[Research on Temporal and Spatial Evolution of Reheating Double-Pulse Laser-Induced Plasma].

In order to investigate the emission enhancement mechanisms of reheating Double Pulse Laser-Induced Breakdown Spectroscopy (DP-LIBS), single pulse LIBS (SP-LIBS) and reheating DP-LIBS were carried out on an alloy steel sample respectively. The plasma emission was collected by an Echelle spectrometer with high resolution, while the plasma structure was monitored via fast-photography. The temporal and spatial evolutio ns of the plasma generated by SP-LIBS and reheating DP-LIBS were being studied. It is found that the plasma temperature in reheating DP-LIBS was higher than that of SP-LIBS, and there was a turning point for the decay rate of plasma temperature in reheating DP-LIBS when the delay time was equal to the interpulse time of DP-LIBS. Moreover, the inte nsity of the plasma image was increased by reheating DP-LIBS, and the height and width of the central region of the plasma were increased about 23.5% and 15.1% respectively. The results of spatial distribution showed that the intensity of Fe II and N I lines in the plasma were obviously enhanced by reheating DP-LIBS when the distance from the sample surface was larger than 0.6 mm. While the intensity enhancement for Fe I lines were little, even in some positio ns the intensity of Fe I lines decreased. The plasma temperature of double-pulse configuration was about 2 000 K higher than that of SP-LIBS, and a larger hot region in the plasma was generated. It is evidenced that the emission enhancement mechanisms in reheating DP-LIBS is that the second laser pulse re-excited the plasma induced by the first laser pulse, and the higher plasma temperature resulted from the re-exciting process.

A comparative study of the therapeutic effect between long and short intramedullary nails in the treatment of intertrochanteric femur fractures in the elderly.

PURPOSE: To compare the clinical effects of long vs. short intramedullary nails in the treatment of intertrochanteric fractures in old patients more than 65 years old. METHODS: A retrospective analysis of 178 cases of intertrochanteric fractures of the femur (AO type A1 and A2) in the elderly was conducted from January 2008 to December 2013. There were 85 males (47.8%) and 93 females (52.2%) with the age of 65e89 (70.2±10.8) years. The patients were treated by closed reduction and long or short intramedullary nail (Gamma 3) fixation. The length of short nail was 180 mm and that for long nail was 320e360 mm. The general data of patients, operation time, intraoperative blood loss, length of hospital stay, preoperative hemoglobin level, blood transfusion rate, postoperative periprosthetic fractures, infections, complications, etc were carefully recorded. RESULTS: There were 76 cases (42.7%) in the long intramedullary nail group and 102 cases (57.3%) in the short nail group. All the cases were followed up for 12e48 (21.3±6.8) months, during which there were 21 deaths (11.8%), mean (13.8±6.9) months after operation. The intraoperative blood loss was (90.7±50.6) ml in short nail group, greatly less than that in long nail group (127.8±85.9) ml (p=0.004). The short nail group also had a significantly shorter operation time (43.5 min±12.3 min vs. 58.5 min±20.3 min, p=0.002) and lower rate of postoperative transfusion (42.3% vs. 56.7%, p=0.041). But the length of hospital stay showed no big differences. After operation, in each group there was 1 case of periprosthetic fracture with a total incidence of 1.1%, 1.3% in long nail group and 0.9% in short nail group. At the end of the follow-up, all patients achieved bony union. The average healing time of the long nail group was (6.5±3.1) months, and the short nail group was (6.8±3.7) months, revealing no significant differences (p=0.09). Postoperative complications showed no great differences either. CONCLUSION: Both the intramedullary long and short nail fixation has a good clinical effect in treating intertrochanteric femur fractures in the elderly. They showed no significant difference in terms of therapeutic effect, hospital stay and postoperative complications. The incidence of periprosthetic fractures treated by either length of nails was low. But short intramedullary nailing can obviously decrease the intraoperative blood loss, operation time and postoperative blood transfusion.

Identification of heavy metal sources in the reclaimed farmland soils of the pearl river estuary in China using a multivariate geostatistical approach.

Heavy metals in the reclaimed farmland soils of the Pearl River Estuary in China have attracted much attention because of the health risk posed to local residents. The identification of heavy metal sources in these soils is necessary to reduce their health risk. Reclaimed farmland soil samples were collected from 144 sites in the Pearl River Estuary and the contents of heavy metals (Cd, Pb, Cr, Ni, Cu, and Zn) were determined. All these heavy metals showed concentrations substantially higher than their background values, indicating possible anthropogenic pollution. The results of a multivariate geostatistical method demonstrate that grouped Cd, Cr, and Cu were mainly controlled by chemical fertilizers. Grouped Pb and Zn were the most severely impacted by atmospheric deposition from Guangzhou and Foshan, and Ni was primarily impacted by electroplating factories' wastewater discharge.

[Research on algorithm for self-absorption correction based on multi-particles LIBS spectra].

In order to overcome the influence of self-absorption on quantitative analysis, the optimizing process of very fast simulated annealing algorithm was studied. According to basic theory of plasma emission spectrum, a new algorithm for self-absorpton correction based on multi-particles spectra was proposed, and the algorithm flowchart was given. With the self-absorption correction algorithm mentioned above, the spectra of refining slag and blast furnace slag were corrected. The effect of self-ab sorption correction on the quantitative analysis results was analyzed based on calibration free method. Comparison of Boltzmann plots before and after self-absorption correction indicated that the plasma temperatures calculated with spectra after self-absorption correction tended to be uniform, and remained stable around 11,600 K. The Boltzmann plots constructed with plasma spectra of the same particle after self-absorption correction indicated that the intercepts were almost the same except for one group data. With calibration free method and spectra after self-absorption correction, the contents of components in slag were analyzed. For refining slag, quantitative analysis precision of MgO was low. If ignoring the existence of MgO, the relative errors of quantitative analysis results of CaO, Al2 O3 and SiOs were much smaller. For blast furnace slag in which the content of MgO was 8.49%, the relative error of quantitative analysis result of Al2 O3 was 2.38%, which was the smallest. And the relative error of quantitative analysis result of MgO was 28.27%, which was still the biggest.

[A multivariate nonlinear model for quantitative analysis in laser-induced breakdown spectroscopy].

Most quantitative models used in laser-induced breakdown spectroscopy (LIBS) are based on the hypothesis that laser-induced plasma approaches the state of local thermal equilibrium (LTE). However, the local equilibrium is possible only at a specific time segment during the evolution. As the populations of each energy level does not follow Boltzmann distribution in non-LTE condition, those quantitative models using single spectral line would be inaccurate. A multivariate nonlinear model, in which the LTE is not required, was proposed in this article to reduce the signal fluctuation and improve the accuracy of quantitative analysis. This multivariate nonlinear model was compared with the internal calibration model which is based on the LTE condition. The content of Mn in steel samples was determined by using the two models, respectively. A minor error and a minor relative standard deviation (RSD) were observed in multivariate nonlinear model. This result demonstrates that multivariate nonlinear model can improve measurement accuracy and repeatability.

Coaxial radiography guided puncture technique for percutaneous transforaminal endoscopic lumbar discectomy: A randomized control trial.

BACKGROUND: The coaxial radiography-guided puncture technique (CR-PT) is a novel technique for endoscopic lumbar discectomy. As the X-ray beam and the puncturing needle are maintained in a parallel and coaxial direction, the X-ray beam can be used to guide the trajectory angle, facilitating the choice of the puncture site and providing real-time guidance. This puncture technique offers numerous advantages over the conventional anterior-posterior and lateral radiography-guided puncture technique (AP-PT), especially in cases of herniated lumbar discs with a hypertrophied transverse process or articular process, high iliac crest, and narrowed intervertebral foramen. AIM: To confirm whether CR-PT is a superior approach to percutaneous transforaminal endoscopic lumbar discectomy compared to AP-PT. METHODS: In this parallel, controlled, randomized clinical trial, herniated lumbar disc patients appointed to receive percutaneous endoscopic lumbar discectomy treatment were recruited from the Pain Management Department of the Affiliated Hospital of Xuzhou Medical University and Nantong Hospital of Traditional Chinese Medicine. Sixty-five participants were enrolled and divided into either a CR-PT group or an AP-PT group. The CR-PT group underwent CR-PT, and the AP-PT group underwent AP-PT. The number of fluoroscopies during puncturing, puncture duration (min), surgery duration (min), VAS score during puncturing, and puncture success rate were recorded. RESULTS: Sixty-five participants were included, with 31 participants in the CR-PT group and 34 in the AP-PT group. One participant in the AP-PT group dropped out due to unsuccessful puncturing. The number of fluoroscopies [median (P25, P75)] was 12 (11, 14) in the CR-PT group vs 16 (12, 23) in the AP-PT group, while the puncture duration (mean ± SD) was 20.42 ± 5.78 vs 25.06 ± 5.46, respectively. The VAS score was 3 (2, 4) in the CR-PT group vs 3 (3, 4) in the AP-PT group. Further subgroup analysis was performed, considering only the participants with L5/S1 segment herniation: 9 patients underwent CR-PT, and 9 underwent AP-PT. The number of fluoroscopies was 11.56 ± 0.88 vs 25.22 ± 5.33; the puncture duration was 13.89 ± 1.45 vs 28.89 ± 3.76; the surgery duration was 105 (99.5, 120) vs 149 (125, 157.5); and the VAS score was 2.11 ± 0.93 vs 3.89 ± 0.6, respectively. All the above outcomes demonstrated statistical significance (P < 0.05), favoring the CR-PT treatment. CONCLUSION: CR-PT is a novel and effective technique. As opposed to conventional AP-PT, this technique significantly improves puncture accuracy, shortens puncture time and operation time, and reduces pain intensity during puncturing.

Daptomycin and linezolid for severe methicillin-resistant Staphylococcus aureus psoas abscess and bacteremia: A case report and review of the literature.

BACKGROUND: Vancomycin remains a first-line treatment drug as per the treatment guidelines for methicillin-resistant Staphylococcus aureus (MRSA) bacteremia. However, a number of gram-positive cocci have developed resistance to several drugs, including glycopeptides. Therefore, there is an urgent need for effective and innovative antibacterial drugs to treat patients with infections caused by drug-resistant bacteria. CASE SUMMARY: A 24-year-old male was admitted to hospital owing to lumbago, fever, and hematuria. Computed tomography (CT) results showed an abscess in the psoas major muscle of the patient. Repeated abscess drainage and blood culture suggested MRSA, and vancomycin was initiated. However, after day 10, CT scans showed abscesses in the lungs and legs of the patient. Therefore, treatment was switched to daptomycin. Linezolid was also added considering inflammation in the lungs. After 10 d of the dual-drug anti-MRSA treatment, culture of the abscess drainage turned negative for MRSA. On day 28, the patient was discharged without any complications. CONCLUSION: This case indicates that daptomycin combined with linezolid is an effective remedy for bacteremia caused by MRSA with pulmonary complications.

Interaction of humic substances and hematite: FTIR study.

The present work extended the knowledge on the binding and complexation of humic substances( humic acid or fulvic acid) and hematite by Fourier transform infrared spectroscopy( FTIR) . The FTIR data gained gave the consist evidences by two different sampling preparation methods that the interaction mechanism between humic substances and hematite was mainly conform to the ligand-exchange involving carboxylic functional groups of humic substances and the surfaces sites of hematite. The present method, although associated with some uncertainties, provided an opportunity to increase the knowledge in this field.