Development of Low-Pressure He-MC-MIP-MS and Its Application for Oxygen Isotopic Analysis.

In Ar-based inductively coupled plasma mass spectrometry (MS), Ar-related interference and the low ionization capacity of the Ar-ion source prevent facile and precise determination of certain elements. To address this problem, we investigated the application of microwave-induced plasma (MIP), and we improved its ionization capacity using He as the working gas. The MIP ion source was connected to a multicollector mass spectrometry (MC-MS) apparatus to improve the accuracy and precision of the isotopic analysis. A vacuum pump was used to achieve a low pressure (200-300 Pa) at the interface. The analytical figures of merit were discussed and evaluated by measuring the oxygen isotopes in oxygen. With the application of low-pressure He-MC-MIP-MS, the degree of ionization of oxygen could be significantly improved with He plasma. The interference of oxygen from the atmosphere could also be eliminated with low-pressure plasma, and the determination precision of oxygen isotopes could be improved with the application of MC-MS. Subsequently, using this method, 16O18O/16O16O was applied as the analytical ratio to investigate the interference, sensitivity, and precision. With this constructed method, the obtained long-term producibility of δ18O was 0.16‰ (2 SD), and the measured result for oxygen was consistent with that obtained by MAT 253 within the uncertainty limit. The development of low-pressure He-MC-MIP-MS can pave the way for the accurate measurement of nonmetal isotopes and easily interfered isotopes in Ar plasma.

High-precision simultaneous measurement of 187Os, 186Os, and 184Os using 1013 Ω amplifiers and CDDs on NTIMS.

High-precision measurements of 184Os/188Os, 186Os/188Os, and 187Os/188Os ratios are significant in the fields of geochemistry and cosmochemistry. However, no high-precision measurement technique exists for simultaneously obtaining all three ratios using a static method for samples with an Os content of <1 ng or 186OsO3‾ and 187OsO3‾ ion-beam intensities of <150 mV. This greatly limits research on rare samples with small sample sizes or low Os contents, such as Lunar, Martian, or old Earth samples. This paper reports a static method, which could achieve the simultaneous measurement of 9 Faraday cups (FCs) with high-signal/noise ratio 1012 Ω amplifiers and 1013 Ω amplifiers and two compact discrete dynodes (CDDs). By analyzing two calibration solutions, a precision value of less than 3‰ (2RSD) could be achieved for 184Os/188Os ratios, even if the 184OsO3‾ intensity was as low as 1000 cps. The precision values for the 186Os/188Os and 187Os/188Os ratios were similar and could be better than 0.066‰ (2RSD) when the intensities of 186OsO3‾ and 187OsO3‾ were greater than 30 mV, which can be obtained with conventional 1011 Ω amplifiers only at signals larger than 150 mV. Three geological reference materials were used in this study. The precision values of 184Os/188Os, 186Os/188Os, and 187Os/188Os ratios reached 2, 0.061, and 0.050‰ (2RSD), respectively, when the maximum Os amount was approximately 12 ng, and 87, 15, and 10‰ (2RSD), respectively, when the maximum Os amount was as low as approximately 66 pg. Additionally, our results show that changes in the volume of oxygen added during measurement can cause significant variations in the oxygen isotope composition. This static measurement method not only avoids the nonlinear signal change of the instrument during the analysis process but also realizes the accurate removal of the oxygen isobaric interference in the run, which could improve the precision of 184Os/188Os, 186Os/188Os, and 187Os/188Os ratios for small-size/low-signal samples.

Remote ischemic preconditioning and clinical outcomes after pediatric cardiac surgery: a systematic review and meta-analysis.

BACKGROUND: The benefit of remote ischemia preconditioning (RIPreC) in pediatric cardiac surgery is unclear. The objective of this systematic review and meta-analysis was to examine the effectiveness of RIPreC in reducing the duration of mechanical ventilation and intensive care unit (ICU) length of stay after pediatric cardiac surgery. METHODS: We searched PubMed, EMBASE and the Cochrane Library from inception to December 31, 2022. Randomized controlled trials comparing RIPreC versus control in children undergoing cardiac surgery were included. The risk of bias of included studies was assessed using the Risk of Bias 2 (RoB 2) tool. The outcomes of interest were postoperative duration of mechanical ventilation and ICU length of stay. We conducted random-effects meta-analysis to calculate weighted mean difference (WMD) with 95% confidence interval (CI) for the outcomes of interest. We performed sensitivity analysis to examine the influence of intraoperative propofol use. RESULTS: Thirteen trials enrolling 1,352 children were included. Meta-analyses of all trials showed that RIPreC did not reduce postoperative duration of mechanical ventilation (WMD -5.35 h, 95% CI -12.12-1.42) but reduced postoperative ICU length of stay (WMD -11.48 h, 95% CI -20.96- -2.01). When only trials using propofol-free anesthesia were included, both mechanical ventilation duration (WMD -2.16 h, 95% CI -3.87- -0.45) and ICU length of stay (WMD -7.41 h, 95% CI -14.77- -0.05) were reduced by RIPreC. The overall quality of evidence was moderate to low. CONCLUSIONS: The effects of RIPreC on clinical outcomes after pediatric cardiac surgery were inconsistent, but both postoperative mechanical ventilation duration and ICU length of stay were reduced in the subgroup of children not exposed to propofol. These results suggested a possible interaction effect of propofol. More studies with adequate sample size and without intraoperative propofol use are needed to define the role of RIPreC in pediatric cardiac surgery.

A new method for calibrating the current gain of 1013 Ω amplifiers in thermal ionization mass spectrometry.

We report a new method for calibrating the current gain of 1013  Ω amplifiers in both positive and negative mode used in thermal ionisation mass spectrometry (TIMS). This method uses any isotopic standard or sample to calibrate the gain factor as long as it can produce a stable current signal. It is simpler and more flexible than that recommended by Thermo-Fisher (the manufacture of the TIMS). In these analyses, the gains of five 1013  Ω amplifiers were assessed. The precision of gain factors was better than 100 ppm (2 RSD) in a day, and the long-term reproducibility was better than 300 ppm (2 RSD) within 2 to 8 months. After a gain was calibrated, the ratio accuracy and precision in the positive mode for 87 Sr/88 Sr of NIST 987 Sr and 143 Nd/144 Nd of La Jolla Nd were 0.710242 ± 60 (2 SD, n = 14) and 0.511842 ± 10 (2 SD, n = 22), respectively, at intensities of 88 Sr 0.3 V and 142 Nd 0.4 V, while in the negative mode for 187 Os/188 Os of Merck Os was 0.120229 ± 34 (2 SD, n = 23) at an intensity of 187 OsO3 0.01 mV. In addition, a difference in the gain factors between the negative mode TIMS (NTIMS) and positive mode TIMS (PTIMS) has been recognized. The values of the gain factor for NTIMS and PTIMS show a deviation of 0.54% on the Triton and 0.31% on the Triton Plus TIMS in this study; therefore, gain calibration should be carried out on both NTIMS and PTIMS. Moreover, a bias of ~ 1.5 × 10-5 between H and L Faraday cups for the same 1013  Ω amplifier has been detected, hinting that the efficiency of different Faraday cups may affect the gain factors, which can be eliminated through the new method of "cross-calibration" discribed in this study.

[Vertebroplasty compared with conservative method of integrated Chinese and Western Medicine in patients with osteoporotic vertebral compression fractures].

OBJECTIVE: To compare the effects of percutaneous vertebroplasty (PVP) versus conservative method of integrated Chinese and Western Medicine for pain relief and functional outcome in patients with painful osteoporotic vertebral fractures. New fractures and secondary adverse effects were also analyzed during a mid-long term follow-up period. METHODS: Patients were recruited to this prospective nonrandomized trial from a single hospital. Patients were aged 55 years or older, had vertebral compression fractures on spine radiograph (level of fracture at T6 or lower; bone oedema on MRI), with back pain for 6 weeks or less, and a visual analogue scale (VAS) score of 6 or more. Patients were nonrandomly assigned to PVP group or conservative treatment group according to their own desire. After 2 weeks, patients from the conservative group could change therapy to PVP. VAS for pain and Oswestry disability index (ODI) questionnaire scores were assessed before and 1 week, 1 month, 3, 6, 12, 24, 36, 48, and 60 months after the treatment. Other data included patients' baseline characteristics before the treatment, new fractures and secondary adverse effects were also recorded. RESULTS: A total of 181 consecutive patients were nonrandomly allocated to receive PVP (n=103) or conservative treatment (n=78) between December 2009 and August 2013. Six patients transferred to PVP group after 2 weeks conservative therapy. Pain relief and functional outcomes were significantly better in PVP group than in conservative group, as determined by VAS scores (3.67-1.13 vs 7.38-2.39) and ODI scores (23.55-5.83 vs 36.10-13.88) at 1 week, 1 month, 3 and 6 months (all P< 0.01). Both VAS and ODI scores decreased in PVP group showed no statistical significance at 1 year when compared with conservative group (P>0.05). However, pain relief and functional outcomes were significantly better at most of the subsequent follow-up points. The patients with complete pain relief (VAS<1) were significantly better in PVP group than in conservative group (P< 0.01) at all of the follow-up points. There were 17 patients died (PVP group: n=8) and 31 cases occurred secondary vertebral fractures (PVP group: n=19) during the follow-up periods. No serious complications or adverse events were related to PVP technique. CONCLUSION: PVP has immediate pain relief and functional improvement compared with conservative treatment. PVP should be considered as the treatment of first choice for symptomatic osteoporotic vertebral fractures. However, for patients with VAS < 5, conservative method of integrated Chinese and Western Medicine may perform well.

Risk factors for new vertebral fractures after percutaneous vertebroplasty in patients with osteoporosis: a prospective study.

PURPOSE: To determine the risk factors for new vertebral compression fractures (VCFs) following percutaneous vertebroplasty (PV) in patients with osteoporosis. MATERIALS AND METHODS: This prospective study included 132 consecutive patients with osteoporosis treated with PV in a single institution over 46 months from March 2005 to December 2008. Multivariable logistic regression and univariate analysis were employed to identify risk factors for new VCFs after PV, including patient demographic data, parameters of the initial and new fractured vertebrae, procedure-related information, and follow-up data. RESULTS: During the follow-up period (22.4 months ± 12.1), 80 new vertebral fractures occurred in 36 (27.3%) patients. Multivariate analysis showed that number of VCFs per time frame, computed tomography (CT) value of nonfractured vertebrae (T11-L2), activity level after discharge, duration of follow-up, and cement distribution in the inferior part of the vertebral body or close to the endplate were statistically correlated with new fractures (odds ratios, 2.63, 0.96, 3.59, 1.00, 0.30, and 0.05; P = .006, P = .001, P = .007, P = .004, P = .021 and P = .029). Univariate analysis showed preexisting old VCFs were correlated with new VCFs (P = .045). Subsequent compression fractures in adjacent vertebrae (45 of 80) occurred more frequently and sooner than nonadjacent vertebral fractures (both P < .05). CONCLUSIONS: The incidence of new VCFs after PV is relatively high and affected by several risk factors that are related to both the PV procedure and the natural course of osteoporosis.

[Influencing factors of long-mid term efficacy following percutaneous vertebroplasty in patients with osteoporosis].

OBJECTIVE: To determine the therapeutic efficacy and the influencing factors for the long/middle-term outcomes of percutaneous vertebroplasty (PVP) in the treatment of painful osteoporotic vertebral compression fractures (OVCFs). METHODS: This prospective study recruited a total of 131 consecutive OVCF patients treated with PVP at a single institution from March 2005 to December 2009. There were 106 females and 25 males. Pre- and postoperative evaluations included a visual analog scale (VAS) for pain, the Roland-Morris disability questionnaire (RDQ) scores and patient activity levels. Various factors probably correlated with long-mid term efficacy were also analyzed. RESULTS: Both VAS and RDQ scores decreased significantly (P < 0.05). And the activity levels showed significant post-therapeutic improvement (P < 0.01); Univariate and multivariate analysis showed that the influencing factors for the long/middle-term efficacy were age, number of OVCF(s) per time, activity level after discharge and newly occurring OVCF (Z = -2.03, -2.68, 5.38 and -1.73; P = 0.043, 0.007, 0.001 and 0.034 respectively). CONCLUSION: PVP is an efficient pain-relieving procedure. The long/middle-term efficacy after PVP is mostly correlated with both the patient age and the natural course of underlying conditions.

Long-term outcomes of patients with lumbar disc herniation treated with percutaneous discectomy: comparative study with microendoscopic discectomy.

We assessed the long-term outcomes of patients with lumbar disc herniation treated with percutaneous lumbar discectomy (PLD) or microendoscopic discectomy (MED). A retrospective study was performed in consecutive patients with lumbar disc herniation treated with PLD (n = 129) or MED (n = 101) in a single hospital from January 2000 to March 2002. All patients were followed up with MacNab criteria and self-evaluation questionnaires comprising the Oswestry Disability Index and Medical Outcomes Study 36-Item Short-Form Health Survey. Several statistical methods were used for analyses of the data, and a p value of <0.05 was considered to be statistically significant. A total of 104 patients (80.62%) with PLD and 82 patients (81.19%) with MED were eligible for analyses, with a mean follow-up period of 6.64 +/- 0.67 years and 6.42 +/- 0.51 years, respectively. There were no significant differences between the two groups in age, number of lesions, major symptoms and physical signs, and radiological findings. According to the MacNab criteria, 75.96% in the PLD group and 84.15% in the MED group achieved excellent or good results, respectively, this was statistically significant (p = 0.0402). With the Oswestry Disability Index questionnaires, the average scores and minimal disability, respectively, were 6.97 and 71.15% in the PLD group and 4.89 and 79.27% in the MED group. Total average scores of Medical Outcomes Study 36-Item Short-Form Health Survey were 75.88 vs. 81.86 in PLD group vs. MED group (p = 0.0582). The cost and length of hospitalization were higher or longer in MED group, a statistically significant difference (both p < 0.0001). Long-term complications were observed in two patients (2.44%) in the MED group, no such complications were observed in the PLD group. Both PLD and MED show an acceptable long-term efficacy for treatment of lumbar disc herniation. Compared with MED patients, long-term satisfaction is slightly lower in the PLD patients; complications, hospitalization duration, and costs in PLD group are also lower.

[Long-term outcomes of percutaneous lumbar discectomy and microendoscopic discectomy for lumbar disc herniation].

OBJECTIVE: To evaluate the long-term effects of percutaneous lumbar discectomy (PLD) and microendoscopic discectomy (MED) in treatment of lumbar disc herniation. METHODS: A questionnaire survey by letter and telephone was conducted among 104 patients undergoing PLD and 82 patients undergoing MED during January 2000 to March 2002, to investigate the Oswestry disability index (ODI), Short Form-36 (SF-36) score, and Japanese Orthopedic Association (JOA) score. RESULTS: The excellent/good rate (ODI score=0-20%) of the MED group was 79.27%, significantly higher than that of the PLD group (71.15%, P=0.0397). However, longer The hospitalization duration of the MED group was 11, 6 d, significantly longer than that of the PLD group (7.9 d, P<0.01), and the mean cost of the MED group was, significantly higher than that of the PLD group (P<0.01). Long-term complications were observed in 3 patients of the MED group (3.49%) while none in the PLD group. CONCLUSION: Both PLD and MED are minimally-invasive-technique with a long-term efficacy and safety on lumbar disc herniation. Although the long-term outcome of the MED group is better than PLD, the complication rate, hospitalization duration, and cost of the MED group are higher.