Homogeneous Spatial Distribution Research Articles

Spatiotemporal variations of PM2.5 organic molecular markers in five central cities of the Yangtze River Delta, East China in autumn and winter: Implications for regional and local sources of organic aerosols

Information on the spatiotemporal variations in the composition and sources of organic aerosols (OA) is needed to identify regional influences and to establish effective control measures. Here, 23-h PM2.5 samples were collected in five central cities of the Yangtze River Delta in eastern China, including Nanjing, Suzhou, Wuxi, Changzhou, and Zhenjiang, every three days from 2020/09/01 to 2021/02/28. Each sample was analyzed for water-soluble inorganic ions, organic carbon (OC), elemental carbon (EC), and organic molecular markers (OMMs). Generally, the major components of PM2.5, including NH4+, SO42−, NO3−, OC, and EC, exhibited similar temporal patterns across the five cities. In all OMM groups, the concentrations of PAHs, oxygenated PAHs, and secondary products of isoprene showed strong correlations (r = 0.79 ± 0.050–0.93 ± 0.028) and low coefficient of divergence (COD = 0.22 ± 0.024–0.30 ± 0.033) between sampling sites, indicating a homogeneous spatial distribution of industrial emissions and biogenic secondary OA in autumn and winter. Other OMMs showed wider r (e.g., steranes and hopanes, 0.20–0.80) and COD (0.26–0.69) ranges for all site pairs, probably due to the influence of local emissions. Based on the source apportionment results using Positive matrix factorization, the biomass burning factor dominated the contribution to OC and EC in winter and showed strong correlations (r = 0.84 ± 0.063) between the sampling sites, indicating regional transport of emissions from biomass burning and fossil fuel combustion in the heating season. Traffic-related factors had the greatest spatial heterogeneity (r = 0.27 ± 0.19–0.51 ± 0.16) and contributed significantly to OC at their maximum levels.

High-density EMG reveals atypical spatial activation of the gastrocnemius during walking in adolescents with Cerebral Palsy

Children with Cerebral Palsy (CP) exhibit less-selective, simplified muscle activation during gait due to injury of the developing brain. Abnormal motor unit recruitment, altered excitation-inhibition balance, and muscle morphological changes all affect the CP electromyogram. High-density surface electromyography (HDsEMG) has potential to reveal novel manifestations of CP neuromuscular pathology and functional deficits by assessing spatiotemporal details of myoelectric activity. We used HDsEMG to investigate spatial-EMG distribution and temporal-EMG complexity of gastrocnemius medialis (GM) muscle during treadmill walking in 11 adolescents with CP and 11 typically developed (TD) adolescents.Our results reveal more-uniform spatial-EMG amplitude distribution across the GM in adolescents with CP, compared to distal emphasis in TD adolescents. More-uniform spatial-EMG was associated with stronger ankle co-contraction and spasticity. CP adolescents exhibited a non-significant trend towards elevated EMG-temporal complexity. Homogenous spatial distribution and disordered temporal evolution of myoelectric activity in CP suggests less-structured and desynchronized recruitment of GM motor units, in combination with muscle morphological changes. Using HDsEMG, we uncovered novel evidence of atypical spatiotemporal activation during gait in CP, opening paths towards deeper understanding of motor control deficits and better characterization of changes in muscular activation from interventions.

Lipiodol emulsion as a dual chemoradiation-sensitizer for pancreatic cancer treatment

Pancreatic ductal adenocarcinoma (PDAC) has a low survival rate and limited treatment options. Concurrent chemoradiotherapy is considered beneficial to improve tumor control, but the low drug bioavailability at tumor site and the low radiation tolerance of surrounding healthy organs greatly limits its effectiveness. Lipiodol, a natural drug carrier used in clinical transarterial chemoembolization, has shown potential as a radiosensitizer due to its high Z element iodine composition. Thus, this study aims to repurpose lipiodol as a sensitizer to simultaneously enhance chemo- and radiotherapy for PDAC. To this end, a stable lipiodol emulsion (IOE) loaded with gemcitabine is designed using clinically approved surfactants. At in vivo level, IOE demonstrates better radiotherapeutic effect than existing nanoradiosensitizers and enhanced drug bioavailability over free drug, leading to significant tumor inhibition and improved survival rates under concurrent chemo-radiotherapy. This may due to the sustained drug release, homogenous spatial distribution, and long-term retention ability of IOE in solid PDAC tumor. Furthermore, to better understand the functioning mechanism of drug-loaded IOE, in vitro study is conducted to reveal the ROS- and DNA damage-related therapeutic pathways. Lastly, a comprehensive toxicity assessment also proves the good biocompatibility and safety of as-prepared IOE. This study offers a clinically feasible sensitizer for simultaneous chemoradiotherapy and holds potential for other types of cancer treatment in clinics.

Effects of longitudinal profile shape on scour and flow resistance in rills

AbstractThe literature regarding how rill longitudinal profile (concave and convex) affects soil loss and flow resistance is still lacking. The only analysis available in the literature for rills is limited by the fact that measurements were performed for a unique mean slope value sp (18%). In this article, further rill measurements were conducted on a plot with sp = 15% and complex profile shapes and were used to widen the knowledge about the influence of longitudinal profile shape on rill scour, eroded volume, and flow resistance. The findings highlighted that the concave profile has a homogeneous spatial distribution of moderate scours, whereas the scours in the convex one are deeper and more confined, but they are not placed after the slope change as found for sp = 18%. The mean scour depth, which accounts for the discharge and profile shape effects, is not (concave) or is weakly (convex) related to the flow discharge. The concave profile determined a reduction of approximately 57% of the total eroded volume when compared with the convex profile shape, confirming that a concave hillslope limits erosive phenomena. Finally, the flow resistance equation guaranteed a precise estimation of the Darcy–Weisbach friction factor.

From heterogeneous nucleation to homogeneous spatial distribution of hardening precipitates: An in situ TEM study on cold-rolled AA2024-T3 (Al–Cu–Mg)

From heterogeneous nucleation to homogeneous spatial distribution of hardening precipitates: An in situ TEM study on cold-rolled AA2024-T3 (Al–Cu–Mg)

New spin-electronics compositions: Large ferromagnetic order of BaSn0.98-xFe0.02CuxO3 (x = 0.02, 0.04, 0.06) semiconductor

Inducing robust ferromagnetic order in dilute magnetic semiconductor materials is an essential topic for spin-based electronics devices. Herein, the escalating concentration of nonmagnetic Cu ions was employed to strongly reinforce the room temperature ferromagnetism of 2% Fe doped BaSnO3 structure. BaSn0.98-xFe0.02CuxO3 (x = 0.02, 0.04 or 0.06) compositions were prepared by adapted sol gel method. In all compositions, pure single phase with cubic structure of BaSnO3 was identified by the X-ray diffraction (XRD) technique. Pure BaSnO3 gives a band gap energy of 3.25 eV which red shifted to 3.1, 3.12 and 3.13 eV after incorporation of (2% Fe, 2% Cu), (2% Fe, 4% Cu) and (2% Fe, 6% Cu) ions, respectively. The scanning electron microscope (SEM) images reflects that the Fe/Cu blends obstruct the grains growth of BaSnO3 and also influenced on the particles shape and porosity. The energy dispersive X-ray (EDX) maps confirmed the homogenous spatial distribution of Fe and Cu in the codoped BaSnO3 structure. The X-ray photoelectron spectroscopy (XPS) results of BaSn0.92Fe0.02Cu0.06O3 prove that Ba, Sn, O, Fe and Cu elements possess the oxidation states of +2, +4, −2, +3 and +1/+2, respectively. The magnetic performance of BaSnO3 structure exhibits a minor ferromagnetic loop with measured coercivity (Hc) of 330 Oe, magnetization (Ms) of 0.0023 emu/g and retentivity of 0.00077 emu/g. Interestingly, the addition of 6 wt% Cu (nonmagnetic dopant) plus 2 wt% Fe (magnetic dopant) strongly boosts the saturation magnetization value of BaSnO3 to 1.85 emu/g. The results open the door to tune the ferromagnetic order of BaSnO3 using nonmagnetic dopant to avoid the formation of magnetic impurities. The F-center exchange interaction and the bound magnetic polarons model were used to explain the measured room temperature ferromagnetism.

Numerical simulation of friction extrusion: process characteristics and material deformation due to friction

This study employs a finite element thermo-mechanical model, using a Lagrangian incremental setting to investigate friction extrusion (FE) under varying process conditions. The incorporation of rotation in FE generates substantial frictional heat, leading to significantly reduced process forces in comparison to conventional extrusion (CE). The model reveals the interplay between temperature, strain, and strain rate across different microstructural zones of the resulting wire. Specifically, the sticking friction condition in FE enhances initial shear deformation, aligning with a homogeneous spatial strain distribution and predicting complete grain refinement in the extruded wire, as per Zener-Hollomon calculations. On the other hand, under the sliding friction condition in FE, the shear deformation is reduced which results in an inhomogeneous microstructure in the extruded wire. The analysis of material flow in the workpiece reveals distinct transitions from the base material to the thermo-mechanically affected zones. The simulated process force, thermal history, and microstructure during sliding friction conditions align well with the findings from performed friction extrusion experiments.

Regional Sources and CH4 Seasonal Cycle in Central Siberia and the Arctic: Observations and Numerical Calculations

Contributions of anthropogenic and wetland methane emissions in Northern Eurasia (>40° N) and Russia into the near-surface CH4 abundance are quantified using GEOS-chem global chemical transport model at ZOTTO, Teriberka, and Tiksi measurement sites. Numerical results agree well with the proposed semianalytical solution, in which the total contribution (atmospheric response) in the CH4 level at a given site is decomposed into direct (synoptic) and global terms. On an advection timescale corresponding to a synoptic time interval, the annual average direct contribution of Russian anthropogenic emissions into the CH4 mixing ratio measured at ZOTTO (38.6 ppbv) is more than twice as large as that for Western Europe sources (17.7 ppbv). For the Arctic sites, the anthropogenic inputs from Russian and European sources are roughly similar (19.5 and 12.4 ppbv, respectively). The input from continental sources into near-surface methane abundance and its annual variations at the Arctic sites are generally lower compared to those at the ZOTTO site due to larger transport times from upstream CH4 source regions. Model-based atmospheric responses in methane levels at the Teriberka and Tiksi sites to continental CH4 sources are found to be very close owing to the relatively homogeneous (circumpolar) spatial distributions of the anthropogenic and biogenic signals at high latitudes.

Iron oxide/graphene oxide nanocomposite synthesis using atmospheric cold plasma.

Herein, we demonstrate the use of an atmospheric pressure plasma with a Dielectric Barrier Discharge (DBD) for the synthesis of FeOx nanoparticles with a simultaneous formation of graphene oxide domains at low substrate temperature. For that, the interaction of the plasma to control good decomposition of the Fe precursor is essential and this is demonstrated by FTIR analyses. Thanks to a fine tuning of the plasma conditions, a homogeneous spatial distribution around 5 nm nanoparticles (NPs) was obtained, whereas without plasma, in the same configuration of the process, a heterogeneity regarding size and shape for the NPs was obtained. The Raman spectrum of the plasma deposit confirmed the presence of graphene oxide as the characteristic G and D bands were observed with I(D)/I(G) = 0.92. Thanks to optical emission spectroscopy (OES) measurements, it is proposed that the carbon deposition on FeOx nanoparticles is produced on the near plasma post discharge. XPS studies showed that the main contribution of iron was in Fe2+ form, corresponding to the FeO phase. No metallic Fe or carbide were detected. As there are many studies reporting the synergetic effect of FeOx NPs and graphene oxide, we believe that this new one-step simultaneous synthesis method may be of high interest for applications requiring direct deposition on temperature labile substrates such as polymers.

Distribuição espaço-temporal da biomassa e carbono florestal acima do solo em Floresta Tropical Seca sob pressão antrópica, Brasil

The present study aimed to characterize the spatiotemporal variability of aboveground biomass and carbon in two fragments of Dry Tropical Forest in the Brazilian semi-arid region using the kriging interpolation technique. One fragment experienced vegetation suppression for alternative land use, while the other had no history of use or wood extraction. The vertices of 80 plots (20 m x 20 m) were georeferenced, and biomass and carbon were estimated using allometric equations adjusted for Caatinga species. Spatial analyses and mapping of aboveground biomass and carbon were performed using GS+ software, with semivariograms fitted using spherical, exponential, and Gaussian models. The research aims to fill gaps regarding the impacts of inadequate forest exploitation in Dry Tropical Forests, specifically on the spatiotemporal distribution of biomass and carbon, as anthropogenic pressure can cause significant environmental degradation, resulting in reduced stocks. This investigation seeks to elucidate these dynamics and provide insights for management and conservation strategies based on robust empirical data, in addition to answering the following questions: Does the history of anthropogenic interventions in Dry Tropical Forest areas cause variations in the spatial distribution of biomass and carbon stocks that can be detected by the kriging method? Which attributes related to conservation and anthropogenic use reflect the spatial distribution of biomass and carbon stocks in Dry Tropical Forest areas? The results showed a strong spatial dependence of biomass and carbon stocks in both studied areas, indicating the influence of the areas’ use history. The conserved fragment presented a more homogeneous spatial distribution, suggesting that the selective and unauthorized wood extraction was dispersed throughout the area.

Aging response of a Fe–C–Co–Ni secondary hardening steel: The significance of matrix ordering

The evolution of precipitates and dislocations during aging dictates the mechanical properties of secondary hardening steels. Such microstructural response of a Fe–C–Co–Ni secondary hardening steel has been investigated via high-resolution transmission electron microscopy in this study. The primary source of strengthening is linked to coherent Molybdenum carbides, which form in a sequence of cementite, cluster and M2C. It is shown that the ordering of the martensitic matrix occurs rapidly upon aging and results in the formation of dispersed B2–FeCo precipitates. The co-location of ordered domains with the cluster and M2C carbides indicates that the ordering greatly affects the nucleation and growth of M2C and thus leads to a more homogeneous spatial distribution of M2C. This yields excellent mechanical properties including an ultimate tensile strength of 2150 MPa, yield strength of 1829 MPa, and total elongation of 12 %. It should be noted that the ordering not only contributes to the mechanical properties by promoting the dispersion of M2C, it also causes strengthening directly as demonstrated by an additive model of yield strength. However, the model fails to predict the yield strength of the as-quenched sample since it contains extra mobile dislocations which considerably modify the mechanical property.

Ketoprofen-loaded PLGA-based bioactive coating prepared by supercritical foaming on a TiAl6V4 substrate for local drug delivery in orthopedic applications

In this study, a novel biodegradable poly(lactic-co-glycolic) acid coating containing a model anti-inflammatory drug (ketoprofen) was prepared on TiAl6V4 substrate for use in orthopedic medicine by a two-step process combining drop casting and supercritical CO2-assisted foaming. The prepared coating was first investigated by surface analysis techniques using time-of-flight secondary ion mass spectrometry and X-ray photoelectron spectroscopy. The combined results confirmed the loading of ketoprofen and its homogeneous spatial distribution in the coating. 3D profilometry revealed increased surface roughness of the coating compared to the bare TiAl6V4 substrate, which is favorable for cell adhesion. Furthermore, the electrochemical measurements (i.e., electrochemical impedance spectroscopy and potentiodynamic curve measurements) demonstrated that the coating application significantly mitigated corrosion compared to the bare TiAl6V4 substrate. In vitro drug release tests revealed extended drug release in simulated body fluids with zero-order release kinetics. Finally, the promising cell testing results using adipose-derived mesenchymal stem cells and osteoblasts confirmed the applicability of the coating for implants. Overall, the results of this study highlight the significant potential of the developed bioactive coating for future orthopedic applications.

Effect of cold rolling on nucleation, growth and coarsening of S-phase precipitates in Al- Cu- Mg alloy (AA2024): From heterogeneous nucleation to homogeneous spatial distribution

The effect of cold rolling on the precipitation kinetics of the hardening phase has been studied in industrial AA2024. Due to the relatively simple precipitation sequence and the use of the alloy in naturally aged (T3) and peak-aged (T8) states, it was possible to unambiguously analyse the effect of pre-deformation on the nucleation/growth and coarsening of the S-phase. Faster coarsening kinetics due to dislocations induced by cold rolling were observed before the recovery had been completed, leading to lower hardness of pre-deformed AA2024-T8 compared to that without pre-deformation for the same ageing conditions. The nucleation and growth of S-phase were also faster after cold rolling. Moreover, the heterogeneous nucleation resulting from pre-deformation finally led to a fine and homogeneous spatial distribution of hardening precipitates and thus to higher hardness values. Furthermore, cold rolling resulted in a different aspect ratio of S-phase precipitates during both growth and coarsening. The current study was conducted on AA2024, one of the most studied Al-Cu-Mg alloys, where only one equilibrium phase, the S-phase, precipitates, but the findings may be applicable for other precipitation-hardened alloys as well.

Characterization of aperiodic surfaces with mesh-based parameters

For technical surfaces, it is important to know their functional purpose and to characterize them accordingly. Therefore, ISO 21920–2 in 2D and ISO 25178–2 in 3D offer parameters that can assess surface functional properties. The topographic portions of a surface, for example hills and dales, can be classified as features and evaluated using feature parameters. However, no parameter exists to describe the spatial distribution of features with regard to the degree of homogeneity for aperiodic surfaces. Here we show the application of the Delaunay triangulation to quantify the spatial distribution respectively the geometric relationship of features. Therefore, the feature points are determined by watershed analysis and the resulting point cloud is meshed in 2D. Based on that mean and standard deviation of the triangle side lengths and the area disorder (AD) are calculated as new parameters. The method is demonstrated for sandblasted and chrome-plated specimens. In addition simulation is used to generate more data for analysis. With the proposed approach the distinction and extent of uniform, homogeneous or inhomogeneous spatial distributions of features with parameter AD can be determined.

Waffle-inspired hydrogel-based macrodevice for spatially controlled distribution of encapsulated therapeutic microtissues and pro-angiogenic endothelial cells.

Macro-encapsulation systems for delivery of cellular therapeutics in diabetes treatment offer major advantages such as device retrievability and high cell packing density. However, microtissue aggregation and absence of vasculature have been implicated in the inadequate transfer of nutrients and oxygen to the transplanted cellular grafts. Herein, we develop a hydrogel-based macrodevice to encapsulate therapeutic microtissues positioned in homogeneous spatial distribution to mitigate their aggregation while concurrently supporting an organized intra-device network of vascular-inductive cells. Termed Waffle-inspired Interlocking Macro-encapsulation (WIM) device, this platform comprises two modules with complementary topography features that fit together in a lock-and-key configuration. The waffle-inspired grid-like micropattern of the "lock" component effectively entraps insulin-secreting microtissues in controlled locations while the interlocking design places them in a co-planar spatial arrangement with close proximity to vascular-inductive cells. The WIM device co-laden with INS-1E microtissues and human umbilical vascular endothelial cells (HUVECs) maintains desirable cellular viability in vitro with theencapsulated microtissues retaining their glucose-responsive insulin secretion while embedded HUVECs express pro-angiogenic markers. Furthermore, a subcutaneously implanted alginate-coated WIM device encapsulating primary rat islets achieves blood glucose control for 2 weeks in chemically induced diabetic mice. Overall, this macrodevice design lays foundation for a cell delivery platform, which has the potential to facilitate nutrients and oxygen transport to therapeutic grafts and thereby might lead to improved disease management outcome.

A comprehensive study on the processing of Co:ZnO nanostructured ceramics: Defect chemistry engineering and grain growth kinetics

• Co:ZnO samples were prepared from different Co precursor (Co3O4, CoO, and metallic Co) in different sintering atmosphere (oxygen and argon). • First-principles calculations were performed to give support to the defect chemical analysis and insight into the mechanisms of the Co incorporation in the ZnO. • A detailed structural characterization was employed to determine the Co apparent incorporation activation energy and the grain growth kinetic parameters. • The Ar sintering atmosphere promotes an incongruent decomposition of the ZnO, leading to a higher Zn i density and a higher Co solubility. • To achieve high grain growth and densities the Co3O4 demonstrated to be a good additive for the w -ZnO sintering. • In the Ar sintering atmosphere the metallic Co precursor, due to its higher solubility into the w -ZnO, leads to a high Co homogeneous distribution over the w -ZnO grain. • CoO present the lowest solubility into w -ZnO and final grain size, being the best choice for top-down approach in processing of Co-doped w -ZnO nanopowders. In this report, we present a systematic study on the preparation of Co:ZnO ceramics via a standard solid-state route from different Co precursors (Co 3 O 4 , CoO, and metallic Co) and atmospheres (O 2 and Ar). Particular emphasis is given to defect chemistry engineering and the sintering growth kinetics. First-principles calculations based on density functional theory are employed to determine the formation energy of the main point defects in ZnO and Co:ZnO systems. Based on the theoretical results, a set of chemical reactions is proposed. Detailed microstructural characterization is also performed to determine the degree of Co incorporation into the ZnO lattice. The samples prepared in Ar atmosphere and metallic Co present the highest Co solubility limit (lower apparent Co incorporation activation energy) due to the incongruent ZnO decomposition. Determination of the parameters of the sintering growth kinetics reveals that Co 3 O 4 is the best sintering additive to achieve larger grain sizes, and possible higher densities, in both sintering atmospheres, while metallic Co is the best to achieve the smallest grain size with higher Co concentration and homogeneous spatial distribution for a subsequent reduction of dimensionality. The results show that the sintering in O 2 effectively promotes zinc vacancies in the ZnO structure, while the sintering in Ar promotes zinc interstitial defects. Our findings contribute to understanding the preparation of Co-doped ZnO ceramics and the sintering growth kinetics, which may improve the state of the art in processing the material at both bulk and nanometric scales.

Energetic laser-driven proton beams from near-critical-density double-layer targets under moderate relativistic intensities

Double-layer targets composed of near-critical-density carbon nanotube foams (CNFs) and solid foils have shown their advantages in laser-driven ion acceleration under high relativistic intensity. Here, we report the experimental and numerical results on the laser-accelerated proton beams from such targets under moderate relativistic intensities I∼5×1019W/cm2. 40-TW femtosecond laser pulses were used to irradiate CNF-based double-layer targets. Compared to single-layer targets, significant enhancements on the cutoff energy and numbers of ions were observed. It was found that the CNF layer also leads to a larger divergence angle and a more homogeneous spatial distribution profile of the proton beam. Particle-in-cell simulations reveal the reason for the enhanced proton acceleration. It is found that the lateral electric field and the strong magnetic field built by the directly accelerated electrons from the CNF layer contribute to the enlarged divergence angle.

Collaborative mapping on sustainable development goals in Latin America UNESCO Global Geopark: A methodological discussion

UNESCO Global Geoparks (UGGps) are territories that promote sustainable development through a territorial management plan focusing on education, conservation, and local development. In their guidelines, they establish, among others, the relevance of the territorial bottom-up approach. This implies the active involvement and participation of the local communities on the projects and strategies focusing on sustainable territorial development and management. In this sense, the participatory processes should be one of the main strategies for the progress, analysis and diagnosis on the development and management of the UGGps. On this scope, the use of geographic analysis tools, like interpretative maps of the territory and the application of Geographic Information Systems (GIS) through a collaborative approach, could be an asset for the spatial planning required in the UGGps, reinforced by the local knowledge. One of the main applications that can be implemented in UGGps for the improvement, adaptation, and actualization of the spatial planning and management of the territories is the application of collaborative mapping strategies. This work is an example of a methodological proposal for the spatial diagnosis of the sustainable development in four UGGps of the Latin America and Caribbean Geoparks Network (GeoLAC) through a collaborative mapping process. This should be understood as a map's creation practice by local communities' perception. In addition, it also allows the understanding of the dynamics, evolution, and transformation of the UGGps through community knowledge and citizen science, supporting the improvement of the management plans of each territory. The objective of this methodology is to identify and discuss the spatial and territorial distribution of the “geopark” concept and how different activities related to geoconservation, geoeducation and geotourism, as main axes of the principles of the UGGp, are acting for and contributing to the sustainable development in four UGGps of the GeoLAC. Results allow to define new strategies to involve, in a more homogeneous spatial distribution, the impacts and benefits of the UGGps. The final maps become important tools not only for researchers or managers but also for local communities. This methodology has the potential to become a tool for its application in any UGGp willing to analyze the spatial distribution of the territorial strategies, the activities impact, and the benefits for the sustainable development of its territory. Furthermore, it can be an efficient evaluation tool when applied periodically in the territory, allowing to compare the development and evolution of the spatial impacts and territorial dynamics of the strategies defined by the management structure, calibrated by the vision and perception of the local communities.

Construction of vascularized tissue-engineered breast with dual angiogenic and adipogenic micro-tissues.

Hydrogel-based micro-tissue engineering technique, a bottom-up approach, is promising in constructing soft tissue of large size with homogeneous spatial distribution and superior regeneration capacity compared to the top-down approach. However, most of the studies employed micro-tissues with simple mesenchymal stem cells, which could hardly meet the growth of matrix and vessels. Therefore, we recommend a dual micro-tissues assembly strategy to construct vascularized tissue-engineered breast grafts (TEBGs). Adipose micro-tissues (AMs) and vessel micro-tissues (VMs) were fabricated by seeding adipose-derived stem cells (ADSCs) and human umbilical vein endothelial cells (HUVECs) on collagen microgels (COLs) with a uniform diameter of ∼250​μm, respectively. TEBGs were constructed by injecting the dual micro-tissues into 3D printed breast-like Thermoplastic Urethane (TPU) scaffolds, then implanted into the subcutaneous pockets on the back of nude mice. After 3 months of implantation, TEBGs based on dual micro-tissues performed larger volume of adipose tissue regeneration and neo-vessel formation compared to TEBGs based on single AMs. This study extends the application of micro-tissue engineering technique for the construction of soft grafts, and is expected to be useful for creating heterogeneous tissue constructs in the future.

Reaching Highly Uniform Perovskite Ink Flow from a Slot‐Die Head Toward Printed Solar Cells

Large‐scale manufacturing of perovskite solar cells (PSCs) requires the deposition of homogeneous and defect‐free perovskite films on large‐area substrates. Up to now, the knowledge developed for industrial slot‐die processing has not been fully transferred to the perovskite photovoltaic community. Here, the deposition of uniform perovskite layers by slot‐die coating (SDC). Computer fluid dynamics (CFD) simulations, experimental validation, and calculation of industrial uniformity parameters are demonstrated, which enabled to establish processing conditions for SDC of perovskite ink. This approach allowed for obtaining stable cross‐web flow in the slot‐die head resulting in the formation of a stable coating bead yielding uniform perovskite films. The best processing parameters are used for the fabrication of slot‐die‐coated PSCs, which showed a more homogeneous spatial distribution of photovoltaic parameters compared to their spin‐coated counterparts. Better reproducibility observed in device performance is a step forward toward the commercialization of perovskite photovoltaic technology. For the first time, the industrial approach used for the optimization of slot‐die coating is applied for the processing of perovskite inks that have special conditions such as low viscosity and in situ crystallization on the substrate.