Quantum Spin Exchange Interactions to Accelerate the Redox Kinetics in Li-S Batteries

Spin-engineering with electrocatalysts have been exploited to suppress the "shuttle effect" in Li-S batteries. Spin selection, spin-dependent electron mobility and spin potentials in activation barriers can be optimized as quantum spin exchange interactions leading to a significant reduction of the electronic repulsions in the orbitals of catalysts. Herein, we anchor the MgPc molecules on fluorinated carbon nanotubes (MgPc@FCNT), which exhibits the single active Mg sites with axial displacement. According to the density functional theory calculations, the electronic spin polarization in MgPc@FCNT not only increases the adsorption energy toward LiPSs intermediates but also facilitates the tunneling process of electron in Li-S batteries. As a result, the MgPc@FCNT provides an initial capacity of 6.1 mAh cm-2 even when the high sulfur loading is 4.5 mg cm-2, and still maintains 5.1 mAh cm-2 after 100 cycles. This work provides a new perspective to extend the main group single-atom catalysts enabling high-performance Li-S batteries.

The axial and sagittal CT values of the 7th thoracic vertebrae in screening for osteoporosis and osteopenia

AIM

To evaluate the difference in computed tomography (CT) attenuation value of different planes of the 7th thoracic vertebra and investigate the efficacy of axial and sagittal vertebral CT measurements in predicting osteoporosis.

MATERIALS AND METHODS

Patients who underwent routine chest CT and dual-energy X-ray absorptiometry (DXA) within 1 month were included in this retrospective study. The CT attenuation values of different planes were compared. Logistic regression and receiver operating characteristic (ROC) were used to analyse the difference of each plane in the diagnosis of osteoporosis.

RESULTS

The study included 1,338 patients (mean age of 61.9±11.9; 54% female). The CT attenuation values decreased successively in the normal group, osteopenia group, and osteoporosis group. The paired t-test results showed that the mid-axial measurements were greater than mid-sagittal measurements, with a mean difference of 9 HU, the difference was statistically significant (p<0.001, 95% confidence interval [CI] = 7.8-10.1). For each one-unit reduction in mid-sagittal CT attenuation value, the risk of osteopenia or osteoporosis increased by 3.6%. To distinguish osteoporosis from non-osteoporosis (osteopenia + normal), the sensitivity was 90% and the specificity was 52.4% at the mid-sagittal threshold of 113.7 HU.

CONCLUSIONS

The CT attenuation values of mid-sagittal plane have higher diagnostic efficacy than axial planes in predicting osteoporosis. For patients with a sagittal CT attenuation value of <113.7 HU in the T7, further DXA examination is warranted.

Evolution of Stabilized 1T-MoS2 by Atomic-Interface Engineering of 2H-MoS2 /Fe-Nx towards Enhanced Sodium Ion Storage

Metallic conductive 1T phase molybdenum sulfide (MoS₂ ) has been identified as promising anode for sodium ion (Na⁺ ) batteries, but its metastable feature makes it difficult to obtain and its restacking during the charge/discharge processing result in part capacity reversibility. Herein, a synergetic effect of atomic-interface engineering is employed for constructing 2H-MoS₂ layers assembled on single atomically dispersed Fe-N-C (SA Fe-N-C) anode material that boosts its reversible capacity. The work-function-driven-electron transfer occurs from SA Fe-N-C to 2H-MoS₂ via the Fe-S bonds, which enhances the adsorption of Na⁺ by 2H-MoS₂ , and lays the foundation for the sodiation process. A phase transfer from 2H to 1T/2H MoS₂ with the ferromagnetic spin-polarization of SA Fe-N-C occurs during the sodiation/desodiation process, which significantly enhances the Na⁺ storage kinetics, and thus the 1T/2H MoS₂ /SA Fe-N-C display a high electronic conductivity and a fast Na⁺ diffusion rate.

Boosting Nitrogen Reduction to Ammonia on FeN4 Sites by Atomic Spin Regulation

Understanding the relationship between the electronic state of active sites and N2 reduction reaction (NRR) performance is essential to explore efficient electrocatalysts. Herein, atomically dispersed Fe and Mo sites are designed and achieved in the form of well-defined FeN4 and MoN4 coordination in polyphthalocyanine (PPc) organic framework to investigate the influence of the spin state of FeN4 on NRR behavior. The neighboring MoN4 can regulate the spin state of Fe center in FeN4 from high-spin (dxy 2 dyz 1 dxz 1 d z 2 1 d x 2 - y 2 1 ) to medium-spin (dxy 2 dyz 2 dxz 1 d z 2 1 ), where the empty d orbitals and separate d electron favor the overlap of Fe 3d with the N 2p orbitals, more effectively activating N≡N triple bond. Theoretical modeling suggests that the NRR preferably takes place on FeN4 instead of MoN4 , and the transition of Fe spin state significantly lowers the energy barrier of the potential determining step, which is conducive to the first hydrogenation of N2 . As a result, FeMoPPc with medium-spin FeN4 exhibits 2.0 and 9.0 times higher Faradaic efficiency and 2.0 and 17.2 times higher NH3 yields for NRR than FePPc with high-spin FeN4 and MoPPc with MoN4 , respectively. These new insights may open up opportunities for exploiting efficient NRR electrocatalysts by atomically regulating the spin state of metal centers.

Recombinant lactobacillin PlnK adjusts the gut microbiome distribution in broilers

1. The heterologous expression and biological function of the Lactobacillus bacteriocin plantaricin K (PlnK) remain largely unknown. 2. In this study, PlnK was efficiently expressed in competent E. coli BL21 (used in transformation and protein expression) after 12 h, at 37°C and in 0.4 mmol/l isopropyl β- d-1-thiogalactopyranoside (IPTG). 3. The inhibitory bacterial spectrum of recombinant PlnK was investigated and indicated that levels of PlnK above 0.10 mg/ml produced an obvious inhibitory effect on gram-positive bacteria and gram-negative bacteria in vitro. 4. The effects of PlnK on intestinal immune function and the gut microbiome distribution in broilers were studied. The results revealed that, after consuming 2.50 × 10^-3 mg/ml of PlnK in water for one week, at the phylum level, the abundance of Firmicutes was increased and the abundance of Bacleroidetes was decreased. At the family level, the abundance of Lachnospiraceae, Ruminococcaceae and Streptococcaceae were significantly improved, but the abundance of Bacteroidaceae was reduced. At the genus level, the abundances of Lachnoclostridium, Streptococcus and Ruminococcaceae-UCG-013, were significantly up-regulated, and the abundance of Bacteroides was down-regulated. 5. After oral liquid intake of PlnK for one week, levels of secretory immunoglobulin A (sIgA) in the duodenal mucus were not significantly increased, but the mRNA levels of TLR3, MDA5, IFN-α, IFN-β, IFITM3 and IFITM10 in the duodenum were significantly reduced. 6. This study demonstrated that the recombinant PlnK could adjust the intestinal microbiome distribution and downregulate the IFN pathway.

Synergistic Effect of Salinized Quinone for Entrapment of Polysulfides for High-Performance Li-S Batteries

Lithium-sulfur (Li-S) batteries have attracted considerable attention in the energy storage field due to their high theoretical energy density and low price. However, the dissolution of polysulfides and the "shuttle effect" lead to serious capacity degradation, which greatly hinders the industrial application of Li-S batteries. Herein, we propose a bifunctional quinone-type salt to anchor polysulfides and suppress their dissolution for use in high-performance Li-S batteries. We find that the tetrahydroxy-1,4-benzoquinone disodium salt dimer (TBS-dimer) does not dissolve in organic electrolytes and can be generated at 400 °C. The abundant reactive keto groups and double bonds result in the TBS-dimers having numerous "hot spots" for capturing sulfur (TBS/S-400) in the three-dimensional space of the molecule. The insolubility and abundant active sites of the organic salt remarkably suppress the dissolution of lithium polysulfides. As a result, the TBS/S-400 composite delivers a capacity decay rate of only 0.023% per cycle over 600 cycles at 2 C. The use of organic salts to effectively suppress the dissolution of lithium polysulfides opens a new avenue for the practical applications of high-performance Li-S batteries.

Association between caregivers' anxiety and depression symptoms and feeding difficulties of preschool children: A cross-sectional study in rural China

PURPOSE

To investigate the prevalence of feeding difficulties in preschool children and explore the association between caregivers' anxiety and depression symptoms and preschool children's feeding difficulties.

METHODS

This cross-sectional study was conducted between June 2017 and January 2018 in rural areas of Anhui province, China. A total of 2231 preschool children and their caregivers were interviewed. Feeding difficulties of preschool children were reported by caregivers using the adapted Identification and Management of Feeding Difficulties (IMFeD) tool. Anxiety and depression symptoms of caregivers were evaluated via the Self-Rating Anxiety Scale (SAS) and the Self-Rating Depression Scale (SDS).

RESULTS

In total, 54.1% of preschool children were reported to have feeding difficulties by their caregivers. Among all children, when the caregivers had symptoms of anxiety or depression, the children had a higher risk of feeding difficulties. Specifically, for caregivers' anxiety symptoms, the odds ratios (ORs) of feeding difficulties in all children, left-behind children (LBC), and non-LBC were 1.91 (95% confidence interval [CI]: 1.42-2.57), 2.04 (95% CI: 1.34-3.09), and 1.86 (95% CI: 1.21-2.87), respectively; for caregivers' depression symptoms, the ORs of feeding difficulties in all children, LBC, and non-LBC were 1.86 (95% CI: 1.46-2.39), 1.76 (95% CI: 1.24-2.51), and 2.08 (95% CI: 1.45-2.97), respectively. In addition, when caregivers who were parents or grandparents had anxiety or depression symptoms, their children had a higher risk of feeding difficulties. Specifically, for parents and grandparents with anxiety symptoms, the ORs of feeding difficulties were 1.84 (95% CI: 1.14-2.98) and 2.17 (95% CI: 1.46-3.22), respectively; for parents and grandparents with depression symptoms, the ORs of feeding difficulties were 2.03 (95% CI: 1.40-2.95) and 1.93 (95% CI: 1.37-2.73), respectively.

CONCLUSION

Caregivers' anxiety or depression symptoms are positively associated with feeding difficulties in children.

Bubble-assisted fabrication of hollow CoMoO4 spheres for energy storage

Herein, gas bubbles generated in situ from precursors assist the rapid construction of hollow sycamore fruit-like CoMoO4 spheres (HSCSs). This bubble-assisted fabrication strategy is easy to operate, ultra-fast, low cost and post-treatment-free, showing great potential for the large-scale production of HSCSs. The growth mechanism of HSCSs is discussed to reveal the evolution process, which may be generalized to the construction of a series of hollow ternary Mo-based oxides. The obtained HSCSs exhibit a superior specific capacitance and outstanding cyclic stability when applied in supercapacitors.

Effective NaBH4-exfoliated ultrathin multilayer Co(OH)2 nanosheets arrays and sulfidation for energy storage

Facile engineering ultrathin nano structural materials is still a huge challenge for material science. Thereinto, the strategy of exfoliating shows great advantages. In this work, we develop a convenient approach to exfoliate Co(OH)₂ nanosheets into ultrathin Co(OH)₂ nanoflakes through NaBH₄-exfoliation method. Moreover, the microstructures of the Co(OH)₂ nanosheets are conveniently controlled by varying the exfoliation time. As a result, the obtained ultrathin Co(OH)₂-72 h nanosheets deliver the excellent electrochemical performance. In order to improve the energy storage properties, the obtained ultrathin Co(OH)₂ nanosheets are further modified to enhance the conductivity via sulfidation. Consequently, the synthesized Co(OH)₂-72 h/CoS₂ composites exhibit a specific capacitance of 2536 F g^-1 at 1 A g^-1, which is more outstanding than that of Co(OH)₂-72 h. What's more, the Co(OH)₂-72 h/CoS₂ composites show a capacitance retention of 83.3% after 10 000 cycles. Besides, the assembled asymmetric supercapacitor displays a power density of 482 W kg^-1 at an energy density of 36 Wh kg^-1, demonstrating a large potential for application.

Designing 3D interconnected continuous nanoporous Co/CoO core-shell nanostructure electrodes for a high-performance pseudocapacitor

A high-performance supercapacitor electrode is designed and fabricated with the 3D interconnected continuous nanoporous Co/CoO core-shell hybrid nanostructure grown on nickel foam. The Co/CoO core-shell hybrid nanostructures are obtained via a hydrothermal method, followed by high-temperature annealing in hydrogen atmosphere, and finally placed in air at 50 °C for 1 h. The Co/CoO core-shell nanostructure assembled by a conductive metal-core and a CoO shell, brings low resistance, high specific capacitance of 5.632 F cm^-2 and good capability stability (81.5% capacitance retention after 6000 cycles). An asymmetric supercapacitor device built by the Co/CoO (positive electrode) and activated carbon (negative electrode) can deliver a working voltage of 1.7 V and display a high energy density of 0.002 67 Wh cm^-2 at a power density of 0.001 62 W cm^-2, which is far superior to that of a supercapacitor at a similar power density.

Asymmetric Supercapacitor Based on Porous N-doped Carbon Derived from Pomelo Peel and NiO Arrays

A three dimensional (3D) porous framework-like N-doped carbon (PFNC) with a high specific surface area was successfully fabricated through ammonia doping and graphitization based on pomelo peel. The obtained PFNC exhibits an enhanced specific capacitance (260 F g(-1) at 1 A g(-1)) and superior cycling performance (capacitance retention of 84.2% after 10000 cycles at 10 A g(-1)) on account of numerous voids and pores which supply sufficient pathways for ion diffusion during cycling. Furthermore, a fabricated asymmetric PFNC//PFN device based on PFNC and porous flake-like NiO (PFN) arrays achieves a specific capacitance of 88.8 F g(-1) at 0.4 A g(-1) and an energy density of 27.75 Wh kg(-1) at a power density of 300 W kg(-1) and still retains 44 F g(-1) at 10 A g(-1) and 13.75 Wh kg(-1) at power density of 7500 W kg(-1). It is important that the device is able to supply two light-emitting diodes for 25 min, which demonstrates great application potential.

Bright and biocompatible AIE polymeric nanoparticles prepared from miniemulsion for fluorescence cell imaging

AIE polymeric nanoparticles with bright fluorescence, high quantum yield, low cytotoxicity, and efficient cellular uptake were prepared by miniemulsion polymerization.

Role of Glycol Chitosan-incorporated Ursolic Acid Nanoparticles in the Treatment of Osteosarcoma

Purpose: To investigate the effect of ursolic acid (UA)-incorporated glycol chitosan (GC) nanoparticles on inhibition of human osteosarcoma.Methods: U2OS and Saos-2 osteosarcoma cells were transfected with ursolic acid (UA) incorporated glycol chitosan (GC) nanoparticles. Ultraviolet (UV)  spectrophotometry was used to measure drug contents in nanoparticles at 365 nm with empty GC vehicles as blank. Bicinchoninic acid assay (BCA) method was employed to determine protein concentration. Identification of apoptosis and necrosis in osteosarcoma cells was performed by propidium iodide and FITC-annexin V reagents, respectively. FAC Scan flow cytometry was used to analyse apoptotic cells.Results: Among the range of UA concentrations tested, the minimum effective concentration was 10 μM with half inhibitory concentration IC50 of 25 μM. In U2OS cells, treatment with 10 and 25 μM UAinduced apoptosis in 5.89 ± 3.90 and 60.54 ± 5.40 % cells, respectively, compared to 2.05 ± 1.01 % cells for control. In Saos-2 cells, exposure to 10 and 25 μM UA induced apoptosis in 9.86 ± 8.89 and 47.54 ± 14.5 % cells, respectively, compared to 1.79 ± 0.23 % for control cells. Western blot analysis revealed  translocation of Bax and Bcl-2 proteins from mitochondria to cell cytosol. Increase in UA concentration  from 10 μM to 25 μM led to increase in the proportion of cells in G0/G1 phase and decrease in the number of cells in S and G2/M phases. These results confirm that UA transfection arrests cell cycle in G0/G1 phase in human osteosarcoma cell lines.Conclusion: UA transfection resulted in the inhibition of cell proliferation, Ezh2 expression inhibition, and apoptosis via mitochondrial pathway due to decrease in membrane potential and release of cytochrome C, as well as cell cycle arrest in G0/G1 phase.Keywords: Osteosarcoma, Cell cycle arrest, Palliation, Glycol chitosan, Ursolic acid

A green miniemulsion-based synthesis of polymeric aggregation-induced emission nanoparticles

A green miniemulsion-based technique for preparing polymeric aggregation-induced emission nanoparticles was described.

Soil quality indicators response to application of hydrophilic polymers to a soil from a sulfide mine

In soils impacted by mining activities a vegetal cover is required to protect the site from the erosive forces of water and wind. The success of this objective depends on plant establishment and canopy closure. Polyacryalate polymers aid the growth of crops and indigenous plants in soils from sulfide mines. Soil characteristics change as a consequence of polymer application, but indicators that pinpoint these changes have not been identified yet. Our objectives were to (1) identify the sensitive indicators of changes in soil quality following polymer application, (2) relate these with assessment based on plant growth and soil cover. A mine soil was left unamended or received a characterized polyacrylate, a polyacrylate removed from diapers, or shredded diapers. Biomass of Spergularia purpurea was measured and proportion of soil cover evaluated. Soil enzymes, microbial activity, and respiration were analyzed. Availability of potentially toxic trace elements was estimated by their concentration in shoots. Factor analysis identified three factors that accounted for 94% of the variation in parameters, and the scores separated the four treatments. The indicators with greatest communality were correlated with plant growth and soil cover. The best soil quality indicators were As and Zn in shoots, protease, β-glucosidase, and fructose-induced respiration. It seems that the most important indicators to be used to assess the restoration of sulfide mine soils are those related with bioavailability of trace elements and soil enzymatic activities.

Use of hydrophilic polymers from diapers to aid the establishment of Spergularia purpurea in a mine soil

We used hydrophilic polymers from diapers to aid the establishment of an indigenous plant (Spergularia purpurea (Persoon) G. Don fil.) in a soil from a pyrite mine. Lysimeters were filled with the mine soil with no amendment (control), with a polyacrylate polymer, with a polymer removed from diapers, and with shredded diapers. The establishment of a plant cover was faster in soil amended with polymer from diapers, and 85 days after sowing the soil was completely covered in all treatments except control. The concentrations of trace elements in plant shoots decreased in amended soil. The activities of soil acid phosphatase, beta-glucosidase, protease and cellulase were greatest in soil amended with the polyacrylate polymer or with polymer removed from diapers, while the application of shredded diapers leads to values that were in general intermediate between these treatments and unamended control. Basal- and substrate-induced respirations, and dehydrogenase were greatest in soil amended with polymers, but the presence of a plastic film and fibrous materials from shredded diapers prevented any improvement in these parameters compared with unamended soil. In the second experiment, we evaluated the risk of downward movement of polymers in columns of a sandy soil. Polymer from diapers, with or without Cu, was placed at a 10 cm-depth. Five leaching cycles with artificial rain took place and leachates were analyzed for organic matter and Cu. At the end of the experiment, the soil columns were sliced and each layer was analyzed separately. Some repacking of soil and polymer particles took place, but there was no indication that polymers moved to any great depth in soil columns.

Use of insoluble polyacrylate polymers to aid phytostabilization of mine soils: effects on plant growth and soil characteristics

We evaluated the use of polyacrylate polymers to aid phytostabilization of mine soils. In a pot experiment, perennial ryegrass was grown in a mine soil and in uncontaminated soil. Growth was stimulated in the polymer-amended mine soil compared with an unamended control, and water-extractable levels of soil Cu and Zn decreased after polymer application. In an experiment performed in six 60-cm-diameter cylinders filled with fertilized mine soil, polymers were applied to three cylinders, with the remainder used as unamended control. Total biomass produced by indigenous plant species sown in polymer-amended soil was 1.8 (Spring-Summer) or 2.4 times (Fall-Winter) greater than that of plants from unamended soil. The application of polymers to the mine soil led to the greatest activity of soil enzymes. Soil pH, biomass of Spergularia purpurea and Chaetopogon fasciculatus, and activities of protease and cellulase had large loadings on principal component (PC)1, whereas growth of Briza maxima and the activities of urease, acid phosphatase, and beta-glucosidase had large loadings on PC2. The treatments corresponding to controls were located on the negative side of PC1 and PC2. Amended treatments were on the positive side of PC2 (Spring-Summer) or on the positive side of PC1 (Fall-Winter), demonstrating differential responses of plants and soil parameters in the two growth cycles.

The osteogenic potential of pseudoarthrosis tissue and bone from human scaphoid non-unions

Scaphoid fractures have the highest prevalence of non-union in the human body, but little is known about the osteogenic potential of cells at the pseudoarthrosis. It was our goal to determine whether cells isolated from non-unions could be stimulated to differentiate into osteoblasts and produce bone in vitro. Fifteen human scaphoid non-unions were excised during surgery and bone from either side of the non-union and the fibrocartilagenous central regions were harvested. Osteoblastic populations were subcultured from these. The number of bone nodules (colonies of osteoblast cells that produced bone) from all three regions was similar to the number of nodules derived from iliac bone cultures from the same patients. Treatment of cells with rhBMP-2 resulted in a 3- to 10-fold increase in bone nodule formation in vitro from cells derived from the non-unions. These data demonstrate that cells at the pseudoarthrosis have osteogenic capability and can be stimulated by rhBMP-2, possibly increasing the ability to heal.

Scaling-up production of recombinant AAV vectors for clinical applications

Recombinant adeno-associated virus (AAV)-based vectors capable of expressing therapeutic gene products in vivo have shown significant promise for human gene therapy. A major challenge for these applications is the development of processes to enable production of large quantities of AAV vectors and purification of material that is well characterized and appropriate for parenteral administration. Several cell culture systems have been developed for AAV vector production, and a limited number of these demonstrate the potential to generate AAV vectors at concentrations compatible with cost-effective large-scale production. Vector purification protocols, in particular those based on the use of scalable column chromatography, have concurrently been developed that demonstrate the potential to provide highly purified AAV vector preparations with high yield. These advances support the potential for AAV vectors as therapeutic agents for gene therapy.

Purification of recombinant adeno-associated virus vectors by column chromatography and its performance in vivo

Recombinant adeno-associated virus (AAV) holds much promise for human gene therapy. While evidence indicates that AAV mediates long-term gene transfer in several different tissues, difficulty in preparing and purifying this viral vector in large quantities remains a major obstacle for evaluating AAV vectors in clinical trials. The current method of purification, based on sedimentation through cesium chloride, is not scaleable and yields product of insufficient quality. In this article we report a new technique for purifying AAV, using a fully closed two-column chromatography system. Yields of AAV vectors purified by this method are high, potency is increased, and the purity of column-purified preparations is substantially improved. We previously reported a novel method to generate AAV based on an AAV Rep/Cap-containing cell line (B50) and an Ad-AAV hybrid virus, which is amenable to scale-up in bioreactors. By combining the new, fully scaleable purification process we report here with the B50/hybrid production method, it would be feasible to prepare AAV vectors to the scale and purity required for clinical and potential commercial applications.

Vibrational spectroscopic studies on ion solvation of lithium perchlorate in propylene carbonate + N,N-dimethylformamide mixtures

The infrared (IR) and Raman spectra are reported for solutions of lithium perchlorate in propylene carbonate (PC), N,N-dimethylformamide (DMF) and PC + DMF mixtures. The band splittings of symmetric ring deformation for PC and O=CN deformation for DMF suggest that there is a strong interaction between lithium cations and solvent molecules. The solvent molecules have been assigned to two types, the free and complexed molecules. By a comparison of the intensity for the corresponding bands, it has been concluded that Li+ cations are preferentially solvated by DMF molecules in the LiClO4/PC-DMF solutions. This has been explained by the difference in values of donor number.

[Effect of nitrogen on water use efficiency of apple tree]

This paper studied the effect of nitrogen fertilizer on water use efficiency(WUE) and relevant parameters of two years old potted apple trees(Starkrimson/Malus hupenensis) under different soil moisture condition. The results showed that under adequate soil moisture, WUE was decreased with increasing application of nitrogen fertilizer. Nitrogen fertilizer application resulted in an increase of stomatal conductane. Consequently, the transpiration rate was increased more than photosynthetic rate did. Under soil drought, the WUE of plants applied with nitrogen fertilizer was apparently higher than that of control. The WUE value was in the order of high N > medium N > low N. The improvement of WUE was due to the increase of mesophyll capacity, which led to the promotion of photosynthesis.

Recombinant adeno-associated virus-mediated correction of lysosomal storage within the central nervous system of the adult mucopolysaccharidosis type VII mouse

The central nervous system (CNS) is a predominant site of involvement in several lysosomal storage diseases (LSDs); and for many patients, these diseases are diagnosed only after the onset of symptoms related to the progressive accumulation of macromolecules within lysosomes. The mucopolysaccharidosis type VII (MPS VII) mice are deficient for the lysosomal enzyme beta-glucuronidase and, by early adulthood, develop a significant degree of glycosaminoglycan storage within neuronal, glial, and leptomeningeal cells. Using this animal model, we investigated whether gene transfer mediated by a recombinant adeno-associated virus (rAAV) vector is capable of reversing the progression of storage lesions within the CNS. Adult MPS VII mice received intracerebral injections of 4 X 10(7) infectious units of a rAAV vector carrying the murine beta-glucuronidase (gus-s(a)) cDNA under the transcriptional direction of the cytomegalovirus immediate-early promoter and enhancer. By 1 month after vector administration, transgene-derived beta-glucuronidase was present surrounding the injection site. Enzyme levels were between 50 and 240% of that found in wild-type mice. This level of beta-glucuronidase activity was sufficient to reduce the degree of lysosomal storage. Moreover, the reduction in storage was maintained for at least 3 months post-rAAV administration. These data demonstrate that rAAV vectors can transduce the diseased CNS of MPS VII mice and mediate levels of transgene expression necessary for a therapeutic response. Thus, rAAV vectors are potential tools in the treatment of the mucopolysaccharidoses and other lysosomal storage diseases.

Gene transfer into the CNS using recombinant adeno-associated virus: analysis of vector DNA forms resulting in sustained expression

Recombinant adeno-associated virus (rAAV) vectors have shown significant promise as vehicles for in vivo gene transfer, particularly for transduction of organs composed primarily of non-dividing cells (i.e., muscle, CNS, and liver). However, the mechanistic basis for this desirable property remains unclear. To investigate the fate of rAAV genomes in mouse brain, we stereotactically injected an rAAV vector carrying the E. coli lacZ gene into the caudate of BALB/c mice and demonstrate efficient transduction of mouse brain cells that possess cellular morphology consistent with post-mitotic neurons. We observed a significant increase in beta-galactosidase expression from 5 to 56 days after injection that paralleled the disappearance of single-stranded DNA input genomes. Analysis of in vivo viral DNA forms over time out to 5 months after inoculation revealed that rAAV genomes associated with high molecular weight mouse chromosomal DNA by 14 days after injection and persisted for the length of this study. The pattern of Southern hybridization was consistent with random viral integration in predominantly head-to-tail concatameric arrays. Importantly, we also documented an additional DNA species that appears to be a monomeric episomal circular form based on nuclease sensitivity assays. These data are the first to document the existence of multiple vector DNA forms present within the adult murine brain following direct rAAV inoculation and therefore, provide insight into the molecular events that ultimately result in long-term rAAV mediated transgene expression.

Satellite DNA hypomethylation vs. overall genomic hypomethylation in ovarian epithelial tumors of different malignant potential

Rearrangements in heterochromatin in the vicinity of the centromeres of chromosomes 1 and 16 are frequent in many types of cancer, including ovarian epithelial carcinomas. Satellite 2 DNA is the main sequence in the unusually long heterochromatin region adjacent to the centromere of each of these chromosomes. Rearrangements in these regions and hypomethylation of satellite 2 DNA are a characteristic feature of patients with a rare recessive genetic disease, ICF (immunodeficiency, centromeric region instability, and facial anomalies). In all normal tissues of postnatal somatic origin, satellite 2 DNA is highly methylated. We examined satellite 2 DNA methylation in ovarian tumors of different malignant potential, namely, ovarian cystadenomas, low malignant potential (LMP) tumors, and epithelial carcinomas. Most of the carcinomas and LMP tumors exhibited hypomethylation in satellite 2 DNA of both chromosomes 1 and 16. A comparison of methylation of these sequences in the three types of ovarian neoplasms demonstrated that there was a statistically significant correlation between the extent of this satellite DNA hypomethylation and the degree of malignancy (P<0.01). Also, there was a statistically significant association (P<0.005) between genome-wide hypomethylation and undermethylation of satellite 2 DNA among these 17 tumors. In addition, we found abnormal hypomethylation of satellite alpha DNA in the centromere of chromosome 1 in many of these tumors. Our findings are consistent with the hypothesis that one of the ways that genome-wide hypomethylation facilitates tumor development is that it often includes satellite hypomethylation which might predispose cells to structural and numerical chromosomal aberrations. Several of the proteins that bind to pericentromeric heterochromatin are known to be sensitive to the methylation status of their target sequences and so could be among the sensors for detecting abnormal demethylation and mediating effects on chromosome structure and stability.

Adeno-associated virus-mediated gene transfer to the brain: duration and modulation of expression

Adeno-associated virus (AAV) is a promising vector for central nervous system (CNS) gene transfer, but a number of issues must be addressed if AAV is to be used for widespread delivery throughout the CNS. Our aim was to test the effect of dose, route of delivery, and hydroxyurea treatment on brain expression of beta-galactosidase activity after cerebral inoculation with an rAAV-lacZ vector (rAAV-beta-gal). We also wished to test whether an immune response appeared against the vector and the transgene product. We found in BALB/c mice that beta-Gal expression increased during the first 2 months after inoculation, then decreased slightly by 4 months, and continued out to 6, 12, and 15 months in single animals. Cerebral injection produced localized beta-Gal expression that did not diffuse to other regions despite a fivefold increase in injection volume. Intraventricular injection resulted in negligible transduction. Antibodies to AAV capsid protein and beta-Gal appeared at low levels at 2 and 4 months, but correlated poorly with beta-Gal expression and did not prevent readministration of rAAV-beta-gal. Hydroxyurea treatment did not result in increased transduction in vivo. We conclude that our study confirms rAAV vectors as having considerable potential for CNS gene transfer; however, several important problems must be addressed if this vector system is to be used for long-term transduction of the entire brain. Sustained, regulatable expression will be needed if rAAV is to be used in the treatment of chronic CNS disease. The difficulty in delivering AAV to diverse regions of the brain is an important problem that must be overcome if these vectors are to be used for anything beyond localized transduction.

[Relationship between urinary albumin excretion and blood vessel lesion in non-insulin-dependent diabetics]

To search the relationships between urinary albumin excretion and blood vessel lesion in non-insulin-dependent diabetics, we compared the differences of blood-lipid, blood pressure, coronary heart disease and retina disease between 58 patients. The group with microalbuminuria had significantly lower concentration of apolipoprotein A, and apolipoprotein A1/apolipoprotein B100 than that of the group with normal albuminuria, but there was no significant change in concentrations of trigly cerides, total cholesterol, high density lipoprotein, and apolipoprotein B100. Coronary heart disease and retina disease were significantly increased in group with microalbuminuria. There was negative correlation with apolipoprotein A1 and value of apolipoprotein A1/apolipoprotein B100, but positive correlation with systolic blood pressure by linear regression analysis for urinary albumin excretion.

High-titer adeno-associated viral vectors from a Rep/Cap cell line and hybrid shuttle virus

Adeno-associated virus (AAV) is a potential vector for in vivo gene therapy. A critical analysis of its utility has been hampered by methods of production that are inefficient, difficult to scale up, and that often generate substantial quantities of replication-competent AAV. We describe a novel method for producing AAV that addresses these problems. A cell line, called B50, was created by stably transfecting into HeLa cells a rep/cap-containing plasmid utilizing endogenous AAV promoters. Production of AAV occurs in a two-step process. B50 is infected with an adenovirus defective in E2b, to induce Rep and Cap expression and provide helper functions, followed by a hybrid virus in which the AAV vector is cloned in the E1 region of a replication-defective adenovirus. This results in a 100-fold amplification and rescue of the AAV genome, leading to a high yield of recombinant AAV that is free of replication-competent AAV. Intramuscular injection of vector encoding erythropoietin into skeletal muscle of mice resulted in supraphysiologic levels of hormone in serum that was sustained and caused polycythemia. This method of AAV production should be useful in scaling up for studies in large animals, including humans.

Separate and variably shaped chromosome arm domains are disclosed by chromosome arm painting in human cell nuclei

Fluorescence in situ hybridization (FISH) with microdissection probes from human chromosomes 3 and 6 was applied to visualize arm and subregional band domains in human amniotic fluid cell nuclei. Confocal laser scanning microscopy and quantitative three-dimensional image analysis showed a pronounced variability of p- and q-arm domain arrangements and shapes. Apparent intermingling of neighbouring arm domains was limited to the domain surface. Three-dimensional distance measurements with pter and qter probes supported a high variability of chromosome territory folding.

Actin isoform utilization during differentiation and remodeling of BC3H1 myogenic cells

Mouse BC3H1 myogenic cells and a bi-functional chemical cross linking reagent were utilized to investigate the polymerization of newly-synthesized vascular smooth muscle (alpha-actin) and non-muscle (beta- and gamma-actin) actin monomers into native F-actin filament structures during myogenesis. Two actin dimer species were identified by SDS-PAGE analysis of phenylenebismaleimide-cross linked fractions of BC3H1 myoblasts and myocytes. P-dimer was derived from the F-actin-enriched, detergent-insoluble cytoskeleton. Pulse-chase analysis revealed that D-dimer initially was associated with the cytoskeleton but then accumulated in the soluble fraction of lysed muscle cells that contained a non-filamentous or aggregated actin pool. Immunoblot analysis indicated that non-muscle and smooth muscle actins were capable of forming both types of dimer. However, induction of smooth muscle alpha-actin in developing myoblasts coincided with an increase in D-dimer level which may facilitate actin stress fiber assembly. Smooth muscle alpha-actin was rapidly utilized in differentiating myoblasts to assemble extraction-resistant F-actin filaments in the cytoskeleton whereas non-muscle beta- and gamma-actin filaments were more readily dissociated from the cytoskeleton by an extraction buffer containing ATP and EGTA. The data indicate that cytoarchitectural remodeling in developing BC3H1 myogenic cells is accompanied by selective actin isoform utilization that effectively segregates multiple isoactins into different sub-cellular domains and/or supramolecular entities.

[Quantitative analysis of phoxim and cypermethrin using wide bore capillary column gas chromatography]

A compound pesticide, 20% P-C emulsion, consisting of 18.5% phoxim and 1.5% cypermethrin pesticides and other accessory agents is especially effective in controlling and killing boll worms. For its quality control some difficulties were encountered. In this paper we propose a simple and practical method for GC analysis of the product by use of a short wide bore capillary column (HP-1, 5m x 0.53mm x 2.65microm), high carrier gas flow rate and high-speed temperature programming etc.. Content analysis of efficient composition of "20% P-C emulsion" was completed under the chromatographic conditions using methyl parathion as an internal standard. Coefficient of variation of phoxim and cypermethrin were 0.67% and 1.0% respectively.

Cancer mortality among silicotics in China's metallurgical industry

BACKGROUND

We conducted a retrospective cohort study of lung cancer among silicotics in China's metallurgical industries. The study cohort consisted of 4372 male silicotics diagnosed and alive before 1 January 1980. The follow-up period was 1 January 1980 to 31 December 1989.

RESULTS

Standardized mortality ratios (SMR) of all deaths, all cancers, chronic bronchopneumonia, pneumonia and pulmonary heart disease, and pulmonary tuberculosis showed statistically significant excesses. The SMR for lung cancer for the total cohort was 237 (P < 0.01). When the total study cohort was divided into various categories by occupation (including iron ore mining, ore-sintering, refractory brick manufacturing, iron and steel smelting, and steel casting), significant excess lung cancer risk was observed among silicotics in all categories (SMR > 200, P < 0.01) except for casting (SMR = 157, P > 0.05). Excess lung cancer was not related to years since diagnosis of silicosis or years of exposure to silica. There was more than twofold excess lung cancer risk among both smoking (SMR = 257, P < 0.01) and non-smoking silicotics (SMR = 209, P < 0.01). Silicosis increased the risk of lung cancer.

[Flavonol glycosides of Sonchus arvensis L]

Two flavone glycoside compounds were isolated from Sonchus arvensis by means of chemical and spectroscopic analysis. They were identified as quercetin-3-O-alpha-L-rhamnoside and kaempferol-3, 7-alpha-L-dirhamnoside.

Comparison of trained and untrained observers using subjective and objective measures of imaging performance

RATIONALE AND OBJECTIVES

We compared subjective and objective measures of imaging performance using variations of Rose- and Burger-type low-contrast phantoms with trained (radiology residents) and untrained (graduate students) observers.

METHODS

With one phantom variant, observers indicated the total number of objects seen when test objects were presented in a regular pattern (subjective). With the second phantom variant, observers stated whether a low-contrast disk was present in each locale, thereby permitting the true-positive fraction and false-positive fraction to be determined (objective).

RESULTS

The untrained-observer group had a significantly lower imaging performance than the trained observer group in subjective tests. These differences were not found on objective tests. For the trained-observer group, similar contrast levels were required in subjective and objective tests to yield a 50% rate of detection.

CONCLUSION

Trained observers are superior subjects compared with untrained observers for assessing imaging performance using subjective low-contrast phantoms. In experiments using phantoms that allowed objective testing, both groups of observers yield similar results.

Surveillance and care of four Chinese hemophiliacs with human immunodeficiency virus (HIV) infection

Four Chinese hemophiliacs with HIV infection have been followed up in Zhejiang Province since 1985. A plan for optimal care of HIV seropositive patients was proposed, including surveillance and care; clinical follow-up and preventive education of asymptomatic HIV seropositive patients; keeping the disease confidential so as not to stir up unnecessary social unease; propaganda and health education about acquired immunodeficiency syndrome (AIDS); treatment with traditional Chinese medicines; and regular surveillance of family members and medical personnel. This plan is regarded as feasible and effective for the prevention and control of AIDS in China.

[Observation on enhanced adhesion to dentin by amino acid]

An amino acid was adopted to pretreat the surface of dentin. The bond strength between GP adhesive and dentin mediated by the amino acid was enhanced after the pretreatment. Furthermore, the longer the stored time of extracted tooth was, the better the effect of adhesion was. This pretreatment will benefit the adhesive restoration for dead tooth or low activity tooth clinically.

Epstein-Barr virus DNA in nasopharyngeal biopsies

The Epstein-Barr virus (EBV) has been closely associated with the undifferentiated form of nasopharyngeal carcinoma (NPC), which is particularly common in the high risk area in southeast China. We have examined 37 nasopharyngeal biopsies from patients within this high risk area, including 31 cases of undifferentiated NPC and 6 cases of patients with nasopharyngitis, for the presence of EBV DNA. We found that 26 of 31 biopsies from NPC patients were EBV DNA positive; 3 of the 6 biopsies from patients diagnosed with nasopharyngitis were also EBV DNA positive. Southern blot analysis of the DNAs obtained from the EBV genome positive biopsies, digested with EcoRI, showed that all preparations from the NPC tumors had only one band corresponding to the EcoRI A fragment when a BamHI W fragment was used as a probe. However, one tumor had an additional band with a molecular weight larger than EcoRI A. The presence of this novel band could indicate the integration of viral DNA into host cellular DNA. DNA from the same biopsies were restricted with BamHI and PstI restriction enzymes. The data obtained from these experiments suggest that the EBV genomes in both the NPC tumor biopsies and biopsies from nasopharyngitis patients obtained from an endemic area in South China may be similar to each other and to the B95-8 EBV isolate with respect to the BamHI Y region of the EBV genome. The data also demonstrate that infection of normal nasopharyngeal epithelial cells with EBV takes place in patients with nasopharyngitis.