Investigation of the interaction between graphene oxide and a biopolymer surface

Graphene oxide (GO) is functionalized graphene sheet. Due to its exceptional mechanical properties, GO is widely considered a promising filler material for producing nanocomposites. Biopolymers are polymers produced by living organism. They are as strong and tough as synthetic polymers, yet feature exceptional biocompatibility. The combination of GO and biopolymers, then, can yield potential novel nanocomposites. These novel materials have the potential to possess a combination of outstanding properties. They would be thin, lightweight, strong, and biocompatible. Therefore, these materials can have many applications in various fields, such as biocompatible coatings and body implants. In this project, we report an investigation of the interaction between GO and a biopolymer surface. The results of our work would provide crucial details for exploring synthesis mechanism for GO-biopolymer nanocomposites

Repeated doses of melatonin protects against focal cerebral ischemia in the rat

We studied the time window of neuroprotection against focal ischemia by a single dose or repeated doses of melatonin (MT) at 5 mg/kg. Adult male Sprague-Dawley rats (280 to 360 g) were anesthetized with sodium pentobarbital (60 mg/kg, I.P.) to undergo reversible right-sided endovascular middle cerebral artery occlusion (MCAO) for 3 hours. Arterial blood pressure, heart rate and cerebral blood flow were monitored, and rectal temperature was kept between 36.5 and 37.5 ºC throughout anesthesia. The control rats received 1 I.P. dose of the vehicle at the onset of ischemia, whereas experimental groups of rats received either 1 I.P. dose of MT at 0 or 60 minutes after onset of ischemia or 3 doses of MT at 1, 24, and 48 hours after onset of ischemia. The rats were decapitated on day 3 of MCAO, and their brains were stained with 2% triphenyltetrazolium chloride for determination of infarction. Results were compared using 2-tailed student’s t test. When compared to the relative infarct volume of 27.0±4.6% (mean±SEM; 7 rats) in the control group, a single (5 mg/kg) I.P. dose of MT did not significantly reduce the relative infarct volume (20.1±4.1% in the 0-minute group [8 rats]; 19.8±3.2% in the 60-minute group [9 rats]). Nevertheless, the relative infarct volume was significantly reduced to 13.9±3.4% (8 rats, P < 0.05) in the group which received 3 doses of MT. There was no significant difference in hemodynamic parameters among the groups. Thus, repeated doses rather than a single dose of exogenous MT protects against focal cerebral ischemia, when given 60 minutes after onset of ischemia. Supported by the CRCG Research Grant 10202138 of the University of Hong Kongpublished_or_final_versio

In vivo neuroprotection of melatonin against focal cerebral ischaemia in the rat

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Melatonin pretreatment protects against focal cerebral ischemia in the rat

Melatonin (MT) possesses many properties of an ideal neuroprotectant. In this study, the neuroprotective effects of exogenous MT were tested in a middle cerebral artery occlusion (MCAO) stroke model. Adult male Sprague-Dawley rats (280 to 360 g) were anesthetized with sodium pentobarbital (60 mg/kg, I.P.) to undergo reversible right-sided endovascular MCAO for 3 hours. Arterial blood pressure, heart rate and cerebral blood flow (CBF) were monitored, and rectal temperature was kept between 36.5 and 37.5 ºC throughout anesthesia. One I.P. dose of MT (at 1.5, 5, or 15 mg/kg) or the vehicle was given 30 minutes before onset of ischemia. The rats were decapitated on day 3 of MCAO, and their brains were stained with 2% triphenyltetrazolium chloride for determination of infarction. Results were compared using 2-tailed student’s t test. When compared to the relative infarct volume of 31.8±3.3% (mean±SEM; 16 rats) in the control group, treatment with MT reduced the relative infarct volume in a dose-dependent manner (30.5±3.2% in the 1.5 mg/kg group [17 rats]; 15.9±2.2% in the 5 mg/kg group [16 rats], P < 0.05; 21.4±3.0% in the 15 mg/kg group [15 rats], P < 0.05). There was no significant difference in heart rate, arterial blood pressure and CBF among the groups. We concluded that a single dose of MT between 5 and 15 mg/kg protects against focal cerebral ischemia, when given 30 minutes before onset of ischemia. The above doses of MT do not produce significant hemodynamic effects nor alter the CBF during ischemia and reperfusion. Supported by the CRCG Research Grant 10202138 of the University of Hong Kongpublished_or_final_versio

Production Of Cellulase And Xylanase By Indigenous Aspergillus Niger Ai-1 Via Solid Substrate Fermentation And Its Application In Deinking Of Mixed Office Waste Paper

The present work focused on the production of cellulases and xylanase using Aspergillus niger AI-1 via solid substrate fermentation and its application in enzymatic deinking of mixed office waste paper. A total of 25 out of 70 fungal isolates representing the genera of Aspergillus, Penicillium, Trichoderma, and Mucor were selected based on the hydrolysis zone observed in CMC and oat spelt agar plates. They were also selected based on their high cellulases and xylanase activity. Solid substrate fermentation was carried out using these fungal isolates and local agricultural wastes consisting of sugar cane bagasse, palm kernel cake, rice husk and wood dusts were used as substrate. Among them, 3 fungi isolates were selected based on the highest enzymes production on SSF using the mixture of sugar cane bagasse and palm kernel cake as substrate

Protective Effect of FTY720 on Several Markers of Liver Injury Induced by Concanavalin A in Mice

AbstractBackground2-Amino-2-[2-(4-octylphenyl)ethyl] propane-1,3-diol hydrochloride (FTY720) is a novel agent with protective effect on several markers of liver injury. It is a chemical substance derived by modifying myriocin from the ascomycete Isaria sinclairii. It has been reported that FTY720 is able to treat autoimmune encephalomyelitis, renal cancer, asthma, and multiple sclerosis. More potent clinical applications of FTY720 need to be investigated.ObjectiveThe aim of this study was to evaluate the protective effect of FTY720 on several markers of experimental liver injury and to investigate the possible mechanism of action.MethodsConcanavalin A (Con A) at a dose of 15 mg/kg was intravenously. injected in mice, and 10 days before the Con A challenge, 1 mg/kg, 3 mg/kg, and 6 mg/kg of FTY720 were administered to mice. The liver injury was monitored biochemically by measuring serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and tumor necrosis factor-α (TNF-α) levels. TNF-α and nuclear factor-κB (NF-κB) in liver tissue were detected by Western blot analysis.ResultsFTY720, when administered intragastrically for 10 days in mice with Con A–induced liver injury, dose-dependently reduced serum ALT and AST and TNF-α levels. The differences were statistically significant (P ≤ 0.05). It was also found that FTY720 decreases TNF-α and NF-κB protein expression in liver tissue.ConclusionsFTY720 is able to improve several markers of Con A–induced liver injury in mice, including serum ALT, serum AST, TNF-α, and NF-κB, which might be at least in part related to its ability to reduce TNF-α/NF-κB cascade activity

Production Of Cellulase And Xylanase Via Solid State Fermentation And Its Application In The Enzymatic Deinking Of Laser Printed Waste Papers.

The work deals with the production of cellulase and xylanase by local isolates via solid state fermentation SSF) processes for the application in the enzymatic deinking of laser printed wastepapers

Current Status and Outlook of Research on Emergency Drills for Public Health Emergencies

Public health emergencies are major infectious disease outbreaks, mass unexplained diseases, major food and occupational poisoning and other events that seriously affect public health that occur suddenly and cause serious damage to the public health of society. In the absence of certain preplanned preparations and experience in emergency response, the outbreak of public health emergencies always catches us off guard and poses a huge challenge and burden to public health and social safety. At present, due to the late start of the emergency management of public health emergencies, the lack of a perfect theoretical system of emergency management, the weak public awareness of emergencies, the lack of scientific emergency measures, the lack of a perfect and flexible public health emergency management system, and the lack of an advanced emergency management level of society as a whole, all of these factors have led to inefficiency, communication and a lack of experience in dealing with public health emergencies such as the new coronary pneumonia outbreak in the early stage. In this context, it is important to take a deeper look at the problems of inefficiency and poor communication in handling public health emergencies. In this context, it is important to examine the current research status of emergency drills for public health emergencies in China, investigate the typical problems, and propose a series of innovative practical strategies for emergency drills for public health emergencies, such as exploring the closed-loop management mode of emergency drills for public health emergencies and giving full play to the role of information technology as a driver of innovation, according to the current development level of China as a whole