Low Surface Research Articles

Numerical and experimental investigation on mixed convection heat transfer inside cavity heated from below with reciprocating moving upper surface

This investigation involves a numerical and experimental work on mixed convective heat transfer inside cavity heated from below and reciprocating moving upper surface. For the experimental work, the smoke method is used for the air flow visualization. The experiments include the measurements of air temperature inside the cavity and upper and lower surfaces of duct. For the numerical work, the velocity boundary condition of the upper surface is defined asu=umaxsinωt with low constant temperature (Tc), whereas the lower surface of duct is kept at constant wall temperature (Th) and the vertical walls are well insulted. The mathematical model adopted in the calculations are solved by building an own code using finite difference method in MATLAB software The influences of Richardson number (Ri), Aspect Ratio (AR) and dimensionless period (dp) on the flow behavior and average Nusselt number (Nu) are investigated. The experimental and numerical outcomes are compared under identical conditions, where the comparison gives a good matching between them. The numerical outcomes demonstrated that the rising in AR with constant Ri leads to increase the Nu values. For AR=1 and Ri=0.01, the average Nu increases with dp. The experimental results show that the Nu value increases to 3.2 with increasing AR to 2 under constant Ri=10. The dp decreases to 33 s when AR is increased under constant Ri value. The data indicated that Nu rises with reducing in Ri for all AR values. The value of Nu depends on dp, AR and Ri. The multi-cells flow is observed when Ri is raised under constant AR value. The maximum Nu value is obtained for low values of AR and Ri. The profiles of Nu reveal that AR, Ri and dp have considerable influences on the heat transfer.

Feasibility analysis and parameter optimization of ultrasonic assisted electrolytic plasma polishing of small modulus gears

Precision polishing of small modulus gears is a difficult task due to the complexity of their geometry. Electrolytic plasma polishing technology as a green and efficient processing method, it can effectively decrease the friction between parts and improve the service life. However, considering the uneven distribution of gas layers on the surface of workpieces in electrolytic plasma polishing, which affects the precision of workpiece shapes after polishing, this study proposed the use of ultrasonic vibrations to generate pressure waves to improve the fluid characteristics. Comparative experiments on small modulus gear electrolytic plasma polishing with and without ultrasonic vibration were conducted. A high-speed camera was utilized to monitor the distribution of gas layers around the workpiece during the polishing process in real-time. The optical measurement methods were used to evaluate the gear precision. The results indicate that ultrasonic assistance is beneficial in improving the uniformity of the gas layers surrounding the workpiece, achieving higher gear precision, and obtaining a lower surface roughness after polishing. Through orthogonal experiments, this study analyzed the effects of various process parameters on the surface roughness of gear profiles and the uniformity of material removal after polishing. These parameters included power voltage, polishing time, workpiece immersion depth, ultrasonic frequency, and workpiece posture angle. An optimal combination of process parameters was identified. The results show that the best surface roughness and gear precision were achieved with a power voltage of 300 V, a polishing time of 4 min, a workpiece immersion depth of about 10 mm, an ultrasonic frequency of 40 kHz, and a workpiece tilt angle of 45°.

Preparation and infrared shielding of polyaniline@MWCNTs flexible electrochromic device based on cotton fabric

Electrochromic fabric was formed by interfacial polymerization of polyaniline (PANI) and multi-walled carbon nanotubes (MWCNTs) on the surface of cotton cloth. The morphology and properties of the composite films were controlled by changing the content of multi-walled carbon nanotubes. The electrochromic properties of the fabric and its application in the field of near-infrared thermal shielding were studied. It is found that the electrochromic fabric with MWCNTs have better electrochemical and color-changing properties. Electrochromic fabrics achieve color changes from light yellow to yellow-green to dark green in the voltage range of -1.0 to 1.2V, and maintain a fast color switching time (2.15s for coloring, 1.89s for bleaching) after 600 cycles. The reflection contrast (ΔR) at 500nm is 23.01%. Moreover, the electrochromic devices are assembled with fabrics. The device has obvious discoloration and good bending stability. In addition, the thermal shielding is realized by using their reflection characteristics in the visual-near-infrared region. The results show that the electrochromic device has a low surface temperature at different environmental condition, and the thermal reduction from the original state to the bleached state is up to 3.8 ° C, indicating the potential application of the device in thermal regulation.

A Novel Approach to Fabricate Fe-based Thin Film Metallic Glass With Commercial Boron Carbide and AISI M42 Tool Steel

In this study, we report a Fe-based thin film metallic glass (Fe-Cr-Mo-C-B-X TFMG) fabricated by magnetron sputtering with commercial boron carbide (B4C) target and AISI M42 tool steel pellets. Varied number of M42 pellets were co-sputtered with B4C target, resulting in Fe content ranged from 48.1 at% to 62.8 at%. X-ray diffraction and transmission electron microscopy confirmed that all sample films were amorphous. All samples showed glass transition and crystallization in differential scanning calorimetry (DSC), similar to typical metallic glasses. However, glass transition was barely observable in B4m owing to its high oxygen content. The sample films also had extremely low surface roughness of 0.14 – 0.26 nm. The sample films also showed tribological properties comparable to conventionally deposited TFMG, where the highest hardness and reduced modulus obtained was 9.0 GPa and 150.8 GPa respectively. The sample films also demonstrated specific wear rate K0 as low as 1.6 × 10-5 mm3Nm-1. Our work demonstrates a more cost-effective and sustainable way of fabricating Fe-based TFMG, in which both AISI M42 are readily available and can be easily recycled after use.

Eco-friendly covalently connected silicone hydrogel with negatively charged surface for marine anti-biofouling

In this study, a silicone hydrogel (Gel-TA-Si-x) with amphiphilic and negatively charged surfaces was prepared by combining low surface free energy silicone with highly hydrophilic hydrogel materials using the method of one-step solvent-free bulk polymerization. The hydrogel films exhibited good mechanical properties. This was primarily reflected in the high tensile strength (1 MPa) and elongation at break (358.1 %). Notably, the film exhibited increased hydrophobicity, higher water contact angle and gradual decline in water absorption rate as the mPDMS monomer dosage increased. Despite this, the surface free energy remained low at 22.1 mJ m−2, indicating effective fouling release capability (removal strength against pseudobarnacles was 0.16 MPa). In addition, the surface zeta potential of the hydrogel was as low as −86 mV (at pH = 10). Laboratory antifouling performance tests indicated that the surface negativity of the material enhanced its static antifouling performance and the hydrogel with a negatively charged surface exhibited high bacterial adhesion resistance of 93 % and good resistance to Chlorella adherence and biofilm inhibition. Favorable anti-fouling performance was observed after 180 d of marine field testing. Moreover, the covalent connection of silicone monomers with hydrogel monomers through copolymerization create a stable three-dimension crosslinking network, thereby improving the durability of materials in complex marine environments. This study provides a new idea for developing efficient and environmentally friendly silicone hydrogel antifouling materials.

Charge pumping triboelectric nanogenerator with dust clearance and elastic support for wind energy harvesting

Triboelectric nanogenerator (TENG) as an energy harvester faces the challenges of low surface charge density, dust generation in friction and soft contact within dielectrics. Accordingly, a charge pumping triboelectric nanogenerator with a tubular-plate coupled structure is proposed to address the above challenges and is used to harvest wind energy. It mainly consists of a top tubular TENG and a bottom plate TENG, synchronously driven by an unidirectionally open-closed fan blade through a shared shaft. The unidirectionally open-closed fan blades produce an eccentric torque with the different open-closed states, which is used as the impetus for the unidirectional rotation of the fan structure and the rotor of TENG. Charge pumping technology is applied in top TENG to enhance surface charge density and outputting electricity in way of noncontact electrostatic induction. The COMSOL software is applied to obtain the distribution of electric field and potential during the relative motion of two tubular electrodes. Lint blades and steel sheets are utilized in bottom TENG for the dust clearance and the elastic support, respectively. Consequently, the voltage is increased by 15.5 times and the current about 3.0 times with the charge pumping strategy. The dust clearance and elastic support can improve the output current. The total output voltage is up to 2.8kV and the current is 103.0 μA at 200rpm, generating a peak power of 184.9mW and an average power of 6.4mW. A buck circuit is used in the output circuit to lower and stabilize the output voltage for the electronics. The output electricity can support the work of a thermo-hygrometer, two linear lamps (10W), two circular LED lamps (18W), and light 417 big LEDs with a diameter of 10mm, serving as a continuous energy source in wilds.

Influence of Sowing Media and Variety on Physiological Performance and Yield of Early Cauliflower (Brassica oleracea L. var. botrytis) and Correlation Study with Yield

An experiment was conducted during 2018 and 2019 at the Experimental Farm, Department of Horticulture, College of Agriculture, Assam Agricultural University, Jorhat and at Farmer’s field to assess the physiological performance of early cauliflower varieties in different sowing media and to evaluate their performance in the field as well as to study the correlation of different physiological parameters with curd yield. The experiment was laid out in Randomized Block Design with eight treatments comprising of four sowing media [M1-cocopeat (60): vermiculite (20): perlite (20), M2-cocopeat (50): vermicompost (50),M3-cocopeat (50): vermicompost (50): microbial consortium @1:100 and M4-Conventional nursery]and two varieties [V1 (White Diamond) and V2 (CFL1522)] replicated thrice. The results revealed that growing medium had significant influence on different physiological parameters of early cauliflower seedling. Maximum chlorophyll content was recorded in M3 (0.98 mg g-1fw), maximum number of stomata in upper and lower surface (83.47and 150.97), relative water content (90.06 %) and dry matter accumulation (11.41 %) were recorded in M2. Between the two varieties, V1 recorded higher stomata number (145.06) in the lower surface. In the main field, the plants grown from M3 showcased superior performance with highest relative water content (93.62%), chlorophyll content at 30 days after transplanting (1.40 mg g-1fw) and at harvest (2.16 mg g-1fw), membrane stability index (65.32%), minimum lipid peroxidation (0.85 n mol g-1fw) at harvest and maximum curd yield (200.22 q/ha). Between the two varieties White Diamond(V1) recorded the higher relative water content (89.48 %) while V2 (CFL 1522) recorded the maximum membrane stability index (55.10%) and non-significant influence of variety was noticed on yield. Correlation coefficient analysis indicated chlorophyll content at seedling stage, crop growth and at harvest stage, relative leaf water content and membrane stability index at harvest have positive and significant correlation with curd yield of cauliflower. The study indicates sowing media had significant influence on physiological parameters of seedlings of early cauliflower which is again reflected in the field condition influencing yield as well and can be concluded that sowing media cocopeat (50): vermicompost (50): microbial consortium @1:100 can be used for nursery raising of early cauliflower seedling in Assam condition.

Analysis of Fracturing Above Block Caving Back: A Spherical Shell Theory Approach and BEM Numerical Simulation

ABSTRACTExperiments and field monitoring have revealed that in block caving, fractures over the cave crown tend to form in narrow curved bands that are parallel or subparallel to the cave back surface. These fractures delineate curved shells of orebody between the bands and the cave back. The effectiveness of block caving hinges on the subsequent fracturing and fragmentation of these orebody shells. This study adopts a dual approach, combining thin spherical shell theory and full 3D numerical simulations along with principles of linear elastic fracture mechanics, to investigate the fracturing behaviour of these shells. Analytical analysis indicates that under axisymmetric loading, latitudinal tensile fractures predominantly initiate across the most part of the shell, occurring on both the upper and lower surfaces, except at a localised area. Additionally, longitudinal tensile fractures may initiate at the central area of the upper surface, while shear fractures tend to occur around the edge of the shell. Consequently, the shells become susceptible to fracturing, leading to the collapse or cave‐in of the orebody. Numerical simulations agree with these findings, illustrating that fracturing points within the shell region are longitudinally dispersed throughout the entire shell. Most of these fracturing points satisfy the criteria for tensile fracturing, particularly within the middle portion of the shell, aligning with the analytical results. Furthermore, simulations considering nonaxisymmetric loading patterns demonstrate that regions surrounding the caving cavity, aligned with the minimum principal in situ stress, exhibit heightened susceptibility to fracture initiation. This insight holds potential significance for optimising the design of the caving process.

Multi-objective optimization in EDM of functionally graded Fe-Al using grey relational analysis

Abstract Functionally Graded Materials (FGMs) are multipurpose materials with a specific goal of managing changes in structural, thermal, or functional qualities. They feature a spatial variation in microstructure and/or composition. The current work prepared three layers of sample with different chemical compositions of Fe-Al FGM (50 Al-50 Fe, 45 Al-55 Fe, and 40 Al-60 Fe) at. % produced by powder metallurgy, then studied the machining behavior of these samples. The literature on the machining behavior of FGM was reviewed, and the influence of electrical discharge machine (EDM) process parameters such as voltage (V), current (I), pulse-on time, and pulse-off time on performance characteristics (material removal rate (MRR), tool wear rate (TWR), and surface roughness (Ra)) was investigated. The optimal machining settings for Fe-Al FGM samples will be ascertained by use of Grey Relational Analysis (GRA), which is based on the Taguchi approach, after an experimental investigation of the L18 orthogonal array design of trials. The GRA findings verify that V 140 volts, Ip10 A, Ton 100 μs, and Toff 75 μs is the optimal combination of process parameters. It has been found that the voltage is more significantly affected than the rest of the input parameters to obtain greater material removal rate (MRR) and lower tool wear rate (EWR) and surface roughness (Ra) through the response table. According to the study, choosing the right process parameters can improve the multi-performance feature.

Transfunctional Optical Thin Films via Bioinspired Engineering.

Advanced multifunctional optical films or substrates have continued to develop as essential components in the diverse optical industry. Several functions, including high transparency, self-cleaning ability, structural color, flexibility, and durability, are required to obtain versatile and practical optical films. Herein, we introduce a cicada-wing-inspired transfunctional optical thin film (CITOTF) with nanostructures on both surface nanostructures inspired by the cicada-wings. CITOTFs made of perfluoropolyether (PFPE), which has a low refractive index, low surface energy, and high robustness as a substrate material, are obtained by a well-designed sandwich lithography method. We fabricated two types of CITOTFs depending on the size (300 and 1000 nm) of the surface nanostructure. 300-CITOTF and 1000-CITOTF exhibit high transparency and structural color effects, respectively. Both samples demonstrate self-cleaning ability, flexibility, and long-term stability. The bioinspired transfunctional optical films developed in this study can be used in various optical applications.

Controlling spheroid attachment improves pancreatic beta cell differentiation from human iPS cells.

Regenerative medicine using human induced pluripotent stem cells (hiPSCs) is available for treating type 1 diabetes; however, the efficiency and maturation of hiPSC differentiation into pancreatic beta cells requires improvement. Various protocols, including three-dimensional (3D) culture, have been developed to improve differentiation efficiency and maturation. Several methods for 3D culture have been reported; however, they require costly and complicated equipment, special materials, and complicated operations. To solve these problems, we developed a simple 3D culture method under static conditions using a cyclo-olefin polymer (COP) characterized by high moisture barrier properties, low surface energy, and hydrophobicity. Using this 3D method and our simple and low-cost protocol, we found that differentiation into the definitive endoderm (DE) was better when the spheroids were attached. Therefore, upon the addition of Y-27632, attached spheroids with unique shapes and cavities were formed, and the differentiation efficiency into DE increased. During DE differentiation, the attachment of spheroids to the substrate and their subsequent floating improved differentiation efficiency. We found that the amount of C-peptide in spheroids differentiated using COP dishes was greater than that in rotary culture. Furthermore, INSULIN was highly expressed in areas with low cell density, suggesting that the unique shape of the spheroids made from COP dishes improved differentiation efficiency. Our study suggests that a device-free, simple 3D culture method that controls spheroid attachment improves the efficiency of hiPSC differentiation into pancreatic beta cells.

Cooperative Use of N-Heterocyclic Carbenes and Thiols on a Silver Surface: A Synergetic Approach to Surface Modification.

Surface modification through the formation of a self-assembled monolayer (SAM) can effectively engineer the physicochemical properties of the surface/material. However, the precise design of multifunctional SAMs at the molecular level is still a major challenge. Here, we jointly use N-heterocyclic carbenes (NHCs) and thiols to form multifunctional hetero-SAM systems that demonstrate excellent chemical stability, electrical conductivity, and, in silico, catalytic activity. This synergistic effect is facilitated by the high surface mobility and electron-rich nature of NHCs, combined with the strong binding strength of thiols. Scanning tunneling microscopy, electrical conductivity, and scanning electron microscope measurements, as well as density functional theory calculations, were employed to explore the synergistic interactions in the supramolecular SAMs. The van der Waals integration of ballbot-type NHCs and thiols enables the SAMs to exhibit both superior surface anticorrosion properties (attributing to the shift in the d-band center) and low surface resistance originating from the band alignment. Moreover, we find that the deposition sequence of flat-lying NHCs and thiols results in SAMs with different configurations, which can further tune the mechanistic pathway in silico in the acetylene hydrogenation process. Our results provide essential molecular insights into the local electronic control of the new SAM/metal interface and the high stability of the emergent multifunctionality (NHC/thiol)-SAMs forming self-assembled lamellae structures in the nanometer regime.

Isotropic ↔ anisotropic surface geometry transitions induced by adsorbed surfactants at water/vapor interfaces.

Adsorbates at a water/vapor interface change the surface geometry through altered surface tension, yet detailed theoretical studies are relatively sparse, and many applications focus on ensemble average characteristics. Here, we demonstrate that different interpretations of surface geometry emerge when considering the distributions of surface curvature and orientation as a function of adsorbed surfactant concentration and sterics. At low surface densities, the tributyl phosphate (TBP) sorbed water/vapor surface has an increased presence of ridges that are defined by principal curvatures κ1 and κ2 of opposite signs yet close in magnitude. As the TBP surface density increases, the difference in principal curvatures slowly increases. There is a distinct transition of the surface geometry, where the ridge-like features become much more pronounced, having sides whose orientation is normal to a flat interfacial plane. Thus, as the TBP surfactant is added to the surface, the surface curvatures become anisotropic in terms of the difference in magnitude of κ1 and κ2. We label this an isotropic → anisotropic geometric transition. Comparing the surface geometry as a function of the carbon tail length of the alkyl phosphate surfactant reveals that smaller surfactants also anisotropically enhance surface curvatures and that adsorbed alkyl tails to the surface stabilize and increase the symmetry of surface waves along the two principal curvature axes. We label this an anisotropic → isotropic geometric transition. These results reflect the opportunity to incorporate more realistic distributions of surface geometry within the collective understanding of statistical theories of surfaces, including capillary wave theory.

Construction of Iron-Modified Lignin-Based Nanomicrocapsules for Enhancing the Functionality of Natural Product-Based Pesticides.

To address the issue of low pesticide utilization owing to poor dispersibility, low leaf surface adhesion, and poor transport within plants, this study exploits electrostatic interactions between sodium lignosulfonate (SL) and dodecyltrimethylammonium chloride (DTAC) to induce self-assembly, followed by iron ion (Fe3+) chelation and loading with a natural product-based pesticide, rosin-based triazole derivative (RTD), yielding RTD@SL-DTAC-Fe nanomicrocapsules (NMs). It is worth noting that the presence of Fe3+ enhances the dispersibility of the NMs. The water dispersibility and photostability of RTD are significantly improved after encapsulation, and a stimulus response to laccase is achieved. Leaf-washing experiments confirm the enhanced adhesion of RTD@SL-DTAC-Fe NMs to the surface of rice plant leaves compared to that of free RTD. Fluorescently labeled NMs exhibit bidirectional transport within rice plants, and RTD@SL-DTAC-Fe NMs demonstrates better transport performance than RTD. In vitro and in vivo antifungal tests indicate that encapsulation by NMs significantly enhanced pesticide activity. Field trials demonstrate that NMs exhibited prolonged efficacy compared to RTD. Finally, the safety evaluation confirms the environmental friendliness of the NMs. This study provides valuable insight for optimizing and improving the utilization efficiency and biosafety of natural product-based pesticides.

Membrane piezoelectric MDS-actuator with a flat double spiral of interacting electrodes

A schematic diagram and mathematical model of functioning of a new piezoelectric membrane (MDS) actuator with double spiral (DS) electrodes on the upper and/or lower surfaces of a thin piezoelectric layer with axisymmetric and periodic (with a small period) in radial coordinate mutual reversed electric polarization are presented. The polarization of the layer was realized as a result of connecting the polarizing electric voltage of the appropriate value to the outputs of the double spirals of the electrodes. The electrodes of each (upper and lower) double spiral of the MDS-actuator are made in the form of electrodeposited ribbon coatings on the surfaces of the piezoelectric layer in close proximity to each other (due to the small spiral pitch) to create high values of electric field strength along the lines of force in localized areas of the piezoelectric layer between them when an alternating or constant control electric voltage is connected to the electrodes, in particular, with positive and negative values of the electrical potentials. Importantly, the electric field force lines and, as a consequence, the polarization of the piezoelectric layer of the MDS actuator are oriented mainly along (i.e. towards or against) the radial coordinate of the membrane, in contrast to many conventional actuator schemes. The results of numerical modeling for a circular elastic membrane with piezoelectric actuators installed on its upper and lower surfaces confirmed the effectiveness of the proposed piezoelectric MDS-actuator when it functions according to the “bimorph” scheme, including the use of the proposed new structural element (section) – a piezoelectric “compression ring” MDS at various geometric and control parameters. The effect of a significant increase in the membrane deflection with installed piezoelectric MDS-actuators compared to the use of traditional homogeneous plate piezoelectric actuators of bimorph type for different conditions of the membrane fixation, in particular, stationary (rigid) fixation of its center is revealed. For a hybrid piezoelectric MDS-actuator including independent concentric round and circular (i.e. “compression ring”) sections, the non-monotonic nature and numerical analysis of the nonlinear dependence of the largest deflection at the center of a hinge-immobile membrane fixed at the edge on the ratio of the radii of its round and circular MDS sections were revealed. The cases in which the effect of the “compression ring” is manifested, i.e. when the maximum deflection of a membrane with the “compression ring” exceeds the best possible value of the deflection of this membrane without its use in the traditional “bimorph” scheme, are identified. The new piezoelectric MDS-actuator can be used in micromechanics, controlled optics, sensor technology, acoustics, in particular, in the manufacture of piezoelectric acoustic or sensor elements of membrane type, electromechanical transducers for vibration energy collection.

Highly Active Oxygen Evolution Reaction of NiMoO4 Sub-1nm Nanowires Boosts Luminol Electrochemiluminescence.

In recent years, there has been an increasing research focus on the luminol-H2O electrochemiluminescence (ECL) system due to its ability to address the instability and toxicity of H2O2, which are common issues associated with the conventional luminol-H2O2 ECL system. To enhance the ECL efficiency of the luminol-H2O system, researchers have developed electrocatalytic materials with exceptional oxygen evolution reaction (OER) properties to facilitate water electrolysis into O2 to produce reactive oxygen species (ROS) and act as co-reactant promoters. However, most of these materials are characterized by their nanoscale or microscale dimensions, resulting in relatively large sizes and low specific surface areas, which hinder the application of the luminol-H2O system. To address this challenge, nickel molybdate sub-1nm nanowires (NiMoO4 S1 NWs) with a large specific surface area is synthesized that can offer many active sites to enhance the performance of the OER to boost the ECL of luminol. This study demonstrates that the large amount of ROS generated by the OER of NiMoO4 S1 NWs play a crucial role in enhancing the ECL intensity of luminol. Finally, a NiMoO4 S1 NWs-based ECL biosensor for the highly sensitive detection of the nucleocapsid proteins of SARS-CoV-2 is successfully constructed.

Biocompatibility and antibacterial properties of medical stainless steel and titanium modified by alumina and hafnia films prepared by atomic layer deposition.

New methods for producing surfaces with suitable biocompatible properties are desirable due to increasing demands for biomedical devices. Stainless steel 316 L and cp- titanium specimens were coated with thin films of alumina and hafnia deposited using the atomic layer deposition method at two temperatures, 180 and 260 °C. The morphology of the films was analysed using scanning electron microscopy, and their surface energies were determined based on drop contact angle measurements. Biocompatibility assays performed using mesenchymal stem cells were evaluated by incubating the specimens and then exposing their extracts to the cells or directly seeding cells on the specimen surfaces. No detrimental effect was noticed for any of the specimens. Antibacterial properties were tested by directly incubating the specimens with the bacteria Staphylococcus aureus. Overall, our data show that all prepared films were biocompatible. Alumina films deposited on cp-titanium at 260 °C outperform the other prepared and tested surfaces regarding antiadhesive properties, which could be related to their low surface energy.

IMMU-70. GLIOBLASTOMA DERIVED IL-8 INSTRUCTS IMMUNE CELL IDENTITY IN LATERAL VENTRICLE CONTACTING TUMORS

Abstract Adult IDH-wildtype glioblastoma (GBM) is an aggressive brain tumor with no established immunotherapy. Glioblastoma tumors that contact the ventricular-subventricular zone (V-SVZ) stem cell niche have especially poor clinical outcomes (PMC5771712, PMC5262526) and abnormal immune microenvironments filled with CD32+ HLA-DRhi macrophages that have displaced resident microglia (PMC10371245). Identifying the origin and role of these CD32+ macrophages is likely critical to developing successful GBM immunotherapies. Here, we present a mechanistic origin for these CD32+ cells as M_IL-8 macrophages. In ex vivo experiments with conditioned medium from primary human tumor cells, IL-8 was sufficient and necessary for tumor cells to instruct healthy macrophages, and inhibitory antibodies to IL-8 blocked the generation of CD32+ CD163+ M_IL-8 cells. Additionally, IL-8 protein was present in GBM tumor cells in vivo and especially common in tumors contacting the V-SVZ (p<0.0001, N=192 cores from 73 patients). Surface proteins CXCR1 and CXCR2, the primary receptors for IL-8, were detected on cells that were spatially separated from IL-8+ glioblastoma cells in tumors contacting the V-SVZ. These results suggest the hypothesis that glioblastoma-cell IL-8 instructs incoming CXCR1+ hematopoietic macrophages to adopt a suppressive M_IL-8 identity in V-SVZ-contacting GBM. Abundant HLA-DR (MHC II) observed on the CD32+ M_IL-8 cells closely matched the signature phenotype of cells in human tumors (PMC10371245) and contrasted with lower surface MHC II expression typically observed on human myeloid derived suppressor cells (PMC6608074). M_IL-8 cells might especially target CD4+ helper T cells required for effective cancer immunotherapy (PMC5312823). IL-8 and CD32+ macrophages should now be explored as targets in combination with GBM immunotherapies, especially for patients whose tumors present with radiographic contact with the V-SVZ stem cell niche. Some results here have been shared in a bioRxiv preprint by the these authors (PMC10996638).

Thermohydraulic Performance and Flow Structures of Diamond Pyramid Arrays

Abstract Surface features are a common heat transfer enhancement method used in a myriad of applications including gas turbines and heat exchangers. One such style of surface features are diamond pyramids, which offer significant heat transfer augmentation for moderate increases in overall pressure losses. This study investigated a suite of additively manufactured pyramids in a variety of sizes and arrangements at relevant scale contained in test coupons. Designs were printed with low surface roughness relative to typical additive components (Ra < 5µm), and pyramids were printed within 100 µm of the design intent. Experimental and computational results indicate that the pressure penalty and heat transfer increased as the pyramids increased in size with aligned pyramids on both channel walls having higher values than staggered pyramids. It was found that implementing the pyramids onto a rough surface had a lesser impact on the friction factor than implementing on a smooth surface, but that the relative increase in heat transfer was the same regardless of the roughness of the endwall. The greatest enhancement to local heat transfer and pressure loss was offset from the location of minimum flow area due to local acceleration around the wake regions. The vortices formed in the wake of the pyramid structures enhanced the endwall heat transfer and shear stress. The performance of the pyramids investigated in this study follows a similar trend to prior studies investigating smooth rib geometries, though certain rib designs had higher heat transfer at lower pressure losses.

Long-Term Clinical and Radiographic Outcomes of Hydrophilic Implants: A 10-Year Study in a Specialist Private Practice.

To report the 10-year clinical and radiographic outcomes of implants placed in grafted (GBR) and non-grafted (no-GBR) sites in a Swiss specialist private practice using hydrophilic implants with a low surface roughness flange. Fifty consecutively enrolled patients received 159 hydrophilic implants with a low surface roughness flange. A first re-evaluation was performed 1 year after delivery of restoration (T1). An additional examination was performed at the 10-year follow-up (T2) including the assessment of clinical (i.e., periodontal/peri-implant pockets probing depths (PPD) (mm), full-mouth bleeding score (%), implant survival rate, mid-buccal keratinized mucosa (KM) width in mm, and peri-implant phenotype), and radiographic (i.e., marginal bone level change [ΔMBL]) outcomes. Biological, mechanical and technical complications were also recorded. Out of the initial cohort, 22 patients (9/40.9% male and 13/59% female) and 63 implants (47 with GBR, 16 without GBR), could be re-examined at T2. Overall, ΔMBL (T2-T1) was -0.56 ± 0.96 mm. In the GBR group, ΔMBL were significantly higher at the distal sites compared to the no-GBR group (-0.75 ± 1.17 mm vs. -0.12 ± 1.29 mm, p = 0.045), however, in the GBR group MBL started at a higher level at T1 but were similar with the no-GBR group at T2. Implant survival was 100% with only very few technical complications (6.3%). Mean PPD amounted to 3.84 ± 1.00 mm with significantly higher values in the GBR group (3.98 ± 1.08 mm vs. 3.45 ± 0.60 mm; p = 0.016). Nineteen implants (30.1%) were diagnosed with peri-implant health while 44 (69.9%) presented with peri-implant mucositis. Within the limitations of this study, favorable clinical and radiographic conditions were recorded around hydrophilic implants with a low surface roughness flange placed in pristine and augmented bone after 10 years in function.