Streptococcus suis Sequence Type 7 Outbreak, Sichuan, China

An outbreak of Streptococcus suis serotype 2 emerged in the summer of 2005 in Sichuan Province, and sporadic infections occurred in 4 additional provinces of China. In total, 99 S. suis strains were isolated and analyzed in this study: 88 isolates from human patients and 11 from diseased pigs. We defined 98 of 99 isolates as pulse type I by using pulsed-field gel electrophoresis analysis of SmaI-digested chromosomal DNA. Furthermore, multilocus sequence typing classified 97 of 98 members of the pulse type I in the same sequence type (ST), ST-7. Isolates of ST-7 were more toxic to peripheral blood mononuclear cells than ST-1 strains. S. suis ST-7, the causative agent, was a single-locus variant of ST-1 with increased virulence. These findings strongly suggest that ST-7 is an emerging, highly virulent S. suis clone that caused the largest S. suis outbreak ever described

Effect of refining slag compositions on its melting property and desulphurization

To investigate the feasibility of the refining slag with low fluoride, some oxides such as Al2O3, SiO2, B2O3, and Li2O were used to replace CaF2 in refining slag with the equivalent weight replacement method, and then the melting temperature and desulphurization capacity of slag were determined. The results show that the melting temperature of slag (CaF2 28 mass%) is less than 1,706 K, when CaF2 is substituted by Al2O3. This slag is able to decrease [S] in steel to less than 0.0060 mass%. In the case of substitution of CaF2 by SiO2, the melting temperature increases, while the desulphurization rate decreases. The fluxing action of B2O3 is stronger than that of CaF2, and the melting temperature decreases to 1,561 K when CaF2 is substituted by B2O3. Li2O can not only lower the melting temperature of slag but also improve the desulphurization rate

Retrospective analysis of anesthesia for deep brain electrical stimulation in movement disorders

Objective To analyze the merits and demerits, and main points of anesthetic management of different anesthesia regimens for deep brain stimulation (DBS) in movement disorders. Methods Recorded and summarized general information of 365 patients with movement disorders: 1) Local anesthesia combined with hypnoanalgesia: concentration of 1% lidocaine or 0.5% ropivacaine of local infiltration anesthesia, intravenous fentanyl (0.05-0.10 mg) and droperidol (1-2 mg) assisted sedation, analgesia. 2) Local anesthesia combined with intravenous anesthesia: local anesthesia implemented as above, in addition to intravenous fentanyl (0.05-0.10 mg), propofol 2-4 mg/(kg·h), midazolam 0.02-0.03 mg/kg. 3) Endotracheal intubation and general anesthesia: local anesthesia first, then anesthesia was induced with midazolam 0.03-0.05 mg/kg, fentanyl 2-3 μ g/kg, etomidate 0.10-0.20 mg/kg, vecuronium 0.10 mg/kg or rocuronium 0.70 mg/kg. Endotracheal intubation, was performed for mechanical ventilation after implementation. Anesthesia was maintained with continuous intravenous infusion of propofol 2-4 mg/(kg·h) and remifentanil 0.05 - 0.10 μ g/(kg·min). 4) Laryngeal mask anesthesia: firstly local anesthesia was performed as above. Then anesthesia was induced with midazolam 0.02-0.03 mg/kg, fentanyl 1-2 μg/kg, etomidate 0.10-0.20 mg/kg, vecuronium 0.10 mg/kg or rocuronium 0.70 mg/kg. Anesthesia maintenance was the same as the above. Recorded the incidence of intraoperative complications of four anesthesia regimens for deep brain stimulation. Results For local anesthesia combined with hypnoanalgesia (17.65%, 3/17) and local anesthesia combined with intravenous anesthesia (22.45%, 11/49), the incidence rate of respiratory depression was higher than the other two anesthesia (0/44, 0/255). The difference was not significant. The incidence of decreased blood pressure and increased blood pressure was higher in endotracheal intubation and general anesthesia group (29.55% and 13.64% ) than in laryngeal mask anesthesia group (8.24% and 0.78%). The difference was statistically significant (P = 0.000). Conclusion The condition of movement disorders patients is usually complex. Appropriate anesthesia regimens should be selected according to individual preoperative condition, concurrent diseases and operation requirements. Laryngeal mask anesthesia for DBS seems to be superior to other anesthesia regimens. DOI：10.3969/j.issn.1672⁃6731.2011.06.01

Preexcitation syndrome: experimental study on the electrocardiogram of antegradely conducting accessory pathway

Abstract Background Preexcitation syndrome is characterized by a dominant delta wave on the baseline electrocardiogram (ECG), resulting from the change in QRS initial vector by the accessory pathway (AP). This study is to explore the effect of ventricular preexcitation on the QRS initial, maximal and terminal vector in an experimental rabbit with preexcitation syndrome induced by programmed electrical stimulation. Methods Rabbits (n = 10) were randomized for the experimental model of ventricular preexcitation. Sensing and stimulating electrode catheters were placed in the high right atrium and along epicardial surface of atrioventricular groove of the left ventricular anterior wall, respectively. Programmed premature stimulation S2 was synchronized with P wave and utilized to stimulate the ventricle. The ECG recorded the electrical activity of the heart. As compared with the QRS complex during sinus rhythm, paced QRS was assessed regarding the initial, maximal and terminal vector. PS2 interval and PR interval were also measured and analyzed. Results Preexcitation was successfully simulated by ventricular pacing in the rabbits, including (1) Complete preexcitation: PS2 interval was less than PR interval; the difference was more than or equal to 47.00 ± 7.53 ms. (2) Incomplete preexcitation: PS2 interval was less than PR interval; the difference was less than 47.00 ± 7.53 ms. (3) Incomplete latent preexcitation: PS2 interval was more than or equal to PR interval; the difference was less than or equal to 13.00 ± 3.50 ms. (4) Complete latent preexcitation: PS2 interval was more than or equal to PR interval; the difference was more than 13.00 ± 3.50 ms. Conclusions The difference in the relative conduction velocity of the atrioventricular node versus the AP pathways determines the degree of preexcitation and different manifestation on ECG. The QRS terminal vector also reflects the ventricle preexcitation, indicating a valuable sign for the diagnosis of atypical or latent preexcitation

Hydro-plastic response of beams and stiffened panels subjected to extreme water slamming at small impact angles, Part I: An analytical solution

Water impact (slamming) is a strongly nonlinear phenomenon including significant fluid structure interactions. In the case of slamming with a small impact angle between the structure and water, the coupling between hydrodynamic pressure and the elastic responses of structures, known as hydroelasticity, matters. This has been studied extensively. However, when structures are subjected to violent water slamming in extreme sea states, large stresses may occur that exceed the material yield stress, causing large plastic flow and permanent damage. In such cases, the plastic responses of a structure will be strongly coupled with the hydrodynamic pressure, termed as hydro-plasticity. Hydro-plastic slamming has rarely been studied before. This is Part I of a two-part companion paper. The paper advances the state-of-the-art of hydro-plastic slamming by formulating, for the first time, an analytical model coupling the hydrodynamic forces and the plastic response of rectangular beams and one-way stiffened panels. The studied scenarios are flat or nearly flat water impacts, which are critical for hydro-plasticity excitation. The impact angle between the water free surface and the structure should preferably be no larger than 5°. Based on the proposed model, the governing non-dimensional parameters for hydro-plastic slamming are identified and discussed. Design curves for plate strips and stiffened panels against extreme slamming are developed. Part II-Numerical verification and analysis presents numerical verification and discussion of the analytical model by comparing with results from the multi-material Arbitrary Lagrangian Eulerian (ALE) simulations. The proposed analytical model does not require the challenging estimation of pressure history that is normally used in the design against slamming. Only the initial impact velocity is needed as the main input. The resulting non-dimensional curves may be utilized in rules and standards for the design of ships and offshore structures against extreme slamming loads

A Schedule Optimization Model on Multirunway Based on Ant Colony Algorithm

In order to make full use of the slot of runway, reduce flight delay, and ensure fairness among airlines, a schedule optimization model for arrival-departure flights is established in the paper. The total delay cost and fairness among airlines are two objective functions. The ant colony algorithm is adopted to solve this problem and the result is more efficient and reasonable when compared with FCFS (first come first served) strategy. Optimization results show that the flight delay and fair deviation are decreased by 42.22% and 38.64%, respectively. Therefore, the optimization model makes great significance in reducing flight delay and improving the fairness among all airlines

Hydro-plastic response of beams and stiffened panels subjected to extreme water slamming at small impact angles, Part II: Numerical verification and analysis

An analytical model has been proposed for the response of beams and stiffened panels subjected to extreme flat or nearly flat water impacts in Part I of the two-part companion paper. The model aims to capture the significant hydro-plastic coupling between large plastic structural deformations and the hydrodynamic pressure. Governing non-dimensional parameters for the hydro-plastic slamming phenomenon were identified and discussed. This Part II paper verifies the analytical model proposed in Part I by comparison with the hydro-plastic slamming response of beams and stiffened panels using multi-material Arbitrary Lagrangian Eulerian (ALE) methods in LS-DYNA. Numerical modelling and settings with the ALE simulations are firstly validated by comparison against drop-test experiments of a rigid wedge and of an elastic plate. Then, water entry simulations of flat plates and stiffened panels are carried out, where structural deformations go into the plastic regime. The simulated scenarios cover different plate thicknesses/cross sectional dimensions of stiffened panels, and various initial water-entry velocities. The analytical model is discussed with respect to the fluid flow, structural deflections, the pressure history and the impulse. Validity of assumptions of the analytical model is also discussed. Potential applications and limitations are indicated. The proposed design curves are well suited to be utilized in rules and standards for designing against extreme water slamming