth. [ABSTRACT FROM AUTHOR]

Wet-tissue adhesives have long been attractive materials for realizing complicated biomedical functions. However, the hydration film on wet tissues can generate a boundary, forming hydrogen bonds with the adhesives that weaken adhesive strength. Introducing black phosphorus (BP) is believed to enhance the water absorption capacity of tape-type adhesives and effectively eliminate hydration layers between the tissue and adhesive. This study reports a composite patch integrated with BP nanosheets (CPB) for wet-tissue adhesion. The patch's improved water absorption and mechanical properties ensure its immediate and robust adhesion to wet tissues. Various bioapplications of CPB are demonstrated, such as rapid hemostasis (within ~1-2 seconds), monitoring of physical-activity and prevention of tumour-recurrence, all validated via in vivo studies. Given the good practicability, histocompatibility and biodegradability of CPB, the proposed patches hold significant promise for a wide range of biomedical applications. The utility of wet-tissue adhesives has been impeded by the suboptimal adhesive strength. Here the authors report a composite patch integrated with BP nanosheets that improve the wet-tissue adhesion by enhancing the water absorption and mechanical properties of the patch and demonstrate the uses of the patch in hemostasis, physical-activity monitoring and tumour-recurrence prevention. [ABSTRACT FROM AUTHOR]

The leakage of shield tunnels built in confined aquifers of silt or fine sand may result in the erosion of soil. Due to the loss of ground support, significant distortions of the tunnel structure may arise. As an initial insight into the mechanisms driving disaster chains, the erosion morphology of silt or fine sand under converging flow should be made clear first. In this study, a series of laboratory tests were performed to investigate the erosion morphology of fine sand under converging flow and its spatiotemporal evolution. Notably, for consistency with practical engineering, the initial effective stress of the soil was also considered. The initial results indicated that the erosion process may involve the soil arching effect due to the presence of soil effective stress. On this basis, tests with two leakage points were conducted. It was found that successively opening the two leakage points may lead to a larger erosion area of superposition when compared with the case of simultaneously opening two leakage points. [ABSTRACT FROM AUTHOR]

In order to improve machining efficiency and quality of aero-engine blisks, a novel multi-spindle 5-axis machine tool is developed under the inspiration of the blisk structure. The proposed machine contains 8 spindles, which are arranged radially along the blisk and simultaneously participate in machining. The actuator of the machine contains three rotation axes and two translation axes, which can realize 5-axis CNC machining. Based on the unified kinematics model, the mechanism is analyzed in terms of forward and inverse kinematics, singularity, and flexible workspace. Meanwhile, the structural parameters of the machine are optimized according to the flexibility index to improve the kinematic performance of the mechanism. Theoretical and experimental results show that the machine tool has a more compact structure, fewer moving axes, and better kinematics performance, compared with the traditional multi-spindle modular machine tool. Therefore, the machine has significant advantages in processing efficiency and has great application potential in large batch machining of the blisk. [ABSTRACT FROM AUTHOR]

Blade is the core component of aero-engine, and its manufacturing capability improvement has always been the focus of aviation manufacturing industry. With the high-efficiency machining of multi-spindle machine tool, this paper proposes a synchronous polishing method based on the cluster grouping of actual blade profile. Firstly, the multi-spindle machining system, flexible polishing with determined path, and synchronous polishing process cycle are analyzed in detail. Secondly, the allowable difference within group is determined by the relationship of polishing compression and surface roughness/removal. Then, the distribution of grouping mark points is determined by the profile differences of sampled blades. Thirdly, the consistency of each two blade profiles is expressed as the vector difference of measurement data, and the grouping result can be established with the Ray-Turi index. Finally, a typical blade is used to demonstrate the effectiveness and efficiency. After multi-spindle synchronous polishing, the average synchronous polishing cycle time is 3.14 times less than single-spindle machine tool, the profile error and its difference are less than 0.0685 mm and 0.048 mm, the surface roughness can satisfy Ra ≤ 0.4 μ m , which can meet the design requirement of aero-engine blade. [ABSTRACT FROM AUTHOR]

The aero-engine blade is typically a thin-walled part with poor rigidity and a complex structure. This causes aero-engine blades to be susceptible to flutter and deformation during the machining processing, leading to the dimensional and positional accuracy outside the stipulated tolerance values. With the aim of improving the machining precision of the blades, the conventional blade processing methods were analysed in this study. Based on the analysis, a novel deformation control method named reverse segment machining method was proposed. Additionally, a stress-free auxiliary fixture was designed to improve the stiffness of thin-walled parts. Finally, an experiment was conducted to study the effectiveness of the developed reverse segment method and the stress-free auxiliary fixture in comparison to the forward machining methods. The results show that they can significantly improve machining precision. [ABSTRACT FROM AUTHOR]

Contact calculation is of great importance in predicting the material removal (MR) of flexible grinding process (FGP). The contact is mostly considered approximately constant in the existing MR models, while the situations that contact varies a lot after FGP are ignored. Therefore, a novel model is proposed in this paper to take those situations into consideration. Firstly, the nonconstant-contact situation is introduced. Then, an equivalent method is developed to convert the nonconstant-contact grinding process into the accumulation of several quasi-constant-contact grinding processes. Based on the equivalent method, a MR model is established, and the procedure to obtain the model parameters by the finite element analysis (FEA) is introduced. In the end, the equivalent method and the MR model are tested by a series experiments of different process parameters. Results show that the proposed MR model can predict the material removal effectively for the nonconstant-contact situations. [ABSTRACT FROM AUTHOR]

The sculptured surface has been widely used in aerospace and machinery manufacturing industries. CNC machining of sculptured surfaces is an important research area, and computation efficiency improvements are considered critical topics in this field. This paper presents a highly efficient method to generate smooth tool paths by establishing a mathematical model to describe the relationship between the relative curvature of sculptured surface and the machining strip width in five-axis machining. The method is improved from the middle-point error control method (MPECM) and the feasible tool position surface method (FTPSM), by changing the objective from the complete optimization for each drive point to the drive points' interpolation. The drive point with the narrowest machining strip width and some sample points is selected to interpolate the remaining points. Both theoretical analysis and test examples show the correctness of the proposed method. Under the same condition, compared with the MPECM and the FTPSM, the computing time of the new method decreases to 10% at least. Besides, the fluctuation of the tool path is reduced. The machining examples verified the superiority of the proposed method. [ABSTRACT FROM AUTHOR]

Trichomes are differentiated epidermal cells and can be found on above ground organs of nearly all land plants. Results from previous studies show that trichomes play important roles against a wide range of both biotic and abiotic stresses. By examining differences between parental genotypes of available populations, we identified a population of recombinant inbred lines showing clear segregation for trichome density and length. Assessing the F8 lines of the population growing in the field detected a major locus on chromosome arm 4BL. This locus was detected based the assessments of either fully expanded third leaves or flag leaves after anthesis. Based on the position of the QTL, an SSR marker was used to identify heterozygous plants at this locus from F5 lines derived from the same cross for the F8 population. Three pairs of near isogenic lines targeting this locus were obtained from these heterozygous plants. Difference in trichome length between the two lines with opposite alleles for each of these NIL pairs were similar to that between the two parental genotypes for the mapping populations, confirming that this single locus is mainly responsible for the trichome characteristics measured in this study. The allele with long and dense trichome is dominant as this characteristic was shown by the heterozygous individuals at this marker locus. Apart from the targeted locus, NIL pairs have highly homogeneous genetic backgrounds. Thus, the NILs could be invaluable in understanding the relationship between trichome density and resistance or tolerance to various biotic and abiotic stresses. [ABSTRACT FROM AUTHOR]

Widespread aeolian deposits on the Tibetan Plateau (TP) have provided valuable palaeoclimatic information. However, the primary factors (e.g., climate factors, human activity, and vegetation cover) controlling aeolian deposition remain elusive. In this paper, we use a dataset that comprises new and published ages of Holocene aeolian sand and loess in the middle reaches of the Yarlung Zangbo River to identify the primary controlling factors and palaeoclimatic implications of aeolian deposition. Several intervals of enhanced aeolian accumulation centered at 8.5–7.8, 6.4–5.8, 4.5–4.0, 3.1–1.8, and 0.9 ka are identified, generally consistent with regional low rainfall events and weak Indian summer monsoon (ISM). This suggests that regional wetness, dominated by the ISM, may play a key role in modulating dust emissions and aeolian deposition on centennial timescales. Our results show that on centennial- to millennial-scales, ISM activity can be reconstructed by non-continuous aeolian deposits in the monsoon dominated TP. [ABSTRACT FROM AUTHOR]

As a result of the recently increasing demands on high-performance machining technology in the aero-engine industry, the near-net shape forming technique can be suitable for many integrated impellers. However, the previous forming deformation can raise serious problems for the secondary NC machining of non-formed area, which is mostly applicable for leading/trailing edge (LE/TE) and its adjacent area. It is even worse that non-designed shape and dimension of LE/TE may be responsible for the deteriorated aerodynamic performance and subsequent high in-service cost, especially when its radius is small. Based on previous efforts, this paper presents a 5-axis adaptive machining framework for the LE/TE of near-net-shape integrated impeller. On-machine measurement (OMM) with a touch-trigger probe is utilized to digitalize the impeller. The distribution and uncertainty of sampling points are taken into account with data processing. Through the comparison between the measured and nominal geometric parameters, the impeller profile can be reconstructed sequentially on each tandem cascade. Among this, the camber line deformation emphasizes the functional significance of design intent and the thickness distribution conforms the processed data at most degree. Utilizing the ability to remove small allowance and the low continuous grinding force, the 5-axis CNC grinding with electroplated cubic boron nitride (CBN) wheel is carried out. Moreover, typical examples are used to demonstrate the effectiveness and superiority of this strategy. [ABSTRACT FROM AUTHOR]

Napier grass (Pennisetum purpureum Schum.) is an economically important species used as a fodder crop, reflecting its high biomass, perennial nature and pest resistance. In order to understand the genomic information and development of this species based on SSR markers, the transcriptome for Napier grass was obtained using next-generation sequencing. A total of 117,076 sequence contigs were obtained, with lengths of 201-10,652 bp. Among these contigs, 44,313 (37.85%) sequences were annotated against public protein databases (E-value <10). In addition, the contigs generated from the transcript sequencing were also analysed for the presence of simple sequence repeats (SSRs). A total of 12,744 SSR motifs were identified with in these contigs and corresponding primer pairs were designed. Empirical validation of a cohort of 200 SSRs was performed, with 34% being polymorphic for 20 Napier grass accessions. The polymorphic index content values for each primer ranged from 0.105 to 0.749, with an average of 0.409. The development of genetic, genomic resources and EST-SSRs for Napier grass will contribute to novel gene discovery and the marker-assisted selective breeding of this species. [ABSTRACT FROM AUTHOR]

In five-axis machining, multipoint tool orientation has the merit of getting a wider strip width. However, large computing time restricts its application. In this paper, for machining free-form surfaces by toroidal tools, a highly efficient and convergent multipoint tool orientation optimization method is proposed. The method is improved from Middle Point Error Control Method (MPECM), by changing the objective from the maximum strip width to multipoint tool orientation. H-function is defined, and the consistency between multipoint tool orientation and H-function's zero is demonstrated. Based on that, the seeking for optimal tool orientation is equivalent to the computation of H-function's zero. Under the same conditions, compared with MPECM and mechanical equilibrium method (MEM), the computing time of the proposed method decreases to 5% at least. Convergence is ensured by the analysis of the existence of multipoint tool orientation. In the end, the proposed method is validated in machining a mold surface and an aero-engine blade. [ABSTRACT FROM AUTHOR]

Avoiding significant fluctuations of tool orientation is an important problem in five-axis machining. The dramatic change of tool orientation may greatly increase the angular acceleration of machine rotary axes, produce larger nonlinear machining errors and gouging, reduce the feed rate of machine rotary axes, etc. In this paper, we propose a tool orientation smoothing method based on machine rotary axes for five-axis machining with ball end cutters to reduce fluctuations of tool orientation in the machine coordinate system (MCS). The core idea of the proposed method is to directly smooth machine rotary angles in the machine coordinate system for the smooth variation of tool orientation. First of all, we establish the relationship between the design variables of tool position and machine rotary angles. Then, we define an objective function of tool orientation smoothing based on machine rotary angles. In order to solve the above objective function, we also develop a simplified algorithm to obtain the minimum sum of squares of compound angular accelerations. Finally, a blade surface is used as a test example, and tool paths are generated by the Sturz and proposed methods, respectively. Comparison and analysis results show that the proposed method can improve the kinematics performance of five-axis machine tool, as well as surface machining quality and efficiency. [ABSTRACT FROM AUTHOR]

The cutter posture optimization in five-axis machining is of importance for machining efficiency and quality. In order to achieve a cutter posture with wide strip width, this paper proposes a mechanical equilibrium-based method. When the defined middle point on the cutter is fixed, two contact points are needed and obtained for seeking an equilibrium state of the cutter. After initially positioned on the desired surface, the cutter is firstly stressed by the gravity, then impact on the desired surface. The process repeats until the cutter is in an equilibrium state. The uplift of the cutter is also optimized to avoid excess that caused by the shift of the actual middle point on the error distribution curve. In the implementation, the proposed method distinctly increases the strip width compared with two existing methods. [ABSTRACT FROM AUTHOR]

This paper presents a method to reduce the fluctuation of machining strip width by modifying tool position. When the machining strip width varies rapidly within a tool path, the fluctuation of cutting force brings negative influence on the workpiece and cutter. Furthermore, as the tool path interval is always defined conservatively to avoid undercut, the machined strips of adjacent tool paths have unnecessary amount of overlap. Rapid changing machining strip width usually creates too much overlap at some location, which causes repeated cutting. A method is proposed to modify tool position and reduce the fluctuation of machining strip width. Besides, tilt angle smoothness along the tool path is also taken into account. The computation result of a blade surface verified the validity of the proposed method. [ABSTRACT FROM AUTHOR]

The multi-point tool positioning algorithms produce much larger machining strip width than the single-point algorithms and apparently reduce the actual machining time. This paper presents a tool positioning algorithm for multi-point machining of sculptured surface, which is excellent at dealing with both of concave and convex surfaces. The proposed method is based on the middle-point error control (MPEC) method, which means the connection point between cutter and surface corresponds to the middle point of error distribution curve. Usually, only one cut contact (CC) point can be obtained with this method. Thus, the proposed method improved the MPEC method for achieving two CC points. At first, the shape of error distribution curve is investigated, and its asymmetry is evaluated. Secondly, the error distribution curve becomes symmetrical after the cutter is rotated with a roll angle, and the cutter is separated with surface at the same time. Finally, the minimum tilt angle is found, and two CC points are obtained without gouging. Machining experiment is conducted to verify the proposed method, and the result reveals that the machining strip width is increased apparently and the tool position is almost unchanged after the adjustment with proposed method. Simulation, measurement, and analysis are also given in the part of the experiment. [ABSTRACT FROM AUTHOR]

Maximizing bichromatic reverse nearest neighbor (MaxBRNN) is a variant of bichromatic reverse nearest neighbor (BRNN). The purpose of the MaxBRNN problem is to find an optimal region that maximizes the size of BRNNs. This problem has lots of real applications such as location planning and profile-based marketing. The best-known algorithm for the MaxBRNN problem is called MaxOverlap. In this paper, we study the MaxBRNN problem and propose a new approach called MaxSegment for a two-dimensional space when the $$L_2$$-norm is used. Then, we extend our algorithm to other variations of the MaxBRNN problem such as the MaxBRNN problem with other metric spaces, and a three-dimensional space. Finally, we conducted experiments on real and synthetic datasets to compare our proposed algorithm with existing algorithms. The experimental results verify the efficiency of our proposed approach. [ABSTRACT FROM AUTHOR]

The grindability of high-temperature alloy by using ceramic alumina wheels is studied on the basis of extensive analysis of the grinding force, grinding temperature, surface roughness and topography of ground surfaces, residual stress, hardness distribution of surface layer, and morphology of the surface layer from a metallographic point of view. The grinding burn mechanism of high-temperature alloy is unveiled and the feasible grinding parameters to avoid burning are analyzed. Some conclusions are obtained as follows. Increasing the grinding depth or the wheel velocity makes grinding temperature and residual tensile stress of the surface rise, which deteriorates the surface topography. Appropriate liner velocity of the wheel is 18–22 m/s and the depth of grinding should not exceed 0.02 mm in grinding GH2132 alloy with ceramic alumina wheels to assure the surface quality. When a p increases enough to cause grinding burn, the strengthening effect of particles γ′ in γ base decrease and the micro-hardness of the surface is obviously lower than that of the base material, which deteriorates the mechanical properties and heat resistance of GH2132 alloy. Results provide a theoretical and experimental basis for technical optimization in the grinding of high-temperature alloy with high efficiency and high quality. [ABSTRACT FROM AUTHOR]