Introduction:. In the United States, tapered splined titanium stems (TSTSs) are the most frequently used femoral stem design in revision total hip arthroplasty. Despite encouraging and favorable results with TSTS, complications including femoral stem subsidence persist and subsidence >5 mm has been associated with implant failures and the need for aseptic rerevision surgery. We sought to investigate whether an extended trochanteric osteotomy (ETO) at the time of TSTS insertion increased mean subsidence and whether the amount of cortical contact was associated with subsidence, failure, and revision. Methods:. This is a single-center retrospective cohort study of a prospectively collected database including all patients who received a TSTS from 2016 to 2020. Data collected include surgery type, presence of an ETO, and stem specifications. Radiographs were reviewed to analyze cortical contact and postoperative subsidence. Pearson’s correlation coefficient was used to determine the association between contact length and subsidence. Results:. This cohort consisted of 299 hips, and 66 hips necessitated an ETO at the time of TSTS. Patients who required an ETO were more likely to subside (2.5 ± 0.2 mm vs 5.0 ± 0.7 mm, p < 0.001) and were more likely to subside >5 mm (32.3% vs 14.5%, p = 0.001). After controlling for other variables, an ETO was an independent risk factor for significant subsidence (adjusted OR: 3.4, p = 0.02). Contact length below the ETO was inversely related to stem subsidence (correlation coefficient of −0.26; p = 0.037), and multivariable logistic regression demonstrated bicortical contact > 30 mm to be a protective factor for significant subsidence (adjusted OR: 0.12, p < 0.001). Patients who received an ETO had a higher aseptic rerevision rate than patients who had a TSTS implanted without an ETO (16.1% vs 6.6%, p = 0.018). Conclusions:. Patients who receive an ETO during revision hip arthroplasty have a higher mean subsidence and 3-fold increase in odds for subsiding >5 mm. However, bicortical contact of 30 mm or greater below the ETO was protective against significant TSTS subsidence. Although not all patients with >5 mm of subsidence were revised, the aseptic rerevision rate was significantly higher in patients who received an ETO. Clinical Relevance:. An extended trochanteric osteotomy is an excellent technique to gain direct visualization of the femoral canal. However, it is not without its associated morbidity and postoperative complications, specifically stem subsidence. The results of this study suggest that when preparing for a TSTS after an ETO, careful consideration should be taken to confirm 3 cm of cortical engagement below the transverse limb of the ETO. The scaffolding technique, which prioritizes stem preparation followed by ETO closure, facilitates achieving sufficient cortical contact in the intact canal below the ETO segment. Consideration for intraoperative radiographs to confirm appropriate contact length and location may ensure sufficient fixation that will minimize the risk of postoperative stem subsidence. Level of Evidence:. Level III. See Instructions for Authors for a complete description of levels of evidence.

STUDY DESIGN:Retrospective analysis of prospectively enrolled patients. OBJECTIVE:To evaluate the relationship between paraspinal muscle (PM) atrophy and Oswestry Disability Index (ODI) improvement after spinal fusion surgery for degenerative lumbar spondylolisthesis. BACKGROUND:Atrophy of the PM is linked to multiple spinal conditions, sagittal malalignment, and increased postoperative complications. However, only limited evidence for the effect on patient-reported outcomes exists. METHODS:Patients with degenerative lumbar spondylolisthesis undergoing decompression and fusion surgery were analyzed. Patients with missing follow-up, no imaging, or inadequate image quality were excluded. The ODI was assessed preoperatively and two years postoperatively. A cross-sectional area of the PM was measured on a T2-weighted magnetic resonance imaging sequence at the upper endplate of L4. On the basis of the literature, a 10-point improvement cutoff was defined as the minimum clinically important difference. Patients with a baseline ODI below the minimum clinically important difference were excluded. Logistic regression was used to calculate the association between fatty infiltration (FI) of the PM and improvement in ODI, adjusted for age, sex, and body mass index. RESULTS:A total of 133 patients were included in the final analysis, with only two lost to follow-up. The median age was 68 years (IQR 62-73). The median preoperative ODI was 23 (IQR 17-28), and 76.7% of patients showed improvement in their ODI score by at least 10 points. In the multivariable regression, FI of the erector spinae and multifidus increased the risk of not achieving clinically relevant ODI improvement ( P =0.01 and <0.001, respectively). No significant association was found for the psoas muscle ( P =0.158). CONCLUSIONS:This study demonstrates that FI of the erector spinae and multifidus is significantly associated with less likelihood of clinically relevant ODI improvement after decompression and fusion. Further research is needed to assess the effect of interventions.

Study Design. Retrospective longitudinal study. Objective. To investigate the association between lumbar intervertebral disk degeneration (DD) and the vertebral bone quality (VBQ) score. Background. The VBQ score that is based on magnetic resonance imaging has been proposed as a measure of lumbar spine bone quality and is a significant predictor of healthy versus osteoporotic bone. However, the role of segmental contributing factors on VBQ is unknown. Methods. Nonsurgical patients who underwent repeated lumbar magnetic resonance imaging scans, at least three years apart primarily for low back pain were retrospectively included. VBQ was assessed as previously described. DD was assessed using the Pfirrmann grading (PFG) scale. PFG grades were summarized as PFG L1-4 for the upper three lumbar disk levels, as PFG L4-S1 for the lower two lumbar disc levels, and as PFG L1-S1 for all lumbar disc levels. Multivariable linear mixed models were used with adjustments for age, sex, race, body mass index, and the clustering of repeated measurements. Results. A total of 350 patients (54.6% female, 85.4% White) were included in the final analysis, with a median age at baseline of 60.1 years and a body mass index of 25.8 kg/m 2 . VBQ significantly increased from 2.28 at baseline to 2.36 at follow-up ( P = 0.001). In the unadjusted analysis, a significant positive correlation was found between PFG L1-4 , PFG L1-S1 , and VBQ at baseline ( P < 0.05) that increased over time ( P < 0.005). In the adjusted multivariable analysis, PFG L1-4 ( β = −0.0195; P = 0.021), PFG L4-S1 ( β = −0.0310; P = 0.007), and PFG L1-S1 ( β = −0.0160; P = 0.012) were independently and negatively associated with VBQ. Conclusions. More advanced and long-lasting DD is associated with lower VBQ indicating less bone marrow fat content and potentially stronger bone. VBQ score as a marker of bone quality seems affected by DD.

Introduction:The vertebral bone quality (VBQ) score that is based on non-contrast enhanced T1-weighted MRI was recently introduced as a novel measure of bone quality in the lumbar spine and shown to be a significant predictor of healthy versus osteopenic/osteoporotic bone. Research question:This study aimed to assess possible correlations between the VBQ score and the functional cross-sectional area (FCSA) of psoas and lumbar spine extensor muscles. Material and methods:Patients who underwent fusion surgery between 2014 and 2017 and had lumbar MRI and CT scans within 6 months prior to surgery were included. The FCSA was assessed at L3-L5 using a pixel intensity threshold method. The VBQ score was calculated by dividing the signal intensity (SI) of the vertebrae L1-L4 through the SI of the cerebrospinal fluid at L3. Volumetric bone mineral density (vBMD) was assessed by quantitative CT. Results:80 patients (58.8% female, median age 68.8 years) were included. Overall prevalence of osteopenia/osteoporosis was 66.3%, with no significant differences between men and women. The mean (SD) VBQ score was significantly smaller in men, at 2.26 (0.45) versus women at 2.59 (0.39) (p = 0.001). After adjusting for age and BMI, a significant negative correlation was seen between the VBQ score and psoas FCSA at L3 (β = -0.373; p = 0.022), but only in men. Conclusion:Our results highlight sex differences in the VBQ score that were not demonstrated by vBMD and suggest a potential role of this novel measure to assess not only bone quality, but also spinal muscle quantity.

To investigate the influence of vertebral endplate defects and subchondral bone marrow changes on the development of lumbar intervertebral disc degeneration (DD). Patients > 18 y/o without any history of lumbar fusion who had repeat lumbar magnetic resonance imaging scans primarily for low back pain (LBP) performed at a minimum of 3 years apart at a single institution, and no spinal surgery in between scans were included. Total endplate score (TEPS), Modic changes (MC), and Pfirrmann grading (PFG) per lumbar disc level were assessed. DD was defined as PFG ≥ 4. Three hundred and fifty-three patients (54.4

Study design: A retrospective observational study. Objective. The objective of this study was to investigate the factors associated with the conversion of patient status from ambulatory surgery (AMS) to observation service (OS) (<48 h) or inpatient (>48 h). Summary of Background Data. AMS is becoming increasingly common in the United States because it is associated with a similar quality of care compared with inpatient surgery, significant costs reduction, and patients’ desire to recuperate at home. However, there are instances when AMS patients may be subjected to extended hospital stays. Unanticipated extension of hospitalization stays can be a great burden not only to patients but to medical providers and insurance companies alike. Materials and Methods. Data from 1096 patients who underwent one-level or two-level lumbar decompression AMS at an in-hospital, outpatient surgical facility between January 1, 2019, and March 16, 2020, were collected. Patients were categorized into three groups based on length of stay: (1) AMS, (2) OS, or (3) inpatient. Demographics, comorbidities, surgical information, and administrative information were collected. Simple and multivariable logistic regression analyses were conducted comparing AMS patients and OS/inpatient as well as OS and inpatients. Results. Of the 1096 patients, 641 (58%) patients were converted to either OS (n=486) or inpatient (n=155). The multivariable analysis demonstrated that age (more than 80 yr old), high American Society of Anesthesiologists Physical Status (ASA) grade, history of sleep apnea, drain use, high estimated blood loss, long operation, late operation start time, and a high pain score were considered independent risk factors for AMS conversion to OS/inpatient. The risk factors for OS conversion to inpatient were an ASA class 3 or higher, coronary artery disease, diabetes mellitus, hypothyroidism, steroid use, drain use, dural tear, and laminectomy. Conclusions. Several surgical factors along with patient-specific factors were significantly associated with AMS conversion. Addressing modifiable surgical factors might reduce the AMS conversion rate and be beneficial to patients and facilities.

BackgroundA substantial number of randomized controlled trial (RCT) studies in total joint arthroplasty (TJA) are published each year in the United States (US). However, it is unknown how closely the demographic and clinical characteristics of these cohorts resemble that of the US patient population undergoing TJA. Thus, the purpose of this systematic review was to evaluate the patient characteristics of published RCTs in TJA in the US and to compare these characteristics against patient cohorts from national patient databases.MethodsRCT studies regarding primary TJA conducted in the US were selected. Key patient demographics were aggregated and compared against demographics characteristics of the Healthcare Cost and Utilization Project of the Agency for Healthcare Research and Quality National Inpatient Sample (NIS) and American College of Surgeons National Surgical Quality Improvement Program patient cohorts.ResultsOne hundred and fifty-three RCTs fulfilled the inclusion criteria and were included. The total number of patients in the 153 RCTs was 24,135 patients. The average age of patients in the TJA RCT cohort was 65 years (53-80) while the NIS cohort was 67 years (18-90) (d = 0.21, effect size = small). The average body mass index of the TJA RCT cohort was 30.8 (18.2-37.6) while the National Surgical Quality Improvement Program cohort was 31.9 (14.1-59.6) (d = 0.18, effect size = small). For TJA, effect sizes for age, body mass index BMI, sex, ethnicity, smoking, and diabetes were all small or very small.ConclusionOverall, the US RCT patient cohort for TJA does not differ substantially from the general patient population undergoing TJA in the United States. Differences in demographic and clinical characteristics between the TJA RCT cohort and database cohorts ranged from minimal to small, suggesting that these differences are unlikely to impact clinical outcomes.

Study Design. A retrospective cross-sectional study. Objective. To assess the association between spinal muscle morphology and spinopelvic parameters in lumbar fusion patients, with a special emphasis on lumbar lordosis (LL). Summary of Background Data. Maintenance of sagittal alignment relies on muscle forces, but the basic association between spinal muscles and spinopelvic parameters is poorly understood. Materials and Methods. Patients operated between 2014 and 2017 who had both lumbar magnetic resonance imaging scan and standing whole-spine radiographs within six months before surgery were included. Muscle measurements were conducted on axial T2-weighted magnetic resonance images at the superior endplate L3–L5 for the psoas and L3–S1 for combined multifidus and erector spinae (paraspinal) muscles. A pixel intensity threshold method was used to calculate the total cross-sectional area (TCSA) and the functional cross-sectional area (FCSA). Spinopelvic parameters were measured on lateral standing whole-spine radiographs and included LL, pelvic incidence (PI), PI-LL mismatch, pelvic tilt, sacral slope, thoracic kyphosis, and sagittal vertical axis. Analyses were stratified by biological sex. Multivariable linear regression analyses with adjustments for age and body mass index (BMI) were performed. Results. A total of 104 patients (62.5% female) were included in the analysis. The patient population was 90.4% White with a median age at surgery of 69 years and a median BMI of 27.8 kg/m2. All muscle measurements were significantly smaller in women. PI, pelvic tilt, and thoracic kyphosis were significantly greater in women. PI-LL mismatch was 6.1° (10.6°) in men and 10.2° (13.5°) in women (P=0.106), and sagittal vertical axis was 45.3 (40.8) mm in men and 35.7 (40.8) mm in women (P=0.251). After adjusting for age and BMI, paraspinal TCSA at L3–L5, and paraspinal FCSA at L4 showed significant positive associations with LL in women. In men, psoas TCSA at L5 and psoas FCSA at L5 showed significant negative associations with LL, but none of the paraspinal muscle measurements. Conclusion. Our findings indicate that psoas and lumbar spine extensor muscles interact differently on LL among men and women, creating a unique mechanical environment. Level of Evidence. Level 4.

OBJECTIVE:Changes to neurosurgical practices during the coronavirus disease 2019 (COVID-19) pandemic have not been thoroughly analyzed. We report the effects of operative restrictions imposed under variable local COVID-19 infection rates and health care policies using a retrospective multicenter cohort study and highlight shifts in operative volumes and subspecialty practice.METHODS:Seven academic neurosurgery departments' neurosurgical case logs were collected; procedures in April 2020 (COVID-19 surge) and April 2019 (historical control) were analyzed overall and by 6 subspecialties. Patient acuity, surgical scheduling policies, and local surge levels were assessed.RESULTS:Operative volume during the COVID-19 surge decreased 58.5% from the previous year (602 vs. 1449, P = 0.001). COVID-19 infection rates within departments' counties correlated with decreased operative volume (r = 0.695, P = 0.04) and increased patient categorical acuity (P = 0.001). Spine procedure volume decreased by 63.9% (220 vs. 609, P = 0.002), for a significantly smaller proportion of overall practice during the COVID-19 surge (36.5%) versus the control period (42.0%) (P = 0.02). Vascular volume decreased by 39.5% (72 vs. 119, P = 0.01) but increased as a percentage of caseload (8.2% in 2019 vs. 12.0% in 2020, P = 0.04). Neuro-oncology procedure volume decreased by 45.5% (174 vs. 318, P = 0.04) but maintained a consistent proportion of all neurosurgeries (28.9% in 2020 vs. 21.9% in 2019, P = 0.09). Functional neurosurgery volume, which declined by 81.4% (41 vs. 220, P = 0.008), represented only 6.8% of cases during the pandemic versus 15.2% in 2019 (P = 0.02).CONCLUSIONS:Operative restrictions during the COVID-19 surge led to distinct shifts in neurosurgical practice, and local infective burden played a significant role in operative volume and patient acuity.

BACKGROUND CONTEXT Pathophysiological conditions during aging can affect bone and muscle simultaneously, such as in osteosarcopenia. The vertebral bone quality (VBQ) score based on magnetic resonance imaging (MRI) was recently introduced as a novel measure of bone quality in the lumbar spine and shown to be a significant predictor of healthy versus osteopenic/osteoporotic bone. However, the association between quantitative lumbar spinal muscle parameters and the VBQ score, is unknown. PURPOSE This study aimed to assess possible associations between the functional cross-sectional area (FCSA) of psoas and lumbar spine extensor muscles (multifidus and erector spinae) and the VBQ score. STUDY DESIGN/SETTING Retrospective cohort study. PATIENT SAMPLE Patients who underwent open posterior lumbar fusion for degenerative conditions between 2014 and 2017 at a single academic institution and had both a lumbar MRI and a computed tomography (CT) scan within 6 months prior to surgery were included. OUTCOME MEASURES FCSA and VBQ score. METHODS MRI measurements included psoas and combined multifidus and erector spinae (paraspinal) FCSA at the L3-L5 superior endplate. Following manual segmentation of muscles on axial T2-weighted images using ITK-SNAP (version 3.8), the FCSA was calculated using a custom written program on Matlab (version R2019a, The MathWorks, Inc.) that used an automated pixel intensity threshold method to differentiate between fat (high intensity) and muscle (low intensity). VBQ measurements included the signal intensity of the medullary portion of the vertebrae L1-L4 and the cerebrospinal fluid (CSF) at L3 on mid-sagittal T1-weighted MR images. The VBQ score was calculated by dividing the median signal intensity L1-L4 through the signal intensity of the CSF. Lumbar volumetric bone mineral density (vBMD) was assessed by quantitative CT using the L1/2 average, categorizing patients with a vBMD of <120 mg/cm³ as osteopenic/osteoporotic. All analyses were stratified by biological sex. Sperman correlation and multivariate linear regression analysis with adjustments for age and body mass index (BMI) were performed. RESULTS Eighty patients (58.8% female) were included in the analysis. The patient population was 93.8% Caucasian with a median age at surgery of 68.8 years. The prevalence of chronic low back pain >12 weeks was 83.8%, and the prevalence of osteopenia/osteoporosis was 65%, with no significant differences between men and women. All muscle measurements were significantly greater in men. The mean (SD) VBQ score was significantly smaller in men, at 2.26 (0.45) versus women at 2.59 (0.39) (p = 0.001). In men, a significant negative correlation was seen between psoas FCSA at L3-5 and the VBQ score, with correlation coefficients ranging from -0.487 to -0.405. After adjusting for age and BMI, a significant negative association was seen between psoas FCSA at L3 and the VBQ score in men (β = -0.373; 95% CI -0.687 - -0.058; p = 0.022). In women, there was a significant negative correlation between paraspinal FCSA at L3 and the VBQ score, with a correlation coefficient of -0.367 (p = 0.011), but no significant association was seen in the adjusted analysis. CONCLUSIONS We found the VBQ score to be negatively associated with psoas FCSA at L3 among male individuals, irrespective of age and BMI. Our results highlight sex differences in the VBQ score that were not demonstrated by vBMD or categorial bone status, and suggest a potential role of this novel measure to assess not only bone quality, but also spinal muscle quantity. Further studies are needed to assess the clinical utility of the VBQ score as a non-invasive screening tool for osteosarcopenia. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs. Pathophysiological conditions during aging can affect bone and muscle simultaneously, such as in osteosarcopenia. The vertebral bone quality (VBQ) score based on magnetic resonance imaging (MRI) was recently introduced as a novel measure of bone quality in the lumbar spine and shown to be a significant predictor of healthy versus osteopenic/osteoporotic bone. However, the association between quantitative lumbar spinal muscle parameters and the VBQ score, is unknown. This study aimed to assess possible associations between the functional cross-sectional area (FCSA) of psoas and lumbar spine extensor muscles (multifidus and erector spinae) and the VBQ score. Retrospective cohort study. Patients who underwent open posterior lumbar fusion for degenerative conditions between 2014 and 2017 at a single academic institution and had both a lumbar MRI and a computed tomography (CT) scan within 6 months prior to surgery were included. FCSA and VBQ score. MRI measurements included psoas and combined multifidus and erector spinae (paraspinal) FCSA at the L3-L5 superior endplate. Following manual segmentation of muscles on axial T2-weighted images using ITK-SNAP (version 3.8), the FCSA was calculated using a custom written program on Matlab (version R2019a, The MathWorks, Inc.) that used an automated pixel intensity threshold method to differentiate between fat (high intensity) and muscle (low intensity). VBQ measurements included the signal intensity of the medullary portion of the vertebrae L1-L4 and the cerebrospinal fluid (CSF) at L3 on mid-sagittal T1-weighted MR images. The VBQ score was calculated by dividing the median signal intensity L1-L4 through the signal intensity of the CSF. Lumbar volumetric bone mineral density (vBMD) was assessed by quantitative CT using the L1/2 average, categorizing patients with a vBMD of <120 mg/cm³ as osteopenic/osteoporotic. All analyses were stratified by biological sex. Sperman correlation and multivariate linear regression analysis with adjustments for age and body mass index (BMI) were performed. Eighty patients (58.8% female) were included in the analysis. The patient population was 93.8% Caucasian with a median age at surgery of 68.8 years. The prevalence of chronic low back pain >12 weeks was 83.8%, and the prevalence of osteopenia/osteoporosis was 65%, with no significant differences between men and women. All muscle measurements were significantly greater in men. The mean (SD) VBQ score was significantly smaller in men, at 2.26 (0.45) versus women at 2.59 (0.39) (p = 0.001). In men, a significant negative correlation was seen between psoas FCSA at L3-5 and the VBQ score, with correlation coefficients ranging from -0.487 to -0.405. After adjusting for age and BMI, a significant negative association was seen between psoas FCSA at L3 and the VBQ score in men (β = -0.373; 95% CI -0.687 - -0.058; p = 0.022). In women, there was a significant negative correlation between paraspinal FCSA at L3 and the VBQ score, with a correlation coefficient of -0.367 (p = 0.011), but no significant association was seen in the adjusted analysis. We found the VBQ score to be negatively associated with psoas FCSA at L3 among male individuals, irrespective of age and BMI. Our results highlight sex differences in the VBQ score that were not demonstrated by vBMD or categorial bone status, and suggest a potential role of this novel measure to assess not only bone quality, but also spinal muscle quantity. Further studies are needed to assess the clinical utility of the VBQ score as a non-invasive screening tool for osteosarcopenia.

Diarrhea remains a significant cause of morbidity and mortality among children in developing countries. Water, sanitation, and hygiene practices (WASH) have demonstrated improved diarrhea-related outcomes but may have limited implementation in certain communities. This study analyzes the adoption and effect of WASH-based practices on diarrhea in children under age five in the rural Busiya chiefdom in northwestern Tanzania. In a cross-sectional analysis spanning July-September 2019, 779 households representing 1338 under-five children were surveyed. Among households, 250 (32.1%) reported at least one child with diarrhea over a two-week interval. Diarrhea prevalence in under-five children was 25.6%. In per-household and per-child analyses, the strongest protective factors against childhood diarrhea included dedicated drinking water storage (OR 0.25, 95% CI 0.18–0.36; p < 0.001), improved waste management (OR 0.37, 95% CI 0.27–0.51; p < 0.001), and separation of drinking water (OR 0.38, 95% CI 0.24–0.59; p < 0.001). Improved water sources were associated with decreased risk of childhood diarrhea in per-household analysis (OR 0.72, 95% CI 0.52–0.99, p = 0.04), but not per-child analysis (OR 0.83, 95% CI 0.65–1.05, p = 0.13). Diarrhea was widely treated (87.5%), mostly with antibiotics (44.0%) and oral rehydration solution (27.3%). Targeting water transportation, storage, and sanitation is key to reducing diarrhea in rural populations with limited water access.

..................................................................................................................... 3 Introduction ................................................................................................................ 4 Experimental Detail ................................................................................................... 6 Results ........................................................................................................................ 9 Discussion ................................................................................................................14 Conclusions ..............................................................................................................16 Acknowledgements ..................................................................................................16 References ................................................................................................................17

Hypoxia is a common feature in solid tumors. Clinical samples show a positive correlation between the expression of the hypoxia-inducible factor HIF-1α and estrogen receptor alpha (ERα) and a negative correlation between HIF-1α and hormone sensitivity. Results from monolayer cultures are in contention with clinical observations, showing that ER (+) cell lines no longer express ERα under hypoxic conditions (1% O2). Here, we compared the impact of hypoxia on the ERα signaling pathway for T47D cells in a 2D and 3D culture format. In the 2D format, the cells were cultured as monolayers. In the 3D format, paper-based scaffolds supported cells suspended in a collagen matrix. Using ELISA, Western blot, and immunofluorescence measurements, we show that hypoxia differentially regulates ERα protein levels in a culture environment-dependent manner. In the 2D format, the protein levels are significantly decreased in hypoxia. In the 3D format, the protein levels are maintained in hypoxia. Hypoxia reduced ERα transcriptional activation in both culture formats. These results highlight the importance of considering tissue dimensionality for in vitro studies. They also show that ERα protein levels in hypoxia are not an accurate indicator of ERα transcriptional activity, and confirm that a positive stain for ERα in a clinical sample may not necessarily indicate hormone sensitivity.

The Briggs-Rauscher (BR) oscillatory reaction is one of the more interesting and colorful oscillatory reactions. It has surpassed the demonstration realm, as it has found use as a method to assess antioxidant capacity. However, this application as an antioxidant assay is limited to water-soluble samples. In the constant search for different, novel applications, we report the effects of various sample solvents on the behavior of the BR reaction. Our investigation looked at how changes in the solvent used to dissolve samples altered the time intervals of BR reaction’s oscillations. The solvents used were ethanol, isopropanol, 1-propanol, acetone, and acetonitrile. Addition of ethanol had no effect on the BR oscillations. Isopropanol, 1-propanol, and acetone shorten the oscillation time. A test using acetonitrile discarded solvent polarity effects. Our results suggest that solvents that accelerate the enol pathway rate affect the oscillations of the BR reaction. Finally, samples can be safely dissolved in ethanol and used in the BR reaction.

Antioxidant Capacity of Common Dietary Supplements Ana Figuereo, Marie Roche, Leonardo Albertini, Chelsea Trost, and Luis C. Fernandez-Torres School of Science, Technology, and Engineering Management, St. Thomas University, Miami Gardens, FL 33054 Today’s health-conscious society consumes a wide variety of dietary supplements in order to improve quality of life. An increasing number of these supplements are marketed as antioxidants. Therefore, it is of great importance to understand the performance of these supplements as antioxidants. This investigation presents the antioxidant capacity of several common dietary supplements using the Briggs-Rauscher (BR) oscillatory reaction. The antioxidant species scavenge free radicals formed in the BR reaction, lengthening the time intervals of the reaction’s oscillations; the higher the antioxidant capacity, the longer the oscillation delays. The samples experimented, Beta carotene, Lutein, Quercetin, Folic Acid, and L-Glutathione, all exhibit antioxidant activity. Trolox, a water-soluble form of vitamin E, was established as the standard to assess each supplement’s antioxidant capacity. It was noted that the time delay within the BR reaction oscillations was significantly affected with increasing concentrations of each substance. Also, sodium iodate proved to be better than potassium iodate in the BR reaction, as precipitation was not a factor that altered results in the BR reaction. In addition the antioxidant capacity was quantified by the calculation of the Relative Antioxidant Performance (RAP), which measures the sample slope over the standard slope or the slope of Trolox. Finally, we observed that exposure to light can affect the antioxidant capacity.