Application of ATONA Amplifiers to the Measurement of Uranium Isotopic Ratios by Thermal Ionization Mass Spectrometry.

Uranium isotopic composition can provide valuable information about the history and provenance of a nuclear material; therefore, uranium isotopic analyses are frequently made in the nuclear forensics, safeguards, and environmental monitoring communities. These measurements have always presented challenges due to the extreme variability in the relative abundance between the major (235U, 238U) and minor (233U, 234U, 236U) isotopes of uranium. The recently developed ATONA (Atto- to Nano-Amp) amplification system paired with Faraday cup detectors has a large dynamic range and low noise floor making it ideal for measuring uranium isotopic ratios in materials of both natural and anthropogenic origin. A wide variety of certified reference materials were analyzed to investigate the utility of the ATONA amplification system for determining uranium isotopic composition in samples ranging from depleted to highly enriched. The ATONA amplifiers provide nearly an order of magnitude improvement in external reproducibility over 1011 Ω amplifiers when measuring the minor 234U/238U ratio in isotopically natural and depleted samples and when paired with a secondary electron multiplier can measure very low relative abundance uranium isotopes (i.e., 236U).

Ultrasound-Assisted Spinal Anesthesia in a Patient with a Preexisting Lumbar Interspinous Spacer: A Case Report.

An interspinous spacer is a minimally invasive implantable device for the treatment of lumbar spinal stenosis. The in situ implant may prevent safe and successful spinal anesthesia because its position can obstruct the path of the spinal needle. Lumbar neuraxial ultrasonography has been shown to aid in performance of neuraxial anesthesia in patients with challenging anatomy. Currently, there are no reported cases of ultrasound-assisted spinal anesthesia in patients with interspinous spacers. We present a case in which ultrasonography assisted the successful administration of a spinal anesthetic by avoiding an indwelling lumbar interspinous spacer.

Association between perioperative non-steroidal anti-inflammatory drug use and cardiovascular complications after non-cardiac surgery in older adult patients.

BACKGROUND: We investigated in older adult non-cardiac surgical patients whether receipt of perioperative non-steroidal anti-inflammatory drugs (NSAIDs) is associated with increased incidence of postoperative cardiovascular complications. METHODS: We retrospectively extracted the information for patients with age ≥  65 years who had inpatient non-cardiac surgery with a duration of ≥  1 h from the American College of Surgeons-National Surgical Quality Improvement Program registry data acquired at the University of Washington Medical Center. We compared patients who received NSAIDs perioperatively to those who did not receive NSAIDs, on the two composite outcomes: (1) the incidence of postoperative cardiovascular complications within 30 days of the surgery, and (2) the incidence of combined postoperative gastrointestinal and renal complications, and length of postoperative hospital stay. We used separate multivariable logistic regression models to analyze the two composite outcomes and a Poisson regression model for the length of hospital stay. RESULTS: The receipt of perioperative NSAIDs was not associated with postoperative cardiovascular complications (estimated odds ratio (OR), 1.78; 95% confidence interval (CI), 0.97 to 3.25; P =  0.06), combined renal and gastrointestinal complications (estimated OR, 1.30; 95% CI, 0.53 to 3.20; P =  0.57), and length of postoperative hospital stay in days (incidence rate ratio, 1.06; 95% CI, 0.93 to 1.21; P =  0.39). CONCLUSIONS: In older adult non-cardiac surgical patients, receipt of perioperative NSAIDs was not associated with increased incidences of postoperative cardiovascular complications, and renal and gastrointestinal complications within 30 days after surgery, or length of postoperative hospital stay.

Oxygen Isotope and Fluorine Impurity Signatures during the Conversion of Uranium Ore Concentrates to Nuclear Fuel.

Within the front end of the nuclear fuel cycle, many processes impart forensic signatures. Oxygen-stable isotopes (δ18O values) of uranium-bearing materials have been theorized to provide the processing and geolocational signatures of interdicted materials. However, this signature has been minimally utilized due to a limited understanding of how oxygen isotopes are influenced during uranium processing. This study explores oxygen isotope exchange and fractionation between magnesium diuranate (MDU), ammonium diuranate (ADU), and uranyl fluoride (UO2F2) with steam (water vapor) during their reduction to UOx. The MDU was precipitated from two water sources, one enriched and one depleted in 18O. The UO2F2 was precipitated from a single water source and either directly reduced or converted to ADU prior to reduction. All MDU, ADU, and UO2F2 were reduced to UOx in a 10% hydrogen/90% nitrogen atmosphere that was dry or included steam. Powder X-ray diffraction (p-XRD) was used to verify the composition of materials after reduction as mixtures of primarily U3O8, U4O9, and UO2 with trace magnesium and fluorine phases in UOx from MDU and UO2F2, respectively. The bulk oxygen isotope composition of UOx from MDU was analyzed using fluorination to remove the lattice-bound oxygen, and then O2 was subsequently analyzed with isotope ratio mass spectrometry (IRMS). The oxygen isotope compositions of the ADU, UO2F2, and the resulting UOx were analyzed by large geometry secondary ion mass spectrometry (LG-SIMS). When reduced with steam, the MDU, ADU, and UO2F2 experienced significant oxygen isotope exchange, and the resulting δ18O values of UOx approached the values of the steam. When reduced without steam, the δ18O values of converted ADU, U3O8, and UOx products remained similar to those of the UO2F2 starting material. LG-SIMS isotope mapping of F impurity abundances and distributions showed that direct steam-assisted reduction from UO2F2 significantly removed F impurities while dry reduction from UO2F2 led to the formation of UOx that was enhanced in F impurities. In addition, when UO2F2 was processed via precipitation to ADU and calcination to U3O8, F impurities were largely removed, and reductions to UOx with and without steam each had low F impurities. Overall, these findings show promise for combining multiple signatures to predict the process history during the conversion of uranium ore concentrates to nuclear fuel.

Critical lessons from a pragmatic randomized trial of home-based COVID-19 testing in rural Native American and Latino communities.

PURPOSE: Native Americans and Latinos have higher COVID-19 infection and mortality rates and may have limited access to diagnostic testing. Home-based testing may improve access to care in rural and underserved populations. This study tests the effect of community health worker (CHW) support on accessibility, feasibility, and completion of COVID-19 home testing among Native American and Latino adults living on the Flathead Reservation in Montana and in Yakima Valley, Washington. METHODS: A two-arm, multisite, pragmatic randomized controlled trial was conducted using block randomization stratified by site and participant age. Active arm participants received CHW assistance with online COVID-19 test kit registration and virtual swabbing support. The passive arm participants received standard-of-care support from the kit vendor. Logistic regression modeled the association between study arm and test completion (primary outcome) and between study arm and test completion with return of valid test results (secondary outcome). Responses to posttest surveys and interviews were summarized using deductive thematic analysis. FINDINGS: Overall, 63% of participants (n = 268) completed COVID-19 tests, and 50% completed tests yielding a valid result. Active arm participants had higher odds of test completion (odds ratio: 1.66, 95% confidence interval [1.01, 2.75]). Differences were most pronounced among adults ≥60 years. Participants cited ease of use and not having to leave home as positive aspects, and transportation and mailing issues as negative aspects of home-based testing. CONCLUSIONS: CHW support led to higher COVID-19 test completion rates, particularly among older adults. Significant testing barriers included language, educational level, rurality, and test kit issues.

Postinjury Alcohol Use Is Associated With Prolonged Recovery After Concussion in NCAA Athletes.

OBJECTIVE: To determine whether alcohol use leads to prolonged clinical recovery or increased severity of concussion symptoms in National Collegiate Athletic Association (NCAA) athletes. DESIGN: Prospective observational study. SETTING: Clinical institutions. PARTICIPANTS: Athletes from the NCAA Concussion Assessment Research and Education consortium who sustained a concussion from 2014 to 2021. INTERVENTIONS: Athletes were divided into 2 groups, those reporting alcohol use postinjury and those reporting no alcohol use postinjury. MAIN OUTCOME MEASURES: Symptom recovery was evaluated as time (in days) from injury to clearance to return to unrestricted play (days until URTP). Severity of concussion symptoms was assessed using the Standardized Sport Concussion Assessment Tool (SCAT3) symptom severity, headache severity, difficulty concentrating, and difficulty remembering scores. These scores were taken a median of 6.6 [interquartile range (IQR) = 4.0-10] and 6 (IQR = 4.0-9.0) days after injury for those who did and did not consume alcohol postinjury respectively and compared with baseline SCAT3 scores. RESULTS: Four hundred eighty four athletes from the data set had complete data for exposure and outcome. The adjusted mean number of days until URTP for athletes reporting alcohol use postinjury [23.3; 95% confidence interval (CI), 20.0-27.2; days] was incidence rate ratio (IRR) 1.32 (95% CI, 1.12-1.55; P < 0.001) times higher than for athletes who reported no alcohol use postinjury [17.7 (95% CI, 16.1-19.3) days]. Postinjury alcohol was not associated with severity of concussion symptoms ( P 's < 0.05). CONCLUSION: Self-reported postinjury alcohol use is associated with prolonged recovery but not severity of concussion symptoms in collegiate athletes. This may inform future clinical recommendations regarding alcohol consumption after concussion.

Association Between Postoperative Methocarbamol and Postoperative Pain Opioid Dose Requirements: A Retrospective Cohort Study.

OBJECTIVES: We tested the hypothesis that patients who received methocarbamol postoperatively experience less severe pain and require smaller doses of opioids than those who did not receive methocarbamol. MATERIALS AND METHODS: This is a retrospective cohort study of patients undergoing surgery involving the musculoskeletal system. Of 9089 patients, 704 received methocarbamol during 48 hours postoperatively, while 8385 did not receive methocarbamol. The patients who received methocarbamol postoperatively and the patients who did not receive methocarbamol were compared on the time-weighted average (TWA) pain score and opioid dose requirements in morphine milligram equivalents (MME) during the first 48 hours postoperatively, using propensity score-weighted regression models to adjusting for preoperative and intraoperative covariates. RESULTS: Postoperative 48-hour TWA pain scores were 5.5±1.7 (mean±SD), and 4.3±2.1 for methocarbamol and non-methocarbamol patients. Postoperative 48-hour opioid dose requirements in MME were 276 [170-347] (median [interquartile range (IQR)]) mg, and 190 [60-248] mg for methocarbamol and non-methocarbamol patients. In propensity score-weighted regression models, receiving methocarbamol postoperatively was associated with 0.97-point higher postoperative TWA pain score (95% CI, 0.83-1.11; P <0.001), and 93.6-MME higher postoperative opioid dose requirements (95% CI, 79.9 to 107.4; P <0.001), compared with not receiving methocarbamol postoperatively. DISCUSSION: Postoperative methocarbamol was associated with significantly higher acute postoperative pain burden and opioid dose requirements. Although the results of the study are influenced by residual confounding, they suggest a limited-if any-benefit of methocarbamol as an adjunct of postoperative pain management.

Regional Anesthesia Techniques for Shoulder Surgery in High-Risk Pulmonary Patients.

Patients with pre-existing pulmonary conditions are at risk for experiencing perioperative complications and increased morbidity. General anesthesia has historically been used for shoulder surgery, though regional anesthesia techniques are increasingly used to provide anesthesia and improved pain control after surgery. Relative to regional anesthesia, patients who undergo general anesthesia may be more prone to risks of barotrauma, postoperative hypoxemia, and pneumonia. High-risk pulmonary patients, in particular, may be exposed to these risks of general anesthesia. Traditional regional anesthesia techniques for shoulder surgery are associated with high rates of phrenic nerve paralysis which significantly impairs pulmonary function. Newer regional anesthesia techniques have been developed, however, that provide effective analgesia and surgical anesthesia while having much lower rates of phrenic nerve paralysis, thereby preserving pulmonary function.

Association between postictal EEG suppression, postictal autonomic dysfunction, and sudden unexpected death in epilepsy: Evidence from intracranial EEG.

OBJECTIVE: The association between postictal electroencephalogram (EEG) suppression (PES), autonomic dysfunction, and Sudden Unexpected Death in Epilepsy (SUDEP) remains poorly understood. We compared PES on simultaneous intracranial and scalp-EEG and evaluated the association of PES with postictal heart rate variability (HRV) and SUDEP outcome. METHODS: Convulsive seizures were analyzed in patients with drug-resistant epilepsy at 5 centers. Intracranial PES was quantified using the Hilbert transform. HRV was quantified using root mean square of successive differences of interbeat intervals, low-frequency to high-frequency power ratio, and RR-intervals. RESULTS: There were 64 seizures from 63 patients without SUDEP and 11 seizures from 6 SUDEP patients. PES occurred in 99% and 87% of seizures on intracranial-EEG and scalp-EEG, respectively. Mean PES duration in intracranial and scalp-EEG was similar. Intracranial PES was regional (<90% of channels) in 46% of seizures; scalp PES was generalized in all seizures. Generalized PES showed greater decrease in postictal parasympathetic activity than regional PES. PES duration and extent were similar between patients with and without SUDEP. CONCLUSIONS: Regional intracranial PES can be present despite scalp-EEG demonstrating generalized or no PES. Postictal autonomic dysfunction correlates with the extent of PES. SIGNIFICANCE: Intracranial-EEG demonstrates changes in autonomic regulatory networks not seen on scalp-EEG.

Amputation for Complex Regional Pain Syndrome: Meta-Analysis and Validation of a Histopathology Scoring System.

OBJECTIVE: Pathology can provide crucial insights into the etiology of disease. The goal of this review is to evaluate the rigor of histopathology reports of Complex Regional Pain Syndrome (CRPS). METHODS: A systematic search of multiple databases identified papers that described amputation for CRPS with pathology findings. Control pathology articles were randomly chosen from the same journals. Landmark articles in Surgical Pathology were previously identified. Papers were categorized by the use of histology: Anatomic (microscopic description), Diagnostic (binary result), and Substrate (special studies only). A novel Histopathology Score assigned 1 point for each of 10 History elements and 15 Pathology elements. All articles were scored and analyzed by appropriate statistics. RESULTS: The search identified 22 CRPS, 50 Control and 50 Landmark articles. Multivariable analysis of the Pathology Score showed a significantly higher score for Anatomic vs Non-Anatomic papers (Incidence Rate Ratio (IRR) 1.54, P < .001) and Landmark vs CRPS articles (IRR 1.39, P value .003). CRPS papers reported some elements infrequently: diagnostic criteria (31.8%), routine stain (50%), any clinic-pathologic correlation (40.9%), and sample size >2 (27.3%). CONCLUSIONS: The Pathology Score is a useful quality assessment tool to evaluate studies. As expected, Anatomic papers scored significantly higher than Non-Anatomic papers. CRPS papers had small sample sizes (median 1) and infrequent reporting of diagnostic criteria, routine stain, any clinical pathologic correlation. These particular elements are crucial for analyzing and reviewing pathologic features. The analysis explains why it is quite difficult to write a meaningful systematic review of CRPS histology at this time.

Analyses of correct responses and errors on measures of verbal fluency among Parkinson's disease and essential tremor patients.

Objective: Parkinson's disease (PD) and essential tremor (ET) involve neuroanatomical circuitry that impact frontal lobe functioning, via the striatum and cerebellum, respectively. The aim of this exploratory study was to investigate quantitative and qualitative performance between and within these groups on measures of verbal fluency. Method: Sixty-three PD and 53 ET patients completed neuropsychological testing. Linear regression models with robust variance estimation compared verbal fluency performance between groups related to correct responses and errors. Paired t-tests investigated within group error rates. Results: PD patients gave more correct responses for phonological (ß̂ =5.3, p=.01) and category fluency (ß̂ =4.1, p=.01) than ET patients; however, when processing speed was added as a covariate, this attenuated performance on both measures and only phonological fluency remained significant (ß̂ =4.0, p=.04). There were no statistical differences in error scores between groups. Error rates within groups suggested that PD patients had higher error rates in total errors and perseveration errors on phonological fluency (M = 2.6, p=.00; M = 1.6, p=.00) and higher total errors and set-loss error rates on category switching (M = 5.1, p<.001; M = 4.1, p<.001). ET patients had higher error rate with relation to total errors and set-loss errors on phonological fluency (M = 2.5, p=.00; M = 1.5, p=.02) and category switching (M = 3.9, p=,00; M = 3.9, p<.001). Conclusions: PD patients performed better than ET patients on phonological fluency. PD patients appear to make more perseveration errors on phonological fluency, while ET patients made more set-loss errors. Implications for frontal lobe dysfunction and clinical impact are discussed.

Detectability of Small Low-Attenuation Lesions With Deep Learning CT Image Reconstruction: A 24-Reader Phantom Study.

BACKGROUND. Iterative reconstruction (IR) techniques are susceptible to contrast-dependent spatial resolution, limiting overall radiation dose reduction potential. Deep learning image reconstruction (DLIR) may mitigate this limitation. OBJECTIVE. The purpose of our study was to evaluate low-contrast detectability performance and radiation-saving potential of a DLIR algorithm in comparison with filtered back projection (FBP) and IR using a human multireader noninferiority study design and task-based observer modeling. METHODS. A dual-phantom construct, consisting of a low-contrast detectability module (21 low-contrast hypoattenuating objects in seven sizes [2.4-10.0 mm] and three contrast levels [-15, -10, -5 HU] embedded within liver-equivalent background) and a phantom, was imaged at five radiation exposures (CTDIvol range, 1.4-14.0 mGy; size-specific dose estimate, 2.5-25.0 mGy; 90%-, 70%-, 50%-, and 30%-reduced radiation levels and full radiation level) using an MDCT scanner. Images were reconstructed using FBP, hybrid IR (ASiR-V), and DLIR (TrueFidelity). Twenty-four readers of varying experience levels evaluated images using a two-alternative forced choice. A task-based observer model (detectability index [d']) was calculated. Reader performance was estimated by calculating the AUC using a noninferiority method. RESULTS. Compared with FBP and IR methods at routine radiation levels, DLIR medium and DLIR high settings showed noninferior performance through a 90% radiation reduction (except DLIR medium setting at 70% reduced level). The IR method was non-inferior to routine radiation FBP only for 30% and 50% radiation reductions. No significant difference in d' was observed between routine radiation FBP and DLIR high setting through a 70% radiation reduction. Reader experience was not correlated with diagnostic accuracy (R2 = 0.005). CONCLUSION. Compared with FBP or IR methods at routine radiation levels, certain DLIR algorithm weightings yielded noninferior low-contrast detectability with radiation reductions of up to 90% as measured by 24 human readers and up to 70% as assessed by a task-based observer model. CLINICAL IMPACT. DLIR has substantial potential to preserve contrast-dependent spatial resolution for the detection of hypoattenuating lesions at decreased radiation levels in a phantom model, addressing a major shortcoming of current IR techniques.

Analysis of Vaccine Reactions After COVID-19 Vaccine Booster Doses Among Pregnant and Lactating Individuals.

Importance: COVID-19 vaccine boosters or third doses are recommended for adolescents and adults who completed their initial COVID-19 vaccine course more than 5 months prior. Minimal data are available on COVID-19 vaccine booster or third dose reactogenicity among pregnant and lactating individuals. Objective: To describe the reactions to the booster or third dose of the COVID-19 vaccine and vaccine experiences among pregnant and lactating individuals. Design, Setting, and Participants: Beginning in October 2021, a follow-up Research Electronic Data Capture (REDCap) survey regarding a COVID-19 vaccine booster or third dose was sent to 17 504 participants in an ongoing online prospective cohort study on COVID-19 vaccines among pregnant and lactating individuals. A convenience sample of adults enrolled in the online prospective study who were pregnant, lactating, or neither pregnant nor lactating at the time of their booster or third dose was eligible for this follow-up survey; 17 014 (97.2%) completed the follow-up survey. Exposure: Receipt of a booster or third dose of the COVID-19 vaccine. Main Outcomes and Measures: Self-reported vaccine reactions less than 24 hours after the dose. Results: As of April 4, 2022, 17 014 eligible participants (mean [SD] age, 33.3 [3.5] years) responded to the booster or third dose survey; of these, 2009 (11.8%) were pregnant at the time of their booster or third dose, 10 279 (60.4%) were lactating, and 4726 (27.8%) were neither pregnant nor lactating. After a COVID-19 booster or third dose, most individuals (14 074 of 17 005 [82.8%]) reported a local reaction, and 11 542 of 17 005 (67.9%) reported at least 1 systemic symptom. Compared with individuals who were neither pregnant nor lactating, pregnant participants were more likely to report any local reaction to a COVID-19 booster or third dose (adjusted odds ratio [aOR], 1.2; 95% CI, 1.0-1.4; P = .01) but less likely to report any systemic reaction (aOR, 0.7; 95% CI, 0.6-0.8; P < .001). Most pregnant (1961 of 2009 [97.6%]) and lactating (9866 of 10 277 [96.0%]) individuals reported no obstetric or lactation concerns after vaccination. Conclusions and Relevance: This study suggests that COVID-19 vaccine boosters or third doses were well tolerated among pregnant and lactating individuals. Data to evaluate tolerability of boosters or additional doses among pregnant and lactating individuals will be important as they are considered for these populations.

A spin crossover FeII4L6 cage based on pyridyl-hydrazone sites.

Reported here is the first FeII based supramolecular cage with pyridyl-hydrazone ligand scaffolds that exhibits temperature induced spin crossover behaviour. Density functional theory calculations were employed to investigate the cause of the occurrence of this phenomenon based on the ligand structure. These results indicate that the reported low-spin cages with pyridyl-imine sites could be reconsidered for spin crossover by carefully manipulating the functional groups in the ligand system.

Determinants of Cervical Cancer Screening Patterns Among Women With Systemic Lupus Erythematosus.

OBJECTIVE: Women with systemic lupus erythematosus (SLE) are vulnerable to cervical dysplasia due to the persistence of human papillomavirus (HPV) infection. The objective of this cross-sectional retrospective study was to investigate the prevalence of cervical cancer screening according to the American Society for Colposcopy and Cervical Pathology (ASCCP) SLE-specific cervical cancer screening guidelines. We also aimed to identify SLE-specific determinants associated with ASCCP adherence. METHODS: Women aged 21 to 64 years enrolled in our institutional SLE registry were included in the study. The electronic medical record was manually reviewed to determine whether the patient was up to date on screening and which organizational guideline was used, in addition to other clinical variables. Multivariable logistic regression was used to estimate adjusted odds ratios (ORs) for ASCCP-congruent screening for each baseline characteristic. RESULTS: This study included 118 women with SLE; 38% were up to date per ASCCP guidelines, 16% were up to date per non-ASCCP guidelines, and 46% were overdue for screening. Having a gynecologist and being actively treated with immunosuppressant therapies were both associated with an increased odds of being up to date per the ASCCP guidelines, while Hispanic ethnicity was associated with reduced odds. CONCLUSION: Only half of the women with SLE in our study had guideline-congruent cervical cancer screening. Current immunosuppression exposure, rather than SLE disease activity, was associated with an increased odds of being up to date according to ASCCP guidelines. This study suggests the need for increased awareness and consensus among interdisciplinary providers regarding SLE-specific cervical cancer screening.

Postoperative respiratory depression in patients on sublingual buprenorphine: a retrospective cohort study for comparison between postoperative continuation and discontinuation of buprenorphine.

BACKGROUND: We tested the hypothesis that patients who continued buprenorphine postoperatively experience postoperative respiratory depression less frequently than those who discontinued buprenorphine. METHODS: This is a retrospective cohort study of patients who were on buprenorphine preoperatively. The primary outcome was postoperative respiratory depression as defined by respiratory rate < 10/minute, oxygen saturation (SpO2) < 90%, or requirement of naloxone for 48 h postoperatively. The secondary outcome was the composite of postoperative respiratory complications. The associations between postoperative buprenorphine continuation and respiratory depression and respiratory complications were estimated using separate multivariable logistic regression models, including demographic, intraoperative characteristics, and preoperative buprenorphine dose as covariates. RESULTS: Postoperative buprenorphine continuation was not associated with postoperative respiratory depression (adjusted odds ratio (OR), 1.11, 95% confidence interval (CI), 0.61 to 1.99, P=0.72). In subanalysis stratified by the preoperative buprenorphine dose, buprenorphine continuation was not associated with postoperative respiratory depression either when preoperative buprenorphine dose was high (≥16 mg daily) or low (<16 mg daily). Postoperative buprenorphine continuation was associated with lower incidence of postoperative respiratory complications (adjusted OR, 0.43, 95% CI, 0.21 to 0.86, P=0.02). CONCLUSIONS: Continuing buprenorphine was not associated with respiratory depression, but it was associated with a lower incidence of respiratory complications.

Perioperative management in complex spine surgery.

The last two decades have seen a significant increase in the number of spine surgical procedures performed worldwide. This type of surgery includes a wide variety of procedures, from mini-invasive discectomies to multilevel spinal arthrodesis and osteotomies. Moreover, different surgical approaches are described at different spine levels: the anesthesiologist should be aware of the potential benefits and risks for the patients and be prepared for their management. In this narrative review we seek to describe basic concepts of perioperative spine care and address evolving areas in which care is changing. We will discuss preoperative concerns, intraoperative management including airway management, choice of maintenance, intraoperative neuromonitoring and anesthetic effect, blood management and the dynamic topic of anesthetic and analgesic techniques. Finally, we will briefly address the issue of perioperative complications as they relate specifically to spine surgery.

Oxygen Isotope Fractionation in U3O8 during Thermal Processing in Humid Atmospheres.

The incorporation of oxygen isotopes from water into uranium oxides during industrial processing presents a pathway for determining a material's geographical origin. This study is founded on the hypothesis that oxygen isotopes from atmospheric water vapor will exchange with isotopes of oxygen in solid uranium oxides during thermal processing or calcination. Using a commonly encountered oxide, U3O8, the exchange kinetics and equilibrium fractionation with water vapor (in a concentration range of 50-55% relative humidity) were investigated using processing temperatures of 400, 600, and 800 °C. In an atmosphere containing only water vapor diluted in N2, oxygen isotope equilibration in U3O8 occurred within 12 h at 400 °C and within 2 h at 600 and 800 °C. Fractionation factors (1000lnα, U3O8-H2O) between the water and oxide were -12.1, -11.0, and -8.0 at 400, 600, and 800 °C, respectively. With both humidity and O2 present in the calcining atmosphere, isotopic equilibration is attained within 2 h at and above 400 °C. In this mixed atmosphere, which was designed to emulate Earth's troposphere, isotopes are incorporated preferentially from water vapor at 400 °C and from O2 at 600 and 800 °C. Rapid and temperature/species-dependent isotope exchange also elucidated the impact of retrograde exchange in humid air, showing a shift from O2-dependent to H2O-dependent fractionation as U3O8 cooled from 800 °C. These results confirm that uranium oxides inherit oxygen isotopes from humidity during thermal processing, illuminating an important mechanism in the formation of this forensic signature.

Age Adjusted Comorbidity Risk Index Does Not Predict Outcomes in an Autologous Hematopoietic Stem Cell Transplant Population.

The hematopoietic comorbidity risk index (HCT-CI) is a pre-transplant risk assessment tool used to prognosticate morbidity and mortality of patients undergoing allogeneic hematopoietic stem cell transplantation. Recently, the HCT-CI was updated to include an age component (HCT-CI-age). Although other studies have validated this tool in allogeneic stem cell transplant recipients, it has never been studied in an autologous transplant patient population. We retrospectively reviewed 181 patients who underwent their first autologous hematopoietic stem cell transplant. We aimed (1) to assess whether an HCT-CI score of 3 or greater is associated with greater mean transplant hospital days, greater total hospital days, or greater risk of intensive care unit (ICU) utilization and (2) whether age influences any of these responses independent of HCT-CI. There were 136 patients with an HCT-CI score of 3 or higher and 45 with a score less than 3. The length of initial transplant hospitalization in days was not statistically significant (15.6 v 16.4 days, P = 0.38). Utilizing spline modeling prediction curves, transplant hospital days were estimated to increase from a mean of 15.5 days for a patient with 4 comorbidities to a mean of 22.7 days for a patient with 8 comorbidities. Age made no significant impact on any of the outcomes. The HCT-CI, with or without age, in an autologous stem cell transplantation did not predict length of hospitalization or utilization of the ICU. Patients with higher-HCT-CI scores at baseline may incrementally utilize more resources, and this should be explored in a larger cohort population.