871 research outputs found

    Development and evaluation of pH-responsive single-walled carbon nanotube-doxorubicin complexes in cancer cells

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    Single-walled carbon nanotubes (SWNTs) have been identified as an efficient drug carrier. Here a controlled drug-delivery system based on SWNTs coated with doxorubicin (DOX) through hydrazone bonds was developed, because the hydrazone bond is more sensitive to tumor microenvironments than other covalent linkers. The SWNTs were firstly stabilized with polyethylene glycol (H2N-PEG-NH2). Hydrazinobenzoic acid (HBA) was then covalently attached on SWNTs via carbodiimide-activated coupling reaction to form hydrazine-modified SWNTs. The anticancer drug DOX was conjugated to the HBA segments of SWNT using hydrazine as the linker. The resulting hydrazone bonds formed between the DOX molecules and the HBA segments of SWNTs are acid cleavable, thereby providing a strong pH-responsive drug release, which may facilitate effective DOX release near the acidic tumor microenvironment and thus reduce its overall systemic toxicity. The DOX-loaded SWNTs were efficiently taken up by HepG2 tumor cells, and DOX was released intracellularly, as revealed by MTT assay and confocal microscope observations. Compared with SWNT-DOX conjugate formed by supramolecular interaction, the SWNT-HBA-DOX featured high weight loading and prolonged release of DOX, and thus improved its cytotoxicity against cancer cells. This study suggests that while SWNTs have great potential as a drug carrier, the efficient formulation strategy requires further study

    Complete genome sequence of Thermaerobacter marianensis type strain (7p75a).

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    Thermaerobacter marianensis Takai et al. 1999 is the type species of the genus Thermaerobacter, which belongs to the Clostridiales family Incertae Sedis XVII. The species is of special interest because T. marianensis is an aerobic, thermophilic marine bacterium, originally isolated from the deepest part in the western Pacific Ocean (Mariana Trench) at the depth of 10.897m. Interestingly, the taxonomic status of the genus has not been clarified until now. The genus Thermaerobacter may represent a very deep group within the Firmicutes or potentially a novel phylum. The 2,844,696 bp long genome with its 2,375 protein-coding and 60 RNA genes consists of one circular chromosome and is a part of the Genomic Encyclopedia of Bacteria and Archaea project

    Syntropic spin alignment at the interface between ferromagnetic and superconducting nitrides

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    The magnetic correlations at the superconductor/ferromagnet (S/F) interfaces play a crucial role in realizing dissipation-less spin-based logic and memory technologies, such as triplet-supercurrent spin-valves and "{\pi}" Josephson junctions. Here we report the coexistence of an induced large magnetic moment and a crypto ferromagnetic state at high-quality nitride S/F interfaces. Using polarized neutron reflectometry and d. c. SQUID measurements, we quantitatively determined the magnetization profile of S/F bilayer and confirmed the induced magnetic moment in the adjacent superconductor only exists below TC. Interestingly, the direction of the induced moment in the superconductors was unexpectedly parallel to that in the ferromagnet, which contrasts with earlier findings in S/F heterostructures based on metals or oxides. The first-principles calculations verify the observed unusual interfacial spin texture is caused by the Heisenberg direct exchange coupling through d orbital overlapping and severe charge transfer across the interfaces. Our work establishes an incisive experimental probe for understanding the magnetic proximity behavior at S/F interfaces and provides a prototype epitaxial building block for superconducting spintronics.Comment: 21 pages, 5 figures, supplementary file with 14 figure

    Strain mediated phase crossover in Ruddlesden Popper nickelates

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    Recent progress on the signatures of pressure-induced high temperature superconductivity in Ruddlesden Popper (RP) nickelates (Lan+1NinO3n+1) has attracted growing interest in both theoretical calculations and experimental efforts. The fabrication of high-quality single crystalline RP nickelate thin films is critical for possible reducing the superconducting transition pressure and advancing applications in microelectronics in the future. In this study, we report the observations of an active phase transition in RP nickelate films induced by misfit strain. We found that RP nickelate films favor the perovskite structure (n = infinite) under tensile strains, while compressive strains stabilize the La3Ni2O7 (n = 2) phase. The selection of distinct phases is governed by the strain dependent formation energy and electronic configuration. In compressively strained La3Ni2O7, we experimentally determined splitting energy is ~0.2 eV and electrons prefer to occupy in-plane orbitals. First principles calculations unveil a robust coupling between strain effects and the valence state of Ni ions in RP nickelates, suggesting a dual driving force for the inevitable phase co-existence transition in RP nickelates. Our work underscores the sensitivity of RP nickelate formation to epitaxial strain, presenting a significant challenge in fabricating pure-phase RP nickelate films. Therefore, special attention to stacking defects and grain boundaries between different RP phases is essential when discussing the pressure-induced superconductivity in RP nickelates.Comment: 29 pages, 5 figures, one supplementary material

    Traditional Chinese medicine Dingkun pill to increase fertility in women with a thin endometrium—a prospective randomized study

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    ObjectiveThe aim of this study is to optimize the treatment methods of infertility, which is suggested to be mainly caused by thin endometrium, using a special form of traditional Chinese medicine, the Dingkun pill (DKP), to increase the beneficial endometrial effect of conventional hormone/progestogen therapy.MethodsA total of 307 patients visiting our specialized gynecological endocrinology department because of infertility, which we suggested to be caused by thin endometrium [endometrial thickness (EMT) < 7 mm], were randomly assigned to the experimental group and the control group. The experimental group was treated with estradiol + sequential dydrogesterone + DKP (every day); the control group received hormonal treatment without the Chinese medicine. All patients were monitored in terms of follicle diameter, EMT, and endometrial type every 2 days from the 8th to the 10th day of the menstrual cycle until ovulation day during three menstrual cycles. Serum progesterone levels on 7–8 days after ovulation were measured, and the cumulative pregnancy rate during three menstrual cycles between the two groups was compared.ResultsEMT on ovulation day in the experimental group was significantly higher than that in the control group (7.88 vs. 7.15 mm; p < 0.001). The proportion of type A and type B endometrium in total was significantly higher in the experimental group than that in the control group (83.2% vs. 77.7%; p < 0.05). Progesterone levels were significantly higher in the experimental group than those in the control group (10.874 vs. 10.074 ng/mL; p < 0.001). The cumulative pregnancy rate, the main outcome of the study, was significantly higher in the experimental group than that in the control group (29.2% vs. 15.7%; p < 0.05).ConclusionDKP added to conventional estrogen/progestogen therapy can significantly improve EMT and luteal function in patients attending due to infertility. Because this regimen increased the cumulative pregnancy rate in our study, we conclude that DKP can be used to increase the so-called “thin endometrium infertility”

    Ovarian tissue cryopreservation in the pediatric with rare diseases- experience from China’s first and the largest ovarian tissue cryobank

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    BackgroundThere is limited information about the efficacy of ovarian tissue cryopreservation (OTC) in children. In the present study, we report eight patients with rare diseases who underwent OTC in China’s first and largest ovarian tissue cryobank.ProcedureData from girls with rare diseases who underwent OTC between September 2020 and November 2022 were retrospectively analyzed. We also compared the number of cryopreserved cortex pieces, follicle number, and AMH in those with rare diseases and age-matched children with non-rare diseases who also underwent OTC in our cryobank.ResultsThe median age of the children was 5.88 ± 3.52 (range 2-13) years old. Unilateral oophorectomy was undertaken via laparoscopy in all of the children. The diseases in the 8 patients were: 4 mucopolysaccharidoses (MPS I two cases, IVA two cases), 1 Diamond-Blackfan anemia (DBA), 1 Fanconi anemia (FA), 1 hyperimmunoglobulin E syndrome (HIES), 1 Niemann-Pick disease. The number of cryopreserved cortex pieces was 17.13 ± 6.36, and the follicle count per 2 mm biopsy was 447.38 ± 524.35. No significant difference in age, the count of cryopreserved cortex pieces, follicle number per 2 mm biopsy, and AMH level was seen between the 20 children with non-rare diseases and those with rare diseases.ConclusionsThe reports help practitioners counsel girls with rare diseases about fertility preservation. The demand for OTC in pediatrics will likely grow as a standard of care
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