Process optimization of magnetic grinding TC4 titanium alloy with elastic magnetic pole grinding head

Magnetic grinding has the characteristics of conformal machining. However, when a small grinding head is used to magnetically grind a workpiece with a large twist, the difference in the gap between the grinding head at different positions of the workpiece poses a challenge to the magnetic grinding process. In order to improve the surface quality of magnetic grinding and further reduce the influence of the gap difference between the grinding head and the workpiece on the surface roughness, an elastic magnetic pole grinding head with polyurethane elastomer as the magnetic pole carrier was designed, and its magnetic field simulation analysis and verification were carried out. In the experiment, the self-made diamond magnetic abrasive was used to compare the grinding performance of the polyurethane elastic magnetic pole grinding head and the ordinary magnetic pole grinding head under different machining gaps. The influence of the process parameters such as spindle speed, feed rate and abrasive particle size on the surface roughness of the workpiece was studied experimentally. The experimental results show that under the same process parameters, the processing performance of the polyurethane elastic magnetic pole grinding head is better than that of the ordinary magnetic pole grinding head under different machining gaps. Using polyurethane elastic grinding head, when the spindle speed is 800 r/min, the machining gap is 2.0 mm, the feed speed is 5 mm/min, and the abrasive particle size is 62 to 90 μm, the magnetic grinding effect is the best. After 12 minutes of grinding, the surface roughness Ra of TC4 titanium alloy can be reduced from the initial 0.350 μm to 0.039 μm, and the surface roughness improvement rate reaches 89%. The results verify the effect of the elasticity and profiling characteristics of the polyurethane elastic layer on the quality of the machined surface

High-Throughput Metabolic Soft-Spot Identification in Liver Microsomes by LC/UV/MS: Application of a Single Variable Incubation Time Approach

CYP-mediated fast metabolism may lead to poor bioavailability, fast drug clearance and significant drug interaction. Thus, metabolic stability screening in human liver microsomes (HLM) followed by metabolic soft-spot identification (MSSID) is routinely conducted in drug discovery. Liver microsomal incubations of testing compounds with fixed single or multiple incubation time(s) and quantitative and qualitative analysis of metabolites using high-resolution mass spectrometry are routinely employed in MSSID assays. The major objective of this study was to develop and validate a simple, effective, and high-throughput assay for determining metabolic soft-spots of testing compounds in liver microsomes using a single variable incubation time and LC/UV/MS. Model compounds (verapamil, dextromethorphan, buspirone, mirtazapine, saquinavir, midazolam, amodiaquine) were incubated at 3 or 5 µM with HLM for a single variable incubation time between 1 and 60 min based on predetermined metabolic stability data. As a result, disappearances of the parents were around 20–40%, and only one or a few primary metabolites were generated as major metabolite(s) without notable formation of secondary metabolites. The unique metabolite profiles generated from the optimal incubation conditions enabled LC/UV to perform direct quantitative estimation for identifying major metabolites. Consequently, structural characterization by LC/MS focused on one or a few major primary metabolite(s) rather than many metabolites including secondary metabolites. Furthermore, generic data-dependent acquisition methods were utilized to enable Q-TOF and Qtrap to continuously record full MS and MS/MS spectral data of major metabolites for post-acquisition data-mining and interpretation. Results from analyzing metabolic soft-spots of the seven model compounds demonstrated that the novel MSSID assay can substantially simplify metabolic soft-spot identification and is well suited for high-throughput analysis in lead optimization

High-energy extracorporeal shock wave therapy for nontraumatic osteonecrosis of the femoral head

Abstract Background Nontraumatic osteonecrosis of the femoral head (ONFH) is treated with a series of methods. High-energy extracorporeal shock wave therapy (ESWT) is an option with promising mid-term outcomes. The objective of this study was to determine the long-term outcomes of ESWT for ONFH. Methods Fifty-three hips in 39 consecutive patients were treated with ESWT in our hospital between January 2005 and July 2006. Forty-four hips in 31 patients with stage I–III nontraumatic ONFH, according to the Association Research Circulation Osseous (ARCO) system, were reviewed in the current retrospective study. The visual analog pain scale (VAS), Harris hip score, radiography, and magnetic resonance imaging were used to estimate treatment results. The progression of ONFH was evaluated by imaging examination and clinical outcomes. The results were classified as clinical success (no progression of hip symptoms) and imaging success (no progression of stage or substage on radiography and MRI). Results The mean follow-up duration was 130.6 months (range, 121 to 138 months). The mean VAS decreased from 3.8 before ESWT to 2.2 points at the 10-year follow-up (p < 0.001). The mean Harris hip score improved from 77.4 before ESWT to 86.9 points at the 10-year follow-up. The clinical success rates were 87.5% in ARCO stage I patients, 71.4% in ARCO stage II patients, and 75.0% in ARCO stage III patients. Imaging success was observed in all stage I hips, 64.3% of stage II hips, and 12.5% of stage III hips. Seventeen hips showed progression of the ARCO stage/substage on imaging examination. Eight hips showed femoral head collapse at the 10-year follow-up. Four hips in ARCO stage III and one hip in ARCO stage II were treated with total hip arthroplasty during the follow-up. Three were performed 1 year after ESWT, one at 2 years, and one at 5 years. Conclusions The results of the current study indicated that ESWT is an effective treatment method for nontraumatic ONFH, resulting in pain relief and function restoration, especially for patients with ARCO stage I–II ONFH

Evaluation of white cell count and differential in synovial fluid for diagnosing infections after total hip or knee arthroplasty.

BACKGROUND: The accuracy of synovial fluid (SF) white cell count (WCC) and polymorphonuclear (PMN) cell evaluation for predicting prosthetic joint infection (PJI) at the total hip arthroplasty (THA) or total knee arthroplasty (TKA) site is unknown. Therefore, we performed a meta-analysis to summarize the diagnostic validity of SF-WCC and SF-PMN for diagnosing PJI. METHODS: The MEDLINE, EMBASE, and OVID databases were searched for studies that had evaluated the diagnostic validity of SF-WCC and SF-PMN between January 1990 and May 2013. Meta-analysis methods were used to pool sensitivity, specificity, diagnostic odd ratios (DORs), the area under the receiver-operating characteristic curve (AUC), positive likelihood ratios (PLR), negative likelihood ratios (NLR), and post-test probability. We also conducted heterogeneity, publication bias, subgroup, and meta-regression analyses. RESULTS: Fifteen articles (15 SF-WCC and 14 SF-PMN) that included a total of 2787 patients fulfilled the inclusion criteria and were considered for analysis. The pooled sensitivity and specificity for PJI detection was 0.88 (95% confidence intervals [CI], 0.81-0.93) and 0.93 (95% CI, 0.88-0.96) for SF-WCC and 0.90 (95% CI, 0.84-0.93) and 0.88 (95% CI, 0.83-0.92) for SF-PMN, respectively. The AUC was 0.96 for SF-WCC and 0.95 for SF-PMN. PLR and NLR were 13.3 and 0.13 for SF-WCC, and 7.6 and 0.12 for SF-PMN, respectively. There was no evidence of publication bias. Low-clinical-scenario (pre-test probability, 20%) post-test probabilities were 3% for both negative SF-WCC and SF-PMN results. The subgroup analyses indicated that the sensitivity/specificity of THA were 0.73/0.96 for SF-WCC and 0.85/0.83 for SF-PMN, whereas those of TKA were 0.90/0.91 for SF-WCC and 0.90/0.88 for SF-PMN. We also found that collection of SF-WCC preoperatively had a higher sensitivity than that obtained intraoperatively (0.91 vs. 0.77). CONCLUSIONS: SF-WCC and SF-PMN have an adequate and clinically acceptable diagnostic value for detecting PJI, particularly after TKA

Utility of Intraoperative Frozen Section in the Diagnosis of Periprosthetic Joint Infection

<div><p>Purpose</p><p>Intraoperative frozen section (FS) is an effective diagnostic test for periprosthetic joint infection (PJI). We evaluated the diagnostic characteristics of single- and multiplex-site intraoperative FS, and evaluated the results of single-site FS combined with those of C-reactive protein (CRP) level and erythrocyte sedimentation rate (ESR) for assessing PJI.</p><p>Methods</p><p>We studied 156 painful joint arthroplasties in 152 consecutive patients presenting for revision total joint arthroplasty due to PJI. Receiver operating characteristic analysis was used to determine the optimal cutoff values for CRP level, ESR, and intraoperative FS histopathology. Sensitivity, specificity, positive and negative predictive values, and accuracy of the diagnostic tests were assessed using a 2×2 table.</p><p>Results</p><p>We investigated the diagnostic utility of polymorphonuclear leukocyte number (PMN) per high-power field (HPF) on FS. Our data showed that 5 PMNs per HPF is a suitable diagnostic threshold, with a high accuracy in single- and multiplex-site FS. Five PMNs in any 1 of 5 sites had the highest sensitivity of 0.86 and a specificity of 0.96. Five PMNs in every 1 of 5 sites had greater diagnostic utility, with a specificity of 1; however, the sensitivity of this measure fell to 0.62. Five PMNs in single-site FS had a sensitivity of 0.70 and a specificity of 0.94. Five PMNs in single-site FS or CRP level ≥15 mg/L increased the sensitivity to 0.92; however, the specificity decreased to 0.79.</p><p>Conclusion</p><p>Compared with single-site FS, any 1 positive site on multiplex-site FS may improve sensitivity, while every 1 positive site on multiplex-site FS may improve specificity. Five PMNs in any 1 of 5 sites on FS has excellent utility for the diagnosis of PJI. Additional systematic large-scale studies are needed to verify this result.</p></div

Receiver operating characteristic (ROC) curve, demonstrating the polymorphonuclear leukocyte number (PMN) cutoff value of 2.4 for all patients in the cohort.

<p>*AUC, area under the curve.</p

Diagnostic test characteristics for CRP, ESR, and combined tests.

<p>CRP, C-reactive protein; ESR, erythrocyte sedimentation rate; FS, frozen section; PMNs, polymorphonuclear cells.</p