The determination of sodium in biological fluids

Dissertation (Ph.D.)--Boston University, 1939. This item was digitized by the Internet Archive

Oxidation-reduction potentials and their application to soils

Thesis (M.S.

Effect of Carbohydrate-electrolyte Feedings on Knee Biomechanics and Postural Stability During Intermittent High-Intensity Exercise to Fatigue

Fatiguing exercise alters neuromuscular and biomechanical characteristics that increase athlete’s risk for non-contact lower extremity injury. Sports nutrition research has demonstrated the ability to delay fatigue and improve performance through carbohydrate feedings. However, the effect of nutrition on delaying neuromuscular risk factors affected by exercise and fatigue has not been examined. The purpose of this study was to evaluate the effects of a carbohydrate-electrolyte (CHO-E) beverage compared to a placebo (PLA) on landing kinematics, balance, and muscle activation patterns throughout an intermittent high-intensity exercise (IHE) protocol. The IHE protocol was designed to mimic sports competition and has demonstrated the ability to induce changes in landing mechanics during pilot testing. A total of 24 (12 male/12 female) athletes (age: 23.0±4.0yrs; height: 173.3±7.1cm; weight: 72.9±11.5kg; body fat: 18.0±6.4%) completed three days of testing. The first day of testing consisted of anthropometrics and familiarization with the IHE protocol. The next two testing sessions participants performed four quarters of IHE while consuming either a CHO-E or PLA beverage. Landing kinematics, muscle activation, and dynamic postural stability index (DPSI) scores were assessed immediately before, at break three, and break four of the IHE protocol. The DPSI scores were measured during a single-leg jump landing. Landing kinematics (knee flexion and valgus/varus at initial contact, and peak hip flexion) and muscle activity (surface electromyography pre-activity and re-activity of the hamstrings and quadriceps) were measured during a single-leg stop-jump. Separate two-way repeated measures analysis of variance was performed to determine the interaction between time and treatment for landing kinematics and DPSI. Change in muscle activation was examined using a related samples Wilcoxon Signed Rank test. The CHO-E beverage had no effect on preventing changes in knee flexion at initial contact (p=0.472), peak hip flexion (p=0.456), and muscle activation (p>0.05). A significant interaction effect occurred for DPSI scores (p=0.023) and knee valgus/varus at initial contact (p=0.007) however, these changes were small and lack clinical significance. Consuming a 6% CHO-E beverage before, during, and after IHE had no effect on preventing neuromuscular/biomechanical changes occurring as a result of IHE. Future studies should continue to investigate nutritional approaches for injury prevention

Acute Beet Juice Supplementation Does Not Improve 30- or 60-second Maximal Intensity Performance in Anaerobically Trained Athletes

International Journal of Exercise Science 14(2): 60-75, 2021. Research suggests that beet juice is beneficial during aerobic exercise. However, the impact of beet juice during primarily anaerobic exercise is equivocal. The purpose of this study was to determine the effects of acute beet juice supplementation on maximal intensity performance during 30-s and 60-s maximal-intensity cycling sprints. Using a double-blind, crossover-study design, 14 anaerobically trained male hockey players completed six Wingate cycling tests: familiarization trials of a 30-s and 60-s Wingate test, followed by 30-s Wingate placebo/beet juice trials, and 60-s Wingate placebo/beet juice trials. Repeated measures ANOVAs were used to compare the change in power between conditions over the duration of each trial. Paired t-tests were run to compare performance between conditions of various work and power variables. One-way ANOVAs were utilized to compare the change between conditions of the 30-s test to the change between conditions of the 60-s test. Beet juice supplementation yielded no statistical differences from placebo in any of the measured variables during the 30-s or 60-s tests (p \u3e 0.05). The percent change for fatigue index was significantly different between the 30-s and 60-s tests (p = 0.032) suggesting less fatigue with beet juice supplementation. Overall, beet juice did not improve maximal intensity performance during 30-s or 60-s cycling sprint tests. Performance during the 60-s bout was not impacted to a greater extent than the 30-s bout after beet juice supplementation. These results suggest that beet juice supplementation does not improve short-duration exercise performance in anaerobically trained athletes

Life Stage, Gender and Movement of Blue Crabs (Callinectis sapidus) in Lake Mattamuskeet and Connecting Canals

In their ranges on east and south coasts of the Americas as well as their established invasions in the Adriatic and Baltic, blue crabs, Callinectis sapidus, inhabit estuaries, sounds and coastal oceans and are commercially and ecologically important. How crabs move in response to physical variables is important to management. We monitored life stages at canal control structures, assessed gender ratios with recreational crabbing, learned from crabbers, and studied movements of tagged crabs in a canal connecting Lake Mattamuskeet to the Pamlico sound.  Juveniles enter the lake  through two of 4 canals connecting to the sounds.  Females migrate out through one canal. The lake standing population is about 70% male.  Movements of 240 crabs in August 2012 and 102 crabs in October 2014 were quantified using RFID tags with co-located meteorological and oceanographic devices. Non-spawning females and males are nomadic.  Crabs released in the canal move in response to changes in water depth and go with the flow, toward the Pamlico Sound (summer 76% and fall 78%). What crabbers describe as a fall migration  appears to be concentration of crabs in warmer deeper canals and then southern movement with flow generated by strong north winds. To be effective, management strategies like migratory corridors require understanding of crab movements

Comparison and Correlation of Dynamic Postural Stability Indices Obtained during Different Dynamic Landing Tasks and Footwear Conditions

Objectives: To compare the dynamic postural stability indices (DPSI) from two different landing protocols with normalized jump distance (NDP) and jump height (RWDP) and footwear conditions (barefoot and shod).Design: Cross-sectional.Setting: Research laboratory.Participants: Twenty-five physically active adults (13 males/12 females, age: 22.1±4.2yrs, height: 178.3±11.1cm, weight: 75.6±19.4kg).Main Outcome Measures: Subjects jumped off two feet and landed with their preferred foot on a force-plate. From the ground reaction forces, the DPSI scores in the anterior-posterior, medial-lateral, and vertical directions, and the cumulative scores (DPSI) were calculated under two protocols and footwear conditions. Based on normality of data distribution, paired t-tests/Wilcoxon signed rank tests and Pearson/Spearman correlation coefficients were used to compare, and measure the relationship between the two protocols under two footwear conditions (p<0.05).Results: There were mixed results for DPSI scores when comparing the two protocols. There were significant differences (p=0.001–0.039) and positive correlations (r=0.660–0.870, p<0.001) on the DPSI scores between footwear conditions during the NDP protocol while the RWDP showed no significant differences.Conclusions: Different protocols and footwear conditions may impact DPSI scores. Therefore, a standardized protocol and footwear condition should be established for future studies examining dynamic postural stability

THE EFFECT OF LOADED FATIGUE ON LOADED POSTURAL STABILITY

Military personnel are often required to carry heavy loads for long distances over unpredictable terrain. Additional load carriage, in conjunction with fatigue, has the potential to influence postural control mechanisms which may in turn increase injury risk. The purpose of this study was to determine if a loaded incremental march to fatigue negatively influences loaded postural stability. Loaded postural stability was measured using the NeuroCom Sensory Organization Test (SOT) and kinetic force plate variables (vertical ground reaction forces: SDvGRF, and TotSway) before and after a loaded incremental march to fatigue in 23 physically active men and women (age: 24.1 4.0 years, height: 172.3 11.1 cm, weight: 162.2 38.2 lbs) while subjects were adorned with a weighted vest equating to 30% of their body weight. The SOT consisted of six conditions (C1-C6) aimed to perturb the sensorimotor system, which were performed before and after a loaded fatigue protocol. C1, C2 and C3 challenged the somatosensory system, C4 challenged the visual system, while C5 and C6 challenged the vestibular system. Fatigue was induced with a treadmill march at 4mph with increasing grades of 2% every three minutes until volitional fatigue. After testing for normality, paired sample t-tests or Wilcoxon signed rank tests were conducted to assess pre- to post-fatigue differences. Significant reductions in SOT scores were found in overall composite scores (pre: 82.8 4.7, post: 81.6 5.2, p = 0.010), SDvGRF of C1 (pre: 1.3 0.5, post: 2.0 0.9, p < 0.001), C2 (pre: 1.4 0.6, post: 1.9 1.2, p < 0.001), C3 (pre: 1.4 0.5, post: 2.1 1.8, p = 0.026), and C6 (pre: 2.5 2.2, post: 3.5 3.2, p < 0.001) and TotSway of all conditions. Results suggest that significant changes in loaded postural stability were caused by loaded fatigue. Findings could aid in future postural stability screenings, load carriage training and strategies for injury prevention in the military

Outcome and biomarker analysis from a multi-centre phase 2 study of ipilimumab in combination with carboplatin and etoposide (ICE) as first line therapy for extensive stage small cell lung cancer.

BACKGROUND: To evaluate safety and efficacy of ipilimumab combined with standard first-line chemotherapy for patients with extensive stage SCLC. METHODS: Chemotherapy-naïve extensive stage SCLC patients were treated with carboplatin and etoposide up to six cycles. Ipilimumab 10 mg/kg was given on day 1 of cycles 3-6 and every 12 weeks. Response was assessed by RECIST v1.0 and immune related response criteria (irRC). The primary endpoint was 1-year progression-free survival (PFS) according to RECIST. Secondary endpoints included PFS by irRC (irPFS) and overall survival (OS). Autoantibody serum levels were evaluated and correlated with clinical outcomes. RESULTS: 42 patients were enrolled between September 2011-April 2014, 39 evaluable for safety and 38 for efficacy. 6/38 patients (15.8% [95% CI: 7.4%-30.4%]) were alive and progression-free at 1-year by RECIST. Median PFS was 6.9 months (95%CI: 5.5-7.9). Median irPFS was 7.3 months (95% CI: 5.5-8.8). Median OS was 17.0 months (95% CI: 7.9-24.3). In patients evaluable for response, 21/29 patients (72.4%) achieved an objective response by RECIST and 28/33 (84.8%) by irRC. All patients experienced at least one adverse event; 35/39 (89.7%) patients developed at least one toxicity ≥ Grade 3; in 27 (69.2%) this was related to ipilimumab. Five deaths were reported to be related to ipilimumab. The positivity of an autoimmune profile at baseline was associated with improved outcomes and severe neurological toxicity. CONCLUSION: Ipilimumab in combination with carboplatin and etoposide might benefit a subgroup of patients with advanced SCLC. Autoantibody analysis correlates with treatment benefit and toxicity and warrants further investigation

An Employment Intervention Program (Work2Prevent) for Young Men Who Have Sex With Men and Transgender Youth of Color (Phase 1): Protocol for Determining Essential Intervention Components Using Qualitative Interviews and Focus Groups

BACKGROUND: HIV continues to have a disparate impact on young cisgender men who have sex with men (YMSM), young trans women (YTW), and gender-nonconforming (GNC) youth who are assigned male at birth. Outcomes are generally worse among youth of color. Experiences of discrimination and marginalization often limit educational attainment and may even more directly limit access to gainful employment. Though seemingly distal, these experiences influence young people's proximity to HIV risk by limiting their access to health care and potentially moving them toward sex work as a means of income as well as increased substance use. Work2Prevent (W2P) aims to achieve economic stability through employment as a structural-level intervention for preventing adolescent and young adult HIV infection. The study will pilot-test an effective, theoretically driven employment program (increased individual income and independence [iFOUR]), for HIV-positive adults, and adapt it to the needs of black and Latinx YMSM, YTW, and GNC youth aged 16 to 24 years who are vulnerable to HIV exposure. OBJECTIVE: This paper aimed to describe the protocol for the exploratory phase of W2P. The purpose of this phase was to determine the essential components needed for a structural-level employment intervention aimed at increasing job-seeking self-efficacy and career readiness among black and Latinx YMSM, YTW, and GNC youth aged 16 to 24 years. METHODS: The exploratory phase of the W2P study consisted of in-depth interviews and focus groups with members of the target community as well as brief interviews with lesbian, gay, bisexual, transgender, and queer (LGBTQ)-inclusive employers. The study team will conduct in-depth interviews with up to 12 YMSM and 12 YTW and GNC youth, up to 10 focus groups with a maximum of 40 YMSM and 40 YTW and GNC youth, and up to 40 brief interviews with LGBTQ-inclusive employers. Participants will be recruited through a community-based recruiter, passive recruitment in community spaces and on social media, and active recruitment by research staff in community spaces serving LGBTQ youth. RESULTS: In-depth interviews were conducted with 21 participants, and 7 focus groups were conducted with 46 participants in total. In addition, 19 brief interviews with LGBTQ-inclusive employers were conducted. The analysis of the data is underway. CONCLUSIONS: Preliminary findings from the formative phase of the study will be used to inform the tailoring and refinement of the iFOUR adult-based intervention into the youth-focused W2P intervention curriculum. Perspectives from YMSM, YTW, GNC youth, and LGBTQ-inclusive employers offer a multidimensional view of the barriers and facilitators to adolescent and young adult LGBTQ employment. This information is critical to the development of a culturally appropriate and relevant youth-focused intervention

An Employment Intervention Program (Work2Prevent) for Young Men Who Have Sex With Men and Transgender Youth of Color (Phase 2): Protocol for a Single-Arm Mixed Methods Pilot Test to Assess Feasibility and Acceptability

BACKGROUND: Young cisgender men who have sex with men (YMSM), young transgender women (YTW), and gender nonconforming (GNC) youth of color face substantial economic and health disparities. In particular, HIV risk and infection among these groups remains a significant public health issue. In 2017, 17% of all new HIV diagnoses were attributed to male-to-male sexual contact among adolescents and young adults aged 13 to 24 years. However, such disparities cannot be attributed to individual-level factors alone but rather are situated within larger social and structural contexts that marginalize and predispose YMSM, YTW, and GNC youth of color to increased HIV exposure. Addressing social and structural risk factors requires intervention on distal drivers of HIV risk, including employment and economic stability. The Work2Prevent (W2P) study aims to target economic stability through job readiness and employment as a structural-level intervention for preventing adolescent and young adult HIV among black and Latinx YMSM, YTW, and GNC youth. This study seeks to assess intervention feasibility and acceptability in the target populations and determine preliminary efficacy of the intervention to increase employment and reduce sexual risk behaviors. OBJECTIVE: The goal of the research is to pilot-test a tailored, theoretically informed employment intervention program among YMSM, YTW, and GNC youth of color. This intervention was adapted from Increased Individual Income and Independence, an existing evidence-based employment program for HIV-positive adults during phase 1 of the W2P study. METHODS: The employment intervention will be pilot-tested among vulnerable YMSM, YTW, and GNC youth of color in a single-arm pre-post trial to assess feasibility, acceptability, and preliminary estimates of efficacy. RESULTS: Research activities began in March 2018 and were completed in November 2019. Overall, 5 participants were enrolled in the pretest and 51 participants were enrolled in the pilot. CONCLUSIONS: Interventions that address the social and structural drivers of HIV exposure and infection are sorely needed in order to successfully bend the curve in the adolescent and young adult HIV epidemic. Employment as prevention has the potential to be a scalable intervention that can be deployed among this group