Derivation of Two-Fluid Model Based on Onsager Principle

Using the Onsager variational principle, we study the dynamic coupling between the stress and the composition in a polymer solution. In the original derivation of the two-fluid model of Doi and Onuki the polymer stress was introduced a priori; therefore, a constitutive equation is required to close the equations. Based on our previous study of viscoelastic fluids with homogeneous composition, we start with a dumbbell model for the polymer, and derive all dynamic equations using the Onsager variational principle.     

Mintaimycins,a Group of Novel Peptide Metabolites from Micromonospora sp. C-3509

A group of peptide metabolites (1–4), designated as mintaimycins, were isolated from Micromonospora sp. C-3509. The planar structures of mintaimycins were determined by combination of mass spectrometry, 1D and 2D NMR spectroscopy, and the stereochemistry of mintaimycins were partially resolved by Marfey’s or Mosher’s method. Mintaimycins featured a central β-methylphenylalanine or phenylalanine linked at its amino group with 5-methyl-2-hexenoic acid, and at its carboxyl group with 5-hydroxy-norleucine or leucine that combined a derivative of hexanoic acid or 4-methylpentanoic acid. Mintaimycin A₁ (1), the principal component, was found to exhibit the biological activity of inducing pre-adipocyte differentiation of 3T3-L1 fibroblast cells at 10.0 μmol/L.     

Structural engineering of cathodes for improved Zn-ion batteries

Aqueous zinc-ion batteries (ZIBs) are attracting considerable attention because of their low cost,high safety and abundant anode material resources.However,the ...     

The mitochondrial unfolded protein response (UPRmt) protects against osteoarthritis

The mitochondrial unfolded protein response (UPR^mt) is a mitochondrial-to-nuclear signaling pathway that is activated to maintain mitochondrial function when there is an accumulation of misfolded proteins within mitochondria. Mitochondrial function is essential for chondrocyte homeostasis, and mitochondrial dysfunction is a characteristic of osteoarthritis (OA). However, the role of the UPR^mt in OA remains unclear. In the present study, the level of the UPR^mt was examined in primary mouse chondrocytes subjected to different stresses and in the articular cartilage of OA model mice and OA patients. The relationship between UPR^mt activation and OA progression was studied. The UPR^mt was induced in primary mouse chondrocytes subjected to diverse stresses and in the cartilage of OA mice. Enhancement of the UPR^mt with nicotinamide riboside (NR) significantly improved mitochondrial function, reduced chondrocyte death, attenuated OA pain, and ameliorated OA progression, and the protective effects decreased significantly in chondrocyte-specific Atf5 knockout (ATF5^f/fCol2a1-CreER^T2) mice. UPR^mt induction was also identified in the articular cartilage of OA patients and was associated with reduced chondrocyte death, less severe hip pain, and lower levels of inflammation in synovial fluid. These findings identify the induction of the UPR^mt in primary mouse chondrocytes exposed to pathological stresses and in the articular cartilage of OA model mice and OA patients. Enhancement of the UPR^mt ameliorates OA progression, suggesting that the UPR^mt exerts a protective effect against OA and may be a potential diagnostic and therapeutic strategy for OA.Subject terms: Apoptosis, Bone     

MicroRNA-375 is a therapeutic target for castration-resistant prostate cancer through the PTPN4/STAT3 axis

The functional role of microRNA-375 (miR-375) in the development of prostate cancer (PCa) remains controversial. Previously, we found that plasma exosomal miR-375 is significantly elevated in castration-resistant PCa (CRPC) patients compared with castration-sensitive PCa patients. Here, we aimed to determine how miR-375 modulates CRPC progression and thereafter to evaluate the therapeutic potential of human umbilical cord mesenchymal stem cell (hucMSC)-derived exosomes loaded with miR-375 antisense oligonucleotides (e-375i). We used miRNA in situ hybridization technique to evaluate miR-375 expression in PCa tissues, gain- and loss-of-function experiments to determine miR-375 function, and bioinformatic methods, dual-luciferase reporter assay, qPCR, IHC and western blotting to determine and validate the target as well as the effects of miR-375 at the molecular level. Then, e-375i complexes were assessed for their antagonizing effects against miR-375. We found that the expression of miR-375 was elevated in PCa tissues and cancer exosomes, correlating with the Gleason score. Forced expression of miR-375 enhanced the expression of EMT markers and AR but suppressed apoptosis markers, leading to enhanced proliferation, migration, invasion, and enzalutamide resistance and decreased apoptosis of PCa cells. These effects could be reversed by miR-375 silencing. Mechanistically, miR-375 directly interfered with the expression of phosphatase nonreceptor type 4 (PTPN4), which in turn stabilized phosphorylated STAT3. Application of e-375i could inhibit miR-375, upregulate PTPN4 and downregulate p-STAT3, eventually repressing the growth of PCa. Collectively, we identified a novel miR-375 target, PTPN4, that functions upstream of STAT3, and targeting miR-375 may be an alternative therapeutic for PCa, especially for CRPC with high AR levels.Subject terms: miRNAs, Prostate cancer     

Organocatalytic Enantioselective Michael Reaction of Aminomaleimides with Nitroolefins Catalyzed by Takemoto’s Catalyst

Known as electrophiles, maleimides are often used as acceptors in Michael additions to produce succinimides. However, reactions with maleimides as nucleophiles for enantioselective functionalization are only rarely performed. In this paper, a series of bifunctional Takemoto’s catalysts were used to organocatalyze the enantioselective Michael reaction of aminomaleimides with nitroolefins. The resulting products were obtained in good yields (76–86%) with up to 94% enantiomer excess (ee). The catalyst type and the substrate scope were broadened using this methodology.     

Highly Stretchable Composite Foams via Sustainable Utilization of Waste Tire Rubbers for Temperature-Dependent Electromagnetic Wave Absorption

Recently, the sustainable utilization of waste resources has become a low-cost and effective strategy to design high-performance functional materials to solve the increasingly serious environmental pollution problem. Herein, the flexible and highly stretchable polyurethane (PU) composite foams assisted by one-dimensional carbon nanotubes (CNTs) and zero-dimensional Fe₃O₄ were fabricated using waste tire rubbers (WTRs) as reinforcements during a simple self-foaming process. The collaborative introduction of conductive CNTs, magnetic Fe₃O₄, and WTRs with three-dimensional cross-linked structures enabled the construction of an efficient electronic transmission path and heterointerfaces inside the composite foam. The resulting composite foam possessed a desired minimum reflection loss (RL_min) of −47.43 dB, and also exhibited superior mechanical properties with a tensile strength of >3 MPa and multiple tensile deformation recovery abilities. In addition, increasing the temperature could significantly improve the electromagnetic wave absorption performance of the composite foam. This comprehensive composite foam derived from WTRs has shown a promising development potential for using waste materials to relieve electromagnetic pollution.     

Synthesis and Anticonvulsant Activity of γ-Aminobutyric Acid Derivatives

y-Aminobutyricacidisregardedasoneofthemaj0rinhibit0ryneur0transmittersinthemammaliancentralnervoussystem."'UnderPhysiologicalconditi0ns,y-aminobutyricacidpo0riycrossestheb1ood-brainbarrier.SoitisnoteffectivebyoraladministTation.3'4ItisIikelythatan0n-toxicderivativeofy-arninobutyricacidwhichentersthebraineasilywi1lhaveusefultheraPeuticproperties.Withthisinmind,wehavedesignedandsynthesizedl6derivativesofy-aminobubocacidwithaniminelinktoa1ip0philiccarrierinordert0facilitatethepassage0fy-aminobu…     

Ho3+掺杂对六角YMn0.8Fe0.2O3微结构和磁性质的调控

本文利用高温固相反应法合成了六角Y_1-xHo_xMn_0.8Fe_0.2O₃多晶样品,研究Ho³⁺掺杂对YMn_0.8Fe_0.2O₃微结构以及磁性质的影响。X射线衍射和拉曼测量结果显示所有样品均为单相六角结构,当Ho³⁺掺杂浓度低于0.15时,晶格常数a、c,晶胞体积及Mn—O键长均随着掺杂浓度的增加而减小。A位稀土原子位移差以及拉曼声子模式的变化表明随着Ho³⁺掺杂比例增加,A位稀土原子相对于平面的偏移减小,MnO₅双锥体倾斜角减小,B位Mn³⁺的三聚作用被削弱,Mn³⁺—O^2-—Mn³⁺间超交换作用减弱,反铁磁(AFM)序被抑制,反铁磁转变温度下降。磁性测量显示低温下Y_0.9Ho_0.1Mn_0.8Fe_0.2O₃的磁化强度显著增强,弱铁磁(WFM)序增加,归因于Ho³⁺加入后系统磁阻挫行为的降低及Ho³⁺—O^2-—Mn³⁺间自旋交换作用产生的铁磁序。这为进一步探索室温多铁性材料提供了思路。