Low threshold 2nd-order random lasing of a fiber laser with a half-opened cavity.

In this paper, we reported the realization of 2nd-order random lasing in a half-opened fiber cavity, which is formed by a FBG with central wavelength at the 1st-order Raman Stokes wavelength and a single-mode fiber (SMF) performing as a random distributed feedback mirror. Using this proposed method, the threshold of 1st-order (2nd-order) random lasing is reduced to 0.7 (2.0) W, which is nearly 2 times lower than that observed in a completely-opened cavity.

[Reproduction of a rat model of disseminated intravascular coagulation accompanied by multiple organ injuries].

OBJECTIVE: To reproduce a rat model of disseminated intravascular coagulation (DIC) accompanied by multiple organ dysfunction syndrome (MODS) induced by endotoxin. METHODS: Twenty-four healthy Wistar rats were randomly divided into four groups: control group, low dosage lipopolysaccharide (LPS) group, middle dosage LPS group, and high dosage LPS group (each n=6). Rats of each group were given different dosages of normal saline (1.4 ml/kg, 2.8 ml/kg), low dosages LPS [1.4 mg/kg (56 microg/kg), 2.8 ml/kg (112 microg/kg)], middle dosages LPS [1.4 mg/kg(98 microg/kg), 2.8 ml/kg (196 microg/kg)] and high dosages LPS [1.4 ml/kg (196 microg/kg), 2.8 ml/kg (392 microg/kg)] respectively twice 12 hours apart through femoral vein intubation injection. Blood platelet (PLT) count, coagulation function, D-dimer, fibrinogen (Fbg), antithrombin III (AT-III) blood glucose (Glu), biochemistry indexes including aminotransferase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) were determined before and after LPS challenge, and histopathologic changes of lung, liver and kidney were observed 4 hours after the second injection. RESULTS: The rats in high dosage LPS group died 4 hours later, and the rats in low and middle dosage LPS groups survived after double LPS challenge. The results of blood PLT, D-dimer, Fbg, Glu, AST, ALT, ALP, LDH, coagulation function of activated partial thromboplastin time, prothrombin time and level of anti-thrombin III in middle dosage LPS group were significantly different compared with those of control group (P<0.05 or P<0.01). Obvious changes in histopathology were found in major organs such as lung, kidney and liver. CONCLUSION: Double intravenous LPS challenge (98 microg/kg and 196 microg/kg) in rats can reproduce a rat model with DIC accompanied by multiple organ injuries.

[Treatment effects of antithrombin-III on coagulation abnormalities in rats with endotoxaemia].

OBJECTIVE: To study the treatment effects of antithrombin-III (AT-III) on coagulation abnormalities in rats with endotoxaemia. METHODS: Twenty-four Wistar rats were randomly divided into control group, coagulation abnormality group and AT-III group (each n=8). Endotoxaemia coagulopathy model was reproduced by intravenous injection of lipopolysaccharide (LPS) in two doses of 1.4 ml/kg (100 microg) and 2.8 ml/kg (200 microg) 12 hours apart. In the AT-III group, AT-III 25 U/kg was given intravenously 1 hour after second injection of LPS. The changes in blood platelet (PLT) count, activated partial thromboplastin time (APTT), prothrombin time (PT), D-dimer (DD), AT-III activity, fibrinogen (FI), alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) were determined 3 hours later. RESULTS: Levels of PLT, FI and AT-III in coagulation abnormality group were lowered compared with control group (all P<0.01), while APTT, DD, PT, ALT, AST, ALP and LDH were increased (all P<0.01). All indexes were significantly improved in AT-III group, the values were close to those of normal control group (all P>0.05), and the differences were significant when compared with those of coagulation abnormality group (all P<0.01). Pathological changes of the lung, kidney and liver tissues were lighter in AT-III group than those of coagulation abnormality group. CONCLUSION: These findings indicate that AT-III can be used to treat disseminated intravascular coagulation (DIC) in rats with endotoxaemia. Preventive use of AT-III in rats with endotoxaemia is therapeutically effective.