Low Density Research Articles

Effect of crowding stress on liver health, gut permeability and gut microbiota of genetically improved farmed tilapia (GIFT, Oreochromis niloticus)

This study investigated the effects of crowding stress on liver and gut health in genetically improved farmed tilapia (GIFT, Oreochromis niloticus). Fish averaging 18.90 ± 0.01 g were reared at low (LD, 5 g/L) or high densities (HD, 100 g/L) for 14 days. The analysis revealed that the HD group significantly increased serum cortisol, glucose and adrenocorticotropic hormone (ACTH) levels in GIFT (P < 0.05). Serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were elevated in the HD group (P < 0.05). TUNEL staining of liver tissues revealed that the fluorescence intensity indicating apoptosis was significantly higher in the HD group (P < 0.05). Additionally, the HD group exhibited increased expression of p53 and Caspase3 in the liver (P < 0.05). In comparison to the LD group, the HD group showed a significant increase in gut superoxide dismutase (SOD) and catalase (CAT) activities, as well as malondialdehyde (MDA) content (P < 0.05). The expressions of inflammatory-related genes (tnfα, il-1β, il-8, and il-6) and pro-apoptotic genes (p53 and Caspase7) were significantly upregulated in the gut of the HD group (P < 0.05). Serum contents of D-lactate and diamine oxidase (DAO) were significantly elevated in HD group as comparison to LD group (P < 0.05), and significantly higher serum FITC-CM-dextran was observed in HD group versus LD group following oral gavage (P < 0.05). Furthermore, the HD group down-regulated the expressions of gut tight junction proteins (tjp2a, hif-1a, and zo-1) (P < 0.05), and significantly up-regulated the protein expression of phosphorylated myosin light chain 2 (P-MLC2) (P < 0.05). The 16S rDNA gene sequencing results indicated that the relative abundance of Cetobacterium was significantly lower (P < 0.05), and Enterovibrio and Weissella were significantly higher in the HD group (P < 0.05). Overall, crowding stress negatively affects GIFT liver and gut health, which is caused by inducing hepatic and intestinal apoptosis, impairing intestinal barrier function, and disrupting the gut microbiota.

Tunnel silicon nitride manipulated reconfigurable bi-mode nociceptor analog

Neuromorphic applications have shown great promise not only for efficient parallel computing mode to hold certain computational tasks, such as perception and recognition, but also as key biomimetic elements for the intelligent sensory system of next-generation robotics. However, achieving such a biomimetic nociceptor that can adaptively switch operation mode with a stimulation threshold remains a challenge. Through rational design of material properties and device structures, we realized an easily-fabricated, low-energy, and reconfigurable nociceptor. It is capable of threshold-triggered adaptive bi-mode jump that resembles the biological alarm system. With a tunnel silicon nitride (Si3N4) we mimicked the intensity- and rehearsal-triggered jump by means of the tunneling mode transition of Si3N4 dielectric. Under threshold signals the device can also express some common synaptic functions with an extremely low energy density of 33.5 fJ/μm2. In addition, through the modulation of Si3N4 thickness it is relatively easy to fabricate the device with differing pain degree. Our nociceptor analog based on a tunneling layer provides an opportunity for the analog pain alarm system and opens up a new path toward threshold-related novel applications.

In-situ electrochemical interface of Cu@Ag/C towards the ethylene electrosynthesis with adequate *CO supply

The conversion of carbon dioxide to ethylene by electrochemical reduction (CO2RR) provides a new strategy for achieving carbon dioxide conversion. However, copper-based catalysts have the disadvantages of unsatisfactory selectivity and low current density, which limit the potential CO2RR industrial expansion. Researches have verified that the real reaction sites at the catalyst surface often undergo reconstruction during the reaction, therefore, understanding and utilizing this phenomenon is crucial for improving catalytic performance. In this work, we introduced additional Ag component into Cu@Ag/C tandem catalyst by in-situ electrochemical reconstruction of Cu2CO3(OH)2/AgCl/C precursor. This electro-reduced catalyst exhibits a C2H4 Faradaic efficiency of 50.41% in H-cell, and 58.03% in the flow cell, surpassing the counterparts of pure Cu and Ag, as well as the Cu-Ag homolog with separated interface. Moreover, it also provides a long-term stability of 21 h with the ethylene Faraday efficiency (FE) over 50%. The appropriate amount of Ag dopant into the Cu catalyst changes the electronic structure of Cu surface by the electron transfer from Cu to Ag, which distinctly enhances the binding energy of CO2 on the catalyst. Meanwhile, in-situ Raman results and theoretical calculation reveal that the introduction of silver increases the number of active sites and improves the coverage of *CO intermediate, thereby accelerating the kinetics of C–C coupling and reducing its energy barrier. The combination of cascade catalytic strategy and in-situ electroreduction interface provides potential applications for future artificial carbon balance.

Characterization and gene expression profiles of Cilus gilberti leptin in response to culture parameters

The Chilean meagre, Cilus gilberti, emerges as a novel species to South American aquaculture. Nevertheless, the successful establishment of its cultivation necessitates careful consideration of productive parameters and tolerance to abiotic stressors. To address these challenges, the identifications of biomarkers emerges as a promising approach. Indeed, leptin stands out as a potential biomarker, given its multifaceted role. This study focuses on characterizing leptin in C. gilberti (cgLep) and assessing its gene expression in juveniles exposed to different culture and feeding conditions. The results indicated that cgLep coding sequence yields a 137-amino acid prohormone, preserving high relevant cysteine residues for maintaining its structural integrity. Basal cgLep gene expression profiles reveal its expression mainly in the liver, followed by white muscle. Conversely, its receptor (cgLepR) exhibits higher levels in white muscle. Additionally, it was observed that juveniles in a postprandial state exhibited an upregulation of hepatic cgLep. Simultaneously, the cgLepR showed a significant increase at brain level during the preprandial stage. The exposure to acute hypoxia revealed a notable upregulation of cgLep after two hours of low oxygen availability and returned to normoxia baseline after six hours post-hypoxia. Notably, when subjected to a prolonged daily hypoxia regimen, no significant differences in leptin mRNA expression were observed. This suggests a dynamic adaptive response of the C. gilberti leptin system to hypoxia. Finally, juvenile Chilean meagre cultivated at 15 Kg/m3 showcase significant individual variability in hepatic leptin expression levels when compared to those cultured at 25 or 35 kg/m3. These observations highlight that leptin primarily expresses in the liver and its expression is notably influenced by fasting periods and chronic stress induced by low stock density. This variability in leptin expression could potentially impact food intake, emphasizing the importance of considering these factors in the design and implementation of aquaculture practices for Chilean meagre.

Needs and Challenges for Volunteering in Rural Areas: Lessons Learned From a Survey of a Service Organization in Rural Michigan.

Volunteers are the foundation of social service agencies in rural communities, yet limited research exists on their needs and challenges. Motivated by the multidimensional older voluntarism sustainability framework, this study aims to understand (1) the characteristics of volunteers, (2) the relationships between volunteers' sense of community and their own aging and volunteer retention, and (3) the unique challenges faced by volunteers and volunteer-based agencies. This study uses a mixed-methods design. Data were gathered via telephone interviews (n = 76) and in-person focus groups (n = 14) from the volunteer pool of a nonprofit organization in rural Michigan. Descriptive and regression analyses were conducted to understand the characteristics of the volunteers. Thematic analysis was conducted to identify unique challenges faced by rural agencies and volunteers. Findings show that most volunteers were over 70, women, married, volunteered weekly or more, and were affiliated with multiple agencies. Volunteers with a stronger attachment to the community and higher self-perceptions of aging were likelier to continue and increase volunteering commitments. Due to the low population density in rural areas, volunteers were concerned about the heavy burden of volunteering, the lack of social connections with fellow volunteers, and the lack of active involvement in shaping the organization. Results from the study shed light on the urgent need for creative and engaging volunteer recruitment and retention strategies to sustain older adults, service agencies, and communities in rural areas.

Design and performance optimization of a novel CAES system integrated with coaxial casing geothermal utilization

At present, the heat storage sub-system in the adiabatic compressed air energy storage system generally has low heat storage density and limited heat storage temperature, resulting in mediocre power generation efficiency of the system. To address these issues, this paper proposes a novel approach for coupling the energy storage system with geothermal energy utilization. This study innovatively uses coaxial casing wells to extract geothermal energy and to preheat compressed air in front of the expander. Detailed numerical investigations and dynamic thermodynamic analysis are carried out to evaluate system performance. Sensitivity and optimization are analyzed to identify the operational and design parameters of the proposed system. In addition, an economic analysis is conducted to estimate the investment and payback of the energy storage system. The results show that geothermal energy utilization can directly and significantly enhance the electric, heating and cooling energy output of compressed air energy storage system. During one 24-hours operation cycle, the electricity output is 104.45GJ, the heating supply output is 81.59 GJ, and the cooling supply output is 16.69 GJ. The RTE and energy efficiency are 64.26 % and 122.68 %, respectively. Economic analysis shows that the static payback period is 12.17 years, and the net present value can reach 3.46 million USD. It can be concluded that geothermal energy plays a greater role in energy storage systems than geothermal power production alone. The compressed air energy storage system combined with geothermal energy addresses current issues and leads to improved system performance.

Fabrication of Ni–ZrO2 nanocomposites through a new electroforming bath and Assessment of their morphology, wear, and corrosion resistance

Nowadays, researchers are looking for ways to produce complex tools and pieces with high precision at a low cost. In recent decades, electroforming has been an important and stable technique for producing composite parts. In this research, Ni–ZrO2 nanocomposite foils were fabricated by using a nickel-chloride bath through electroforming, a bath not previously utilized for this purpose. In this study, the effects of ZrO2 concentration and direct current density on the volume percentage of ZrO2 nanoparticles and the grain size of the nickel matrix of foils are also investigated. The sample with 13.65 vol % nanoparticles had the highest volume percentage and the minimum nickel grain size of 516.9 nm, which is almost 46 % smaller than the grain size of pure nickel foil. The wear and corrosion behavior of the foils were examined using a pin-on-disk wear test, potentiodynamic polarization, and impedance spectroscopy analysis. The results showed considerable improvement in the wear and corrosion resistance of the Ni–ZrO2 samples compared to the pure electroformed nickel. The nanocomposites exhibit a lower friction coefficient than pure nickel, with a maximum reduction of 44 %. A composite specimen of Ni–ZrO2 had 2.5 % lower corrosion density and 596 % higher charge transfer resistance compared to pure nickel. It was concluded that the nickel-chloride bath has an excellent potential to produce composite nickel foils with acceptable brightness, satisfactory wear, and corrosion resistance.

Extracellular matrix regulation of cell spheroid invasion in a 3D bioprinted solid tumor-on-a-chip

Tumor organoids and tumors-on-chips can be built by placing patient-derived cells within an extracellular matrix (ECM) for personalized medicine. The ECM influences the tumor response, and understanding the ECM-tumor relationship is important before translating tumor-on-chips into clinics. In this work, we tuned the physical and structural characteristics of ECM in a bioprinted soft-tissue sarcoma microtissue. We formed 3D spheroids at a controlled size and encapsulated them into our gelatin methacryloyl (GelMA)-based bioink to make perfusable hydrogel-based microfluidic chips. We then demonstrated the scalability and customization flexibility of our hydrogel-based chip via engineering tools. A multiscale physical and structural data analysis suggested a relationship between cell invasion response and bioink characteristics. Tumor cell invasive behavior and focal adhesion properties were observed in response to varying polymer network densities of the GelMA-based bioink. Immunostaining assays and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) helped assess the bioactivity of the microtissue and measure the cell invasion. The RT-qPCR results showed higher expressions of HIF-1α, CD44, and MMP2 genes in a lower polymer density, highlighting the correlation between bioink structural porosity, ECM stiffness, and tumor spheroid response. In conclusion, this work is the first step in modeling STS tumor invasiveness in hydrogel-based microfluidic chips, and our tunable bioink may help reduce the variability of current tumor-on-chips. Statement of SignificanceWe optimized an engineering protocol for making tumor spheroids at a controlled size, embedding spheroids into a gelatin-based matrix, and constructing a perfusable microfluidic device. A higher tumor invasion was observed in a low-stiffness matrix than a high-stiffness matrix. The physical characterizations revealed how the stiffness is controlled by the density of polymer chain networks and porosity. The biological assays revealed how the structural properties of the gelatin matrix and hypoxia in tumor progression impact cell invasion. The cell spheroids' responses underscore the importance of replicating physical and structural properties to mimic tumor response. This work can contribute to personalized medicine by making more effective, tailored cancer models.

The effect of female breast surface area on heat-activated sweat gland density and output.

Female development includes significant morphological changes across the breast. Yet, whether differences in breast surface area (BrSA) modify sweat gland density and output remains unclear. The present study investigated the relationship between BrSA and sweat gland density and output in 22 young to middle-aged women (28 10years) of varying breast sizes (BrSA range: 147-561cm2) during a submaximal run in a warm environment (32 0.6°C; 53 1.7% relative humidity). Local sweat gland density and local sweat rate (LSR) above and below the nipple and at the bra triangle were measured. Expired gases were monitored for the estimation of evaporative requirements for heat balance (Ereq, in W/m2). Associations between BrSA and (i) sweat gland density; (ii) LSR; and (iii) sweat output per gland for the breast sites were determined via correlation and regression analyses. Our results indicated that breast sweat gland density decreased linearly as BrSA increased (r=-0.76, P<0.001), whereas sweat output per gland remained constant irrespective of BrSA (r=0.29, P=0.28). This resulted in LSR decreasing linearly as BrSA increased (r=-0.62, P=0.01). Compared to the bra triangle, the breast had a 64% lower sweat gland density (P<0.001), 83% lower LSR (P<0.001) and 53% lower output per gland (P<0.001). BrSA (R2=0.33, P=0.015) explained a greater proportion of variance in LSR than Ereq (in W/m2) (R2=0.07, P=0.538). These novel findings extend the known relationship between body morphology and sweat gland density and LSR, to the female breast. This knowledge could innovate user-centred design of sports bras by accommodating breast size-specific needs for sweat management, skin wetness perception and comfort.

Synergic Surface Modifications of PbS Quantum Dots by Sodium Acetate in Solid-State Ligand Exchange toward Short-Wave Infrared Photodetectors.

PbS quantum dots (QDs) are promising for short-wave infrared (SWIR) photodetection and imaging. Solid-state ligand exchange (SSLE) is a low-fabrication-threshold QD solid fabrication method. However, QD treatment by SSLE remains challenging in seeking refined surface passivation to achieve the desired device performance. This work investigates using NaAc in the ligand exchange process to enhance the film morphology and electronic coupling configuration of QD solids. By implementing various film and photodetector device characterization studies, we confirm that adding NaAc with a prominent adding ratio of 20 wt % NaAc with tetrabutylammonium iodide (TBAI) in the SSLE leads to an improved film morphology, reduced surface roughness, and decreased trap states in the QD solid films. Moreover, compared to the devices without NaAc treatment, those fabricated with NaAc-treated QD solids exhibit an enhanced performance, including lower dark current density (<100 nA/cm2), faster response speed, higher responsivity, detectivity, and external quantum efficiency (EQE reaching 25%). The discoveries can be insightful in developing efficient, low-cost, and low-fabrication-threshold QD SWIR detection and imager applications.

Optical Coherence Tomography Angiography Retinal Imaging Associations With Burden of Small Vessel Disease and Amyloid Positivity in the Brain.

Alzheimer disease (AD) and other dementias are associated with vascular changes and amyloid deposition, which may be reflected as density changes in the retinal capillaries. These changes may can be directly visualized and quantified with optical coherence tomography angiography (OCTA), making OCTA a potential noninvasive preclinical biomarker of small vessel disease and amyloid positivity. Our objective was to investigate the feasibility of retinal imaging metrics as noninvasive biomarkers of small vessel disease and amyloid positivity in the brain. We investigated associations between OCTA and neuroimaging and cognitive metrics in 41 participants without dementia from the Mayo Clinic Study of Aging and Alzheimer's Disease Research Center. OCTA metrics included superficial, deep, and full retina capillary density of the fovea, parafovea, and macula as well as the area of the foveal avascular zone (FAZ). Neuroimaging metrics included a high burden of white matter hyperintensity (WMH), presence of cerebral microbleeds (CMB), lacunar infarcts, and amyloid positivity as evidenced on positron emission tomography (PET), whereas cognitive metrics included mini-mental status examination (MMSE) score. We performed generalized estimating equations to account for measurements in each eye while controlling for age and sex to estimate associations between OCTA metrics and neuroimaging and cognitive scores. Associations between OCTA and neuroimaging metrics were restricted to the fovea. OCTA showed decreased capillary density with high burden of WMH in both the superficial (P = 0.003), deep (P = 0.004), and full retina (P = 0.01) in the fovea but not the parafovea or whole macula. Similarly, participants with amyloid PET positivity had significantly decreased capillary density in the superficial fovea (P = 0.027) and deep fovea (P = 0.03) but higher density in the superficial parafovea (P = 0.038). Participants with amyloid PET positivity also had a significantly larger FAZ (P = 0.031), whereas in those with high WMH burden the difference did not reach statistical significance (P = 0.075). There was also a positive association between MMSE and capillary density of the full retina within the fovea (P = 0.037) and in the superficial parafovea (P = 0.046). No associations were found between OCTA metrics and presence of CMB or presence of lacunar infarcts. The associations of lower foveal capillary density with cerebral WMH and amyloid positivity suggest that further research is warranted to evaluate for shared mechanisms of disease between small vessel disease and AD pathologies.

Enhancing the mechanical and electrochemical corrosion properties of Cu composites via manipulation of intragranular graphene quantum dots cluster

Intragranular distribution of reinforcements is highly valued for simultaneously improving strength and corrosion resistance in metal composites. Here, we manipulated zero-dimensional graphene quantum dots (GQDs) clusters into Cu grain interiors via a “nanodispersion-in-grains” strategy. The uniformly dispersed GQDs clusters activate multiple hardening mechanisms resulted in superior mechanical strengthening efficiency (Seff = 228). Furthermore, GQDs clusters contribute to induce the twin domains in composites via forming high stress field, which would elevate the grain boundary stability and in turn restrained the corrosion process. Compared with pure Cu, 0.2 GQDs/Cu composite has a lower corrosion current density (1.50 × 10−5 A cm−2), reducing the corrosion rate by 31.2%. Our work has provided a feasible route to broaden the Cu composites application as reliable structural components.

Sex hormones differently regulate lipid metabolism genes in primary human hepatocytes

BackgroundPrevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) is higher in men than in women. Hormonal and genetic causes may account for the sex differences in MASLD. Current human in vitro liver models do not sufficiently take the influence of biological sex and sex hormones into consideration.MethodsPrimary human hepatocytes (PHHs) were isolated from liver specimen of female and male donors and cultured with sex hormones (17β-estradiol, testosterone and progesterone) for up to 72 h. mRNA expression levels of 8 hepatic lipid metabolism genes were analyzed by RT-qPCR. Sex hormones and their metabolites were determined in cell culture supernatants by LC-MS analyses.ResultsA sex-specific expression was observed for LDLR (low density lipoprotein receptor) with higher mRNA levels in male than female PHHs. All three sex hormones were metabolized by PHHs and the effects of hormones on gene expression levels varied depending on hepatocyte sex. Only in female PHHs, 17β-estradiol treatment affected expression levels of PPARA (peroxisome proliferator-activated receptor alpha), LIPC (hepatic lipase) and APOL2 (apolipoprotein L2). Further changes in mRNA levels of female PHHs were observed for ABCA1 (ATP-binding cassette, sub-family A, member 1) after testosterone and for ABCA1, APOA5 (apolipoprotein A-V) and PPARA after progesterone treatment. Only the male PHHs showed changing mRNA levels for LDLR after 17β-estradiol and for APOA5 after testosterone treatment.ConclusionsMale and female PHHs showed differences in their expression levels of hepatic lipid metabolism genes and their responsiveness towards sex hormones. Thus, cellular sex should be considered, especially when investigating the pathophysiological mechanisms of MASLD.

Electoral incentives to target investment in roads: Evidence from Italian municipalities

Using a comprehensive dataset on Italian municipalities, we test whether investments in road services are affected by political manipulations motivated by the need of targeting a specific group of voters (construction firms). We show that road services investment in the year before election is 26% higher in municipalities with low density of construction firms and 40% higher in municipalities with high density of construction firms than in the electoral year. This result is confirmed by the fact that in the pre-electoral year the probability that public procurement on road services is assigned to a local firm increases by 52 percentage points with respect to the electoral year, for municipalities with high density of construction firms. Finally, we do not detect any relationship between investments in road services and the local road safety. These findings suggest that politicians manipulate investments in road services for re-electoral purposes.

Preparation and characterization of micro-cellular melamine foam supported SiO2 aerogel for building thermal insulation

This study aims to complement the advantages of SiO2 aerogel and melamine foam (MF) to produce high-performance building insulation materials. The optimal sol–gel scheme was determined by controlling system temperature, water content, amount of ethanol and amount of acid-base catalyst (orthogonal experiment). The density and porosity of MF/SiO2 aerogel were regulated by adjusting aging time, aging temperature and type of aging agent. Furthermore, the effects of different volume fractions hydrophobic modifier on the surface free energy and wettability of MF/SiO2 aerogel were also investigated. The experiment results showed that the prepared MF/SiO2 aerogel satisfies requirements for low density (0.089 g/cm3), low thermal conductivity at room temperature (0.0256 W m−1·K−1), and excellent hydrophobic performance (the contact angle was 140.1°). Meanwhile, it was found that SiO2 aerogel was stably and uniformly distributed in the pores of the MF and effectively enhanced the mechanical property (a maximum compressive strength of 0.2058 MPa), heat-shielding performance, flame retardant property, and sound absorption capacity(αmax = 0.76, αave = 0.31).Therefore, the MF/SiO2 aerogel composites exhibit exceptional application potential in comparison to conventional building insulation materials (such as EPS, Rock wool board, etc.) due to their significantly low thermal conductivity and remarkable flame retardant properties.

The in vitro effect of myeloperoxidase oxidized LDL on THP-1 derived macrophages.

Cardiovascular diseases (CVDs) linked to atherosclerosis remains the leading cause of death worldwide. Atherosclerosis is primarily caused by the accumulation of oxidized forms of low density lipoprotein (LDL) in macrophages (MΦs) in the subendothelial layer of arteries leading to foam cell and fatty streak formation. Many studies suggest that LDL that is modified by myeloperoxidase (MPO) is a key player in the development of atherosclerosis. MΦs can adopt a variety of functional phenotypes that include mainly the proinflammatory M1 and the anti-inflammatory M2 MΦ phenotypes which are both implicated in the process of atherogenesis. In fact, MΦs that reside in atherosclerostic lesions were shown to express a variety of phenotypes ranging between the M1- and M2 MΦ types. Recently, we pointed out the involvement of MPO oxidized-LDL (Mox-LDL) in increasing inflammation in MΦs by reducing their secretion of IL-10. Since little is known about Mox-LDL-mediated pro-atherosclerostic responses in MΦs, our study aimed at analyzing the in vitro effects of Mox-LDL at this level through making use of the well-established model of human THP-1-derived Mφs. Our results demonstrate that Mox-LDL has no effect on apoptosis, reactive oxygen species (ROS) generation and cell death in our cell model; yet, interestingly, our results show that Mox-LDL is significantly engulfed at a higher rate in the different MΦ subtypes supporting its key role in foam cell formation during the progression of the disease as well as previous data that were generated using another primary MΦ cell model of atherosclerosis.

Study on the effect of Sc and Zr addition on microstructure, mechanical property and fracture behavior of electron beam welded Be-Al alloys

Because of various excellent properties of low density, high specific strength and stiffness, high modulus, good thermal stability and corrosion-resistant, beryllium-aluminum (Be-Al) alloys have shown great potential to be used in nuclear industries. However, Be-Al alloys suffer from the bottlenecks of low solubility between Be and Al and the lack of effective technology for fabricating large-sized products. Herein, based on Sc and Zr addition, Be-Al-Sc-Zr alloys are successfully fabricated by conducting the electron beam welding (EBW) technology, and the effect of Sc and Zr addition on microstructure, mechanical property and fracture behavior of Be-Al-Sc-Zr alloys is studied. Microstructural characterizations show that both the EBWed Be-Al and Be-Al-Sc-Zr alloys exhibit two distinct zones of substrate zone (SZ) and fusion zone (FZ). Compared to grain size of the SZ and FZ in Be-Al alloys, grain sizes of these two zones in Be-Al-Sc-Zr alloys are significantly refined, thus leading to ultimate tensile strength (UTS) of the Be-Al-Sc-Zr alloys (~176MPa) approximately 150% higher than that of the Be-Al alloys (~118MPa). Besides, a newly generated third phase (TP), which is confirmed as Be13(Scx, Zr1-x), forms within Al phase in both SZ and FZ of the Be-Al-Sc-Zr alloys. Different from fracture behavior of Be-Al alloys that preferentially fractures within Al phase or near the Be/Al interface, fracture of the Be-Al-Sc-Zr alloys is prone to occur within Be phase. As revealed by the calculation results of finite element method (FEM), the underlying mechanism for different fracture behaviors mainly ascribes to that the reinforcement of the Al phase and the existence of the newly formed TP can greatly increases the internal stress and even causes stress concentration within Be phase of the Be-Al-Sc-Zr alloys. The present findings may provide more insights to the micro-alloying and deformation mechanism of Be-Al alloys that with enhanced mechanical properties.

Subcutaneous coding via laser directed energy deposition (DED-LB) for unalterable component identification

Part identification has become a priority in manufacturing, especially when it comes to the additive manufacturing (AM) industry, where the counterfeit printing of almost any digitalized component is possible. As a means of avoiding forgery, the development of non-detectable labels, or digital passports is necessary. In the present work, a novel methodology for printing subcutaneous coding on aeronautical parts is proposed thanks to the multimaterial capabilities of the laser based directed energy deposition (DED-LB). The coding is based on embedding a dot pattern of a high-density alloy on a small area of a lower density component, which once covered and finished generates a pattern only visible by X-ray imagining. The viability of the proposed methodology is proven by embedding WC particles on a Ti6Al4V substrate. Firstly, the most relevant process parameters are optimized to ensure a sharp and a readable code, and their geometry is analysed by means of industrial Computed Tomography (CT). Also, the metallurgical quality and chemical composition of the generated dots is evaluated by Scanning Electron Microscope (SEM). Finally, a demonstrator part is fabricated with a hidden code. The code readability and the mechanical properties are tested to ensure the feasibility of the developed methodology.

A coral-like skeleton carbon aerogel achieves good mechanical and thermal insulation properties

A coral-like network carbon aerogel was synthesized by introducing acid-modified carbon nanofibers (a-CNF) into phenolic (PR) aerogel through chemical grafting, followed by high-temperature carbonization. The bonding interaction between a-CNF and PR was analyzed by FT-IR spectroscopy. The microstructure of a-CNF/PR composite aerogel (a-CNF/PRA) was studied by SEM and pore structure analysis. The results showed that introducing 5 wt% of a-CNF was most favorable for forming a porous network of a-CNF/PRA. SEM photographs and pore structure analysis indicated that a-CNF/C composite aerogel (a-CNF/CA) developed a stable porous skeletal structure during carbonization. TEM images revealed that the complete porous skeleton consisted of a-CNF encapsulated by carbon layers. The carbonization shrinkage of a-CNF/CA was only 26.53% due to the presence of a-CNF as the skeleton support. Compared to carbon aerogel, a-CNF/CA exhibited lower density (0.072 g·cm-3), thermal conductivity (0.0452 W·m-1·K-1), and higher compressive strength (up to 3.26 MPa) up to 3.26 MPa than that of carbon aerogel (1.21 MPa). These findings confirmed the excellent mechanical and thermal insulation properties of a-CNF/CA.

PD-L1+ macrophage and tumor cell abundance and proximity to T cells in the pretreatment large B-cell lymphoma microenvironment impact CD19 CAR-T cell immunotherapy efficacy.

CD19-targeted chimeric antigen receptor T-cell (CAR-T) immunotherapy has transformed the management of relapsed/refractory large B-cell lymphoma (LBCL), yet durable remissions are observed in less than half of treated patients. The tumor microenvironment (TME) is a key and understudied factor impacting CD19 CAR-T therapy outcomes. Using NanoString nCounter transcriptome profiling (n = 24) and multiplex immunohistochemistry (mIHC, n = 15), we studied the TME in pretreatment biopsies from patients with LBCL undergoing CD19 CAR-T therapy. Patients who achieved complete response (CR) after CAR-T therapy demonstrated higher expression of genes associated with T-cell trafficking and function, whereas those who did not achieve CR had higher expression of genes associated with macrophages and T-cell dysfunction. Distinct patterns of immune infiltration and fibrosis in the TME were associated with CAR-T therapy outcomes, and these findings were corroborated using artificial intelligence-assisted image analyses. Patients who achieved CR had a lower proportion of the biopsy occupied by an interspersed immune infiltrate and a higher proportion of hypocellular/fibrotic regions. Furthermore, mIHC revealed lower density of CD4+ T cells and higher densities of both macrophages and tumor cells expressing PD-L1 in non-CR patients. Spatial analysis revealed that PD-1+ T cells were in close proximity to PD-L1+ macrophages or PD-L1+ tumor cells in patients who did not compared to those who did achieve CR after CAR-T therapy. These findings suggest that morphologic patterns in the TME and engagement of the PD-1/PD-L1 axis in pretreatment biopsies may impact CD19 CAR-T immunotherapy response in patients with LBCL.