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BACKGROUND: Spectral intensity drift is a frequent issue in analytical processes, especially in long time excitation scanning for large size metal materials, which can significantly adversely impact the accuracy and stability of analysis results. Spectral intensity drift correction is the process of preprocessing spectral data using mathematical algorithms in order to facilitate the subsequent qualitative and quantitative analysis of spectra, especially in combination with stoichiometric methods. Up to now, spectral intensity drift correction within prolonged excitation has not been reported yet. RESULTS: We propose an intensity drift correction method for element content of large-size samples using the Spark Mapping Analysis for Large Samples (SMALS) technique. By considering the row-by-row and column-by-column mapping modes of the SMALS, this includes curve fitting baseline correction for in-row and in-column correction, as well as total average value correction for inter-row and inter-column correction. The final measurement values are derived by coupling rows with columns. The careful implementation of correction steps can enhance baseline correction performance, effectively reducing measurement errors a drift errors. Application of this method to characterize the cross and longitudinal sections of an oversized steel billet indicates high agreement with composition distribution obtained by micro-beam X-ray fluorescence (µ-XRF). The corrected longitudinal and cross-sectional data also exhibit strong alignment. Comparison of statistical analysis results pre- and post-correction demonstrates significant improvements in the clarity of elements segregation pattern. SIGNIFICANCE: This intensity drift correction method not only enhances the spectral quality but also improves the accuracy and robustness of quantitative and qualitative spectral analysis. This study contributes to establishing a robust foundation for component characterization of large-size metal materials using the SMALS technique. The novel spectral intensity correction method shows theoretical significance and practical value for large-scale, long-duration excitation scanning analysis.
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Controlled trials assessing quadratus lumborum block (QLB) for post-operative analgesia in hip surgery are scarce. This study aimed to compare ultrasound-guided QLB and lumbar plexus block (LPB) for clinical efficacy in hip arthroscopy. Patients undergoing hip arthroscopy in Beijing Jishuitan Hospital in January-June 2019 were randomized to the lumbar plexus (L) and quadratus lumborum (Q) groups (n = 25/group). After either ultrasound-guided block for 30 min, both groups were prepared for surgery after muscle strength measurement in the affected limbs. Opioid doses for patient-controlled analgesia (PCA), visual analog scale (VAS) scores in the resting and active states, upon leaving the post-anesthesia care unit (PACU), and at 2-48 h post-surgery were recorded, and post-operative complications were also recorded. Muscle strength in the affected limbs was significantly higher in the Q group compared with the L group (4.0 versus 2.0, P < 0.001). VAS scores were similar in both groups post-surgery (P > 0.05). One patient had epidural spread in the L group, with no other complications. Compared with ultrasound-guided LPB, ultrasound-guided QLB provides similar and good post-operative analgesia after hip arthroscopy, with less impact on muscle strength and fewer complications. These results should be confirmed in larger trials.
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Elements segregation has a significant impact on the performance of steel products and becomes more serious with the increase of products size. Many studies have been carried out on segregation in solidification. None of the studies on the quantitative analysis of segregation evaluation for the full surface of large-size metal components. In this paper the elements segregation degree (Ds) is used for large size metal component analysis for the first time corresponds to the specification of permissible variations for the final product composition. The permissible variations are able to constrain the upper limit of the segregation degree. Based on the data of non-alloy steel and low alloy steel, alloy steel, stainless steel and heat-resistant steel in ASTM (American Society for Testing and Materials) A29/A29 M and GB/T 222, the correlation between upper and lower permission variation to element content was established and the regression formula was obtained respectively. Each element content was corresponding to a specified permission limit. The segregation degree of steel products was easily evaluated by the formula precisely. The 95% prediction interval was utilized as the upper and lower variation line to evaluate the segregation degree of large-size sample. The method was successfully applied in the full-scale mapping of longitudinal section of the high-speed train wheel by Original Position Analysis for Large Samples (OPA-LS) technique. The negative and positive Ds of Al in high-speed train wheel were over DS(MAX) and the limit specified by GB/T 222, which indicated the Al segregation should be controlled.
Asunto(s)
Metales , Acero Inoxidable , Aleaciones , Metales/análisisRESUMEN
OBJECTIVE: To investigate the postoperative analgesic effect of ultrasound-guided quadratus lumborum block (QLB) in patients undergoing arthroscopic hip surgery. METHODS: Patients who were scheduled to undergo elective arthroscopic hip surgery were randomly assigned to the QLB (Q) or control (C) group (n = 40 each). After general anesthesia induction, unilateral QLB was performed under ultrasound guidance in the Q group. The amount of opioid use via patient-controlled analgesia (PCA) and the resting and movement pain visual analog scale (VAS) scores when the patient left the postanesthesia care unit (PACU) and 4, 8, 12, and 24 hours after surgery were recorded. Postoperative complications were recorded for both groups. RESULTS: At 24 hours post-surgery, opioid consumption amounts via PCA (48.4 [48.1-48.6] mL) in the Q group were significantly lower compared with the C group (52.0 [51.0-53.8] mL). A significant reduction in opioid consumption was observed between the two groups at each time point. Resting and movement VAS scores at each time point were significantly lower in the Q compared with the C group. CONCLUSIONS: Hip arthroscopy patients who received QLB and general anesthesia in combination had less pain and a lower opioid requirement within 24 hours postoperatively.