Frustrated magnetic interactions and quenched spin fluctuations in CrAs

The discovery of pressure-induced superconductivity in helimagnets (CrAs, MnP) has attracted considerable interest in understanding the relationship between complex magnetism and unconventional superconductivity. However, the nature of the magnetism and magnetic interactions that drive the unusual double-helical magnetic order in these materials remains unclear. Here, we report neutron scattering measurements of magnetic excitations in CrAs single crystals at ambient pressure. Our experiments reveal well defined spin wave excitations up to about 150 meV with a pseudogap below 7 meV, which can be effectively described by the Heisenberg model with nearest neighbor exchange interactions. Most surprisingly, the spin excitations are largely quenched above the Neel temperature, in contrast to cuprates and iron pnictides where the spectral weight is mostly preserved in the paramagnetic state. Our results suggest that the helimagnetic order is driven by strongly frustrated exchange interactions, and that CrAs is at the verge of itinerant and correlation-induced localized states, which is therefore highly pressure-tunable and favorable for superconductivity.Comment: 6 pages, 4 figure

A pH-responsive α-helical cell penetrating peptide-mediated liposomal delivery system

Tumor-oriented nanocarrier drug delivery approaches with pH-sensitivity have been drawing considerable attentions over the years. Here we described a liposomal delivery system modified with pH-responsive cell penetrating peptide TH (TH-Lip). Conventional cell penetrating peptide (CPP)-related drug delivery tactics sometimes seemed limited due to the extensive in vivo penetration and the lack of proper selectivity of conventional CPPs. In this study, TH (AGYLLGHINLHHLAHL(Aib)HHIL-NH2), an engineered α-helical cell penetrating peptide originated from peptide TK (AGYLLGKINLKKLAKL(Aib)LLIL-NH2), was endowed pH-responsiveness after complete replacement of all lysines in the sequence of TK into histidines, and was introduced onto the surface of liposomes. Accordingly, TH-Lip could benefit from the unique property of TH, as the cell penetrating capacity of TH was concealed during the blood circulation and in normal tissues because of the neutral pH under those conditions. However, when TH-Lip reached the tumor, and as pH declined, histidines in TH peptide protonated and the surface charge of TH-Lip converted from negative to positive, initiating activated cell penetrating capacity and leading to enhanced cellular and tumor spheroid uptake. The endocytosis inhibition assay demonstrated that the endocytosis of TH-Lip was influenced by the positively charged surface of the liposomes in acidic environment and was mediated by clathrin, and the intracellular trafficking study suggested that the liposomes were mainly accumulated in endoplasmic reticulum and Golgi apparatus. After systemic administration in mice, TH-Lip could be internalized into tumor cells efficaciously. When it comes to the delivery of paclitaxel (PTX), the pH-responsiveness of TH-Lip led to strong inhibition against tumor cell growth which occurred both in vitro (under pH 6.3) and in vivo, and the tumor inhibition rate reached 86.3% on C26 tumor-bearing mice for PTX-loaded TH-Lip. Therefore, TH-Lip proved itself to be a promising pH-responsive strategy for drug delivery within acidified tumor microenvironment

The complete mitochondrial genome of Cheilinus trilobatus (Perciformes: Labridae)

Cheilinus trilobatus Lacépède, 1801 is a species of genus Cheilinus. In this study, we sequenced the complete mitochondrion genome of C. trilobatus. The mitochondrial genome was 17,292 bp, consisting of 13 protein-coding genes, 22 tRNA genes, two rRNA genes, and one non-coding control region (D-loop). The nucleotide composition was 27.31% A, 25.1% T, 17.23% G, and 30.36% C. Phylogenetic analysis suggested that C. trilobatus was closely related to Cheilinus oxycephalus. The complete mitogenome of C. trilobatus provided basic data for the genetic diversity conservation of this species

The Effects of Purple Corn Pigment on Growth Performance, Blood Biochemical Indices, Meat Quality, Muscle Amino Acids, and Fatty Acids of Growing Chickens

This study investigated the effects of dietary supplementation with different levels of purple corn pigment (PCP) on the growth performance, blood biochemical indices, meat quality, muscle amino acids, and fatty acids of growing chickens. A total of 288 (8 weeks of age) growing Chishui black-bone chickens (body weight, 940 ± 80 g; mean ± standard deviation) were randomly divided into 4 groups using a completely randomized design. The four diet groups were as follows: (1) control, basal diet; (2) treatment 1, treatment 2, and treatment 3, which were basal diet with 80, 160, and 240 mg/kg PCP, respectively. The results showed that compared with the control group, the feeding of anthocyanins significantly (p < 0.05) increased the average daily feed intake and average daily gain in chickens. Moreover, chickens receiving 80 mg/kg PCP significantly increased (p < 0.05) plasma total antioxidant capacity, superoxide dismutase, glutathione peroxidase, catalase, high-density lipoprotein cholesterol, and albumin concentrations relative to the control group. For meat quality, dietary supplementation with PCP significantly (p < 0.05) reduced the drip loss and water loss rate in breast muscle. Additionally, chickens receiving PCP tended to increase (p < 0.05) the levels of most individual amino acids, essential amino acids, and umami amino acids in the muscle. Specifically, the addition of 80 mg/kg PCP significantly improved (p < 0.05) total polyunsaturated fatty acids in chicken muscle. Accordingly, the consumption of anthocyanin-rich PCP by the growing chickens had the potential to increase the growth performance, enhance antioxidant and immune capacities, increase meat quality, and improve essential and umami amino acids as well as unsaturated fatty acids in the muscle

PEGylated Hyaluronic Acid-Modified Liposomal Delivery System with Anti-γ-Glutamylcyclotransferase siRNA for Drug-Resistant MCF-7 Breast Cancer Therapy

Human chromosome 7 open reading frame 24 has been identified as a tumor-related protein, and later it was shown to be γ-glutamylcyclotransferase (GGCT). This protein is upregulated in various types of cancer and is proved to be associated with cellular proliferation. RNA interference is an effective method to achieve highly specific gene regulation. In this study, the anti-GGCT siRNA was incorporated into a comprehensively evaluated polyethylene glycol–hyaluronic acid-modified liposomal siRNA delivery system (PEG–HA–NP) for drug-resistant MCF-7 breast cancer therapy by systemic administration. The PEG–HA–NP had a diameter of 216 nm and a zeta potential of − 17.4 mV. Transfection of anti-GGCT siRNA-loaded PEG–HA–NP could achieve effective GGCT downregulation and induce the subsequent cell cytotoxicity against MCF-7/ADR cells. Systemic administration of PEG–HA–NP at 0.35 mg/kg siRNA could retard the tumor growth and induce necrosis of tumor tissue while showing no obvious toxicity to normal tissues. Therefore, systemic administration of anti-GGCT-loaded PEG–HA–NP was proved to be a promising strategy for drug-resistant MCF-7 breast cancer therapy

Polymer–Drug Nanoparticles Combine Doxorubicin Carrier and Heparin Bioactivity Functionalities for Primary and Metastatic Cancer Treatment

Here, a biocompatible amphiphilic copolymer of low molecular weight heparin (LMWH) and doxorubicin (DOX) connected by an acid-sensitive hydrazone bond for enhanced tumor treatment efficacy and safety has been designed and tested. The conjugate combines DOX delivery with LMWH antimetastatic capabilities. After the nanoparticles reach the tumor site, the acidic tumor microenvironment triggers the breakage of the hydrazone bond releasing DOX from the nanoparticles, which results in an increase in the cellular uptake and enhanced in vivo antitumor efficacy. A 3.4-fold and 1.5-fold increase in tumor growth inhibition were observed compared to the saline-treated control group and free DOX treated group, respectively. The LMWH-based nanoparticles effectively inhibited interactions between tumor cells and platelets mediated by P-selectin reducing metastasis of cells in both in vitro and in vivo models. The improved safety and therapeutic effect of LMWW-DOX nanoparticles offers new potential for tumor therapy

Enhanced gene delivery efficiency of cationic liposomes coated with PEGylated hyaluronic acid for anti P-glycoprotein siRNA: A potential candidate for overcoming multi-drug resistance

RNA interference is an effective method to achieve highly specific gene regulation. However, the commonly used cationic liposomes have poor biocompatibility, which may lead to systematic siRNA delivery of no avail. PEGylation is a good strategy in shielding the positive charge of cationic liposomes, but the enhanced serum stability is often in company with compromised cellular uptake and endosome escape. In this study, PEG was covalently linked to negatively charged hyaluronic acid and it was used to coat the liposome-siRNA nanoparticles. The resulting PEG–HA–NP complex had a diameter of 188.6 ± 10.8 nm and a dramatically declined zeta-potential from +34.9 ± 4.0 mV to −18.2 ± 2.2 mV. Owing to the reversed surface charge, PEG–HA–NP could remain stable in fetal bovine serum (FBS) to up to 24 h. In contrast with normal PEGylation, hyaluronic acid and PEG co-modified PEG–HA–NP provided comparable cellular uptake and P-glycoprotein downregulation efficacy in MCF-7/ADR cells compared with Lipofectamine RNAiMAX and naked NP regardless of its anionic charged surface. Because of its good biocompatibility in serum, PEG–HA–NP possessed the best tumor accumulation, cellular uptake and subsequently the strongest P-glycoprotein silencing capability in tumor bearing mice compared with naked NP and HA–NP after i.v. injection, with a 34% P-glycoprotein downregulation. Therefore, PEG–HA coated liposomal complex was demonstrated to be a promising siRNA delivery system in adjusting solid tumor P-glycoprotein expression, which may become a potential carrier in reversing MDR for breast cancer therapy

Paclitaxel loaded liposomes decorated with a multifunctional tandem peptide for glioma targeting

The treatment of glioma is a great challenge because of the existence of the blood-brain barrier (BBB). In order to reduce toxicity to the normal brain tissue and achieve efficient treatment, it is also important for drugs to specifically accumulate in the glioma foci and penetrate into the tumor core after entering into the brain. In this study, a specific ligand cyclic RGD peptide was conjugated to a cell penetrating peptide R8 to develop a multifunctional peptide R8-RGD. R8-RGD increased the cellular uptake of liposomes by 2-fold and nearly 30-fold compared to separate R8 and RGD respectively, and displayed effective penetration of three-dimensional glioma spheroids and BBB model in vitro. In vivo studies showed that R8-RGD-lipo could be efficiently delivered into the brain and selectively accumulated in the glioma foci after systemic administration in C6 glioma bearing mice. When paclitaxel (PTX) was loaded in liposomes, R8-RGD-lipo could induce the strongest inhibition and apoptosis against C6 cells and finally achieved the longest survival in intracranial C6 glioma bearing mice. In conclusion, all the results indicated that the tandem peptide R8-RGD was a promising ligand possessing multi functions including BBB transporting, glioma targeting and tumor penetrating. And R8-RGD-lipo was proved to be a potential anti-glioma drug delivery system