Direct inhibition of tumor hypoxia response with synthetic transcriptional repressors.

Many oncogenic transcription factors (TFs) are considered to be undruggable because of their reliance on large protein-protein and protein-DNA interfaces. TFs such as hypoxia-inducible factors (HIFs) and X-box-binding protein 1 (XBP1) are induced by hypoxia and other stressors in solid tumors and bind to unfolded protein response element (UPRE) and hypoxia-induced response element (HRE) motifs to control oncogenic gene programs. Here, we report a strategy to create synthetic transcriptional repressors (STRs) that mimic the basic leucine zipper domain of XBP1 and recognize UPRE and HRE motifs. A lead molecule, STR22, binds UPRE and HRE DNA sequences with high fidelity and competes with both TFs in cells. Under hypoxia, STR22 globally suppresses HIF1α binding to HRE-containing promoters and enhancers, inhibits hypoxia-induced gene expression and blocks protumorigenic phenotypes in triple-negative breast cancer (TNBC) cells. In vivo, intratumoral and systemic STR22 treatment inhibited hypoxia-dependent gene expression, primary tumor growth and metastasis of TNBC tumors. These data validate a novel strategy to target the tumor hypoxia response through coordinated inhibition of TF-DNA binding.

[A survey on the implementation of cardiovascular surgery for congenital heart disease in China between 2017 and 2021].

Objective: To investigate the inplementation of cardiovascular surgery for congenital heart disease (CHD) in China. Methods: A cross-sectional study was carried out. The CHD cardiovascular surgery data collected by the Chinese Society of Extracorporeal Circulation from 2017 to 2021 in 31 provinces (autonomous regions/municipalities) of China were retrospectively reviewed, the implementation of CHD cardiovascular surgery in different provinces, regions, general/specialized hospitals, and different age groups (whether≤18 years old) were summarized, and the correlation analysis between the number of surgeries carried out in each province/region and the gross regional product and the number of the regional population was performed. Results: Between 2017 and 2021, the annual volume of CHD cardiovascular surgery was 77 120, 77 634, 81 161, 62 663 and 71 492, respectively, showing a decreasing trend. Meanwhile, the proportion of CHD patients aged≤18 years who underwent cardiovascular surgery also showed a downward trend, from 79.8% (61 557/77 120) in 2017 to 58.6% (41 871/71 492) in 2021 (P=0.027). The number of surgical cases varied greatly among different provinces, including 4 provinces with≥5 000 cases and 9 provinces with 2 000-5 000 cases. In the five years, the number of CHD cardiovascular surgeries in Central and East China was the largest, accounting for 41.1%-45.5% of the total surgical cases. The proportion of CHD surgery cases≤18 years old was the highest in Southwest China (69.7%-87.4%) and the lowest in Northeast China (28.2%-68.9%). Except for 2021, the number of cases carried out by each region between 2017 and 2020 was correlated with the gross regional product (r=0.929, 0.929, 0.893 and 0.964, respectively, all P<0.05) and the population (r=0.821, 0.893, 0.821 and 0.857, respectively, all P<0.05). Hospitals that performed more than 100 operations (20.5%±1.2% of the total number of hospitals) completed 86.2%±1.2% of the total number of operations in China during the 5-year period. In 2017 and 2021, the number of CHD cardiovascular surgeries preformed in children's/women's and children's specialized hospitals accounted for 24.3% (18 772/77 120) and 23.8% (17 012/71 492) of the total number of cases in China, respectively. Conclusions: From 2017 to 2021, the number of cardiovascular surgery for CHD decreases slightly, but the proportion of surgery for adult CHD patients increases significantly.There is a strong correlation between the number of CHD operations in each region and their economic development status. The scale of CHD cardiovascular surgery performed in children's hospitals/women's and children's hospitals accounts for about a quarter of the total volume in China.

[Association of waist-to-height ratio with sarcopenic obesity in hemodialysis patients with normal body mass index].

Objective: To explore the association between waist-to-height ratio (WHtR) and sarcopenic obesity (SO) in maintenance hemodialysis (MHD) patients with normal body mass index (BMI). Methods: A multicenter and cross-sectional study that included adult patients undergoing MHD was conducted in 20 hemodialysis centers from June 1st to August 30th, 2021. Body composition was evaluated by body composition monitor based on bioimpedance spectroscopy. According to the quartiles of WHtR, patients were divided into four groups: Q1, Q2, Q3 and Q4 group. The association of WHtR with SO was determined by multiple logistic regression models, stratified analyses, interactive analyses, and receiver operating characteristic (ROC) analyses, respectively. Results: A total of 2 207 MHD patients (1 341 males and 866 females) were included, and aged [M (Q1, Q3)] 57 (44, 68) years. The prevalence of SO was increased with increasing quartiles of WHtR [8.6% (46/533), 22.5% (141/628), 35.4% (215/608), and 44.3% (194/438) for Q1, Q2, Q3, and Q4 group, respectively]. Multivariate logistic regression analysis showed that WHtR was associated with SO. The association remained statistically significant even after adjusting for age, gender, dialysis vintage, BMI, biochemical indicators, and various medical histories. Compared with Q1 group, the odds ratios (OR) were 2.54 (95%CI: 1.69-3.83), 4.30 (95%CI: 2.88-6.42) and 5.18 (95%CI: 3.37-7.96) for Q2, Q3 and Q4 group, respectively. The interaction analysis showed that age, sex and history of diabetes had interactive roles in the association between WHtR and SO (all P<0.05). The association stably existed across subgroups, and it was more obvious in male patients, those with older age and without a history of diabetes（all P<0.05）. Furthermore, the cut-off value of WHtR identifying SO in male patients was 0.49, and the corresponding area under the curve (AUC) was 0.73 (95%CI: 0.70-0.75), with the sensitivity of 72.7% and specificity of 60.3%. In female patients, the cut-off value was 0.51, and the AUC was 0.68 (95%CI: 0.65-0.71), with the sensitivity of 70.1% and specificity of 57.8%. Conclusion: WHtR could be used as a simple index to evaluate the risk of SO in MHD patients with normal BMI.

Gas Chromatography-Mass Spectrometry (GC-MS) Analysis of Scaphium Affine Seed Extract and Assessment of Its Anti-hemorrhoidal Efficacy.

BACKGROUND: Seeds of plant Scaphium affine are traditionally used by the healers of "India" for the treatment of piles. OBJECTIVES: The primary objective of the study was to assess the anti-hemorrhoidal potential of the ethanolic seed extract of Scaphium affine. METHODS: After the soxhlet extraction method, the seed extract from Scaphium affine was first submitted to phytochemical standardization and then GC-MS analysis. Rats were given Croton oil and Jatropha oil to develop hemorrhoids, and Scaphium affine seed extract (ESA) was administered orally for 5 days and 3 days, respectively, at doses of 1000 and 500 mg/kg. The Rectoanal coefficient (RAC) was calculated as an inflammatory marker. The hemorrhoidal tissues were also subjected to cytokine profiling, biochemical estimation and histopathology. RESULTS: ESA demonstrated the presence of flavonoids, saponins, phytosterols, phenols, and tannins. GCMS analysis elucidated the presence of hexadecanoic acid 2 hydroxy -1,3 propane diyl ester,9 Octadecanoic acid ethyl ester, Cyclohexane 1,4 di methyl cis, Farnesol isomer,1, E-11, Z-13 octa decatriene, Stigmasterol, N-(5 ethyl -1,3,4-thiadiazol-yl) benzamide, N, N Dinitro 1,3,5,7 tetraza bicyclo 93,3,1) as major phytoconstituents. The results depicted more potent anti-hemorrhoidal activity of ESA at 1000 mg/kg, p.o., which was evident through a decrease in RAC. A significant decline in the levels of IL-1ß, IL-6, and TNF-α expression was observed, along with the restoration of altered antioxidants and enzymes. Histopathological analysis confirmed the tissue recovery as it revealed minimal inflammation and decreased dilated blood vessels in treated animals. CONCLUSION: Based on the results it can be concluded that seeds of Scaphium affine showed significant anti-hemorrhoid agents which may be attributed to their anti-inflammatory and anti-oxidant potential due to the presence of certain phytoconstituents in it. The study also supports the traditional use of seeds of Scaphium affine for the first time in the treatment of hemorrhoids.

[A study on knowledge, attitude, and vaccination behavior of herpes zoster vaccine among urban residents in selected areas of China].

Objective: To understand the knowledge, attitude, and current status of vaccination of herpes zoster vaccination among urban residents aged 25 years and above in China. Methods: In August to October 2022, a convenience sampling method was used to survey residents aged 25 years and above at 36 community centers in 9 cities across China. Questionnaires were used to collect basic information, knowledge, and attitude toward herpes zoster and its vaccination, as well as vaccination status and reasons for non-vaccination among residents. Results: A total of 2 864 urban residents were included in the study. The total score of residents' cognition of herpes zoster and its vaccine was 3.01±2.08, and the total score of their attitude was 18.25±2.76. Factors such as being male (ß=-0.45, P<0.001), older than 40-59 years (ß=-0.34, P=0.023) or ≥60 years (ß=-0.68, P<0.001), married (ß=-0.69, P=0.002) were negatively associated with knowledge score. The educational level of high school or secondary school (ß=0.44, P=0.036), college (ß=0.65, P=0.006), bachelor's degree and above (ß=1.20, P<0.001), annual net household income ≥120 000 Yuan in 2021 (ß=0.42, P=0.020), having urban employee medical insurance (ß=0.62, P=0.030), having public or commercial medical insurance (ß=0.65, P=0.033), and having a history of chickenpox (ß=0.29, P=0.025) were positively associated with knowledge scores. Being male (ß=-0.38, P=0.008) and not remembering a history of chickenpox (ß=-0.49, P=0.012) were negatively associated with attitude scores. Annual net household income in 2021 was between 40 000-80 000 Yuan (ß=0.44, P=0.032) or between 80 000-120 000 Yuan (ß=0.62, P=0.002) or ≥120 000 Yuan (ß=0.93, P<0.001), and a history of herpes zoster (ß=0.59, P=0.004) were positively associated with attitude scores. Of the 2 864 residents surveyed, only 29 (1.01%) had received the herpes zoster vaccine, with a vaccination rate of 1.70% for those aged 50 years and above, with the main reason for non-vaccination being lack of knowledge about the herpes zoster vaccine, followed by the high price. 42.67% of the population said they would consider getting the herpes zoster vaccine in the future. Conclusion: Low knowledge of herpes zoster and its vaccine, positive attitudes towards the preventive effects of herpes zoster and its vaccine, and extremely low vaccination rates among the urban population in China call for multiple measures to strengthen health education and vaccination recommendations for residents, especially for the elderly, low-education and low-income populations.

[Study on construction of c-Met specific CAR-T cells and its killing effect on non-small cell lung carcinoma].

Objective: To produce chimeric antigen receptor T cells (CAR-T) targeting human hepatocyte growth factor/c-Met (HGF/c-Met) protein and detect its cytotoxicity against non-small cell lung cancer (NSCLC) cells H1975 in vitro. Methods: The whole gene sequence of c-Met CAR containing c-Met single-chain fragment variable was synthesized and linked to lentiviral vector plasmid, plasmid electrophoresis was used to detect the correctness of target gene. HEK293 cells were transfected with plasmid and the concentrated solution of the virus particles was collected. c-Met CAR lentivirus was transfected into T cells to obtain second-generation c-Met CAR-T and the expression of CAR sequences was verified by reverse transcription-quantitative real-time polymerase chain reaction (RT-qPCR) and western blot, and the positive rate and cell subtypes of c-Met CAR-T cells were detected by flow cytometry. The positive expression of c-Met protein in NSCLC cell line H1975 was verified by flow cytometry, and the negative expression of c-Met protein in ovarian cancer cell line A2780 was selected as the control. The cytotoxicity of c-Met CAR-T to H1975 was detected by lactate dehydrogenase (LDH) cytotoxicity assay at 1∶1, 5∶1, 10∶1 and 20∶1 of effector: target cell ratio (E∶T). Enzyme-linked immunosorbent assay (ELISA) was used to detect the release of cytokines such as TNF-α, IL-2 and IFN-γ from c-Met CAR-T co-cultured with H1975. Results: The size of band was consistent with that of designed c-Met CAR, suggesting that the c-Met CAR plasmid was successfully constructed. The results of gene sequencing were consistent with the original design sequence and lentivirus was successfully constructed. CAR molecules expression in T cells infected with lentivirus was detected by western blot and RT-qPCR, which showed c-Met CAR-T were successfully constructed. Flow cytometry results showed that the infection efficiency of c-Met CAR in T cells was over 38.4%, and the proportion of CD8(+) T cells was increased after lentivirus infection. The NSCLC cell line H1975 highly expressed c-Met while ovarian cancer cell line A2780 negatively expressed c-Met. LDH cytotoxicity assay indicated that the killing efficiency was positively correlated with the E∶T, and higher than that of control group, and the killing rate reached 51.12% when the E∶T was 20∶1. ELISA results showed that c-Met CAR-T cells released more IL-2, TNF-α and IFN-γ in target cell stimulation, but there was no statistical difference between c-Met CAR-T and T cells in the non-target group. Conclusions: Human NSCLC cell H1975 expresses high level of c-Met which can be used as a target for immunotherapy. CAR-T cells targeting c-Met have been successfully produced and have high killing effect on c-Met positive NSCLC cells in vitro.

MicroRNA-214-3p Ameliorates LPS-Induced Cardiomyocyte Injury by Inhibiting Cathepsin B.

Myocardial injury is a common complication of sepsis. MicroRNA (miRNA) miR-214-3p is protective against myocardial injury caused by sepsis, but its mechanism in lipopolysaccharide (LPS)- induced cardiomyocyte injury is still unclear. An AC16 cell injury model was induced by LPS treatment. Cell Counting Kit-8 and flow cytometry assay showed decreased cell viability and increased apoptosis in LPS-treated AC16 cells. The levels of caspase- 3, Bax, atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), myosin 6 (Myh6), myosin 7 (Myh7), reactive oxygen species (ROS), and malondialdehyde (MDA) were increased in LPS-treated AC16 cells, but the levels of Bcl-2 and superoxide dismutase (SOD) were decreased. MiR-214-3p was down-regulated and cathepsin B (CTSB) was upregulated in LPS-treated AC16 cells. At the same time, miR-214-3p could target CTSB and reduce its expression. We also found that a miR-214-3p mimic or CTSB silencing could significantly reduce LPSinduced apoptosis, decrease ROS, MDA, caspase-3, and Bax and increase SOD and Bcl-2. CTSB silencing could significantly reduce ANP, BNP, Myh6, and Myh7 in LPS-treated AC16 cells. The effects of CTSB silencing were reversed by a miR-214-3p inhibitor. In summary, miR-214-3p could inhibit LPSinduced myocardial injury by targeting CTSB, which provides a new idea for myocardial damage caused by sepsis.

SARS-CoV-2 Diverges from Other Betacoronaviruses in Only Partially Activating the IRE1α/XBP1 Endoplasmic Reticulum Stress Pathway in Human Lung-Derived Cells.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has killed over 6 million individuals worldwide and continues to spread in countries where vaccines are not yet widely available or its citizens are hesitant to become vaccinated. Therefore, it is critical to unravel the molecular mechanisms that allow SARS-CoV-2 and other coronaviruses to infect and overtake the host machinery of human cells. Coronavirus replication triggers endoplasmic reticulum (ER) stress and activation of the unfolded protein response (UPR), a key host cell pathway widely believed to be essential for viral replication. We examined the master UPR sensor IRE1α kinase/RNase and its downstream transcription factor effector XBP1s, which is processed through an IRE1α-mediated mRNA splicing event, in human lung-derived cells infected with betacoronaviruses. We found that human respiratory coronavirus OC43 (HCoV-OC43), Middle East respiratory syndrome coronavirus (MERS-CoV), and murine coronavirus (MHV) all induce ER stress and strongly trigger the kinase and RNase activities of IRE1α as well as XBP1 splicing. In contrast, SARS-CoV-2 only partially activates IRE1α through autophosphorylation, but its RNase activity fails to splice XBP1. Moreover, while IRE1α was dispensable for replication in human cells for all coronaviruses tested, it was required for maximal expression of genes associated with several key cellular functions, including the interferon signaling pathway, during SARS-CoV-2 infection. Our data suggest that SARS-CoV-2 actively inhibits the RNase of autophosphorylated IRE1α, perhaps as a strategy to eliminate detection by the host immune system. IMPORTANCE SARS-CoV-2 is the third lethal respiratory coronavirus, after MERS-CoV and SARS-CoV, to emerge this century, causing millions of deaths worldwide. Other common coronaviruses such as HCoV-OC43 cause less severe respiratory disease. Thus, it is imperative to understand the similarities and differences among these viruses in how each interacts with host cells. We focused here on the inositol-requiring enzyme 1α (IRE1α) pathway, part of the host unfolded protein response to virus-induced stress. We found that while MERS-CoV and HCoV-OC43 fully activate the IRE1α kinase and RNase activities, SARS-CoV-2 only partially activates IRE1α, promoting its kinase activity but not RNase activity. Based on IRE1α-dependent gene expression changes during infection, we propose that SARS-CoV-2 prevents IRE1α RNase activation as a strategy to limit detection by the host immune system.

SARS-CoV-2 diverges from other betacoronaviruses in only partially activating the IRE1α/XBP1 ER stress pathway in human lung-derived cells.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has killed over 6 million individuals worldwide and continues to spread in countries where vaccines are not yet widely available, or its citizens are hesitant to become vaccinated. Therefore, it is critical to unravel the molecular mechanisms that allow SARS-CoV-2 and other coronaviruses to infect and overtake the host machinery of human cells. Coronavirus replication triggers endoplasmic reticulum (ER) stress and activation of the unfolded protein response (UPR), a key host cell pathway widely believed essential for viral replication. We examined the master UPR sensor IRE1α kinase/RNase and its downstream transcription factor effector XBP1s, which is processed through an IRE1α-mediated mRNA splicing event, in human lung-derived cells infected with betacoronaviruses. We found human respiratory coronavirus OC43 (HCoV-OC43), Middle East respiratory syndrome coronavirus (MERS-CoV), and murine coronavirus (MHV) all induce ER stress and strongly trigger the kinase and RNase activities of IRE1α as well as XBP1 splicing. In contrast, SARS-CoV-2 only partially activates IRE1α through autophosphorylation, but its RNase activity fails to splice XBP1. Moreover, while IRE1α was dispensable for replication in human cells for all coronaviruses tested, it was required for maximal expression of genes associated with several key cellular functions, including the interferon signaling pathway, during SARS-CoV-2 infection. Our data suggest that SARS-CoV-2 actively inhibits the RNase of autophosphorylated IRE1α, perhaps as a strategy to eliminate detection by the host immune system. IMPORTANCE: SARS-CoV-2 is the third lethal respiratory coronavirus after MERS-CoV and SARS-CoV to emerge this century, causing millions of deaths world-wide. Other common coronaviruses such as HCoV-OC43 cause less severe respiratory disease. Thus, it is imperative to understand the similarities and differences among these viruses in how each interacts with host cells. We focused here on the inositol-requiring enzyme 1α (IRE1α) pathway, part of the host unfolded protein response to virus-induced stress. We found that while MERS-CoV and HCoV-OC43 fully activate the IRE1α kinase and RNase activities, SARS-CoV-2 only partially activates IRE1α, promoting its kinase activity but not RNase activity. Based on IRE1α-dependent gene expression changes during infection, we propose that SARS-CoV-2 prevents IRE1α RNase activation as a strategy to limit detection by the host immune system.

Why are pediatric urologists unable to predict renal deterioration using urodynamics? A focused narrative review of the shortcomings of the literature.

In this focused narrative review we set out to review the current literature addressing the utilization of UDS in patients with spina bifida (SB). We specifically analyzed 6 urodynamic parameters and their roles as predictors of upper tract deterioration in pediatric SB patients. The material available did not allow a systematic analysis or the usage of metanalysis methodology, due to the predominance of small retrospective cohorts, and high heterogeneity. We identified 10 retrospective chart reviews that met our study criteria. The results of each of these papers, as well as other studies deemed relevant to the discussion, are included in our narrative review of the literature. We summarize the current literature, offer explanations for divergences in opinion, and identify future research directions and emerging solutions with a focus on machine learning.

Accelerated resolution therapy and a thematic approach to military experiences in US Special Operations Veterans.

Accelerated Resolution Therapy (ART) is an emerging therapeutic intervention that has demonstrated effectiveness in treating post-traumatic stress, anxiety and depression. The ART protocol aligns with first-line trauma-focused psychotherapies and clinical guides in the USA and UK. This review addresses previous ART research that includes members of US Special Operations Forces. Observations from that research has led to a thematic conceptualisation of trauma through ART interventions. These include three clusters of traumatic memories and several themes relevant to individual distress but not necessarily symptoms that meet diagnostic criteria for PTSD. ART represents a movement in treatment away from the symptoms, to the individuals' story. Not only the story of an event, but how that experience becomes incorporated into one's sense of identity. The themes identified (and treated with ART) appear to have broader application to the entirety of one's military experience, not just PTSD. These themes may be helpful in directing treatment and may help to focus on significant aspects of service not traditionally associated with PTSD. Theoretically, some of these areas may have protective implications in suicide.

Combination of Nitric Oxide Release and Surface Texture for Mitigating the Foreign Body Response.

The tissue response to polyurethane (PU)-coated implants employing active and/or passive FBR mitigation techniques was evaluated over a 28 day study in a diabetic swine model. Active FBR mitigation was achieved through the sustained release of nitric oxide (NO) from a mesoporous silica nanoparticle-doped PU coating. Passive FBR mitigation was achieved through the application of a foam- or fiber-based topcoat. These topcoats were designed to possess topographical features known to promote tissue integration with foam-coated implants having pore sizes of approximately 50 µm and fiber-coated implants consisting of fiber diameters of less than 1 µm. Nitric oxide-release profiles were minimally impacted by the presence of either topcoat. Inflammatory cell density and collagen density at the implant-tissue interface were assessed at 7, 14, 21, and 28 days following implantation. Nitric oxide-releasing implants had significantly lower inflammatory cell density and collagen density than non-NO-releasing controls. The presence of a topcoat did not significantly impact inflammatory cell density, though top-coated textured implants resulted in significantly lower collagen density, irrespective of NO release. Overall, coatings that combine NO release with surface texture demonstrated the greatest potential for tissue-based biomedical device applications.

Evaluation of the effects of sire and dam calving group on age at first calving in Brahman heifers.

This study evaluated the possible effects of sire and dam calving groups on age at first calving in Brahman heifers. A total of 570 heifers born between the years 2004 and 2017 were exposed as yearlings to fertile bulls through time of pregnancy determination. A calving group was determined by calculating the mean (993 d) and standard deviation (187 d) of heifer age at first calving. Heifers considered to calve early (≤899 d; calving group = 1) or late (≥1087 d; calving group = 3) were at least half a standard deviation (94 d) away from the mean. All other heifers were considered to have an intermediate age at first calving (900-1086 d; calving group = 2). Of the 570 heifers, only heifers from a dam (n = 182) with a known age at first calving and from a sire (n = 35) with 5 or more daughters were kept to determine the effect of dam calving group and the effect of sire calving group on age at first calving and calving group in daughters, resulting in a total of 284 heifers available for analysis. Variables included were dam and sire calving groups of the heifer, heifer age at first calving, heifer calving group, heifer season of birth, and heifer year of birth. Data were analyzed using the GLM procedures of SAS and proportions were tested using Chi-square. Sire calving group did affect (P < 0.01) age at first calving and calving group in heifers, but dam calving group did not affect (P > 0.10) daughter age at first calving or calving group. Analysis of dam calving group and sire calving group effects identified a year of birth effect (P < 0.01) on daughter age at first calving and calving group, whereas there was no significant season of birth effect. The proportion of daughters calving early for sire calving groups differed significantly from the expected proportion (P < 0.01), whereas the proportion of daughters calving early for dam calving groups did not differ. An effort to produce a greater proportion of Brahman heifers capable of calving early will not be effective from the dam side but may be effective from the sire side.

Fracture Diodes: Directional Asymmetry of Fracture Toughness.

Toughness describes the ability of a material to resist fracture or crack propagation. It is demonstrated here that fracture toughness of a material can be asymmetric, i.e., the resistance of a medium to a crack propagating from right to left can be significantly different from that to a crack propagating from left to right. Such asymmetry is unknown in natural materials, but we show that it can be built into artificial materials through the proper control of microstructure. This paves the way for control of crack paths and direction, where fracture-when unavoidable-can be guided through predesigned paths to minimize loss of critical components.

Local negative permittivity and topological phase transition in polar skyrmions.

Topological solitons such as magnetic skyrmions have drawn attention as stable quasi-particle-like objects. The recent discovery of polar vortices and skyrmions in ferroelectric oxide superlattices has opened up new vistas to explore topology, emergent phenomena and approaches for manipulating such features with electric fields. Using macroscopic dielectric measurements, coupled with direct scanning convergent beam electron diffraction imaging on the atomic scale, theoretical phase-field simulations and second-principles calculations, we demonstrate that polar skyrmions in (PbTiO3)n/(SrTiO3)n superlattices are distinguished by a sheath of negative permittivity at the periphery of each skyrmion. This enhances the effective dielectric permittivity compared with the individual SrTiO3 and PbTiO3 layers. Moreover, the response of these topologically protected structures to electric field and temperature shows a reversible phase transition from the skyrmion state to a trivial uniform ferroelectric state, accompanied by large tunability of the dielectric permittivity. Pulsed switching measurements show a time-dependent evolution and recovery of the skyrmion state (and macroscopic dielectric response). The interrelationship between topological and dielectric properties presents an opportunity to simultaneously manipulate both by a single, and easily controlled, stimulus, the applied electric field.

Maternal nutrient restriction alters endocrine pancreas development in fetal heifers.

Maternal nutrient restriction during pregnancy alters fetal programming, which modifies the growth and health of the offspring in postnatal life. In cattle, nutrient restriction during pregnancy can be a result of environmental or economic factors, but little is known about how it alters the physiology of the fetus and affects future reproductive or growth efficiency. This study used female monozygotic twins, produced through in vitro fertilization and embryo splitting, to determine the effect of moderate maternal nutrient restriction on fetal development. Recipient Angus cross heifers pregnant with one twin were fed a diet meeting 100% National Research Council (NRC) total energy requirements (n = 4; control), whereas recipient heifers pregnant with the second twin were fed at 70% of NRC total energy requirements (n = 4; restricted) from gestational day (GD) 158 to GD 265 in Calan gate feeders. Recipient heifers were killed at GD 265. Change in maternal metabolic body weight was greater from zero in restricted heifers than controls (P < 0.05); restricted heifers lost weight during the nutrient restriction period. There was no difference in last rib back fat or rib eye area between groups (P > 0.10). There was no difference in fetal weight, uterine weight, or total placentome weight between groups (P > 0.10). The pancreas weight was reduced in restricted fetuses compared with control fetuses (P < 0.01), but there were no other differences in fetal organ weights (P > 0.10). Plasma insulin concentrations were reduced in restricted fetuses compared with controls (P < 0.01), but there was no effect of maternal diet on plasma glucose or glucagon concentrations in the fetus (P > 0.10). Histological analyses of the fetal pancreas revealed no differences in endocrine cell number or localization. Results indicate that a modest late gestation nutritional restriction impairs development of the fetal pancreas in the cow. Additional research will be needed to determine if these developmental changes lead to altered glucose and insulin homeostasis in the adult.