Air-coupled ultrasonic transducer based on lead-free piezoceramics prepared by digital light processing 3D printing.

Piezoelectric composite ceramics, as the key components of ultrasonic transducers, have their vibration modes, electromechanical coupling performance, and acoustic impedance closely related to the volume fraction of ceramics. This study employed a novel digital light processing 3D printing technique (DLP) to fabricate 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 (BCZT)-based 1-3 piezoelectric composite ceramics with different ceramic volume fractions (15.6 %, 23.5 %, 36.2 %, 48.4 %, 59.5 %). It demonstrates the suitability of the DLP process for the fabrication of 1-3 piezoelectric composite ceramics and investigates the influence of ceramic volume fraction on the performance of these ceramics. When the piezoelectric ceramic volume fraction was 59.5 %, the piezoelectric coefficient effective d33 of the 1-3 piezoelectric composite device reached 315 pC/N, demonstrating excellent piezoelectric performance. The acoustic impedance Z was 16.3 MRayl, and the thickness electromechanical coupling coefficient kt was 0.55, indicating high energy conversion efficiency. The air-coupled ultrasonic transducer prepared from the 1-3 piezoelectric composite ceramics with a ceramic volume fraction of 59.5 % exhibited a round-trip insertion loss (IL) of -70.32 dB and a -6 dB bandwidth (BW-6dB) of 7.42 %. This work provides a more convenient and new method for the preparation of lead-free piezoelectric ceramic ultrasonic transducers.

Routine evaluation of HBV-specific T cell reactivity in chronic hepatitis B using a broad-spectrum T-cell epitope peptide library and ELISpot assay.

BACKGROUND: The clinical routine test of HBV-specific T cell reactivity is still limited due to the high polymorphisms of human leukocyte antigens (HLA) in patient cohort and the lack of universal detection kit, thus the clinical implication remains disputed. METHODS: A broad-spectrum peptide library, which consists of 103 functionally validated CD8+ T-cell epitopes spanning overall HBsAg, HBeAg, HBx and HBpol proteins and fits to the HLA polymorphisms of Chinese and Northeast Asian populations, was grouped into eight peptide pools and was used to establish an ELISpot assay for enumerating the reactive HBV-specific T cells in PBMCs. Totally 294 HBV-infected patients including 203 ones with chronic hepatitis B (CHB), 13 ones in acute resolved stage (R), 52 ones with liver cirrhosis (LC) and 26 ones with hepatocellular carcinoma (HCC) were detected, and 33 CHB patients were longitudinally monitored for 3 times with an interval of 3-5 months. RESULTS: The numbers of reactive HBV-specific T cells were significantly correlated with ALT level, HBsAg level, and disease stage (R, CHB, LC and HCC), and R patients displayed the strongest HBV-specific T cell reactivity while CHB patients showed the weakest one. For 203 CHB patients, the numbers of reactive HBV-specific T cells presented a significantly declined trend when the serum viral DNA load, HBsAg, HBeAg or ALT level gradually increased, but only a very low negative correlation coefficient was defined (r = - 0.21, - 0.21, - 0.27, - 0.079, respectively). Different Nucleotide Analogs (NUCs) did not bring difference on HBV-specific T cell reactivity in the same duration of treatment. NUCs/pegIFN-α combination led to much more reactive HBV-specific T cells than NUCs monotherapy. The dynamic numbers of reactive HBV-specific T cells were obviously increasing in most CHB patients undergoing routine treatment, and the longitudinal trend possess a high predictive power for the hepatitis progression 6 or 12 months later. CONCLUSION: The presented method could be developed into an efficient reference method for the clinical evaluation of cellular immunity. The CHB patients presenting low reactivity of HBV-specific T cells have a worse prognosis for hepatitis progression and should be treated using pegIFN-α to improve host T-cell immunity.

Preliminary study of low-pressure ionization chamber for online dose monitoring in FLASH carbon ion radiotherapy.

The FLASH effect of carbon ion therapy has recently attracted significant attention from the scientific community. However, the radiobiological mechanism of the effect and the exact therapeutic conditions are still under investigation. Therefore, the dosimetry accuracy is critical for testing hypotheses about the effect and quantifying FLASH Radiotherapy. In this paper, the FLASH ionization chamber at low-pressure was designed, and its dose rate dependence was verified with the Faraday cup. In addition, the dose response was tested under the air pressure of the ionization chamber of 10 mbar, 80 mbar and 845 mbar, respectively. The results showed that when the pressure was 10 mbar, the dose linearity was verified and calibrated at the dose rate of ∼50 Gy s-1, and the residuals were less than 2%. In conclusion, the FLASH ionization chamber is a promising instrument for online dose monitoring.

Intermittent cold stimulation affects energy metabolism and improves stress resistance in broiler heart.

To investigate the effect of intermittent cold stimulation on cardiac energy metabolism and cold resistance of broilers, 288 broilers were divided into 3 groups: control group (CC) and 2 cold stimulation groups (CS3 and CS9). The CS3 and CS9 groups received cold stimulation at temperatures of 3°C and 9°C lower than CC group for 5 h from d 15 to 35. Three groups were subjected to acute cold stress (ACS) of 10°C for 12 and 24 h at 44 d. Performance, cardiac histopathological changes, heat shock proteins (HSPs), and lipid metabolism levels were measured. Results showed that the performance was not different among groups at 22 and 29 d (P > 0.05), but the mRNA levels of Acyl CoA synthase long-chain family member 1 (ACSL1) and acyl-coenzyme oxidase (ACO) in CS group were upregulated compared to CC group (P < 0.05). At 36 d, the performance of the CS3 group was better than the other 2 groups, myocardial structure was normal and other lipid metabolism indexes, except for peroxisome proliferator-activated receptor coactivator 1α (PGC-1α) levels, were similar to those of CC group (P > 0.05). The myocardial fiber disorder, Triglyceride (TG), and leptin (LEP) contents were significantly lower in CS9 group than in CC and CS3 groups at 36 d (P < 0.05). The HSP protein levels were significantly higher in CS group than in CC group before ACS (P < 0.05). After 24 h of ACS, the mRNA of lipid metabolism genes, the protein levels of HSP40 and HSP60, and the contents of TG and LEP in the CS3 group were upregulated compared to other groups. The CC and CS9 groups showed myocardial structure was destroyed, with lower TG and LEP levels compared to before ACS (P < 0.05). Therefore, cold stimulation at 3°C lower than the normal feeding temperature for 5 h did not impair performance but can increase the resistance of broilers to ACS by promoting lipid metabolism.

Mild Intermittent Cold Stimulation Affects Cardiac Substance Metabolism via the Neuroendocrine Pathway in Broilers.

This study aimed to investigate the impact of cold adaptation on the neuroendocrine and cardiac substance metabolism pathways in broilers. The broilers were divided into the control group (CC), cold adaptation group (C3), and cold-stressed group (C9), and experimental period was divided into the training period (d 1-35), recovery period (d 36-43), and cold stress period (d 43-44). During the training period, the CC group was reared at ambient temperature, while C3 and C9 groups were reared at 3 °C and 9 °C lower than the ambient temperature, respectively, for 5 h/d at 1 d intervals. During the recovery period, all the groups were maintained at 20 °C. Lastly, during the cold stress period, the groups were divided into two sub-groups, and each sub-group was placed at 10 °C for 12 h (Y12) or 24 h (Y24) for acute cold stimulation. The blood, hypothalamic, and cardiac tissues samples were obtained from all the groups during the training, recovery, and acute stress periods. The results revealed that the transcription of calcium voltage-gated channel subunit alpha 1 C (CACNAIC) was increased in the hypothalamic tissues of the C3 group (p < 0.05). Moreover, compared to the CC group, the serum norepinephrine (NE) was increased in the C9 group (p < 0.05), but insulin (INS) was decreased in the C9 group (p < 0.05). In addition, the transcription of the phosphoinositide-3 kinase (PI3K), protein kinase B (Akt), mammalian target of rapamycin (mTOR), SREBP1c, FASN, ACC1, and SCD genes was down-regulated in the C3 and C9 groups (p < 0.05); however, their expression increased in the C3 and C9 groups after acute cold stimulation (p < 0.05). Compared to the CC group, the transcription of forkhead box O1 (FoxO1), PEPCK, G6Pase, GLUT1, HK1, PFK, and LDHB genes was up-regulated in the C3 and C9 groups (p < 0.05. Furthermore, compared to the CC and C9 groups, the protein and mRNA expressions of heat shock protein (HSP) 70 and HSP90 were significantly increased in the C3 group (p < 0.05). These results indicate that intermittent cold training can enhance cold stress tolerance in broilers by regulating their neuroendocrine and cardiac substance metabolism pathways.

Cold stimulation causes oxidative stress, inflammatory response and apoptosis in broiler heart via regulating Nrf2/HO-1 and NF-κB pathway.

To investigate the effect of cold stimulation on heart, 300 1-day-old female broilers were divided into control (CON) and two cold stimulation (CS3 and CS9) groups. Birds in CON group were reared in normal ambient temperature during day 1-43; while birds in CS3 and CS9 groups were reared at 3 °C and 9 °C below CON group for 5 h at 1-day intervals from day 15 to day 35, respectively. Heart tissues were collected at day 22, 29, 36, and 43 to determine the indexes related to oxidative stress, inflammation and apoptosis. The H&E staining displayed that inflammatory cell infiltration and myocardial fiber break were obviously observed in CS9 group, and cardiac pathological score in CS9 group was higher than CON and CS3 groups (P < 0.05) at day 22, 36, and 43. Overall, compared to CON group, the concentrations of MDA and H2O2 were elevated, the activities of SOD, CAT, GPx, and T-AOC were reduced, and mRNA expression of CAT, GPx, SOD, nuclear factor-erythroid 2-related factor 2 (Nrf2), and heme oxygenase-1 (HO-1) was downregulated in CS9 group at each time-point (P < 0.05). Compared to CON group, mRNA expression of NF-κBp65, COX-2, iNOS, PTGEs, TNF-α, and IL-1ß, and mRNA and protein expression of Bax, Bak, Cyt-c, caspase-3, and caspase-9 were increased, while Bcl-2 and Bcl-2/Bax ratio were decreased in CS9 group (P < 0.05) at the most detected time-points. There were no significant differences in the levels of indexes associated with oxidative stress, Nrf2/HO-1 antioxidant system, inflammation, and apoptosis between CON and CS3 groups at the most detected time-points (P > 0.05). Therefore, this study suggests that severe cold stimulation at 9 °C below normal rearing temperature induces cardiomyocyte inflammation and apoptosis by regulating Nrf2/HO-1 pathway-related oxidative stress in broilers, and mild cold stimulation of CS3 group can improve the adaptability of hearts to cold environment.

Appropriate cold stimulation changes energy distribution to improve stress resistance in broilers.

Appropriate cold stimulation can improve stress resistance in broilers and alleviate the adverse impacts of a cold environment. To investigate the effects of intermittent mild cold stimulation (IMCS) on energy distribution in the livers of broilers, 96 healthy 1-d-old Ross-308 male broilers were randomly divided into the control group (CC) and the cold stimulation group (H5). The CC group was raised at a normal thermal temperature, i.e., 35 °C until 3 d, after which the temperature was dropped gradually by 0.5 °C/d until 20 °C at 33 d. This temperature was maintained until 49 d. The H5 group was raised at the same temperature as the CC group until 14 d (35 to 29.5 °C) and at 3 °C below the temperature of the CC group starting at 0930 hours for 5 h every other day from 15 to 35 d (26 to 17°C). The temperature was returned to 20 °C at 36 d and maintained until 49 d. At 50 d, all broilers were subjected to acute cold stress (ACS) at 10 °C for 6 and 12 h. We found that IMCS had positive effects on production performance. Using transcriptome sequencing of the broiler livers, 327 differentially expressed genes (DEG) were identified, and highly enriched in fatty acid biosynthesis, fatty acid degradation, and the pyruvate metabolism pathway. When compared to the CC group, the mRNA levels of ACAA1, ACAT2, ACSL1, CPT1A, LDHB, and PCK1 in the H5 group were increased at 22 d (P < 0.05). The LDHB mRNA level was upregulated in the H5 group at 29 d compared to the CC group (P < 0.05). After 21 d of IMCS (at 36 d), the mRNA expression levels of ACAT2 and PCK1 were found to be significantly increased in the H5 group compared to the CC group (P < 0.05). Seven days after the IMCS had ended (at 43 d), the mRNA levels of ACAA1, ACAT2, and LDHB in the H5 group were higher than in the CC group (P < 0.05). The mRNA levels of heat shock protein (HSP) 70, HSP90, and HSP110 in the H5 group were higher than in the CC group after 6 h of ACS (P < 0.05). The protein levels of HSP70 and HSP90 in the H5 group were downregulated after 12 h of ACS, compared to the CC group (P < 0.05). These results indicated that IMCS at 3 °C lower than the normal temperature could improve energy metabolism and stress resistance in the livers of broilers, alleviate the damage of short-term ACS on broilers, help broilers adapt to the low temperature, and maintain stable of energy metabolism in the body.

Cold stimulation has a great impact on broilers. Excessive cold stimulation can lead to damage, while intermittent mild cold stimulation (IMCS) can make broilers adapt to the cold environment. Low temperature will make the body produce lots of heat to maintain metabolic stability. The liver controls the energy metabolism, and the avian livers are the main organ regulating lipid metabolism. In this study, the broilers of different ages were subjected to cold stimulation training and then acute cold stress (ACS). We found that IMCS had positive effects on production performance. Through transcriptome sequencing, we found that the differentially expressed genes were highly enriched in the energy metabolism pathway, and the expression levels of the most key genes and heat shock proteins were upregulated. The stress resistance was also enhanced, which could alleviate the damage of short-term ACS to the body. The broilers gradually adapted to the low-temperature environment and finally established cold adaptation. The findings of this work will be helpful to the development of animal husbandry in cold regions and improve animal welfare.

Multiple-ion Management of Perovskites by Regulating Spatial Distribution of Hydroxyls in Oligosaccharides.

Suppressing migrations of intrinsic and extrinsic ions (e.g., Pb2+ , I- , FA+ /MA+ , and Li+ ) in organic-inorganic hybrid perovskites is critical for alleviating the hysteresis and degradation of perovskite solar cells (PSCs). However, various additives reported for that purpose usually interact with one or two types of those ions, not inhibiting multiple-ion migrations simultaneously. Two oligosaccharides (ß-cyclodextrin (ß-CD) and maltotetraose (G4)), containing 14 hydroxyls (-OH) with different spatial distributions, for the suppression of multiple-ion migrations in PSCs is herein employed. Compared to linear arrangement of -OH in G4, annular distribution of -OH around wide and narrow rims of ß-CD can form supramolecular multi-site interactions in a focal manner with various ions, more effectively capturing and immobilizing these migrated ions. With this multiple-ion management strategy, ß-CD-based PSCs exhibit an impressive efficiency of 24.22% with negligible hysteresis and excellent device stability. This work highlights the significances of multi-site interactions and molecular configuration of the additive for inhibiting multi-ion migrations in PSCs.

Improving the Thermal Stability of the Fine-Grained Structure in the Cu-15Ni-8Sn Alloy during Solution Treatment by the Additions of Si and Ti.

Grain refinement has been found to be an effective method for simultaneously enhancing strength and toughness. To avoid the sharp coarsening of grains in Cu-Ni-Sn alloys during solution treatment and thereby overcoming the tradeoff between strength and ductility, this work attempted to modify the composition and improve the thermal stability of the fine-grained structure in Cu-Ni-Sn alloys. The grain growth behavior during a solution treatment of the Cu-15Ni-8Sn alloys with/without Si and Ti additions was systematically investigated. The result reveals that compared to the grain size of 146 µm in the based alloy (without trace additions) after solution processing at 1073 K for 2 h, the fine-grained structure with a size below 20 µm is maintained owing to the benefit from Si and Ti addition. It was observed that the addition of Si and Ti offer the inhibition effect on the dissolution of the γ phase and Ni16Si7Ti6 particles after solution treatment. The grain boundary movement is severely hindered by these two aspects: the pinning effect from these particles, and the drag effect induced by additional solute atoms. Based on the analysis of grain growth kinetics, the activation energy of grain growth is increased from 156 kJ/mol to 353 kJ/mol with the addition of Si and Ti.

Effect of intermittent mild cold stimulation on intestinal immune function and the anti-stress ability of broilers.

A total of 240 healthy 1-day-old Ross 308 male broilers were randomly divided into 3 groups (CS0 group, CS3 group, and CS6 group), with 5 replicates in each group and 16 broilers in each replicate, in order to evaluate the effects of intermittent mild cold stimulation (IMCS) on the intestinal immune function and anti-cold stress ability of broilers after acute cold stress. The mRNA expression levels of cytokines and Toll-like receptors (TLRs) in the duodenum and jejunum were detected at the end of cold stimulation (36 d), 2 wk after recovery (50 d), and after acute cold stress (Y6). In addition, the mRNA and protein expression levels of heat shock proteins (HSPs) were measured before and after acute cold stress. The experimental data were statistically processed using 1-way ANOVA and Duncan's multiple comparisons. The results showed that the mRNA expression levels of IL2, IL8, IFN γ, TLR7, and TLR21 in the duodenum and IL2 and IFN Î³ in jejunum were significantly higher in the CS6 group than in the CS0 and CS3 groups at 36 d (P < 0.05). All TLR levels in the jejunum were significantly lower in the CS3 group than in the CS0 and CS6 groups at 36 d (P < 0.05). After 6 h of acute cold stress, in the duodenum, the mRNA expression levels of IL6 and IL8 were significantly decreased in the CS0 and CS6 groups compared to levels at 50 d (P < 0.05), while levels in the CS3 group remained stable (P > 0.05). Compared with 50 d, the expression level of HSP mRNA in the jejunum in the CS3 group was relatively stable compared to that in the CS0 and CS6 groups after acute cold stress (P > 0.05). At the protein level, the HSP60 expression level in the duodenum and HSP40, HSP60, and HSP70 expression levels in the jejunum were significantly higher in the CS3 group than in the CS0 and CS6 groups after acute cold stress (P < 0.05). In conclusion, cold stimulation training at 3℃/3 h lower than the conventional feeding temperature can improve the intestinal immune function and anti-stress ability of broilers.

Roles that Organic Ammoniums Play on the Surface of the Perovskite Film: A Review.

The roles of organic ammonium salts (OASs) which are widely used for the surface treatment of the perovskite film, including formation of 2D perovskites, direct surface passiviation, and other effects, have been reviewed. The influencing factors for these roles of OASs are also discussed, which are important for improved efficiency and stability of perovskite solar cells. More information can be found in the Review article by X. Guo and co-workers. (DOI: 10.1002/chem.202203001).

Asymmetric Divergent Synthesis of ent-Kaurane-, ent-Atisane-, ent-Beyerane-, ent-Trachylobane-, and ent-Gibberellane-type Diterpenoids.

A unified strategy toward asymmetric divergent syntheses of nine C8-ethano-bridged diterpenoids A1-A9 (candol A, powerol, sicanadiol, epi-candol A, atisirene, ent-atisan-16α-ol, 4-decarboxy-4-methyl-GA12, trachinol, and ent-beyerane) has been developed based on late-stage transformations of common synthons having ent-kaurane and ent-trachylobane cores. The expeditious assembly of crucial advanced ent-kaurane- and ent-trachylobane-type building blocks is strategically explored through a regioselective and diastereoselective Fe-mediated hydrogen atom transfer (HAT) 6-exo-trig cyclization of the alkene/enone and 3-exo-trig cyclization of the alkene/ketone, showing the multi-reactivity of densely functionalized polycyclic substrates with πC═C and πC═O systems in HAT-initiated reactions. Following the rapid construction of five major structural skeletons (ent-kaurane-, ent-atisane-, ent-beyerane-, ent-trachylobane-, and ent-gibberellane-type), nine C8-ethano-bridged diterpenoids A1-A9 could be accessed in the longest linear 8 to 11 steps starting from readily available chiral γ-cyclogeraniol 1 and known chiral γ-substituted cyclohexenone 2, in which enantioselective total syntheses of candol A (A1, 8 steps), powerol (A2, 9 steps), sicanadiol (A3, 10 steps), epi-candol A (A4, 8 steps), ent-atisan-16α-ol (A6, 11 steps), and trachinol (A8, 10 steps) are achieved for the first time.

A systemic review of T-cell epitopes defined from the proteome of SARS-CoV-2.

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection remains in a global pandemic, and no eradicative therapy is currently available. Host T cells have been shown to play a crucial role in the antiviral immune protection and pathology in Coronavirus disease 2019 (COVID-19) patients; thus, identifying sufficient T-cell epitopes from the SARS-CoV-2 proteome can contribute greatly to the development of T-cell epitope vaccines and the precise evaluation of host SARS-CoV-2-specific cellular immunity. This review presents a comprehensive map of T-cell epitopes functionally validated from SARS-CoV-2 antigens, the human leukocyte antigen (HLA) supertypes to present these epitopes, and the strategies to screen and identify T-cell epitopes. To the best of our knowledge, a total of 1349 CD8+ T-cell epitopes and 790 CD4+ T-cell epitopes have been defined by functional experiments thus far, but most are presented by approximately twenty common HLA supertypes, such as HLA-A0201, A2402, B0702, DR15, DR7 and DR11 molecules, and 74-80% of the T-cell epitopes are derived from S protein and nonstructural protein. These data provide useful insight into the development of vaccines and specific T-cell detection systems. However, the currently defined T-cell epitope repertoire cannot cover the HLA polymorphism of major populations in an indicated geographic region. More research is needed to depict an overall landscape of T-cell epitopes, which covers the overall SARS-CoV-2 proteome and global patients.

Effects of Acute Cold Stress after Intermittent Cold Stimulation on Immune-Related Molecules, Intestinal Barrier Genes, and Heat Shock Proteins in Broiler Ileum.

Cold stress will have a negative impact on animal welfare and health. In order to explore the effect of intermittent cold stimulation training on the cold resistance of broilers. Immune-related and intestinal barrier genes were detected before and after acute cold stress (ACS), aiming to find an optimal cold stimulation training method. A total of 240 1-day-old Ross broilers (Gallus) were divided into three groups (G1, G2, and G3), each with 5 replicates (16 chickens each replicate). The broilers of G1 were raised at normal temperature, while the broilers of G2 and G3 were treated with cold stimulation at 3 °C lower than the G1 for 3 h and 6 h from 15 to 35 d, respectively, at one-day intervals. At 50 d, the ambient temperature for all groups was reduced to 10 °C for six hours. The results demonstrated that before ACS, IL6, IL17, TLR21, and HSP40 mRNA levels in G3 were apparently down-regulated (p < 0.05), while IL8 and Claudin-1 mRNA levels were significantly up-regulated compared with G1 (p < 0.05). After ACS, IL2, IL6, and IL8 expression levels in G3 were lower than those in G2 (p < 0.05). Compared to G2, Claudin-1, HSP90 mRNA levels, HSP40, and HSP70 protein levels were increased in G3 (p < 0.05). The mRNA levels of TLR5, Mucin2, and Claudin-1 in G2 and IL6, IL8, and TLR4 in G3 were down-regulated after ACS, while IL2, IL6, and IL17 mRNA levels in G2 and HSP40 protein levels in G3 were up-regulated after ACS (p < 0.05). Comprehensive investigation shows that cold stimulation at 3 °C lower than the normal feeding temperature for six hours at one day intervals can enhanced immune function and maintain the stability of intestinal barrier function to lessen the adverse effects on ACS in broilers.

Ameliorative effects of dietary selenium against cadmium toxicity on production performance and egg quality in laying hens.

In order to reveal the influences of supplemented dietary selenium (Se) on the suppressive effect of cadmium (Cd) toxicity on performance and egg properties of laying hens, the effects of co-treatment Se and Cd on the performance, egg quality, levels of amino acids and the antioxidant capacity of egg and serum were investigated. A total of 128 31-week-old laying hens were randomly distributed in four treatments, which were fed with the basic diet (0.2 mg/kg Se and 0.08 mg/kg Cd), and the basic diet with Se (1.1 mg/kg Se and 0.08 mg/kg Cd), Cd (0.2 mg/kg Se and 92.1 mg/kg Cd) and Se+Cd for 13 weeks, respectively. Hens supplemented with Cd led to an impairment on production performance and egg quality with decreased egg production (EP), egg mass (EM), feed intake (FI), eggshell color, eggshell thickness, yolk color, albumen height and haugh unit and increased the feed conversion ratio (FCR) (p < 0.05). Cd treatment decreased the contents of cysteine (Cys), histidine (His), lithium (Li), aluminum (Al), chromium (Cr), manganese (Mn), nickel (Ni), zinc (Zn), arsenic (As), Se, strontium (Sr), stannum (Sn), mercury (Hg) and thallium (Tl) and increased the contents of isoleucine (Ile) and Cd (p < 0.05). Cd destroyed the egg yolk and serum redox states with the increased concentration of malondialdehyde (MDA) and the decreased activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx) (p < 0.05). The expression levels of ovarian apoptotic genes (protein 53, Caspase9, Cytochrome c and Bcl-2 associated X protein) increased, and B-cell lymphoma 2 (Bcl-2) expression decreased in the Cd group (p < 0.05). Feeding Se significantly alleviated Cd-induced toxicity on performance and egg quality. Se+Cd treatment restored the balance between oxidation and antioxidant systems and modulated the elements' homeostasis and alleviated the changes in apoptotic-related genes expression levels. Se could alleviate the Cd toxicity to laying hens and their eggs but could not counteract all negative effects of Cd.

High-Resolution Electron Tomography of Ultrathin Boerdijk-Coxeter-Bernal Nanowire Enabled by Superthin Metal Surface Coating.

The rapid advancement of transmission electron microscopy has resulted in revolutions in a variety of fields, including physics, chemistry, and materials science. With single-atom resolution, 3D information of each atom in nanoparticles is revealed, while 4D electron tomography is shown to capture the atomic structural kinetics in metal nanoparticles after phase transformation. Quantitative measurements of physical and chemical properties such as chemical coordination, defects, dislocation, and local strain have been made. However, due to the incompatibility of high dose rate with other ultrathin morphologies, such as nanowires, atomic electron tomography has been primarily limited to quasi-spherical nanoparticles. Herein, the 3D atomic structure of a complex core-shell nanowire composed of an ultrathin Boerdijk-Coxeter-Bernal (BCB) core nanowire and a noble metal thin layer shell deposited on the BCB nanowire surface is discovered. Furthermore, it is demonstrated that a new superthin noble metal layer deposition on an ultrathin BCB nanowire could mitigate electron beam damage using an in situ transmission electron microscope and atomic resolution electron tomography. The colloidal coating method developed for electron tomography can be broadly applied to protect the ultrathin nanomaterials from electron beam damage, benefiting both the advanced material characterizations and enabling fundamental in situ mechanistic studies.

Effect of mild intermittent cold stimulation on thymus immune function in broilers.

This study aims to assess the effect of intermittent and mild cold stimulation (IMCS) on thymus function and the ability of 1-day-old male Ross 308 broilers to withstand cold. Four hundred broilers were reared under normal and mild cold temperatures at 3°C below the normal feeding temperature and were subjected to acute cold stress (ACS) at 10°C on d 50 at 7 am for 6 h, 12 h, and 24 h. We determined the expression levels of toll-like receptors (TLRs), cytokines and avian ß-defencins (AvBDs), encoding genes in thymus of broilers at 22, 36, 43, and 50 d of age, and the serum ACTH and cortisol (CORT) levels at 50 d of age. At D22 and D36, the mRNA expression levels of TLRs and AvBDs genes in CS groups were generally significantly decreased (P < 0.05). The lowest expression levels were found in birds submitted to intermittent and mild cold stimulation training for 5 h (CS5 group) on d 22 and 36 of development (P < 0.05). At D43 and D49 after IMCS, mRNA expression levels of most TLRs and AvBDs were significantly lower than those in CC group (P < 0.05), and that mRNA expression levels of all TLRs and most AvBDs in CS5 group had the same change trend with age as those in CC group (P > 0.05). At D22 and D36, mRNA expression levels of different cytokines in each CS groups were different (P < 0.05). mRNA expression levels of IL-2, IL-4, IL-6, IL-8, IL-17, and IFN-α all reached the highest values in the CS5 group at D36 (P < 0.05). The levels of ACTH and CORT in all IMCS-treated birds changed in varying degrees after ACS, but there was no significant change in CS5 group (P > 0.05). Collectively, different cold stimulation schemes could modulate thymus immune function of broilers by maintaining homeostasis and enhancing cold resistance. In particular, the optimal cold adaptation scheme was at 3°C below the conventional feeding temperature for 5 h.

Strength enhancement and modulus modulation in auxetic meta-biomaterials produced by selective laser melting.

Meta-biomaterials are applied to orthopedic implants to avoid stress shielding effects; however, there is no reason for the yield strength to be comparable to that of human bone. In this study, a composite unit cell was designed by combining the positive Poisson's ratio (PPR) and negative Poisson's ratio (NPR) unit cells, inspired by the second-phase strengthening theory. The purpose was to increase the strength while maintaining the elastic modulus. All structures were successfully fabricated from Ti-6Al-4V via selective laser melting. The relative density is between 0.08 and 0.24, which falls within the optimal range for bone growth. Mechanical tests indicated that the center of the inclined rod fractured in a stepwise fracture mode, which was consistent with the predictions of the Johnson-Cook model. The elastic modulus ranged from 0.652 ± 0.016 to 5.172 ± 0.021 GPa, and the yield strength varied from 10.62 ± 0.112 to 87.158 ± 2.215 MPa. An improved Gibson-Ashby law was proposed to facilitate the design of gradient structures. When the re-entrant angle was 40°, a hybrid body-centered cubic NPR structure was formed, resulting in a significant improvement in the mechanical properties. Importantly, the yield strength of the proposed composite structures increased by 43.23%, and the compression strength increased by 44.70% under the same elastic modulus. The strengthening mechanism has been proven to apply to other bending-dominated structures. Overall, this imparts unprecedented mechanical performance to auxetic meta-biomaterials and provides insights into improving the reported porous structures. STATEMENT OF SIGNIFICANCE: Auxetic meta-biomaterials exhibit auxetic properties that can improve the contact between the bone-implant interface and reduce the risk of aseptic failure. To avoid the stress shielding effect, the elastic modulus has traditionally been decreased by increasing the porosity. However, the strength is simultaneously reduced. Therefore, a composite unit cell was proposed to increase strength rather than modulus by combining the positive and negative Poisson's ratio unit cells, inspired by the second-phase strengthening theory. We observed a 43.23% increase in the yield strength of the composite structure without increasing the elastic modulus. This strengthening mechanism has been proven to apply to other bending-dominated structures. Our approach provides insights into improving other bending-dominated structures and broadening their applications for bone implantation.

Exosomal Vaccine Loading T Cell Epitope Peptides of SARS-CoV-2 Induces Robust CD8+ T Cell Response in HLA-A Transgenic Mice.

Purpose: Current vaccines for the SARS-CoV-2 virus mainly induce neutralizing antibodies but overlook the T cell responses. This study aims to generate an exosomal vaccine carrying T cell epitope peptides of SARS-CoV-2 for the induction of CD8+ T cell response. Methods: Thirty-one peptides presented by HLA-A0201 molecule were conjugated to the DMPE-PEG-NHS molecules, and mixed with DSPE-PEG to form the peptide-PEG-lipid micelles, then fused with exosomes to generate the exosomal vaccine, followed by purification using size-exclusion chromatography and validation by Western blotting, liquid nuclear magnetic resonance (NMR) test and transmission electron microscopy. Furthermore, the exosomal vaccine was mixed with Poly (I:C) adjuvant and subcutaneously administered for three times into the hybrid mice of HLA-A0201/DR1 transgenic mice with wild-type mice. Then, the epitope-specific T cell responses were detected by ex vivo ELISPOT assay and intracellular cytokine staining. Results: The exosomal vaccine was purified from the Peak 2 fraction of FPLC and injected into the hybrid mice for three times. The IFN-γ spot forming units and the frequencies of IFN-γ+/CD8+ T cells were 10-82-fold and 13-65-fold, respectively, higher in the exosomal vaccine group compared to the Poly (I:C) control group, without visible organ toxicity. In comparison with the peptides cocktail vaccine generated in our recent work, the exosomal vaccine induced significantly stronger T cell response. Conclusion: Exosomal vaccine loading T cell epitope peptides of SARS-CoV-2 virus was initially generated without pre-modification for both peptides and exosomes, and elicited robust CD8+ T cell response in HLA-A transgenic mice.

Iron(III)-catalyzed tandem annulation of indolyl-substituted p-quinone methides with ynamides for the synthesis of cyclopenta[b]indoles.

The unique reactivity of indolyl-substituted p-QMs as a new type of two-carbon synthon has been explored for the first time in a novel iron(III)-catalyzed tandem annulation. This (2+2) annulation/retro-4π electrocyclization/imino-Nazarov cyclization cascade reaction is characterized by an unusual structural reconstruction of indolyl-substituted p-QMs, leading to an expeditious assembly of synthetically important functionalized cyclopenta[b]indoles.