Energy utilization by young grass carp fed different diets

Effects of diet on food energy utilization by grass carp fed aquatic plants or formulated diets with varied lipid sources and levels are presented in three manuscripts. Significant effects of diet on food consumption, digestion, growth and muscle fatty acid (FA) composition of fingerling diploid grass carp fed aquatic macrophytes or a commercial catfish feed are reported in Chapter 1. Daily ration consumed exceded body weight in fish fed Elodea at 26°C. This resulted in excellent growth and growth was positively related to the daily intake of protein by fish fed different diets. Grass carp extensively elongated and desaturated dietary linolenic acid into long chain polyunsaturated fatty acids (PUFA). When juvenile triploid grass carp were fed Elodea, high consumption, growth rate and tissue n-3 FA levels were found. Consumption and growth of these fish, but not digestion efficiency, increased with environmental temperature (Chapter 2). In addition, a drop in growth rate coincident with decreased tissue n-3 FA levels occured at 14.4, 18.8, and 24.4°C in fish fed Elodea for 42 days and then fed catfish feed for 33 more days. Responses of fish muscle and liver FA composition to temperature were also examined. In Chapter 3, effects of dietary lipid sources and levels on energy utilization by grass carp were examined. Energy budgets for juvenile diploid grass carp fed Elodea or one of the three formulated diets with varied lipid levels were determined and compared. Growth rate, fecal energy loss and apparent heat increment were empirically related to ration size. High fecal energy losses and low metabolic cost are the general features of the energy budgets for those fish. Increasing of dietary lipid content up to about 6% resulted in better energy utilization and growth. A diet with low linoleic acid and high n-3 polyunsaturated fatty acid levels (salmon oil) inhibited appetite of fish and led to poor growth. When dietary linoleic acid supply was sufficient, addition of linolenic acid and n-3 PUFA in diets improved energy utilization and growth in diploid grass carp

Fabrication of self-healing injectable hyaluronic acid hydrogel for promoting angiogenesis

Objective·To construct a self-healing injectable hyaluronic acid (HA)-based hydrogel (HAPD-Cu) and investigate the effects of different copper ions on the properties of the hydrogel and its vasogenic efficacy to evaluate its feasibility for clinical wound healing.Methods·Bisphosphonated hyaluronic acid (HAPD) was prepared via a blue-light mediated thiol-ene click reaction between thiolated hyaluronic acid (HASH) and acrylated bisphosphonate (Ac-PD) in the presence of photoinitiator 2959. Then, HAPD was further interacted with Cu2+ through metal coordination to prepare HAPD-Cu hydrogels with different Cu2+ concentrations, i.e. HAPD-Cu1, HAPD-Cu2, HAPD-Cu3 and HAPD-Cu4. The molecular structures of HASH, Ac-PD, HAPD and HAPD-Cu were verified with 1HNMR and FTIR. Microscopic morphology of HAPD-Cu was observed under SEM. The shear-thinning and self-healing properties of HAPD-Cu were verified by rheometer. The Cu2+ release from HAPD-Cu was determined with ICP. Live-dead staining and CCK-8 assay were applied to evaluate the biocompatibility of HAPD-Cu. The in vitro vasculogenic activity of HAPD-Cu was determined by a tubule-forming assay with human umbilical vein vascular endothelial cells and the in vivo vasculogenic activity of HAPD-Cu was assessed by CD31 tissue staining. A rat wound defect model was established in vitro to evaluate its actual repair effect.Results·The preparation of the materials was demonstrated through chemical qualitative and quantitative analytical means. In vitro studies showed that all HAPD-Cu with a loose porous internal structure exhibited outstanding self-healing, injectability and degradability, with a one-week degradation cycle and abrupt release behavior, which can meet the needs of wound healing cycle. All HAPD-Cu showed good biocompatibility except HAPD-Cu4, due to its high Cu2+ concentrations. Moreover, its angiogenic effect in vitro or in vivo was enhanced with increasing Cu2+ concentrations within the permissible Cu2+ concentration range. In vitro wound model experiments also showed that the HAPD-Cu hydrogel significantly promoted wound healing compared with the control group.Conclusion·HAPD-Cu hydrogel constructed via the metal coordination shows excellent shape plasticity, allowing the filling of defective sites in a minimally invasive form, and the release of Cu2+ greatly facilitates the establishment of early vascular networks, with giant potential for use in the repair of clinically irregular wounds

Neuron-oligodendrocyte myelination co-culture derived from embryonic rat spinal cord and cerebral cortex

An in vitro myelination model derived from rat central nervous system (CNS) remains to be established. Here, we describe a simple and reproducible myelination culture method using dissociated neuron-oligodendrocyte (OL) co-cultures from either the embryonic day 16 (E16) rat spinal cord or cerebral cortex. The dissociated cells are plated directly on poly-L-lysine-coated cover slips and maintained in a modified myelination medium that supports both OL and neuron differentiation. The spinal cord derived OL progenitor cells develop quickly into myelin basic protein (MBP)+ mature OLs and start to myelinate axons around 17 days in vitro (DIV17). Myelination reaches its peak around six weeks (DIV40) and the typical nodes of Ranvier are revealed by paranodal proteins Caspr and juxaparanodal protein Kv1.2 immunoreactivity. Electron microscopy (EM) shows typical myelination cytoarchitecture and synaptic organization. In contrast, the cortical-derived co-culture requires triiodothyronine (T3) in the culture medium for myelination. Finally, either hypomyelination and/or demyelination can be induced by exposing proinflammatory cytokines or demyelinating agents to the co-culture, suggesting the feasibility of this modified in vitro myelination model for myelin-deficit investigation

Spatial Analysis of the Human Immunodeficiency Virus Epidemic among Men Who Have Sex with Men in China, 2006–2015

Background: Studies have shown a recent upsurge in human immunodeficiency virus (HIV) burden among men who have sex with men (MSM) in China, especially in urban areas. For intervention planning and resource allocation, spatial analyses of HIV/AIDS case-clusters were required to identify epidemic foci and trends among MSM in China. Methods: Information regarding MSM recorded as HIV/AIDS cases during 2006-2015 were extracted from the National Case Reporting System. Demographic trends were determined through Cochran-Armitage trend tests. Distribution of case-clusters was examined using spatial autocorrelation. Spatial-temporal scan was used to detect disease clustering. Spatial correlations between cases and socioenvironmental factors were determined by spatial regression. Results: Between 2006 and 2015, in China, 120 371 HIV/AIDS cases were identified among MSM. Newly identified HIV/AIDS cases among self-reported MSM increased from 487 cases in 2006 to >30 000 cases in 2015. Among those HIV/AIDS cases recorded during 2006-2015, 47.0% were 20-29 years old and 24.9% were aged 30-39 years. Based on clusters of HIV/AIDS cases identified through spatial analysis, the epidemic was concentrated among MSM in large cities. Spatial-temporal clusters contained municipalities, provincial capitals, and main cities such as Beijing, Shanghai, Chongqing, Chengdu, and Guangzhou. Spatial regression analysis showed that sociodemographic indicators such as population density, per capita gross domestic product, and number of county-level medical institutions had statistically significant positive correlations with HIV/AIDS among MSM. Conclusions: Assorted spatial analyses revealed an increasingly concentrated HIV epidemic among young MSM in Chinese cities, calling for targeted health education and intensive interventions at an early age

Spin-glass ground state in a triangular-lattice compound YbZnGaO4_4

We report on comprehensive results identifying the ground state of a triangular-lattice structured YbZnGaO$_4$ to be spin glass, including no long-range magnetic order, prominent broad excitation continua, and absence of magnetic thermal conductivity. More crucially, from the ultralow-temperature a.c. susceptibility measurements, we unambiguously observe frequency-dependent peaks around 0.1 K, indicating the spin-glass ground state. We suggest this conclusion to hold also for its sister compound YbMgGaO$_4$, which is confirmed by the observation of spin freezing at low temperatures. We consider disorder and frustration to be the main driving force for the spin-glass phase.Comment: Version as accepted to PR